Microglia and Alzheimer

  1. Asanuma M, Miyazaki I, Tsuji T, Ogawa N (2003) [New aspects of neuroprotective effects of nonsteroidal anti-inflammatory drugs]. Nihon Shinkei Seishin Yakurigaku Zasshi 23:111-119
    Abstract: Nonsteroidal anti-inflammatory drugs (NSAIDs) exert anti-inflammatory, analgesic and antipyretic activities and are involved in the suppression of prostaglandin synthesis by inhibiting cyclooxygenase (COX), a prostaglandin synthesizing enzyme. It has been recently revealed that NSAIDs also possess inhibitory effects on the generating system of nitric oxide radicals and modulating effects on transcription factors and nuclear receptors which are related to inflammatory reactions. Since it has been reported that inflammatory processes are associated with the pathophysiology of several neurodegenerative diseases and that NSAIDs inhibit amyloid beta-protein-induced neurotoxicity to reduce the risk for Alzheimer's disease, a number of studies have been conducted focusing on the neuroprotective effects of NSAIDs. It has been clarified that the drugs exert neuroprotective effects, which are not related to their COX-inhibiting property, on pathophysiology of various neurological disorders. In this article, new aspects of neuroprotective effects of NSAIDs have been reviewed, especially, in Alzheimer's disease and Parkinson's disease, discussing various pharmacological effects of NSAIDs other than their inhibitory action on COX

  2. Bard F, Barbour R, Cannon C, Carretto R, Fox M, Games D, Guido T, Hoenow K, Hu K, Johnson-Wood K, Khan K, Kholodenko D, Lee C, Lee M, Motter R, Nguyen M, Reed A, Schenk D, Tang P, Vasquez N, Seubert P, Yednock T (2003) Epitope and isotype specificities of antibodies to beta -amyloid peptide for protection against Alzheimer's disease-like neuropathology. Proc.Natl.Acad.Sci.U.S.A 100:2023-2028
    Abstract: Transgenic PDAPP mice, which express a disease-linked isoform of the human amyloid precursor protein, exhibit CNS pathology that is similar to Alzheimer's disease. In an age-dependent fashion, the mice develop plaques containing beta-amyloid peptide (Abeta) and exhibit neuronal dystrophy and synaptic loss. It has been shown in previous studies that pathology can be prevented and even reversed by immunization of the mice with the Abeta peptide. Similar protection could be achieved by passive administration of some but not all monoclonal antibodies against Abeta. In the current studies we sought to define the optimal antibody response for reducing neuropathology. Immune sera with reactivity against different Abeta epitopes and monoclonal antibodies with different isotypes were examined for efficacy both ex vivo and in vivo. The studies showed that: (i) of the purified or elicited antibodies tested, only antibodies against the N-terminal regions of Abeta were able to invoke plaque clearance; (ii) plaque binding correlated with a clearance response and neuronal protection, whereas the ability of antibodies to capture soluble Abeta was not necessarily correlated with efficacy; (iii) the isotype of the antibody dramatically influenced the degree of plaque clearance and neuronal protection; (iv) high affinity of the antibody for Fc receptors on Microglial cells seemed more important than high affinity for Abeta itself; and (v) complement activation was not required for plaque clearance. These results indicate that antibody Fc-mediated plaque clearance is a highly efficient and effective process for protection against neuropathology in an animal model of Alzheimer's disease

  3. Blasko I, Grubeck-Loebenstein B (2003) Role of the immune system in the pathogenesis, prevention and treatment of Alzheimer's disease. Drugs Aging 20:101-113
    Abstract: The dysregulation in the metabolism of beta-amyloid precursor protein and consequent deposition of amyloid-beta (Abeta) has been envisaged as crucial for the development of neurodegeneration in Alzheimer's disease (AD). Amyloid deposition begins 10-20 years before the appearance of clinical dementia. During this time, the brain is confronted with increasing amounts of toxic Abeta peptides and data from the last decade intriguingly suggest that both the innate and the adaptive immune systems may play an important role in the disorder. Innate immunity in the brain is mainly represented by Microglial cells, which phagocytose and degrade Abeta. As the catabolism of Abeta decreases, glial cells become overstimulated and start to produce substances that are toxic to neurons, such as nitric oxide and inflammatory proteins. Pro-inflammatory cytokines can be directly toxic or stimulate Abeta production and increase its cytotoxicity. A therapeutic possibility arises from clinical studies, which demonstrate that nonsteroidal anti-inflammatory drugs (NSAIDs) may delay the onset and slow the progression of AD. Recent data show that in addition to the suppression of inflammatory processes in the brain NSAIDs may decrease the production of Abeta peptides. The role of adaptive immunity lies mainly in the fact that Abeta can be recognised as an antigen. Immunisation with Abeta peptides and peripheral administration of Abeta-specific antibodies both decrease senile plaques and cognitive dysfunction in murine models of AD. A recent trial in humans seems still to be hampered by adverse effects. As adaptive immunity decreases with aging while innate immunity remains intact, immunotherapy for AD will have to be adapted to this situation. Strategies that combine vaccination and inflammatory drug treatment could be considered

  4. Chaney MO, Baudry J, Esh C, Childress J, Luehrs DC, Kokjohn TA, Roher AE (2003) A beta, aging, and Alzheimer's disease: a tale, models, and hypotheses. Neurol.Res. 25:581-589
    Abstract: In this paper we explore the potential functional role of the A beta peptides in the context of Alzheimer's disease (AD). We begin by defining the morphology of the amyloid deposits in relation to surrounding glial cells and, more importantly, in relation to the brain vasculature. Amyloid accumulation in the brain's microvasculature causes disturbances in the blood-brain barrier (BBB), and in larger arteries, impairment in control of regional cerebral blood flow due to myocyte degeneration. We postulate that the deposition of vascular amyloid may represent a hydrophobic protein plaster to seal leaks in the BBB, occasionally observed in aging and catastrophically common in AD. The vasoconstrictive activity of A beta may also be related to leaky vessels whereby decreasing the arterial diameter may also help to control breaches in the BBB. The admission of plasma neurotoxic proteins into the brain may be controlled by activation of Microglia elicited by soluble A beta peptides creating a subtle, but permanent brain inflammatory reaction. We also delve into the influence that cholesterol metabolism may have in membrane topology and A beta production, and the close correlations that exist between cardiovascular disease and AD. Finally, we speculate about the possibility of a peripheral source of A beta that may, by crossing the BBB, contribute to the vascular and parenchymal deposits of A beta in the AD brain

  5. Chaudhury AR, Gerecke KM, Wyss JM, Morgan DG, Gordon MN, Carroll SL (2003) Neuregulin-1 and erbB4 immunoreactivity is associated with neuritic plaques in Alzheimer disease brain and in a transgenic model of Alzheimer disease. J.Neuropathol.Exp.Neurol. 62:42-54
    Abstract: Neuregulin-1 (NRG-1) regulates developmental neuronal survival and synaptogenesis, astrocytic differentiation, and Microglial activation. Given these NRG-1 actions, we hypothesized that the synaptic loss, gliosis, inflammation, and neuronal death occurring in Alzheimer disease (AD) is associated with altered expression of NRG-1 and its receptors (the erbB2, erbB3, and erbB4 membrane tyrosine kinases). We examined the expression and distribution of NRG-1 and the erbB kinases in the hippocampus of AD patients and cognitively normal controls and in transgenic mice that coexpress AD-associated mutations of the beta amyloid precursor protein (APP(K670N,M671L)) and presenilin-1 (PS1(M146L)). In the hippocampi of both control humans and wild type mice, NRG-1 and the 3 erbB receptors are expressed in distinct cellular compartments of hippocampal neurons. All 4 molecules are associated with neuronal cell bodies, but only NRG-1, erbB2, and erbB4 are present in synapse-rich regions. In AD and in the doubly transgenic mouse, erbB4 is expressed by reactive astrocytes and Microglia surrounding neuritic plaques. In AD brains, Microglia and, to a lesser extent, dystrophic neurites, also upregulate NRG-1 in neuritic plaques, suggesting that autocrine and/or paracrine interactions regulate NRG-1 action within these lesions. NRG-1 and erbB4, as well as erbB2, are similarly associated with neuritic plaques in the doubly transgenic mice. Thus, in AD the hippocampal distribution of NRG-1 and erbB4 is altered. The similarities between the alterations in the expression of NRG-1 and its receptors in human AD and in APP(K670N;M671L)/PS1(M146L) mutant mice suggests that this animal model may be very informative in deciphering the potential role of these molecules in AD

  6. Chauhan NB, Siegel GJ (2003) Intracerebroventricular passive immunization with anti-Abeta antibody in Tg2576. J.Neurosci.Res. 74:142-147
    Abstract: Current Alzheimer's disease (AD) research has established the fact that excessive genesis of Abeta derived from amyloidogenic processing of beta-amyloid (Abeta) precursor protein is fundamental to AD pathogenesis. There has been considerable interest in using immunization strategies for clearing excessive Abeta. Studies in animal models of AD have shown that active immunizations or systemic passive immunizations reduced cerebral plaque load and improved behavioral deficits. However, clinical translation of an active immunization strategy was interrupted because of evidence for meningoencephalitis produced in some patients who received Abeta vaccine. Studies in animal models have shown perimicrovascular hemorrhages and inflammation after sustained systemic immunizations in animals with vascular amyloid. In this light, our data showing the effects of a single intracerebroventricular (ICV) injection of anti-Abeta in the Alzheimer's Swedish mutant model Tg2576 are intriguing. We have previously demonstrated that a single ICV injection of anti-Abeta into the third ventricle of 10-month-old Tg2576 mice reduced cerebral plaques, reversed Abeta-induced depletion of presynaptic SNAP-25, and abolished astroglial activation as seen 1 month post-injection (Chauhan and Siegel [2002] J. Neurosci. Res. 69:10-23). The present report demonstrates that a single ICV injection of 10 microg anti-Abeta in 10-month-old Tg2576 mice reduced cerebral plaques, with decreased inflammation at this stage as evidenced by a reduced number of interleukin-1beta-positive Microglia surrounding Congophilic plaques. Moreover, at this particular age, no microhemorrhage was discernible, as evidenced by the absence of hemosiderin deposition after a single ICV injection of anti-Abeta. This is the first report demonstrating absence of microhemorrhage and reduced inflammation after the ICV introduction of anti-Abeta in Tg2576 mice at 10 months of age. These facts indicate that, although invasive, ICV injection of anti-Abeta may be a safer method of vaccination in AD, possibly through reducing the vascular exposure to antibody. Further studies are warranted to determine the lasting effects of a single ICV anti-Abeta injection in animals with and without abundant plaque burden and at older ages

  7. Check E (2003) Battle of the mind. Nature 422:370-372

  8. Czapiga M, Colton CA (2003) Microglial function in human APOE3 and APOE4 transgenic mice: altered arginine transport. J.Neuroimmunol. 134:44-51
    Abstract: The APOE4 genotype is a known risk factor for Alzheimer's disease (AD) and is associated with poorer outcomes after neuropathological insults. To understand APOE's function, we have examined Microglia, the CNS specific macrophage, in transgenic mice expressing the human APOE3 and APOE4 gene allele. Our data demonstrate that arginine uptake is enhanced in APOE4 Microglia compared to APOE3 Microglia. The increased arginine uptake in APOE4 Tg Microglia is associated with an increased expression of mRNA for cationic amino acid transporter-1 (Cat1), a constuitively expressed member of the arginine selective transport system (the y+ transport system) found in most cells. The macrophage-associated transporter, cationic amino acid transporter 2B (Cat2B) did not demonstrate a change in mRNA expression. This change in Microglial arginine transport suggests a potential impact of the APOE4 gene allele on those biochemical pathways such as NO production or cell proliferation to which arginine contributes

  9. Das P, Howard V, Loosbrock N, Dickson D, Murphy MP, Golde TE (2003) Amyloid-beta immunization effectively reduces amyloid deposition in FcRgamma-/- knock-out mice. J.Neurosci. 23:8532-8538
    Abstract: Direct immunization with amyloid beta protein (Abeta) and passive transfer of anti-Abeta antibodies reduce Abeta accumulation and attenuate cognitive deficits in transgenic models of Alzheimer's disease (AD). The reduction in Abeta deposition has been proposed to involve Microglial phagocytosis of Abeta immune complexes via Fc receptors (FcRs). We have examined the efficacy of Abeta immunization in amyloid precursor protein (APP) transgenic mice crossed into FcR-gamma chain knock-out mice (FcRgamma-/-). As might be expected from previous studies on macrophages, phagocytosis of Abeta immune complexes via FcR was completely impaired in Microglia cells isolated from FcRgamma-/- mice. Thus, we immunized APP Tg2576 transgenic mice that were crossed in the FcRgamma-/- background with Abeta1-42 and then analyzed the effect on Abeta accumulation. In APP Tg2576 transgenic mice crossed to FcRgamma-/-, Abeta1-42 immunization significantly attenuated Abeta deposition, as assessed by both biochemical and immunohistological methods. The reduction in Abeta accumulation was equivalent to the reduction in deposition seen in Abeta1-42 immunized, age-matched, FcR-sufficient Tg2576 mice. We conclude that after Abeta immunization, the effects of anti-Abeta antibodies on Abeta deposition in APP Tg2576 transgenic mice are not dependent on FcR-mediated phagocytic events

  10. Dodel RC, Hampel H, Du Y (2003) Immunotherapy for Alzheimer's disease. Lancet Neurol. 2:215-220
    Abstract: Recent studies in murine models of Alzheimer's disease (AD) have found that active immunisation with amyloid-beta peptide (Abeta) or passive immunisation with Abeta antibodies can lessen the severity of Abeta-induced neuritic plaque pathology through the activation of Microglia. These antibodies can be detected in the serum and CSF. Whether they slow down or speed up the development and progression of AD has not been determined. Furthermore, the conditions that induce formation of such antibodies are unknown, or how specific they are to AD. However, the evidence suggests at least a potential beneficial role for some features of neuroinflammation in AD. A clinical phase II study of an active immunisation approach with AN1792 was started in 2001, but was recently suspended after some patients developed serious adverse events. These were most likely caused by the activation of the proinflammatory cascade. Immunotherapy approaches represent fascinating ways to test the amyloid hypothesis and may offer genuine opportunities to modify disease progression. This review focuses on immunisation strategies and details of the pathways involved in antibody clearance of Abeta

  11. El Khoury JB, Moore KJ, Means TK, Leung J, Terada K, Toft M, Freeman MW, Luster AD (2003) CD36 mediates the innate host response to beta-amyloid. J.Exp.Med. 197:1657-1666
    Abstract: Accumulation of inflammatory Microglia in Alzheimer's senile plaques is a hallmark of the innate response to beta-amyloid fibrils and can initiate and propagate neurodegeneration characteristic of Alzheimer's disease (AD). The molecular mechanism whereby fibrillar beta-amyloid activates the inflammatory response has not been elucidated. CD36, a class B scavenger receptor, is expressed on Microglia in normal and AD brains and binds to beta-amyloid fibrils in vitro. We report here that Microglia and macrophages, isolated from CD36 null mice, had marked reductions in fibrillar beta-amyloid-induced secretion of cytokines, chemokines, and reactive oxygen species. Intraperitoneal and stereotaxic intracerebral injection of fibrillar beta-amyloid in CD36 null mice induced significantly less macrophage and Microglial recruitment into the peritoneum and brain, respectively, than in wild-type mice. Our data reveal that CD36, a major pattern recognition receptor, mediates Microglial and macrophage response to beta-amyloid, and imply that CD36 plays a key role in the proinflammatory events associated with AD

  12. Farris W, Mansourian S, Chang Y, Lindsley L, Eckman EA, Frosch MP, Eckman CB, Tanzi RE, Selkoe DJ, Guenette S (2003) Insulin-degrading enzyme regulates the levels of insulin, amyloid beta-protein, and the beta-amyloid precursor protein intracellular domain in vivo. Proc.Natl.Acad.Sci.U.S.A 100:4162-4167
    Abstract: Two substrates of insulin-degrading enzyme (IDE), amyloid beta-protein (Abeta) and insulin, are critically important in the pathogenesis of Alzheimer's disease (AD) and type 2 diabetes mellitus (DM2), respectively. We previously identified IDE as a principal regulator of Abeta levels in neuronal and Microglial cells. A small chromosomal region containing a mutant IDE allele has been associated with hyperinsulinemia and glucose intolerance in a rat model of DM2. Human genetic studies have implicated the IDE region of chromosome 10 in both AD and DM2. To establish whether IDE hypofunction decreases Abeta and insulin degradation in vivo and chronically increases their levels, we characterized mice with homozygous deletions of the IDE gene (IDE --). IDE deficiency resulted in a >50% decrease in Abeta degradation in both brain membrane fractions and primary neuronal cultures and a similar deficit in insulin degradation in liver. The IDE -- mice showed increased cerebral accumulation of endogenous Abeta, a hallmark of AD, and had hyperinsulinemia and glucose intolerance, hallmarks of DM2. Moreover, the mice had elevated levels of the intracellular signaling domain of the beta-amyloid precursor protein, which was recently found to be degraded by IDE in vitro. Together with emerging genetic evidence, our in vivo findings suggest that IDE hypofunction may underlie or contribute to some forms of AD and DM2 and provide a mechanism for the recently recognized association among hyperinsulinemia, diabetes, and AD

  13. Frampton M, Harvey RJ, Kirchner V (2003) Propentofylline for dementia. Cochrane.Database.Syst.Rev.CD002853
    Abstract: BACKGROUND: Propentofylline is a novel therapeutic agent for dementia that readily crosses the blood-brain barrier and acts by blocking the uptake of adenosine and inhibiting the enzyme phosphodiesterase. In vitro and in vivo its mechanism of action appears to be twofold; it inhibits the production of free radicals and reduces the activation of Microglial cells. It therefore interacts with the inflammatory processes that are thought to contribute to dementia, and given its mechanism of action is a possible disease modifying agent rather than a purely symptomatic treatment. OBJECTIVES: To determine the clinical efficacy and safety of propentofylline for people with dementia. SEARCH STRATEGY: The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 5 February 2003. Aventis, the manufacturing pharmaceutical company, was asked for data from unpublished studies but declined to enter into correspondence. SELECTION CRITERIA: Unconfounded double-blind randomized controlled trials of propentofylline compared with a placebo or another treatment group. DATA COLLECTION AND ANALYSIS: There were detailed reports of only four of the nine included studies. The efficacy of propentofylline was reviewed for undifferentiated dementia as there were not enough data to attempt a subgroup analysis for the types of dementia. MAIN RESULTS: The following statistically significant treatment effects in favour of propentofylline are reported. Cognition at 3, 6 and 12 months including MMSE at 12 months. [MD 1.2, 95%CI 0.12 to 2.28, P=0.03] Severity of dementia at 3, 6 and 12 months including CGI at 12 months [MD -0.21, 95%CI -0.39 to -0.03, P=0.03]. Activities of Daily Living (NAB) at 6 and 12 months [MD -1.20, 95%CI -2.22 to -0.18, P=0.02]. Global Assessment (CGI) at 3 months [MD -0.48, 95% CI -0.75 to -0.21, P=0.0006], but not at later times. Tolerability There were minimal data on adverse effects and drop-outs. There were a statistically significant treatment effects in favour of placebo at 12 months, for the number of dropouts, [OR=1.43, 95%CI 1.04 to 1.90, P=0.03]. REVIEWER'S CONCLUSIONS: There is limited evidence that propentofylline might benefit cognition, global function and activities of daily living of people with Alzheimer's disease and/or vascular dementia. The meta-analyses reported here are far from satisfactory as a summary of the efficacy of propentofylline, considering the unpublished information on another 1200 patients in randomized trials that exists. Unfortunately Aventis has been unwilling to correspond with the authors, significantly limiting the scope of this review

  14. Gomez-Tortosa E, Gonzalo I, Fanjul S, Sainz MJ, Cantarero S, Cemillan C, Yebenes JG, del Ser T (2003) Cerebrospinal fluid markers in dementia with lewy bodies compared with Alzheimer disease. Arch.Neurol. 60:1218-1222
    Abstract: BACKGROUND: Most patients with dementia with Lewy bodies (DLB) exhibit diffuse plaque-only pathology with rare neocortical neurofibrillary tangles (NFTs), as opposed to the widespread cortical neurofibrillary-tau involvement in Alzheimer disease (AD). Another pathological difference is the astrocytic and Microglial inflammatory responses, including release of interleukins (ILs), around the neuritic plaques and NFTs in AD brains that are absent or much lower in DLB. We analyzed cerebrospinal fluid (CSF) markers that reflect the pathological differences between AD and DLB. OBJECTIVE: To determine CSF concentrations of tau, beta-amyloid, IL-1beta, and IL-6 as potential diagnostic clues to distinguish between AD and DLB. METHODS: We measured total tau, beta-amyloid1-42, IL-1beta, and IL-6 levels in CSF samples of 33 patients with probable AD without parkinsonism, 25 patients with all the core features of DLB, and 46 age-matched controls. RESULTS: Patients with AD had significantly higher levels of tau protein than patients with DLB and controls (P<.001). The most efficient cutoff value provided 76% specificity to distinguish AD and DLB cases. Patients with AD and DLB had lower, but not significantly so, beta-amyloid levels than controls. The combination of tau and beta-amyloid levels provided the best sensitivity (84%) and specificity (79%) to differentiate AD vs controls but was worse than tau values alone in discriminating between AD and DLB. Beta-amyloid levels had the best correlation with disease progression in both AD and DLB (P =.01). There were no significant differences in IL-1beta levels among patients with AD, patients with DLB, and controls. Patients with AD and DLB showed slightly, but not significantly, higher IL-6 levels than controls. CONCLUSIONS: The tau levels in CSF may contribute to the clinical distinction between AD and DLB. Beta-amyloid CSF levels are similar in both dementia disorders and reflect disease progression better than tau levels. Interleukin CSF concentrations do not distinguish between AD and DLB

  15. Hartig W, Paulke BR, Varga C, Seeger J, Harkany T, Kacza J (2003) Electron microscopic analysis of nanoparticles delivering thioflavin-T after intrahippocampal injection in mouse: implications for targeting beta-amyloid in Alzheimer's disease. Neurosci.Lett. 338:174-176
    Abstract: Prevention of beta-amyloid (Abeta) production, aggregation and formation of Abeta deposits is a key pharmacological target in Alzheimer's disease. The passage of Abeta-binding compounds through the blood-brain barrier is often hampered for free ligands, whereas it is enhanced by drug encapsulation in nanoparticles. Here, we describe the preparation and characterization of polymeric carriers containing thioflavin-T as a marker for fibrillar Abeta. This study is then focused on electron microscopic analyses of thioflavin-T after injection of thioflavin-T-containing nanoparticles into the mouse hippocampus. Therefore, the photoconversion of fluorescent thioflavin-T as model drug was performed in tissues fixed 3 days post-injection. Thioflavin-T delivered from nanospheres was predominantly found in neurons and Microglia. Our data suggest that drugs delivered by nanoparticles might target Abeta in the brain

  16. Hartlage-Rubsamen M, Zeitschel U, Apelt J, Gartner U, Franke H, Stahl T, Gunther A, Schliebs R, Penkowa M, Bigl V, Rossner S (2003) Astrocytic expression of the Alzheimer's disease beta-secretase (BACE1) is stimulus-dependent. Glia 41:169-179
    Abstract: The beta-site APP-cleaving enzyme (BACE1) is a prerequisite for the generation of beta-amyloid peptides, which give rise to cerebrovascular and parenchymal beta-amyloid deposits in the brain of Alzheimer's disease patients. BACE1 is neuronally expressed in the brains of humans and experimental animals such as mice and rats. In addition, we have recently shown that BACE1 protein is expressed by reactive astrocytes in close proximity to beta-amyloid plaques in the brains of aged transgenic Tg2576 mice that overexpress human amyloid precursor protein carrying the double mutation K670N-M671L. To address the question whether astrocytic BACE1 expression is an event specifically triggered by beta-amyloid plaques or whether glial cell activation by other mechanisms also induces BACE1 expression, we used six different experimental strategies to activate brain glial cells acutely or chronically. Brain sections were processed for the expression of BACE1 and glial markers by double immunofluorescence labeling and evaluated by confocal laser scanning microscopy. There was no detectable expression of BACE1 protein by activated Microglial cells of the ameboid or ramified phenotype in any of the lesion paradigms studied. In contrast, BACE1 expression by reactive astrocytes was evident in chronic but not in acute models of gliosis. Additionally, we observed BACE1-immunoreactive astrocytes in proximity to beta-amyloid plaques in the brains of aged Tg2576 mice and Alzheimer's disease patients

  17. Holmes C, El Okl M, Williams AL, Cunningham C, Wilcockson D, Perry VH (2003) Systemic infection, interleukin 1beta, and cognitive decline in Alzheimer's disease. J.Neurol.Neurosurg.Psychiatry 74:788-789
    Abstract: Activated Microglia, the resident macrophages of the brain, are a feature of Alzheimer's disease. Animal models suggest that when activated Microglia are further activated by a subsequent systemic infection this results in significantly raised levels of interleukin 1beta within the CNS, which may in turn potentiate neurodegeneration. This prospective pilot study in Alzheimer's disease subjects showed that cognitive function can be impaired for at least two months after the resolution of a systemic infection and that cognitive impairment is preceded by raised serum levels of interleukin 1beta. These relations were not confounded by the presence of any subsequent systemic infection or by baseline cognitive scores. Further research is needed to determine whether recurrent systemic infections drive cognitive decline in Alzheimer's disease subjects through a cytokine mediated pathway

  18. Jayakumar R, Kusiak JW, Chrest FJ, Demehin AA, Murali J, Wersto RP, Nagababu E, Ravi L, Rifkind JM (2003) Red cell perturbations by amyloid beta-protein. Biochim.Biophys.Acta 1622:20-28
    Abstract: Amyloid beta-protein (A beta) accumulation in brain is thought to be important in causing the neuropathology of Alzheimer's disease (AD). A beta interactions with both neurons and Microglial cells play key roles in AD. Since vascular deposition of A beta is also implicated in AD, the interaction of red cells with these toxic aggregates gains importance. However, the effects of A beta interactions with red blood cells are less well understood. Synthetic amyloid beta-protein (1-40) was labeled with biotin and preincubated at 37 degrees C for 4, 14 and 72 h to produce fibrils. Flow cytometry was used to study the binding of these fibrils to red cells. The amyloid fibrils had a high affinity for the red cell with increased binding for the larger fibrils produced by longer preincubation. Bovine serum albumin (BSA) did not reverse the binding, but actually resulted in a more efficient binding of the A beta fibrils to the red cells. The interaction of A beta with red cells increased the mean cell volume and caused the cells to become more spherical. This effect was greater for the longer fibrils. At the same time the interaction of A beta with red cells produced an increase in their fluorescence measured after 16-h incubation at 37 degrees C. This increase in fluorescence is attributed to the formation of fluorescent heme degradation products. The effect of prior hemoglobin oxidation, catalase inhibition and glutathione peroxidase inhibition indicated that the amyloid-induced oxidative damage to the red cell involved hydrogen peroxide-induced heme degradation. These results suggest that amyloid interactions with the red cell may contribute to the pathology of AD

  19. Katsuse O, Iseki E, Kosaka K (2003) Immunohistochemical study of the expression of cytokines and nitric oxide synthases in brains of patients with dementia with Lewy bodies. Neuropathology. 23:9-15
    Abstract: Regional expression of cytokines (IL-1alpha, TNF-alpha), inducible nitric oxide synthase (iNOS) and neuronal NOS (nNOS) was immunohistochemically investigated in the brains of patients with dementia with Lewy bodies (DLB), compared with those of patients with Alzheimer's disease (AD) and non-demented elderly persons. It has been reported that inflammatory responses by cytokines and oxygen free radicals such as nitric oxide (NO) are associated with damaged neurons, degenerative neurites or amyloid deposits in AD brains. In the present study, overexpression of IL-1alpha, TNF-alpha and iNOS was demonstrated in the amygdala, hippocampus, entorhinal and insular cortices of DLB brains, which are pathologically the most vulnerable regions in DLB brains as well as AD brains. In addition, some Lewy body (LB)-bearing neurons were involved by the processes of IL-1alpha- and TNF-alpha-positive Microglia, and most extracellular LB were associated with the processes of TNF-alpha- and iNOS-positive astroglia. Glial involvement was also found around neuritic plaques and extracellular neurofibrillary tangles. In contrast, the expression of nNOS was reduced in the amygdala of DLB brains showing severe Lewy pathology. These findings suggest that cytokines and NO are significantly implicated in neuronal damage and death including LB formation in DLB brains

  20. Kitamura Y, Nomura Y (2003) Stress proteins and glial functions: possible therapeutic targets for neurodegenerative disorders. Pharmacol.Ther. 97:35-53
    Abstract: Recent findings suggest that unfolded or misfolded proteins participate in the pathology of several neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. Usually, several stress proteins and glial cells act as intracellular molecular chaperones and show chaperoning neuronal function, respectively. In the brains of patients with neurodegenerative disorders, however, stress proteins are expressed and frequently associated with protein aggregates, and glial cells are activated around degenerative regions. In addition, several stress proteins and glial cells may also regulate neuronal cell death and loss. Therefore, some types of stress proteins and glial cells are considered to be neuroprotective targets. We summarize the current findings regarding the neuroprotective effects of stress proteins and glial cells, and discuss the possibility of using this knowledge to develop new therapeutic strategies to treat neurodegeneration

  21. Lambert JC, Luedecking-Zimmer E, Merrot S, Hayes A, Thaker U, Desai P, Houzet A, Hermant X, Cottel D, Pritchard A, Iwatsubo T, Pasquier F, Frigard B, Conneally PM, Chartier-Harlin MC, DeKosky ST, Lendon C, Mann D, Kamboh MI, Amouyel P (2003) Association of 3'-UTR polymorphisms of the oxidised LDL receptor 1 (OLR1) gene with Alzheimer's disease. J.Med.Genet. 40:424-430
    Abstract: Although possession of the epsilon 4 allele of the apolipoprotein E gene appears to be an important biological marker for Alzheimer's disease (AD) susceptibility, strong evidence indicates that at least one additional risk gene exists on chromosome 12. Here, we describe an association of the 3'-UTR +1073 C/T polymorphism of the OLR1 (oxidised LDL receptor 1) on chromosome 12 with AD in French sporadic (589 cases and 663 controls) and American familial (230 affected sibs and 143 unaffected sibs) populations. The age and sex adjusted odds ratio between the CC+CT genotypes versus the TT genotypes was 1.56 (p=0.001) in the French sample and 1.92 (p=0.02) in the American sample. Furthermore, we have discovered a new T/A polymorphism two bases upstream of the +1073 C/T polymorphism. This +1071 T/A polymorphism was not associated with the disease, although it may weakly modulate the impact of the +1073 C/T polymorphism. Using 3'-UTR sequence probes, we have observed specific DNA protein binding with nuclear proteins from lymphocyte, astrocytoma, and neuroblastoma cell lines, but not from the Microglia cell line. This binding was modified by both the +1071 T/A and +1073 C/T polymorphisms. In addition, a trend was observed between the presence or absence of the +1073 C allele and the level of astrocytic activation in the brain of AD cases. However, Abeta(40), Abeta(42), Abeta total, and Tau loads or the level of Microglial cell activation were not modulated by the 3'-UTR OLR1 polymorphisms. Finally, we assessed the impact of these polymorphisms on the level of OLR1 expression in lymphocytes from AD cases compared with controls. The OLR1 expression was significantly lower in AD cases bearing the CC and CT genotypes compared with controls with the same genotypes. In conclusion, our data suggest that genetic variation in the OLR1 gene may modify the risk of AD

  22. Lesne S, Docagne F, Gabriel C, Liot G, Lahiri DK, Buee L, Plawinski L, Delacourte A, MacKenzie ET, Buisson A, Vivien D (2003) Transforming growth factor-beta 1 potentiates amyloid-beta generation in astrocytes and in transgenic mice. J.Biol.Chem. 278:18408-18418
    Abstract: Accumulation of the amyloid-beta peptide (Abeta) in the brain is crucial for development of Alzheimer's disease. Expression of transforming growth factor-beta1 (TGF-beta1), an immunosuppressive cytokine, has been correlated in vivo with Abeta accumulation in transgenic mice and recently with Abeta clearance by activated Microglia. Here, we demonstrate that TGF-beta1 drives the production of Abeta40/42 by astrocytes leading to Abeta production in TGF-beta1 transgenic mice. First, TGF-beta1 induces the overexpression of the amyloid precursor protein (APP) in astrocytes but not in neurons, involving a highly conserved TGF-beta1-responsive element in the 5'-untranslated region (+54/+74) of the APP promoter. Second, we demonstrated an increased release of soluble APP-beta which led to TGF-beta1-induced Abeta generation in both murine and human astrocytes. These results demonstrate that TGF-beta1 potentiates Abeta production in human astrocytes and may enhance the formation of plaques burden in the brain of Alzheimer's disease patients

  23. Lorenzl S, Albers DS, Relkin N, Ngyuen T, Hilgenberg SL, Chirichigno J, Cudkowicz ME, Beal MF (2003) Increased plasma levels of matrix metalloproteinase-9 in patients with Alzheimer's disease. Neurochem.Int. 43:191-196
    Abstract: Matrix metalloproteinases (MMPs) may play a role in the pathophysiology of Alzheimer's disease (AD). MMP-9 and tissue inhibitors of metalloproteinases (TIMPs) are elevated in postmortem brain tissue of AD patients. MMPs and TIMPs are found in neurons, Microglia, vascular endothelial cells and leukocytes. The aim of this study was to determine whether circulating levels of MMP-2, MMP-9, TIMP-1 and TIMP-2 are elevated in the plasma of AD patients. We compared AD patients to age- and gender-matched controls as well as to Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS) patients. There was constitutive expression of gelatinase A (MMP-2), and gelatinase B (MMP-9), in all the samples as shown by zymographic analysis. Levels of MMP-9 were significantly (P=0.003) elevated in the plasma of AD patients as compared to controls. Plasma levels of MMP-2, TIMP-1 and TIMP-2 were unchanged. There were no significant changes of MMP-2, MMP-9, TIMP-1 and TIMP-2 levels in PD and ALS samples. TIMP-1 and TIMP-2 were significantly correlated with MMP-9 in the AD patients. ApoE genotyping of plasma samples showed that levels of MMP-2, TIMP-1 and TIMP-2 and MMP-9 were not significantly different between the ApoE subgroups. These findings indicate that circulating levels of MMP-9 are increased in AD and may contribute to disease pathology

  24. Luca M, Chavez-Ross A, Edelstein-Keshet L, Mogilner A (2003) Chemotactic signaling, Microglia, and Alzheimer's disease senile plaques: is there a connection? Bull.Math.Biol. 65:693-730
    Abstract: Chemotactic cells known as Microglia are involved in the inflammation associated with pathology in Alzheimer's disease (AD). We investigate conditions that lead to aggregation of Microglia and formation of local accumulations of chemicals observed in AD senile plaques. We develop a model for chemotaxis in response to a combination of chemoattractant and chemorepellent signaling chemicals. Linear stability analysis and numerical simulations of the model predict that periodic patterns in cell and chemical distributions can evolve under local attraction, long-ranged repulsion, and other constraints on concentrations and diffusion coefficients of the chemotactic signals. Using biological parameters from the literature, we compare and discuss the applicability of this model to actual processes in AD

  25. Luth HJ, Apelt J, Ihunwo AO, Arendt T, Schliebs R (2003) Degeneration of beta-amyloid-associated cholinergic structures in transgenic APP SW mice. Brain Res. 977:16-22
    Abstract: Cholinergic dysfunction is a consistent feature of Alzheimer's disease, and the interrelationship between beta-amyloid deposits, inflammation and early cholinergic cell loss is still not fully understood. To characterize the mechanisms by which beta-amyloid and pro-inflammatory cytokines may exert specific degenerating actions on cholinergic cells ultrastructural investigations by electron microscopy were performed in brain sections from transgenic Tg2576 mice that express the Swedish double mutation of the human amyloid precursor protein and progressively develop beta-amyloid plaques during aging. Both light and electron microscopical investigations of the cerebral cortex of 19-month-old transgenic mice revealed a number of pathological tissue responses in close proximity of beta-amyloid plaques, such as activated Microglia, astroglial proliferation, increased number of fibrous astrocytes, brain edema, degeneration of nerve cells, dendrites and axon terminals. Ultrastructural detection of choline acetyl transferase (ChAT)-immunostaining in cerebral cortical sections of transgenic mice clearly demonstrated degeneration of ChAT-immunoreactive fibres in the environment of beta-amyloid plaques and activated glial cells suggesting a role of beta-amyloid and/or inflammation in specific degeneration of cholinergic synaptic structures

  26. McGeer EG, McGeer PL (2003) Inflammatory processes in Alzheimer's disease. Prog.Neuropsychopharmacol.Biol.Psychiatry 27:741-749
    Abstract: Neuroinflammation is a characteristic of pathologically affected tissue in several neurodegenerative disorders. These changes are particularly observed in affected brain areas of Alzheimer's disease (AD) cases. They include an accumulation of large numbers of activated Microglia and astrocytes as well as small numbers of T-cells, mostly adhering to postcapillary venules. Accompanying biochemical alterations include the appearance or up-regulation of numerous molecules characteristic of inflammation and free radical attack. Particularly important may be the complement proteins, acute phase reactants and inflammatory cytokines. These brain phenomena combined with epidemiological evidence of a protective effect of antiinflammatory agents suggest that such agents may have a role to play in treating the disease

  27. Melchor JP, Pawlak R, Strickland S (2003) The tissue plasminogen activator-plasminogen proteolytic cascade accelerates amyloid-beta (Abeta) degradation and inhibits Abeta-induced neurodegeneration. J.Neurosci. 23:8867-8871
    Abstract: Accumulation of the amyloid-beta (Abeta) peptide depends on both its generation and clearance. To better define clearance pathways, we have evaluated the role of the tissue plasminogen activator (tPA)-plasmin system in Abeta degradation in vivo. In two different mouse models of Alzheimer's disease, chronically elevated Abeta peptide in the brain correlates with the upregulation of plasminogen activator inhibitor-1 (PAI-1) and inhibition of the tPA-plasmin system. In addition, Abeta injected into the hippocampus of mice lacking either tPA or plasminogen persists, inducing PAI-1 expression and causing activation of Microglial cells and neuronal damage. Conversely, Abeta injected into wild-type mice is rapidly cleared and does not cause neuronal degeneration. Thus, the tPA-plasmin proteolytic cascade aids in the clearance of Abeta, and reduced activity of this system may contribute to the progression of Alzheimer's disease

  28. Minnasch P, Yamamoto Y, Ohkubo I, Nishi K (2003) Demonstration of puromycin-sensitive alanyl aminopeptidase in Alzheimer disease brain. Leg.Med.(Tokyo) 5 Suppl 1:S285-S287
    Abstract: Puromycin-sensitive alanyl aminopeptidase (PSA, EC 3.4.11.14) is a member of the ubiquitous aminopeptidase family, which cleaves N-terminal amino acids from proteins. PSA is suggested to function as a trimming protease in the MHC class I pathway, which is activated in brains of Alzheimer disease (AD). We examined the immunohistochemical localization of PSA in brains of AD and control cases using a rabbit anti-PSA. In the control cases, the antiserum revealed staining in a few glial cells and blood vessels. In AD brain, however, intensely stained cells were found richly in the cerebral cortex. Double immunofluorescence studies confirmed that PSA-positive cells were reactive Microglia. Such PSA-positive reactive Microglia tended to locate in and around senile plaques and were sometimes observed to associate with neurons containing neurofibillary tangles. The present result indicates that reactive Microglia express PSA-immunoreactive molecules, probably in association with the pathological conditions of AD

  29. Monsonego A, Weiner HL (2003) Immunotherapeutic approaches to Alzheimer's disease. Science 302:834-838
    Abstract: Although neurodegenerative diseases such as Alzheimer's disease are not classically considered mediated by inflammation or the immune system, in some instances the immune system may play an important role in the degenerative process. Furthermore, it has become clear that the immune system itself may have beneficial effects in nervous system diseases considered neurodegenerative. Immunotherapeutic approaches designed to induce a humoral immune response have recently been developed for the treatment of Alzheimer's disease. These studies have led to human trials that resulted in both beneficial and adverse effects. In animal models, it has also been shown that immunotherapy designed to induce a cellular immune response may be of benefit in central nervous system injury, although T cells may have either a beneficial or detrimental effect depending on the type of T cell response induced. These areas provide a new avenue for exploring immune system-based therapy of neurodegenerative diseases and will be discussed here with a primary focus on Alzheimer's disease. We will also discuss how these approaches affect Microglia activation, which plays a key role in therapy of such diseases

  30. Morgan D (2003) Antibody therapy for Alzheimer's disease. Expert.Rev.Vaccines. 2:53-59
    Abstract: The economic, social and emotional impact of Alzheimer's dementia is increasing dramatically as greater numbers live to advanced ages. The dearth of effective therapies has led to innovative approaches to treat the disease. This review summarizes the rationale, progress and setbacks regarding the use of antibody-based therapies to treat Alzheimer's disease and discusses future directions for this approach in Alzheimer's and other disorders

  31. Munch G, Gasic-Milenkovic J, Dukic-Stefanovic S, Kuhla B, Heinrich K, Riederer P, Huttunen HJ, Founds H, Sajithlal G (2003) Microglial activation induces cell death, inhibits neurite outgrowth and causes neurite retraction of differentiated neuroblastoma cells. Exp.Brain Res. 150:1-8
    Abstract: Activation of glial cells has been proposed to contribute to neuronal dysfunction and neuronal cell death in Alzheimer's disease. In this study, we attempt to determine some of the effects of secreted factors from activated murine N-11 Microglia on viability and morphology of neurons using the differentiated neuroblastoma cell line Neuro2a. Microglia were activated either by lipopolysaccharide (LPS), bacterial cell wall proteoglycans, or advanced glycation endproducts (AGEs), protein-bound sugar oxidation products. At high LPS or AGE concentrations, conditioned medium from Microglia caused neuronal cell death in a dose-dependent manner. At sublethal LPS or AGE concentrations, conditioned media inhibited retinoic acid-induced neurite outgrowth and stimulated retraction of already extended neurites. Among the many possible secreted factors, the contribution of NO or NO metabolites in the cytotoxicity of conditioned medium was investigated. Cell death and changes in neurite morphology were partly reduced when NO production was inhibited by nitric oxide synthase inhibitors. The results suggest that even in the absence of significant cell death, inflammatory processes, which are partly transmitted via NO metabolites, may affect intrinsic functions of neurons such as neurite extension that are essential components of neuronal morphology and thus may contribute to degenerative changes in Alzheimer's disease

  32. Murphy A, Sunohara JR, Sundaram M, Ridgway ND, McMaster CR, Cook HW, Byers DM (2003) Induction of protein kinase C substrates, Myristoylated alanine-rich C kinase substrate (MARCKS) and MARCKS-related protein (MRP), by amyloid beta-protein in mouse BV-2 Microglial cells. Neurosci.Lett. 347:9-12
    Abstract: Microglial activation by amyloid beta-protein in senile plaques contributes to neurodegeneration in Alzheimer disease. In BV-2 Microglial cells, amyloid beta-protein 1-40 (Abeta 1-40) elicited a dose-dependent increase (3-4 fold) of Myristoylated alanine-rich C kinase substrate (MARCKS) and MARCKS-related protein (MRP), two protein kinase C substrates implicated in membrane-cytoskeletal alterations underlying Microglial adhesion, migration, secretion, and phagocytosis. Neither MARCKS nor MRP was induced by the amyloid fragment Abeta 25-35, although both Abeta 1-40 and Abeta 25-35 caused extensive aggregation of BV-2 cells. Interferon-gamma synergistically enhanced the induction by Abeta 1-40 of inducible nitric oxide synthase, but not MARCKS or MRP. Our results suggest that MARCKS and MRP may play important roles in Microglia activated by amyloid peptides

  33. Nicoll JA, Wilkinson D, Holmes C, Steart P, Markham H, Weller RO (2003) Neuropathology of human Alzheimer disease after immunization with amyloid-beta peptide: a case report. Nat.Med. 9:448-452
    Abstract: Amyloid-beta peptide (Abeta) has a key role in the pathogenesis of Alzheimer disease (AD). Immunization with Abeta in a transgenic mouse model of AD reduces both age-related accumulation of Abeta in the brain and associated cognitive impairment. Here we present the first analysis of human neuropathology after immunization with Abeta (AN-1792). Comparison with unimmunized cases of AD (n = 7) revealed the following unusual features in the immunized case, despite diagnostic neuropathological features of AD: (i) there were extensive areas of neocortex with very few Abeta plaques; (ii) those areas of cortex that were devoid of Abeta plaques contained densities of tangles, neuropil threads and cerebral amyloid angiopathy (CAA) similar to unimmunized AD, but lacked plaque-associated dystrophic neurites and astrocyte clusters; (iii) in some regions devoid of plaques, Abeta-immunoreactivity was associated with Microglia; (iv) T-lymphocyte meningoencephalitis was present; and (v) cerebral white matter showed infiltration by macrophages. Findings (i)-(iii) strongly resemble the changes seen after Abeta immunotherapy in mouse models of AD and suggest that the immune response generated against the peptide elicited clearance of Abeta plaques in this patient. The T-lymphocyte meningoencephalitis is likely to correspond to the side effect seen in some other patients who received AN-1792 (refs. 7-9)

  34. Ophir G, Meilin S, Efrati M, Chapman J, Karussis D, Roses A, Michaelson DM (2003) Human apoE3 but not apoE4 rescues impaired astrocyte activation in apoE null mice. Neurobiol.Dis. 12:56-64
    Abstract: The allele E4 of apolipoprotein E (apoE) is an important risk factor for Alzheimer's disease (AD) and the chronic brain inflammation which is associated with AD is more pronounced in subjects who carry this allele. In the present study, we employed mice transgenic for the human apoE isoforms apoE3 or apoE4 on a null mouse apoE background and intracerebroventricular injection of LPS to investigate the possibility that the regulation of brain inflammation is affected by the apoE genotype. LPS treatment of control mice resulted in activation of brain astrocytes and Microglia whose extent decreased with age. LPS treatment of 6-month-old apoE transgenic and control mice resulted in marked activation of brain astrocytes in the control and apoE3 transgenic mice but had no effect on astrogliosis of age-matched apoE-deficient and apoE4 transgenic mice. In contrast, there were no significant differences between the levels of activated Microglia of the apoE3 and apoE4 transgenic mice following LPS treatment. Immunoblot assays revealed that the apoE4 and apoE3 transgenic mice had the same levels of brain apoE, which were similarly increased following LPS treatment. These results show that LPS-induced astrogliosis in apoE transgenic mice is regulated isoform-specifically by apoE3 and not by apoE4 and suggest that similar mechanisms may mediate the phenotypic expression of the apoE4 genotype in AD and in other neurodegenerative diseases

  35. Pahnke J, Walker LC, Schroeder E, Vogelgesang S, Stausske D, Walther R, Warzok RW (2003) Cerebral beta-amyloid deposition is augmented by the -491AA promoter polymorphism in non-demented elderly individuals bearing the apolipoprotein E epsilon4 allele. Acta Neuropathol.(Berl) 105:25-29
    Abstract: The apolipoprotein E epsilon4 allele (APOE, gene; apoE, protein) is widely accepted as a risk factor for Alzheimer's disease (AD). Our previous studies found that APOEepsilon4 promotes AD pathogenesis by fostering the early deposition of the amyloidogenic peptide Abeta in the aging brain. Recent reports suggest that polymorphisms in the upstream promoter region of APOE differentially affect the production of apoE and also may have an important influence on the probability of developing AD. In this study, we asked whether APOE promoter -491 (A/T) variants interact with APOE polymorphisms to modulate the degree of beta-amyloid- and tau-related pathology in the medial temporal lobe of the non-demented elderly. Our results confirm that APOEepsilon4 is associated with increased formation of senile plaques, cerebrovascular amyloid, and neurofibrillary tangles in the medial temporal lobe. We also found that homozygosity for A at position -491 of the APOE promoter (-491AA) correlates with increased Abeta17-24 and Abeta42 deposition in APOEepsilon4-positive cases, but not in cases lacking the epsilon4 allele. In comparison, Abeta burden is significantly less in epsilon4 carriers with the -491AT and -491TT promoter allelotypes. There was no effect of -491 polymorphisms on Abeta40 deposition (which is relatively sparse in the non-demented elderly), on the number of activated Microglia, or on the amount of neurofibrillary tangles. We conclude that the amyloidogenic effects of apoE4 are exacerbated by polymorphisms in the APOE promoter that enhance apoE production

  36. Parvathenani LK, Tertyshnikova S, Greco CR, Roberts SB, Robertson B, Posmantur R (2003) P2X7 mediates superoxide production in primary Microglia and is up-regulated in a transgenic mouse model of Alzheimer's disease. J.Biol.Chem. 278:13309-13317
    Abstract: Primary rat Microglia stimulated with either ATP or 2'- and 3'-O-(4-benzoylbenzoyl)-ATP (BzATP) release copious amounts of superoxide (O(2)(-)*). ATP and BzATP stimulate O(2)(-)* production through purinergic receptors, primarily the P2X(7) receptor. O(2)(-)* is produced through the activation of the NADPH oxidase. Although both p42/44 MAPK and p38 MAPK were activated rapidly in cells stimulated with BzATP, only pharmacological inhibition of p38 MAPK attenuated O(2)(-)* production. Furthermore, an inhibitor of phosphatidylinositol 3-kinase attenuated O(2)(-)* production to a greater extent than an inhibitor of p38 MAPK. Both ATP and BzATP stimulated Microglia-induced cortical cell death indicating this pathway may contribute to neurodegeneration. Consistent with this hypothesis, P2X(7) receptor was specifically up-regulated around beta-amyloid plaques in a mouse model of Alzheimer's disease (Tg2576)

  37. Qiu Z, Gruol DL (2003) Interleukin-6, beta-amyloid peptide and NMDA interactions in rat cortical neurons. J.Neuroimmunol. 139:51-57
    Abstract: Neuronal damage in Alzheimer's disease (AD) is thought to involve direct toxicity of beta-amyloid peptide (Abeta) and excitotoxicity involving NMDA receptors (NMDARs) and altered Ca(2+) dynamics. Inflammation agents produced by Microglia or astrocytes and associated with senile plaques such as the cytokine interleukin-6 (IL-6) could also contribute. To investigate this possibility, neuronal damage (lactate dehydrogenase assay, LDH, assay) was measured in cultures of rodent cortical neurons chronically treated with IL-6, Abeta or Abeta plus IL-6 and acutely treated with NMDA. Both Abeta and NMDA produced neuronal damage and this effect was larger with combined treatment. IL-6 did not produce significant neuronal damage but the largest neuronal damage was observed in cultures exposed to all three factors. IL-6 and Abeta enhanced Ca(2+) responses to NMDA and combined treatment produced the largest effect. These results are consistent with a role for interactions between Abeta, NMDA and IL-6 in the neuronal loss in AD

  38. Rangon CM, Haik S, Faucheux BA, Metz-Boutigue MH, Fierville F, Fuchs JP, Hauw JJ, Aunis D (2003) Different chromogranin immunoreactivity between prion and a-beta amyloid plaque. Neuroreport 14:755-758
    Abstract: Brain lesions in Creutzfeldt-Jakob disease (CJD) include spongiform change, neuronal loss, amyloid plaques, astrogliosis and Microglial activation. Microglia are thought to play a key role in prion-induced neurodegeneration. However, the intermediate molecules supporting relationships between neurons and Microglia are still unknown. Chromogranins (Cg) are soluble glycophosphoproteins that can activate Microglial cells leading to a neurotoxic phenotype. The immunoreactive patterns of CgA and CgB were investigated in CJD and compared to those observed in Alzheimer's disease. We found that CgB, but not CgA, immunoreactivity was selectively associated with prion protein deposits, whereas CgA was only seen in Abeta plaques. This suggests a specific influence of the constitutive amyloid protein on chromogranin secretion and a role of CgB in the CJD neurodegenerative process

  39. Scali C, Giovannini MG, Prosperi C, Bellucci A, Pepeu G, Casamenti F (2003) The selective cyclooxygenase-2 inhibitor rofecoxib suppresses brain inflammation and protects cholinergic neurons from excitotoxic degeneration in vivo. Neuroscience 117:909-919
    Abstract: Brain inflammatory processes underlie the pathogenesis of Alzheimer's disease, and non-steroidal anti-inflammatory drugs have a protective effect in the disease. The aim of this work was to study in vivo whether attenuation of brain inflammatory response to excitotoxic insult by the selective cyclooxygenase-2 inhibitor, rofecoxib, may prevent neurodegeneration, as a contribution to a better understanding of the role inflammation plays in the pathology of Alzheimer's disease. We investigated, by immunohistochemical methods, glia reaction, the activation of p38 mitogen-activated protein kinase (p38MAPK) pathway with an antibody selective for the phosphorylated form of the enzyme and the number of choline acetyltransferase-positive neurons and, by in vivo microdialysis, cortical extracellular levels of acetylcholine following the injection of quisqualic acid into the right nucleus basalis of adult rats. Seven days after injection, a marked reduction in the number of choline acetyltransferase-positive neurons was found, along with an intense glia reaction, selective activation of p38MAPK at the injection site and a significant decrease in the extracellular levels of acetylcholine in the cortex ipsilateral to the injection site. The loss of cholinergic neurons persisted for at least up to 28 days. Rofecoxib (3 mg/kg/day, starting 1 h prior to injection of quisqualic acid) treatment for 7 days significantly attenuated glia activation and prevented the loss of choline acetyltransferase-positive cells and a decrease in cortical acetylcholine release. The prevention of cholinergic cell loss by rofecoxib occurred concomitantly with the inhibition of p38MAPK phosphorylation. Our findings suggest an important role of brain inflammatory reaction in cholinergic degeneration and demonstrate a neuroprotective effect of rofecoxib, presumably mediated through the inhibition of p38MAPK phosphorylation

  40. Sheng JG, Bora SH, Xu G, Borchelt DR, Price DL, Koliatsos VE (2003) Lipopolysaccharide-induced-neuroinflammation increases intracellular accumulation of amyloid precursor protein and amyloid beta peptide in APPswe transgenic mice. Neurobiol.Dis. 14:133-145
    Abstract: The present study was designed to examine whether brain inflammation caused by systemic administration of lipopolysaccharides (LPS) alters the expression/processing of amyloid precursor protein (APP) and increases the generation of amyloid beta peptide (Abeta). APPswe transgenic (Tg) mice were treated with either LPS or phosphate-buffered saline (PBS). In LPS-treated APPswe mice, Abeta1-40/42 was 3-fold and APP was 1.8-fold higher than those in PBS-treated mice (P < 0.05) by ELISA, Western blots and immunoprecipitation-mass spectrometry (IP-MS) ProteinChip analysis. Numbers of Abeta- and APP-immunoreactive neurons (Abeta(+) and APP(+) neurons) increased significantly in LPS-treated APPswe mice; APP(+) and Abeta(+) neurons in neocortex were associated with an increased number of F4/80-immunoreactive Microglia (F4/80(+) Microglia) in their anatomical environment. Our findings demonstrate that experimental neuroinflammation increases APP expression/processing and causes intracellular accumulation of Abeta. It remains to be seen whether such events can cause neuronal dysfunction/degeneration and, with time, lead to extracellular Abeta deposits, as they occur in Alzheimer's disease

  41. Su Y, Ganea D, Peng X, Jonakait GM (2003) Galanin down-regulates Microglial tumor necrosis factor-alpha production by a post-transcriptional mechanism. J.Neuroimmunol. 134:52-60
    Abstract: The neuropeptide galanin (GAL) is up-regulated following neuronal axotomy or inflammation. Since other neuropeptides act as immunomodulatory agents, we sought to determine whether GAL might affect the murine Microglial cell line BV2, which expresses the GAL2 receptor. Even at very low concentrations, GAL inhibited tumor necrosis factor-alpha (TNF alpha) release but not TNF alpha mRNA levels in LPS-stimulated BV2 cells. Northern blot analysis showed that GAL inhibited the addition of a poly(A) tail, and stability assays showed that it also destabilized TNF alpha mRNA. Thus, GAL inhibits TNF alpha production by a post-transcriptional mechanism that both prevents the efficient addition of the poly(A) tail and accelerates TNF alpha mRNA degradation

  42. Takata K, Kitamura Y, Kakimura J, Shibagaki K, Tsuchiya D, Taniguchi T, Smith MA, Perry G, Shimohama S (2003) Role of high mobility group protein-1 (HMG1) in amyloid-beta homeostasis. Biochem.Biophys.Res.Commun. 301:699-703
    Abstract: In Alzheimer's disease (AD), fibrillar amyloid-beta (Abeta) peptides form senile plaques associated with activated Microglia. Recent studies have indicated that Microglial Abeta clearance is facilitated by several activators such as transforming growth factor-beta1 (TGF-beta1). The relationship between Microglia and Abeta formation and deposition is still unclear. In the present study, high mobility group protein-1 (HMG1) inhibited the Microglial uptake of Abeta (1-42) in the presence and absence of TGF-beta1. In addition, HMG1 bound to Abeta (1-42) and stabilized the oligomerization. In AD brains, protein levels of HMG1 were significantly increased in both the cytosolic and particulate fractions, and HMG1 and Abeta were colocalized in senile plaques associated with Microglia. These results suggest that HMG1 may regulate the homeostasis of extracellular Abeta (1-42) and Abeta oligomerization

  43. Thaker U, McDonagh AM, Iwatsubo T, Lendon CL, Pickering-Brown SM, Mann DM (2003) Tau load is associated with apolipoprotein E genotype and the amount of amyloid beta protein, Abeta40, in sporadic and familial Alzheimer's disease. Neuropathol.Appl.Neurobiol. 29:35-44
    Abstract: The total amount of hyperphosphorylated tau protein (p-tau load), present as neurofibrillary tangles (NFTs), neuropil threads or plaque neurites, was quantified in the frontal cortex of 109 cases of sporadic Alzheimer's disease (AD) and 35 cases of familial AD due to missense mutations in the presenilin-1, presenilin-2 and amyloid precursor protein genes. p-tau load was inversely correlated with age at onset of illness in both sporadic and familial AD but not with duration of disease. There was no difference in p-tau load between cases of familial AD and others with sporadic AD, matching the familial cases for apolipoprotein E (APO E) genotype. However, p-tau was greater in cases of familial and sporadic AD in the presence of APO E epsilon4 allele and increased with gene dose. Conversely, p-tau load tended to be lower when epsilon2 allele was present. In sporadic AD, tau load was highly significantly correlated with amyloid beta40 (Abeta40), but not Abeta42(43), load. These data indicate that the burden of pathological tau deposited in the brain in both familial and sporadic AD is favoured in the presence of APO E epsilon4 allele and also related to the amount of Abeta40, this also being higher when epsilon4 allele is present. Abeta40 plaques are rich in Microglial cells and it is possible that p-tau pathology in AD is triggered by reaction of Microglial cells to the presence of Abeta40 and not this peptide directly

  44. Uryu S, Tokuhiro S, Oda T (2003) beta-Amyloid-specific upregulation of stearoyl coenzyme A desaturase-1 in macrophages. Biochem.Biophys.Res.Commun. 303:302-305
    Abstract: beta-Amyloid peptide (A beta), a major component of senile plaques, the formation of which is characteristic of Alzheimer's disease (AD), is believed to induce inflammation of the brain mediated by Microglia, leading to neuronal cell loss. In this study, we performed an oligonucleotide microarray analysis to investigate the molecular events underlying the A beta-induced activation of macrophages and its specific suppression by the A beta-specific-macrophage-activation inhibitor, RS-1178. Of the approximately 36,000 genes and expressed sequence tags analyzed, eight genes were specifically and significantly upregulated by a treatment with interferon gamma (IFN gamma) and A beta compared to a treatment with IFN gamma alone (p<0.002). We found that the gene for a well-characterized lipogenetic enzyme, stearoyl coenzyme A desaturase-1 (SCD-1), was specifically upregulated by A beta treatment and was suppressed to basal levels by RS-1178. Although the underlying mechanisms remain unknown, our results suggest the presence of a link between AD and SCD-1

  45. Veerhuis R, Van Breemen MJ, Hoozemans JM, Morbin M, Ouladhadj J, Tagliavini F, Eikelenboom P (2003) Amyloid beta plaque-associated proteins C1q and SAP enhance the Abeta1-42 peptide-induced cytokine secretion by adult human Microglia in vitro. Acta Neuropathol.(Berl) 105:135-144
    Abstract: Pro-inflammatory cytokines released by activated Microglia could be a driving force in Alzheimer's disease (AD) pathology. We evaluated whether the presence of complement factor C1q and serum amyloid P component (SAP) in Abeta deposits is related to Microglial activation. Activated Microglia accumulate in SAP- and C1q-immunoreactive fibrillar amyloid beta (Abeta) plaques in AD temporal cortex. No clustered Microglia are seen in SAP- and C1q-positive circumscript, non-fibrillar, tau-negative Abeta plaques in AD caudate nucleus and non-demented control temporal cortex. In addition, no clustered Microglia were observed in C1q- and SAP-negative, irregular shaped, diffuse plaques in AD caudate nucleus and in non-demented control temporal cortex, which suggests that Microglia are attracted and activated in Abeta deposits of certain fibrillarity that, in addition, have fixed SAP and C1q. Therefore, the effects of Abeta(1-42), SAP and C1q on cytokine secretion by human postmortem Microglia in vitro were assessed. Abeta(1-42) alone had little to no effect. Abeta(1-42) peptides in combination with C1q or C1q and SAP increased Microglial interleukin (IL)-6 secretion four- and eightfold, respectively. Tumor necrosis factor (TNF)-alpha, as well as intracellular IL-1alpha and IL-1beta levels, also increased upon exposure of Microglia to Abeta(1-42)-SAP-C1q complexes. Combined with earlier findings, that amyloid and activated Microglia accumulate at a relatively early stage of cognitive decline in AD patients, this suggests that clustering of activated, cytokine-secreting Microglia in SAP- and C1q-containing Abeta deposits precedes neurodegenerative changes in AD, and thus may provide a "therapeutic window"

  46. Vehmas AK, Kawas CH, Stewart WF, Troncoso JC (2003) Immune reactive cells in senile plaques and cognitive decline in Alzheimer's disease. Neurobiol.Aging 24:321-331
    Abstract: We examined the associations of postmortem neocortical immunoreactivities for Microglia, astrocytes, Abeta and Tau with cognitive changes in clinically characterized subjects with pathological diagnoses (CERAD classification) of definite AD (9), possible AD (15) and age-matched controls (11). By measuring the fractional area (FA) of immunoreactivity, we found that Abeta deposits appear early in the pathogenesis of Abeta, but cannot account for cognitive decline. We found a significant increases in FA for Microglia in possible AD cases (nondemented) compared to controls (P<0.05) and in FA for astrocytes in definite AD (demented) compared to possible AD (P<0.01). Tau immunoreactivity was observed only in the neuropil of definite AD cases (P<0.001). The significant increase in Microglia between controls and AD possible cases suggests that activation of Microglia occurs in the early pathogenesis of AD, whereas the significant association between astrocytic reaction and dementia, suggests that these cells play a role in the late stage of the disease, when dementia develops. Tau immunoreactivity appears as the strongest morphological correlate of dementia

  47. Versijpt J, Van Laere K, Dierckx RA, Dumont F, De Deyn PP, Slegers G, Korf J (2003) Scintigraphic visualization of inflammation in neurodegenerative disorders. Nucl.Med.Commun. 24:209-221
    Abstract: In the past few decades, our understanding of the central nervous system has evolved from one of an immune-privileged site, to one where inflammation is pathognomonic for some of the most prevalent and tragic neurodegenerative diseases. Current research indicates that diseases as diverse as multiple sclerosis, stroke and Alzheimer's disease exhibit inflammatory processes that contribute to cellular dysfunction or loss. Inflammation, whether in the brain or periphery, is almost always a secondary response to a primary pathogen. In head trauma, for example, the blow to the head is the primary event. What typically concerns the neurologist and neurosurgeon more, however, is the secondary inflammatory response that will ensue and likely cause more neuron loss than the initial injury. This paper reviews the basic neuroinflammatory mechanisms, the potential neurotoxic mediators during activation of Microglia, the brain resident macrophages, and their role in neurodegeneration. Alzheimer's disease is taken as a prototype for exploring these mechanisms, as it expresses more than 40 inflammatory mediators, it is the most extensively studied disorder in terms of immune-related pathogenesis, and because of its importance as the most prevalent type of dementia. Tools for the visualization of these neuroinflammatory processes, both structural and mainly functional, are critically reviewed and discussed

  48. Versijpt JJ, Dumont F, Van Laere KJ, Decoo D, Santens P, Audenaert K, Achten E, Slegers G, Dierckx RA, Korf J (2003) Assessment of neuroinflammation and Microglial activation in Alzheimer's disease with radiolabelled PK11195 and single photon emission computed tomography. A pilot study. Eur.Neurol. 50:39-47
    Abstract: OBJECTIVES: Inflammation contributes to degeneration in Alzheimer's disease (AD), not simply as a secondary phenomenon, but primarily as a significant source of pathology. [(123)I]iodo-PK11195 is a single photon emission computed tomography (SPECT) ligand for the peripheral benzodiazepine receptor, the latter being expressed on Microglia (brain resident macrophages) and upregulated under inflammatory circumstances. The objectives were to assess AD inflammation by detecting [(123)I]iodo-PK11195 uptake changes and investigate how uptake values relate with perfusion SPECT and neuropsychological findings. METHODS: Ten AD and 9 control subjects were included. [(123)I]iodo-PK11195 SPECT images were realigned into stereotactic space where binding indices, normalized on cerebellar uptake, were calculated. RESULTS: The mean [(123)I]iodo-PK11195 uptake was increased in AD patients compared with controls in nearly all neocortical regions; however, statistical significance was only reached in the frontal and right mesotemporal regions. Significant correlations were found between regional increased [(123)I]iodo-PK11195 uptake and cognitive deficits. CONCLUSIONS: [(123)I]iodo-PK11195 is a cellular disease activity marker and allows in vivo assessment of Microglial inflammation in AD

  49. Watkins D (2003) Brain not inflamed? Alzheimer's may not be an inflammation after all. Sci.Am. 289:24-26

  50. Wegiel J, Imaki H, Wang KC, Wegiel J, Wronska A, Osuchowski M, Rubenstein R (2003) Origin and turnover of Microglial cells in fibrillar plaques of APPsw transgenic mice. Acta Neuropathol.(Berl) 105:393-402
    Abstract: Activated Microglial cells are an integral component of fibrillar plaques in brains of subjects with Alzheimer's disease (AD) and in brains of transgenic mice overexpressing amyloidogenic fragments of human amyloid precursor protein (APP). The aim of this ultrastructural study of fibrillar plaques was to characterize the origin of Microglial cells involved in cored plaque formation. Computer-aided three-dimensional reconstruction of plaques and microvessels in APPsw transgenic mice shows perivascular development of cored plaques. Perivascular location of almost all examined plaques and the infiltration at the interface between vessels and plaques with cells of monocyte/Microglia lineage indicates that plaques are formed by inflammatory cells of blood origin. The increase in the number of Microglial cells from 1 or 2 in an early plaque to more than 100 in a several-month-old plaque does not result in plaque degradation, but is associated with amyloid core growth and progression of neuronal degeneration, and suggests that recruitment of inflammatory cells of blood origin sustains plaque growth. Infiltration of the plaque with cells of blood origin and degeneration of 10-46% of inflammatory cells in large plaques, which is especially frequent at the interface between capillary wall and plaque, suggest their accelerated turnover

  51. White AR, Maher F, Brazier MW, Jobling MF, Thyer J, Stewart LR, Thompson A, Gibson R, Masters CL, Multhaup G, Beyreuther K, Barrow CJ, Collins SJ, Cappai R (2003) Diverse fibrillar peptides directly bind the Alzheimer's amyloid precursor protein and amyloid precursor-like protein 2 resulting in cellular accumulation. Brain Res. 966:231-244
    Abstract: The Alzheimer's disease Abeta peptide can increase the levels of cell-associated amyloid precursor protein (APP) in vitro. To determine the specificity of this response for Abeta and whether it is related to cytotoxicity, we tested a diverse range of fibrillar peptides including amyloid-beta (Abeta), the fibrillar prion peptides PrP106-126 and PrP178-193 and human islet-cell amylin. All these peptides increased the levels of APP and amyloid precursor-like protein 2 (APLP2) in primary cultures of astrocytes and neurons. Specificity was shown by a lack of change to amyloid precursor-like protein 1, tau-1 and cellular prion protein (PrP(c)) levels. APP and APLP2 levels were elevated only in cultures exposed to fibrillar peptides as assessed by electron microscopy and not in cultures treated with non-fibrillogenic peptide variants or aggregated lipoprotein. We found that PrP106-126 and the non-toxic but fibril-forming PrP178-193 increased APP levels in cultures derived from both wild-type and PrP(c)-deficient mice indicating that fibrillar peptides up-regulate APP through a non-cytotoxic mechanism and irrespective of parental protein expression. Fibrillar PrP106-126 and Abeta peptides bound recombinant APP and APLP2 suggesting the accumulation of these proteins was mediated by direct binding to the fibrillated peptide. This was supported by decreased APP accumulation following extensive washing of the cultures to remove fibrillar aggregates. Pre-incubation of fibrillar peptide with recombinant APP18-146, the putative fibril binding site, also abrogated the accumulation of APP. These findings show that diverse fibrillogenic peptides can induce accumulation of APP and APLP2 and this mechanism could contribute to pathogenesis in neurodegenerative disorders

  52. Wilcock DM, DiCarlo G, Henderson D, Jackson J, Clarke K, Ugen KE, Gordon MN, Morgan D (2003) Intracranially administered anti-Abeta antibodies reduce beta-amyloid deposition by mechanisms both independent of and associated with Microglial activation. J.Neurosci. 23:3745-3751
    Abstract: Active immunization against the beta-amyloid peptide (Alphabeta) with vaccines or passive immunization with systemic monoclonal anti-Abeta antibodies reduces amyloid deposition and improves cognition in APP transgenic mice. In this report, intracranial administration of anti-Alphabeta antibodies into frontal cortex and hippocampus of Tg2576 transgenic APP mice is described. The antibody injection resulted initially in a broad distribution of staining for the antibody, which diminished over 7 d. Although no loss of immunostaining for deposited Abeta was apparent at 4 hr, a dramatic reduction in the Alphabeta load was discernible at 24 hr and was maintained at 3 and 7 d. A reduction in the thioflavine-S-positive compact plaque load was delayed until 3 d, at which time Microglial activation also became apparent. At 1 week after the injection, Microglial activation returned to control levels, whereas Alphabeta and thioflavine-S staining remained reduced. The results from this study suggest a two-phase mechanism of anti-Alphabeta antibody action. The first phase occurs between 4 and 24 hr, clears primarily diffuse Alphabeta deposits, and is not associated with observable Microglial activation. The second phase occurs between 1 and 3 d, is responsible for clearance of compact amyloid deposits, and is associated with Microglial activation. The results are discussed in the context of other studies identifying coincident Microglial activation and amyloid removal in APP transgenic animals

  53. Yan Q, Zhang J, Liu H, Babu-Khan S, Vassar R, Biere AL, Citron M, Landreth G (2003) Anti-inflammatory drug therapy alters beta-amyloid processing and deposition in an animal model of Alzheimer's disease. J.Neurosci. 23:7504-7509
    Abstract: Alzheimer's disease (AD) is characterized by a Microglial-mediated inflammatory response elicited by extensive amyloid deposition in the brain. Nonsteroidal anti-inflammatory drug (NSAID) treatment reduces AD risk, slows disease progression, and reduces Microglial activation; however, the basis of these effects is unknown. We report that treatment of 11-month-old Tg2576 mice overexpressing human amyloid precursor protein (APP) with the NSAID ibuprofen for 16 weeks resulted in the dramatic and selective reduction of SDS-soluble beta-amyloid (Abeta)42, whereas it had smaller effects on SDS-soluble Abeta40 levels. Ibuprofen treatment resulted in 60% reduction of amyloid plaque load in the cortex of these animals. In vitro studies using APP-expressing 293 cells showed that ibuprofen directly affected APP processing, specifically reducing the production of Abeta42. Ibuprofen treatment resulted in a significant reduction in Microglial activation in the Tg2576 mice, as measured by CD45 and CD11b expression. NSAIDs activate the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARgamma); however, a potent agonist of this receptor, pioglitazone, only modestly reduced SDS-soluble Abeta levels and did not affect amyloid plaque burden or Microglia activation, indicating that PPARgamma activation is not involved in the Abeta lowering effect of NSAIDs. These data show that chronic NSAID treatment can reduce brain Abeta levels, amyloid plaque burden, and Microglial activation in an animal model of Alzheimer's disease

  54. Aisen PS (2002) The potential of anti-inflammatory drugs for the treatment of Alzheimer's disease. Lancet Neurol. 1:279-284
    Abstract: Genetic evidence suggests that generation of amyloid beta peptide is the pivotal step in the pathophysiology of Alzheimer's disease (AD). The mechanism by which this peptide induces neurodegeneration may involve inflammatory processes. Pharmacological suppression of inflammation may therefore ameliorate the neuropathology. Basic research studies provide substantial evidence that inflammatory processes present in the brains of patients with AD are destructive, and that anti-inflammatory drugs can provide protection. Furthermore, epidemiological studies suggest that anti-inflammatory drugs reduce the risk of AD. However, there is not yet any strong evidence from completed randomised controlled trials that anti-inflammatory treatment is beneficial. Large trials of glucocorticoid therapy, hydroxychloroquine, and non-steroidal anti-inflammatory drugs (NSAIDs) in the treatment of AD have so far been disappointing. Several studies, including a large primary prevention trial with NSAIDs, are still in progress. Major issues of selection of patients, drug regimen, and duration of treatment remain unresolved

  55. Ali-Khan Z (2002) Searching for an in vivo site for nascent amyloid fibril formation. J.Alzheimers.Dis. 4:105-114

  56. Apelt J, Lessig J, Schliebs R (2002) Beta-amyloid-associated expression of intercellular adhesion molecule-1 in brain cortical tissue of transgenic Tg2576 mice. Neurosci.Lett. 329:111-115
    Abstract: To study the relationship of beta-amyloid-mediated micro- and astrogliosis and inflammation-induced proteins including intercellular adhesion molecule (ICAM-1), brain tissue from transgenic Tg2576 mice expressing the Swedish mutation of the human amyloid precursor protein were examined for ICAM-1 expression. Immunocytochemistry demonstrated a diffuse immunostaining of ICAM-1 in the corona around fibrillary beta-amyloid plaques and an upregulation of ICAM-1 in activated Microglial cells located in close proximity to the plaques, an ICAM-1 distribution pattern that partly mimics the situation in the brain of Alzheimer patients. The developmental time course revealed that the rate of cortical ICAM-1 induction was somewhat behind that of the progression of beta-amyloid plaque deposition. The Microglial expression of ICAM-1 is a further indicator of the presence of inflammatory reactions in aged transgenic Tg2576 mouse brain, and may be a result of plaque-mediated astrocytic interleukin-1beta upregulation

  57. Arelin K, Kinoshita A, Whelan CM, Irizarry MC, Rebeck GW, Strickland DK, Hyman BT (2002) LRP and senile plaques in Alzheimer's disease: colocalization with apolipoprotein E and with activated astrocytes. Brain Res.Mol.Brain Res. 104:38-46
    Abstract: The low density lipoprotein receptor-related protein (LRP) is a multifunctional receptor which is present on senile plaques in Alzheimer's disease (AD). It is suggested to play an important role in the balance between amyloid beta (Abeta) synthesis and clearance mechanisms. One of its ligands, apolipoprotein E (apoE), is also present on senile plaques and has been implicated as a risk factor for AD, potentially affecting the deposition, fibrillogenesis and clearance of Abeta. Using immunohistochemistry we show that LRP was present only on cored, apoE-containing senile plaques, in both PDAPP transgenic mice and human AD brains. We detected strong LRP staining in neurons and in reactive astrocytes, and immunostaining of membrane-bound LRP showed colocalization with fine astrocytic processes surrounding senile plaques. LRP was not present in plaques in young transgenic mice or in plaques of APOE-knockout mice. As LRP ligands associated with Abeta deposits in AD brain may play an important role in inducing levels of LRP in both neurons and astrocytes, our findings support the idea that apoE might be involved in upregulation of LRP (present in fine astrocytic processes) and act as a local scaffolding protein for LRP and Abeta. The upregulation of LRP would allow increased clearance of LRP ligands as well as clearance of Abeta/ApoE complexes

  58. Bacskai BJ, Kajdasz ST, McLellan ME, Games D, Seubert P, Schenk D, Hyman BT (2002) Non-Fc-mediated mechanisms are involved in clearance of amyloid-beta in vivo by immunotherapy. J.Neurosci. 22:7873-7878
    Abstract: Transgenic (Tg) mouse models overexpressing amyloid precursor protein (APP) develop senile plaques similar to those found in Alzheimer's disease in an age-dependent manner. Recent reports demonstrated that immunotherapy is effective at preventing or removing amyloid-beta deposits in the mouse models. To characterize the mechanisms involved in clearance, we used antibodies of either IgG1 (10d5) or IgG2b (3d6) applied directly to the brains of 18-month-old Tg2576 or 20-month-old PDAPP mice. Both 10d5 and 3d6 led to clearance of 50% of diffuse amyloid deposits in both animal models within 3 d. Fc receptor-mediated clearance has been shown to be important in an ex vivo assay showing antibody-mediated clearance of plaques by Microglia. We now show, using in vivo multiphoton microscopy, that FITC-labeled F(ab')2 fragments of 3d6 (which lack the Fc region of the antibody) also led to clearance of 45% of the deposits within 3 d, similar to the results obtained with full-length 3d6 antibody. This result suggests that direct disruption of plaques, in addition to Fc-dependent phagocytosis, is involved in the antibody-mediated clearance of amyloid-beta deposits in vivo. Dense-core deposits that were not cleared were reduced in size by approximately 30% with full-length antibodies and F(ab')2 fragments 3 d after a topical treatment. Together, these results indicate that clearance of amyloid deposits in vivo may involve, in addition to Fc-dependent clearance, a non-Fc-mediated disruption of plaque structure

  59. Bamberger ME, Landreth GE (2002) Inflammation, apoptosis, and Alzheimer's disease. Neuroscientist. 8:276-283
    Abstract: The pathophysiology of Alzheimer's disease (AD) involves the deposition of amyloid in the brain and the extensive loss of neurons. The mechanisms subserving neuronal death in the disease remain unclear, although it has been postulated that this is due to apoptosis. There is compelling evidence that inflammatory processes play a role in disease progression and pathology. Amyloid plaque deposition is accompanied by the association of Microglia with the senile plaque, and this interaction stimulates these cells to undergo phenotypic activation and the subsequent elaboration of proinflammatory and neurotoxic products. This review focuses on the mechanisms by which neurons are lost in AD and the role Microglial proinflammatory products play in neuronal death

  60. Bi X, Gall CM, Zhou J, Lynch G (2002) Uptake and pathogenic effects of amyloid beta peptide 1-42 are enhanced by integrin antagonists and blocked by NMDA receptor antagonists. Neuroscience 112:827-840
    Abstract: Many synapses contain two types of receptors - integrins and N-methyl-D-aspartate (NMDA) receptors - that have been implicated in peptide internalization. The present studies tested if either class is involved in the uptake of the 42-residue form of amyloid beta peptide (Abeta1-42), an event hypothesized to be of importance in the development of Alzheimer's disease. Cultured hippocampal slices were exposed to Abeta1-42 for 6 days in the presence or absence of soluble Gly-Arg-Gly-Asp-Ser-Pro, a peptide antagonist of Arg-Gly-Asp (RGD)-binding integrins, or the disintegrin echistatin. Abeta uptake, as assessed with immunocytochemistry, occurred in 42% of the slices incubated with Abeta peptide alone but in more than 80% of the slices co-treated with integrin antagonists. Uptake was also found in a broader range of hippocampal subfields in RGD-treated slices. Increased sequestration was accompanied by two characteristics of early stage Alzheimer's disease: elevated concentrations of cathepsin D immunoreactivity and activation of Microglia. The selective NMDA receptor antagonist D-(-)-2-amino-5-phosphonovalerate completely blocked internalization of Abeta, up-regulation of cathepsin D, and activation of Microglia. Our results identify two classes of receptors that cooperatively regulate the internalization of Abeta1-42 and support the hypothesis that characteristic pathologies of Alzheimer's disease occur once critical intraneuronal Abeta concentrations are reached

  61. Bondolfi L, Calhoun M, Ermini F, Kuhn HG, Wiederhold KH, Walker L, Staufenbiel M, Jucker M (2002) Amyloid-associated neuron loss and gliogenesis in the neocortex of amyloid precursor protein transgenic mice. J.Neurosci. 22:515-522
    Abstract: APP23 transgenic mice express mutant human amyloid precursor protein and develop amyloid plaques predominantly in neocortex and hippocampus progressively with age, similar to Alzheimer's disease. We have previously reported neuron loss in the hippocampal CA1 region of 14- to 18-month-old APP23 mice. In contrast, no neuron loss was found in neocortex. In the present study we have reinvestigated neocortical neuron numbers in adult and aged APP23 mice. Surprisingly, results revealed that 8-month-old APP23 mice have 13 and 14% more neocortical neurons compared with 8-month-old wild-type and 27-month-old APP23 mice, respectively. In 27-month-old APP23 mice we found an inverse correlation between amyloid load and neuron number. These results suggest that APP23 mice have more neurons until they develop amyloid plaques but then lose neurons in the process of cerebral amyloidogenesis. Supporting this notion, we found more neurons with a necrotic-apoptotic phenotype in the neocortex of 24-month-old APP23 mice compared with age-matched wild-type mice. Stimulated by recent reports that demonstrated neurogenesis after targeted neuron death in the mouse neocortex, we have also examined neurogenesis in APP23 mice. Strikingly, we found a fourfold to sixfold increase in newly produced cells in 24-month-old APP23 mice compared with both age-matched wild-type mice and young APP23 transgenic mice. However, subsequent cellular phenotyping revealed that none of the newly generated cells in neocortex had a neuronal phenotype. The majority were Microglial and to a lesser extent astroglial cells. We conclude that cerebral amyloidosis in APP23 mice causes a modest neuron loss in neocortex and induces marked gliogenesis

  62. Brown CM, Wright E, Colton CA, Sullivan PM, Laskowitz DT, Vitek MP (2002) Apolipoprotein E isoform mediated regulation of nitric oxide release. Free Radic.Biol.Med. 32:1071-1075
    Abstract: Progressive dysfunction and death of neurons in Alzheimer's dementia is enhanced in patients carrying one or more APOE4 alleles who also display increased presence of oxidative stress markers. Modulation of oxidative stress is a nontraditional and physiologically relevant immunomodulatory function of apolipoprotein E (apoE). Stimulated peritoneal macrophages from APOE-transgenic replacement (APOE-TR) mice expressing only human apoE3 or human apoE4 protein isoforms were utilized as mouse models to investigate the role of apoE protein isoforms and gender in the regulation of oxidative stress. Macrophages from male APOE4/4-TR mice produced significantly higher levels of nitric oxide than from male APOE3/3-TR mice, while macrophages from female APOE3/3-TR and female APOE4/4-TR mice produced the similar levels of nitric oxide. Primary cultures of Microglial cells of APOE4 transgenic mice also produced significantly more nitric oxide than Microglia from APOE3 transgenic mice. These data suggest a potentially novel mechanism for gender-dependent and apoE isoform-dependent immune responses that parallel the genetic susceptibility of APOE4 carriers for the development of Alzheimer's disease

  63. Butterfield DA, Griffin S, Munch G, Pasinetti GM (2002) Amyloid beta-peptide and amyloid pathology are central to the oxidative stress and inflammatory cascades under which Alzheimer's disease brain exists. J.Alzheimers.Dis. 4:193-201
    Abstract: Alzheimer's disease (AD) brain is characterized by excess deposition of amyloid beta-peptide (Abeta), particularly the 42-amino acid peptide [Abeta(1-42)] and by extensive oxidative stress. Several sources of the oxidative stress and inflammatory cascades are likely, including that induced by advanced glycation end products, Microglial activation, and by Abeta(1-42) and its sequelae. This review briefly examines each of these sources of oxidative stress and inflammation in AD brain and discusses their potential roles in the clinical progression of AD dementia

  64. Calingasan NY, Erdely HA, Anthony AC (2002) Identification of CD40 ligand in Alzheimer's disease and in animal models of Alzheimer's disease and brain injury. Neurobiol.Aging 23:31-39
    Abstract: Chronic neuroinflammatory processes including glial activation may play a role in the pathogenesis of Alzheimer's disease (AD). The immune and inflammatory mediator CD40 ligand (CD40L) can augment the activation of cultured Microglia by amyloid beta-protein (Abeta) and promote neuron death. We investigated whether CD40L is increased in AD and in animal models of AD and neuroinflammation. In the frontal cortex of elderly, non-AD controls, CD40L immunoreactivity was found in the glial limiting membrane, astrocytes, and vascular profiles in gray and white matter. In AD, intense CD40L immunoreactivity occurred in hypertrophied astrocytes throughout the frontal cortex. The majority of CD40L-immunoreactive astrocytes in the gray matter occurred within, or at the periphery of, Abeta(1-42)-immunoreactive plaques. A semiquantitative analysis revealed a three-fold elevation in the number of CD40L-immunoreactive astrocytes in AD compared to controls. The cortex and hippocampus from 6 and 12 month-old amyloid precursor protein/presenilin 1 transgenic mice exhibited numerous neuritic plaques and CD40L-positive astrocytes, which were not detected in non-transgenic controls. In adult rats, little or no CD40L staining occurred in astrocytes of the intact brain, whereas intrastriatal excitotoxic or stab wound lesions produced a strong CD40L immunoreactivity that was more segregated than glial fibrillary acidic protein. These findings indicate that astrocytes are the predominant source of CD40L in brain, and are consistent with the proposed role of CD40L-mediated neurotoxic inflammation in AD

  65. Casal C, Serratosa J, Tusell JM (2002) Relationship between beta-AP peptide aggregation and Microglial activation. Brain Res. 928:76-84
    Abstract: We compared the relationship between the state of aggregation of two peptides (beta-AP 25-35 and beta-AP 1-42) and Microglial activation. After 7 days at 37 degrees C beta-AP 25-35 was in an amorphous state and did not activate Microglial cells. In the same conditions, aggregated beta-AP 1-42 activated these cells and caused changes in Microglial ramification, increasing the proliferation index and inducing tumor necrosis factor alpha (TNF alpha) release. Neither peptide induced a release of nitric oxide (NO). As the toxicity of beta-AP peptides in cell culture is associated with the formation of amyloid fibrils, we also examined the toxicity of both peptides in Microglial cell cultures and in PC 12 cell cultures. The results suggest that the two beta-AP fragments studied have similar neurotoxic effects but different pro-inflammatory activities

  66. Colton CA, Brown CM, Cook D, Needham LK, Xu Q, Czapiga M, Saunders AM, Schmechel DE, Rasheed K, Vitek MP (2002) APOE and the regulation of Microglial nitric oxide production: a link between genetic risk and oxidative stress. Neurobiol.Aging 23:777-785
    Abstract: The mechanism linking the APOE4 gene with increased susceptibility for Alzheimer's disease (AD) and poorer outcomes following closed head injury and stroke is unknown. One potential link is activation of the innate immune system in the CNS. Our previously published data demonstrated that apolipoprotein E regulates production of nitric oxide, a critical cytoactive factor released by immune active macrophages. To determine if immune regulation is different in the presence of apolipoprotein E4 compared to apolipoprotein E3, we have measured NO production by peritoneal and CNS macrophages (Microglia) cultured from transgenic mice that only express the human apoE4 or apoE3 protein isoform. Significantly more NO was produced in APOE4 mice compared to APOE3 transgenic mice that only express human apoE3 protein. Similarly, monocyte derived macrophages from humans carrying APOE4 gene alleles also produce significantly greater NO than those individuals with APOE3. The mechanism for this isoform-specific difference in NO production is not known and multiple sites in the NO production pathway may be affected. Expression of inducible nitric oxide synthase (iNOS) mRNA and protein are not significantly different between the APOE3 and APOE4 mice, suggesting that induction of iNOS is not a primary cause of the increased NO production in APOE4 animals. One alternative regulatory mechanism that demonstrates isoform specificity is arginine transport, which is greater in Microglia from APOE4 transgenic mice compared to Microglia from APOE3 mice. Increased transport is consistent with an increased production of NO and may reflect a direct or indirect effect of the APOE genotype on Microglial arginine uptake and Microglial activation in general. Overall, greater NO production in APOE4 carriers where characteristically high levels of oxidative/nitrosative stress are found in diseases such as AD provides a mechanism that potentially explains the genetic association between APOE4 and human diseases

  67. Colton CA, Brown CM, Czapiga M, Vitek MP (2002) Apolipoprotein-E allele-specific regulation of nitric oxide production. Ann.N.Y.Acad.Sci. 962:212-225
    Abstract: Cognitive decline and dementia are key features of Alzheimer's disease (AD) that result from failure of neuronal function. Affected neurons demonstrate indices of nitrosative stress resulting from changes in nitric oxide (NO) mediated redox balance. Neurofibrillary tangles, a characteristic neuropathologic feature of AD, and dysfunctional neurons frequently display 3-nitrotyrosine or other markers of nitrosative stress and immunoreactive nitric oxide synthase (NOS), suggesting that NOS-containing neurons are affected in AD. Our previous studies showed that apolipoprotein E treatment of macrophages increased NO production. Using transgenic mouse models expressing human apoE2, apoE3, or apoE4 protein isoforms and no mouse apoE, we now report an isoform specific difference in Microglial NO production. Mice expressing the apoE4 protein isoform have a greater NO production than mice expressing the apoE3 protein isoform. The supply of arginine, the sole substrate for NOS, is dependent on cationic amino acid transporters (CATs) that also demonstrate a similar pattern of apoE isoform dependency. Although arginine transport is greater in APOE4 Microglia, this effect is not limited to tissue macrophages. Cortical neurons in primary culture from APOE4 transgenic mice exhibit a similar increase in arginine uptake over neurons cultured from APOE3 mice. The inappropriate levels of arginine transport and of NO in the presence of the APOE4 compared to the APOE3 gene and its products are likely to have significant impact in the CNS

  68. Combarros O, Infante J, Llorca J, Pena N, Fernandez-Viadero C, Berciano J (2002) The myeloperoxidase gene in Alzheimer's disease: a case-control study and meta-analysis. Neurosci.Lett. 326:33-36
    Abstract: Myeloperoxidase (MPO) presence has been demonstrated in Microglia associated with senile plaques, and contributes to Alzheimer's disease (AD) pathology through oxidation-induced damage. Recently, a functional biallelic (G/A) polymorphism in the promotor region (-463) of the MPO gene has been associated with susceptibility to AD, but the reports of this association have been inconsistent. A case-control study utilizing a clinically well-defined group of 315 sporadic AD patients and 327 control subjects was performed to test this association. The current study does not demonstrate any significant difference in MPO genotype or allele frequencies between AD patients and controls. A meta-analysis of all studies available gave a non-significant (P=0.83) odds ratio of 1.02 for the MPO GG genotype. Our study in the Spanish population as well as the meta-analysis argue against the hypothesis that the MPO gene is causally related to AD

  69. Coraci IS, Husemann J, Berman JW, Hulette C, Dufour JH, Campanella GK, Luster AD, Silverstein SC, El Khoury JB (2002) CD36, a class B scavenger receptor, is expressed on Microglia in Alzheimer's disease brains and can mediate production of reactive oxygen species in response to beta-amyloid fibrils. Am.J.Pathol. 160:101-112
    Abstract: A pathological hallmark of Alzheimer's disease is the senile plaque, composed of beta-amyloid fibrils, Microglia, astrocytes, and dystrophic neurites. We reported previously that class A scavenger receptors mediate adhesion of Microglia and macrophages to beta-amyloid fibrils and oxidized low-density lipoprotein (oxLDL)-coated surfaces. We also showed that CD36, a class B scavenger receptor and an oxLDL receptor, promotes H(2)O(2) secretion by macrophages adherent to oxLDL-coated surfaces. Whether CD36 is expressed on Microglia, and whether it plays a role in secretion of H(2)O(2) by Microglia interacting with fibrillar beta-amyloid is not known. Using fluorescence-activated cell sorting analysis and immunohistochemistry, we found that CD36 is expressed on human fetal Microglia, and N9-immortalized mouse Microglia. We also found that CD36 is expressed on Microglia and on vascular endothelial cells in the brains of Alzheimer's disease patients. Bowes human melanoma cells, which normally do not express CD36, gained the ability to specifically bind to surfaces coated with fibrillar beta-amyloid when transfected with a cDNA encoding human CD36, suggesting that CD36 is a receptor for fibrillar beta-amyloid. Furthermore, two different monoclonal antibodies to CD36 inhibited H(2)O(2) production by N9 Microglia and human macrophages adherent to fibrillar beta-amyloid by approximately 50%. Our data identify a role for CD36 in fibrillar beta-amyloid-induced H(2)O(2) production by Microglia, and imply that CD36 can mediate binding to fibrillar beta-amyloid. We propose that similar to their role in the interaction of macrophages with oxLDL, class A scavenger receptors and CD36 play complimentary roles in the interactions of Microglia with fibrillar beta-amyloid

  70. Cui Y, Le Y, Yazawa H, Gong W, Wang JM (2002) Potential role of the formyl peptide receptor-like 1 (FPRL1) in inflammatory aspects of Alzheimer's disease. J.Leukoc.Biol. 72:628-635
    Abstract: Alzheimer's disease (AD) is a progressive, neurodegenerative disease characterized by the presence of multiple senile plaques in the brain tissue, which are also associated with considerable inflammatory infiltrates. Although the precise mechanisms of the pathogenesis of AD remain to be determined, the overproduction and precipitation of a 42 amino acid form of beta amyloid (Abeta(42)) in plaques have implicated Abeta in neurodegeneration and proinflammatory responses seen in the AD brain. Our recent studies revealed that the activation of formyl peptide receptor-like 1 (FPRL1), a seven-transmembrane, G-protein-coupled receptor, by Abeta(42) may be responsible for accumulation and activation of mononuclear phagocytes (monocytes and Microglia). We further found that upon binding FPRL1, Abeta(42) was rapidly internalized into the cytoplasmic compartment in the form of Abeta(42)/FPRL1 complexes. Persistent exposure of FPRL1-expressing cells to Abeta(42) resulted in intracellular retention of Abeta(42)/FPRL1 complexes and the formation of Congo-red-positive fibrils in mononuclear phagocytes. Our observations suggest that FPRL1 may not only mediate the proinflammatory activity of Abeta(42) but also actively participate in Abeta(42) uptake and the resultant fibrillar formation. Therefore, FPRL1 may constitute an additional molecular target for the development of therapeutic agents for AD

  71. Czlonkowska A, Kurkowska-Jastrzebska I (2002) [The role of inflammatory reaction in Alzheimer's disease and neurodegenerative processes]. Neurol.Neurochir.Pol. 36:15-23
    Abstract: Recent studies state that specific inflammatory mechanisms contribute to neurodegeneration. The theory is based on laboratory evidence of local upregulation of inflammatory cytokines (ex. IL-1, IL-6), acute phase proteins (ex. alpha 1-antitrypsin), activation of the complement cascade and accumulation of Microglia in damaged regions in AD. In addition epidemiologic studies suggest that anti-inflammatory treatment provides some protection from AD. The first trials with prednisone fail to show any positive influence in AD patients. The alternative therapies are now considered with nonsteroid anti-inflammatory drugs, colchicine, cyclophosphamide. The anti-inflammatory treatment gives hope for slowing progression of the disease and decline of AD incidence

  72. DeGiorgio LA, Manuelidis L, Bernstein JJ (2002) Transient appearance of amyloid precursor protein plaques in the brain of thymectomized rats after human leptomeningeal cell grafts. Neurosci.Lett. 322:62-66
    Abstract: Cells cultured from Alzheimer disease leptomeninges or skin were grafted into the cortex of adult thymectomized rats. At 3 days post-implant, plaque-like aggregates were found in the cortex, corpus callosum, septum and caudate nucleus. These structures were immunopositive for human amyloid precursor protein (APP), human amyloid beta peptide (Abeta), cathepsin D, apolipoprotein E and ubiquitin. Aberrant tau+ neurites, reactive astrocytes and Microglia were associated with many aggregates. Although birefringent amyloid occupied the central area of most aggregates, these structures had disappeared by l month post-implant. Abeta and APP produced by grafted non-neural human cells can penetrate rat brain and form plaque-like structures, which can be effectively cleared by the rat

  73. Eikelenboom P, Hoogendijk WJ, Jonker C, van Tilburg W (2002) Immunological mechanisms and the spectrum of psychiatric syndromes in Alzheimer's disease. J.Psychiatr.Res. 36:269-280
    Abstract: Pathological, genetic and epidemiological studies support the opinion that inflammatory mechanisms are involved in the pathogenesis of Alzheimer's disease (AD). Recent pathological and neuroradiological (PET) data show that activation of Microglia is an early pathogenic event that precedes the process of severe neuropil destruction in AD brains. In this paper we review the evidence that inflammatory mediators can play a pathogenic role in some behavioural disorders frequently encountered during the clinical course in AD patients. Motivational disturbances are the most striking of the depressive symptoms in AD and can be present in a preclinical stage of the disease. Experimental animal studies and clinical trials in humans have shown that cytokines can induce similar symptoms which were described as 'sickness behaviour' or 'depressive-like' state. Delirious states are frequently observed in more advanced stages of dementia. Delirium is generally considered the result of an imbalance in neurotransmitter systems with severe deficits of the cholinergic systems. Animal studies show that pro-inflammatory cytokines, such as interleukin-1, induce a reduced activity of the cholinergic system. In AD, the release of cytokines would exacerbate any already existing disturbances in the cholinergic neurotransmission. This could explain the susceptibility of demented patients to delirium provoked by a wide variety of trivial incidents that are accompanied by an acute phase response. The data reviewed in this paper suggest that it could be worthwhile employing a neuroimmunological approach to study at molecular level the pathogenesis of a broad spectrum of behavioural disturbances common in the clinical course of AD patients

  74. Eikelenboom P, Bate C, Van Gool WA, Hoozemans JJ, Rozemuller JM, Veerhuis R, Williams A (2002) Neuroinflammation in Alzheimer's disease and prion disease. Glia 40:232-239
    Abstract: Alzheimer's disease (AD) and prion disease are characterized neuropathologically by extracellular deposits of Abeta and PrP amyloid fibrils, respectively. In both disorders, these cerebral amyloid deposits are co-localized with a broad variety of inflammation-related proteins (complement factors, acute-phase protein, pro-inflammatory cytokines) and clusters of activated Microglia. The present data suggest that the cerebral Abeta and PrP deposits are closely associated with a locally induced, non-immune-mediated chronic inflammatory response. Epidemiological studies indicate that polymorphisms of certain cytokines and acute-phase proteins, which are associated with Abeta plaques, are genetic risk factors for AD. Transgenic mice studies have established the role of amyloid associated acute-phase proteins in Alzheimer amyloid formation. In contrast to AD, there is a lack of evidence that cytokines and acute-phase proteins can influence disease progression in prion disease. Clinicopathological and neuroradiological studies have shown that activation of Microglia is a relatively early pathogenetic event that precedes the process of neuropil destruction in AD patients. It has also been found that the onset of Microglial activation coincided in mouse models of prion disease with the earliest changes in neuronal morphology, many weeks before neuronal loss and subsequent clinical signs of disease. In the present work, we review the similarities and differences between the involvement of inflammatory mechanisms in AD and prion disease. We also discuss the concept that the demonstration of a chronic inflammatory-like process relatively early in the pathological cascade of both diseases suggests potential therapeutic strategies to prevent or to retard these chronic neurodegenerative disorders

  75. Fiala M, Liu QN, Sayre J, Pop V, Brahmandam V, Graves MC, Vinters HV (2002) Cyclooxygenase-2-positive macrophages infiltrate the Alzheimer's disease brain and damage the blood-brain barrier. Eur.J.Clin.Invest 32:360-371
    Abstract: BACKGROUND: Monocyte/macrophages are known to infiltrate the brain of patients with HIV-1 encephalitis (HIVE). In Alzheimer's disease brain, the origin of activated Microglia has not been determined. MATERIALS AND METHODS: We employed the antigen retrieval technique, immunocytochemistry, immunofluorescense, and confocal microscopy to identify macrophages and Microglia in relation to amyloid-beta plaques and the blood-brain barrier in autopsy brain tissues from patients with Alzheimer's disease (AD) and HIVE. RESULTS: In both conditions, cyclooxygenase-2 positive macrophages and, to a lesser degree, T and B cells infiltrate brain perivascular spaces and neuropil. The macrophages are distinguishable from ramified Microglia, and decorate the vessels at the sites of apparent of endothelial tight junction protein ZO-1 disruption. The macrophages also infiltrate amyloid-beta plaques, display intracellular amyloid-beta and are surrounded by amyloid-beta-free lacunae. Furthermore, the macrophages partially encircle the walls of amyloid-beta-containing vessels in amyloid angiopathy, and exhibit intracellular amyloid-beta but not paracellular lacunae. Significantly larger zones of fibrinogen leakage surround the microvessels in HIVE brain tissues compared with AD tissues (P = 0.034), and AD tissues have significantly greater leakage than control tissues (P = 0.0339). The AD group differs from a normal control age-matched group with respect to both the area occupied by CD68 (P = 0.03) and cyclooxygenase-2 immunoreactive cells (P = 0.004). CONCLUSION: In both HIVE and AD, blood-borne activated monocyte/macrophages and lymphocytes appear to migrate through a disrupted blood-brain barrier. The lacunae around macrophages in amyloid-beta plaques but not in vessel walls are consistent with the ability of macrophages to phagocytize and clear amyloid-beta deposits in vitro

  76. Giovannini MG, Scali C, Prosperi C, Bellucci A, Vannucchi MG, Rosi S, Pepeu G, Casamenti F (2002) Beta-amyloid-induced inflammation and cholinergic hypofunction in the rat brain in vivo: involvement of the p38MAPK pathway. Neurobiol.Dis. 11:257-274
    Abstract: Injection into the nucleus basalis of the rat of preaggregated Abeta(1-42) produced a congophylic deposit and Microglial and astrocyte activation and infiltration and caused a strong inflammatory reaction characterized by IL-1beta production, increased inducible cyclooxygenase (COX-2), and inducible nitric oxide synthase (iNOS) expression. Many phospho-p38MAPK-positive cells were observed around the deposit at 7 days after Abeta injection. Phospho-p38MAPK colocalized with activated Microglial cells, but not astrocytes. The inflammatory reaction was accompanied by cholinergic hypofunction. We investigated the protective effect of the selective COX-2 inhibitor rofecoxib in attenuating the inflammatory response and neurodegeneration evoked by Abeta(1-42). Rofecoxib (3 mg/kg/day, 7 days) reduced Microglia and astrocyte activation, iNOS induction, and p38MAPK activation to control levels. Cholinergic hypofunction was also significantly attenuated by treatment with rofecoxib. We show here for the first time in vivo the pivotal role played by the p38MAPK Microglial signal transduction pathway in the inflammatory response to the Abeta(1-42) deposit

  77. Giri R, Selvaraj S, Miller CA, Hofman F, Yan SD, Stern D, Zlokovic BV, Kalra VK (2002) Effect of endothelial cell polarity on beta-amyloid-induced migration of monocytes across normal and AD endothelium. Am.J.Physiol Cell Physiol 283:C895-C904
    Abstract: During normal aging and amyloid beta-peptide (Abeta) disorders such as Alzheimer's disease (AD), one finds increased deposition of Abeta and activated monocytes/Microglial cells in the brain. Our previous studies show that Abeta interaction with a monolayer of normal human brain microvascular endothelial cells results in increased adherence and transmigration of monocytes. Relatively little is known of the role of Abeta accumulated in the AD brain in mediating trafficking of peripheral blood monocytes (PBM) across the blood-brain barrier (BBB) and concomitant accumulation of monocytes/Microglia in the AD brain. In this study, we showed that interaction of Abeta(1--40) with apical surface of monolayer of brain endothelial cells (BEC), derived either from normal or AD individuals, resulted in increased transendothelial migration of monocytic cells (HL-60 and THP-1) and PBM. However, transmigration of monocytes across the BEC monolayer cultivated in a Transwell chamber was increased 2.5-fold when Abeta was added to the basolateral side of AD compared with normal individual BEC. The Abeta-induced transmigration of monocytes was inhibited in both normal and AD-BEC by antibodies to the putative Abeta receptor, receptor for advanced glycation end products (RAGE), and to the endothelial cell junction molecule, platelet-endothelial cell adhesion molecule-1 (PECAM-1). We conclude that interaction of Abeta with the basolateral surface of AD-BEC induces cellular signaling, promoting transmigration of monocytes from the apical to basolateral direction. We suggest that Abeta in the AD brain parenchyma or cerebrovasculature initiates cellular signaling that induces PBM to transmigrate across the BBB and accumulate in the brain

  78. Gordon MN, Holcomb LA, Jantzen PT, DiCarlo G, Wilcock D, Boyett KW, Connor K, Melachrino J, O'Callaghan JP, Morgan D (2002) Time course of the development of Alzheimer-like pathology in the doubly transgenic PS1+APP mouse. Exp.Neurol. 173:183-195
    Abstract: Doubly transgenic mice expressing both a mutated amyloid precursor protein and a mutated presenilin-1 protein accumulate A(beta) deposits as they age. The early A(beta) deposits were found to be primarily composed of fibrillar A(beta) and resembled compact amyloid plaques. As the mice aged, nonfibrillar A(beta) deposits increased in number and spread to regions not typically associated with amyloid plaques in Alzheimer's disease. The fibrillar, amyloid-containing deposits remained restricted to cortical and hippocampal structures and did not increase substantially beyond the 12-month time point. Even at early time points, the fibrillar deposits were associated with dystrophic neurites and activated astrocytes expressing elevated levels of glial fibrillary acidic protein. Microglia similarly demonstrated increased staining for complement receptor-3 in the vicinity of A(beta) deposits at early time points. However, when MHC-II staining was used to assess the degree of Microglial activation, full activation was not detected until mice were 12 months or older. Overall, the regional pattern of A(beta) staining resembles that found in Alzheimer disease; however, a progression from diffuse A(beta) to more compact amyloid deposits is not observed in the mouse model. It is noted that the activation of Microglia at 12 months is coincident with the apparent stabilization of fibrillar A(beta) deposits, raising the possibility that activated Microglia might clear fibrillar A(beta) deposits at a rate similar to their rate of formation, thereby establishing a relatively steady-state level of amyloid-containing deposits

  79. Griffin WS, Mrak RE (2002) Interleukin-1 in the genesis and progression of and risk for development of neuronal degeneration in Alzheimer's disease. J.Leukoc.Biol. 72:233-238
    Abstract: Interleukin-1 (IL-1), a key molecule in systemic immune responses in health and disease, has analogous roles in the brain where it may contribute to neuronal degeneration. Numerous findings suggest that this is the case. For example, IL-1 overexpression in the brain of Alzheimer patients relates directly to the development and progression of the cardinal neuropathological changes of Alzheimer's disease, i.e., the genesis and accumulation of beta-amyloid (Abeta) plaques and the formation and accumulation of neurofibrillary tangles in neurons, both of which contribute to neuronal dysfunction and demise. Several genetic studies show that inheritance of a specific IL-1A gene polymorphism increases risk for development of Alzheimer's disease by as much as sixfold. Moreover, this increased risk is associated with earlier age of onset of the disease. Homozygosity for this polymorphism in combination with another in the IL-1B gene further increases risk

  80. Guillemin GJ, Brew BJ (2002) Implications of the kynurenine pathway and quinolinic acid in Alzheimer's disease. Redox.Rep. 7:199-206
    Abstract: The kynurenine pathway (KP) is a major route of L-tryptophan catabolism leading to production of a number of biologically active molecules. Among them, the neurotoxin quinolinic acid (QUIN), is considered to be involved in the pathogenesis of a number of inflammatory neurological diseases. Alzheimer's disease is the major dementing disorder of the elderly that affects over 20 million peoples world-wide. Most of the approaches to explain the pathogenesis of Alzheimer's disease focus on the accumulation of amyloid beta peptide (A beta), in the form of insoluble deposits leading to formation of senile plaques, and on the formation of neurofibrillary tangles composed of hyperphosphorylated Tau protein. Accumulation of A beta is believed to be an early and critical step in the neuropathogenesis of Alzheimer's disease. There is now evidence for the KP being associated with Alzheimer's disease. Disturbances of the KP have already been described in Alzheimer's disease. Recently, we demonstrated that A beta 1-42, a cleavage product of amyloid precursor protein, induces production of QUIN, in neurotoxic concentrations, by macrophages and, more importantly, Microglia. Senile plaques in Alzheimer's disease are associated with evidence of chronic local inflammation (especially activated Microglia) A major aspect of QUIN toxicity is lipid peroxidation and markers of lipid peroxidation are found in Alzheimer's disease. Together, these data imply that QUIN may be one of the critical factors in the pathogenesis of neuronal damage in Alzheimer's disease. This review describes the multiple correlations between the KP and the neuropathogenesis of Alzheimer's disease and highlights more particularly the aspects of QUIN neurotoxicity, emphasizing its roles in lipid peroxidation and the amplification of the local inflammation

  81. Haas J, Storch-Hagenlocher B, Biessmann A, Wildemann B (2002) Inducible nitric oxide synthase and argininosuccinate synthetase: co-induction in brain tissue of patients with Alzheimer's dementia and following stimulation with beta-amyloid 1-42 in vitro. Neurosci.Lett. 322:121-125
    Abstract: In Alzheimer's disease (AD), amyloid plaques within the brain are surrounded by activated glial cells (Microglia and astrocytes). The mechanisms of glial activation and its effect on disease progression are not fully understood. Growing evidence suggests that beta-amyloid (Abeta) peptide, a major constituent of the amyloid plaque, is critically involved in the induction of an inflammatory response. The goal of this study was to examine the role of Abeta in the pathogenesis of local inflammation and neuronal cell death. We found increased mRNA levels of inducible nitric oxide synthase (iNOS) and the arginine regenerating enzyme argininosuccinate synthetase (ASS) within cortices of AD patients suggesting high output NO production. In vitro, synthetic Abeta1-42 and to a lesser extent Abeta1-40 induced iNOS and ASS transcription with consecutive NO overproduction in mixed rat neuronal-glial cultures. Furthermore, Abeta-stimulation lead to an increased release of inflammatory cytokines interleukin (IL)-1beta, IL-6 and tumor necrosis factor-alpha. Again, Abeta1-42 had a much more pronounced effect as compared to Abeta1-40. Our data suggest that Abeta1-42 is a key mediator of glial activation and via the induction of inflammatory mediators may be a critical component of the neurodegenerative process in AD

  82. Harman D (2002) Alzheimer's disease: role of aging in pathogenesis. Ann.N.Y.Acad.Sci. 959:384-395
    Abstract: Alzheimer's disease (AD) is characterized by intraneuronal fibrillary tangles, plaques, and cell loss. Brain lesions in both sporadic AD (SAD) and familial AD (FAD) are the same, and in the same distribution pattern, as those in individuals with Down syndrome (DS) and in smaller numbers in nondemented older individuals. Dementia onset is around 40 years for DS, 40-60 years for FAD, and usually over 60 years for SAD. The different categories of AD may be due to processes that augment to different degrees the innate cellular aging rate, that is, mitochondrial superoxide radical (SO) formation. Thus, they increase the rate of accumulation of AD lesions. This lowers the age of onset into the dementia ranges associated with DS, FAD, and SAD, and concomitantly shortens life spans. Faster aging lowers AD onset age by decreasing the onset age for neurofibrillary tangle formation and neuronal loss, and the age when brain intercellular H2O2 can activate Microglial cells. The early AD onset in DS is attributed to a defective mitochondrial complex 1. The proteins associated with FAD and their normal counterparts undergo proteolytic processing in the endoplasmic reticulum (ER). The mutated compounds increase the ratio of betaA42 to betaA40 and likely also down-regulate the ER calcium (Ca2+) buffering activity. Decreases in ER Ca2+ content should increase the mitochondrial Ca2+ pool, thus enhancing SO formation. SAD may be due to increased SO formation caused by mutations in the approximately 1000 genes involved in mitochondrial biogenesis and function. The hypothesis suggests measures to prevent and treat

  83. Hayes A, Thaker U, Iwatsubo T, Pickering-Brown SM, Mann DM (2002) Pathological relationships between Microglial cell activity and tau and amyloid beta protein in patients with Alzheimer's disease. Neurosci.Lett. 331:171-174
    Abstract: The extent of Microglial cell activation (Microglial cell load) was estimated by image analysis of ferritin-immunostained sections of frontal cortex from 72 patients with pathologically confirmed Alzheimer's disease (AD), and correlated with the amount of pathological tau and amyloid beta protein (Abeta), as both Abeta(40) and Abeta(42) load, in adjacent sections of the same cases. Microglial cell load did not correlate with either Abeta(40) or Abeta(42) load but was significantly correlated with pathological tau load. Microglial cell load was unrelated to age at onset of disease or duration of illness. It is possible that because the presence of Microglial cells predates that of pathological tau proteins within the cerebral cortex in AD, neurofibrillary damage to nerve cells may stem from the release of proinflammatory and other potentially neurotoxic molecules from Microglial cells

  84. Heneka MT, Galea E, Gavriluyk V, Dumitrescu-Ozimek L, Daeschner J, O'Banion MK, Weinberg G, Klockgether T, Feinstein DL (2002) Noradrenergic depletion potentiates beta -amyloid-induced cortical inflammation: implications for Alzheimer's disease. J.Neurosci. 22:2434-2442
    Abstract: Degeneration of locus ceruleus (LC) neurons and reduced levels of norepinephrine (NE) in LC projection areas are well known features of Alzheimer's disease (AD); however, the consequences of those losses are not clear. Because inflammatory mediators contribute to AD pathogenesis and because NE can suppress inflammatory gene expression, we tested whether LC loss influenced the brain inflammatory gene expression elicited by amyloid beta (Abeta). Adult rats were injected with the selective neurotoxin N-(2-chloroethyl)-N-ethyl-2 bromobenzylamine (DSP4) to induce LC death and subsequently injected in the cortex with Abeta (aggregated 1-42 peptide). DSP4 treatment potentiated the Abeta-dependent induction of inflammatory nitric oxide synthase (iNOS), interleukin (IL)-1beta, and IL-6 expression compared with control animals. In contrast, the induction of cyclooxygenase-2 expression was not modified by DSP4 treatment. In control animals, injection of Abeta induced iNOS primarily in Microglial cells, whereas in DSP4-treated animals, iNOS was localized to neurons, as is observed in AD brains. Injection of Abeta increased IL-1beta expression initially in Microglia and at later times in astrocytes, and expression levels were greater in DSP4-treated animals than in controls. The potentiating effects of DSP4 treatment on iNOS and IL-1beta expression were attenuated by coinjection with NE or the beta-adrenergic receptor agonist isoproterenol. These data demonstrate that LC loss and NE depletion augment inflammatory responses to Abeta and suggest that LC loss in AD is permissive for increased inflammation and neuronal cell death

  85. Hoozemans JJ, Veerhuis R, Janssen I, van Elk EJ, Rozemuller AJ, Eikelenboom P (2002) The role of cyclo-oxygenase 1 and 2 activity in prostaglandin E(2) secretion by cultured human adult Microglia: implications for Alzheimer's disease. Brain Res. 951:218-226
    Abstract: Microglial cyclo-oxygenase (COX) expression is considered to be important in the pathogenesis of Alzheimer's disease (AD) and, therefore, constitutes a key target for therapeutic intervention. We investigated the influence of AD plaque associated factors on COX-1 and COX-2 expression and activity in adult human Microglial cells in vitro. COX-2 immunoreactivity and mRNA were induced by lipopolysaccharide (LPS), not by AD plaque associated cytokines interleukin (IL)-1alpha, IL-1beta, IL-6, tumor necrosis factor (TNF)-alpha, or amyloid (A)beta(1-42). To assess functional COX activity, the release of PGE(2) into the culture medium was determined. LPS and also arachidonic acid (AA) dose-dependently stimulated PGE(2) release. The effects of AA are independent from induction of COX mRNA expression, or of de novo protein synthesis. No effects of either plaque-associated cytokines or Abeta(1-42) on PGE(2) secretion were seen, even when cells were co-stimulated with AA, to provide enough substrate. COX isotype selective inhibitors were used to discern relative contributions of COX-1 and COX-2 activities to Microglial PGE(2) secretion. COX-2 and in part COX-1-selective inhibitors inhibited LPS-induced PGE(2) secretion, whereas the AA-induced PGE(2) secretion was reduced by COX-1-selective inhibitors only. Apparently, adult human Microglia in vitro (1) constitutively express COX-1, and (2) do not express COX-2 upon exposure to either Abeta or plaque associated cytokines. In the light of Microglial COX activity as a potential therapeutical target in AD, the data presented in this study suggest that classical NSAIDs, rather than selective COX-2 inhibitors, are more potent in reducing Microglial prostaglandin secretion

  86. Hull M, Hampel H (2002) Neuroinflammation in Alzheimer's disease: potential targets for disease-modifying drugs. Ernst.Schering.Res.Found.Workshop159-178

  87. Hull M, Lieb K, Fiebich BL (2002) Pathways of inflammatory activation in Alzheimer's disease: potential targets for disease modifying drugs. Curr.Med.Chem. 9:83-88
    Abstract: In the human brain several cell types are capable of initiating and amplifying a brain specific inflammatory response involving the synthesis of cytokines, prostaglandins and oxygen free radicals. In Alzheimer's disease (AD), signs of an inflammatory activation of Microglia and astroglia are present inside and outside amyloid deposits. Cell culture and animal models suggest an interactive relationship between inflammatory activation, reduced neuronal functioning and deposition of amyloid. The activation of inflammation-associated enzymes such as p38 mitogen-activated protein kinase (p38 MAPK) and cycloxygenase-2 (COX-2) is not restricted to glial cells but also found in neurons and may contribute to intraneuronal damage. Epidemiological studies have shown a reduced risk of AD among users of anti-inflammatory drugs. Therefore, anti-inflammatory drugs have become the focus of several new treatment strategies. Small clinical trials with non-steroidal anti-inflammatory drugs (NSAIDs) such as indomethacin and diclofenac showed a trend for a disease modifying effect, while clinical trials with steroids did not show a beneficial effect. NSAIDs may not only act on COX-2 but also inhibit COX-1 activity or activate peroxisome proliferator-activated receptor gamma (PPAR gamma). Among promising new strategies to reduce the inflammatory activation in the CNS interfering with intracellular pro-inflammatory pathways has been shown to be effective in various cell culture and animal models. Inhibitors of p38MAPK and PPAR gamma agonists may be suitable agents to suppress inflammatory activation in AD

  88. Infante J, Llorca J, Berciano J, Combarros O (2002) No synergistic effect between -850 tumor necrosis factor-alpha promoter polymorphism and apolipoprotein E epsilon 4 allele in Alzheimer's disease. Neurosci.Lett. 328:71-73
    Abstract: In the brains of Alzheimer's disease (AD) patients, Microglia cells are activated and produce inflammatory mediators such as tumor necrosis factor-alpha (TNF-alpha). A recent study conducted in Northern Ireland showed that a polymorphism in the promotor region (-850) of the TNF-alpha gene increased the risk of AD associated with carriage of the apolipoprotein E (APOE) epsilon 4 allele. In a case-control study restricted to a population from Northern Spain and utilizing 321 sporadic AD patients and 312 control subjects, we have found that the -850 TNF-alpha polymorphism does not interact with the APOE gene to increase the risk associated with the epsilon 4 allele

  89. Iribarren P, Cui YH, Le Y, Wang JM (2002) The role of dendritic cells in neurodegenerative diseases. Arch.Immunol.Ther.Exp.(Warsz.) 50:187-196
    Abstract: Dendritic cells (DCs) are the most potent antigen-presenting cells (APCs) involved in the induction of adaptive immune responses. The presence of DCs in the central nervous system (CNS) and the active participation of the immune system in a variety of neurodegenerative diseases have been demonstrated. This review will discuss recent findings pertinent to DCs and other antigen-presenting cells in the CNS in health and disease states

  90. Jantzen PT, Connor KE, DiCarlo G, Wenk GL, Wallace JL, Rojiani AM, Coppola D, Morgan D, Gordon MN (2002) Microglial activation and beta -amyloid deposit reduction caused by a nitric oxide-releasing nonsteroidal anti-inflammatory drug in amyloid precursor protein plus presenilin-1 transgenic mice. J.Neurosci. 22:2246-2254
    Abstract: 3-4-(2-Fluoro-alpha-methyl-[1,1'-biphenyl]-4-acetyloxy)-3-methoxyphenyl]-2 -propenoic acid 4-nitrooxy butyl ester (NCX-2216), a nitric oxide (NO)-releasing derivative of the cyclooxygenase-1-preferring nonsteroidal anti-inflammatory drug (NSAID) flurbiprofen, dramatically reduced both beta-amyloid (Abeta) loads and Congo red staining in doubly transgenic (Tg) amyloid precursor protein plus presenilin-1 mice when administered at 375 ppm in diet between 7 and 12 months of age. This reduction was associated with a dramatic increase in the number of Microglia expressing major histocompatibility complex-II antigen, a marker for Microglial activation. In contrast, ibuprofen at 375 ppm in diet caused modest reductions in Abeta load but not Congo red staining, suggesting that the effects of this nonselective NSAID were restricted primarily to nonfibrillar deposits. We detected no effects of the cyclooxygenase-2-selective NSAID celecoxib at 175 ppm on amyloid deposition. In short-term studies of 12-month-old Tg mice, we found that the Microglia-activating properties of NCX-2216 (7.5 mg small middle dot kg(-1) small middle dot d(-1), s.c.) were present after 2 weeks of treatment. Microglia were not activated by NCX-2216 in non-Tg mice lacking Abeta deposits, nor were Microglia activated in Tg animals by flurbiprofen (5 mg small middle dot kg(-1) small middle dot d(-1)) alone. These data are consistent with the argument that activated Microglia can clear Abeta deposits. We conclude that the NO-generating component of NCX-2216 confers biological actions that go beyond those of typical NSAIDs. In conclusion, NCX-2216 is more efficacious than ibuprofen or celecoxib in clearing Abeta deposits from the brains of Tg mice, implying potential benefit in the treatment of Alzheimer's dementia

  91. Jordan-Sciutto KL, Malaiyandi LM, Bowser R (2002) Altered distribution of cell cycle transcriptional regulators during Alzheimer disease. J.Neuropathol.Exp.Neurol. 61:358-367
    Abstract: A number of mechanisms have been proposed to contribute to the selective neuronal cell loss observed during Alzheimer disease (AD). These include the formation and accumulation of amyloid-beta (Abeta)-containing plaques, neurofibrillary tangles (NFTs), and inflammatory processes mediated by astrocytes and Microglia. Neuronal responses to such insults in AD brain include increased protein levels and immunoreactivity for kinases known to regulate cell cycle progression. One down-stream target of these cell cycle regulatory proteins, the Retinoblastoma susceptibility gene product (pRb), has been shown to exhibit altered expression patterns in AD. Furthermore, in vitro studies have implicated pRb and one of the transcription factors it regulates, E2F1, in Abeta-induced cell death. To further explore the role of these proteins in AD, we examined the distribution of the E2F1 transcription factor and the hyperphosphorylated form of pRb (ppRb), which is unable to bind and regulate E2F activity, in the cortex of patients with AD and in non-demented controls. We observed increased ppRb and E2FI immunoreactivity in AD brain, with ppRb predominately located in the nucleus and E2F1 in the cytoplasm. Although neither of these proteins significantly co-localized with NFTs, both ppRb and E2F1 were found in cells surrounding a subset of Abeta-containing plaques. These results support a role for G1 to S phase cell cycle regulators in AD

  92. Kakimura J, Kitamura Y, Takata K, Umeki M, Suzuki S, Shibagaki K, Taniguchi T, Nomura Y, Gebicke-Haerter PJ, Smith MA, Perry G, Shimohama S (2002) Microglial activation and amyloid-beta clearance induced by exogenous heat-shock proteins. FASEB J. 16:601-603
    Abstract: Alzheimer's disease (AD) is characterized by the accumulation of fibrillar amyloid-beta (Abeta) peptides to form amyloid plaques. Understanding the balance of production and clearance of Abeta peptides is the key to elucidating amyloid plaque homeostasis. Microglia in the brain, associated with senile plaques, are likely to play a major role in maintaining this balance. Here, we show that heat-shock proteins (HSPs), such as HSP90, HSP70, and HSP32, induce the production of interleukin 6 and tumor necrosis factor alpha and increase the phagocytosis and clearance of Abeta peptides. This suggests that Microglial interaction with Abeta peptides is highly regulated by HSPs. The mechanism of Microglial activation by exogenous HSPs involves the nuclear factor kB and p38 mitogen-activated protein kinase pathways mediated by Toll-like receptor 4 activation. In AD brains, levels of HSP90 were increased in both the cytosolic and membranous fractions, and HSP90 was colocalized with amyloid plaques. These observations suggest that HSP-induced Microglial activation may serve a neuroprotective role by facilitating Abeta clearance and cytokine production

  93. Klegeris A, McGeer PL (2002) Cyclooxygenase and 5-lipoxygenase inhibitors protect against mononuclear phagocyte neurotoxicity. Neurobiol.Aging 23:787-794
    Abstract: Neuroinflammation and oxidative stress are believed to be contributing factors to neurodegeneration in normal aging, as well as in age-related neurological disorders. Reactive Microglia are found in increased numbers in aging brain and are prominently associated with lesions in such age-related degenerative conditions as Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). In vitro, stimulated Microglia or Microglial-like cells secrete neurotoxic materials and are generators of free radicals through their respiratory burst system. Agents that suppress Microglial activation are therefore candidates for neuroprotection. We have developed quantitative in vitro assays for measuring neurotoxicity of Microglia or other mononuclear phagocytes. Neuronal like SH-SY5Y cells are cultured in supernatants from activated cells of the human monocytic THP-1 line and their survival is followed. Respiratory burst is directly measured on the activated cells. We tested inhibitors of the cyclooxygenase (COX) or the 5-lipoxygenase (5-LOX) pathways as possible neuroprotective agents. The COX pathway generates inflammatory prostaglandins, while the 5-LOX pathway generates inflammatory leukotrienes. We found that inhibitors of both these pathways suppressed neurotoxicity in a dose-dependent fashion. They included the COX-1 inhibitor indomethacin; the COX-2 inhibitor NS-398; the mixed COX-1/COX-2 inhibitor ibuprofen; the nitric oxide (NO) derivatives of indomethacin, ibuprofen and flurbiprofen; the 5-LOX inhibitor REV 5901; and the 5-LOX activating protein (FLAP) inhibitor MK-886. The FLAP inhibitor also reduced respiratory burst activity in a more potent manner than indomethacin. Combinations of COX and 5-LOX inhibitors were more effective than single inhibitors. The data suggest that both COX inhibitors and 5-LOX inhibitors may be neuroprotective in vivo by suppressing toxic actions of Microglia/macrophages, and that combinations of the two might have greater therapeutic potential than single inhibitors of either class

  94. Koistinaho M, Kettunen MI, Goldsteins G, Keinanen R, Salminen A, Ort M, Bures J, Liu D, Kauppinen RA, Higgins LS, Koistinaho J (2002) Beta-amyloid precursor protein transgenic mice that harbor diffuse A beta deposits but do not form plaques show increased ischemic vulnerability: role of inflammation. Proc.Natl.Acad.Sci.U.S.A 99:1610-1615
    Abstract: beta-amyloid (A beta), derived form the beta-amyloid precursor protein (APP), is important for the pathogenesis of Alzheimer's disease (AD), which is characterized by progressive decline of cognitive functions, formation of A beta plaques and neurofibrillary tangles, and loss of neurons. However, introducing a human wild-type or mutant APP gene to rodent models of AD does not result in clear neurodegeneration, suggesting that contributory factors lowering the threshold of neuronal death may be present in AD. Because brain ischemia has recently been recognized to contribute to the pathogenesis of AD, we studied the effect of focal brain ischemia in 8- and 20-month-old mice overexpressing the 751-amino acid isoform of human APP. We found that APP751 mice have higher activity of p38 mitogen-activated protein kinase (p38 MAPK) in Microglia, the main immune effector cells within the brain, and increased vulnerability to brain ischemia when compared with age-matched wild-type mice. These characteristics are associated with enhanced Microglial activation and inflammation but not with altered regulation of cerebral blood flow, as assessed by MRI and laser Doppler flowmetry. Suppression of inflammation with aspirin or inhibition of p38 MAPK with a selective inhibitor, SD-282, abolishes the increased neuronal vulnerability in APP751 transgenic mice. SD-282 also suppresses the expression of inducible nitric-oxide synthase and the binding activity of activator protein 1. These findings elucidate molecular mechanisms of neuronal injury in AD and suggest that antiinflammatory compounds preventing activation of p38 MAPK in Microglia may reduce neuronal vulnerability in AD

  95. Kubo T, Nishimura S, Kumagae Y, Kaneko I (2002) In vivo conversion of racemized beta-amyloid ([D-Ser 26]A beta 1-40) to truncated and toxic fragments ([D-Ser 26]A beta 25-35/40) and fragment presence in the brains of Alzheimer's patients. J.Neurosci.Res. 70:474-483
    Abstract: The lag between beta-amyloid (A beta) deposition and neurodegeneration in Alzheimer's disease (AD) suggests that age-dependent factors are involved in the pathogenesis. Racemization of Ser and Asp in A beta is a typical age-dependent modification in AD. We have shown recently that A beta1-40 racemized at Ser(26) ([D-Ser(26)]A beta 1-40) is soluble and non-toxic to neuronal cells, but is easily converted by brain proteases to truncated toxic fragments, [D-Ser(26)]A beta 25-35/40. Furthermore, [D-Ser(26)]A beta1-40 in vivo, produced a drastic and synergistic neuronal loss by enhancing the excitotoxicity when co-injected into rat hippocampus with ibotenic acid, an excitatory amino acid, suggesting an in vivo conversion of non-toxic [D-Ser(26)]A beta1-40 to toxic fragments including [D-Ser(26)]A beta 25-35/40. In this study, we further investigated the mechanism behind the in vivo neuronal loss by [D-Ser(26)]A beta1-40 and ibotenic acid in rats, and also searched for the presence of [D-Ser(26)]A beta 25-35/40 antigens in AD brains. Quantitative analyses of the damaged area indicate clearly that non-toxic [D-Ser(26)]A beta 1-40 caused as much neurodegeneration as toxic [D-Ser(26)]A beta 25-35/40. MK-801, an NMDA receptor antagonist, completely inhibited the neurodegeneration. The immunohistochemical analyses using anti-[D-Ser(26)]A beta 25-35/40-specific antibodies demonstrated the presence of [D-Ser(26)]A beta 25-35/40 antigens in senile plaques and in degenerating hippocampal CA1 neurons in AD brains, but not in age-matched control brains. These results strengthen our hypothesis that soluble [D-Ser(26)]A beta1-40, possibly produced during aging, is released from plaques and converted by proteolysis to toxic [D-Ser(26)]A beta 25-35/40, which damage hippocampal CA1 neurons by enhancing excitotoxicity in AD. This may account for the lag between A beta deposition and neurodegeneration in AD

  96. Lee J, Chan SL, Mattson MP (2002) Adverse effect of a presenilin-1 mutation in Microglia results in enhanced nitric oxide and inflammatory cytokine responses to immune challenge in the brain. Neuromolecular.Med. 2:29-45
    Abstract: Inflammatory processes involving glial cell activation are associated with amyloid plaques and neurofibrillary tangles, the cardinal neuropathological lesions in the brains of Alzheimer's disease (AD) patients, However, it is unclear whether these inflammatory processes occur as a response to neuronal degeneration or might represent more seminal events in the disease process. Some cases of AD are caused by mutations in presenilin-1 (PS1), and it has been shown that PS1 mutations perturb neuronal calcium homeostasis, promote increased production of amyloid beta-peptide (Abeta), and render neurons vulnerable to synaptic dysfunction, excitotoxicity, and apoptosis. Although glial cells express PS1, it is not known if PS1 mutations alter glial cell functions. We now report on studies of glial cells in PS1 mutant knockin mice that demonstrate an adverse effect PS1 mutations in Microglial cells. Specifically, PS1 mutant mice exhibit an enhanced inflammatory cytokine response to immune challenge with bacterial lipopolysaccharide (LPS). LPS-induced levels of mRNAs encoding tumor necrosis fctor-alpha (TNFalpha), interleukin (IL)-1alpha, IL-1beta, IL-1 receptor antagonist, and IL-6 are significantly greater in the hippocampus and cerebral cortex of PS1 mutant mice as compared to wild-type mice. In contrast, the cytokine responses to LPS in the spleen is unaffected by the PS1 mutation. Studies of cultured Microglia from PS1 mutant and wild-type mice reveal that PS1 is expressed in Microglia and that the PS1 mutation confers a heightened sensitivity to LPS, as indicated by superinduction of inducible nitric oxide synthase (NOS) and activation of mitogen-activated protein kinase (MAPK). These findings demonstrate an adverse effect of PS1 mutations on Microglial cells that results in their hyperactivation under pro-inflammatory conditions, which may, together with direct effects of mutant PS1 in neurons, contribute to the neurodegenerative process in AD. These findings also have important implications for development of a "vaccine" for the prevention or treatment of AD

  97. Lee YB, Nagai A, Kim SU (2002) Cytokines, chemokines, and cytokine receptors in human Microglia. J.Neurosci.Res. 69:94-103
    Abstract: Enriched populations of human Microglial cells were isolated from mixed cell cultures prepared from embryonic human telencephalon tissues. Human Microglial cells exhibited cell type-specific antigens for macrophage-Microglia lineage cells including CD11b (Mac-1), CD68, B7-2 (CD86), HLA-ABC, HLA-DR and ricinus communis aggulutinin lectin-1 (RCA-1), and actively phagocytosed latex beads. Gene expression and protein production of cytokines, chemokines and cytokine/chemokine receptors were investigated in the purified populations of human Microglia. Normal unstimulated human Microglia expressed constitutively mRNA transcripts for interleukin- 1beta (IL-1beta) -6, -8, -10, -12, -15, tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, and monocyte chemoattractant protein-1 (MCP-1), while treatment with lipopolysaccharide (LPS) or amyloid beta peptides (Abeta) led to increased expression of mRNA levels of IL-8, IL-10, IL-12, TNF-alpha, MIP-1alpha, MIP-1beta, and MCP-1. Human Microglia, in addition, expressed mRNA transcripts for IL-1RI, IL-1RII, IL-5R, IL-6R, IL-8R, IL-9R, IL-10R, IL-12R, IL-13R, and IL-15R. Enzyme-linked immunosorbent assays (ELISA) showed increased protein levels in culture media of IL-1beta, IL-8, TNF-alpha, and MIP-1alpha in human Microglia following treatment with LPS or Abeta. Increased TNF-alpha release from human Microglia following LPS treatment was completely inhibited with IL-10 pretreatment, but not with IL-6, IL-9, IL-12, IL-13, or transforming growth factor-beta (TGF-beta). Present results should help in understanding the basic Microglial biology, but also the pathophysiology of activated Microglia in neurological diseases such as Alzheimer disease, Parkinson disease, Huntington disease, amyotrophic lateral sclerosis, stroke, and neurotrauma

  98. Lue LF, Walker DG (2002) Modeling Alzheimer's disease immune therapy mechanisms: interactions of human postmortem Microglia with antibody-opsonized amyloid beta peptide. J.Neurosci.Res. 70:599-610
    Abstract: The induction of an antibody response to amyloid beta (Abeta) peptide has become a strategy for the treatment of Alzheimer's disease (AD). This has proven effective in reducing the plaque burden in transgenic mice that develop Abeta plaques similar to human AD patients. The mechanism for enhanced clearance of Abeta is partly due to the interaction of immunoglobulin Fcgamma receptor-expressing Microglia and specific antibody-opsonized Abeta deposits. This interaction can stimulate Fcgamma receptor-mediated phagocytosis, but also results in inflammatory activation of these cells. Consequently, interaction of Microglia with antibody-antigen complexes could exacerbate the existing inflammation in the brains of AD patients. In this study, we used substrate-bound Abeta and cultured human Microglia from AD and non-demented cases to model interaction of Microglia and antibody-opsonized plaques in AD brains. Enhanced production of tumor necrosis factor-alpha, macrophage colony stimulating factor, interleukin-10, and superoxide ions was detected. We also demonstrated enhanced uptake of opsonized Abeta by Microglia, which was reduced significantly in the presence of excess IgG, indicative of the involvement of Fcgamma receptor-mediated mechanisms. Human Microglia were shown in this study to express mRNA for Fcgamma receptors I, IIa, IIb, and III. The expression of Fcgamma receptor II was augmented by proinflammatory stimulation. These results suggest that initial interactions of human Microglia with antibody-opsonized amyloid could result in increased inflammation. The consequence of this on inflammatory pathology in AD brains needs to be considered before immunization is used as a strategy for treating AD

  99. Mattson MP (2002) Oxidative stress, perturbed calcium homeostasis, and immune dysfunction in Alzheimer's disease. J.Neurovirol. 8:539-550
    Abstract: Although Alzheimer's disease (AD) may not involve a transmissible agent, it does involve a pathogenic process similar to that of transmissible prion disorders (both involve a protein that adopts an abnormal pathogenic conformation in which it self-aggregates, forming amyloid deposits in and surrounding neurons) and viral dementias such as human immunodeficiency virus (HIV) encephalitis. The clinical presentation of patients with AD is dominated by cognitive deficits and emotional disturbances that result from dysfunction and degeneration of neurons in the limbic system and cerebral cortex. The pathogenic process in the brain involves deposition of insoluble aggregates of amyloid beta-peptide, oxidative stress and calcium dysregulation in neurons, and activation of inflammatory cytokine cascades involving Microglia. However, AD patients also exhibit alterations in immune function. Studies of lymphocytes and lymphoblast cell lines from AD patients and age-matched normal control patients have documented alterations in cytokine and calcium signaling and increased levels of oxidative stress in immune cells from the AD patients. Studies of the pathogenic actions of mutations in presenilins and amyloid precursor protein that cause early-onset familial AD have established central roles for perturbed cellular calcium homeostasis and oxidative stress in the neurodegenerative process. Presenilin and amyloid precursor protein (APP) mutations also increase oxidative stress and perturb calcium signaling in lymphocytes in ways that alter their production of cytokines that are critical for proper immune responses. Immune dysfunction occurs prior to clinical symptoms in mouse models of AD, and brain cytokine responses to immune challenge are altered in presenilin mutant mice, suggesting a causal role for altered immune function in the disease process. Interestingly, immunization of AD mice with amyloid beta-peptide can stimulate the immune system to remove amyloid from the brain and can ameliorate memory deficits, suggesting that it may be possible to prevent AD by bolstering immune function

  100. McGeer PL, McGeer EG (2002) Local neuroinflammation and the progression of Alzheimer's disease. J.Neurovirol. 8:529-538
    Abstract: Postmortem immunohistochemical studies have revealed a state of chronic inflammation limited to lesioned areas of brain in Alzheimer's disease. Some key actors in this inflammation are activated Microglia (brain macrophages), proteins of the classical complement cascade, the pentraxins, cytokines, and chemokines. The inflammation does not involve the adaptive immune system or peripheral organs, but is rather due to the phylogenetically much older innate immune system, which appears to operate in most tissues of the body. Chronic inflammation can damage host tissue and the brain may be particularly vulnerable because of the postmitotic nature of neurons. Many of the inflammatory mediators have been shown to be locally produced and selectively elevated in affected regions of Alzheimer's brain. Moreover, studies of tissue in such degenerative processes as atherosclerosis and infarcted heart suggest a similar local innate immune reaction may be important in such conditions. Much epidemiological and limited clinical evidence suggests that nonsteroidal anti-inflammatory drugs may impede the onset and slow the progression of Alzheimer's disease. But these drugs strike at the periphery of the inflammatory reaction. Much better results might be obtained if drugs were found that could inhibit the activation of Microglia or the complement system in brain, and combinations of drugs aimed at different inflammatory targets might be much more effective than single agents

  101. McGeer PL, McGeer EG (2002) The possible role of complement activation in Alzheimer disease. Trends Mol.Med. 8:519-523
    Abstract: Molecular pathological studies of Alzheimer disease (AD) brain have revealed the presence of a spectrum of inflammatory mediators. Epidemiological studies have indicated that the use of anti-inflammatory agents, especially non-steroidal anti-inflammatory drugs (NSAIDs), results in a substantially reduced risk of contracting the disease. It is possible that well targeted anti-inflammatory agents will also be useful in treating established AD. Inhibitors of cyclooxygenase-2 have been unsuccessful in this regard, and traditional NSAIDs have produced mixed results. The complement system, which is strongly activated in AD brain, is an attractive target for therapeutic intervention, particularly through inhibition of the autodestructive action of the membrane attack complex. The complement system works in conjunction with activated Microglia, which express high levels of complement receptors. Overactive Microglia secrete many toxic materials. Inhibition of Microglial activation is another potential therapeutic target

  102. Miguel-Hidalgo JJ, Alvarez XA, Cacabelos R, Quack G (2002) Neuroprotection by memantine against neurodegeneration induced by beta-amyloid(1-40). Brain Res. 958:210-221
    Abstract: Progressive neuronal loss and cognitive decline in Alzheimer's disease (AD) might be aggravated by beta-amyloid-enhanced excitotoxicity. Memantine is an uncompetitive NMDA receptor antagonist under clinical development for the treatment of AD. Memantine has neuroprotective actions in several in vitro and in vivo models. In the present study, we determined whether memantine protected against beta-amyloid induced neurotoxicity and learning impairment in rats. Twenty Sprague-Dawley rats received vehicle or vehicle plus memantine (steady-state plasma concentrations of 2.34+/-0.23 microM, n=10) s.c. by osmotic pump for 9 days. After 2 days of treatment, 2 microl of water containing beta-amyloid 1-40 [Abeta(1-40)] were injected into the hippocampal fissure. On the ninth day of treatment, animals were sacrificed, and morphological and immunohistochemical techniques were used to determine the extent of neuronal degeneration and astrocytic and Microglial activation in the hippocampus. Psychomotor activity and spatial discrimination were tested on the eighth day of treatment. Abeta(1-40), but not water, injections into hippocampus led to neuronal loss in the CA1 subfield, evidence of widespread apoptosis, and astrocytic and Microglial activation and hypertrophy. Memantine treated animals had significant reductions in the amount of neuronal degeneration, pyknotic nuclei, and GFAP immunostaining as compared with vehicle treated animals. These data suggest that memantine, at therapeutically relevant concentrations, can protect against neuronal degeneration induced by beta-amyloid

  103. Minagar A, Shapshak P, Fujimura R, Ownby R, Heyes M, Eisdorfer C (2002) The role of macrophage/Microglia and astrocytes in the pathogenesis of three neurologic disorders: HIV-associated dementia, Alzheimer disease, and multiple sclerosis. J.Neurol.Sci. 202:13-23
    Abstract: Macrophage/Microglia (M phi) are the principal immune cells in the central nervous system (CNS) concomitant with inflammatory brain disease and play a significant role in the host defense against invading microorganisms. Astrocytes, as a significant component of the blood-brain barrier, behave as one of the immune effector cells in the CNS as well. However, both cell types may play a dual role, amplifying the effects of inflammation and mediating cellular damage as well as protecting the CNS. Interactions of the immune system, M phi, and astrocytes result in altered production of neurotoxins and neurotrophins by these cells. These effects alter the neuronal structure and function during pathogenesis of HIV-1-associated dementia (HAD), Alzheimer disease (AD), and multiple sclerosis (MS). HAD primarily involves subcortical gray matter, and both HAD and MS affect sub-cortical white matter. AD is a cortical disease. The process of M phi and astrocytes activation leading to neurotoxicity share similarities among the three diseases. Human Immunodeficiency Virus (HIV)-1-infected M phi are involved in the pathogenesis of HAD and produce toxic molecules including cytokines, chemokines, and nitric oxide (NO). In AD, M phis produce these molecules and are activated by beta-amyloid proteins and related oligopeptides. Demyelination in MS involves M phi that become lipid laden, spurred by several possible antigens. In these three diseases, cytokine/chemokine communications between M phi and astrocytes occur and are involved in the balance of protective and destructive actions by these cells. This review describes the role of M phi and astrocytes in the pathogenesis of these three progressive neurological diseases, examining both beneficent and deleterious effects in each disease

  104. Munch G, Robinson SR (2002) Potential neurotoxic inflammatory responses to Abeta vaccination in humans. J.Neural Transm. 109:1081-1087
    Abstract: Studies in transgenic mouse models of Alzheimer's disease suggested the development of a vaccine that would induce the production of antibodies against amyloid-beta (Abeta) peptide, which in turn would stimulate Microglia to phagocytose and remove senile plaques. However, some patients in the human clinical trials developed symptoms of brain inflammation, demonstrated by lymphocyte infiltration and elevated protein levels. These parameters are indicative of a breakdown of the blood-brain-barrier and entry of T-cells into the brain. Abeta-specific activated T-helper cells have the potential to amplify the existing pro-inflammatory conditions that are present in the brains of Alzheimer's disease patients. Cytotoxic T-cells might even attack the amyloid precursor protein which is present on the surface of many cells, including neurons. Before undertaking further vaccination trials there is a need to re-assess the risks associated with Abeta vaccination and with the therapeutic containment of a neuroinflammatory response. These risks may not be justified in the light of recent studies which have shown the efficacy of conventional, low-risk treatments in slowing the progress of AD

  105. Naidu A, Xu Q, Catalano R, Cordell B (2002) Secretion of apolipoprotein E by brain glia requires protein prenylation and is suppressed by statins. Brain Res. 958:100-111
    Abstract: Apolipoprotein E (ApoE) genotype modulates the risk of Alzheimer's disease. ApoE has been shown essential for amyloid beta-peptide fibrillogenesis and deposition, a defining pathological feature of this disease. Because astrocytes and Microglia represent the major source of extracellular apoE in brain, we investigated apoE secretion by glia. We determined that protein prenylation is required for apoE release from a continuous Microglial cell line, primary mixed glia, and from organotypic hippocampal cultures. Using selective protein prenylation inhibitors, apoE secretion was found to require protein geranylgeranylation. This prenylation involved a protein critical to apoE secretion, not apoE proper. ApoE secretion could also be suppressed by inhibiting synthesis of mevalonate, the precursor to both types of protein prenylation, using hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors (statins). Recent reports have described the beneficial effects of statins on the risk of dementia. Our finding that protein geranylgeranylation is required for apoE secretion in the brain parenchyma provides another contributing mechanism to explain the effective properties of statins against the development of dementia. In this model, statin-mediated inhibition of mevalonate synthesis, an essential reaction in forming geranylgeranyl lipid, would lower extracellular levels of parenchymal apoE. Because apoE has been found necessary for plaque development in transgenic models of Alzheimer's disease, suppressing apoE secretion by statins could reduce plaques and, in turn, improve cognitive function

  106. Nelson PT, Soma LA, Lavi E (2002) Microglia in diseases of the central nervous system. Ann.Med. 34:491-500
    Abstract: Microglia (MG) are enigmatic cells of the central nervous system (CNS). MG are morphologically, antigenically and functionally flexible, and have the potential for mobility and proliferation. MG are professional antigen-presenting cells and constitute part of the local CNS innate immune system, communicating with other immune cells via chemokines, cytokines and growth factors. MG contain several antigenic and functional markers similar to macrophages and dendritic cells (DCs), but also present several differences from DCs. The exact role(s) played by MG in the normal human CNS is the topic of lively debate. MG participate in many reactive processes in the CNS and are therefore an integral part of lesions in a variety of pathologic conditions. It is thought that MG may exacerbate diverse neurological conditions, including viral encephalitis, AIDS, Multiple Sclerosis (MS) and Alzheimer's disease. A recurrent theme is the perpetuation by MG of pathological cycles of monocyte recruitment, activation and cytopathic secretions, and/or auto antigen presentation

  107. Pocock JM, Liddle AC, Hooper C, Taylor DL, Davenport CM, Morgan SC (2002) Activated Microglia in Alzheimer's disease and stroke. Ernst.Schering.Res.Found.Workshop105-132

  108. Rogers J, Lue LF, Walker DG, Yan SD, Stern D, Strohmeyer R, Kovelowski CJ (2002) Elucidating molecular mechanisms of Alzheimer's disease in Microglial cultures. Ernst.Schering.Res.Found.Workshop25-44

  109. Rogers J, Strohmeyer R, Kovelowski CJ, Li R (2002) Microglia and inflammatory mechanisms in the clearance of amyloid beta peptide. Glia 40:260-269
    Abstract: There is now abundant evidence that brain Microglia, when activated, have the lineage, receptors, and synthetic capacity to participate in both potentially neurotoxic inflammatory responses and potentially beneficial phagocytic responses. Amyloid beta peptide (Abeta) forms highly insoluble, beta-pleated aggregates that are widely deposited in the Alzheimer's disease (AD) cortex and limbic system. Aggregated Abeta also activates the classical and alternative complement cascades. These properties make Abeta an excellent target for Microglial phagocytosis, a view supported by multiple reports, through well established mechanisms of phagocyte clearance

  110. Sai X, Kawamura Y, Kokame K, Yamaguchi H, Shiraishi H, Suzuki R, Suzuki T, Kawaichi M, Miyata T, Kitamura T, De Strooper B, Yanagisawa K, Komano H (2002) Endoplasmic reticulum stress-inducible protein, Herp, enhances presenilin-mediated generation of amyloid beta-protein. J.Biol.Chem. 277:12915-12920
    Abstract: Presenilin (PS) is essential for the gamma-cleavage required for the generation of the C terminus of amyloid beta-protein (Abeta). However, the mechanism underlying PS-mediated gamma-cleavage remains unclear. We have identified Herp cDNA by our newly developed screening method for the isolation of cDNAs that increase the degree of gamma-cleavage. Herp was originally identified as a homocysteine-responsive protein, and its expression is up-regulated by endoplasmic reticulum stress. Herp is an endoplasmic reticulum-localized membrane protein that has a ubiquitin-like domain. Here, we report that a high expression of Herp in cells increases the level of Abeta generation, although not in PS-deficient cells. We found that Herp interacts with both PS1 and PS2. Thus, Herp regulates PS-mediated Abeta generation, possibly through its binding to PS. Immunohistochemical analysis of a normal human brain section with an anti-Herp antibody revealed the exclusive staining of neurons and vascular smooth muscle cells. Moreover, the antibody strongly stained activated Microglia in senile plaques in the brain of patients with Alzheimer disease. Taken together, Herp could be involved in Abeta accumulation, including the formation of senile plaques and vascular Abeta deposits

  111. Sasaki A, Shoji M, Harigaya Y, Kawarabayashi T, Ikeda M, Naito M, Matsubara E, Abe K, Nakazato Y (2002) Amyloid cored plaques in Tg2576 transgenic mice are characterized by giant plaques, slightly activated Microglia, and the lack of paired helical filament-typed, dystrophic neurites. Virchows Arch. 441:358-367
    Abstract: We examined the brains of Tg2576 transgenic mice carrying human amyloid precursor protein with the Swedish mutation and Alzheimer's disease (AD) by means of immunohistochemistry and electron microscopy to clarify the characteristics of amyloid-associated pathology in the transgenic mice. In 12- to 29-month-old Tg2576 mice, congophilic cored plaques in the neocortex and hippocampus were labeled by all of the Abeta1-, Abeta40- and 42-specific antibodies, as seen in the classical plaques in AD. However, large-sized (>50 micro m in core diameter) plaques were seen more frequently in the older mice (18-29 months) than in those with AD (approximately 20% vs 2% in total cored plaques), and Tg2576 mice contained giant plaques (>75 micro m in core diameter), which were almost never seen in the brain of those with AD. Neither thread-like structures nor peripheral coronas were observed in the cored plaques of the transgenic mice in the silver impregnations. Immunohistochemically, plaque-accompanied Microglia showed a slight enlargement of the cytoplasm with consistent labeling of Mac-1 and macrosialin (murine CD68), and with partial labeling of Ia antigen and macrophage-colony stimulating factor receptor. Ultrastructurally, the Microglia surrounding the extracellular amyloid fibrils in the large, cored plaques showed some organella with phagocytic activity, such as secondary lysosomal, dense bodies, but intracellular amyloid fibrils were not evident. Dystrophic neurites in the plaques of the transgenic mice contained many dense multilaminar bodies, but no paired helical filaments. Our results suggest that giant cored plaques without coronas or paired helical filament-typed, dystrophic neurites are characteristic in Tg2576 mice, and that plaque-associated Microglia in transgenic mice are activated to be in phagocytic function but not sufficient enough to digest extracellularly deposited amyloid fibrils

  112. Schenk DB, Yednock T (2002) The role of Microglia in Alzheimer's disease: friend or foe? Neurobiol.Aging 23:677-679

  113. Seiler N (2002) Ammonia and Alzheimer's disease. Neurochem.Int. 41:189-207
    Abstract: Alzheimer's disease (AD) is the most common age-related neurodegenerative disorder. Behavioural, cognitive and memory dysfunctions are characteristic symptoms of AD. The formation of amyloid plaques is currently considered as the key event of AD. Other histological hallmarks of the disease are the formation of fibrillary tangles, astrocytosis, and loss of certain neuronal systems in cortical areas of the brain. A great number of possible aetiologic and pathogenetic factors of AD have been published in the course of the last two decades. Among the toxic factors, which have been considered to contribute to the symptoms and progression of AD, ammonia deserves special interest for the following reasons: (a) Ammonia is formed in nearly all tissues and organs of the vertebrate organism; it is the most common endogenous neurotoxic compounds. Its effects on glutamatergic and GABAergic neuronal systems, the two prevailing neuronal systems of the cortical structures, are known for many years. (b) The impairment of ammonia detoxification invariably leads to severe pathology. Several symptoms and histologic aberrations of hepatic encephalopathy (HE), of which ammonia has been recognised as a pathogenetic factor, resemble those of AD. (c) The excessive formation of ammonia in the brains of AD patients has been demonstrated, and it has been shown that some AD patients exhibit elevated blood ammonia concentrations. (d) There is evidence for the involvement of aberrant lysosomal processing of beta-amyloid precursor protein (beta-APP) in the formation of amyloid deposits. Ammonia is the most important natural modulator of lysosomal protein processing. (e) Inflammatory processes and activation of Microglia are widely believed to be implicated in the pathology of AD. Ammonia is able to affect the characteristic functions of Microglia, such as endocytosis, and cytokine production. Based on these facts, an ammonia hypothesis of AD has first been suggested in 1993. In the present review old and new observations are discussed, which are in support of the notion that ammonia is a factor able to produce symptoms of AD and to affect the progression of the disease

  114. Shirabe T, Irie K, Uchida M (2002) Autopsy case of aluminum encephalopathy. Neuropathology. 22:206-210
    Abstract: We report the case of a 59-year-old female aluminum encephalopathy patient who had chronic renal failure and took 3.0 g hydroxy-aluminum gel per day for the control of serum phosphorus level during a 15-year period. Nine months before her death she developed disorientation, memory disturbance, emotional incontinence, general convulsions and consciousness disturbance. Neuropathologically, the brain showed nerve cell atrophy and mild loss with stromal spongiosis, proliferation of astrocytes and Microglia in the cerebral cortex, basal ganglia and thalamus. Some nerve cells were stained immunohistochemically by phosphorylated neurofilament, but apparent neurofibrillary tangles were not observed. Aluminum was detected in the nerve cells of the cerebral cortex by X-ray microanalysis. Despite the long-term intake of aluminum, there were no neuropathological findings of Alzheimer's disease. The findings in our case suggested that aluminum alone might not develop Alzheimer's disease

  115. Sinigaglia-Coimbra R, Cavalheiro EA, Coimbra CG (2002) Postischemic hyperthermia induces Alzheimer-like pathology in the rat brain. Acta Neuropathol.(Berl) 103:444-452
    Abstract: This study addresses the effects of induced hyperthermia on post-ischemic rat brain evaluated histologically and/or immunohistochemically after 7-day, 2-month or 6-month survival. Hyperthermia (38.5 degrees - 40 degrees C) maintained (by heating the cage environment to 34-35 degrees C) for two consecutive periods of 5 and 9 h timed, respectively, from 4- and 21-h recirculation following 10-min global ischemia (two-vessel occlusion + hypotension) induced chronic neuronal death that became apparent in the rat forebrain from 7-day to 2-month survival. Associated immunohistochemical findings after 2 or 6 months of recovery included: (1) complement activation (membrane attack complex formation); (2) generalized overexpression of ubiquitin in surviving forebrain neurons; (3) persistent activation of macrophages; (4) presence of gemistocytic astrocytes in the hippocampus; (5) maturation of amyloid plaques (identified by immunohistochemistry using anti-human beta-A4 primary antibody) in cerebral cortex; and (6) intracellular deposits identified by anti-human hyperphosphorylated tau protein antibodies. This novel non-transgenic, self-sustained model of neurodegeneration triggered by the association of two prevalent insults to the aging human brain (ischemia and hyperthermia) presents morphological features similar to those of Alzheimer's disease. This finding raises the possibility that febrile complications of acute brain injuries may similarly impair human cognitive function in the long run

  116. Streit WJ (2002) Microglia and the response to brain injury. Ernst.Schering.Res.Found.Workshop11-24

  117. Strohmeyer R, Ramirez M, Cole GJ, Mueller K, Rogers J (2002) Association of factor H of the alternative pathway of complement with agrin and complement receptor 3 in the Alzheimer's disease brain. J.Neuroimmunol. 131:135-146
    Abstract: Factor H, a regulatory protein of the alternative pathway of complement (APC), is present in amyloid-beta (Abeta) plaques in Alzheimer's disease (AD). Abeta plaques also contain significant amounts of heparan sulfate proteoglycans (HSPGs), such as agrin, as well as numerous activated Microglia expressing increased levels complement receptor 3 (CR3). Here, we show the colocalization of each of these molecules in the AD brain and the functional capacity for these molecules to bind to one another in vitro. We propose that CR3 receptors expressed by Microglia are used for ligand binding to factor H bound to HSPGs and Abeta in plaques in the AD brain

  118. Takata K, Kitamura Y, Kakimura J, Shibagaki K, Taniguchi T, Gebicke-Haerter PJ, Smith MA, Perry G, Shimohama S (2002) Possible protective mechanisms of heme oxygenase-1 in the brain. Ann.N.Y.Acad.Sci. 977:501-506

  119. Tan J, Town T, Mullan M (2002) CD40-CD40L interaction in Alzheimer's disease. Curr.Opin.Pharmacol. 2:445-451
    Abstract: Increasing evidence supports a role of the CD40 receptor-CD40 ligand (CD40-CD40L) interaction in the pathogenesis of Alzheimer's disease (AD). It has previously been shown that this dyad acts synergistically with the Alzheimer amyloid-beta peptide to promote Microglial activation. Reactive Microglia produce potentially neurotoxic substances such as tumor necrosis factor alpha and the reactive oxygen species nitric oxide, which can induce bystander neuronal injury at high levels. When a transgenic mouse model of AD is crossed with an animal deficient in CD40L, the resulting phenotype is deficient in the gliosis observed in a mouse model of AD in which CD40L is present. Additionally, these crossed animals have complete absence of AD-like neuronal Tau hyperphosphorylation, a marker of the preneuronal tangle pathology in AD patients. This suggests that the CD40-CD40L system is a critical enhancer of Microglial activation in an AD transgenic mouse model and that such activation is associated with an increase in a key indicator of neuronal stress. Conversely, the finding that reduced CD40-CD40L interaction is associated with reduced chronic microgliosis and Tau hyperphosphorylation supports the view that, in general, mechanisms that reduce microgliosis will be beneficial in AD

  120. Tan J, Town T, Crawford F, Mori T, DelleDonne A, Crescentini R, Obregon D, Flavell RA, Mullan MJ (2002) Role of CD40 ligand in amyloidosis in transgenic Alzheimer's mice. Nat.Neurosci. 5:1288-1293
    Abstract: We have shown that interaction of CD40 with CD40L enables Microglial activation in response to amyloid-beta peptide (Abeta), which is associated with Alzheimer's disease (AD)-like neuronal tau hyperphosphorylation in vivo. Here we report that transgenic mice overproducing Abeta, but deficient in CD40L, showed decreased astrocytosis and microgliosis associated with diminished Abeta levels and beta-amyloid plaque load. Furthermore, in the PSAPP transgenic mouse model of AD, a depleting antibody against CD40L caused marked attenuation of Abeta/beta-amyloid pathology, which was associated with decreased amyloidogenic processing of amyloid precursor protein (APP) and increased circulating levels of Abeta. Conversely, in neuroblastoma cells overexpressing wild-type human APP, the CD40-CD40L interaction resulted in amyloidogenic APP processing. These findings suggest several possible mechanisms underlying mitigation of AD pathology in response to CD40L depletion, and validate the CD40-CD40L interaction as a target for therapeutic intervention in AD

  121. Taylor DL, Diemel LT, Cuzner ML, Pocock JM (2002) Activation of group II metabotropic glutamate receptors underlies Microglial reactivity and neurotoxicity following stimulation with chromogranin A, a peptide up-regulated in Alzheimer's disease. J.Neurochem. 82:1179-1191
    Abstract: Regulation of Microglial reactivity and neurotoxicity is critical for neuroprotection in neurodegenerative diseases. Here we report that Microglia possess functional group II metabotropic glutamate receptors, expressing mRNA and receptor protein for mGlu2 and mGlu3, negatively coupled to adenylate cyclase. Two different agonists of these receptors were able to induce a neurotoxic Microglial phenotype which was attenuated by a specific antagonist. Chromogranin A, a secretory peptide expressed in amyloid plaques in Alzheimer's disease, activates Microglia to a reactive neurotoxic phenotype. Chromogranin A-induced Microglial activation and subsequent neurotoxicity may also involve an underlying stimulation of group II metabotropic glutamate receptors since their inhibition reduced chromogranin A-induced Microglial reactivity and neurotoxicity. These results show that selective inhibition of Microglial group II metabotropic glutamate receptors has a positive impact on neuronal survival, and may prove a therapeutic target in Alzheimer's disease

  122. Ujiie M, Dickstein DL, Jefferies WA (2002) p97 as a biomarker for Alzheimer disease. Front Biosci. 7:e42-e47
    Abstract: The search is ongoing for a reliable serum biomarker for AD. The level of iron is elevated in the brain of Alzheimer's disease (AD) patients. Our studies have demonstrated that the level of the iron transport protein, p97, is increased in the serum of AD patients but not in various control groups. These results have recently been confirmed by another laboratory who extended our findings by demonstrating that p97 is not elevated in other neurodegenerative diseases. This qualifies p97 as a potentially powerful biomarker specific for AD. Although the relationship between increased level of iron and p97 in the AD brain is not well understood, our research supports the hypothesis that p97 over-expressed by senile plaque associated reactive Microglia is exocytosed and appears in blood. The relationship between elevated levels of serum p97 and AD, together with the possible future clinical application of p97 are considered in this report

  123. Van Everbroeck B, Dewulf E, Pals P, Lubke U, Martin JJ, Cras P (2002) The role of cytokines, astrocytes, Microglia and apoptosis in Creutzfeldt-Jakob disease. Neurobiol.Aging 23:59-64
    Abstract: In order to investigate inflammation and apoptosis in Creutzfeldt-Jakob disease (CJD) patients, we analyzed astrocytes, Microglia and apoptotic neurons in brain and IL-1beta in cerebrospinal fluid (CSF). Our results showed increased numbers of astrocytes in CJD and increased numbers of Microglia and apoptotic neurons both in CJD and Alzheimer's disease (AD) as compared to controls. All these markers correlated (P < 0.001) with the severity of the neuropathological lesions. An increased IL-1beta concentration was found in AD and CJD CSF that correlated with the number of Microglia and which did not change in the disease course of CJD.In conclusion, apoptotic neurons in CJD correlates to the neuropathological lesions and are probably related to the presence of inflammatory cells and cytokines which are present during the whole CJD disease process

  124. Walker DG, Lue LF, Beach TG (2002) Increased expression of the urokinase plasminogen-activator receptor in amyloid beta peptide-treated human brain Microglia and in AD brains. Brain Res. 926:69-79
    Abstract: The urokinase plasminogen-activator receptor (uPAR) is involved in many processes in inflammation including the migration of inflammatory-associated cells to sites of tissue damage. This receptor, also designated as CD87, is induced in response to a range of stimuli and is a marker of macrophage activation. Its role in inflammatory responses of Microglia in Alzheimer's disease (AD) has not been previously investigated. In this study we demonstrate that uPAR mRNA and protein expression is induced following incubation of human post-mortem brain-derived Microglia with fibrillar amyloid beta (Abeta) peptide. This response was stronger with Abeta peptide than with other tested pro-inflammatory agents. Induction of uPAR surface expression by Microglia was inhibited by the antioxidant N-acetyl-cysteine, indicating that this gene may be induced as a result of oxidative stress-related mechanisms. The significance of these findings to AD was investigated. UPAR protein levels were significantly increased in human brain tissues from the hippocampus, superior frontal gyrus and inferior temporal gyrus of AD cases compared with similar tissues from non-demented cases. Increased uPAR expression was not demonstrated in AD cerebellum. Finally, increased uPAR immunoreactivity was demonstrated in activated Microglia in AD brain samples using two different antibodies to uPAR. These results provide a connection between the induction of oxidative stress in AD and Microglial activation, and establish a possible involvement of uPAR in AD pathogenesis

  125. Wierzba-Bobrowicz T, Gwiazda E, Kosno-Kruszewska E, Lewandowska E, Lechowicz W, Bertrand E, Szpak GM, Schmidt-Sidor B (2002) Morphological analysis of active Microglia--rod and ramified Microglia in human brains affected by some neurological diseases (SSPE, Alzheimer's disease and Wilson's disease). Folia Neuropathol. 40:125-131
    Abstract: The activation of Microglial cells in pathological conditions is manifested primarily by their proliferation, as well as by the occurrence of a new morphological form--rod Microglia. In the present study immunohistochemical identification of rod Microglial phenotype against ramified Microglia was performed on segments of 17 brains derived from 7 cases of encephalitis of viral aetiology (including 5 SSPE cases), 6 cases of Wilson's disease and 4 cases of Alzheimer's disease. Segments from frontal, temporal and occipital lobes, cerebellum and brainstem were subjected to histological, histochemical and immunohistochemical reactions. The presence of activated rod and ramified Microglia was observed in sections derived from all structures of the brains under study. Both morphological forms of activated Microglia reacted to antibodies: HLA II, CD68, HAM56 and lectin RCA-1. Expression of HLA II molecules was less intensive on the surface of Microglial rod cells. A positive reaction to PCNA antibody was mainly observed in rod/elongated/cylinder-shaped nuclei, which is a characteristic feature of rod Microglia. In the study material, the localisation of Microglial processes seemed to depend rather on the structural topography of the cell in the brain than on the nuclear shape of the activated Microglial cell. Our observations revealed a strong similarity between immunohistochemical phenotypes of both morphological forms of Microglia with the indication that rod Microglia is a first developmental form of activated Microglia

  126. Wyss-Coray T, Yan F, Lin AH, Lambris JD, Alexander JJ, Quigg RJ, Masliah E (2002) Prominent neurodegeneration and increased plaque formation in complement-inhibited Alzheimer's mice. Proc.Natl.Acad.Sci.U.S.A 99:10837-10842
    Abstract: Abnormal accumulation of beta-amyloid (Abeta) in Alzheimer's disease (AD) is associated with prominent brain inflammation. Whereas earlier studies concluded that this inflammation is detrimental, more recent animal data suggest that at least some inflammatory processes may be beneficial and promote Abeta clearance. Consistent with these observations, overproduction of transforming growth factor (TGF)-beta1 resulted in a vigorous Microglial activation that was accompanied by at least a 50% reduction in Abeta accumulation in human amyloid precursor protein (hAPP) transgenic mice. In a search for inflammatory mediators associated with this reduced pathology, we found that brain levels of C3, the central component of complement and a key inflammatory protein activated in AD, were markedly higher in hAPP/TGF-beta1 mice than in hAPP mice. To assess the importance of complement in the pathogenesis of AD-like disease in mice, we inhibited C3 activation by expressing soluble complement receptor-related protein y (sCrry), a complement inhibitor, in the brains of hAPP mice. Abeta deposition was 2- to 3-fold higher in 1-year-old hAPP/sCrry mice than in age-matched hAPP mice and was accompanied by a prominent accumulation of degenerating neurons. These results indicate that complement activation products can protect against Abeta-induced neurotoxicity and may reduce the accumulation or promote the clearance of amyloid and degenerating neurons. These findings provide evidence for a role of complement and innate immune responses in AD-like disease in mice and support the concept that certain inflammatory defense mechanisms in the brain may be beneficial in neurodegenerative disease

  127. Zatta P, Zambenedetti P, Stella MP, Licastro F (2002) Astrocytosis, microgliosis, metallothionein-I-II and amyloid expression in high cholesterol-fed rabbits. J.Alzheimers.Dis. 4:1-9
    Abstract: Cholesterol is considered a risk factor in vascular dementia as well as in Alzheimer's disease. Several biochemical, epidemiological and genetic aspects established a correlation between cholesterol concentration and Alzheimer's disease. Microglia activation, astrocytosis with metallothionein-I-II overexpression, amyloid beta intraneuronal accumulation and a rare formation of amyloid beta extracellular positive deposits were the major immunohistochemical features observed in the brain of high cholesterol-fed animals. The relevance on the cholesterol metabolism in Alzheimer's disease pathogenesis is also discussed

  128. Allison AC, Cacabelos R, Lombardi VR, Alvarez XA, Vigo C (2001) Celastrol, a potent antioxidant and anti-inflammatory drug, as a possible treatment for Alzheimer's disease. Prog.Neuropsychopharmacol.Biol.Psychiatry 25:1341-1357
    Abstract: In the brains of patients with Alzheimer's disease (AD) signs of neuronal degeneration are accompanied by markers of Microglial activation, inflammation, and oxidant damage. The presence of nitrotyrosine in the cell bodies of neurons in AD suggests that peroxynitrite contributes to the pathogenesis of the disease. A drug with antioxidant and anti-inflammatory activity may prevent neuronal degeneration in AD. Celastrol, a plant-derived triterpene, has these effects. In low nanomolar concentrations celastrol was found to suppress the production by human monocytes and macrophages of the pro-inflammatory cytokines TNF-alpha and IL-1beta. Celastrol also decreased the induced expression of class II MHC molecules by Microglia. In macrophage lineage cells and endothelial cells celastrol decreased induced but not constitutive NO production. Celastrol suppressed adjuvant arthritis in the rat, demonstrating in vivo anti-inflammatory activity. Low doses of celastrol administered to rats significantly improved their performance in memory, learning and psychomotor activity tests. The potent antioxidant and anti-inflammatory activities of celastrol, and its effects on cognitive functions, suggest that the drug may be useful to treat neurodegenerative diseases accompanied by inflammation, such as AD

  129. Anderson I, Adinolfi C, Doctrow S, Huffman K, Joy KA, Malfroy B, Soden P, Rupniak HT, Barnes JC (2001) Oxidative signalling and inflammatory pathways in Alzheimer's disease. Biochem.Soc.Symp.141-149
    Abstract: It is well established that inflammation and oxidative stress are key components of the pathology of Alzheimer's disease (AD), but how early in the pathological cascade these processes are involved or which specific molecular components are key, has not been fully elucidated. This paper describes the pharmacological approach to understand the molecular components of inflammation and oxidative stress on the activation of Microglial cells and neuronal cell viability. We have shown that activation of Microglia with the 42-amino-acid form of the beta-amyloid peptide (A beta 42) activates the production of cyclooxygenase-2, the inducible form of nitric oxide synthase and tumour necrosis factor-alpha and there appears to be little interactive feedback between these three mediators. Moreover, we explore the effects of a series of salen-manganese complexes, EUK-8, -134 and -189, which are known to possess both superoxide and catalase activity. These compounds are able to protect cells from insults produced by hydrogen peroxide or peroxynitrite. Moreover, EUK-134 was also able to limit the output of prostaglandin E2 from activated Microglial cells. The mechanisms underlying these effects are discussed. Together, these data support a pivotal role for oxidative stress and inflammation as key mediators of the pathological cascade in AD and provide some ideas about possible therapeutic targets

  130. Apelt J, Schliebs R (2001) Beta-amyloid-induced glial expression of both pro- and anti-inflammatory cytokines in cerebral cortex of aged transgenic Tg2576 mice with Alzheimer plaque pathology. Brain Res. 894:21-30
    Abstract: To elucidate the mechanisms involved in beta-amyloid-mediated inflammation in Alzheimer's disease, transgenic Tg2576 mice containing as transgene the Swedish double mutation of human amyloid precursor protein 695, were examined for the expression pattern of various cytokines using double immunocytochemistry and laser scanning microscopy. Tg2576 mice studied at postnatal ages of 13, 16 and 19 months demonstrated an age-related accumulation of both senile and diffuse beta-amyloid plaques in neocortex and hippocampus. Reactive interleukin (IL)-1beta-immunoreactive astrocytes were found in close proximity to both fibrillary and diffuse beta-amyloid deposits detectable at very early stages of plaque development, while activated Microglia appeared in and around fibrillary beta-amyloid plaques only. Subpopulations of reactive astrocytes also demonstrated immunolabeling for transforming growth factor (TGF)-beta1, TGF-beta3, and IL-10, already detectable in 13-month-old transgenic mouse brain, while a few IL-6-immunoreactive astrocytes were observed only at later stages of plaque development. The early beta-amyloid-mediated upregulation of IL-1beta, TGF-beta, and IL-10 in surrounding reactive astrocytes indicates the induction of both pro- and anti-inflammatory mechanisms. The transgenic approach used in this study may thus provide a useful tool to further disclose the in vivo mechanisms by which pro- and anti-inflammatory cytokines interact and/or contribute to the progression of Alzheimer's disease

  131. Bacskai BJ, Kajdasz ST, Christie RH, Carter C, Games D, Seubert P, Schenk D, Hyman BT (2001) Imaging of amyloid-beta deposits in brains of living mice permits direct observation of clearance of plaques with immunotherapy. Nat.Med. 7:369-372

  132. Bamberger ME, Landreth GE (2001) Microglial interaction with beta-amyloid: implications for the pathogenesis of Alzheimer's disease. Microsc.Res.Tech. 54:59-70
    Abstract: The etiology of Alzheimer's disease (AD) involves a significant inflammatory component as evidenced by the presence of elevated levels of a diverse range of proinflammatory molecules in the AD brain. These inflammatory molecules are produced principally by activated Microglia, which are found to be clustered within and adjacent to the senile plaque. Moreover, long-term treatment of patients with non-steroidal anti-inflammatory drugs has been shown to reduce risk and incidence of AD and delay disease progression. The Microglia respond to beta-amyloid (Abeta) deposition in the brain through the interaction of fibrillar forms of amyloid with cell surface receptors, leading to the activation of intracellular signal transduction cascades. The activation of multiple independent signaling pathways ultimately leads to the induction of proinflammatory gene expression and production of reactive oxygen and nitrogen species. These Microglial inflammatory products act in concert to produce neuronal toxicity and death. Therapeutic approaches focused on inhibition of the Microglial-mediated local inflammatory response in the AD brain offer new opportunities to intervene in the disease

  133. Bayer TA, Wirths O, Majtenyi K, Hartmann T, Multhaup G, Beyreuther K, Czech C (2001) Key factors in Alzheimer's disease: beta-amyloid precursor protein processing, metabolism and intraneuronal transport. Brain Pathol. 11:1-11
    Abstract: During the last years it has become evident that the beta-amyloid (Abeta) component of senile plaques may be the key molecule in the pathology of Alzheimer's disease (AD). The source and place of the neurotoxic action of Abeta, however, is still a matter of controversy. The precursor of the beta-amyloid peptide is the predominantly neuronal beta-amyloid precursor protein. We, and others, hypothesize that intraneuronal misregulation of APP leads to an accumulation of Abeta peptides in intracellular compartments. This accumulation impairs APP trafficking, which starts a cascade of pathological changes and causes the pyramidal neurons to degenerate. Enhanced Abeta secretion as a function of stressed neurons and remnants of degenerated neurons provide seeds for extracellular Abeta aggregates, which induce secondary degenerative events involving neighboring cells such as neurons, astroglia and macrophages/Microglia. Beta-amyloid precursor protein has a pivotal role in Alzheimer's disease

  134. Benveniste EN, Nguyen VT, O'Keefe GM (2001) Immunological aspects of Microglia: relevance to Alzheimer's disease. Neurochem.Int. 39:381-391
    Abstract: Alzheimer's disease (AD) is a progressive dementing neurologic illness, and the most frequent cause of dementia in the elderly. Neuritic plaques are one of the main neuropathological findings in AD, and the major protein component is the beta-amyloid protein (A beta). Another striking feature of neuritic plaques is the presence of activated Microglia, cytokines, and complement components, suggestive of "inflammatory foci" within AD brain. In this review, we will examine the mechanisms by which Microglia become activated in AD, emphasizing the role in the A beta protein and proinflammatory cytokines. As well, pathways for suppression of Microglial activation by immunosuppressive cytokines will be described. Inflammation mediated by activated Microglia is an important component of AD pathophysiology, and strategies to control this response could provide new therapeutic approaches for the treatment of AD

  135. Blasko I, Apochal A, Boeck G, Hartmann T, Grubeck-Loebenstein B, Ransmayr G (2001) Ibuprofen decreases cytokine-induced amyloid beta production in neuronal cells. Neurobiol.Dis. 8:1094-1101
    Abstract: Trying to decrease the production of Amyloid beta (Abeta) has been envisaged as a promising approach to prevent neurodegeneration in Alzheimer's disease (AD). A chronic inflammatory reaction with activated Microglia cells and astrocytes is a constant feature of AD. The participation of the immune system in the disease process is further documented in several retrospective clinical studies showing an inverse relationship between the prevalence of AD and nonsteroidal anti-inflammatory drug (NSAID) therapy. Previously, we demonstrated that the combination of the proinflammatory cytokines TNFalpha with IFNgamma induces the production of Abeta-42 and Abeta-40 in human neuronal cells. In the present study, the neuronal cell line Sk-n-sh was incubated for 12 h with the cyclooxygenase inhibitor ibuprofen and subsequently stimulated with the cytokines TNFalpha and IFNgamma. Ibuprofen treatment decreased the secretion of total Abeta in the conditioned media of cytokine stimulated cells by 50% and prevented the accumulation of Abeta-42 and Abeta-40 in detergent soluble cell extracts. Viability of neuronal cells measured by detection of apoptosis was neither influenced by ibuprofen nor by cytokine treatment. The reduction in the production of Abeta by ibuprofen was presumably due to a decreased production of betaAPP, which in contrast to the control proteins M2 pyruvate kinase, beta-tubulin and the cytokine inducible ICAM-1 was detected at low concentration in ibuprofen treated cells. The data demonstrate a possible mechanism how ibuprofen may decrease the risk and delay the onset of AD

  136. Cagnin A, Brooks DJ, Kennedy AM, Gunn RN, Myers R, Turkheimer FE, Jones T, Banati RB (2001) In-vivo measurement of activated Microglia in dementia. Lancet 358:461-467
    Abstract: BACKGROUND: Activated Microglia have a key role in the brain's immune response to neuronal degeneration. The transition of Microglia from the normal resting state to the activated state is associated with an increased expression of receptors known as peripheral benzodiazepine binding sites, which are abundant on cells of mononuclear phagocyte lineage. We used brain imaging to study expression of these sites in healthy individuals and patients with Alzheimer's disease. METHODS: We studied 15 normal individuals (age 32-80 years), eight patients with Alzheimer's disease, and one patient with minimal cognitive impairment. Quantitative in-vivo measurements of glial activation were obtained with positron emission tomography (PET) and carbon-11-labelled (R)-PK11195, a specific ligand for the peripheral benzodiazepine binding site. FINDINGS: In normal individuals, regional [11C](R)-PK11195 binding did not significantly change with age, except in the thalamus, where an age-dependent increase was found. By contrast, patients with Alzheimer's disease showed significantly increased regional [11C](R)-PK11195 binding in the entorhinal, temporoparietal, and cingulate cortex. INTERPRETATION: In-vivo detection of increased [11C](R)-PK11195 binding in Alzheimer-type dementia, including mild and early forms, suggests that Microglial activation is an early event in the pathogenesis of the disease

  137. Chung S, Lee J, Joe EH, Uhm DY (2001) Beta-amyloid peptide induces the expression of voltage dependent outward rectifying K+ channels in rat Microglia. Neurosci.Lett. 300:67-70
    Abstract: Upregulation of voltage-dependent outward rectifying K+ (Kv) channels has been reported in activated Microglia. Since beta-amyloid peptide (A beta) is known to activate Microglia, we tested whether the exposure of cultured rat Microglia to A beta fragment 25-35 (A beta 25-35) induced the Kv current. A beta 25-35 in 5-200 nM concentration range significantly increased Kv current density, while there was small change in inward rectifying K+ current density. The full length A beta peptide (A beta 1-42) also increased Kv current. However, the control peptide, A beta 35-25, did not induce Kv current. Most of the Kv current induced by A beta was specifically blocked by the presence of antisense deoxyoligonucleotides against Kv1.3, and Kv1.5. Thus, it is concluded that we have identified Kv1.3 and Kv1.5 as the channel types expressed in A beta-treated Microglia

  138. Clapp-Lilly KL, Smith MA, Perry G, Duffy LK (2001) Melatonin reduces interleukin secretion in amyloid-beta stressed mouse brain slices. Chem.Biol.Interact. 134:101-107
    Abstract: Neurodegeneration in Alzheimer's disease (AD) is associated with many features of the immune system. For example, cytokines such as IL-6, synthesized by Microglia and astrocytes, are associated with senile plaques. To further study the role of cytokines in early stage AD neurodegeneration, an organotypic mouse brain slice culture system with Microglia and astrocytes was developed. Amyloid-beta(Abeta1-40) induced the secretion of both IL-1beta and IL-6. Melatonin, an antioxidant and pineal hormone, reduced interleukin secretion in a concentration dependent manner. We also observed that melatonin, alone, had no effect on IL-1beta secretion but at a concentration of 500 microM induced the secretion of IL-6. This organotypic slice system can be used to study the early role of immune system molecules on neurodegeneration

  139. Combs CK, Karlo JC, Kao SC, Landreth GE (2001) beta-Amyloid stimulation of Microglia and monocytes results in TNFalpha-dependent expression of inducible nitric oxide synthase and neuronal apoptosis. J.Neurosci. 21:1179-1188
    Abstract: Reactive Microglia associated with the beta-amyloid plaques in Alzheimer's disease (AD) brains initiate a sequence of inflammatory events integral to the disease process. We have observed that fibrillar beta-amyloid peptides activate a tyrosine kinase-based signaling response in primary mouse Microglia and the human monocytic cell line, THP-1, resulting in production of neurotoxic secretory products, proinflammatory cytokines, and reactive oxygen species. We report that most of the amyloid-induced tyrosine kinase activity was stimulated after activation of Src family members such as Lyn. However, transduction of the signaling response required for increased production of the cytokines TNFalpha and IL1-beta was mediated by the nonreceptor tyrosine kinase, Syk. Additionally, beta-amyloid stimulated an NFkappaB-dependent pathway in parallel that was required for cytokine production. Importantly, TNFalpha generated by the monocytes and Microglia was responsible for the majority of the neuorotoxic activity secreted by these cells after beta-amyloid stimulation but must act in concert with other factors elaborated by Microglia to elicit neuronal death. Moreover, we observed that the neuronal loss was apoptotic in nature and involved increased neuronal expression of inducible nitric oxide synthase and subsequent peroxynitrite production. Selective inhibitors of inducible nitric oxide synthase effectively protected cells from toxicity associated with the Microglial and monocytic secretory products. This study demonstrates a functional linkage between beta-amyloid-dependent activation of Microglia and several characteristic markers of neuronal death occurring in Alzheimer's disease brains

  140. Dandrea MR, Reiser PA, Gumula NA, Hertzog BM, Andrade-Gordon P (2001) Application of triple immunohistochemistry to characterize amyloid plaque-associated inflammation in brains with Alzheimer's disease. Biotech.Histochem. 76:97-106
    Abstract: Inflammation, characterized by the presence of activated Microglia and reactive astrocytes (gliosis), has been described in Alzheimer's disease (AD). We used our routine single immunohistochemical (IHC) labeling protocol to label amyloid plaques, an AD neuropathological hallmark, activated Microglia, and reactive astrocytes in serial sections of AD hippocampus and entorhinal cortex of brain. Although most amyloid plaques were associated with inflammation throughout the serial sections, the extent of Microglial and astrocytic activation varied among the amyloid plaques. We also observed a population of amyloid plaques that did not appear to coincide with immunolabeled Microglia and astrocytes in serial sections, leading us to speculate that some amyloid plaques are not associated with inflammation. Because serial sectioning limited our ability to confirm these findings, we developed a triple IHC protocol to investigate the association of activated Microglia and reactive astrocytes simultaneously with amyloid plaques in sections of AD brain entorhinal cortex and hippocampus. Unlike the potential errors of extrapolating descriptive information from routine IHC or histochemical staining methods on sectioned tissues, triple IHC allowed direct characterization of three differently colored antigens in situ. The success of the protocol depended on selection of distinguishable color schemes and resolution of other critical technical elements including the compatibility of the reagents and the sensitivity and sequence of the detection systems. The results of the triple IHC protocol clarified the spatial relation of Microglia and astrocytes with amyloid plaques and provoked novel interpretations about the roles of inflammation in AD brain tissues. We categorized three distinct populations of amyloid plaques related to of inflammation: 1) Abeta42 immunoreactive (a marker of amyloid plaques) amyloid plaques without activated Microglia or reactive astrocytes, 2) Abeta42-positive amyloid plaques with HLA-DR (a marker of Microglia)-positive Microglia and no astrocytes, 3) Abeta42-positive amyloid plaques among HLA-DR and GFAP (a marker of astrocytes) immunoreactive astrocytes. Most amyloid plaques had varying degrees of activated Microglia and reactive astrocytes. Some of the amyloid plaques were not associated with inflammation while others were associated only with activated Microglia. These findings suggest that amyloid plaques without associated inflammation may represent recently formed plaques and that the presence of amyloid plaques in AD brains may activate Microglia prior to gliosis. Furthermore, the shape of the amyloid plaques may be altered subsequently from its typical spherical to an aspherical shape by the inflammatory cells

  141. De Groot CJ, Hulshof S, Hoozemans JJ, Veerhuis R (2001) Establishment of Microglial cell cultures derived from postmortem human adult brain tissue: immunophenotypical and functional characterization. Microsc.Res.Tech. 54:34-39
    Abstract: Cell cultures have become an integral part of the daily routine in most biological research laboratories. Because they are very dynamic and highly accessible, cell cultures permit direct experimental manipulations where cause-effect relations can be more definitely assayed. We have developed cultures of Microglial cells from rapid autopsies (range 3-10 hours) of nondemented elderly patients and Alzheimer's disease patients. Cultures were derived from the subcortical white matter, corpus callosum, and frontal, temporal, and occipital cortex. The adherent Microglial cells were immunoreactive for CD68, CD45, CD11c, and major histocompatibility complex (MHC) class II markers, and were not immunoreactive for astrocyte or oligodendrocyte markers. In addition, some functional characteristics of the isolated Microglial cells were also studied. Upon stimulation with lipopolysaccharide (LPS), Microglial cells secreted pro- and antiinflammatory mediators, i.e., interleukin- (IL)-6, prostaglandin E2 (PGE2), and IL-10, indicating the functional capacity of cultured Microglia

  142. Ferencik M, Novak M, Rovensky J, Rybar I (2001) Alzheimer's disease, inflammation and non-steroidal anti-inflammatory drugs. Bratisl.Lek.Listy 102:123-132
    Abstract: Alzheimer's disease (AD) is a degenerative disease of the brain, which causes dementia. The disease is characterised by three main pathogenic factors: senile plaques, neurofibrillary tangles and inflammation. the participation of the local inflammatory reaction is confirmed especially by the results of studies dealing with activated Microglia, reactive astrocytes, complement system, cytokines, reactive mediators of oxygen and nitrogen (free radicals), all of which participate significantly in inflammatory processes. These inflammatory markers are locally produced by brain cells, and occur in close proximity of beta-amyloid and tau protein deposits. Moreover, some epidemiologic and pilot clinical studies have proven that long-term administration of anti-inflammatory drugs have a protective effect on the onset of AD. Out of them, non-steroidal anti-inflammatory drugs (NSAIDs) are most extensively investigated medicaments. Despite some contradictory findings, the prevalent majority of these studies prove that long-term application of anti-inflammatory treatment can delay the onset, or at least slow down the progression of AD, namely in people between 65 and 75 years of age. The most appropriate prophylactic effect seems to be achieved by specific inhibitors of cyclooxygenase-2 (COX-2), namely celecoxib and rofecoxib. These preparations protect the gastrointestinal tract better than classical NSAIDs which inhibit both isoenzymes--COX-1 and COX-2. COX-2 is expressed in higher concentrations in the degenerating cells of the brain and this excessive expression can be decreased by selective inhibitors. The latter decrease also the excessive activation of some transcription factors (PPARgama and the nuclear factor kapa-B), which are responsible for the initiation of transcription of a number of pro-inflammatory genes. The selective inhibitors COX-2 can thereby have an anti-inflammatory effect operating on several levels. (Tab. 1, Fig. 1, Ref. 75.)

  143. Gebicke-Haerter PJ, Spleiss O, Ren LQ, Li H, Dichmann S, Norgauer J, Boddeke HW (2001) Microglial chemokines and chemokine receptors. Prog.Brain Res. 132:525-532

  144. Glabe C (2001) Intracellular mechanisms of amyloid accumulation and pathogenesis in Alzheimer's disease. J.Mol.Neurosci. 17:137-145
    Abstract: Cell-culture studies have revealed some of the fundamental features of the interaction of amyloid Abeta with cells and the mechanism of amyloid accumulation and pathogenesis in vitro. A(beta)1-42, the longer isoform of amyloid that is preferentially concentrated in senile plaque (SP) amyloid deposits in Alzheimer's disease (AD), is resistant to degradation and accumulates as insoluble aggregates in late endosomes or lysosomes. Once these aggregates have nucleated inside the cell, they grow by the addition of aberrantly folded APP and amyloidgenic fragments of APP, that would otherwise be degraded, onto the amyloid lattice in a fashion analogous to prion replication. This accumulation of heterogeneous aggregated APP fragments and Abeta appears to mimic the pathophysiologyof dystrophic neurites, where the same spectrum of components has been identified by immunohistochemistry. In the brain, this residue appears to be released into the extracellular space, possibly by a partially apoptotic mechanism that is restricted to the distal compartments of the neuron. Ultimately, this insoluble residue may be further digested to the protease-resistant A(beta)n-42 core, perhaps by Microglia, where it accumulates as senile plaques. Thus, the dystrophic neurites are likely to be the source of the immediate precursors of amyloid in the senile plaques. This is the opposite of the commonly held view that extracellular accumulation of amyloid induces dystrophic neurites. Many of the key pathological events of AD may also be directly related to the intracellular accumulation of this insoluble amyloid. The aggregated, intracellular amyloid induces the production of reactive oxygen species (ROS) and lipid peroxidation products and ultimately results in the leakage of the lysosomal membrane. The breakdown of the lysosomal membrane may be a key pathogenic event, leading to the release of heparan sulfate and lysosomal hydrolases into the cytosol. Together, these observations provide the novel view that amyloid deposits and some of the early events of amyloid pathogenesis initiate randomly within single cells in AD. This pathogenic mechanism can explain some of the more enigmatic features of Alzheimer's pathogenesis, like the focal nature of amyloid plaques, the relationship between amyloid, dystrophic neurites and neurofibrillary-tangle pathology, and the miscompartmentalization of extracellular and cytosolic components observed in AD brain

  145. Gyure KA, Durham R, Stewart WF, Smialek JE, Troncoso JC (2001) Intraneuronal abeta-amyloid precedes development of amyloid plaques in Down syndrome. Arch.Pathol.Lab Med. 125:489-492
    Abstract: CONTEXT: Down syndrome patients who live to middle age invariably develop the neuropathologic features of Alzheimer disease, providing a unique situation in which to study the early and sequential development of these changes. OBJECTIVE: To study the development of amyloid deposits, senile plaques, astrocytic and Microglial reactions, and neurofibrillary tangles in the brains of young individuals (<30 years of age) with Down syndrome. METHODS: Histologic and immunocytochemical study of a series of autopsy brains (n = 14, from subjects aged 11 months to 56 years, with 9 subjects <30 years) examined at the Office of the Chief Medical Examiner of the State of Maryland and The Johns Hopkins Hospital. RESULTS: The principal observations included the presence of intraneuronal Abeta immunostaining in the hippocampus and cerebral cortex of very young Down syndrome patients (preceding the extracellular deposition of Abeta) and the formation of senile plaques and neurofibrillary tangles. CONCLUSIONS: We propose the following sequence of events in the development of neuropathologic changes of Alzheimer disease in Down syndrome: (1) intracellular accumulation of Abeta in neurons and astrocytes, (2) deposition of extracellular Abeta and formation of diffuse plaques, and (3) development of neuritic plaques and neurofibrillary tangles with activation of Microglial cells

  146. Hasegawa H, Nakai M, Tanimukai S, Taniguchi T, Terashima A, Kawamata T, Fukunaga K, Miyamoto E, Misaki K, Mukai H, Tanaka C (2001) Microglial signaling by amyloid beta protein through mitogen-activated protein kinase mediating phosphorylation of MARCKS. Neuroreport 12:2567-2571
    Abstract: Myristoylated alanine-rich C kinase substrate (MARCKS), an acidic protein associated with cell motility and phagocytosis, is activated upon phosphorylation by protein kinase C (PKC) and proline-directed protein kinases. In Alzheimer disease (AD), activated Microglia expressing MARCKS migrates around senile plaques. We reported that amyloid beta protein (A beta), a major component of senile plaques, activated MARCKS through a tyrosine kinase and PKC-delta. We have now identified another A beta signaling pathway through a mitogen-activated protein kinase (MAPK) involved in the phosphorylation of MARCKS and analysed cross-talk between PKC and MAPK pathways in primary cultured rat Microglia. A selective inhibitor for MAPK kinase, PD098059, significantly inhibited the phosphorylation of MARCKS induced by A beta. Extracellulary regulated kinases, the activities of which were induced by A beta, directly phosphorylated a recombinant MARCKS in vitro. The MAPK pathway was sensitive to wortmannin, but not to a PKC inhibitor or to tyrosine kinase inhibitors. The activation of PKC by A beta was not sensitive to wortmannin. Our findings suggest involvement of the MAPK pathway through phosphoinositol 3-kinase in the phosphorylation of MARCKS in rat cultured Microglia, an event may be associated with mechanisms activating Microglia in AD

  147. Hass S, Weidemann A, Utermann G, Baier G (2001) Intracellular apolipoprotein E affects Amyloid Precursor Protein processing and amyloid Abeta production in COS-1 cells. Mol.Genet.Genomics 265:791-800
    Abstract: The apoE gene has been identified as a major susceptibility locus for late-onset Alzheimer's disease (LOAD). The epsilon4 allele greatly reduces age of onset of LOAD as compared to the wild-type 3 allele. The molecular mechanism(s) underlying the association has not yet been fully elucidated. The apoE protein has been shown to physically interact with the Abeta region of the Amyloid Precursor Protein (APP), but also with the ectodomain of the APP holoprotein itself. In this study we have used apoE fusion proteins containing either the ER retention sequence KDEL or trans-Golgi network (TGN) signal sequence in order to define potential apoE-mediated alterations in APP protein processing. Co-expression and pulse-chase experiments showed that a functional apoE:APP interaction occurs intracellularly which directly affects maturation and subsequently the secretion kinetics of APP. In addition, an epsilon4 allele-specific induction of Abeta production has been demonstrated. apoE3 resulted in increased Abeta production only when targeted to the ER, as observed in cells transfected with an apoE3KDEL fusion protein as well as following treatment with brefeldin A. The findings suggest that in cells that express both apoE and APP, such as astrocytes and Microglia, a functional apoE:APP interaction may occur which modulates APP processing and Abeta production

  148. Head E, Azizeh BY, Lott IT, Tenner AJ, Cotman CW, Cribbs DH (2001) Complement association with neurons and beta-amyloid deposition in the brains of aged individuals with Down Syndrome. Neurobiol.Dis. 8:252-265
    Abstract: To study the link between beta-amyloid (Abeta) and neuroinflammation, we examined the levels of complement as a function of age and extent of Abeta deposition in Down Syndrome (DS) brain. C1q, the first component of the complement cascade, was visualized using immunohistochemistry in the frontal, entorhinal cortex, and hippocampus of 12 DS ranging from 31 to 69 years of age. C1q was consistently associated with thioflavine-S positive Abeta plaques in DS brain and increased with more extensive age-dependent Abeta deposition. In contrast, little or no C1q labeling was associated with diffuse or thioflavine-S negative Abeta deposits. Neurons in the hippocampus and entorhinal cortex, but less frequently in frontal cortex, were C1q positive in DS cases with sufficient neuropathology to have a diagnosis of Alzheimer's disease. C1q-positive neurons were associated with activated Microglia. These results provide evidence for Abeta-mediated inflammatory factors contributing to the rapid accumulation of neuropathology in DS brain

  149. Head E, Garzon-Rodriguez W, Johnson JK, Lott IT, Cotman CW, Glabe C (2001) Oxidation of Abeta and plaque biogenesis in Alzheimer's disease and Down syndrome. Neurobiol.Dis. 8:792-806
    Abstract: The processes involved with beta-amyloid (Abeta) degradation and clearance in human brain are not well understood. We hypothesized that the distribution of oxidatively modified Abeta, as determined by an affinity-purified antibody in the entorhinal and frontal cortices of Alzheimer's disease (AD), Down syndrome (DS), nondemented elderly control cases, and canine brain, would provide insight into the mechanisms of Abeta accumulation. Based upon plaque counts, oxidized Abeta was present within 46-48% of diffuse and primitive plaques and 98% of cored plaques. Dense punctate deposits of oxidized Abeta were distributed throughout the neuropil in AD and DS brains but were also present within controls with mild neuropathology and isolated cognitive impairments. Confocal studies indicate that punctate oxidized Abeta deposits were within activated Microglia. Oxidatively modified Abeta may reflect the efforts of Microglial cells to take up and degrade Abeta. Oxidative modification of Abeta may be an early event in Abeta pathogenesis and may be important for plaque biogenesis

  150. Heneka MT, Wiesinger H, Dumitrescu-Ozimek L, Riederer P, Feinstein DL, Klockgether T (2001) Neuronal and glial coexpression of argininosuccinate synthetase and inducible nitric oxide synthase in Alzheimer disease. J.Neuropathol.Exp.Neurol. 60:906-916
    Abstract: The enzyme argininosuccinate synthetase (ASS) is the rate limiting enzyme in the metabolic pathway leading from L-citrulline to L-arginine, the physiological substrate of all isoforms of nitric oxide synthases (NOS). ASS and inducible NOS (iNOS) expression in neurons and glia was investigated by immunohistochemistry in brains of Alzheimer disease (AD) patients and nondemented, age-matched controls. In 3 areas examined (hippocampus, frontal, and entorhinal cortex), a marked increase in neuronal ASS and iNOS expression was observed in AD brains. GFAP-positive astrocytes expressing ASS were not increased in AD brains versus controls, whereas the number of iNOS expressing GFAP-positive astrocytes was significantly higher in AD brains. Density measurements revealed that ASS expression levels were significantly higher in glial cells of AD brains. Colocalization of ASS and iNOS immunoreactivity was detectable in neurons and glia. Occasionally, both ASS-and iNOS expression was detectable in CD 68-positive activated Microglia cells in close proximity to senile plaques. These results suggest that neurons and astrocytes express ASS in human brain constitutively, whereas neuronal and glial ASS expression increases parallel to iNOS expression in AD. Because an adequate supply of L-arginine is indispensable for prolonged NO generation, coinduction of ASS enables cells to sustain NO generation during AD by replenishing necessary supply of L-arginine

  151. Hoozemans JJ, Rozemuller AJ, Janssen I, De Groot CJ, Veerhuis R, Eikelenboom P (2001) Cyclooxygenase expression in Microglia and neurons in Alzheimer's disease and control brain. Acta Neuropathol.(Berl) 101:2-8
    Abstract: Epidemiological studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs) lower the risk of developing Alzheimer's disease (AD). Most NSAIDs act upon local inflammatory events by inhibiting the expression or activation of cylooxygenase (COX). In the present study the expression of COX-1 and COX-2 in AD and non-demented control temporal and frontal cortex was investigated using immunohistochemistry. COX-1 expression was detected in Microglial cells, while COX-2 expression was found in neuronal cells. In AD brains, COX-1-positive Microglial cells were primarily associated with amyloid beta plaques, while the number of COX-2-positive neurons was increased compared to that in control brains. No COX expression was detected in astrocytes. In vitro, primary human Microglial and astrocyte cultures, and human neuroblastoma cells (SK-N-SH) were found to secrete prostaglandin E2 (PGE2), especially when stimulated. PGE2 synthesis by astrocytes and SK-N-SH cells was stimulated by interleukin-1beta. Microglial cell PGE2 synthesis was stimulated by lipopolysaccharide only. Although astrocytes are used in studies in vitro to investigate the role of COX in AD, there are no indications that these cells express COX-1 or COX-2 in vivo. The different distribution patterns of COX-1 and COX-2 in AD could implicate that these enzymes are involved in different cellular processes in the pathogenesis of AD

  152. Hoozemans JJ, Rozemuller AJ, Veerhuis R, Eikelenboom P (2001) Immunological aspects of Alzheimer's disease: therapeutic implications. BioDrugs. 15:325-337
    Abstract: Alzheimer's disease (AD) is a chronic neurodegenerative disease causing progressive impairment of memory and cognitive function. The amyloid cascade hypothesis suggests that mismetabolism of the beta-amyloid (A beta) precursor protein (APP) followed by subsequent formation of non-fibrillar and fibrillar A beta deposits leads to glial activation and eventually to neurotoxicity, causing cognitive impairment. Several lines of evidence indicate that an inflammatory process contributes to the pathology of AD. First, inflammatory proteins have been identified as being associated with neuritic plaques and in glial cells surrounding these plaques. Second, certain polymorphisms of acute-phase proteins and cytokines associated with AD plaques increase the risk or predispose for earlier onset of developing AD. Third, epidemiological studies indicate that anti-inflammatory drugs can retard the development of AD. Several steps in the pathological cascade of AD have been identified as possible targets for actions of nonsteroidal anti-inflammatory drugs. For instance, Microglia are considered a target because this cell type is closely involved in AD pathology through secretion of neurotoxic substances and by modulating a positive feedback loop of the inflammatory mechanism that may be involved in the pathological cascade in AD. On the basis of studies in APP transgenic mice, immunisation with A beta was recently suggested as a novel immunological approach for the treatment of AD. Immunisation elicits A beta-specific antibodies that could affect several early steps of the amyloid-driven cascade. Antibodies could prevent A beta from aggregating into fibrils and accelerate clearance of A beta by stimulating its removal by Microglial cells. This review outlines the pathological and genetic evidence that an inflammatory mechanism is involved in AD and the therapeutic approaches based on inhibition or mediation of inflammation

  153. Husemann J, Silverstein SC (2001) Expression of scavenger receptor class B, type I, by astrocytes and vascular smooth muscle cells in normal adult mouse and human brain and in Alzheimer's disease brain. Am.J.Pathol. 158:825-832
    Abstract: In Alzheimer's disease (AD), fibrillar beta-amyloid protein (fAbeta) accumulates in the walls of cerebral vessels associated with vascular smooth muscle cells (SMCs), endothelium, and pericytes, and with Microglia and astrocytes in plaques in the brain parenchyma. Scavenger receptor class A (SR-A) and class B, type I (SR-BI) mediate binding and ingestion of fAbeta by cultured human fetal Microglia, Microglia from newborn mice, and by cultured SMCs. Our findings that SR-BI participates in the adhesion of cultured Microglia from newborn SR-A knock-out mice to fAbeta-coated surfaces, and that Microglia secrete reactive oxygen species when they adhere to these surfaces prompted us to explore expression of SR-BI in vivo. We report here that astrocytes and SMCs in normal adult mouse and human brains and in AD brains express SR-BI. In contrast, Microglia in normal adult mouse and human brains and in AD brains do not express SR-BI. These findings indicate that SR-BI may mediate interactions between astrocytes or SMCs and fAbeta, but not of Microglia and fAbeta, in AD, and that expression of SR-BI by rodent Microglia is developmentally regulated. They suggest that SR-BI expression also is developmentally regulated in human Microglia

  154. Husemann J, Loike JD, Kodama T, Silverstein SC (2001) Scavenger receptor class B type I (SR-BI) mediates adhesion of neonatal murine Microglia to fibrillar beta-amyloid. J.Neuroimmunol. 114:142-150
    Abstract: Class A scavenger receptors (SR-A) mediate Microglial interaction with fibrillar beta-amyloid (fAbeta). We report here that neonatal Microglia from SR-A knockout mice (SR-A-/-) adhere to surface-bound fAbeta, and produce reactive oxygen species (ROS) as efficiently as wildtype Microglia; that both wildtype and SR-A-/- Microglia express SR-BI; that antibodies against SR-BI do not affect adhesion or ROS production by wildtype Microglia, but inhibit adhesion and ROS production of SR-A-/- Microglia to immobilized fAbeta by approximately 40%. Adhesion to fAbeta-coated surfaces, and uptake of fAbeta by both wildtype and SR-A-/- Microglia was almost completely inhibited by incubation with fucoidan. Thus SR-BI and SR-A mediate similar effector functions in neonatal Microglia, which suggests that SR-BI plays as important a role as SR-A, and can maintain the wildtype phenotype in SR-A-/- Microglia

  155. Imamura K, Sawada M, Ozaki N, Naito H, Iwata N, Ishihara R, Takeuchi T, Shibayama H (2001) Activation mechanism of brain Microglia in patients with diffuse neurofibrillary tangles with calcification: a comparison with Alzheimer disease. Alzheimer Dis.Assoc.Disord. 15:45-50
    Abstract: Diffuse neurofibrillary tangles with calcification (DNTC) is an atypical dementia and is characterized pathologically by diffuse neurofibrillary tangles (NFTs) without senile plaques (SPs). In this study, we investigated the distribution of human leukocyte antigen (HLA)-DR-positive activated Microglia in postmortem brain tissue of six patients with DNTC and six patients with Alzheimer disease (AD). HLA-DR-positive activated Microglia were observed to associate with SPs in AD. In the DNTC brain, which lacks SPs, HLA-DR-positive Microglia were mainly accumulated around weakly tau-positive NFTs, which were also positive for anti-amyloid-P and anti-C3d antibodies. The results of this study suggest that the complement pathway is also activated in the DNTC brain and that immune and inflammatory responses, including Microglia activation, may occur around extracellular NFTs in DNTC patients

  156. Jellinger KA, Stadelmann C (2001) Problems of cell death in neurodegeneration and Alzheimer's Disease. J.Alzheimers.Dis. 3:31-40
    Abstract: Progressive cell loss in specific neuronal populations is a pathological hallmark of neurodegenerative diseases, but its mechanisms remain unresolved. Apoptosis or alternative pathways of neuronal death have been discussed in Alzheimer disease (AD) and other disorders. However, DNA fragmentation in human brain as a sign of neuronal injury is too frequent to account for the continuous loss in these slowly progressive diseases. In autopsy cases of AD, Parkinson's disease (PD), related disorders, and age-matched controls, DNA fragmentation using the TUNEL method and an array of apoptosis-related proteins (ARP), proto-oncogenes, and activated caspase 3, the key enzyme of late-stage apoptosis, were examined. In AD, a considerable number of hippocampal neurons and glial cells showed DNA fragmentation with a 3- to 6-fold increase related to amyloid deposits and neurofibrillary tangles, but only one in 2.600 to 5.650 neurons displayed apoptotic morphology and cytoplasmic immunoreactivity for activated caspase~3, whereas no neurons were labeled in age-matched controls. Caspase~3 immunoreactivity was seen in granules of cells with granulovacuolar degeneration, in around 25% In progressive supranuclear palsy, only single neurons but oligodendrocytes in brainstem, around 25% TUNEL-positive and expressed both ARPs and activated caspase 3. In PD, dementia with Lewy bodies, and multisystem atrophy (MSA), TUNEL-positivity and expression of ARPs or activated caspase~3 were only seen in Microglia and oligodendrocytes with cytoplasmic inclusions in MSA, but not in neurons. These data provide evidence for extremely rare apoptotic neuronal death in AD and PSP compatible with the progression of neuronal degeneration in these chronic diseases. Apoptosis mainly involves reactive Microglia and oligodendroglia, the latter occasionally involved by deposits of insoluble fibrillary proteins, while alternative mechanisms of neuronal death may occur. Susceptible cell populations in a proapoptotic environment, particularly in AD, show increased vulnerability towards metabolic or other noxious factors, with autophagy as a possible protective mechanism in early stages of programmed cell death. The intracellular cascade leading to cell death still awaits elucidation

  157. Johnson S (2001) Gradual micronutrient accumulation and depletion in Alzheimer's disease. Med.Hypotheses 56:595-597
    Abstract: Cadmium is a carcinogen that accumulates relentlessly with age, reaching high levels in the liver and kidneys. It is known to hyperactivate the Kupffer cells (hepatic macrophages). On the other hand, the risk of developing Alzheimer's disease increases considerably with age and it involves neuronal damage by hyperactive Microglia (brain macrophages). Moreover, many of the metals that accumulate in the liver and kidneys, also accumulate in the brain (Fe, Cu, Zn, Mn, etc.). Therefore, it is possible that Cd also hyperactivates the Microglia, playing a role in Alzheimer's disease (AD).Fe also accumulates in the brain as we age and catalyzes super oxide (O2-) formation, which reacts with nitric oxide (NO) to form the very harmful peroxynitrite (ONOO-)

  158. Jones RW (2001) Inflammation and Alzheimer's disease. Lancet 358:436-437

  159. Kang J, Park EJ, Jou I, Kim JH, Joe EH (2001) Reactive oxygen species mediate A beta(25-35)-induced activation of BV-2 Microglia. Neuroreport 12:1449-1452
    Abstract: Microglial activation induced by beta-amyloid (A beta) is an important cellular response in the pathogenesis of Alzheimer's disease (AD). In this study, we show that reactive oxygen species (ROS) play a role as signaling molecules for the activation of NF-kappaB and induction of IL-1beta mRNA expression in A beta(25-35)-treated murine Microglia BV-2 cells. ROS scavengers such catalase and superoxide dismutase (SOD) mimetics obviously reduced activation of NF-kappaB and the elevated level of IL-1beta transcripts induced by A beta(25-35). In addition, the A beta(25-35)-induced NF-kappaB activation and IL-1beta expression were suppressed by blockers of the ROS generating enzymes such as NADPH oxidase, cyclooxygenase, and lipoxygenase. These data suggest that ROS mediate A beta-induced Microglial activation

  160. Krause KH, Clark RA (2001) Geneva Biology of Ageing Workshop 2000: phagocytes, inflammation, and ageing. Exp.Gerontol. 36:373-381

  161. Landreth GE, Heneka MT (2001) Anti-inflammatory actions of peroxisome proliferator-activated receptor gamma agonists in Alzheimer's disease. Neurobiol.Aging 22:937-944
    Abstract: The role of inflammatory processes in the brains of Alzheimer's Disease (AD) patients has recently attracted considerable interest. Indeed, the only demonstrated effective therapy for AD patients is long-term treatment with non-steroidal anti-inflammatory drugs (NSAIDs). The mechanistic basis of the efficacy of NSAIDs in AD remains unclear. However, the recent recognition that NSAIDs can bind to and activate the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma), has offered an explanation for the action of these drugs in AD. PPARgamma activation leads to the inhibition of Microglial activation and the expression of a broad range of proinflammatory molecules. The newly appreciated anti-inflammatory actions of PPARgamma agonists may allow novel therapies for AD and other CNS indications with an inflammatory component

  162. Le TV, Crook R, Hardy J, Dickson DW (2001) Cotton wool plaques in non-familial late-onset Alzheimer disease. J.Neuropathol.Exp.Neurol. 60:1051-1061
    Abstract: Cotton wool plaques (CWP) are large, ball-like plaques lacking dense amyloid cores that displace adjacent structures. They were first described in a Finnish kindred with early-onset Alzheimer disease (AD) with spastic paraparesis due to a presenilin-1 delta9 mutation. We describe a case of sporadic late-onset AD with numerous neocortical CWP as well as severe amyloid angiopathy and marked leukoencephalopathy, compared with 16 cases of late-onset AD with similar degrees of amyloid angiopathy and leukoencephalopathy. The cases were studied with histologic methods and with single and double immunostaining for beta-amyloid (Abeta), paired helical filaments-tau (PHF-tau), neurofilament (NF), glial fibrillary acidic protein (GFAP), HLA-DR, and amyloid precursor protein (APP). We found that CWP were well-circumscribed amyloid deposits infiltrated by ramified Microglia and surrounded by dystrophic neurites that were immunopositive for APP, but only weakly for NF and PHF-tau. Abeta1-12 was diffuse throughout the CWP, while Abeta37-42 was peripherally located and Abeta20-40 more centrally located. Two of the 16 late-onset AD cases also had CWP, but they were also admixed with diffuse plaques and plaques with dense amyloid cores. Pyramidal tract degeneration was not a consistent finding or a prominent feature in any case. The results suggest that CWP are not specific for early-onset familial AD with spastic paraparesis

  163. Le Y, Gong W, Tiffany HL, Tumanov A, Nedospasov S, Shen W, Dunlop NM, Gao JL, Murphy PM, Oppenheim JJ, Wang JM (2001) Amyloid (beta)42 activates a G-protein-coupled chemoattractant receptor, FPR-like-1. J.Neurosci. 21:RC123
    Abstract: Amyloid beta (Abeta) is a major contributor to the pathogenesis of Alzheimer's disease (AD). Although Abeta has been reported to be directly neurotoxic, it also causes indirect neuronal damage by activating mononuclear phagocytes (Microglia) that accumulate in and around senile plaques. In this study, we show that the 42 amino acid form of beta amyloid peptide, Abeta(42), is a chemotactic agonist for a seven-transmembrane, G-protein-coupled receptor named FPR-Like-1 (FPRL1), which is expressed on human mononuclear phagocytes. Moreover, FPRL1 is expressed at high levels by inflammatory cells infiltrating senile plaques in brain tissues from AD patients. Thus, FPRL1 may mediate inflammation seen in AD and is a potential target for developing therapeutic agents

  164. Lim GP, Chu T, Yang F, Beech W, Frautschy SA, Cole GM (2001) The curry spice curcumin reduces oxidative damage and amyloid pathology in an Alzheimer transgenic mouse. J.Neurosci. 21:8370-8377
    Abstract: Inflammation in Alzheimer's disease (AD) patients is characterized by increased cytokines and activated Microglia. Epidemiological studies suggest reduced AD risk associates with long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs). Whereas chronic ibuprofen suppressed inflammation and plaque-related pathology in an Alzheimer transgenic APPSw mouse model (Tg2576), excessive use of NSAIDs targeting cyclooxygenase I can cause gastrointestinal, liver, and renal toxicity. One alternative NSAID is curcumin, derived from the curry spice turmeric. Curcumin has an extensive history as a food additive and herbal medicine in India and is also a potent polyphenolic antioxidant. To evaluate whether it could affect Alzheimer-like pathology in the APPSw mice, we tested a low (160 ppm) and a high dose of dietary curcumin (5000 ppm) on inflammation, oxidative damage, and plaque pathology. Low and high doses of curcumin significantly lowered oxidized proteins and interleukin-1beta, a proinflammatory cytokine elevated in the brains of these mice. With low-dose but not high-dose curcumin treatment, the astrocytic marker GFAP was reduced, and insoluble beta-amyloid (Abeta), soluble Abeta, and plaque burden were significantly decreased by 43-50%. However, levels of amyloid precursor (APP) in the membrane fraction were not reduced. Microgliosis was also suppressed in neuronal layers but not adjacent to plaques. In view of its efficacy and apparent low toxicity, this Indian spice component shows promise for the prevention of Alzheimer's disease

  165. Lue LF, Walker DG, Rogers J (2001) Modeling Microglial activation in Alzheimer's disease with human postmortem Microglial cultures. Neurobiol.Aging 22:945-956
    Abstract: Alzheimer's disease (AD) is a uniquely human disorder. Despite intense research, the lack of availability of model systems has hindered AD studies though in recent years transgenic mouse models have been produced, which develop AD-like amyloid beta peptide (Abeta) plaques. For the study of inflammatory changes in AD brains, these transgenic mice may have limitations due to differences in the innate immune system of humans and rodents. Many studies of inflammatory processes in AD have focused on the role of activated Microglia. Over the last 8 years, our research has focused on the properties of human Microglia cultured from brain tissues of AD and non-demented (ND) individuals. As these are the cells observed to be activated in AD tissues, they represent a useful system for modeling the inflammatory components of AD.In this review, we summarize data by our group and others on the use of Microglia for AD-related inflammatory research, with emphasis on results using human postmortem brain Microglia. A range of products have been shown to be produced by human postmortem Microglia, both constitutively and in response to treatment with Abeta, including proinflammatory cytokines such as interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF) alpha, and macrophage colony stimulating factor (M-CSF), along with complement proteins, especially C1q, superoxide radicals and neurotoxic factors. In our studies, we have demonstrated that there was a significant difference between AD and ND Microglia in terms of their secretion of M-CSF and C1q. We also discuss the role of putative Abeta Microglial receptors, particular recent data showing a role for the receptor for advanced glycation endproducts (RAGE) in mediating the responses of human Microglia to Abeta. Finally, our studies on the use of an Abeta spot paradigm to model Microglia interactions with plaques demonstrated that many of the features of AD inflammation can be modeled with postmortem brain derived Microglia

  166. Lue LF, Rydel R, Brigham EF, Yang LB, Hampel H, Murphy GM, Jr., Brachova L, Yan SD, Walker DG, Shen Y, Rogers J (2001) Inflammatory repertoire of Alzheimer's disease and nondemented elderly Microglia in vitro. Glia 35:72-79
    Abstract: We have previously developed and characterized isolated Microglia and astrocyte cultures from rapid (<4 h) brain autopsies of Alzheimer's disease (AD) and nondemented elderly control (ND) patients. In the present study, we evaluate the inflammatory repertoire of AD and ND Microglia cultured from white matter (corpus callosum) and gray matter (superior frontal gyrus) with respect to three major proinflammatory cytokines, three chemokines, a classical pathway complement component, a scavenger cell growth factor, and a reactive nitrogen intermediate. Significant, dose-dependent increases in the production of pro-interleukin-1beta (pro-IL-1beta), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory peptide-1alpha (MIP-1alpha), IL-8, and macrophage colony-stimulating factor (M-CSF) were observed after exposure to pre-aggregated amyloid beta peptide (1-42) (Abeta1-42). Across constitutive and Abeta-stimulated conditions, secretion of complement component C1q, a reactive nitrogen intermediate, and M-CSF was significantly higher in AD compared with ND Microglia. Taken together with previous in situ hybridization findings, these results demonstrate unequivocally that elderly human Microglia provide a brain endogenous source for a wide range of inflammatory mediators

  167. Lue LF, Walker DG, Brachova L, Beach TG, Rogers J, Schmidt AM, Stern DM, Yan SD (2001) Involvement of Microglial receptor for advanced glycation endproducts (RAGE) in Alzheimer's disease: identification of a cellular activation mechanism. Exp.Neurol. 171:29-45
    Abstract: Receptor-mediated interactions with amyloid beta-peptide (Abeta) could be important in the evolution of the inflammatory processes and cellular dysfunction that are prominent in Alzheimer's disease (AD) pathology. One candidate receptor is the receptor for advanced glycation endproducts (RAGE), which can bind Abeta and transduce signals leading to cellular activation. Data are presented showing a potential mechanism for Abeta activation of Microglia that could be mediated by RAGE and macrophage colony-stimulating factor (M-CSF). Using brain tissue from AD and nondemented (ND) individuals, RAGE expression was shown to be present on Microglia and neurons of the hippocampus, entorhinal cortex, and superior frontal gyrus. The presence of increased numbers of RAGE-immunoreactive Microglia in AD led us to further analyze RAGE-related properties of these cells cultured from AD and ND brains. Direct addition of Abeta(1-42) to the Microglia increased their expression of M-CSF. This effect was significantly greater in Microglia derived from AD brains compared to those from ND brains. Increased M-CSF secretion was also demonstrated using a cell culture model of plaques whereby Microglia were cultured in wells containing focal deposits of immobilized Abeta(1-42). In each case, the Abeta stimulation of M-CSF secretion was significantly blocked by treatment of cultures with anti-RAGE F(ab')2. Treatment of Microglia with anti-RAGE F(ab')2 also inhibited the chemotactic response of Microglia toward Abeta(1-42). Finally, incubation of Microglia with M-CSF and Abeta increased expression of RAGE mRNA. These Microglia also expressed M-CSF receptor mRNA. These data suggest a positive feedback loop in which Abeta-RAGE-mediated Microglial activation enhances expression of M-CSF and RAGE, possibly initiating an ascending spiral of cellular activation

  168. Malchiodi-Albedi F, Domenici MR, Paradisi S, Bernardo A, Ajmone-Cat MA, Minghetti L (2001) Astrocytes contribute to neuronal impairment in beta A toxicity increasing apoptosis in rat hippocampal neurons. Glia 34:68-72
    Abstract: Astrocytosis is a common feature of amyloid plaques, the hallmark of Alzheimer's disease (AD), along with activated Microglia, neurofibrillary tangles, and beta-amyloid (beta A) deposition. However, the relationship between astrocytosis and neurodegeneration remains unclear. To assess whether beta A-stimulated astrocytes can damage neurons and contribute to beta A neurotoxicity, we studied the effects of beta A treatment in astrocytic/neuronal co-cultures, obtained from rat embryonic brain tissue. We found that in neuronal cultures conditioned by beta A-treated astrocytes, but not directly in contact with beta A, the number of apoptotic cells increased, doubling the values of controls. In astrocytes, beta A did not cause astrocytic cell death, nor did produce changes in nitric oxide or prostaglandin E(2) levels. In contrast, S-100 beta expression was remarkably increased. Our data show for the first time that beta A--astrocytic interaction produces a detrimental effect on neurons, which may contribute to neurodegeneration in AD

  169. Martins RN, Taddei K, Kendall C, Evin G, Bates KA, Harvey AR (2001) Altered expression of apolipoprotein E, amyloid precursor protein and presenilin-1 is associated with chronic reactive gliosis in rat cortical tissue. Neuroscience 106:557-569
    Abstract: A major characteristic feature of Alzheimer's disease is the formation of compact, extracellular deposits of beta-amyloid (senile plaques). These deposits are surrounded by reactive astrocytes, Microglia and dystrophic neurites. Mutations in three genes have been implicated in early-onset familial Alzheimer's disease. However, inflammatory changes and astrogliosis are also believed to play a role in Alzheimer's pathology. What is unclear is the extent to which these factors initiate or contribute to the disease progression. Previous rat studies demonstrated that heterotopic transplantation of foetal cortical tissue onto the midbrain of neonatal hosts resulted in sustained glial reactivity for many months. Similar changes were not seen in cortex-to-cortex grafts. Using this model of chronic cortical gliosis, we have now measured reactive changes in the levels of the key Alzheimer's disease proteins, namely the amyloid precursor protein, apolipoprotein E and presenilin-1. These changes were visualised immunohistochemically and were quantified by western blot analysis. We report here that chronic cortical gliosis in the rat results in a sustained increase in the levels of apolipoprotein E and total amyloid precursor protein. Reactive astrocytes in heterotopic cortical grafts were immunopositive for both of these proteins. Using a panel of amyloid precursor protein antibodies we demonstrate that chronic reactive gliosis is associated with alternative cleavage of the peptide. No significant changes in apolipoprotein E or amyloid precursor protein expression were seen in non-gliotic cortex-to-cortex transplants. Compared to host cortex, the levels of both N-terminal and C-terminal fragments of presenilin-1 were significantly lower in gliotic heterotopic grafts.The changes described here largely mirror those seen in the cerebral cortex of humans with Alzheimer's disease and are consistent with the proposal that astrogliosis may be an important factor in the pathogenesis of this disease

  170. Masliah E, Ho G, Wyss-Coray T (2001) Functional role of TGF beta in Alzheimer's disease microvascular injury: lessons from transgenic mice. Neurochem.Int. 39:393-400
    Abstract: Recent studies have implicated pro- and anti-inflammatory cytokines as integral to Alzheimer's disease (AD) pathogenesis. Among them, transforming growth factor-beta (TGF-beta) is emerging as an important factor in regulating inflammatory responses. This multifunctional cytokine might be centrally involved in several aspects of AD pathogenesis by regulating beta-amyloid precursor protein synthesis and processing, plaque formation, astroglial and Microglial response and neuronal cell death. Among all of these potential roles, studies in transgenic and infusion animal models have shown that TGF-beta may primarily contribute to AD pathogenesis by influencing A beta production and deposition, which in turn might result in damage to the brain microvasculature. The lessons learned from these models are of great interest not only for understanding of the role of TGF-beta in AD, but also for future treatments where testing of anti-inflammatory agents such as ibuprofen and an amyloid vaccine hold great promise. In this regard, further elucidation of the signal pathways by which TGF-beta exerts its effect in AD might lead to specific targets for further therapeutic intervention

  171. Matsuoka Y, Picciano M, Malester B, LaFrancois J, Zehr C, Daeschner JM, Olschowka JA, Fonseca MI, O'Banion MK, Tenner AJ, Lemere CA, Duff K (2001) Inflammatory responses to amyloidosis in a transgenic mouse model of Alzheimer's disease. Am.J.Pathol. 158:1345-1354
    Abstract: Mutations in the amyloid precursor protein (APP) and presenilin-1 and -2 genes (PS-1, -2) cause Alzheimer's disease (AD). Mice carrying both mutant genes (PS/APP) develop AD-like deposits composed of beta-amyloid (Abeta) at an early age. In this study, we have examined how Abeta deposition is associated with immune responses. Both fibrillar and nonfibrillar Abeta (diffuse) deposits were visible in the frontal cortex by 3 months, and the amyloid load increased dramatically with age. The number of fibrillar Abeta deposits increased up to the oldest age studied (2.5 years old), whereas there were less marked changes in the number of diffuse deposits in mice over 1 year old. Activated Microglia and astrocytes increased synchronously with amyloid burden and were, in general, closely associated with deposits. Cyclooxygenase-2, an inflammatory response molecule involved in the prostaglandin pathway, was up-regulated in astrocytes associated with some fibrillar deposits. Complement component 1q, an immune response component, strongly colocalized with fibrillar Abeta, but was also up-regulated in some plaque-associated Microglia. These results show: i) an increasing proportion of amyloid is composed of fibrillar Abeta in the aging PS/APP mouse brain; ii) Microglia and astrocytes are activated by both fibrillar and diffuse Abeta; and iii) cyclooxygenase-2 and complement component 1q levels increase in response to the formation of fibrillar Abeta in PS/APP mice

  172. Mattson MP, Camandola S (2001) NF-kappaB in neuronal plasticity and neurodegenerative disorders. J.Clin.Invest 107:247-254

  173. Meda L, Baron P, Scarlato G (2001) Glial activation in Alzheimer's disease: the role of Abeta and its associated proteins. Neurobiol.Aging 22:885-893
    Abstract: A common feature of Alzheimer's disease (AD) pathology is the abundance of reactive astrocytes and activated Microglia in close proximity to neuritic plaques containing amyloid-beta protein (Abeta). The relationship between glial activation and neurodegeneration remains unclear, although several cytokines and inflammatory mediators produced by activated glia have the potential to initiate or exacerbate the progression of neuropathology. Assuming that glial activation plays a central role in the development and progression of AD, a prominent feature is to understand which stimuli drive this activation in senile plaques and to define their effects in vitro. There is a growing body of evidence to suggest that deposition of Abeta and expression of its associated molecules represent important trigger factors in glial activation leading to an inflammatory reaction in the brain. Thus, unraveling the mechanisms by which these proteins exert their effect on glial cells may provide significant insight into the pathophysiology of AD, and may lead to the identification of new strategies for AD treatment

  174. Moreno-Flores MT, Martin-Aparicio E, Salinero O, Wandosell F (2001) Fibronectin modulation by A beta amyloid peptide (25-35) in cultured astrocytes of newborn rat cortex. Neurosci.Lett. 314:87-91
    Abstract: Fibronectin appears to be present in Senile Plaques of Alzheimer's disease brains. These senile or neuritic plaques are surrounded by dystrophic neurites, activated Microglia and reactive astrocytes. The purpose of this work was to establish if a direct correlation exists between the production of Fibronectin (FN) by astrocytes and the presence of amyloid, analysing the modification of this protein produced after the treatment of cultured astrocytes with amyloid peptide (25-35). Our data showed that the addition of previously polymerised A beta-peptide to cultured astrocytes induced a marked increase in FN immunoreactivity that is in part dependent on phosphatases 2A or phosphatase 1, since was partially inhibited by okadaic acid. The increased amount of FN did not appear to be associated to any specific single isoform of which are mainly present in the rat brain. Our data suggest that in vivo FN accumulated in senile plaques may be the result, at least in part, of the response of reactive astrocyte to the presence of amyloid peptide. The importance of FN up-regulation in vivo, as part of a 'positive' response of the astrocytes to produce molecules that favours neurite outgrowth, is discussed

  175. Mrak RE, Griffinbc WS (2001) The role of activated astrocytes and of the neurotrophic cytokine S100B in the pathogenesis of Alzheimer's disease. Neurobiol.Aging 22:915-922
    Abstract: Activated astrocytes, overexpressing the neurotrophic signaling molecule S100beta, are invariant components of the Abeta plaques of Alzheimer's disease. Even early, nonfibrillar amyloid deposits in Alzheimer's disease contain such astrocytes, and the numbers and degree of activation of these wax and wane with the subsequent neuritic pathology of plaque evolution. Astrocytic overexpression of S100B in the neuritic plaques of Alzheimer's disease correlates with the degree of neuritic pathology in Abeta plaques in this disease, suggesting a pathogenic role for S100B's neurotrophic properties in the evolution of these lesions. Astrocytic overexpression of S100B, in turn, is promoted by high levels of interleukin-1 (IL-1), originating from activated Microglia that are also constant components of Abeta plaques in Alzheimer's disease. Similar patterns of astrocyte activation, S100B overexpression, Microglial activation, and IL-1 overexpression are seen in conditions that confer risk for Alzheimer's disease (aging, head trauma, Down's syndrome), in conditions that predispose to accelerated appearance of Alzheimer-like neuropathologic changes (chronic epilepsy, HIV infection), and in animal models of Alzheimer's disease. These cells and molecules are an important components of a cytokine cycle of molecular and cellular cascades that may drive disease progression in Alzheimer's disease

  176. Muehlhauser F, Liebl U, Kuehl S, Walter S, Bertsch T, Fassbender K (2001) Aggregation-Dependent interaction of the Alzheimer's beta-amyloid and Microglia. Clin.Chem.Lab Med. 39:313-316
    Abstract: Chronic glial activation possibly plays a role in chronic neurodegeneration in Alzheimer's disease (AD). It has been shown that amyloid peptide is capable of activating Microglial cells in vitro. The aim of this study was to further characterize the structural preconditions for amyloid peptide in order to activate glial cells and to investigate whether this peptide is also able to induce glial activation in the living brain. We observed that amyloid peptide induced strong cellular activation in primary Microglial cell culture as detected by the release of stable metabolites of nitric oxide (NO), when the peptide was fibrillar. For this activation, co-stimulation with interferon-gamma was a precondition. Using microdialysis of the living brain in a rat we observed pronounced NO generation when fibrillar amyloid peptide was stereotaxically injected. Non-fibrillar amyloid peptide did not induce such a glial reaction. No administration of interferon-gamma or any other co-stimulatory factor was necessary in vivo. Thus, we show that fibrillar, but not non-fibrillar amyloid peptide induced glial activation also in vivo. In the case of the living brain, the presence of deposits of fibrillar amyloid peptide could maintain a chronic Microglial activation, ultimately leading to the progressive neurodegeneration associated with Alzheimer's disease

  177. Nilsson LN, Das S, Potter H (2001) Effect of cytokines, dexamethasone and the A/T-signal peptide polymorphism on the expression of alpha(1)-antichymotrypsin in astrocytes: significance for Alzheimer's disease. Neurochem.Int. 39:361-370
    Abstract: Proinflammatory cytokines and acute phase proteins, such as alpha(1)-antichymotrypsin, are over expressed in Microglia and astrocytes in brain regions with abundant mature amyloid plaques, suggesting a glial cell-led brain acute phase response in the Alzheimer neuropathology. In this paper, we show that alpha(1)-antichymotrypsin gene expression in human astrocytes is elevated by interleukin-1 and interleukin-6, and further enhanced by glucocorticoid, while the homologous contrapsin gene in rat astrocytes is unaffected by these cytokines. These distinct gene regulation mechanisms might help to explain the differential susceptibility of humans and rodents to amyloid formation of the Alzheimer's type. In addition, we demonstrate that the alpha(1)-antichymotrypsin A-allele that encodes a different signal peptide and is a suggested risk factor for Alzheimer's disease gives rise to a reduced level of immature alpha(1)-antichymotrypsin in transfected cells. The physiological result would be an enhanced ability of the A-encoded alpha(1)-antichymotrypsin protein to become secreted and promote extracellular amyloid formation. We discuss our findings in terms of a model in which cytokine-induced alpha(1)-antichymotrypsin synthesis in astrocytes constitutes a specific inflammatory pathway that accelerates the development of Alzheimer's disease and could at least partly underlie the regional specificity and species restriction of the neuropathology

  178. Petegnief V, Saura J, Gregorio-Rocasolano N, Paul SM (2001) Neuronal injury-induced expression and release of apolipoprotein E in mixed neuron/glia co-cultures: nuclear factor kappaB inhibitors reduce basal and lesion-induced secretion of apolipoprotein E. Neuroscience 104:223-234
    Abstract: In order to better delineate the intracellular signaling pathways underlying glial apolipoprotein E (apoE) expression and release, we have characterized an in vitro model of induction of glial apoE production induced by neuronal death. Exposure of mixed fetal cortical neuron/glia co-cultures to the neurotoxin N-methyl-D-aspartate results in increased apoE expression and release in a time- and concentration-dependent manner. Increased expression of apoE messenger RNA precedes the increase in intracellular apoE, followed by accumulation of the holoprotein in the culture medium. Neuronal injury induced by N-methyl-D-aspartate is accompanied by a reactive astrogliosis as measured by an increase in glial fibrillary acidic protein messenger RNA and protein at 48 and 72h post-lesion, respectively. A similar microgliosis was observed using the Microglial marker ED-1. Neuronal injury-induced glial apoE secretion is attenuated by the nuclear factor kappaB inhibitors, aspirin, Bay 11-7082 and MG-132, suggesting that this transcription factor is involved in both constitutive and induced glial apoE expression.The present data show that up-regulation of apoE is an early event in the glial activation triggered by neurodegeneration in vitro and that activation of nuclear factor kappaB directly or indirectly mediates the increase in apoE expression

  179. Picklo MJ, Sr., Olson SJ, Hayes JD, Markesbery WR, Montine TJ (2001) Elevation of AKR7A2 (succinic semialdehyde reductase) in neurodegenerative disease. Brain Res. 916:229-238
    Abstract: Elevated levels of oxidative stress or decreased antioxidant defense mechanisms may underlie the regionally increased oxidative damage to brain observed in many neurodegenerative disorders. Phase I detoxification pathways for reactive aldehydes generated from lipid peroxidation include aldehyde dehydrogenases, alcohol dehydrogenases and aldo-keto reductases (AKR). In the present study, we examined the cellular expression of AKR family member, succinic semialdehyde reductase (AKR7A2) that reduces toxic aldehydes as well as catalyzing the biosynthesis of the neuromodulator gamma-hydroxybutyrate (GHB). Our results show that in the cerebral cortex and hippocampus, AKR7A2 is primarily localized to glial cells, astrocytes and Microglia. In the midbrain, AKR7A2 was found in glia and neuromelanin-containing neurons of the substantia nigra, and the periaqueductal gray. In sections of cerebral cortex and hippocampus from patients with AD and DLB, AKR7A2 immunoreactivity was elevated in reactive astrocytes and Microglial cells. Furthermore, total AKR7A2 protein levels were elevated in the cerebral cortex of patients with AD versus control individuals. Our data suggest that reactive gliosis, as a response to injury, may affect GHB neuromodulatory pathways in neurodegenerative disease and elevate aldehyde detoxification pathways

  180. Platt B, Fiddler G, Riedel G, Henderson Z (2001) Aluminium toxicity in the rat brain: histochemical and immunocytochemical evidence. Brain Res.Bull. 55:257-267
    Abstract: Although the neurotoxic actions of aluminium (Al) have been well documented, its contribution to neurodegenerative diseases such as Alzheimer's disease remains controversial. In the present study, we applied histochemical techniques to identify changes induced by intracerebroventricular Al injections (5.4 microg in 5.5 microl, daily over a period of 5 successive days) in the adult rat brain after survival periods of either 1 or 6 weeks. For both Al- and saline-infused controls, no major signs of gross histological changes were evident in cresyl violet-stained sections. Al (as indicated by the fluorescent Morin staining) was concentrated in white matter of the medial striatum, corpus callosum, and cingulate bundle. Immunoreactivity of astrocytes and phagocytic Microglia based on glial fibrillary acidic protein and ED1 markers, respectively, revealed a greater inflammatory response in Al-injected animals compared to controls. Damage of the cingulate bundle in Al-treated animals led to a severe anterograde degeneration of cholinergic terminals in cortex and hippocampus, as indicated by acetylcholinesterase labelling. Our data suggest that the enhancement of inflammation and the interference with cholinergic projections may be the modes of action through which Al may cause learning and memory deficits, and contribute to pathological processes in Alzheimer's disease

  181. Pocock JM, Liddle AC (2001) Microglial signalling cascades in neurodegenerative disease. Prog.Brain Res. 132:555-565
    Abstract: Activated Microglia release a number of substances, the specific cocktail released depending on the stimulus. Many of the substances released by Microglia also serve to activate them, suggesting the presence of a number of autocrine/paracrine loops. Because of the low density of Microglia present in the normal brain, such autocrine/paracrine loops may not be significant but during the initiation and ongoing states of neurodegeneration, the increased concentrations of Microglia may allow the activation and escalated stimulation of these feedback pathways. The activation of p38 MAPK by A beta and cytokines may be part of a Microglial autocrine loop which results in the fueling of the Microglial inflammatory response. A novel class of cytokine suppressive anti-inflammatory drugs (CSAIDs) inhibit the activation of p38 kinase (Bhat et al., 1998) suggesting this kinase plays a key role in transducing Microglial responses to activation stimuli (Badger et al., 1996)

  182. Potter H, Wefes IM, Nilsson LN (2001) The inflammation-induced pathological chaperones ACT and apo-E are necessary catalysts of Alzheimer amyloid formation. Neurobiol.Aging 22:923-930
    Abstract: Biochemical, genetic, and epidemiological evidence indicates that inflammation is an essential part of the pathogenesis of Alzheimer's disease. Over the last decade, we and others have focused on the mechanism by which specific inflammatory molecules contribute to the Alzheimer pathogenic pathway. In particular, we have learned that several acute phase/inflammatory molecules, specifically alpha(1)-antichymotrypsin (ACT) and apolipoprotein E (apoE) that are overproduced in the AD brain can promote the formation of, and are associated with, the neurotoxic amyloid deposits that are a key pathological hallmark of the disease. Because both of these proteins bind to the Abeta peptide and catalyze its polymerization into amyloid filaments, they have been termed "pathological chaperones".ACT, and, to a lesser extent, apoE are greatly overproduced only in areas of the AD brain that are prone to amyloid formation. This restriction suggests a local inflammatory reaction may underlie the regional specificity of amyloid deposition by inducing the production of pathological chaperones. The data that will be discussed indicate that ACT over-expression is caused by the activation of ACT mRNA synthesis in astrocytes in response to increased production of the inflammatory cytokine IL-1. IL-1 is released from Microglia that become activated by pre-amyloid seeds of Abeta. Recently, this inflammatory cascade has been extended to include the amyloid precursor protein (APP), for IL-1 also upregulates the production of APP in astrocytes, but at the translational rather that the transcriptional level. Thus many of the key elements of the Alzheimer's disease pathogenic pathway are products of a local inflammatory reaction in the brain.Further support for a mechanistic role of inflammation in the Alzheimer's disease pathogenic pathway has been provided by genetic studies, which have associated an increased risk of developing AD with specific polymorphisms in the apoE, ACT, and the IL-1 genes. Most recently, transgenic mouse models of AD have demonstrated that ACT and apoE are amyloid promoters/pathological chaperones in vivo whose contribution is necessary for both amyloid formation and for amyloid-associated cognitive decline and memory loss.The importance of these findings is that they help to place inflammation at the center of the pathogenic pathway to Alzheimer's disease and identify specific steps in the pathway that may be amenable to therapeutic intervention

  183. Rempel H, Kusdra L, Pulliam L (2001) Interleukin-1beta up-regulates expression of neurofilament light in human neuronal cells. J.Neurochem. 78:640-645
    Abstract: Elevated expression of interleukin-1 (IL-1beta), a pro-inflammatory cytokine secreted by activated Microglia, is a pathogenic marker of numerous neurodegenerative processes including Alzheimer's disease (AD). We have characterized a link between IL-1beta and the 68-kDa neurofilament light (NF-L) protein, which is a major component of the neuronal cytoskeleton. Using human brain aggregate cultures, we found that IL-1beta treatment significantly increased NF-L expression in primary neurons. Analysis of mRNA levels demonstrated elevated NF-L expression within 72 h while imaging of neurons by immunofluorescent staining for NF-L confirmed IL-1beta-induced NF-L protein expression. These observations suggest a potential inflammatory-induced mechanism for deregulation of an important cytoskeletal protein, NF-L, possibly leading to neuronal dysfunction

  184. Rogers J, Lue LF (2001) Microglial chemotaxis, activation, and phagocytosis of amyloid beta-peptide as linked phenomena in Alzheimer's disease. Neurochem.Int. 39:333-340
    Abstract: Microglia are widely held to play important pathophysiologic roles in Alzheimer's disease (AD). On exposure to amyloid beta peptide (A beta) they exhibit chemotactic, phagocytic, phenotypic and secretory responses consistent with scavenger cell activity in a localized inflammatory setting. Because AD Microglial chemotaxis, phagocytosis, and secretory activity have common, tightly linked soluble intermediaries (e.g., cytokines, chemokines), cell surface intermediaries (e.g., receptors, opsonins), and stimuli (e.g., highly inert A beta deposits and exposed neurofibrilly tangles), the mechanisms for Microglial clearance of A beta are necessarily coupled to localized inflammatory mechanisms that can be cytotoxic to nearby tissue. This presents a critical dilemma for strategies to remove A beta by enhancing micoglial activation--a dilemma that warrants substantial further investigation

  185. Schubert P, Ogata T, Marchini C, Ferroni S (2001) Glia-related pathomechanisms in Alzheimer's disease: a therapeutic target? Mech.Ageing Dev. 123:47-57
    Abstract: Reactive glial cell properties could contribute to pathomechanisms underlying Alzheimer's disease by favoring oxidative neuronal damage and beta-amyloid toxicity. A critical step is apparently reached when pathological glia activation is no longer restricted to Microglia and includes astrocytes. By giving up their differentiated state, astrocytes may lose their physiological negative feed-back control on Microglial NO production and even contribute to neurotoxic peroxynitrate formation. Another consequence is the impairment of the astrocyte-maintained extracellular ion homeostasis favoring excitotoxic damage. By the production of apolipoprotein-E, triggered by the Microglial cytokine interleukine-1beta, reactive astrocytes could promote the transformation of beta-amyloid into the toxic form. A pharmacologically reinforced cAMP signaling in rat glial cell cultures depressed oxygen radical formation in Microglia and their release of TNF-alpha and interleukine-1beta, feed-forward signals which mediate oxidative damage and secondary astrocyte activation. Cyclic AMP also favored differentiation and expression of a mature ion channel pattern in astrocytes improving their glutamate buffering. A deficient cholinergic signaling that increases the risk of pathological APP processing was compensated by an adenosine-mediated reinforcement of the second messenger calcium. A combination therapy with acetylcholine-esterase inhibitors together with adenosine raising pharmaca, therefore, may be used to treat cholinergic deficiency in Alzheimer's disease

  186. Sheng JG, Jones RA, Zhou XQ, McGinness JM, Van Eldik LJ, Mrak RE, Griffin WS (2001) Interleukin-1 promotion of MAPK-p38 overexpression in experimental animals and in Alzheimer's disease: potential significance for tau protein phosphorylation. Neurochem.Int. 39:341-348
    Abstract: Activated (phosphorylated) mitogen-activated protein kinase p38 (MAPK-p38) and interleukin-1 (IL-1) have both been implicated in the hyperphosphorylation of tau, a major component of the neurofibrillary tangles in Alzheimer's disease. This, together with findings showing that IL-1 activates MAPK-p38 in vitro and is markedly overexpressed in Alzheimer brain, suggest a role for IL-1-induced MAPK-p38 activation in the genesis of neurofibrillary pathology in Alzheimer's disease. We found frequent colocalization of hyperphosphorylated tau protein (AT8 antibody) and activated MAPK-p38 in neurons and in dystrophic neurites in Alzheimer brain, and frequent association of these structures with activated Microglia overexpressing IL-1. Tissue levels of IL-1 mRNA as well as of both phosphorylated and non-phosphorylated isoforms of tau were elevated in these brains. Significant correlations were found between the numbers of AT8- and MAPK-p38-immunoreactive neurons, and between the numbers of activated Microglia overexpressing IL-1 and the numbers of both AT8- and MAPK-p38-immunoreactive neurons. Furthermore, rats bearing IL-1-impregnated pellets showed a six- to seven-fold increase in the levels of MAPK-p38 mRNA, compared with rats with vehicle-only pellets (P<0.0001). These results suggest that Microglial activation and IL-1 overexpression are part of a feedback cascade in which MAPK-p38 overexpression and activation leads to tau hyperphosphorylation and neurofibrillary pathology in Alzheimer's disease

  187. Sigurdsson EM, Scholtzova H, Mehta PD, Frangione B, Wisniewski T (2001) Immunization with a nontoxic/nonfibrillar amyloid-beta homologous peptide reduces Alzheimer's disease-associated pathology in transgenic mice. Am.J.Pathol. 159:439-447
    Abstract: Transgenic mice with brain amyloid-beta (Abeta) plaques immunized with aggregated Abeta1-42 have reduced cerebral amyloid burden. However, the use of Abeta1-42 in humans may not be appropriate because it crosses the blood brain barrier, forms toxic fibrils, and can seed fibril formation. We report that immunization in transgenic APP mice (Tg2576) for 7 months with a soluble nonamyloidogenic, nontoxic Abeta homologous peptide reduced cortical and hippocampal brain amyloid burden by 89% (P = 0.0002) and 81% (P = 0.0001), respectively. Concurrently, brain levels of soluble Abeta1-42 were reduced by 57% (P = 0.0019). Ramified Microglia expressing interleukin-1beta associated with the Abeta plaques were absent in the immunized mice indicating reduced inflammation in these animals. These promising findings suggest that immunization with nonamyloidogenic Abeta derivatives represents a potentially safer therapeutic approach to reduce amyloid burden in Alzheimer's disease, instead of using toxic Abeta fibrils

  188. Silva I, Mor G, Naftolin F (2001) Estrogen and the aging brain. Maturitas 38:95-100
    Abstract: Evidence is presented indicating a role for estrogen in the function and maintenance of the aging brain. Based on complementary data that estrogen regulates the function of the immune--brain barrier, the hypothesis is presented that estrogen contributes to brain homeostasis via regulation of Microglial activation, enabling immune-privileged status in the brain. Diminished estrogen levels during the menopause compromise the immune--brain barrier fostering inflammatory processes in the brain. This has potentially lethal consequences for brain cells, and may contribute to brain pathologies such as Alzheimer's disease

  189. Skovronsky DM, Fath S, Lee VM, Milla ME (2001) Neuronal localization of the TNFalpha converting enzyme (TACE) in brain tissue and its correlation to amyloid plaques. J.Neurobiol. 49:40-46
    Abstract: The tumor necrosis factor (TNF)-alpha converting enzyme (TACE) can cleave the cell-surface ectodomain of the amyloid-beta precursor protein (APP), thus decreasing the generation of amyloid-beta (Abeta) by cultured non-neuronal cells. While the amyloidogenic processing of APP in neurons is linked to the pathogenesis of Alzheimer's disease (AD), the expression of TACE in neurons has not yet been examined. Thus, we assessed TACE expression in a series of neuronal and non-neuronal cell types by Western blots. We found that TACE was present in neurons and was only faintly detectable in lysates of astrocytes, oligodendrocytes, and Microglial cells. Immunohistochemical analysis was used to determine the cellular localization of TACE in the human brain, and its expression was detected in distinct neuronal populations, including pyramidal neurons of the cerebral cortex and granular cell layer neurons in the hippocampus. Very low levels of TACE were seen in the cerebellum, with Purkinje cells at the granular-molecular boundary staining faintly. Because TACE was localized predominantly in areas of the brain that are affected by amyloid plaques in AD, we examined its expression in a series of AD brains. We found that AD and control brains showed similar levels of TACE staining, as well as similar patterns of TACE expression. By double labeling for Abeta plaques and TACE, we found that TACE-positive neurons often colocalized with amyloid plaques in AD brains. These observations support a neuronal role for TACE and suggest a mechanism for its involvement in AD pathogenesis as an antagonist of Abeta formation

  190. Stalder M, Deller T, Staufenbiel M, Jucker M (2001) 3D-Reconstruction of Microglia and amyloid in APP23 transgenic mice: no evidence of intracellular amyloid. Neurobiol.Aging 22:427-434
    Abstract: Microglia cells are closely associated with compact amyloid plaques in Alzheimer's disease (AD) brains. Although activated Microglia seem to play a central role in the pathogenesis of AD, mechanisms of Microglial activation by beta-amyloid as well as the nature of interaction between amyloid and Microglia remain poorly understood. We previously reported a close morphological association between activated Microglia and congophilic amyloid plaques in the brains of APP23 transgenic mice at both the light and electron microscopic levels [25]. In the present study, we have further examined the structural relationship between Microglia and amyloid deposits by using postembedding immunogold labeling, serial ultrathin sectioning, and 3-dimensional reconstruction. Although bundles of immunogold-labeled amyloid fibrils were completely engulfed by Microglial cytoplasm on single sections, serial ultrathin sectioning and three-dimensional reconstruction revealed that these amyloid fibrils are connected to extracellular amyloid deposits. These data demonstrate that extracellular amyloid fibrils form a myriad of finger-like channels with the widely branched Microglial cytoplasm. We conclude that in APP23 mice a role of Microglia in amyloid phagocytosis and intracellular production of amyloid is unlikely

  191. Streit WJ, Conde JR, Harrison JK (2001) Chemokines and Alzheimer's disease. Neurobiol.Aging 22:909-913
    Abstract: In recent years, increasing attention has been focused on chemokines as inflammatory mediators in the CNS. The limited number of studies that have investigated chemokine and chemokine receptor expression in Alzheimer's disease (AD) brain and in cell culture models seem to support a role for inflammation in AD pathogenesis. Here we provide a review of these studies, but in addition, point out the possible role of chemokines as communication molecules between neurons and Microglia. Understanding neuron-Microglia interactions is essential for understanding AD pathogenesis, and disturbances in chemokine-mediated intercellular communication may contribute toward a generalized impairment of Microglial cell function

  192. Szczepanik AM, Funes S, Petko W, Ringheim GE (2001) IL-4, IL-10 and IL-13 modulate A beta(1--42)-induced cytokine and chemokine production in primary murine Microglia and a human monocyte cell line. J.Neuroimmunol. 113:49-62
    Abstract: A hallmark of the immunopathology associated with Alzheimer's disease (AD) is the presence of activated Microglia surrounding senile plaque deposits of beta-amyloid (A beta) peptides. A beta peptides have been shown to be potent activators of Microglia and macrophages, but little is known about endogenous factors that may modulate their responses to amyloid. We investigated whether the 'anti-inflammatory' cytokines IL-4, IL-10 and IL-13 could regulate A beta-induced production of the inflammatory cytokines IL-1 alpha, IL-1 beta, TNF-alpha, IL-6 and the chemokine MCP-1. A beta(1-42) time- and dose-dependently induced the production and secretion of these inflammatory proteins in the human THP-1 monocyte cell line and in primary murine Microglia, similar to what was observed for lipopolysaccharide (LPS) stimulated cells. IL-10 was found to suppress all A beta and LPS-induced inflammatory proteins measured (IL-1 alpha, IL-1 beta, IL-6, TNF-alpha and MCP-1) in both cell types with the exception of LPS-induced MCP-1 in THP-1 cells where no change was observed. In contrast to the inhibition observed for IL-10, both IL-4 and IL-13 enhanced MCP-1 secretion. IL-4 and IL-13 reduced IL-6 secretion, but effects on IL-1 alpha, IL-1 beta or TNF-alpha were dependent on cell type and stimulus conditions. Additional experiments using RT-PCR showed that IL-4, IL-10 and IL-13 mRNA is found to be present in human brain tissue. These results show that IL-4, IL-10, and IL-13 differentially regulate Microglial responses to A beta and may play a role in the inflammation pathology observed surrounding senile plaques

  193. Szpak GM, Lechowicz W, Lewandowska E, Bertrand E, Wierzba-Bobrowicz T, Gwiazda E, Schmidt-Sidor B, Dymecki J (2001) Neurones and Microglia in central nervous system immune response to degenerative processes. Part 1: Alzheimer's disease and Lewy body variant of Alzheimer's disease. Quantitative study. Folia Neuropathol. 39:181-192
    Abstract: The quantitative correlation between neurone loss and brain immune response, assessed by intensity of Microglia inflammatory reaction in cortical association area and limbic cortex, was investigated and compared in previously immunohistochemistry (IHC) and ultrastructural confirmed 11 cases of Alzheimer's disease (AD), 7 cases mixed form of Dementia with AD findings and Lewy bodies (AD/DLB) reported, in accordance with Consortium on Dementia, as Lewy body variant of AD (LBV) and 6 non-demented autopsy control cases from 63 to 86 years old. In the present work we investigated association and limbic cortical areas linked with memory mechanisms; there are regions characterised by early distribution of IHC confirmed AD and DLB/AD (LBV) markers, as well as a substantial physiological stability of neurone pool regardless of age. The results indicated that AD and LBV differ in their neurone loss intensity and inflammatory reaction, with much higher intensity in AD. In Alzheimer's disease, neurone loss in association temporal cortex made up 51% of control values with simultaneous 8-fold increase in the density of MHC II-positive activated Microglia, whereas in LBV, both the loss of neurone density and the increase in activated Microglia density, was not so high (up to 41% and 4-5-fold, respectively). Changes in the limbic cortex were less pronounced. A strong correlation in the clinical material between neurone loss and Microglia activation in both processes, especially in AD (r = 0.73), speaks in favour of the hypothesis on the neuronal immune surveillance and arousal of immune brain response in conditions of declining control, due to significant neurone loss in the neurodegenerative process. The inflammatory reaction of MHC II-immunoreactive Microglia, concomitant with neurodegenerative process, seems to be a consequence of increased immune response due to loss of neurones and weakening of their control upon immunosurveillance in central nervous system

  194. Takeda A, Wakai M, Niwa H, Dei R, Yamamoto M, Li M, Goto Y, Yasuda T, Nakagomi Y, Watanabe M, Inagaki T, Yasuda Y, Miyata T, Sobue G (2001) Neuronal and glial advanced glycation end product [Nepsilon-(carboxymethyl)lysine]] in Alzheimer's disease brains. Acta Neuropathol.(Berl) 101:27-35
    Abstract: The cellular distribution of an advanced glycation end product [Nepsilon-(carboxymethyl)lysine (CML)] in aged and Alzheimer's disease (AD) brains was assessed immunohistochemically. CML was localized in the cytoplasm of neurons, astrocytes, and Microglia in both aged and AD brains. Glial deposition was far more marked in AD brains than in aged brains, and neuronal deposition was also increased. On electron microscopic immunohistochemistry, neuronal CML formed granular or linear deposits associated with lipofuscin, and glial deposits formed lines around the vacuoles. Neuronal and glial deposits were prominent throughout the cerebral cortex and hippocampus, but were sparse in the putamen, globus pallidus, substantia nigra, and cerebellum, with glial deposits being far more prominent in AD brains. The distribution of neuronal and glial deposits did not correspond with the distribution of AD pathology. The extent of CML deposits was inversely correlated with neurofibrillary tangle formation, particularly in the hippocampus. Most hippocampal pyramidal neurons with neurofibrillary tangles did not have CML, and most of the neurons with heavy CML deposits did not have neurofibrillary tangles. In the hippocampus, neuronal CML was prominent in the region where neuronal loss was mild. These observations suggest that CML deposition does not directly cause neurofibrillary tangle formation or neuronal loss in AD

  195. Tarkowski E, Wallin A, Regland B, Blennow K, Tarkowski A (2001) Local and systemic GM-CSF increase in Alzheimer's disease and vascular dementia. Acta Neurol.Scand. 103:166-174
    Abstract: A growing body of evidence points out the potential role of inflammatory mechanisms in the pathophysiology of brain damage in dementia. The aim of the present study was to investigate patterns of local and systemic cytokine release in patients with Alzheimer's disease (AD) and vascular dementia (VAD). The intrathecal levels of cytokines were related to neuronal damage and cerebral apoptosis. Twenty patients with early AD and 26 patients with VAD were analyzed with respect to cerebrospinal fluid (CSF) and serum levels of pro- and anti-inflammatory cytokines. In addition, CSF levels of Fas/APO-1 and bcl-2, a measure for apoptosis, and Tau protein, a marker for neuronal degradation, were studied. Significantly increased CSF levels of GM-CSF but not of other cytokines were observed in both dementia groups. These patients displayed a significant correlation between the GM-CSF levels and the levels of Fas/APO-1 and Tau protein in CSF. Our study demonstrates an intrathecal production of GM-CSF, a cytokine stimulating Microglial cell growth and exerting inflammatogenic properties. It is suggested that GM-CSF once secreted induces programmed cell death in the brain tissue of patients with dementia

  196. Town T, Tan J, Mullan M (2001) CD40 signaling and Alzheimer's disease pathogenesis. Neurochem.Int. 39:371-380
    Abstract: The interaction between CD40 and its cognate ligand, CD40 ligand, is a primary regulator of the peripheral immune response, including modulation of T lymphocyte activation, B lymphocyte differentiation and antibody secretion, and innate immune cell activation, maturation, and survival. Recently, we and others have identified CD40 expression on a variety of CNS cells, including endothelial cells, smooth muscle cells, astroglia and Microglia, and have found that, on many of these cells, CD40 expression is enhanced by pro-inflammatory stimuli. Importantly, the CD40-CD40 ligand interaction on Microglia triggers a series of intracellular signaling events that are discussed, beginning with Src-family kinase activation and culminating in Microglial activation as evidenced by tumor necrosis factor-alpha secretion. Based on the involvement of Microglial activation and brain inflammation in Alzheimer's disease pathogenesis, we have investigated co-stimulation of Microglia, smooth muscle, and endothelial cells with CD40 ligand in the presence of low doses of freshly solubilized amyloid-beta peptides. Data reviewed herein show that CD40 ligand and amyloid-beta act synergistically to promote pro-inflammatory responses by these cells, including secretion of interleukin-1 beta by endothelial cells and tumor necrosis factor-alpha by Microglia. As these cytokines have been implicated in neuronal injury, a comprehensive model of pro-inflammatory CD40 ligand and amyloid-beta initiated Alzheimer's disease pathogenesis (mediated by multiple CNS cells) is proposed

  197. Viel JJ, McManus DQ, Smith SS, Brewer GJ (2001) Age- and concentration-dependent neuroprotection and toxicity by TNF in cortical neurons from beta-amyloid. J.Neurosci.Res. 64:454-465
    Abstract: The induction of an inflammatory response and release of cytokines such as TNF may be involved in the age-related etiology of Alzheimer disease (AD). In the brain, Microglia have been shown to produce a wide variety of immune mediators, including the pro-inflammatory cytokine tumor necrosis factor (TNF). We hypothesize that with age there is increased ability of Microglia to produce TNF or that age decreases the neuroprotective effect of TNF against beta-amyloid (Abeta) toxicity in neurons. We investigated the effects of Abeta(1-40) on TNF secretion from forebrain cultures of Microglia from embryonic, middle-age (9-month) and old (36-month) rats. Over the first 12 hr of exposure to 10 microM Abeta (1-40), Microglia from embryonic and old rats increase TNF secretion, although Microglia from middle-age rats did not produce detectable levels of TNF. When low concentrations of TNF are added to neurons together with Abeta (1-40) in the absence of exogenous antioxidants, neuroprotection for old neurons is significantly less than neuroprotection for middle-age neurons. In neurons from old rats, high levels of TNF together with Abeta are more toxic than in neurons from middle-age or embryonic rats. These results are discussed in relation to neuroprotection and toxicity of the age-related pathology of AD

  198. von Bernhardi R, Ramirez G (2001) Microglia-astrocyte interaction in Alzheimer's disease: friends or foes for the nervous system? Biol.Res. 34:123-128
    Abstract: Brain glial cells secrete several molecules that can modulate the survival of neurons after various types of damage to the CNS. Activated Microglia and astrocytes closely associate to amyloid plaques in Alzheimer Disease (AD). They could have a role in the neurotoxicity observed in AD because of the inflammatory reaction they generate. There is controversy regarding the individual part played by the different glial cells, and the interrelationships between them. Both astrocytes and Microglia produce several cytokines involved in the inflammatory reaction. Moreover, the same cytokines may have different effects, depending on their concentration and the type of cells in the vicinity. In turn, the events occurring in response to injury may lead to changes in the nature and relative concentration of the various factors involved. To learn about these putative glial interrelationships, we examined some effects of astrocytes on Microglial activation

  199. Walker DG, Lue LF, Beach TG (2001) Gene expression profiling of amyloid beta peptide-stimulated human post-mortem brain Microglia. Neurobiol.Aging 22:957-966
    Abstract: Activation of Microglia is a central part of the chronic inflammatory processes in Alzheimer's disease (AD). In the brains of AD patients, activated Microglia are associated with amyloid beta (Abeta) peptide plaques. A number of previous studies have shown that aggregated synthetic Abeta peptide activates cultured Microglia to produce a range inflammatory products. The full extent of the inflammatory response still remains to be determined. In this study, gene array technology was employed to investigate in a more extensive manner the consequences of Microglial activation by Abeta peptide. RNA was prepared from pooled samples of cortical human Microglia isolated from post-mortem cases and incubated with a low dose (2.5 microM) of Abeta1-42 (or peptide solvent) for 24 h. This material was used to prepare cDNA probes, which were used to detect the differential pattern of expressed genes on a 1,176 Clontech membrane gene array. Results obtained showed that 104 genes were either upregulated or downregulated by 1.67 fold or greater. The most highly induced genes belonged to the chemokine family with interleukin-8 (IL-8) expression being increased by 11.7 fold. Interestingly, many of the highly induced genes had been identified as being responsive to activation by the transcription factor NF-kappaB. A number of genes were downregulated. Thymosin beta, prothymosin alpha and parathymosin, all belonging to the same gene family, were downregulated. To validate these semi-quantitative results, the expression of intercellular adhesion molecule-1 (ICAM-1) and rhoB were measured by RT-PCR in samples of cDNA derived from Abeta and control stimulated human cortical Microglia. These results confirm the usefulness of the gene array approach for studying Abeta-mediated inflammatory processes

  200. Wegiel J, Wang KC, Imaki H, Rubenstein R, Wronska A, Osuchowski M, Lipinski WJ, Walker LC, LeVine H (2001) The role of Microglial cells and astrocytes in fibrillar plaque evolution in transgenic APP(SW) mice. Neurobiol.Aging 22:49-61
    Abstract: Ultrastructural reconstruction of 27 fibrillar plaques in different stages of formation and maturation was undertaken to characterize the development of fibrillar plaques in the brains of human APP(SW) transgenic mice (Tg2576). The study suggests that Microglial cells are not engaged in Abeta removal and plaque degradation, but in contrast, are a driving force in plaque formation and development. Fibrillar Abeta deposition at the amyloid pole of Microglial cells appears to initiate three types of neuropil response: degeneration of neurons, protective activation of astrocytes, and attraction and activation of Microglial cells sustaining plaque growth. Enlargement of neuronal processes and synapses with accumulation of degenerated mitochondria, dense bodies, and Hirano-type bodies is the marker of toxic injury of neurons by fibrillar Abeta. Separation of amyloid cores from neurons and degradation of amyloid cores by cytoplasmic processes of hypertrophic astrocytes suggest the protective and defensive character of astrocytic response to fibrillar Abeta. The growth of cored plaque from a small plaque with one Microglial cell with an amyloid star and a few dystrophic neurites to a large plaque formed by several dozen Microglial cells seen in old mice is the effect of attraction and activation of Microglial cells residing outside of the plaque perimeter. This mechanism of growth of plaques appears to be characteristic of cored plaques in transgenic mice. Other features in mouse Microglial cells that are absent in human brain are clusters of vacuoles, probably of lysosomal origin. They evolve into circular cisternae and finally into large vacuoles filled with osmiophilic, amorphous material and bundles of fibrils that are poorly labeled with antibody to Abeta. Microglial cells appear to release large amounts of fibrillar Abeta and accumulate traces of fibrillar Abeta in a lysosomal pathway

  201. Wilcock DM, Gordon MN, Ugen KE, Gottschall PE, DiCarlo G, Dickey C, Boyett KW, Jantzen PT, Connor KE, Melachrino J, Hardy J, Morgan D (2001) Number of Abeta inoculations in APP+PS1 transgenic mice influences antibody titers, Microglial activation, and congophilic plaque levels. DNA Cell Biol. 20:731-736
    Abstract: There have been several reports on the use of beta-amyloid (Abeta ) vaccination in different mouse models of Alzheimer's disease (AD) and its effects on pathology and cognitive function. In this report, the histopathologic findings in the APP+PS1 doubly transgenic mouse were compared after three, five, or nine Abeta inoculations. The number of inoculations influenced the effects of vaccination on Congo red levels, Microglia activation, and anti-Abeta antibody titers. After three inoculations, the antibody titer of transgenic mice was substantially lower than that found in nontransgenic animals. However, after nine inoculations, the levels were considerably higher in both genotypes and no longer distinguishable statistically. The number of inoculations influenced CD45 expression, an indicator of Microglial activation. There was an initial upregulation, which was significant after five inoculations, but by nine inoculations, the extent of Microglial activation was equivalent to that in mice given control vaccinations. Along with this increased CD45 expression, there was a correlative reduction in staining by Congo red, which stains compact plaques. When data from the mice from all groups were combined, there was a significant correlation between activation of Microglia and Congo red levels, suggesting that Microglia play a role in the clearance of compact plaque

  202. Wilms H, Rosenstiel P, Sievers J, Deuschl G, Lucius R (2001) Cerebrospinal fluid from patients with neurodegenerative and neuroinflammatory diseases: no evidence for rat glial activation in vitro. Neurosci.Lett. 314:107-110
    Abstract: To determine the possible contribution of glial cells via oxidative stress/cytokine secretion in the pathogenesis of Parkinson's disease (PD), Alzheimer disease (AD), amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS) the concentration of nitric oxide (NO) (by the Griess method) and Interleukin-6 (IL-6) (by enzyme-linked immunosorbent assay) were measured in resting rat Microglial and astrocytic cell culture supernatants stimulated by cerebrospinal fluid (CSF) (dilution 1:4, 1:10) from patients with the aforementioned diseases. Neither the concentration of NO (optical density at 450 nm: control, 0.036+/-0.006; MS, 0.034+/-0.008; AD, 0.031+/-0.006; PD, 0.02+/-0.01; lipopolysaccharide (LPS), 0.26+/-0.018) nor the amount of IL-6 (ng/ml: control, 0.112+/-0.026; PD, 0.12+/-0.027; MS, 0.123+/-0.008; ALS, 0.137+/-0.01; LPS, 1.81+/-0.11) differed in any disease group from those of unaffected controls. These findings suggest that the stimuli for inflammatory activation of glia are quite localized and not present in sufficient concentrations in the CSF of affected patients

  203. Wong A, Luth HJ, Deuther-Conrad W, Dukic-Stefanovic S, Gasic-Milenkovic J, Arendt T, Munch G (2001) Advanced glycation endproducts co-localize with inducible nitric oxide synthase in Alzheimer's disease. Brain Res. 920:32-40
    Abstract: Advanced glycation endproducts (AGEs), protein-bound oxidation products of sugars, have been shown to be involved in the pathophysiological processes of Alzheimer's disease (AD). AGEs induce the expression of various pro-inflammatory cytokines and the inducible nitric oxide synthase (iNOS) leading to a state of oxidative stress. AGE modification and resulting crosslinking of protein deposits such as amyloid plaques may contribute to the oxidative stress occurring in AD. The aim of this study was to immunohistochemically compare the localization of AGEs and beta-amyloid (Abeta) with iNOS in the temporal cortex (Area 22) of normal and AD brains. In aged normal individuals as well as early stage AD brains (i.e. no pathological findings in isocortical areas), a few astrocytes showed co-localization of AGE and iNOS in the upper neuronal layers, compared with no astrocytes detected in young controls. In late AD brains, there was a much denser accumulation of astrocytes co-localized with AGE and iNOS in the deeper and particularly upper neuronal layers. Also, numerous neurons with diffuse AGE but not iNOS reactivity and some AGE and iNOS-positive Microglia were demonstrated, compared with only a few AGE-reactive neurons and no Microglia in controls. Finally, astrocytes co-localized with AGE and iNOS as well as AGE and were found surrounding mature but not diffuse amyloid plaques in the AD brain. Our results show that AGE-positive astrocytes and Microglia in the AD brain express iNOS and support the evidence of an AGE-induced oxidative stress occurring in the vicinity of the characteristic lesions of AD. Hence activation of Microglia and astrocytes by AGEs with subsequent oxidative stress and cytokine release may be an important progression factor in AD

  204. Wong A, Dukic-Stefanovic S, Gasic-Milenkovic J, Schinzel R, Wiesinger H, Riederer P, Munch G (2001) Anti-inflammatory antioxidants attenuate the expression of inducible nitric oxide synthase mediated by advanced glycation endproducts in murine Microglia. Eur.J.Neurosci. 14:1961-1967
    Abstract: Advanced glycation endproducts (AGEs) accumulate on long-lived protein deposits including beta-amyloid plaques in Alzheimer's disease (AD). AGE-modified amyloid deposits contain oxidized and nitrated proteins as markers of a chronic neuroinflammatory condition and are surrounded by activated Microglial and astroglial cells. We show in this study that AGEs increase nitric oxide production by induction of the inducible nitric oxide synthase (iNOS) on the mRNA and protein level in the murine Microglial cell line N-11. Membrane permeable antioxidants including oestrogen derivatives (e.g. 17beta-oestradiol) thiol antioxidants (e.g. (R+)-alpha-lipoic acid) and Gingko biloba extract EGb 761, but not phosphodiesterase inhibitors such as propentophylline, prevent the up-regulation of AGE-induced iNOS expression and NO production. These results indicate that oxygen free radicals serve as second messengers in AGE-induced pro-inflammatory signal transduction pathways. As this pharmacological mechanism is not only relevant for Alzheimer's disease, but also for many chronic inflammatory conditions, such membrane-permeable antioxidants could be regarded not only as antioxidant, but also as potent therapeutic anti-inflammatory drugs

  205. Wyss-Coray T, Lin C, Yan F, Yu GQ, Rohde M, McConlogue L, Masliah E, Mucke L (2001) TGF-beta1 promotes Microglial amyloid-beta clearance and reduces plaque burden in transgenic mice. Nat.Med. 7:612-618
    Abstract: Abnormal accumulation of the amyloid-beta peptide (Abeta) in the brain appears crucial to pathogenesis in all forms of Alzheimer disease (AD), but the underlying mechanisms in the sporadic forms of AD remain unknown. Transforming growth factor beta1 (TGF-beta1), a key regulator of the brain's responses to injury and inflammation, has been implicated in Abeta deposition in vivo. Here we demonstrate that a modest increase in astroglial TGF-beta1 production in aged transgenic mice expressing the human beta-amyloid precursor protein (hAPP) results in a three-fold reduction in the number of parenchymal amyloid plaques, a 50% reduction in the overall Abeta load in the hippocampus and neocortex, and a decrease in the number of dystrophic neurites. In mice expressing hAPP and TGF-beta1, Abeta accumulated substantially in cerebral blood vessels, but not in parenchymal plaques. In human cases of AD, Abeta immunoreactivity associated with parenchymal plaques was inversely correlated with Abeta in blood vessels and cortical TGF-beta1 mRNA levels. The reduction of parenchymal plaques in hAPP/TGF-beta1 mice was associated with a strong activation of Microglia and an increase in inflammatory mediators. Recombinant TGF-beta1 stimulated Abeta clearance in Microglial cell cultures. These results demonstrate that TGF-beta1 is an important modifier of amyloid deposition in vivo and indicate that TGF-beta1 might promote Microglial processes that inhibit the accumulation of Abeta in the brain parenchyma

  206. Yamada M, Itoh Y, Sodeyama N, Suematsu N, Otomo E, Matsushita M, Mizusawa H (2001) Senile dementia of the neurofibrillary tangle type: a comparison with Alzheimer's disease. Dement.Geriatr.Cogn Disord. 12:117-126
    Abstract: A subset of senile dementia, 'senile dementia (SD) of the neurofibrillary tangle (NFT) type' (SD-NFT), is characterized by numerous NFTs in the hippocampal region and absence or scarcity of senile plaques throughout the brain. To elucidate the pathogenesis of SD-NFT in comparison with Alzheimer's disease (AD), we investigated the hippocampal lesions and analyzed the tau gene. The hippocampal regions from 5 patients with SD-NFT were neuropathologically evaluated in comparison with AD and nondemented control subjects. The tau gene was analyzed in 3 patients with SD-NFT. The densities of NFTs in the CA1/subiculum and entorhinal cortex of SD-NFT were significantly higher than those in AD. However, hippocampal atrophy, neuronal and synaptic loss, and astrocytic and Microglial proliferation in SD-NFT were significantly mild compared with AD. There was no significant difference between SD-NFT and AD in the immunoreactivities of NFTs with different anti-tau antibodies. No mutation was found in the tau gene from the SD-NFT patients. Our results indicate that the neurodegenerative process with NFT formation of the hippocampal region in SD-NFT would be different from that in AD

  207. Yasojima K, Tourtellotte WW, McGeer EG, McGeer PL (2001) Marked increase in cyclooxygenase-2 in ALS spinal cord: implications for therapy. Neurology 57:952-956
    Abstract: OBJECTIVE: To evaluate the hypothesis that cyclooxygenase-2 (COX-2) is linked to the pathology of ALS by determining whether COX-2 mRNA levels are upregulated in ALS spinal cord. METHODS: Spinal cord from 11 ALS cases and 27 controls consisting of 15 cases of Alzheimer disease (AD), six cases of Parkinson disease (PD), three cases of cerebrovascular disease, and three control cases were analyzed. Total RNA was extracted and reverse transcriptase-PCR analysis performed for the mRNA of COX-2, COX-1, the Microglial marker CD11b, and the housekeeping gene cyclophilin. RESULTS: In ALS compared with non-ALS spinal cord, COX-2 mRNA was upregulated 7.09-fold (p < 0.0001), COX-1 1.14-fold (p = 0.05), and CD11b 1.85-fold (p = 0.0012). COX-2 mRNA levels in AD, PD, cerebrovascular disease, and control cases were each significantly lower than in ALS and were not significantly different from each other. Western blots of the protein products were in general accord with the mRNA data, with COX-2 protein levels being upregulated 3.79-fold compared with non-ALS cases (p = 0.015). CONCLUSIONS: The strong upregulation of COX-2 mRNA in ALS is in accord with studies in the superoxide dismutase transgenic mouse model in which COX-2 upregulation occurs. Taken in conjunction with evidence of a neuroprotective effect of COX-2 inhibitors in certain animal models and in organotypic cultures, the data are supportive of a possible future role for COX-2 inhibitors in the treatment of ALS

  208. Akiyama H, Arai T, Kondo H, Tanno E, Haga C, Ikeda K (2000) Cell mediators of inflammation in the Alzheimer disease brain. Alzheimer Dis.Assoc.Disord. 14 Suppl 1:S47-S53
    Abstract: Lesions of Alzheimer disease are associated with low-grade but sustained inflammatory responses. Activated Microglia agglomerate in the center of senile plaques. Reactive astrocytes marginate the amyloid beta-protein (A beta) deposits and extend their processes toward the center of plaques. Both Microglia and astrocytes are known to secrete a wide variety of molecules involved in inflammation and are potential sources of proinflammatory elements in the brain. Dystrophic neurites occur in senile plaques with such glial reactions, suggesting the relevance of inflammatory responses to the neuronal degeneration in Alzheimer disease. Activated glial cells are, therefore, targets of anti-inflammatory therapy of Alzheimer disease. However, evidence also indicates that these cells eliminate A beta from the brain. A beta is produced continuously in both the normal and the AD brain. Under normal conditions, A beta is removed successfully before it accumulates as extracellular amyloid fibrils. Even in Alzheimer disease, a large portion of A beta may be cleared from the brain with a small portion being left and deposited as neurotoxic senile plaques. Both in vivo and in vitro studies showed the effective uptake of A beta by Microglia. Before clinical application, it must be determined whether the treatment that suppresses glial activation and inflammatory responses inhibits A beta removal by glial cells

  209. Aldskogius H (2000) [Microglia--new target cells for neurological therapy]. Lakartidningen 97:3358-3362
    Abstract: Disturbances in the normal homeostasis of the central nervous system induce a localized activation of Microglia. This activation serves to isolate pathological processes from surrounding, intact nervous tissue. Concomitantly, healthy or minimally damaged nerve cells nearby may be negatively influenced by potent molecules released by activated Microglia. This situation appears to exist e.g. in ischemia, multiple sclerosis and Alzheimer's disease. Pharmacologic regulation of Microglial activity is therefore a rational approach to treatment of many central nervous system disorders

  210. Arends YM, Duyckaerts C, Rozemuller JM, Eikelenboom P, Hauw JJ (2000) Microglia, amyloid and dementia in Alzheimer disease. A correlative study. Neurobiol.Aging 21:39-47
    Abstract: To elucidate the role of Microglia in Alzheimer's disease, a clinicopathological study was performed involving 26 cases, the mental status of which had been studied pre mortem by the Blessed test score (BTS). We measured the volume density of CD 68 immunoreactive (IR) Microglia, congophilic plaques and Abeta deposits, and the numerical density of neurofibrillary tangles (NFT) in a sample of Area 9 (middle frontal gyrus). Dementia was significantly correlated only with the volume density of Abeta deposits and the numerical density of NFT. The volume densities of Microglia and congophilic plaques were strongly correlated. With the intellectual status used as a time scale, IR Microglia and amyloid deposits appeared almost simultaneously at an early stage in the pathological cascade and decreased, whereas Abeta and NFT were still accumulating. The intellectual deficit seemed to be more significantly related to the latter two lesions than to the Microglia-amyloid complex, that was visible at an earlier stage (around BTS = 15)

  211. Arnold SE, Han LY, Clark CM, Grossman M, Trojanowski JQ (2000) Quantitative neurohistological features of frontotemporal degeneration. Neurobiol.Aging 21:913-919
    Abstract: Frontotemporal degeneration (FTD) is a neurodegenerative condition that has been principally associated with frontal lobe dementia. In this study, we compared neuropathological abnormalities in frontal, hippocampal, and calcarine cortices from patients assigned a diagnosis of FTD, normal elderly and Alzheimer's disease (AD). Densities of Nissl-stained neurons and lesions which were immunolabeled for tau, beta-amyloid (Abeta), alpha- and beta-synuclein, ubiquitin, glial fibrillary acidic protein (GFAP) and CD68 antigen were determined using computer-assisted, non-biased quantitative microscopy. We found that FTD frontal and hippocampal regions exhibited marked neuron loss, abundant ubiquitin-immunoreactive (ir) dystrophic neurites, GFAP-ir astrocytes, and CD68-ir Microglia, while calcarine cortex was spared. No alpha- or beta-synuclein-ir lesions were observed, and neither the density of tau-ir neurofibrillary tangles nor that of Abeta-ir plaques in FTD exceeded normal controls. In addition, there were no neuropathological differences between FTD subjects who presented clinically with a frontal lobe dementia versus an AD-like dementia. These findings indicate that FTD is a category of neurodegnerative dementias with varying clinical presentations that is characterized by the progressive degeneration of select populations of cortical neurons. The molecular neurodegenerative mechanisms that lead to FTD remain to be elucidated

  212. Bard F, Cannon C, Barbour R, Burke RL, Games D, Grajeda H, Guido T, Hu K, Huang J, Johnson-Wood K, Khan K, Kholodenko D, Lee M, Lieberburg I, Motter R, Nguyen M, Soriano F, Vasquez N, Weiss K, Welch B, Seubert P, Schenk D, Yednock T (2000) Peripherally administered antibodies against amyloid beta-peptide enter the central nervous system and reduce pathology in a mouse model of Alzheimer disease. Nat.Med. 6:916-919
    Abstract: One hallmark of Alzheimer disease is the accumulation of amyloid beta-peptide in the brain and its deposition as plaques. Mice transgenic for an amyloid beta precursor protein (APP) mini-gene driven by a platelet-derived (PD) growth factor promoter (PDAPP mice), which overexpress one of the disease-linked mutant forms of the human amyloid precursor protein, show many of the pathological features of Alzheimer disease, including extensive deposition of extracellular amyloid plaques, astrocytosis and neuritic dystrophy. Active immunization of PDAPP mice with human amyloid beta-peptide reduces plaque burden and its associated pathologies. Several hypotheses have been proposed regarding the mechanism of this response. Here we report that peripheral administration of antibodies against amyloid beta-peptide, was sufficient to reduce amyloid burden. Despite their relatively modest serum levels, the passively administered antibodies were able to enter the central nervous system, decorate plaques and induce clearance of preexisting amyloid. When examined in an ex vivo assay with sections of PDAPP or Alzheimer disease brain tissue, antibodies against amyloid beta-peptide triggered Microglial cells to clear plaques through Fc receptor-mediated phagocytosis and subsequent peptide degradation. These results indicate that antibodies can cross the blood-brain barrier to act directly in the central nervous system and should be considered as a therapeutic approach for the treatment of Alzheimer disease and other neurological disorders

  213. Barger SW, Chavis JA, Drew PD (2000) Dehydroepiandrosterone inhibits Microglial nitric oxide production in a stimulus-specific manner. J.Neurosci.Res. 62:503-509
    Abstract: Dehydroepiandrosterone (DHEA) is a steroid that circulates in abundance in the form of a sulfated reserve (DHEA-S). The levels of DHEA decline with age and further in age-related neuropathologies, including Alzheimer disease. Because of their reported anti-inflammatory effects, we tested the actions of these compounds on Microglia. At concentrations of 3(-9) to 1(-6) M, DHEA and DHEA-S inhibited the production of nitrite and morphological changes stimulated by lipopolysaccharide. DHEA and DHEA-S also inhibited LPS induction of iNOS protein, but neither inhibited LPS-induced iNOS mRNA or the activation of NF-kappaB. These data suggest that the hormone regulates nitrite production through a post-transcriptional mechanism. Interestingly, Microglial nitrite production in response to a secreted form of the beta-amyloid precursor protein (sAPP) was unaffected by DHEA. Another Alzheimer-related factor, amyloid beta-peptide, also stimulated Microglial nitrite production but in a manner dependent on the co-stimulus interferon-gamma. DHEA was found to inhibit only the interferon-gamma component of the Microglial response. These data add to a growing body of evidence for differences in the profiles of mononuclear phagocytes activated by distinct stimuli

  214. Bertram L, Blacker D, Mullin K, Keeney D, Jones J, Basu S, Yhu S, McInnis MG, Go RC, Vekrellis K, Selkoe DJ, Saunders AJ, Tanzi RE (2000) Evidence for genetic linkage of Alzheimer's disease to chromosome 10q. Science 290:2302-2303
    Abstract: Recent studies suggest that insulin-degrading enzyme (IDE) in neurons and Microglia degrades Abeta, the principal component of beta-amyloid and one of the neuropathological hallmarks of Alzheimer's disease (AD). We performed parametric and nonparametric linkage analyses of seven genetic markers on chromosome 10q, six of which map near the IDE gene, in 435 multiplex AD families. These analyses revealed significant evidence of linkage for adjacent markers (D10S1671, D10S583, D10S1710, and D10S566), which was most pronounced in late-onset families. Furthermore, we found evidence for allele-specific association between the putative disease locus and marker D10S583, which has recently been located within 195 kilobases of the IDE gene

  215. Blain H, Jouzeau JY, Blain A, Terlain B, Trechot P, Touchon J, Netter P, Jeandel C (2000) [Non-steroidal anti-inflammatory drugs with selectivity for cyclooxygenase-2 in Alzheimer's disease. Rationale and perspectives]. Presse Med. 29:267-273
    Abstract: POSSIBLE INFLAMMATORY MECHANISMS: Alzheimer's disease (AD) is a degenerative disease of the brain including possibly inflammatory mechanisms, as illustrated by the presence of activated Microglial cells in the periphery of senile plaques and neurofibrillary tangles and the subsequent release of proinflammatory mediators with neurotoxic potency. RATIONALE FOR NSAID USE: Although not firmly demonstrated, the rationale for the prescription of non steroidal anti-inflammatory drugs (NSAIDS) as neuroprotective agents in AD lies on epidemiological data having shown a reduced risk of developing AD in patients on long-term therapy with NSAIDs (non selective cyclo-oxygenase [COX] inhibitors). RATIONALE FOR THE USE OF SELECTIVE COX-2 INHIBITORS: The rationale for the prescription of selective COX-2 inhibitors as neuroprotective drugs in AD lies on: Epidemiological data having shown a reduced risk of developing AD in patients treated with anti-inflammatory doses of classical NSAIDs (inhibition of COX-1 and COX-2) but not with antithrombotic doses of aspirin (selective inhibition of COX-1), Cellular experiments, Demonstration of a better gastro-intestinal (GI) safety profile with selective COX-2 inhibitors than with classical NSAIDs in short-term studies, allowing a possible long-term use in AD. BEFORE PRESCRIBING: COX-2 may have an ambivalent functionality in the brain since the basal production of prostaglandins through COX-2 may participate in neuronal homeostasis whereas the expression of COX-2 is associated with brain development. Classical NSAIDs are ineffective in reducing the formation of senile plaque and neurofibrillary tangles in AD, which is consistent with an ability to reduce inflammation associated with activation of Microglia but illustrates their failure to suppress the degenerative process. Prophylactic use of selective COX-2 NSAIDs can be considered on the basis of their good GI safety after 6 months of marketing in United States but need to be confirmed for a longer time. CURRENT TRIALS: Clinical studies focusing on both the prevention and the slowing down of early AD are under way with two recently launched selective COX-2 inhibitors, celecoxib and rofecoxib

  216. Bornemann KD, Staufenbiel M (2000) Transgenic mouse models of Alzheimer's disease. Ann.N.Y.Acad.Sci. 908:260-266
    Abstract: Alzheimer's disease (AD) pathology is characterized by A beta peptide-containing plaques, neurofibrillary tangles consisting of hyperphosphorylated tau, extensive neuritic degeneration, and distinct neuron loss. We generated several transgenic mouse lines expressing the human amyloid precursor protein (APP751) containing the AD-linked KM670/671NL double mutation (Swedish mutation) under the control of a neuron-specific Thy-1 promoter fragment. In the best APP-expressing line (APP23), compact A beta deposits can be detected at 6 months of age. These plaques dramatically increase with age, are mostly Congo Red positive, and accumulate typical plaque-associated proteins such as heparansulfate proteoglycan and apolipoprotein E. Activated astrocytes and Microglia indicative of inflammatory processes reminiscent of AD accumulate around the deposits. Furthermore, plaques are surrounded by enlarged dystrophic neurites as visualized by neurofilament or Holmes-Luxol staining. Strong staining for acetylcholinesterase activity is found throughout the plaques and is accompanied by local distortion of the cholinergic fiber network. All congophilic plaques contain hyperphosphorylated tau reminiscent of early tau pathology. Modern stereologic methods demonstrate a significant loss of neurons in the hippocampal CA1 region, correlating with an increasing A beta plaque load. Interestingly, APP23 mice develop cerebral amyloid angiopathy in addition to amyloid plaques even though the APP transgene is only expressed in neurons. Crossbreeding of APP23 mice with transgenic mice carrying AD-linked presenilin mutations but not wild-type presenilin resulted in enhanced formation of pathology. In conclusion, our APP transgenic mice present many pathologic features, similar to those observed in AD and therefore offer excellent tools for studying the contribution of A beta to AD pathogenesis

  217. Brazil MI, Chung H, Maxfield FR (2000) Effects of incorporation of immunoglobulin G and complement component C1q on uptake and degradation of Alzheimer's disease amyloid fibrils by Microglia. J.Biol.Chem. 275:16941-16947
    Abstract: Microglia are macrophage-like immune system cells found in the brain. They are associated with Alzheimer's Disease plaques, which contain fibrillar beta-amyloid (fAbeta) and other components such as complement proteins. We have shown previously that murine Microglia bind and internalize fAbeta microaggregates via the type A scavenger receptor, but degradation of internalized fAbeta is significantly slower than normal degradation. In this study, we compared internalization by Microglia of fAbeta microaggregates to that of anti-Abeta-antibody-coated fAbeta (IgG-fAbeta) microaggregates and found that the uptake of the latter is increased by about 1.5-fold versus unmodified fAbeta. The endocytic trafficking of IgG-fAbeta is similar to that of fAbeta microaggregates, following an endosomal/lysosomal pathway. We also compared the internalization of fAbeta microaggregates to that of complement protein, C1q-coated fAbeta microaggregates, and found that the levels of uptake are also increased by about 1.5-fold. Rates of degradation of both types of modified fAbeta microaggregates are unchanged compared with unmodified fAbeta microaggregates. We demonstrated by blocking studies that internalization of IgG-fAbeta is mediated by Fc receptors. These data suggest that, in vivo, several different Microglial receptors may play a part in internalizing fAbeta, but the involvement of other receptors may not increase the degradation of fAbeta

  218. Calingasan NY, Gibson GE (2000) Vascular endothelium is a site of free radical production and inflammation in areas of neuronal loss in thiamine-deficient brain. Ann.N.Y.Acad.Sci. 903:353-356
    Abstract: Free radical production in vascular endothelial cells and inflammatory responses in perivascular Microglia accompany the selective neuronal death induced by TD. Lipid peroxidation and tyrosine nitration occur in neurons within susceptible areas. Thus, region- and cell-specific oxidative stress contributes to selective neurodegeneration during TD. These data are consistent with the hypothesis that in TD, vascular factors constitute a critical part of a cascade of events leading to increases in blood-brain barrier permeability to nonneuronal proteins and iron, leading to inflammation and oxidative stress. Inflammatory cells may release deleterious compounds or cytokines that exacerbate the oxidative damage to metabolically compromised neurons. Similar mechanisms may operate in the pathophysiology of neurodegenerative diseases in which vascular factors, inflammation and oxidative stress are implicated including AD

  219. Cole GM, Ard MD (2000) Influence of lipoproteins on Microglial degradation of Alzheimer's amyloid beta-protein. Microsc.Res.Tech. 50:316-324
    Abstract: Amyloid beta-protein (Abeta), the major component of plaques in Alzheimer's disease, is a small hydrophobic protein that is carried on apolipoprotein E (ApoE)- and ApoJ-containing lipoprotein particles in plasma and cerebrospinal fluid (CSF). Microglia, the scavenger cells of the CNS, take up and degrade Abeta via lipoprotein receptors including scavenger receptors A and B, and possibly via other receptors. Lipoproteins, ApoE, and ApoJ influence the uptake and degradation of Abeta in vitro and in vivo. Differences in ApoE-E4, -E3, and -E2 isoforms with respect to Abeta binding to lipoproteins and delivery to cells, including Microglia, may contribute to the increased risk of Alzheimer's disease for people with an APOE4 genotype and to risk reduction with APOE2

  220. Colton CA, Chernyshev ON, Gilbert DL, Vitek MP (2000) Microglial contribution to oxidative stress in Alzheimer's disease. Ann.N.Y.Acad.Sci. 899:292-307
    Abstract: Microglia are the CNS macrophage and are a primary cellular component of plaques in Alzheimer's disease (AD) that may contribute to the oxidative stress associated with chronic neurodegeneration. We now report that superoxide anion production in Microglia or macrophages from 3 different species is increased by long term exposure (24 hours) to A beta peptides. Since A beta competes for the uptake of opsonized latex beads and for the production of superoxide anion by opsonized zymosan, a likely site of action are membrane receptors associated with the uptake of opsonized particles or fibers. The neurotoxic fibrillar peptides A beta (1-42) and human amylin increase radical production whereas a non-toxic, non-fibrillar peptide, rat amylin, does not. We also report that the effect of A beta peptides on superoxide anion production is not associated with a concomitant increase in nitric oxide (NO) production in either human monocyte derived macrophages (MDM) or hamster Microglia from primary cultures. Since NO is known to protect membrane lipids and scavenge superoxide anion, the lack of A beta-mediated induction of NO production in human Microglia and macrophages may be as deleterious as the over-production of superoxide anion induced by chronic exposure to A beta peptides

  221. Combs CK, Johnson DE, Karlo JC, Cannady SB, Landreth GE (2000) Inflammatory mechanisms in Alzheimer's disease: inhibition of beta-amyloid-stimulated proinflammatory responses and neurotoxicity by PPARgamma agonists. J.Neurosci. 20:558-567
    Abstract: Alzheimer's disease (AD) is characterized by the extracellular deposition of beta-amyloid fibrils within the brain and the subsequent association and phenotypic activation of Microglial cells associated with the amyloid plaque. The activated Microglia mount a complex local proinflammatory response with the secretion of a diverse range of inflammatory products. Nonsteroidal anti-inflammatory drugs (NSAIDs) are efficacious in reducing the incidence and risk of AD and significantly delaying disease progression. A recently appreciated target of NSAIDs is the ligand-activated nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma). PPARgamma is a DNA-binding transcription factor whose transcriptional regulatory actions are activated after agonist binding. We report that NSAIDs, drugs of the thiazolidinedione class, and the natural ligand prostaglandin J2 act as agonists for PPARgamma and inhibit the beta-amyloid-stimulated secretion of proinflammatory products by Microglia and monocytes responsible for neurotoxicity and astrocyte activation. The activation of PPARgamma also arrested the differentiation of monocytes into activated macrophages. PPARgamma agonists were shown to inhibit the beta-amyloid-stimulated expression of the cytokine genes interleukin-6 and tumor necrosis factor alpha. Furthermore, PPARgamma agonists inhibited the expression of cyclooxygenase-2. These data provide direct evidence that PPARgamma plays a critical role in regulating the inflammatory responses of Microglia and monocytes to beta-amyloid. We argue that the efficacy of NSAIDs in the treatment of AD may be a consequence of their actions on PPARgamma rather than on their canonical targets the cyclooxygenases. Importantly, the efficacy of these agents in inhibiting a broad range of inflammatory responses suggests PPARgamma agonists may provide a novel therapeutic approach to AD

  222. De Groot CJ, Montagne L, Janssen I, Ravid R, van d, V, Veerhuis R (2000) Isolation and characterization of adult Microglial cells and oligodendrocytes derived from postmortem human brain tissue. Brain Res.Brain Res.Protoc. 5:85-94
    Abstract: The present study provides a detailed description of the simultaneous establishment and immunocytochemical characterization of highly enriched human adult Microglial cell cultures as well as of oligodendrocyte cultures. For this study, brain tissue specimens were collected at autopsy with relatively short postmortem times (3-9 h) from various regions of the CNS of Alzheimer's disease, Pick's disease and non-demented control cases. Although methods to isolate viable glial cells from human adult brain tissue have been described, these human brain specimens were often derived from surgical resections, i.e., in order to treat intractable epilepsy, brain tumors or cardiovascular diseases involving the brain. However, for the study of many neurological disorders, surgical material is not available. Furthermore, for obvious reasons, there is a limit to the number of central nervous system (CNS) regions from which (enough) tissue can be obtained at surgery. The adherent primary Microglial cells, isolated according to the here described procedures consisted of proliferating, phagocytotic cells that expressed various Microglia/macrophage-specific markers as judged by immunocytochemical analysis. Non-adherent cells isolated from the same brain tissue samples expressed oligodendrocyte-specific markers. The current described culture system may provide a valuable tool in studying human CNS biology and disease

  223. Deininger MH, Kremsner PG, Meyermann R, Schluesener HJ (2000) Differential cellular accumulation of transforming growth factor-beta1, -beta2, and -beta3 in brains of patients who died with cerebral malaria. J.Infect.Dis. 181:2111-2115
    Abstract: In cerebral malaria (CM), pathologic cytokine expression patterns are thought to contribute to disruption of the blood-brain barrier, inflammation, and astrocytic scar formation. Expression of transforming growth factor (TGF)-beta1, -beta2, and -beta3 was analyzed in the brains of 7 patients who died with CM and in 8 control patients. In the brains of patients with CM, there were significantly (P=.0003) more TGF-beta1-immunoreactive astrocytes adjacent to brain vessels with deposition of malarial pigment, significantly (P=.0081) more TGF-beta2-expressing macrophages/Microglial cells in glioses of ring hemorrhages and Durck's granulomas, and significantly (P=.0022) more TGF-beta3-expressing smooth-muscle cells and endothelial cells of brain vessels with sequestration. It is concluded that focal accumulation of TGF-beta1, -beta2, and -beta3 provides evidence for their involvement in the reorganization process of the brain parenchyma, immunologic dysfunction, and endothelial cell activation in patients with CM

  224. Diez M, Koistinaho J, Kahn K, Games D, Hokfelt T (2000) Neuropeptides in hippocampus and cortex in transgenic mice overexpressing V717F beta-amyloid precursor protein--initial observations. Neuroscience 100:259-286
    Abstract: Immunohistochemistry was used to analyse 18- and 26-month-old transgenic mice overexpressing the human beta-amyloid precursor protein under the platelet-derived growth factor-beta promoter with regard to presence and distribution of neuropeptides. In addition, antisera/antibodies to tyrosine hydroxylase, acetylcholinesterase, amyloid peptide, glial fibrillary acidic protein and Microglial marker OX42 were used. These mice have been reported to exhibit extensive amyloid plaques in the hippocampus and cortex [Masliah et al. (1996) J. Neurosci. 16, 5795-5811].The most pronounced changes were related to neuropeptides, whereas differences between wild-type and transgenic mice were less prominent with regard to tyrosine hydroxylase and acetylcholinesterase. The main findings were of two types; (i) involvement of peptide-containing neurites in amyloid beta-peptide positive plaques, and (ii) more generalized changes in peptide levels in specific layers, neuron populations and/or subregions in the hippocampal formation and ventral cortices. In contrast, the parietal and auditory cortices were comparatively less affected. The peptide immunoreactivities most strongly involved, both in plaques and in the generalized changes, were galanin, neuropeptide Y, cholecystokinin and enkephalin.This study shows that there is considerable variation both with regard to plaque load and peptide expression even among homozygotes of the same age. The most pronounced changes, predominantly increased peptide levels, were observed in two 26-month-old homozygous mice, for example, galanin-, enkephalin- and cholecystokinin-like immunoreactivities in stratum lacunosum moleculare, and galanin, neuropeptide Y, enkephalin and dynorphin in mossy fibers. Many peptides also showed elevated levels in the ventral cortices. However, decreases were also observed. Thus, galanin-like immunoreactivity could not any longer be detected in the diffusely distributed (presumably noradrenergic) fiber network in all hippocampal and cortical layers, and dynorphin-like immunoreactivity was decreased in stratum moleculare, cholecystokinin-like immunoreactivity in mossy fibers and substance P-like immunoreactivity in fibers around granule cells.The significance of generalized peptide changes is at present unclear. For example, the increase in the mainly inhibitory peptides galanin, neuropeptide Y, enkephalin and dynorphin and the decrease in the mainly excitatory peptide cholecystokinin in mossy fibers (and of substance P fibers around granule cells) indicate a shift in balance towards inhibition of the input to the CA3 pyramidal cell layer. Moreover, it may be speculated that the increase in levels of some of the peptides represents a reaction to nerve injury with the aim to counteract, in different ways, the consequences of injury, for example by exerting trophic actions. Further studies will be needed to establish to what extent these changes are typical for Alzheimer mouse models in general or are associated with the V717F mutation and/or the platelet-derived growth factor-beta promoter

  225. Eikelenboom P, Rozemuller AJ, Hoozemans JJ, Veerhuis R, Van Gool WA (2000) Neuroinflammation and Alzheimer disease: clinical and therapeutic implications. Alzheimer Dis.Assoc.Disord. 14 Suppl 1:S54-S61
    Abstract: In Alzheimer disease brains, the amyloid plaques are closely associated with a locally induced, nonimmune-mediated, chronic inflammatory response without any apparent influx of leukocytes from the blood. The present findings indicate that in cerebral A beta diseases (Alzheimer disease, Down syndrome, hereditary cerebral hemorrhage with amyloidosis-Dutch type), the clinical symptoms are determined to a great extent by the site of inflammatory response. It was found that the formation of the amyloid-Microglia complex seems to be a relatively early pathogenic event that precedes the process of severe destruction of the neuropil. The idea that inflammation is implicated in Alzheimer pathology has received support from the epidemiologic studies indicating that the use of anti-inflammatory drugs can prevent or retard the Alzheimer disease process. In this contribution, we review the relationship between inflammation and clinical manifestation and the opportunities for anti-inflammatory treatments in Alzheimer disease

  226. Emilien G, Beyreuther K, Masters CL, Maloteaux JM (2000) Prospects for pharmacological intervention in Alzheimer disease. Arch.Neurol. 57:454-459
    Abstract: Alzheimer disease (AD) involves neuronal degeneration with impaired cholinergic transmission in the cerebral cortex and hippocampus in areas of the brain particularly associated with memory and higher intellectual functioning. Other neurotransmitter deficits also occur, but the mechanisms underlying the widespread impairment of synaptic functions remain uncertain. Research on the molecular basis of AD has elucidated a pathogenic pathway from which a range of rational pharmacological interventions has emerged. Although at least 3 cholinesterase inhibitors (tacrine hydrochloride, donepezil, and rivastigmine tartrate) are now available and provide patients with modest relief, the most promising strategy involves approaches to retarding, halting, or preventing the formation or accumulation of beta-amyloid (Abeta) plaques. Estrogen is believed to have antioxidant or other anti-Abeta effects, as hormonal replacement therapy in women with menopause is associated with a reduced risk or delayed onset of AD. The association between nonsteroidal anti-inflammatory drugs and a reduced risk of AD has not yet been confirmed, but these agents may protect the brain from the reactive glial and Microglial responses associated with Abeta deposition. Also, recent studies suggested that antioxidants, such as vitamin E taken alone or in combination with selegiline hydrochloride, can delay the progression of AD. Despite these encouraging results, no current therapy has been shown to halt or reverse the underlying disease process. The proof of the principle that anti-Abeta drugs will work in the transgenic models of AD is eagerly awaited with the expectation that they will eventually prove successful in humans

  227. Emmerling MR, Watson MD, Raby CA, Spiegel K (2000) The role of complement in Alzheimer's disease pathology. Biochim.Biophys.Acta 1502:158-171
    Abstract: Complement proteins are integral components of amyloid plaques and cerebral vascular amyloid in Alzheimer brains. They can be found at the earliest stages of amyloid deposition and their activation coincides with the clinical expression of Alzheimer's dementia. This review will examine the origins of complement in the brain and the role of beta-amyloid peptide (Abeta) in complement activation in Alzheimer's disease, an event that might serve as a nidus of chronic inflammation. Pharmacology therapies that may serve to inhibit Abeta-mediated complement activation will also be discussed

  228. Engelhardt JI, Le WD, Siklos L, Obal I, Boda K, Appel SH (2000) Stereotaxic injection of IgG from patients with Alzheimer disease initiates injury of cholinergic neurons of the basal forebrain. Arch.Neurol. 57:681-686
    Abstract: CONTEXT: The participation of an immune/inflammatory process in the pathomechanism of sporadic Alzheimer disease (AD) has been suggested by evidence for activated Microglia and the potential therapeutic benefit of anti-inflammatory medication. OBJECTIVE: To define a possible role for IgG in the immune/inflammatory process of AD in humans, we assayed the ability of IgG samples from patients with AD to target the injury to cholinergic neurons in rat basal forebrain in vivo. DESIGN: IgG purified from the serum or plasma from patients with AD and patients with other neurological disease who were used as control (DC) patients was injected stereotaxically into the medial septum of adult rats. Four weeks later coronal sections of the whole medial septum-diagonal bands of Broca region were immunostained for choline acetyltransferase (ChAT) to identify cholinergic neuronal cells. SETTING: University medical centers. PATIENTS: Blood samples were collected from 8 patients with probable and definite AD and from 6 age-matched DC patients. MAIN OUTCOME MEASURE: Detection of changes in the number of ChAT immunopositive cell profiles in sections and statistical evaluation. RESULTS: Four weeks after the injections, IgG samples from patients with AD significantly reduced the number of ChAT-immunostained cell profiles in the whole medial septum-diagonal bands of Broca region compared with IgGs from DC patients. Neither DC IgGs nor saline solution significantly decreased the number of ChAT-immunopositive neuronal cell profiles. CONCLUSION: Data document that IgG from patients with AD can target a stereotaxically induced immune/inflammatory injury to cholinergic neurons in the rat basal forebrain in vivo

  229. Gilbert DL (2000) Fifty years of radical ideas. Ann.N.Y.Acad.Sci. 899:1-14
    Abstract: My role in the free radical theory of oxygen toxicity is discussed. Rebeca Gerschman and I published several papers on this subject. This sparked my interest in geochemistry and I developed the idea that oxygen was the best qualified biological potential energy source for the following reasons: great abundance, easily accessible, possession of a high thermodynamic potential, and its slow reaction rate. Ionization radiation can be viewed as a catalyst for reactive oxygen species since a killing dose imparts an infinitesimal small amount of energy. Next, Carol A. Colton and I showed that in the mammalian brain that stimulated Microglia produce the superoxide radical anion and its implications in Alzheimer's disease is discussed. More recently, I have become interested in the role of sulfhydryl groups in transcription factors

  230. Grimaldi LM, Casadei VM, Ferri C, Veglia F, Licastro F, Annoni G, Biunno I, De Bellis G, Sorbi S, Mariani C, Canal N, Griffin WS, Franceschi M (2000) Association of early-onset Alzheimer's disease with an interleukin-1alpha gene polymorphism. Ann.Neurol. 47:361-365
    Abstract: Overexpression of the pluripotent cytokine interleukin-1 (IL-1) by Microglial cells correlates with formation of neuritic beta-amyloid plaques in Alzheimer's disease (AD). We evaluated polymorphisms in the genes coding for the IL-1alpha, IL-1beta, and IL-1 receptor antagonist cytokines, and tested their association with the occurrence and age at onset of sporadic AD. We found a strong association between the IL-1A T/T genotype and AD onset before 65 years of age (odds ratio, 4.86), with carriers of this genotype showing an onset of disease 9 years earlier than IL-1A C/C carriers. A weaker association with the age at onset was also shown for the IL-1B and IL-1RN genes. These data suggest either a direct effect of the IL-1 gene family, mainly IL-1A, on the clinical onset of AD, or a linkage dysequilibrium with an unknown locus relevant to AD on chromosome 2

  231. Halliday G, Robinson SR, Shepherd C, Kril J (2000) Alzheimer's disease and inflammation: a review of cellular and therapeutic mechanisms. Clin.Exp.Pharmacol.Physiol 27:1-8
    Abstract: 1. Of the neurodegenerative diseases that cause dementia, Alzheimer's disease (AD) is the most common. Three major pathologies characterize the disease: senile plaques, neurofibrillary tangles and inflammation. We review the literature on events contributing to the inflammation and the treatments thought to target this pathology. 2. The senile plaques of AD consist primarily of complexes of the beta-amyloid protein. This protein is central to the pathogenesis of the disease. 3. Inflammatory Microglia are consistently associated with senile plaques in AD, although the classic inflammatory response (immunoglobulin and leucocyte infiltration) is absent. beta-Amyloid fragments appear to mediate such inflammatory mechanisms by activating the complement pathway in a similar fashion to immunoglobulin. 4. Epidemiological studies have identified a reduced risk of AD in patients with arthritis and in leprosy patients treated with anti-inflammatory drugs. Longitudinal studies have shown that the consumption of anti-inflammatory medications reduces the risk of AD only in younger patients (< 75 years). 5. There is a considerable body of in vitro evidence indicating that the inflammatory response of Microglial cells is reduced by non-steroidal anti-inflammatory drugs (NSAID). However, no published data are available concerning the effects of these medications on brain pathology in AD. 6. Cyclo-oxygenase 2 enzyme is constitutively expressed in neurons and is up-regulated in degenerative brain regions in AD. Non-steroidal anti-inflammatory drugs may reduce this expression. 7. Platelets are a source of beta-amyloid and increased platelet activation and increased circulating beta-amyloid have been identified in AD. Anti-platelet medication (including NSAID) would prevent such activation and its potentially harmful consequences. 8. Increased levels of luminal beta-amyloid permeabilizes the blood-brain barrier (BBB) and increases vasoconstriction of arterial vessels, paralleling the alterations observed with infection and inflammation. Cerebral amyloidosis is highly prevalent in AD, compromising the BBB and vasoactivity. Anti-inflammatory medications may alleviate these problems

  232. Heemels MT (2000) Alzheimer's disease. Plaque removers and shakers. Nature 406:465

  233. Hull M, Lieb K, Fiebich BL (2000) Anti-inflammatory drugs: a hope for Alzheimer's disease? Expert.Opin.Investig.Drugs 9:671-683
    Abstract: Human brain cells are capable of initiating and amplifying a brain specific inflammatory response involving the synthesis of cytokines, acute-phase proteins, complement proteins, prostaglandins and oxygen radicals. In Alzheimer's disease (AD), all signs of an inflammatory Microglial and astroglial activation are present inside and outside amyloid depositions and along axons of neurones with neurofibrillary tangles. Cell culture and animal models suggest a bidirectional relationship between inflammatory activation of glial cells and the deposition of amyloid. Although it remains unclear which of the different pathophysiological processes in AD may be the driving force in an individual case, the inflammatory activation may increase the speed of cognitive decline. Epidemiological studies point to a reduced risk of AD among users of anti-inflammatory drugs. Therefore, anti-inflammatory drugs have become the focus of several new treatment strategies. A clinical trial with the non-steroidal anti-inflammatory drug (NSAID) indomethacin showed promising results, while a clinical trial with steroids did not show a beneficial effect. Further trials with NSAIDs such as unselective cyclooxygenase (COX) and selective cyclooxygenase-2 (COX-2) inhibitors are on their way. COX inhibitors may not only act on Microglial and astroglial cells but also reduce neuronal prostaglandin production. New data suggest that prostaglandins enhance neurotoxicity or induce pro-inflammatory cytokine synthesis in astroglial cells. Amongst these promising new strategies to reduce Microglial or monocyte activation, interfering with intracellular pathways has been shown to be effective in various cell culture and animal models but clinical studies have not yet been performed

  234. Hull MH, Fiebich BL, Lieb K (2000) Strategies to delay the onset of Alzheimer's disease. EXS 89:211-225
    Abstract: Several processes are implicated in the neuropathology of Alzheimer's disease (AD), such as the deposition of amyloid, the formation of paired helical filaments and the proinflammatory activation of Microglial and astroglial cells. Proinflammatory activation of glial cells has been a focus of research for a mere ten years now. However, the availability of and broad experience with anti-inflammatory drugs has led to several ongoing clinical trials to verify the capacity of anti-inflammatory drugs to ameliorate the deterioration in AD. The enzymatic cleavage of the amyloid-precursor-protein or the hyperphosphorylation of tau as well as the subsequent aggregation of the resulting products are further targets for drugs intended to delay the neuropathological destruction observed in AD

  235. Jellinger KA, Stadelmann C (2000) Mechanisms of cell death in neurodegenerative disorders. J.Neural Transm.Suppl 59:95-114
    Abstract: OBJECTIVE: Progressive cell loss in specific neuronal populations is the prominent pathological hallmark of neurodegenerative diseases, but its molecular basis remains unresolved. Apoptotic cell death has been implicated as a general mechanism in Alzheimer disease (AD) and other neurodegenerative disorders. However, DNA fragmention in neurons is too frequent to account for the continuous loss in these slowly progressive diseases. MATERIAL AND METHODS: In 9 cases of morphologically confirmed AD (CERAD criteria, Braak stages 5 or 6), 5 cases of Parkinson disease (PD) and 3 cases each of Dementia with Lewy bodies (DLB), Progressive Supranuclear Palsy (PSP), and Multiple System Atrophy (MSA), and 7 age-matched controls, the TUNEL method was used to detect DNA fragmentation, and immunohistochemistry for an array of apoptosis-related proteins (ARP), protooncogenes, and activated caspase-3 were performed. RESULTS: In AD, a considerable number of hippocampal neurons showed DNA fragmentation with a 3 to 5.7 fold increase related to neurofibrillary tangles and amyloid deposits, but only exceptional neurons displayed apoptotic morphology (1 in 1100-5000) and cytoplasmic immunoreactivity for ARPs and activated caspase-3 (1 in 2600 to 5650 hippocampal neurons), whereas no neurons were labeled in age-matched controls. Caspase-3 immunoreactivity was seen in granules of granulovacuolar degeneration, only rarely colocalized with tau-immunoreactivity. In PD, DLB, and MSA, TUNEL positivity and expression of ARPs or activated caspase-3 was only seen in Microglia, rare astrocytes and in oligodendroglia with cytoplasmic inclusions in MSA, but not in nigral or other neurons with or without Lewy bodies. In PSP, only single neurons but oligodendrocytes, some with tau deposits, in brainstem tegmentum and pontine nuclei were TUNEL-positive and expressed both ARPs and activated caspase-3. CONCLUSIONS: These data provide evidence for extremely rare apoptotic neuronal death in AD compatible with the progression of neuronal degeneration in this chronic disease. In other neurodegenerative disorders, apoptosis mainly involves Microglia and oligodendroglia, while alternative mechanisms of neuronal death may occur. Susceptible cell populations in a proapoptotic environment show increased vulnerability towards metabolic and other pathogenic factors, with autophagy as a possible protective mechanism in early stages of programmed cell death. The intracellular cascade leading to cell death still awaits elucidation

  236. Jellinger KA, Stadelmann CH (2000) The enigma of cell death in neurodegenerative disorders. J.Neural Transm.Suppl21-36
    Abstract: Progressive cell loss in specific neuronal populations is the pathological hallmark of neurodegenerative diseases, but its mechanisms remain unresolved. Apoptotic cell death has been implicated as a major mechanism in Alzheimer disease (AD), Parkinson disease (PD) and other neurodegenerative disorders. However, DNA fragmentation in human brain as a sign of neuronal cell injury is too frequent to account for the continuous loss in these slowly progressive diseases. In a series of autopsy confirmed cases of AD, PD, related disorders, and age-matched controls, DNA fragmentation using the TUNEL method, an array of apoptosis-related proteins (ARP), proto-oncogenes, and activated caspase-3, the key enzyme of late-stage apoptosis, were examined. In AD, a considerable number of hippocampal neurons and glial cells showed DNA fragmentation with a 3- to 6-fold increase related to neurofibrillary tangles and amyloid deposits, but only 1 in 2.600 to 5.600 neurons displayed apoptotic morphology and cytoplasmic immunoreactivity for activated caspase-3, whereas no neurons were labeled in age-matched controls. caspase-3 immunoreactivity was seen in granules of cells with granulovacuolar degeneration, in around 25% co-localized with early cytoplasmic deposition of tau-protein. In progressive supranuclear palsy, only single neurons and several oligodendrocytes in brainstem, some with tau-deposits, were TUNEL-positive and expressed both ARPs and activated caspase-3. In PD, dementia with Lewy bodies, multisystem atrophy (MSA), and corticobasal degeneration, TUNEL-positivity and expression of ARPs or activated caspase-3 were only seen in Microglia and oligodendrocytes with cytoplasmic inclusions, but not in neurons. These data provide evidence for extremely rare apoptotic neuronal death in AD and PSP compatible with the progression of neuronal degeneration in these chronic diseases. Apoptosis mainly involves reactive Microglia and oligodendroglia, the latter often involved by deposits of insoluble fibrillary proteins, while alternative mechanisms of neuronal death may occur. Susceptible cell populations in a proapoptotic environment show increased vulnerability towards metabolic or other noxious factors, with autophagy as a possible protective mechanism in early stages of programmed cell death. The intracellular cascade leading to cell death still awaits elucidation

  237. Kimura T, Yamamoto H, Takamatsu J, Yuzuriha T, Miyamoto E, Miyakawa T (2000) Phosphorylation of MARCKS in Alzheimer disease brains. Neuroreport 11:869-873
    Abstract: Activation of the amyloid beta-protein precursor, secretary pathway through alpha-secretase has been reported to increase the secretion of neuroprotective amyloid precursor protein and preclude the formation of amyloid beta-protein. Activation of protein kinase C has been shown to accelerate this secretory pathway. These results prompted us to focus on a potential links between protein kinase C and the amyloid beta-protein-related pathology of Alzheimer disease (AD). Although protein kinase C is reported to occur in senile plaques, its catalytic activity has not been investigated. As the phosphorylation of myristoylated alanine-rich C kinase substrate (MARCKS) has been used as a marker for activation of protein kinase C in vivo, we examined its phosphorylation in brain tissues obtained from seven AD patients and five non-demented subjects using an antibody that specifically recognized MARCKS phosphorylated by protein kinase C. Phosphorylation of MARCKS in cortical neurons in AD brains was weaker than that in control brains. Interestingly, however, phosphorylation of MARCKS was detected in Microglia and dystrophic neurites within neuritic plaques, a mature form of amyloid beta-protein deposits. These results suggest that protein kinase C alteration is associated with AD pathology and that protein kinase C is activated in Microglia and dystrophic neurites by amyloid beta-protein in AD brains

  238. Lee CK, Weindruch R, Prolla TA (2000) Gene-expression profile of the ageing brain in mice. Nat.Genet. 25:294-297
    Abstract: Ageing of the brain leads to impairments in cognitive and motor skills, and is the major risk factor for several common neurological disorders such as Alzheimer disease (AD) and Parkinson disease (PD). Recent studies suggest that normal brain ageing is associated with subtle morphological and functional alterations in specific neuronal circuits, as opposed to large-scale neuronal loss. In fact, ageing of the central nervous system in diverse mammalian species shares many features, such as atrophy of pyramidal neurons, synaptic atrophy, decrease of striatal dopamine receptors, accumulation of fluorescent pigments, cytoskeletal abnormalities, and reactive astrocytes and Microglia. To provide the first global analysis of brain ageing at the molecular level, we used oligonucleotide arrays representing 6,347 genes to determine the gene-expression profile of the ageing neocortex and cerebellum in mice. Ageing resulted in a gene-expression profile indicative of an inflammatory response, oxidative stress and reduced neurotrophic support in both brain regions. At the transcriptional level, brain ageing in mice displays parallels with human neurodegenerative disorders. Caloric restriction, which retards the ageing process in mammals, selectively attenuated the age-associated induction of genes encoding inflammatory and stress responses

  239. Li Y, Liu L, Kang J, Sheng JG, Barger SW, Mrak RE, Griffin WS (2000) Neuronal-glial interactions mediated by interleukin-1 enhance neuronal acetylcholinesterase activity and mRNA expression. J.Neurosci. 20:149-155
    Abstract: Cholinergic dysfunction in Alzheimer's disease has been attributed to stress-induced increases in acetylcholinesterase (AChE) activity. Interleukin-1 (IL-1) is overexpressed in Alzheimer's disease, and stress-related changes in long-term potentiation, an ACh-related cerebral function, are triggered by interleukin-1. Microglial cultures (N9) synthesized and released IL-1 in response to conditioned media obtained from glutamate-treated primary neuron cultures or PC12 cells. This conditioned media contained elevated levels of secreted beta-amyloid precursor protein (sAPP). Naive PC12 cells cocultured with stimulated N9 cultures showed increased AChE activity and mRNA expression. These effects on AChE expression and activity could be blocked by either preincubating the glutamate-treated PC12 supernatants with anti-sAPP antibodies or preincubating naive PC12 cells with IL-1 receptor antagonist. These findings were confirmed in vivo; IL-1-containing pellets implanted into rat cortex also increased AChE mRNA levels. Neuronal stress in Alzheimer's disease may induce increases in AChE expression and activity through a molecular cascade that is mediated by sAPP-induced Microglial activation and consequent overexpression of IL-1

  240. Liberski PP, Ironside J, McCardle L, Sherring A (2000) Ultrastructural analysis of the florid plaque in variant Creutzfeldt-Jakob disease. Folia Neuropathol. 38:167-170
    Abstract: We report here the first description of florid plaques--the hallmark of variant Creutzfeldt-Jakob disease (vCJD). These plaques are composed of broad bundles of amyloid, are highly neuritic and exhibited astrocytes and Microglial cells. Collectively, they are more similar to neuritic plaques of Alzheimer's disease than to kuru plaques of kuru--Creutzfeldt-Jakob disease--Gerstmann-Straussler-Sheinker disease

  241. Lim GP, Yang F, Chu T, Chen P, Beech W, Teter B, Tran T, Ubeda O, Ashe KH, Frautschy SA, Cole GM (2000) Ibuprofen suppresses plaque pathology and inflammation in a mouse model for Alzheimer's disease. J.Neurosci. 20:5709-5714
    Abstract: The brain in Alzheimer's disease (AD) shows a chronic inflammatory response characterized by activated glial cells and increased expression of cytokines and complement factors surrounding amyloid deposits. Several epidemiological studies have demonstrated a reduced risk for AD in patients using nonsteroidal anti-inflammatory drugs (NSAIDs), prompting further inquiries about how NSAIDs might influence the development of AD pathology and inflammation in the CNS. We tested the impact of chronic orally administered ibuprofen, the most commonly used NSAID, in a transgenic model of AD displaying widespread Microglial activation, age-related amyloid deposits, and dystrophic neurites. These mice were created by overexpressing a variant of the amyloid precursor protein found in familial AD. Transgene-positive (Tg+) and negative (Tg-) mice began receiving chow containing 375 ppm ibuprofen at 10 months of age, when amyloid plaques first appear, and were fed continuously for 6 months. This treatment produced significant reductions in final interleukin-1beta and glial fibrillary acidic protein levels, as well as a significant diminution in the ultimate number and total area of beta-amyloid deposits. Reductions in amyloid deposition were supported by ELISA measurements showing significantly decreased SDS-insoluble Abeta. Ibuprofen also decreased the numbers of ubiquitin-labeled dystrophic neurites and the percentage area per plaque of anti-phosphotyrosine-labeled Microglia. Thus, the anti-inflammatory drug ibuprofen, which has been associated with reduced AD risk in human epidemiological studies, can significantly delay some forms of AD pathology, including amyloid deposition, when administered early in the disease course of a transgenic mouse model of AD

  242. Lorton D, Schaller J, Lala A, De Nardin E (2000) Chemotactic-like receptors and Abeta peptide induced responses in Alzheimer's disease. Neurobiol.Aging 21:463-473
    Abstract: Evidence suggests that beta-amyloid (Abeta) has chemokine-like properties and may act through formyl chemotactic receptors (FPR) to induce pathophysiologically important functional changes in Alzheimer's disease (AD) Microglia. We have shown that Abeta 1-42, fibrillar Abeta 1-40, and Abeta 25-35 potentiate the release of interleukin-1beta (IL-1beta) from LPS activated human THP-1 monocytes [26] and LPS primed rat Microglia. Moreover, Abeta-stimulated IL-1beta secretion seems to be receptor mediated because it is calcium dependent and requires activation of specific G-proteins [27]. Thus, we have evaluated the ability of Abeta 1-42 to mimic formyl chemotactic peptides in stimulating IL-1beta release from THP-1 monocytes. Several of the formyl chemotactic peptides and Abeta 1-42 significantly enhanced IL-1beta production in THP-1 monocytes. In contrast, a formyl chemotactic receptor antagonist inhibited Abeta 1-42-induced IL-1beta release from both human THP-1 monocytes and primary rat Microglia. Further, primary rat Microglia grown in culture expressed FPR as demonstrated by immunocytochemistry. Given the multiple pathophysiologic roles IL-1beta may play in AD, agents that block Abeta interactions with formyl chemotactic receptors on Microglia might be important antiinflammatory therapeutic targets

  243. Lukiw WJ, Bazan NG (2000) Neuroinflammatory signaling upregulation in Alzheimer's disease. Neurochem.Res. 25:1173-1184
    Abstract: Alzheimer's disease (AD) is a progressive, neurodestructive process of the human neocortex, characterized by the deterioration of memory and higher cognitive function. A progressive and irreversible brain disorder, AD is characterized by three major pathogenic episodes involving (a) an aberrant processing and deposition of beta-amyloid precursor protein (betaAPP) to form neurotoxic beta-amyloid (betaA) peptides and an aggregated insoluble polymer of betaA that forms the senile plaque, (b) the establishment of intraneuronal neuritic tau pathology yielding widespread deposits of agyrophilic neurofibrillary tangles (NFT) and (c) the initiation and proliferation of a brain-specific inflammatory response. These three seemingly disperse attributes of AD etiopathogenesis are linked by the fact that proinflammatory Microglia, reactive astrocytes and their associated cytokines and chemokines are associated with the biology of the microtubule associated protein tau, betaA speciation and aggregation. Missense mutations in the presenilin genes PS1 and PS2, implicated in early onset familial AD, cause abnormal betaAPP processing with resultant overproduction of betaA42 and related neurotoxic peptides. Specific betaA fragments such as betaA42 can further potentiate proinflammatory mechanisms. Expression of the inducible oxidoreductase cyclooxygenase-2 and cytosolic phospholipase A2 (cPLA2) are strongly activated during cerebral ischemia and trauma, epilepsy and AD, indicating the induction of proinflammatory gene pathways as a response to brain injury. Neurotoxic metals such as aluminum and zinc, both implicated in AD etiopathogenesis, and arachidonic acid, a major metabolite of brain cPLA2 activity, each polymerize hyperphosphorylated tau to form NFT-like bundles. Further, epidemiological and longitudinal studies have identified a reduced risk for AD in patients (<70 yrs) previously treated with non-steroidal anti-inflammatory drugs for non-CNS afflictions that include arthritis. This review will focus on the interrelationships between the mechanisms of PS1, PS2 and betaAPP gene expression, tau and betaA deposition and the induction, regulation and proliferation in AD of the neuroinflammatory response. Novel therapeutic interventions in AD are discussed

  244. Mackenzie IR (2000) Anti-inflammatory drugs and Alzheimer-type pathology in aging. Neurology 54:732-734
    Abstract: Anti-inflammatory drugs have been suggested as a treatment for AD. The authors examined the AD-type pathology in postmortem brain tissue from elderly nondemented individuals who were chronically exposed to anti-inflammatory drugs. The results suggest that 1) these drugs do not affect the formation of either senile plaques or neurofibrillary tangles and 2) nonsteroidal anti-inflammatory drugs may be more effective than steroids in treating AD because of their ability to suppress the Microglial activation associated with senile plaques

  245. Mackenzie IR (2000) Activated Microglia in dementia with Lewy bodies. Neurology 55:132-134
    Abstract: To investigate the role of cerebral inflammation in dementia with Lewy bodies (DLB), activated Microglial cells were quantified in postmortem brain tissue. Patients with pure DLB (LB but no AD pathology) had significantly greater numbers of cells than nondemented control subjects, but fewer than patients with either pure AD or DLB combined with AD. There was a positive correlation between the numbers of activated Microglia and LB in different brain regions. This study demonstrates the presence of significant inflammation in DLB, even in the absence of AD pathology

  246. Marzolo MP, von Bernhardi R, Bu G, Inestrosa NC (2000) Expression of alpha(2)-macroglobulin receptor/low density lipoprotein receptor-related protein (LRP) in rat Microglial cells. J.Neurosci.Res. 60:401-411
    Abstract: Low density lipoprotein receptor-related protein (LRP) participates in the uptake and degradation of several ligands implicated in neuronal pathophysiology including apolipoprotein E (apoE), activated alpha(2) -macroglobulin (alpha(2)M*) and beta-amyloid precursor protein (APP). The receptor is expressed in a variety of tissues. In the brain LRP is present in pyramidal-type neurons in cortical and hippocampal regions and in astrocytes that are activated as a result of injury or neoplasmic transformation. As LRP is expressed in the monocyte/macrophage cell system, we were interested in examining whether LRP is expressed in Microglia. We isolated glial cells from the brain of neonatal rats and LRP was immunodetected both in Microglial cells and in astrocytes expressing glial fibrillar acidic protein (GFAP). Microglial cells were able to bind and internalize LRP-specific ligand, alpha(2)M*. The internalization was inhibitable by RAP, with a Kd of 1.7 nM. The expression of LRP was up-regulated by dexamethasone, and down-regulated by lipopolysaccharide (LPS), gamma interferon (IFN-gamma) or a combination of both. LRP was less sensitive to dexamethasone in activated astrocytes than in Microglia. We provided the first analysis of LRP expression and regulation in Microglia. Our results open the possibility that Microglial cells could be related to the participation of LRP and its ligands in different pathophysiological states in brain

  247. Masliah E, Rockenstein E (2000) Genetically altered transgenic models of Alzheimer's disease. J.Neural Transm.Suppl 59:175-183
    Abstract: Abnormal processing and aggregation of synaptic proteins might play an important role in the pathogenesis of neurodegenerative disorders. Among them, amyloid precursor protein (APP) has been clearly associated with Alzheimer's disease (AD) and various transgenic (tg) animal models have been developed where mutant APP is overexpressed under the regulatory control of neuronal promoters. These studies have shown that AD-like pathology (namely plaques and synapse damage) begins to develop at 6-8 months of age in mice expressing human APP under Thy1, platelet-derived growth factor (B-chain) or protease-resistant prion protein promoters, provided that levels of APP are higher than 5-7 fold of endogenous levels. None of these models have shown the presence of tangles; however, tau-immunoreactive neurites in plaques and astroglial/Microglial activation are observed after 12 months of age. Neuronal loss and alterations of synaptic function and connectivity are found in the CA1 region in the PDAPP tg mice lacking the Swiss Webster background. Co-expression of other genes associated with AD modify this phenotype, for example, mutant presenilin 1 accelerates the onset of plaque formation, transforming growth factor beta enhances vascular amyloidosis, and apolipoprotein E decreases amyloid deposition. In conclusion, tg mice which are capable of mimicking some aspects of AD (provided that high enough levels of expression are achieved) can potentially be used to test novel drugs for the treatment of neurodegenerative disorders

  248. Masumura M, Hata R, Nishimura I, Uetsuki T, Sawada T, Yoshikawa K (2000) Caspase-3 activation and inflammatory responses in rat hippocampus inoculated with a recombinant adenovirus expressing the Alzheimer amyloid precursor protein. Brain Res.Mol.Brain Res. 80:219-227
    Abstract: To elucidate the mechanism of neuronal death in Alzheimer's disease, we investigated the effects of overexpression of wild-type Alzheimer amyloid precursor protein (APP) on neuronal cells and glial cells in vivo. When an APP695-expressing adenovirus was injected into the dorsal hippocampal region, a number of neurons in remote areas were positively stained with anti-APP monoclonal antibody, and underwent severe degeneration from 3 to 7 days after viral inoculation. Most degenerating neurons were immunopositive with both APP and activated caspase-3, but some neurons that expressed activated caspase-3 were not expressing APP from 7 to 14 days after virus injection. In the neighborhood of the degenerating neurons, activated Microglia/macrophages, which were identified by the phenotypic marker C3bi receptor (CD11b/c; OX-42), were observed, and some of them appeared to phagocytose the caspase-3-immunopositive degenerating neurons. In addition to Microglia/macrophages, infiltrating leukocytes expressing CD45 or CD4 were also detected. These results suggest that the increased accumulation of APP induced not only caspase-3-mediated death machinery, but also inflammatory responses including Microglial activation. These inflammatory responses might cause further neurodegeneration through the alternative pathway that might activate the caspase-3-mediated death machinery without APP expression

  249. Matsumoto A, Itoh K, Matsumoto R (2000) A novel carboxypeptidase B that processes native beta-amyloid precursor protein is present in human hippocampus. Eur.J.Neurosci. 12:227-238
    Abstract: The processing of beta-amyloid precursor protein (APP) and generation of beta-amyloid (Abeta) are associated with the pathophysiology of Alzheimer's disease (AD). As the proteases responsible for the process in the human brain have yet to be clarified, we have searched for activities capable of cleaving native brain APP in the human hippocampus. A 40-kDa protein with proteolytic activity that degrades native brain APP in vitro was purified and characterized; molecular analysis identified it as a novel protease belonging to the carboxypeptidase B (CPB) family. PC12 cells overexpressing the cDNA encoding this protease generate a major 12-kDa beta-amyloid-bearing peptide in cytosol, a peptide which has also been detected in a cell-free system using purified brain APP as substrate. Although the protease is homologous to plasma CPB synthesized in liver, it has specific domains such as C-terminal 14 amino acid residues. Western analysis, cDNA-cloning process and Northern analysis suggested a brain-specific expression of this protease. An immunohistochemical study showed that the protease is expressed in various neuronal perikarya, including those of pyramidal neurons of the hippocampus and ependymal-choroid plexus cells, and in a portion of the Microglia of normal brains. In brains of patients with sporadic AD, there is decreased neuronal expression of the protease, and clusters of Microglia with protease immunoreactivity associated with its extracellular deposition are detected. These findings suggest that brain CPB has a physiological function in APP processing and may have significance in AD pathophysiology

  250. McGeer PL, McGeer EG, Yasojima K (2000) Alzheimer disease and neuroinflammation. J.Neural Transm.Suppl 59:53-57
    Abstract: It is now generally accepted that the lesions of Alzheimer disease (AD) are associated with a host of inflammatory molecules, including complement proteins, as well as with many activated Microglia. Most inflammatory components are synthesized by brain cells. In order to estimate the intensity of the inflammatory reaction, we have measured the levels of the mRNAs for complement proteins, two complement regulators (CD59 and C1 inhibitors), an acute phase reactant (C-reactive protein, CRP) and two Microglial markers, (HLA-DR and CD11b), in normal and AD brain. The mRNAs for inflammatory mediators are markedly upregulated in AD tissue while those of the complement inhibitors are almost unchanged. The upregulations for CRP and CD11b in AD hippocampus are comparable to those in osteoarthritic joints. This lends further support to the hypothesis that chronic inflammation may be causing neuronal death in AD

  251. McGeer PL, McGeer EG (2000) Autotoxicity and Alzheimer disease. Arch.Neurol. 57:789-790
    Abstract: I mmunological responses are considered to be either humoral, resulting from cloning of B lymphocytes, or cell mediated, resulting from cloning of T lymphocytes. Autoimmune diseases occur when the cloned products attack host tissue. Inflammation is considered a nonspecific response to injury, characterized by exudation of serum into damaged tissue, and identified by the cardinal signs of rubor, calor, dolor, and tumor. However, these classic mechanisms do not fit pathological observations of Alzheimer disease (AD)-affected brain tissue. Although many of the components prominently associated with peripheral immunological and inflammatory states are present in AD lesions, there are no identifiable B lymphocytes or antibodies, and T cells are sparse. Furthermore, the blood-brain barrier is intact, excluding exudation of exogenous serum proteins. Although "neuroinflammation" is the term commonly used to describe the pathological changes, it fails to define adequately the process that is taking place. The reaction is neither a nonspecific response to injury, as classically implied for inflammatory reactions, nor an autoimmune reaction, despite the directed attack against plaques and extracellular tangles. It is most appropriately defined as an innate immunoreaction. The fact that such a reaction can be mounted by brain, an organ frequently described as being immunologically privileged, suggests that a reevaluation is required of the dimensions of the innate immune system, including how it operates at the tissue level. The innate immune system is primitive, while the adaptive immune system, which is directed by peripheral immune organs, is an invention of vertebrates. Even in vertebrates, however, the innate immune system is the first line of defense. Much more needs to be learned about the operation of the innate immune system in health and disease. Arch Neurol. 2000

  252. Mehlhorn G, Hollborn M, Schliebs R (2000) Induction of cytokines in glial cells surrounding cortical beta-amyloid plaques in transgenic Tg2576 mice with Alzheimer pathology. Int.J.Dev.Neurosci. 18:423-431
    Abstract: beta-Amyloid plaque deposition observed in brains from Alzheimer patients, might function as immune stimulus for glial/macrophages activation, which is supported by observations of activated Microglia expressing interleukin (IL)-1beta and elevated IL-6 immunoreactivity in close proximity to amyloid plaques. To elucidate the mechanisms involved in beta-amyloid-mediated inflammation, transgenic mice (Tg2576) expressing high levels of the Swedish double mutation of human amyloid precursor protein and progressively developing typical beta-amyloid plaques in cortical brain regions including gliosis and astrocytosis, were examined for the expression pattern of a number of cytokines.Using ribonuclease protection assay, interleukin (IL)-1alpha,-beta, IL-1 receptor antagonist, IL-6, IL-10, IL-12, IL-18, interferon-gamma, and macrophage migration inhibitory factor (MIF) mRNA were not induced in a number of cortical areas of Tg2576 mice regardless of the postnatal ages studied ranging between 2 and 13 months. Using immunocytochemistry for IL-1alpha,beta, IL-6, tumor necrosis factor (TNF)-alpha, and macrophage chemotactic protein (MCP)-1, only IL-1beta was found to be induced in reactive astrocytes surrounding beta-amyloid deposits detected in 14-month-old Tg2576 mice. Using non-radioactive in situ hybridization glial fibrillary acidic protein (GFAP) mRNA was detected to be expressed by reactive astrocytes in close proximity to beta-amyloid plaques. The local immune response detected around cortical beta-amyloid deposits in transgenic Tg2576 mouse brain is seemingly different to that observed in brains from Alzheimer patients but may represent an initial event of chronic neuroinflammation at later stages of the disease

  253. Morgan TE, Rozovsky I, Sarkar DK, Young-Chan CS, Nichols NR, Laping NJ, Finch CE (2000) Transforming growth factor-beta1 induces transforming growth factor-beta1 and transforming growth factor-beta receptor messenger RNAs and reduces complement C1qB messenger RNA in rat brain Microglia. Neuroscience 101:313-321
    Abstract: Transforming growth factor-beta1 is a multifunctional peptide with increased expression during Alzheimer's disease and other neurodegenerative conditions which involve inflammatory mechanisms. We examined the autoregulation of transforming growth factor-beta1 and transforming growth factor-beta receptors and the effects of transforming growth factor-beta1 on complement C1q in brains of adult Fischer 344 male rats and in primary glial cultures. Perforant path transection by entorhinal cortex lesioning was used as a model for the hippocampal deafferentation of Alzheimer's disease. In the hippocampus ipsilateral to the lesion, transforming growth factor-beta1 peptide was increased >100-fold; the messenger RNAs encoding transforming growth factor-beta1, transforming growth factor-beta type I and type II receptors were also increased, but to a smaller degree. In this acute lesion paradigm, Microglia are the main cell type containing transforming growth factor-beta1, transforming growth factor-beta type I and II receptor messenger RNAs, shown by immunocytochemistry in combination with in situ hybridization. Autoregulation of the transforming growth factor-beta1 system was examined by intraventricular infusion of transforming growth factor-beta1 peptide, which increased hippocampal transforming growth factor-beta1 messenger RNA levels in a dose-dependent fashion. Similarly, transforming growth factor-beta1 increased levels of transforming growth factor-beta1 messenger RNA and transforming growth factor-beta type II receptor messenger RNA (IC(50), 5pM) and increased release of transforming growth factor-beta1 peptide from primary Microglia cultures. Interactions of transforming growth factor-beta1 with complement system gene expression are also indicated, because transforming growth factor-beta1 decreased C1qB messenger RNA in the cortex and hippocampus, after intraventricular infusion, and in cultured glia. These indications of autocrine regulation of transforming growth factor-beta1 in the rodent brain support a major role of Microglia in neural activities of transforming growth factor-beta1 and give a new link between transforming growth factor-beta1 and the complement system. The auto-induction of the transforming growth factor-beta1 system has implications for transgenic mice that overexpress transforming growth factor-beta1 in brain cells and for its potential role in amyloidogenesis

  254. Murphy GM, Jr., Zhao F, Yang L, Cordell B (2000) Expression of macrophage colony-stimulating factor receptor is increased in the AbetaPP(V717F) transgenic mouse model of Alzheimer's disease. Am.J.Pathol. 157:895-904
    Abstract: Inflammation is an important neuropathological change in Alzheimer's disease (AD). However, the pathophysiological factors that initiate and maintain the inflammatory response in AD are unknown. We examined AbetaPP(V717F) transgenic mice, which show numerous brain amyloid-beta (Abeta) deposits, for expression of the macrophage colony-stimulating factor (M-CSF) and its receptor (M-CSFR). M-CSF is increased in the brain in AD and dramatically augments the effects of Abeta on cultured Microglia. AbetaPP(V717F) animals 12 months of age showed large numbers of Microglia strongly labeled with an M-CSFR antibody near Abeta deposits. M-CSFR mRNA and protein levels were also increased in brain homogenates from AbetaPP(V717F) animals. Dystrophic neurites and astroglia showed no M-CSFR labeling in the transgenic animals. A M-CSF antibody decorated neuritic structures near hippocampal Abeta deposits in transgenic animals. M-CSF mRNA was also increased in AbetaPP(V717F) animals in comparison with wild-type controls. Simultaneous overexpression of M-CSFR and its ligand in AbetaPP(V717F) animals could result in augmentation of Abeta-induced activation of Microglia. Because chronic activation of Microglia is thought to result in neuronal injury, the M-CSF system may be a potential target for therapeutic intervention in AD

  255. O'Barr S, Cooper NR (2000) The C5a complement activation peptide increases IL-1beta and IL-6 release from amyloid-beta primed human monocytes: implications for Alzheimer's disease. J.Neuroimmunol. 109:87-94
    Abstract: Alzheimer's disease (AD) brains contain large numbers of amyloid-beta peptide (Abeta) deposits associated with activated Microglia, astrocytes and dystrophic neurites. Activated complement components and pro-inflammatory cytokines are also present, indicative of focal inflammation. However, neither Abeta, nor the chemokine-like mediator, C5a, which is generated by Abeta-mediated complement activation, significantly activates Microglia, as assessed by pro-inflammatory cytokine release. We evaluated the possibility that both together would co-stimulate such release using the THP-1 human monocytic cell line as a Microglial surrogate, and found this to be the case. These studies support the hypothesis that Abeta and C5a induce a chronic Microglia-mediated focal inflammatory response in AD

  256. Ogawa K, Yamada T, Tsujioka Y, Taguchi J, Takahashi M, Tsuboi Y, Fujino Y, Nakajima M, Yamamoto T, Akatsu H, Mitsui S, Yamaguchi N (2000) Localization of a novel type trypsin-like serine protease, neurosin, in brain tissues of Alzheimer's disease and Parkinson's disease. Psychiatry Clin.Neurosci. 54:419-426
    Abstract: Neurosin, a novel type of trypsin-like serine protease, has been shown to be preferentially expressed in human brain by northern blotting. We examined neurosin immunolabeling in the brains of neurologically normal persons and patients with Alzheimer's disease (AD) and with Parkinson's disease. We also identified the expression of the mRNA for neurosin by in situ hybridization histochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The neurosin antibody stained all of the nuclei of various cell types. In neurons, there was also staining of neuronal cytoplasm, nucleoli and their processes. In AD, staining of neurons with processes was rare in the damaged areas. Some senile plaques, extracellular tangles and Lewy bodies were also positive for neurosin. Expression of the mRNA for neurosin was seen in neurons in the gray matter, and in Microglial cells in the white matter. In AD, the intensity of the signal for neurosin mRNA in the gray matter was decreased compared with normal control brains. The relative levels of neurosin mRNA in AD brains, measured by RT-PCR, were lower than those in controls. These results suggest that in human brain neurosin plays various physiological roles, and that in AD this molecule, like other serine proteases, may have a role in the degradation of such substances as beta-amyloid protein

  257. Ogawa O, Umegaki H, Sumi D, Hayashi T, Nakamura A, Thakur NK, Yoshimura J, Endo H, Iguchi A (2000) Inhibition of inducible nitric oxide synthase gene expression by indomethacin or ibuprofen in beta-amyloid protein-stimulated J774 cells. Eur.J.Pharmacol. 408:137-141
    Abstract: Recent studies show that a mononuclear phagocyte lineage, including Microglia, plays a possible role in the pathogenesis of Alzheimer's disease through nitric oxide (NO)-mediated neurotoxicity. Epidemiological studies show that nonsteroidal anti-inflammatory drugs (NSAIDs) have a protective effect against Alzheimer's disease. Based on these observations, it has been hypothesized that an anti-Alzheimer's disease effect of NSAIDs could result from the inhibition of NO synthesis. We report here that indomethacin or ibuprofen dose-dependently reduce beta-amyloid protein and interferon-gamma-induced NO production, accompanied by an inhibition of inducible nitric oxide synthase mRNA expression in J774 cells, a murine macrophage cell line. Aspirin, however, does not produce such an effect, suggesting that the cyclooxygenases pathway is not involved in the inhibitory effects of NSAIDs on beta-amyloid protein and interferon-gamma-induced NO production in J774 cells

  258. Overmyer M, Kraszpulski M, Helisalmi S, Soininen H, Alafuzoff I (2000) DNA fragmentation, gliosis and histological hallmarks of Alzheimer's disease. Acta Neuropathol.(Berl) 100:681-687
    Abstract: The extent of DNA fragmentation analysed using the TUNEL technique was evaluated in post-mortem human brain tissue. Twenty-four patients with clinical and histopathological diagnosis of Alzheimer's disease (AD) and a short post-mortem delay were analysed. We report an increase in the count of TUNEL-labelled cells as the pathology of AD intensifies. Our results point out a significant correlation between neurofibrillary tangle and senile/neuritic plaque score and TUNEL-labelled cells. Patients with two copies of apolipoprotein (Apo) Eepsilon4 allele had highest number of histopathological hallmarks lesions of AD, whereas the ApoE genotype did not significantly influence the density of TUNEL-positive cells. No significant correlation was found between beta-amyloid protein load and TUNEL-labelled cells. There was no relationship between the age at death, age at onset, extent of astrogliosis or microgliosis and TUNEL-labelled cells in our material

  259. Reynolds WF, Hiltunen M, Pirskanen M, Mannermaa A, Helisalmi S, Lehtovirta M, Alafuzoff I, Soininen H (2000) MPO and APOEepsilon4 polymorphisms interact to increase risk for AD in Finnish males. Neurology 55:1284-1290
    Abstract: BACKGROUND: Myeloperoxidase (MPO) is present in senile plaques and surrounding reactive Microglia, but not in normal brain parenchyma. MPO in plaques is highest in APOE epsilon4 carriers, suggesting a functional interaction. An MPO promoter polymorphism (-463G/A) linked to increased MPO expression has been associated with increased risk of AD. METHODS: To further define the possible interaction of MPO and APOE epsilon4, we examined 127 patients with AD and 174 controls from a genetically homogeneous Finnish population. RESULTS: A significantly higher percentage of male patients with AD carried the MPO A and APOE epsilon4 alleles relative to men carrying neither allele (p < 0.001; OR, 11.4; 95% CI, 3.6 to 6.7). Male APOE epsilon4 carriers lacking the MPO A allele had an OR of 3.0 (p = 0.01; 95% CI, 1.3 to 6.9), indicating that MPO A enhances AD risk by 3.8-fold. Age at onset was lower in men carrying the MPO A and APOE epsilon4 alleles (Kaplan-Meier survival analysis; p = 0.01). Also, the MPO AA genotype was associated with selective mortality in men, but not in women. AA genotypes were absent from 159 male patients with AD and controls, representing the expected 5% to 6% in women and male controls younger than age 20. The -463A creates an estrogen receptor binding site that may contribute to these gender differences. CONCLUSIONS: MPO A and APOE epsilon4 alleles interact to increase the risk of AD in men but not in women in this Finnish cohort

  260. Rozemuller AJ, Eikelenboom P, Theeuwes JW, Jansen Steur EN, de Vos RA (2000) Activated Microglial cells and complement factors are unrelated to cortical Lewy bodies. Acta Neuropathol.(Berl) 100:701-708
    Abstract: Inflammatory mechanisms have been demonstrated in Alzheimer's disease (AD) but their presence in other neurodegenerative disorders is not well documented. Complement factors and activated Microglia have been reported in the substantia nigra of Parkinson's disease (PD). In the present study we investigated the cingulate gyrus of 25 autopsied patients with clinically and neuropathologically well-documented PD, with or without dementia, for the presence of (activated) Microglial cells and their relation with Lewy body (LB)-bearing neurons. In addition, we studied the presence of complement factors in LBs. Of the 25 patient, 15 were clinically demented, fulfilling criteria for dementia with LBs (DLB); 7 also fulfilled CERAD morphological criteria for probable or definite Alzheimer type of dementia. Microglia clustering was seen around congophilic plaques with or without tau pathology. Microglial cells were not associated with LB-bearing neurons or noncongophilic plaques. The cortex of DLB patients without AD plaques did not show more Microglial cells than the cortex of non-demented controls. The number of Microglia was the lowest in young control patients who died immediately after trauma. Complement factor C3d was occasionally seen in diffusely ubiquinated neurons but late complement factors were not detected in these neurons. Double staining for complement and alpha-synuclein was negative, suggesting the absence of complement in LBs. In contrast, AD plaques in the same sections showed complement factors C3c, C3d, C1q and C5-9. In conclusion, we have found no evidence that inflammatory mechanism are involved in LB formation in cerebral cortex

  261. Samatovicz RA (2000) Genetics and brain injury: apolipoprotein E. J.Head Trauma Rehabil. 15:869-874
    Abstract: Apolipoprotein E (apo E) is a lipoprotein produced by astrocytes and Microglia and has a proposed role in transporting lipids to injured neurons. There are three known isoforms of apo E, coded for by the APOE epsilon2, APOE epsilon3, and APOE epsilon4 genes. The APOE epsilon4 genotype has been implicated as a risk factor for Alzheimer's disease. Recent studies have suggested that APOE epsilon4 may influence the central nervous system's response to injury. This article presents an overview of the relationship between apo E, Alzheimer's disease, and head injury and reviews recent studies implicating APOE epsilon4 as a possible genetic determinant in recovery from head injury

  262. Satoh J, Kuroda Y (2000) Amyloid precursor protein beta-secretase (BACE) mRNA expression in human neural cell lines following induction of neuronal differentiation and exposure to cytokines and growth factors. Neuropathology. 20:289-296
    Abstract: Recently, a novel amyloid precursor protein beta-secretase (designated BACE) was identified. Because activated Microglia and astrocytes play a role in amyloidogenesis in Alzheimer's disease, the constitutive and glial cytokine/growth factor-regulated expression of BACE was studied in human neural cell lines. By reverse transcription-polymerase chain reaction (RT-PCR) analysis, BACE mRNA expression was identified in various human neural and non-neural cell lines. By northern blot analysis, the expression of BACE mRNA composed of five distinct transcripts (>8.0, 7.0, 6.0, 4.4 and 2.6 kb) was elevated markedly in NTera2 teratocarcinoma cells following retinoic acid-induced neuronal differentiation. But the levels of three major BACE mRNA species (7.0, 6.0 and 4.4 kb) were not significantly altered in NTera2-derived neurons, SK-N-SH neuroblastoma or U-373MG astrocytoma following exposure to tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, interferon-gamma, transforming growth factor-beta1, epidermal growth factor, basic fibroblast growth factor, brain-derived neurotrophic factor, dibutyryl cyclic adenosine monophosphate or phorbol 12-myristate 13-acetate. These results indicate that BACE mRNA is expressed constitutively in human neural cells and its expression is upregulated during neuronal differentiation, but it is unlikely to be regulated by activated glia-derived cytokines and growth factors

  263. Scali C, Prosperi C, Vannucchi MG, Pepeu G, Casamenti F (2000) Brain inflammatory reaction in an animal model of neuronal degeneration and its modulation by an anti-inflammatory drug: implication in Alzheimer's disease. Eur.J.Neurosci. 12:1900-1912
    Abstract: Brain inflammatory processes underlie the pathogenesis of Alzheimer's disease, and nonsteroidal anti-inflammatory drugs have a protective effect in the disease. The aim of this study was to characterize in vivo in the rat brain the inflammatory reaction in response to excitotoxic insult and to investigate the efficacy of nimesulide treatment. Quisqualic acid was injected into the right nucleus basalis of rats. The excitotoxin induced cholinergic degeneration, an intense glial reaction and the production of inflammatory mediators. Three hours after injection, a five-fold elevation in the concentration of interleukin-1beta in the injected area was observed. This elevation was reduced by 50% by nimesulide (10 mg/kg, i.m.) pretreatment. Electron microscope examination and immunocytochemical staining revealed an intense activation of Microglia and astrocytes at both 24 h and 7 days after injection. Cyclooxygenase-2-immunoreactivity was induced in the blood vessels of the injected hemisphere in perivascular Microglial and endothelial cells 24 h after injection. Seven days postinjection, a cyclooxygenase-2-positive signal was induced in the parenchymal Microglia and large amounts of prostaglandin-E2 were measured in the injected area. Twenty-four hours and 7 days after injection, many inducible nitric oxide synthase-positive cells and a high level of nitrite were detected at the injection site. Seven days of nimesulide (10 mg/kg/day, i.m.) treatment strongly attenuated the Microglial reaction, reduced the number of inducible nitric oxide synthase-positive cells and completely abolished the increase in prostaglandin-E2 formation. These data provide valuable support in vivo for the potential efficacy of cyclooxygenase-2 inhibitors in Alzheimer's disease therapy

  264. Schubert P, Morino T, Miyazaki H, Ogata T, Nakamura Y, Marchini C, Ferroni S (2000) Cascading glia reactions: a common pathomechanism and its differentiated control by cyclic nucleotide signaling. Ann.N.Y.Acad.Sci. 903:24-33
    Abstract: A pathological glia activation, stimulated by inflammatory proteins, beta-amyloid, or brain ischemia, is discussed as a common pathogenic factor for progressive nerve cell damage in vascular and Alzheimer dementia. A critical point seems to be reached, if the cytokine-controlled Microglial upregulation causes a secondary activation of astrocytes which loose the negative feedback control, are forced to give up their physiological buffering function, and may add to neuronal damage by the release of nitric oxide (NO) and by promoting toxic beta-amyloid formation. A strengthening of the cyclic adenosine-5',3'-monophosphate (cAMP) signaling exerted a differential inhibition of the stimulatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) released from cultured rat Microglia, but maintained the negative feedback signal IL-6; cAMP inhibited also the release of free oxygen radicals (OR) but not of NO. Reinforcement of the NO-induced cyclic guanosine monophosphate (cGMP) increase by blockade of the phosphodiesterase (PDE) subtype-5 with propentofylline counterbalanced the toxic NO action that causes with OR neuronal damage by peroxynitrate formation. In rat cultured astrocytes, a prolonged cAMP elevation favored cell differentiation, the expression of a mature ion channel patter, and an improvement of the extracellular glutamate uptake. Cyclic AMP signaling could be strengthened by PDE blockade and by raising extracellular adenosine, which stimulates A2 receptor-mediated cAMP synthesis. Via an A1 receptor-mediated effect, elevated adenosine was found to overcome a deficient intracellular calcium mobilization resulting from an impaired muscarinic signaling at pathologically decreased acetylcholine concentrations. We suggest that pharmaca, which elevate extracellular adenosine and/or block the degradation of cyclic nucleotides, may be used to counteract glia-related neuronal damage in dementing processes

  265. Sheffield LG, Marquis JG, Berman NE (2000) Regional distribution of cortical Microglia parallels that of neurofibrillary tangles in Alzheimer's disease. Neurosci.Lett. 285:165-168
    Abstract: It has been postulated that Microglia contribute to the development of neurofibrillary tangles (NFT) in Alzheimer's disease (AD). We compared the distribution of Microglia with that of NFT in both AD and non-AD cases. In AD cases, we found that the extent of area covered by Ricinus communic agglutinin-1 labeled Microglia generally paralleled NFT frequency and distribution. Microglia occupied the greatest area in tangle-rich periallocortex/allocortex, a lesser area in association cortex, and the smallest area in tangle-poor primary cortex. Interestingly, this pattern was also present in non-AD cases where there were few to no NFT. These findings suggest that regional variations in Microglial distribution may constitute, at least in part, a template for the development of NFT

  266. Shepherd CE, Thiel E, McCann H, Harding AJ, Halliday GM (2000) Cortical inflammation in Alzheimer disease but not dementia with Lewy bodies. Arch.Neurol. 57:817-822
    Abstract: BACKGROUND: There have been no previous studies on the role of inflammation in the brain for the second most common dementing disorder, dementia with Lewy bodies. OBJECTIVE: To investigate the degree of cortical inflammation in dementia with Lewy bodies (DLB) compared with Alzheimer disease (AD) and control brains. DESIGN AND MAIN OUTCOME MEASURES: Post-mortem tissue collection from a brain donor program using standardized diagnostic criteria. Brains collected from January 1, 1993, through December 31, 1996, were screened and selected only for the presence or absence of tau neuritic plaques. Results of immunohistochemistry for HLA-DR were quantified using area fraction counts. Counts were performed by investigators who were unaware of the diagnosis. Results were compared across groups using analysis of variance and posthoc testing. SETTING: A medical research institute in Sydney, Australia. PATIENTS: Eight brains with DLB and without the tau neuritic plaques typical of AD, 10 brains with AD and no Lewy bodies, and 11 nondemented controls without significant neuropathological features were selected from a consecutive sample. RESULTS: Compared with AD, DLB demonstrated significantly less inflammation in the form of HLA-DR-reactive Microglia in all cortical regions (P<.001, posthoc). The level of inflammation in DLB was comparable to that seen in controls (P=.54, post hoc). CONCLUSIONS: Inflammation appears related to the tau neuritic plaques of AD. Despite similar clinical presentations, therapeutic anti-inflammatory strategies are not likely to be effective for pure DLB. Arch Neurol. 2000

  267. Shimohama S, Tanino H, Kawakami N, Okamura N, Kodama H, Yamaguchi T, Hayakawa T, Nunomura A, Chiba S, Perry G, Smith MA, Fujimoto S (2000) Activation of NADPH oxidase in Alzheimer's disease brains. Biochem.Biophys.Res.Commun. 273:5-9
    Abstract: The present study is the first to show that superoxide (O(-)(2)) forming NADPH oxidase is activated in Alzheimer's disease (AD) brains by demonstrating the marked translocation of the cytosolic factors p47-phox and p67-phox to the membrane. In conjunction with a recent in vitro study showing that amyloid beta activates O(-)(2) forming NADPH oxidase in Microglia, where these phox proteins are localized in this study, the present results suggest that, in AD, NADPH oxidase is activated in Microglia, resulting in the formation of reactive oxygen species which can be toxic to neighboring neurons in AD

  268. Shoham S, Youdim MB (2000) Iron involvement in neural damage and microgliosis in models of neurodegenerative diseases. Cell Mol.Biol.(Noisy.-le-grand) 46:743-760
    Abstract: In several neurodegenerative diseases, iron accumulates at sites of brain pathology. Since post-mortem examination cannot distinguish whether iron accumulation caused the damage or resulted from damage, it is necessary to manipulate iron in animal and tissue culture models to assess its causal role(s). However, only in models of Parkinson's disease and of global ischemia, iron deprivation (ID) or iron-chelators have been used to protect from damage. In these studies, documentation of microgliosis was not performed even though several lines of evidence converge to suggest that activation of Microglia is an important source of oxidative stress. In the kainate model of epilepsy, we found that ID protected the olfactory cortex, thalamus and hippocampus and attenuated microgliosis, whereas iron supplementation to ID rats increased damage and microgliosis in the above regions. In the hilus of the hippocampal dentate gyrus, even though no cell loss was observed, ID attenuated microgliosis and iron-supplementation increased it. Thus there is a tight relationship between iron and microgliosis. In addition, iron+zinc supplementation dramatically increased damage to hippocampal CA1 whereas zinc supplementation alone had no effect. This study demonstrates an anatomically unique interaction of iron and zinc, which may lead to new insights to neurodegeneration in epilepsy

  269. Sigurdsson EM, Permanne B, Soto C, Wisniewski T, Frangione B (2000) In vivo reversal of amyloid-beta lesions in rat brain. J.Neuropathol.Exp.Neurol. 59:11-17
    Abstract: Cerebral amyloid-beta (Abeta) deposition is central to the neuropathological definition of Alzheimer disease (AD) with Abeta related toxicity being linked to its beta-sheet conformation and/or aggregation. We show that a beta-sheet breaker peptide (iAbeta5) dose-dependently and reproducibly induced in vivo disassembly of fibrillar amyloid deposits, with control peptides having no effect. The iAbeta5-induced disassembly prevented and/or reversed neuronal shrinkage caused by Abeta and reduced the extent of interleukin-1beta positive Microglia-like cells that surround the Abeta deposits. These findings suggest that beta-sheet breakers, such as iAbeta5 or similar peptidomimetic compounds, may be useful for reducing the size and/or number of cerebral amyloid plaques in AD, and subsequently diminishing Abeta-related histopathology

  270. Simic G, Lucassen PJ, Krsnik Z, Kruslin B, Kostovic I, Winblad B, Bogdanovi (2000) nNOS expression in reactive astrocytes correlates with increased cell death related DNA damage in the hippocampus and entorhinal cortex in Alzheimer's disease. Exp.Neurol. 165:12-26
    Abstract: The immunocytochemical distribution of the neuronal form of nitric oxide synthase (nNOS) was compared with neuropathological changes and with cell death related DNA damage (as revealed by in situ end labeling, ISEL) in the hippocampal formation and entorhinal cortex of 12 age-matched control subjects and 12 Alzheimer's disease (AD) patients. Unlike controls, numerous nNOS-positive reactive astrocytes were found in AD patients around beta-amyloid plaques in CA1 and subiculum and at the places of clear and overt neuron loss, particularly in the entorhinal cortex layer II and CA4. This is the first evidence of nNOS-like immunoreactivity in reactive astrocytes in AD. In contrast to controls, in all but one AD subject, large numbers of ISEL-positive neuronal nuclei and Microglial cells were found in the CA1 and CA4 regions and subiculum. Semiquantitative analysis showed that neuronal DNA fragmentation in AD match with the distribution of nNOS-expressing reactive astroglial cells in CA1 (r = 0.74, P < 0.01) and CA4 (r = 0.58, P < 0.05). A portion of the nNOS-positive CA2/CA3 pyramidal neurons was found to be spared even in the most affected hippocampi. A significant inverse correlation between nNOS expression and immunoreactivity to abnormally phosphorylated tau proteins (as revealed by AT8 monoclonal antibody) in perikarya of these CA2/3 neurons (r = -0.85, P < 0.01) suggests that nNOS expression may provide selective resistance to neuronal degeneration in AD. In conclusion, our results imply that an upregulated production of NO by reactive astrocytes may play a key role in the pathogenesis of AD

  271. Stoltzner SE, Grenfell TJ, Mori C, Wisniewski KE, Wisniewski TM, Selkoe DJ, Lemere CA (2000) Temporal accrual of complement proteins in amyloid plaques in Down's syndrome with Alzheimer's disease. Am.J.Pathol. 156:489-499
    Abstract: The complement system constitutes a series of enzymatic steps involved in the inflammatory response and is activated in Alzheimer's disease (AD). Using Down's syndrome (DS) brains as a temporal model for the progression of AD, we examined components of the complement cascade and their relationship to other principal events in AD pathology: Abeta42 deposition, neuritic changes, neurofibrillary tangles (NFTs), and gliosis (reactive astrocytes, activated Microglia). Adjacent sections of frontal cortex from 24 DS subjects ranging in age from 12 to 73 years were immunohistochemically examined for immunoreactivity (IR) of classical complement proteins (Clq and C3), markers indicating activation of complement (C4d and C5b-9), the complement inhibitor apolipoprotein J (apo J), and markers of AD neuropathology. Abeta42-labeled diffuse plaques were first detected in a 12-year-old DS subject and were not labeled by any of the complement antibodies. Colocalization of Abeta42 with Clq, C3, C4d, and/or apo J was first detected in compacted plaques in the brain of a 15-year-old DS patient with features of mature AD pathology, such as reactive astrocytes, activated Microglia, dystrophic neurites, and a few NFTs. IR for C4d and C5b-9 (membrane attack complex, MAC) was observed in small numbers of plaque-associated dystrophic neurites and in focal regions of pyramidal neurons in this 15-year-old. The only other young (</=30 years) DS brain to show extensive complement IR was that of a 29-year-old DS subject who also displayed the full range of AD neuropathological features. All middle-aged and old DS brains showed IR for Clq and C3, primarily in compacted plaques. In these cases, C4d IR was found in a subset of Abeta42 plaques and, along with C5b-9 IR, was localized to dystrophic neurites in a subset of neuritic plaques, neurons, and some NFTs. Our data suggest that in AD and DS, the classical complement cascade is activated after compaction of Abeta42 deposits and, in some instances, can progress to the local neuronal expression of the MAC as a response to Abeta plaque maturation

  272. Taguchi J, Fujii A, Fujino Y, Tsujioka Y, Takahashi M, Tsuboi Y, Wada I, Yamada T (2000) Different expression of calreticulin and immunoglobulin binding protein in Alzheimer's disease brain. Acta Neuropathol.(Berl) 100:153-160
    Abstract: Both calreticulin (CRT) and immunoglobulin binding protein (Bip) have a role in the folding and assembly of oligomeric membrane proteins in the endoplasmic reticulum (ER). Recent studies have demonstrated the generation of beta-amyloid protein (Abeta) 1-42, a key peptide for amyloid deposits, in the ER. We, therefore, examined the localization and expression of CRT, Bip and their mRNA by immunohistochemistry, Western blot, in situ hybridization and semiquantitative reverse transcription polymerase chain reaction (RT-PCR) in both neurologically normal and Alzheimer's disease (AD) brains. Two polyclonal anti-CRT antibodies gave similar positive staining of CRT in neurons and glia. In neuronal cells, the cytoplasm, nucleoli and their processes were positive for CRT. In glial cells, perinuclear staining was frequently seen and the processes of some glial cells were also stained. In AD, these antibodies stained clearly damaged neurons but the number and the intensity of positive cells were decreased compared to controls. Processes of Microglial cells were markedly positive in the AD white matter. Western blots using an anti-CRT antibody showed significantly lower immunoreactive bands in AD than control brains. By in situ hybridization, the number of neurons which express the CRT mRNA was less in AD than in controls. Using RT-PCR, the relative levels of the CRT mRNA in AD brains were also found to be significantly lower than those in controls. On the other hand, the number of Bip-positive cell, the production of Bip and the expression of mRNA for Bip did not differ between control and AD brains. These results suggest that CRT may be a multifunctional protein in human brain, and that the weak expression of CRT and the positive staining of Microglial processes in AD brain may be part of the pathological processes in AD

  273. Tan J, Town T, Mullan M (2000) CD45 inhibits CD40L-induced Microglial activation via negative regulation of the Src/p44/42 MAPK pathway. J.Biol.Chem. 275:37224-37231
    Abstract: It has been reported that ligation of CD40 with CD40 ligand (CD40L) results in Microglial activation as evidenced by p44/42 mitogen-activated protein kinase (MAPK) dependent tumor necrosis factor alpha (TNF-alpha) production. Previous studies have shown that CD45, a functional transmembrane protein-tyrosine phosphatase, is constitutively expressed at moderate levels on Microglial cells and this expression is greatly elevated on activated Microglia. To investigate the possibility that CD45 might modulate CD40L-induced Microglial activation, we treated primary cultured Microglial cells with CD40L and anti-CD45 antibody. Data show that cross-linking of CD45 markedly inhibits CD40L-induced activity of the Src family kinases Lck and Lyn. Further, co-treatment of Microglia with CD40L and anti-CD45 antibody results in significant inhibition of Microglial TNF-alpha production through inhibition of p44/42 MAPK activity, a downstream signaling event resulting from Src activation. Accordingly, primary cultured Microglial cells from mice deficient in CD45 demonstrate hyper-responsiveness to ligation of CD40, as evidenced by increased p44/42 MAPK activation and TNF-alpha production. Taken together, these results show that CD45 plays a novel role in suppressing CD40L-induced Microglial activation via negative regulation of the Src/p44/42 MAPK cascade

  274. Tan J, Town T, Mori T, Wu Y, Saxe M, Crawford F, Mullan M (2000) CD45 opposes beta-amyloid peptide-induced Microglial activation via inhibition of p44/42 mitogen-activated protein kinase. J.Neurosci. 20:7587-7594
    Abstract: Reactive Microglia have been suggested to play a role in the Alzheimer's disease (AD) process, and previous studies have shown that expression of CD45, a membrane-bound protein-tyrosine phosphatase (PTP), is elevated in Microglia in AD brain compared with controls. To investigate the possible role of CD45 in Microglial responsiveness to beta-amyloid (Abeta) peptides, we first co-treated primary cultured Microglia with a tyrosine phosphatase inhibitor [potassium bisperoxo (1,10-phenanthroline) oxovanadate (phen), 5 micrometer] and freshly solubilized Abeta peptides (1000 nm). Data show synergistic induction of Microglial activation as evidenced by tumor necrosis factor alpha (TNF-alpha) production and nitric oxide (NO) release, both of which we show to be dependent on activation of p44/42 mitogen-activated protein kinase (MAPK). Furthermore, co-treatment with phen and Abeta peptides results in Microglia-induced neuronal cell injury. Stimulation of Microglial CD45 by anti-CD45 antibody markedly inhibits these effects via inhibition of p44/42 MAPK, suggesting that CD45 is a negative regulator of Microglial activation. Accordingly, primary cultured Microglia from CD45-deficient mice demonstrate hyper-responsiveness to Abeta, as evidenced by TNF-alpha release, NO production, and neuronal injury after stimulation with Abeta peptides. As a validation of these findings in vivo, brains from a transgenic mouse model of AD [transgenic Swedish APP-overexpressing (Tg APP(sw)) mice] deficient for CD45 demonstrate markedly increased production of TNF-alpha compared with Tg APP(sw) mice. Taken together, these results suggest that therapeutic agents that stimulate the CD45 PTP signaling pathway may be effective in suppressing Microglial activation associated with AD

  275. Terry RD (2000) Cell death or synaptic loss in Alzheimer disease. J.Neuropathol.Exp.Neurol. 59:1118-1119
    Abstract: It is an erroneous but common assumption that loss of neuronal perikarya causes the cognitive change in Alzheimer disease. Neither are senile plaques nor neurofibrillary tangles primarily to blame. In fact, it is the loss of synaptic contact that leads directly to the personal devastation. The death of neocortical synapses in the neuropil between plaques is probably the factor that activates the Microglia

  276. Togo T, Akiyama H, Kondo H, Ikeda K, Kato M, Iseki E, Kosaka K (2000) Expression of CD40 in the brain of Alzheimer's disease and other neurological diseases. Brain Res. 885:117-121
    Abstract: We have investigated immunohistochemically the expression of CD40 in post-mortem human brain tissues. In control brain, the blood vessels were stained weakly for CD40. Vascular expression of CD40 was enhanced in the lesions of Alzheimer's disease and some other neurological diseases. In such diseases, reactive Microglia were also positive for CD40. The results of this study suggest that CD40 expression by Microglia is up-regulated upon a variety of brain insults and is not limited to lesions with amyloid beta-protein deposits

  277. Trieu VN, Uckun FM (2000) Apolipoprotein E and apolipoprotein D expression in a murine model of singlet oxygen-induced cerebral stroke. Biochem.Biophys.Res.Commun. 268:835-841
    Abstract: Apolipoprotein E (apoE)-deficient mice exhibit neuronal abnormalities similar to those in Alzheimer's disease and enhanced sensitivity to stroke-associated injuries. Here, we show that apoE deficiency results in impaired Microglia/macrophage recruitment and accumulation after cerebral infarct. Astrogliosis and apolipoprotein D (apoD) expression are unaffected, suggesting that the neurological abnormalities of apoE-deficient mice could be due to impaired Microglia/macrophage recruitment/accumulation, which is important for the clearance of neurodegenerative products via reverse cholesterol transport. To our knowledge, the results presented herein provide the first experimental evidence that brain Microglia/macrophage recruitment/accumulation is affected by apoE deficiency. The insights gained from this study should facilitate the elucidation of the role of apoE in neurological disorders such as dementia with stroke and Alzheimer's disease

  278. Vekrellis K, Ye Z, Qiu WQ, Walsh D, Hartley D, Chesneau V, Rosner MR, Selkoe DJ (2000) Neurons regulate extracellular levels of amyloid beta-protein via proteolysis by insulin-degrading enzyme. J.Neurosci. 20:1657-1665
    Abstract: Progressive cerebral accumulation of amyloid beta-protein (Abeta) is an early and invariant feature of Alzheimer's disease. Little is known about how Abeta, after being secreted, is degraded and cleared from the extracellular space of the brain. Defective Abeta degradation could be a risk factor for the development of Alzheimer's disease in some subjects. We reported previously that Microglial cells release substantial amounts of an Abeta-degrading protease that, after purification, is indistinguishable from insulin-degrading enzyme (IDE). Here we searched for and characterized a role for IDE in Abeta degradation by neurons, the principal cell type that produces Abeta. Whole cultures of differentiated pheochromocytoma (PC12) cells and primary rat cortical neurons actively degraded endogenously secreted Abeta via IDE. However, unlike that in Microglia, IDE in differentiated neurons was not released but localized to the cell surface, as demonstrated by biotinylation. Undifferentiated PC12 cells released IDE into their medium, whereas after differentiation, IDE was cell associated but still degraded Abeta in the medium. Overexpression of IDE in mammalian cells markedly reduced the steady-state levels of extracellular Abeta(40) and Abeta(42), and the catalytic site mutation (E111Q) abolished this effect. We observed a novel membrane-associated form of IDE that is approximately 5 kDa larger than the known cytosolic form in a variety of cells, including differentiated PC12 cells. Our results support a principal role for membrane-associated and secreted IDE isoforms in the degradation and clearance of naturally secreted Abeta by neurons and Microglia

  279. Webster SD, Yang AJ, Margol L, Garzon-Rodriguez W, Glabe CG, Tenner AJ (2000) Complement component C1q modulates the phagocytosis of Abeta by Microglia. Exp.Neurol. 161:127-138
    Abstract: Recent studies showing that Microglia internalize the amyloid beta-peptide (Abeta) suggest that these cells have the potential for clearing Abeta deposits in Alzheimer's disease, and mechanisms that regulate the removal of Abeta may therefore be of clinical interest. Previous studies from this laboratory showing that C1q enhances phagocytosis of cellular targets by rat Microglia prompted the current investigations characterizing the effects of C1q on Microglial phagocytosis of Abeta. Microglia were shown to phagocytose Abeta1-42, in agreement with observations of other investigators. Uptake of Abeta1-42 was observed for concentrations of 5-50 microM, and phagocytosis of peptides containing (14)C or fluorescein (FM) labels was not affected by the interaction of Microglia with C1q-coated surfaces. However, inclusion of C1q (125 nM-1.4 microM) in solutions of 50 microM Abeta1-42 inhibited the uptake of (14)C-Abeta1-42 and FM-Abeta1-42, suggesting that C1q blocks the interaction of Abeta with Microglia. Uptake of Abeta was partially blocked by the scavenger receptor ligands polyinosinic acid and maleylated BSA. Inhibition of Abeta uptake by C1q may contribute to the accumulation of fibrillar, C1q-containing plaques that occurs in parallel with disease progression. These data suggest that mechanisms which interfere with the binding of C1q to Abeta may be of therapeutic value both through inhibition of the inflammatory events resulting from complement activation and via altered access of Abeta sites necessary for ingestion by Microglia

  280. Wegiel J, Wang KC, Tarnawski M, Lach B (2000) Microglia cells are the driving force in fibrillar plaque formation, whereas astrocytes are a leading factor in plague degradation. Acta Neuropathol.(Berl) 100:356-364
    Abstract: Ultrastructural three-dimensional reconstruction of human classical plaques in different stages of development shows that Microglial cells are the major factor driving plaque formation by fibrillar amyloid-beta (Abeta) deposition. The amount of fibrillar Abeta released by Microglial cells and the area of direct contact between amyloid and neuron determine the extent of dystrophic changes in neuronal processes and synapses. The volume of hypertrophic astrocytic processes separating fibrillar amyloid from neuron is a measure of the protective activation of astrocytes. On the bases of the volume of amyloid star, Microglial cells, dystrophic neurites, and hypertrophic astrocytic processes, and spatial relationships between plaque components, three stages in classical plaque development have been distinguished: early, mature, and late. In early plaque, the leading pathology is fibrillar Abeta deposition by Microglial cells with amyloid star formation. The mature plaque is characterized by a balance between amyloid production, neuronal dystrophy, and astrocyte hypertrophy. In late classical plaque, Microglial cells retract and expose neuropil on direct contact with amyloid star, enhancing both dystrophic changes in neurons and hypertrophic changes in astrocytes. In late plaques, activation of astrocytes predominates. They degrade amyloid star and peripheral amyloid wisps. The effect of these changes is classical plaque degradation to fibrillar primitive and finally to nonfibrillar, diffuse-like plaques

  281. Weiner HL, Lemere CA, Maron R, Spooner ET, Grenfell TJ, Mori C, Issazadeh S, Hancock WW, Selkoe DJ (2000) Nasal administration of amyloid-beta peptide decreases cerebral amyloid burden in a mouse model of Alzheimer's disease. Ann.Neurol. 48:567-579
    Abstract: Progressive cerebral deposition of amyloid-beta (Abeta) peptide, an early and essential feature of Alzheimer's disease (AD), is accompanied by an inflammatory reaction marked by microgliosis, astrocytosis, and the release of proinflammatory cytokines. Mucosal administration of disease-implicated proteins can induce antigen-specific anti-inflammatory immune responses in mucosal lymphoid tissue which then act systemically. We hypothesized that chronic mucosal administration of Abeta peptide might induce an anti-inflammatory process in AD brain tissue that could beneficially affect the neuropathological findings. To test this hypothesis, we treated PDAPP mice, a transgenic line displaying numerous neuropathological features of AD, between the ages of approximately 5 and approximately 12 months with human Abeta synthetic peptide mucosally each week. We found significant decreases in the cerebral Abeta plaque burden and Abeta42 levels in mice treated intranasally with Abeta peptide versus controls treated with myelin basic protein or left untreated. This lower Abeta burden was associated with decreased local Microglial and astrocytic activation, decreased neuritic dystrophy, serum anti-Abeta antibodies of the IgG1 and IgG2b classes, and mononuclear cells in the brain expressing the anti-inflammatory cytokines interleukin-4, interleukin-10, and tumor growth factor-beta. Our results demonstrate that chronic nasal administration of Abeta peptide can induce an immune response to Abeta that decreases cerebral Abeta deposition, suggesting a novel mucosal immunological approach for the treatment and prevention of AD

  282. Wisniewski HM, Wegiel J, Vorbrodt AW, Mazur-Kolecka B, Frackowiak J (2000) Role of perivascular cells and myocytes in vascular amyloidosis. Ann.N.Y.Acad.Sci. 903:6-18
    Abstract: Amyloidogenic processing of amyloid-beta precursor protein (APP) by cells of the brain is the major pathologic component of Alzheimer's disease. Amyloid-beta (A beta) is of heterogeneous origin. Perivascular cells of monocyte-macrophage-Microglial cell lineage produce fibrillar A beta in the wall of capillaries, whereas parenchymal Microglial cells produce fibrillar A beta in the parenchyma of gray matter. Fibrillar A beta deposition by perivascular cells lead to endothelial cell degeneration and death, obliteration of affected capillaries, and reduction of the length of the vascular network. These changes cause local ischemia with neuronal degeneration and death. Smooth muscle cells are the source of A beta in the tunica media of parenchymal and leptomeningeal arteries and veins. Fibrillar A beta in the tunica media of leptomeningeal and parenchymal vessels causes degeneration and necrosis of smooth muscle cells and leads to multiple cortical hemorrhages. Smooth muscle cells isolated from blood vessels with amyloid deposits secrete A beta and accumulate nonfibrillar A beta intracellularly. The amyloidogenic processing of APP can be enhanced by apolipoprotein E, reduced by transthyretin, and modulated by several cytokines

  283. Xu Q, Li Y, Cyras C, Sanan DA, Cordell B (2000) Isolation and characterization of apolipoproteins from murine Microglia. Identification of a low density lipoprotein-like apolipoprotein J-rich but E-poor spherical particle. J.Biol.Chem. 275:31770-31777
    Abstract: Amyloid Abeta deposition is a neuropathologic hallmark of Alzheimer's disease. Activated Microglia are intimately associated with plaques and appear to facilitate Abeta deposition, an event believed to contribute to pathogenesis. It is unclear if Microglia can modulate pathogenesis of Alzheimer's disease by secreting lipoprotein particles. Here we show that cultured BV2 murine Microglial cells, like astrocytes, secrete apolipoprotein E (apoE) and apolipoprotein J (apoJ) in a time-dependent manner. To isolate and identify BV2 Microglial particles, gel filtration chromatography was employed to fractionate BV2-conditioned medium. Analyses by Western blot, lipid determination, electron microscopy, and native gel electrophoresis demonstrate that BV2 Microglial cells release spherical low density lipoprotein (LDL)-like lipid-containing particles rich in apoJ but poor in apoE. These Microglial particles are dissimilar in size, shape, and lipoprotein composition to astrocyte-derived particles. The Microglial-derived particles were tested for functional activity. Under conditions of suppressed de novo cholesterol synthesis, the LDL-like particles effectively rescued primary rat cortical neurons from mevastatin-induced neurotoxicity. The particles were also shown to bind Abeta. We speculate that the LDL-like apoJ-rich apoE-poor Microglial lipoproteins preferentially bind the lipoprotein receptor, recognizing apoJ, which is abundant in the choroid plexus, facilitating Abeta clearance from the brain. BV2 cells also secrete an apoE-rich lipid-poor species that binds Abeta. Consistent with the role of apoE in Abeta fibril formation and deposition, this Microglial species may promote plaque formation

  284. Yoshiyama Y, Arai K, Oki T, Hattori T (2000) Expression of invariant chain and pro-cathepsin L in Alzheimer's brain. Neurosci.Lett. 290:125-128
    Abstract: Inflammatory and immune systems are involved in the pathogenesis of Alzheimer's disease (AD), but those systems in the human brain have not been well identified. Cathepsin L might play a predominant role in the degradation of the invariant chain (Ii), which plays a critical role in antigen presentation to block the antigen-binding site of the major histocompatibility complex class II. We examined the expression of Ii and pro-cathepsin L (pCPL) in AD and normal brains by using immunohistochemistry. Ii expresses only in resting or mildly activated Microglia, whereas pCPL strongly expresses in fully activated Microglia but not in resting or mildly activated Microglia in AD. Normal brain tissues have rarely been stained for Ii or pCPL. These results suggest that the activation of Microglia leads to expression of a complex of Ii and human leukocyte antigen class II at first, and that further activation, which is followed by cluster formation and enlargement of Microglia frequently seen in the AD brain, might cause pCPL expression to degrade Ii. Our study confirmed that Microglia plays a central role in the immune system of the brain, and that an activation of Microglia is involved in the pathogenesis of AD

  285. Akiyama H, Mori H, Saido T, Kondo H, Ikeda K, McGeer PL (1999) Occurrence of the diffuse amyloid beta-protein (Abeta) deposits with numerous Abeta-containing glial cells in the cerebral cortex of patients with Alzheimer's disease. Glia 25:324-331
    Abstract: Diffuse amyloid beta-protein (Abeta) deposits with numerous glial cells containing C-terminal Abeta fragments occur in the cerebral cortex of patients with Alzheimer's disease. By using a panel of antibodies specific for various epitopes in the Abeta peptide, we have investigated the immunohistochemical nature of the diffuse Abeta deposits. The extracellular material contains Abeta with a C-terminus at residue valine40 (Abeta40) as well as residues alanine42/threonine43 (Abeta42). The N-termini include aspartate1, pyroglutamate3, and pyroglutamate11, with pyroglutamate3 being dominant. Microglia and astrocytes in and around these deposits contain intensely staining granules. Most of these granules are negative for antibodies to the N-terminally located sequences of Abeta. These include 6E10 (Abeta1-17), 6F/3D (Abeta8-17), and the N-terminal antibodies specific to aspartate1, pyroglutamate3, and pyroglutamate11. The C-termini of intraglial Abeta are comparable with those of the extracellular deposits. The Microglia and astrocytes have quiescent morphology compared with those associated with senile plaques and other lesions such as ischemia. Complement activation in these deposits is not prominent and often below the sensitivity of immunohistochemical detection. Although factors which may cause this type of deposit remain unclear, lack of strong tissue responses suggests that these deposits are a very early stage of Abeta deposition. They were found only inconsistently and were absent in a number of cases examined in this study. Further analysis of these deposits might provide important clues regarding the accumulation and clearance of Abeta in Alzheimer's disease brain

  286. Alvarez R, Alvarez V, Lahoz CH, Martinez C, Pena J, Sanchez JM, Guisasola LM, Salas-Puig J, Moris G, Vidal JA, Ribacoba R, Menes BB, Uria D, Coto E (1999) Angiotensin converting enzyme and endothelial nitric oxide synthase DNA polymorphisms and late onset Alzheimer's disease. J.Neurol.Neurosurg.Psychiatry 67:733-736
    Abstract: OBJECTIVES: Several lines of evidence suggest that the endothelial constitutive nitric oxide synthase (ecNOS) and angiotensin converting enzyme (ACE) may have a role in Alzheimer's disease. ACE is widely expressed in the brain, and a DNA polymorphism at the ACE gene has been linked to the risk for late onset Alzheimer's disease. Nitric oxide (NO) production by Microglial cells, astrocytes, and brain microvessels is enhanced in patients with Alzheimer's disease. There is a growing evidence that NO is involved in neuronal death in Alzheimer's disease, and the oxidative stress caused by NO in the brain could be a pathogenic mechanism in Alzheimer's disease. The objective was to determine if two DNA polymorphisms at the ecNOS and ACE genes that have been linked with different levels of enzyme expression, have some effect on the risk of developing late onset Alzheimer disease. METHODS: A total of 400 healthy controls younger than 65 years and 350 patients with Alzheimer's disease (average age 72 years) were genotyped for the ACE and ecNOS polymorphisms. To define a possible role for these polymorphisms in longevity 117 healthy controls older than 85 years were also analysed. Genomic DNA was obtained and amplified by polymerase chain reaction, and genotypes were defined following a previously described procedure. Gene and genotype frequencies between patients and controls were compared statistically. RESULTS: Gene and genotype frequencies for the ecNOS and ACE polymorphisms did not differ between both groups of healthy controls (<65 years and >85 years). EcNOS gene and genotype frequencies were similar between patients and controls. There was a slight but significantly increased frequency of the ACE-I allele among patients with Alzheimer's disease compared with controls (p=0.03; OR=1.28, 95%CI= 1.04;1.58). CONCLUSIONS: The ACE-I allele was associated with a slightly increased risk of developing late onset Alzheimer's disease

  287. Benzing WC, Wujek JR, Ward EK, Shaffer D, Ashe KH, Younkin SG, Brunden KR (1999) Evidence for glial-mediated inflammation in aged APP(SW) transgenic mice. Neurobiol.Aging 20:581-589
    Abstract: Chronic expression of inflammatory cytokines, including interleukin-1beta, tumor necrosis factor alpha, and interleukin-6, by glia may underlie the neurodegenerative events that occur within the brains of patients with Alzheimer's disease (AD). The present study determined whether these markers of inflammation could be observed within the brains of Tg(HuAPP695.K670N/M671L)2576 transgenic mice (Tg2576) that have recently been shown to mimic many features of AD. Interleukin-1beta- and tumor necrosis factor alpha-immunopositive Microglia were localized with thioflavine-positive (fibrillar) Abeta deposits. Moreover, interleukin-6 immunoreactive astrocytes surrounded fibrillar Abeta deposits. These findings provide evidence that Tg2576 mice exhibit features of the inflammatory pathology seen in AD and suggest that these mice are a useful animal model for studying the role inflammation may play in this disease

  288. Carrasco J, Giralt M, Molinero A, Penkowa M, Moos T, Hidalgo J (1999) Metallothionein (MT)-III: generation of polyclonal antibodies, comparison with MT-I+II in the freeze lesioned rat brain and in a bioassay with astrocytes, and analysis of Alzheimer's disease brains. J.Neurotrauma 16:1115-1129
    Abstract: Metallothionein-III is a low molecular weight, heavy-metal binding protein expressed mainly in the central nervous system. First identified as a growth inhibitory factor (GIF) of rat cortical neurons in vitro, it has subsequently been shown to be a member of the metallothionein (MT) gene family and renamed as MT-III. In this study we have raised polyclonal antibodies in rabbits against recombinant rat MT-III (rMT-III). The sera obtained reacted specifically against recombinant zinc-and cadmium-saturated rMT-III, and did not cross-react with native rat MT-I and MT-II purified from the liver of zinc injected rats. The specificity of the antibody was also demonstrated in immunocytochemical studies by the elimination of the immunostaining by preincubation of the antibody with brain (but not liver) extracts, and by the results obtained in MT-III null mice. The antibody was used to characterize the putative differences between the rat brain MT isoforms, namely MT-I+II and MT-III, in the freeze lesion model of brain damage, and for developing an ELISA for MT-III suitable for brain samples. In the normal rat brain, MT-III was mostly present primarily in astrocytes. However, lectin staining indicated that MT-III immunoreactivity was also present in Microglia, monocytes and/or macrophages in the leptomeninges and lying adjacent to major vessels. In freeze lesioned rats, both MT-I+II and MT-III immunoreactivities increased in the ipsilateral cortex. The pattern of MT-III immunoreactivity significantly differed from that of MT-I+II, since the latter was evident in both the vicinity of the lesioned tissue and deeper cortical layers, whereas that of the former was located only in the deeper cortical layers. This suggests different roles for these MT isoforms, and indeed in a new bioassay measuring astrocyte migration in vitro, rMT-III promoted migration to a higher extent than MT-I+II. Thus, MT-III could not only affect neuronal sprouting as previously suggested, but also astrocyte function. Finally, MT-III protein levels of patients with Alzheimer's disease (AD) were, if anything, increased when compared with similarly aged control brains, which was in agreement with the significantly increased MT-III mRNA levels of AD brains

  289. Casamenti F, Prosperi C, Scali C, Giovannelli L, Colivicchi MA, Faussone-Pellegrini MS, Pepeu G (1999) Interleukin-1beta activates forebrain glial cells and increases nitric oxide production and cortical glutamate and GABA release in vivo: implications for Alzheimer's disease. Neuroscience 91:831-842
    Abstract: Interleukin-1beta (10 U) was injected into the nucleus basalis of adult male Wistar rats. The inflammation-induced changes in glial cell morphology and expression of inducible nitric oxide synthase in the injected area, the release of acetylcholine, GABA and glutamate from the ipsilateral cortex, the production of nitrite levels in the injected area and ipsilateral cortex, and changes in motor activity were investigated. Saline-injected rats were used as control. Interleukin-1beta induced an activation of both Microglia and astrocytes which was already evident 24 h after injection. Seven days after injection, many reactive Microglial cells and astrocytes were seen in the injected area and in other brain regions of the same hemisphere. Microglia reaction, but not astrocyte activation, disappeared 30 days post-injection. Seven days after interleukin-1beta injection, many cells immunopositive for inducible nitric oxide synthase were found surrounding the injection site. Inducible nitric oxide synthase-positive cells were identified, by double staining immunohistochemistry, in the reactive Microglial cells and, by electron microscope examination, in the perineuronal subpopulation of resident activated Microglia. Microdialysis investigations revealed a transient increase in reactive nitrogen intermediates (at seven days post-injection), a delayed (at 30 days post-injection) increase in GABA and glutamate release, and no changes in acetylcholine release in the ipsilateral cortex in interleukin-1beta, but not saline, injected rats. Inhibition of inducible nitric oxide synthase expression by N(G)-nitro-L-arginine methyl ester administration prevented the increase in nitrogen intermediates and GABA release, but not in glutamate release. Our findings suggest that an inflammatory reaction of the basal forebrain facilitates GABA release through the production of nitric oxide

  290. Chung H, Brazil MI, Soe TT, Maxfield FR (1999) Uptake, degradation, and release of fibrillar and soluble forms of Alzheimer's amyloid beta-peptide by Microglial cells. J.Biol.Chem. 274:32301-32308
    Abstract: Microglia are phagocytic cells that are the main inflammatory response cells of the central nervous system. In Alzheimer's disease brain, activated Microglia are concentrated in regions of compact amyloid deposits that contain the 39-43-amino acid Abeta peptide. We examined the uptake, degradation, and release of small aggregates of fibrillar Abeta (fAbeta) or soluble Abeta (sAbeta) by Microglia. We found that although some degradation of fAbeta was observed over 3 days, no further degradation was observed over the next 9 days. Instead, there was a slow release of intact Abeta. The poor degradation was not due to inhibition of lysosomal function, since the rate of alpha2-macroglobulin degradation was not affected by the presence of fAbeta in the late endosomes/lysosomes. In contrast to fAbeta, internalization of sAbeta was not saturable. After internalization, sAbeta was released rapidly from Microglia, and very little was degraded. These data show that fAbeta and sAbeta interact differently with Microglia but that after internalization a large fraction of both are released without degradation

  291. Di Patre PL, Read SL, Cummings JL, Tomiyasu U, Vartavarian LM, Secor DL, Vinters HV (1999) Progression of clinical deterioration and pathological changes in patients with Alzheimer disease evaluated at biopsy and autopsy. Arch.Neurol. 56:1254-1261
    Abstract: OBJECTIVES: To quantify the progression of senile plaques, neurofibrillary tangles, cerebral amyloid angiopathy, and Microglial activation in the cortex and white matter of patients with Alzheimer disease evaluated at both biopsy and subsequent autopsy and correlate these changes with the progression of neurologic impairment. SETTING: Academic referral center for patient with Alzheimer disease. PATIENTS: Four patients meeting the clinical criteria for Alzheimer disease, enrolled in a pilot study for the evaluation of response to intracerebroventricular administration of bethanechol chloride. The patients were followed up until death occurred and autopsy was performed. RESULTS: All 4 patients had progressive deterioration from the time of biopsy to autopsy (9-11 years). Pathological investigations showed a striking increase in the density of senile plaques and neurofibrillary tangles in 2 of 4 patients from biopsy to autopsy, and a significant increase in Microglial activation in 1 of 4 cases. Severity of cerebral amyloid angiopathy varied significantly among patients, 1 of whom displayed striking amyloid deposition with associated subcortical white matter atrophy. CONCLUSIONS: These unique data demonstrate that the progressive neurologic impairment in Alzheimer disease is accompanied by a significant increase in senile plaque and neurofibrillary tangle counts in the frontal cortex and, possibly in some patients, by increased Microglial cell activation. Cerebral amyloid angiopathy was associated with significant white matter disease

  292. Dickson DW (1999) Microglia in Alzheimer's disease and transgenic models. How close the fit? Am.J.Pathol. 154:1627-1631

  293. Durany N, Munch G, Michel T, Riederer P (1999) Investigations on oxidative stress and therapeutical implications in dementia. Eur.Arch.Psychiatry Clin.Neurosci. 249 Suppl 3:68-73
    Abstract: Alzheimer's disease (AD) is a progressive dementia affecting a large proportion of the aging population. The histopathological changes in AD include neuronal cell death and formation of amyloid plaques and neurofibrillary tangles (NFTs) NFTs are composed of hyperphosphorylated tau protein, and senile plaques contain aggregates of the beta-peptide. There is also evidence that brain tissue in patients with AD is exposed to oxidative stress during the course of the disease. Advanced glycation endproducts (AGEs), which are formed by a non-enzymatic reaction of glucose with long-lived protein deposits, are potentially toxic to the cell, are present in brain plaques in AD, and its extracellular accumulation in AD may be caused by an accelerated oxidation of glycated proteins. The microtubuli-associated protein tau is also subject to intracellular AGE formation. AGEs participate in neuronal death causing direct (chemical) radical production: Glycated proteins produce nearly 50-fold more radicals than non-glycated proteins, and indirect (cellular) radical production: Interaction of AGEs with cells increases oxidative stress. During aging cellular defence mechanisms weaken and the damages to cell constituents accumulate leading to loss of function and finally cell death. The development of drugs for the treatment of AD remains at a very unsatisfying state. However, pharmacological approaches which break the vicious cycles of oxidative stress and neurodegeneration offer new opportunities for the treatment of AD. Theses approaches include AGE-inhibitors, antioxidants, and anti-inflammatory substances, which prevent radical production. AGE inhibitors might be able to stop formation of AGE-modified beta-amyloid deposits, antioxidants are likely to scavenge intracellular and extracellular superoxide radicals and hydrogen peroxide before these radicals damage cell constituents or activate Microglia, and anti-inflammatory drugs attenuating Microglial radical and cytokine production

  294. Fiebich BL, Hofer TJ, Lieb K, Huell M, Butcher RD, Schumann G, Schulze-Osthoff K, Bauer J (1999) The non-steroidal anti-inflammatory drug tepoxalin inhibits interleukin-6 and alpha1-anti-chymotrypsin synthesis in astrocytes by preventing degradation of IkappaB-alpha. Neuropharmacology 38:1325-1333
    Abstract: Tepoxalin is a structurally and functionally novel non-steroidal anti-inflammatory drug (NSAID) with potent anti-inflammatory and analgesic properties. Apart from its inhibitory effect on cyclooxygenase activity, tepoxalin is able to inhibit production of cytokines in peripheral cells outside the CNS. No data, however, are available concerning the effects of this drug in the CNS. Since cytokines such as interleukin-1 (IL-1) or interleukin-6 (IL-6) as well as acute-phase proteins such as alpha1-anti-chymotrypsin (ACT) participate in the etiopathology of Alzheimer's disease (AD), we were interested whether tepoxalin is able to inhibit the synthesis of these immunomodulators in primary rat Microglia and astrocytes as well as in the human astrocytoma cell line U373 MG. We found that tepoxalin markedly inhibits IL-1beta-induced IL-6 and ACT synthesis in astrocytes and the synthesis of IL-1beta and IL-6 in lipopolysaccharide (LPS)-stimulated Microglial cells. Electrophoretic mobility shift and reporter gene assays revealed that tepoxalin exerts its inhibitory effect through the inhibition of nuclear factor kappaB (NF-kappaB), a transcription factor involved in the induction of IL-1, IL-6 and ACT gene expression. We show that inhibition of NF-kappaB activation by tepoxalin is mediated by preventing IkappaB-alpha degradation. Based on this inhibitory effect of tepoxalin on cytokine and ACT synthesis and the documented therapeutic efficacy of NSAIDs in AD, we conclude that tepoxalin may be of therapeutic benefit for the treatment of AD patients and should therefore be tested in clinical trials

  295. Fonseca MI, Head E, Velazquez P, Cotman CW, Tenner AJ (1999) The presence of isoaspartic acid in beta-amyloid plaques indicates plaque age. Exp.Neurol. 157:277-288
    Abstract: Extracellular deposits of fibrillar beta-amyloid are a characteristic neuropathology of Alzheimer's disease (AD). We have developed a novel antibody to a hypothesized "older isomer" of the amyloid protein. This antibody, raised against a synthetic beta-amyloid peptide containing isoaspartic acid at position 7 (isoaspartic-7-Abeta), reacts with isoaspartic-7-Abeta, a nonenzymatic modification found in long-lived proteins. Plaques stained with this antibody are thioflavine positive and are found throughout the frontal and entorhinal cortices of AD cases. In frontal cortex, isoaspartic-7-Abeta plaques are clustered but have a widespread distribution in all cortical layers. Isoaspartic-7-Abeta is found primarily in the core of individual plaques surrounded by nonisomerized amyloid. Activated Microglia are associated with plaques containing isomerized and nonisomerized amyloid. In contrast to AD, isoaspartic-7-Abeta plaques in Down's syndrome (DS) cases are found primarily in the superficial layers of frontal cortex. Using image analysis isoaspartic-7-Abeta deposition was correlated with dementia severity in AD and with age in DS. The results indicate that this antibody against altered aspartyl amyloid could be a useful indicator of the age of amyloid plaques

  296. Garcia dY, Ho A, Damani T, Fillit H, Blum M (1999) Regulation of the heparan sulfate proteoglycan, perlecan, by injury and interleukin-1alpha. J.Neurochem. 73:812-820
    Abstract: Perlecan is a specific proteoglycan that binds to amyloid precursor protein and beta-amyloid peptide, is present within amyloid deposits, and has been implicated in plaque formation. Because plaque formation is associated with local inflammation, we hypothesized that the mechanisms involved in brain inflammatory responses could influence perlecan biosynthesis. To test this hypothesis, we first studied perlecan regulation in mice after inflammation induced by a brain stab wound. Perlecan mRNA and immunoreactivity were both increased 3 days after injury. Interleukin-1alpha (IL-1alpha) is a cytokine induced after injury and plays an important role in inflammation. As such, IL-1alpha may be one of the factors participating in regulating perlecan synthesis. We thus studied perlecan regulation by IL-1alpha, in vivo. Regulation of perlecan mRNA by this cytokine was area-specific, showing up-regulation in hippocampus, whereas in striatum, perlecan mRNA was unchanged. To support this differential regulation of perlecan mRNA by IL-1alpha, basic fibroblast growth factor (bFGF), a growth factor also present in plaques, was studied in parallel. bFGF mRNA did not show any regional difference, being up-regulated in both hippocampus and striatum in vivo. In vitro, both astrocyte and Microglia were immunoreactive for perlecan. Moreover, perlecan mRNA was increased in hippocampal glial cultures after IL-1alpha but not in striatal glia. These results show an increase in perlecan biosynthesis after injury and suggest a specific regulation of perlecan mRNA by IL-1alpha, which depends on brain area. Such regulation may have important implications in the understanding of regional brain variations in amyloid plaque formation

  297. Garlind A, Brauner A, Hojeberg B, Basun H, Schultzberg M (1999) Soluble interleukin-1 receptor type II levels are elevated in cerebrospinal fluid in Alzheimer's disease patients. Brain Res. 826:112-116
    Abstract: Evidence from epidemiological, clinical and experimental studies favour the hypothesis that inflammatory events are part of the neuropathology in Alzheimer's disease. Proinflammatory cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) have been found in activated Microglia in the vicinity of amyloid plaques in Alzheimer's disease brain. In the present study, the levels of soluble IL-1 receptor type II (sIL-1R type II), IL-1 receptor antagonist (IL-1ra), IL-1beta, IL-6 and TNF-alpha were analyzed in cerebrospinal fluid (CSF) samples from Alzheimer's disease patients and control subjects. The levels of sIL-1R type II were significantly higher in CSF from Alzheimer's disease patients than in CSF samples from control subjects (38.5+/-8 pg/ml (mean+/-S.E.M.) vs. 7.9+/-4 pg/ml, p<0.05). Measurements of the proinflammatory cytokines IL-6 and TNF-alpha showed no significant difference between the two groups, and the levels of IL-1beta and IL-1ra in the present material were too low to permit detection. The increased levels of sIL-1R type II may reflect a compensatory mechanism to balance an increased release of IL-1 receptor agonists in the Alzheimer's disease brain

  298. Giulian D (1999) Microglia and the immune pathology of Alzheimer disease. Am.J.Hum.Genet. 65:13-18

  299. Gonzalez-Scarano F, Baltuch G (1999) Microglia as mediators of inflammatory and degenerative diseases. Annu.Rev.Neurosci. 22:219-240
    Abstract: Microglia are the principal immune cells in the central nervous system (CNS) and have a critical role in host defense against invading microorganisms and neoplastic cells. However, as with immune cells in other organs, Microglia may play a dual role, amplifying the effects of inflammation and mediating cellular degeneration as well as protecting the CNS. In entities like human immunodeficiency virus (HIV) infection of the nervous system, Microglia are also critical to viral persistence. In this review we discuss the role of Microglia in three diseases in which their activity is at least partially deleterious: HIV, multiple sclerosis, and Alzheimer's disease

  300. Hesselgesser J, Horuk R (1999) Chemokine and chemokine receptor expression in the central nervous system. J.Neurovirol. 5:13-26
    Abstract: A decade ago several new cytokines were described that orchestrated the activation and migration of immune cells. These newly described cytokines, of which interleukin-8 (IL-8) was a representative member, defined a novel group of molecules called chemokines (chemotactic cytokines). Chemokines are low molecular weight, 8-12 kDa, basic proteins that have been classified into four distinct families, CXC, CC, C and CX3C, based on the position of their first two conserved cysteine residues. The expression and biological function of chemokines along with their cognate receptors have been well described on various subsets of leukocytes. Only more recently have these molecules been described on various cells within the central nervous system. These pro-inflammatory proteins have been implicated in a variety of diseases within the central nervous system from Multiple Sclerosis to AIDS dementia. While chemokines are likely to enhance the evolution of central nervous system inflammatory disorders they also have other roles in normal brain function and development. This review summarizes the role of chemokines and their receptors in the normal and pathophysiological brain

  301. Huang F, Buttini M, Wyss-Coray T, McConlogue L, Kodama T, Pitas RE, Mucke L (1999) Elimination of the class A scavenger receptor does not affect amyloid plaque formation or neurodegeneration in transgenic mice expressing human amyloid protein precursors. Am.J.Pathol. 155:1741-1747
    Abstract: The class A scavenger receptor (SR) is expressed on reactive Microglia surrounding cerebral amyloid plaques in Alzheimer's disease (AD). Interactions between the SR and amyloid beta peptides (Abeta) in Microglial cultures elicit phagocytosis of Abeta aggregates and release of neurotoxins. To assess the role of the SR in amyloid clearance and Abeta-associated neurodegeneration in vivo, we used the platelet-derived growth factor promoter to express human amyloid protein precursors (hAPPs) in neurons of transgenic mice. With increasing age, hAPP mice develop AD-like amyloid plaques. We bred heterozygous hAPP (hAPP(+/-)) mice that were wild type for SR (SR(+/+)) with SR knockout (SR(-/-)) mice. Crosses among the resulting hAPP(+/-)SR(+/-) offspring yielded hAPP(+/-) and hAPP(-/-) littermates that were SR(+/+) or SR(-/-). These second-generation mice were analyzed at 6 and 12 months of age for extent of cerebral amyloid deposition and loss of synaptophysin-immunoreactive presynaptic terminals. hAPP(-/-)SR(-/-) mice showed no lack of SR expression, plaque formation, or synaptic degeneration, indicating that lack of SR expression does not result in significant accumulation of endogenous amyloidogenic or neurotoxic factors. In hAPP(+/-) mice, ablation of SR expression did not alter number, extent, distribution, or age-dependent accumulation of plaques; nor did it affect synaptic degeneration. Our results do not support a critical pathogenic role for Microglial SR expression in neurodegenerative alterations associated with cerebral beta amyloidosis

  302. Johnstone M, Gearing AJ, Miller KM (1999) A central role for astrocytes in the inflammatory response to beta-amyloid; chemokines, cytokines and reactive oxygen species are produced. J.Neuroimmunol. 93:182-193
    Abstract: Alzheimer's disease (AD) is the commonest form of adult onset dementia and is characterised neuropathologically by the accumulation of plaques containing beta-amyloid (A beta) fibrils, reactive astrocytes, activated Microglia, and leukocytes. A beta plays a role in the pathology of AD by directly causing neuronal cytotoxicity and stimulating Microglia to secrete cytokines and reactive oxygen species (ROS) which also damage neurons. Here, we demonstrate that A beta activates astrocytes and oligodendrocytes (the most common cell types in the brain) to produce chemokines, in particular MCP-1 and RANTES, which serve as potent in vitro Microglial and macrophage chemoattractants. Furthermore, we have shown that A beta activates astrocytes to upregulate pro-inflammatory cytokine expression and enhances the production of ROS. We propose therefore that A beta-mediated astrocyte activation initiates an inflammatory cascade which could be targeted for therapeutic intervention in AD

  303. Kalaria RN (1999) Microglia and Alzheimer's disease. Curr.Opin.Hematol. 6:15-24
    Abstract: Microglia play a major role in the cellular response associated with the pathological lesions of Alzheimer's disease. As brain-resident macrophages, Microglia elaborate and operate under several guises that seem reminiscent of circulating and tissue monocytes of the leucocyte repertoire. Although Microglia bear the capacity to synthesize amyloid beta, current evidence is most consistent with their phagocytic role. This largely involves the removal of cerebral amyloid and possibly the transformation of amyloid beta into fibrils. The phagocytic functions also encompass the generation of cytokines, reactive oxygen and nitrogen species, and various proteolytic enzymes, events that may exacerbate neuronal damage rather than incite outgrowth or repair mechanisms. Microglia do not appear to function as true antigen-presenting cells. However, there is circumstantial evidence that suggests functional heterogeneity within Microglia. Pharmacological agents that suppress Microglial activation or reduce Microglial-mediated oxidative damage may prove useful strategies to slow the progression of Alzheimer's disease

  304. Kingham PJ, Cuzner ML, Pocock JM (1999) Apoptotic pathways mobilized in Microglia and neurones as a consequence of chromogranin A-induced Microglial activation. J.Neurochem. 73:538-547
    Abstract: Senile plaques of Alzheimer's brain are characterized by activated Microglia and immunoreactivity for the peptide chromogranin A. We have investigated the mechanisms by which chromogranin A activates Microglia, producing modulators of neuronal survival. Primary cultures of rat brain-derived Microglia display a reactive phenotype within 24 h of exposure to 10 nM chromogranin A, culminating in Microglial death via apoptotic mechanisms mediated by interleukin-1beta converting enzyme. The signalling cascade initiated by chromogranin A triggers nitric oxide production followed by enhanced Microglial glutamate release, inhibition of which prevents Microglial death. The plasma membrane carrier inhibitor aminoadipate and the type II/III metabotropic glutamate receptor antagonist (RS)-alpha-methyl-4-sulphonophenylglycine are equally protective. A significant amount of the released glutamate occurs from bafilomycin-sensitive stores, suggesting a vesicular mode of release. Inhibition of this component of release affords significant Microglial protection. Conditioned medium from activated Microglia kills cerebellar granule cells by inducing caspase-3-dependent neuronal apoptosis. Brain-derived neurotrophic factor is partially neuroprotective, as are ionotropic glutamate receptor antagonists, and, when combined with boiling of conditioned medium, full protection is achieved; nitric oxide synthase inhibitors are ineffective

  305. Kurt MA, Davies DC, Kidd M (1999) beta-Amyloid immunoreactivity in astrocytes in Alzheimer's disease brain biopsies: an electron microscope study. Exp.Neurol. 158:221-228
    Abstract: The deposition of amyloid beta (A beta) protein plays a central role in the neuropathology of Alzheimer's disease (AD) and it constitutes the core of classical senile plaques. However, little is known about its intracellular distribution. An immunogold electron microscope study was therefore carried out on biopsies of brain tissue from patients with AD using a monoclonal antibody raised against residues 8 to 17 of the A beta protein. Specific A beta immunogold labeling was observed over extracellular amyloid fibrils associated with senile plaques. In addition, widespread intracellular A beta immunolabeling was observed adjacent to granular structures (30-40 nm in diameter) within membrane-bound processes. Pretreatment of some sections with amylase or omission of lead citrate staining from others strongly suggests that the electron-dense granular structures associated with A beta immunoreactivity are glycogen. Some of the A beta-immunolabeled processes contained gliofilaments and immunolabeling of alternate sections for glial fibrillary acidic protein confirmed that the A beta-immunolabeled processes were astrocytic. A beta immunolabeling was not observed over neuronal or Microglial processes. Whether the presence of A beta protein in astrocytes is the result of synthetic or degradation processes requires further investigation

  306. Lemke MR, Glatzel M, Henneberg AE (1999) AntiMicroglia antibodies in sera of Alzheimer's disease patients. Biol.Psychiatry 45:508-511
    Abstract: BACKGROUND: Immune mechanisms seem to contribute to the degenerative process in Alzheimer's disease. Antibodies directed against animal brain tissue were found in sera of Alzheimer's patients. METHODS: Antibodies were measured in sera of 25 Alzheimer's patients and a comparison group of 25 age- and sex-matched controls. Sera were tested for their immunological response to various brain structures of postmortem human brain tissue. RESULTS: In 8 patients with Alzheimer's disease perinuclear antibodies directed against Microglia were found in amygdala and frontal cortex. In the control group 1 subject showed antibody binding to Microglia. CONCLUSIONS: Perinuclear antibodies to Microglia may play a role in tissue destruction of Alzheimer's disease. These data add to the evidence that immune mechanisms play a role in the pathophysiology of Alzheimer's disease

  307. Lewandowska E, Bertrand E, Kulczycki J, Lipczynska-Lojkowska W, Lechowicz W, Stankiewicz J (1999) Microglia and neuritic plaques in familial Alzheimer's disease induced by a new mutation of presenilin-1 gene. An ultrastructural study. Folia Neuropathol. 37:243-246
    Abstract: The results of the ultrastructural study of the brains of two sisters with familial Alzheimer's disease (AD) induced by a new mutation of presenilin-1 (PS-1) gene who died at the young age (35 and 37 years) are presented. In both cases, the changes typical of AD with particularly large number of neuritic plaques (NPs) were found. Microglial cells were located between amyloid core and neurites. At the ultrastructural level, the content of Microglial cytoplasm was differentiated (amyloid fibrils or/and phagocytic bodies). This may suggest that Microglial cells participate in forming of amyloid fibrils and/or phagocytosis of amyloid

  308. Lipsky PE (1999) The clinical potential of cyclooxygenase-2-specific inhibitors. Am.J.Med. 106:51S-57S
    Abstract: Emerging evidence suggests that cyclooxygenase-2 (COX-2) has diverse physiologic and pathophysiologic functions. It is expressed constitutively in the developing kidney and brain, playing a role in their proper maturation and function. Further, COX-2 expression may be up-regulated at certain sites: in the kidney during sodium restriction; in the Microglia of cognitive centers within the hippocampus and cortex in Alzheimer's disease; and in intestinal adenomas and colon tumors. On the basis of COX-2 expression in Alzheimer's disease and colon cancer, COX-2-specific inhibitors may find clinical utility in the prevention or treatment of these conditions. Despite this apparently optimistic outlook for future uses of COX-2 inhibitors, most of the findings supporting this perspective are based on in vitro and in vivo models and must be rigorously corroborated in human studies, some of which are already planned

  309. Love S, Barber R, Wilcock GK (1999) Increased poly(ADP-ribosyl)ation of nuclear proteins in Alzheimer's disease. Brain 122 ( Pt 2):247-253
    Abstract: Experimental studies indicate that overactivation of the DNA repair protein poly(ADP-ribose) polymerase (PARP) in response to oxidative damage to DNA can cause cell death due to depletion of NAD+. Oxidative damage to DNA and other macromolecules has been reported to be increased in the brains of patients with Alzheimer's disease. In the present study we sought evidence of PARP activation in Alzheimer's disease by immunostaining sections of frontal and temporal lobe from autopsy material of 20 patients and 10 controls, both for PARP itself and for its end-product, poly(ADP-ribose). All of the brains had previously been subjected to detailed neuropathological examination to confirm the diagnosis of Alzheimer's disease or, in the controls, to exclude Alzheimer's disease-type pathology. Double immunolabelling for poly(ADP-ribose) and microtubule-associated protein 2 (MAP2), glial fibrillary-acidic protein (GFAP), CD68, A beta-protein or tau was used to assess the identity of the cells with poly(ADP-ribose) accumulation and their relationship to plaques and neurofibrillary tangles. Both

  310. Marx F, Blasko I, Grubeck-Loebenstein B (1999) Mechanisms of immune regulation in Alzheimer's disease: a viewpoint. Arch.Immunol.Ther.Exp.(Warsz.) 47:205-209
    Abstract: The immune system may play an important role in the neurodegenerative process in Alzheimer's disease (AD). Complement components, eicosanoids and cytokines are found in cerebral amyloid plaques. These inflammatory proteins may stimulate the amyloid beta (Abeta) production, support its aggregation and increase its cytotoxicity, thus aggrevating the pathology of AD. Abeta may trigger their release from activated Microglia and astrocytes which are the main sources of these proteins. However, there are also indications for a protective role of the immune system against the development of AD. Microglial cells have been shown to degrade Abeta and recent evidence suggests a role of autoreactive Abeta-specific T cells in the elimination of the peptide. This mechanism seems to be impaired in the majority of patients with AD. An Abeta-specific immune reaction may thus represent a natural defence mechanism directed against the accumulation of dangerous amyloidogenic substances. Impairment of the immune system and the failure to eliminate a toxic metabolite can be the basis for a chronic non-specific inflammatory process in the brain, as described above. AD is a good example how an immune response may lead to tissue destruction and neuronal loss instead of maintaining the integrity of the body

  311. McCarron MO, Nicoll JA, Stewart J, Ironside JW, Mann DM, Love S, Graham DI, Dewar D (1999) The apolipoprotein E epsilon2 allele and the pathological features in cerebral amyloid angiopathy-related hemorrhage. J.Neuropathol.Exp.Neurol. 58:711-718
    Abstract: Cerebral amyloid angiopathy (CAA) is associated with apolipoprotein E (APOE gene, apoE protein) polymorphism: current evidence suggests that the epsilon4 allele is a risk factor for the development of CAA and the epsilon2 allele predisposes to hemorrhage. We sought to determine the relationship between the APOE epsilon2 allele and both the immunoreactivity profiles and vascular complications of CAA. We performed immunohistochemistry for amyloid beta-protein (A beta), apoE, cystatin C, and activated Microglia, and examined the morphology of cortical and leptomeningeal vessels in 37 CAA-related hemorrhage (CAAH), 26 Alzheimer disease (AD) patients, and 20 controls. The extent of immunostaining of vessels for A beta, apoE, cystatin C, and perivascular activated Microglia increased from controls through AD to a maximum in CAAH patients. Among cases with CAA (37 CAAH, 19 AD, and 6 controls, n = 62) vascular apoE (p < 5 x 10(-4)), cystatin C (p < 10(-4)), activated Microglia (p < 10(-4)), vessels with a high ratio of wall thickness to lumen diameter (p < 0.003) as well as dilated/microaneurysmal vessels (p < 0.01) were present more frequently in patients with hemorrhage than without; however, these features were not associated with the APOE epsilon2 allele. Fibrinoid necrosis alone was associated with the APOE epsilon2 allele (p < 0.04) and we suggest that over-representation of APOE epsilon2 in CAAH may result from its association with fibrinoid necrosis

  312. McGeer EG, McGeer PL (1999) Brain inflammation in Alzheimer disease and the therapeutic implications. Curr.Pharm.Des 5:821-836
    Abstract: Immunohistochemical studies suggested the existence of a chronic inflammatory condition in affected regions of the brain in Alzheimer disease (AD). Since inflammation can be damaging to host tissue, it was hypothesized that antiinflammatory drugs might inhibit both the onset and the progression of AD. This hypothesis is supported by a number of epidemiological studies suggesting that the prevalence of AD in persons is reduced by 40 - 50% in persons using antiinflammatory drugs. In one small pilot trial in early AD, the nonsteroidal antiinflammatory drug indomethacin appeared to halt the progressive memory loss. Immunohistochemical and molecular biological studies on immune system components in AD brain are revealing the complexities of the innate immune reaction. This very complexity may offer points of therapeutic intervention for new types of antiinflammatory agents. The complement system, Microglia and cytokines are key components. This review summarizes the present state of knowledge on the immune system elements found in AD brain

  313. McGeer PL, McGeer EG (1999) Inflammation of the brain in Alzheimer's disease: implications for therapy. J.Leukoc.Biol. 65:409-415
    Abstract: We briefly describe the similarities and differences between a systemic and a local immune reaction and review the evidence that the latter occurs in Alzheimer's disease (AD) brains. The evidence comes mainly from studies on the complement system, Microglia, and cytokines, all of which are important actors in the inflammatory process. The evidence is now overwhelming that the complement proteins and many of the mediators of inflammation are produced locally by brain cells. We will mention briefly the many epidemiological studies indicating that the use of anti-inflammatory drugs reduces the incidence and slows the progress of AD. Mention will also be made of some recent work on animal models of possible relevance to AD and inflammation

  314. Meda L, Baron P, Prat E, Scarpini E, Scarlato G, Cassatella MA, Rossi F (1999) Proinflammatory profile of cytokine production by human monocytes and murine Microglia stimulated with beta-amyloid[25-35]. J.Neuroimmunol. 93:45-52
    Abstract: Growing evidence indicates that amyloid (A beta) deposition and phagocyte activation participate in inflammatory reactions in the brain during the course of Alzheimer's disease. To further investigate the effects of A beta-phagocyte interaction, we examined the production of proinflammatory (IL-1beta, IL-6), chemotactic (MIP-1alpha, IP-10) and inhibitory (IL-1Ra, IL-10 and TGFbeta1) cytokines by cultured human monocytes and mouse Microglial cells upon stimulation with A beta[25-35]. Northern blot analysis and specific immunoassays demonstrated that A beta[25-35] triggers mRNA expression and release of IL-1beta, IL-1Ra and MIP-1alpha but not of IL-6, IL-10, TGFbeta1 and IP-10 from human monocytes. Similar results were obtained by examining the production of IL-1beta, IL-6 and IL-10 from mouse Microglial cells in the same experimental conditions. Taken together, these data indicate that A beta-phagocyte interaction can drive a different response towards cytokine production by monocytes and Microglia, with a particular proinflammatory trend, and further support a role for A beta deposition as a triggering factor of inflammatory events in Alzheimer's disease

  315. Morelli L, Prat MI, Castano EM (1999) Differential accumulation of soluble amyloid beta peptides 1-40 and 1-42 in human monocytic and neuroblastoma cell lines. Implications for cerebral amyloidogenesis. Cell Tissue Res. 298:225-232
    Abstract: Alzheimer's disease (AD) is characterized by the massive deposition in the brain of the 40-42-residue amyloid beta protein (A(beta)). While A(beta)1-40 predominates in the vascular system, A(beta)1-42 is the major component of the senile plaques in the neuropil. The concentration of both A(beta) species required to form amyloid fibrils in vitro is micromolar, yet soluble A(betas) found in normal and AD brains are in the low nanomolar range. It has been recently proposed that the levels of A(beta) sufficient to trigger amyloidogenesis may be reached intracellularly. To study the internalization and intracellular accumulation of the major isoforms of A(beta), we used THP-1 and IMR-32 neuroblastoma cells as models of human monocytic and/or macrophagic and neuronal lineages, respectively. We tested whether these cells were able to internalize and accumulate 125I-A(beta)1-40 and 125I-A(beta)1-42 differentially when offered at nanomolar concentrations and free of large aggregates, conditions that mimic a prefibrillar stage of A(beta) in AD brain. Our results showed that THP-1 monocytic cells internalized at least 10 times more 125I-A(betas) than IMR-32 neuroblastoma cells, either isolated or in a coculture system. Moreover, 125I-A(beta)1-42 presented a higher adsorption, internalization, and accumulation of undigested peptide inside cells, as opposed to 125I-A(beta)1-40. These results support that A(beta)1-42, the major pathogenic form in AD, may reach supersaturation and generate competent nuclei for amyloid fibril formation intracellularly. In light of the recently reported strong neurotoxicity of soluble, nonfibrillar A(beta)1-42, we propose that intracellular amyloidogenesis in Microglia is a protective mechanism that may delay neurodegeneration at early stages of the disease

  316. Paris D, Town T, Parker TA, Tan J, Humphrey J, Crawford F, Mullan M (1999) Inhibition of Alzheimer's beta-amyloid induced vasoactivity and proinflammatory response in Microglia by a cGMP-dependent mechanism. Exp.Neurol. 157:211-221
    Abstract: beta-amyloid (Abeta) peptides are the major protein components of senile plaques in Alzheimer's disease (AD) brains. Vascular damage and reactive gliosis are found colocalized with amyloid deposits in AD brains, suggesting that the vasculature may be a clinically significant site of AD pathology. Our results show that freshly solubilized Abeta1-40 enhances the vasoconstriction induced by endothelin-1 (ET-1) and increases resistance to relaxation triggered by nitric oxide (NO), suggesting that Abeta may oppose the NO/cGMP pathway. Using specific inhibitors and activators of the NO/cGMP pathway, we show that Abeta vasoactivity is not due to a modulation of nitric oxide synthase (NOS) or soluble guanylyl cyclase (sGC). However, we find that a selective cGMP phosphodiesterase (cGMP-PDE) inhibitor (dipyridamole) is able to interactively block the enhanced vasoconstriction as well as the opposition to relaxation induced by Abeta, suggesting that Abeta could effect the activity of this enzyme. Cyclic GMP levels, but not cAMP concentrations, are reduced after Abeta treatment of rat aortic rings, further substantiating this hypothesis. Moreover, in examination of this pathway in another cell type pertinent to AD, we find that Abeta induces a proinflammatory response in Microglia as evidenced by increased leukotriene B4 release. We show that both dipyridamole and compounds which increase cGMP levels prevent Abeta-induced Microglial inflammation. Our results suggest that therapeutic intervention aimed at reduction of Microglial-mediated inflammation via inhibition of cGMP-PDE or elevation of cGMP may be beneficial in the treatment of AD

  317. Renkawek K, Stege GJ, Bosman GJ (1999) Dementia, gliosis and expression of the small heat shock proteins hsp27 and alpha B-crystallin in Parkinson's disease. Neuroreport 10:2273-2276
    Abstract: Cognitive impairment and dementia are common in the later stages of Parkinson's disease (PD). Neuropathological examination of demented PD (PDD) patients often reveals changes that are typical of Alzheimer's disease (AD). In AD, there is a massive reactive gliosis and increased expression of the small heat shock proteins (hsp) hsp27 and alpha B-crystallin. Since these proteins are characteristic for reactive astrocytes in AD, we investigated their expression in the brains of PDD patients. The results were compared with those obtained in the brains of non-demented PD patients. We found (1) no detectable expression of hsp in PD without dementia, and low expression in PD with mild dementia; (2) reactive gliosis and increased expression of hsp in the cortex of PDD brains; (3) a strong association between hsp immunoreactivity and the severity of the AD-specific changes, especially with the number of tangles in the hippocampus; (4) a distinct immunoreaction of alpha B-crystallin in Microglia in the substantia nigra and in the hippocampus in PDD. These results indicate that astrocytes react to the disease conditions in AD and in PDD in a similar way, namely by the increased expression of small heat shock proteins, and present additional evidence for the thesis that the pathology of the dementia in PD is related to that in AD

  318. Reynolds WF, Rhees J, Maciejewski D, Paladino T, Sieburg H, Maki RA, Masliah E (1999) Myeloperoxidase polymorphism is associated with gender specific risk for Alzheimer's disease. Exp.Neurol. 155:31-41
    Abstract: Myeloperoxidase (MPO) is a myeloid-specific enzyme that generates hypochlorous acid and other reactive oxygen species. MPO is present at high levels in circulating neutrophils and monocytes but is not detectable in Microglia, brain-specific macrophages, in normal brain tissue. However, an earlier study indicated that MPO is present in macrophage-Microglia at multiple sclerosis lesions, suggesting that reactivation of MPO gene expression may play a role in neurodegenerative diseases involving macrophage-Microglia. In the present study, MPO is shown to colocalize with amyloid beta (Abeta) in senile plaques in cerebral cortex sections from Alzheimer's disease (AD) brain tissue. Microglia costaining for MPO and CD68 are closely associated with plaques, suggesting that plaque components induce MPO expression in Microglia. In support of this interpretation, treatment of rodent Microglia with aggregated Abeta(1-42) was shown to induce MPO mRNA expression. Also, the ApoE4 allele, the major AD risk factor associated with increased Abeta deposition, was shown to correlate with increased MPO deposition in plaques (P = 0.01, ANOVA). Finally, a genetic polymorphism links MPO expression to Alzheimer's risk, in that a higher expressing SpSp MPO genotype was associated with increased incidence of AD in females, and decreased incidence in males (P = 0.006). These findings suggest that the MPO polymorphism is a gender-specific risk factor for Alzheimer's disease

  319. Rogers JT, Leiter LM, McPhee J, Cahill CM, Zhan SS, Potter H, Nilsson LN (1999) Translation of the Alzheimer amyloid precursor protein mRNA is up-regulated by interleukin-1 through 5'-untranslated region sequences. J.Biol.Chem. 274:6421-6431
    Abstract: The amyloid precursor protein (APP) has been associated with Alzheimer's disease (AD) because APP is processed into the beta-peptide that accumulates in amyloid plaques, and APP gene mutations can cause early onset AD. Inflammation is also associated with AD as exemplified by increased expression of interleukin-1 (IL-1) in Microglia in affected areas of the AD brain. Here we demonstrate that IL-1alpha and IL-1beta increase APP synthesis by up to 6-fold in primary human astrocytes and by 15-fold in human astrocytoma cells without changing the steady-state levels of APP mRNA. A 90-nucleotide sequence in the APP gene 5'-untranslated region (5'-UTR) conferred translational regulation by IL-1alpha and IL-1beta to a chloramphenicol acetyltransferase (CAT) reporter gene. Steady-state levels of transfected APP(5'-UTR)/CAT mRNAs were unchanged, whereas both base-line and IL-1-dependent CAT protein synthesis were increased. This APP mRNA translational enhancer maps from +55 to +144 nucleotides from the 5'-cap site and is homologous to related translational control elements in the 5'-UTR of the light and and heavy ferritin genes. Enhanced translation of APP mRNA provides a mechanism by which IL-1 influences the pathogenesis of AD

  320. Soontornniyomkij V, Wang G, Pittman CA, Hamilton RL, Wiley CA, Achim CL (1999) Absence of brain-derived neurotrophic factor and trkB receptor immunoreactivity in glia of Alzheimer's disease. Acta Neuropathol.(Berl) 98:345-348
    Abstract: Alterations in the neuronal expression of some neurotrophins have been shown in various neurodegenerative processes, particularly Alzheimer's disease (AD). Glia may up-regulate neurotrophins and their high-affinity tyrosine kinase (trk) receptors in response to neural injury. In human immunodeficiency virus type 1 (HIV-1) encephalitis, activated Microglia were shown to express brain-derived neurotrophic factor (BDNF), while reactive astrocytes expressed trkB receptor. This observation has suggested the existence of local neurotrophic regulation between different glial populations. To characterize the glial cellular distribution of BDNF and trkB receptor proteins in AD, we studied selected regions of postmortem brains from four AD and three age-matched control patients by double-immunofluorescence confocal microscopy. In both groups, BDNF immunoreactivity was distributed in neuronal perikarya and neuritic processes in the neocortex and hippocampus. No BDNF immunoreactivity was observed in Microglia or astrocytes within and between senile plaques of AD. Catalytic trkB receptor immunoreactivity was present in neuronal perikarya in the neocortex and hippocampus. Reactive astrocytes and Microglia were not immunoreactive for catalytic trkB. The absence of BDNF and trkB proteins in glia in AD patients is in contrast to the finding in patients with HIV-1 encephalitis. This difference suggests that glial expression of BDNF and trkB proteins may be characteristic of particular disease processes, rather than merely representing a stereotyped response to any type of neural injury

  321. Stege GJ, Bosman GJ (1999) The biochemistry of Alzheimer's disease. Drugs Aging 14:437-446
    Abstract: In the course of the biochemical efforts devoted to elucidation of the cause(s) and mechanism(s) of neurodegeneration in Alzheimer's disease (AD), much attention has been given to the processes by which amyloid is generated from amyloid precursor protein, notwithstanding the finding that mutations in 2 other proteins, presenilin 1 and 2, are associated with early-onset, familial AD in the majority of patients. In addition, the reason why the apolipoprotein E epsilon4 allele is over-represented in patients with the sporadic form of AD is unknown. Furthermore, the degree of dementia is clearly associated more with the degree of neurofibrillary pathology than with the amyloid plaque burden. In general, amyloid formation may very well be at the end of a pathophysiological cascade, set in motion by many different triggers. This cascade could involve excessive apoptosis, followed by necrosis and inflammation. In this process, Microglia as well as astrocytes are involved. Disturbance of I or more critical signal transduction processes, especially at the level of the plasma membrane, may be an important trigger. The pathogenesis of AD is complicated, but further identification of the processes of neurodegeneration will also lead to identification of the factors that make specific neurons vulnerable and, hopefully, point the way to a means to prevent neuronal degeneration at an early stage

  322. Stephenson D, Rash K, Smalstig B, Roberts E, Johnstone E, Sharp J, Panetta J, Little S, Kramer R, Clemens J (1999) Cytosolic phospholipase A2 is induced in reactive glia following different forms of neurodegeneration. Glia 27:110-128
    Abstract: Many recent studies have emphasized the deleterious role of inflammation in CNS injury. Increases in free fatty acids, eicosanoids, and products of lipid peroxidation are known to occur in various conditions of acute and chronic CNS injury, including cerebral ischemia, traumatic brain injury, and Alzheimer's disease. Although an inflammatory response can be induced by many different means, phospholipases, such as cytosolic phospholipase A(2) (cPLA(2)), may play an important role in the production of inflammatory mediators and in the production of other potential second messengers. cPLA(2) hydrolyzes membrane phospholipids and its activity liberates free fatty acids leading directly to the production of eicosanoids. We investigated the cellular localization of cytosolic phospholipase A(2) in the CNS following: (1) focal and global cerebral ischemia, (2) facial nerve axotomy, (3) human cases of Alzheimer's disease, (4) transgenic mice overexpressing mutant superoxide dismutase, a mouse model of amyotrophic lateral sclerosis, and (5) transgenic mice overexpressing mutant amyloid precursor protein, which exhibits age-related amyloid deposition characteristic of Alzheimer's disease. We show that in every condition evaluated, cytosolic phospholipase A(2) is present in reactive glial cells within the precise region of neuron loss. In conditions where neurons did not degenerate or are protected from death, cytosolic phospholipase A(2) is not observed. Both astrocytes and Microglial cells are immunoreactive for cytosolic phospholipase A(2) following injury, with astrocytes being the most consistent cell type expressing cytosolic phospholipase A(2). The presence of cytosolic phospholipase A(2) does not merely overlap with reactive astroglia, as reactive astrocytes were observed that did not exhibit cytosolic phospholipase A(2) immunoreactivity. In most conditions evaluated, inflammatory processes have been postulated to play a pivotal role and may even participate in neuronal cell death. These results suggest that cytosolic phospholipase A(2) may prove an attractive therapeutic target for neurodegeneration

  323. Tan J, Town T, Paris D, Mori T, Suo Z, Crawford F, Mattson MP, Flavell RA, Mullan M (1999) Microglial activation resulting from CD40-CD40L interaction after beta-amyloid stimulation. Science 286:2352-2355
    Abstract: Alzheimer's disease (AD) has a substantial inflammatory component, and activated Microglia may play a central role in neuronal degeneration. CD40 expression was increased on cultured Microglia treated with freshly solublized amyloid-beta (Abeta, 500 nanomolar) and on Microglia from a transgenic murine model of AD (Tg APPsw). Increased tumor necrosis factor alpha production and induction of neuronal injury occurred when Abeta-stimulated Microglia were treated with CD40 ligand (CD40L). Microglia from Tg APPsw mice deficient for CD40L demonstrated reduction in activation, suggesting that the CD40-CD40L interaction is necessary for Abeta-induced Microglial activation. Finally, abnormal tau phosphorylation was reduced in Tg APPsw animals deficient for CD40L, suggesting that the CD40-CD40L interaction is an early event in AD pathogenesis

  324. Torreilles F, Salman-Tabcheh S, Guerin M, Torreilles J (1999) Neurodegenerative disorders: the role of peroxynitrite. Brain Res.Brain Res.Rev. 30:153-163
    Abstract: Inflammatory reaction is thought to be an important contributor to neuronal damage in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS) and the parkinsonism dementia complex of Guam. Among the toxic agents released in brain tissues by activated cells, we focus attention in this review on peroxynitrite, the product of the reaction between nitric oxide (NO) and superoxide. Peroxynitrite is a strong oxidizing and nitrating agent which can react with all classes of biomolecules. In the CNS it can be generated by Microglial cells activated by pro-inflammatory cytokines or beta-amyloid peptide (beta-A) and by neurons in three different situations: hyperactivity of glutamate neurotransmission, mitochondrial dysfunction and depletion of L-arginine or tetrahydrobiopterin. The first two situations correspond to cellular responses to an initial neuronal injury and the peroxynitrite formed only exacerbates the inflammatory process, whereas in the third situation the peroxynitrite generated directly contributes to the initiation of the neurodegenerative process

  325. van Muiswinkel FL, Raupp SF, de Vos NM, Smits HA, Verhoef J, Eikelenboom P, Nottet HS (1999) The amino-terminus of the amyloid-beta protein is critical for the cellular binding and consequent activation of the respiratory burst of human macrophages. J.Neuroimmunol. 96:121-130
    Abstract: Here, we show that amyloid-beta (Abeta) is capable to prime and activate the respiratory burst of human macrophages. Previously, the N-terminus of Abeta(1-42) has been shown to contain a cell binding domain that is implicated in eliciting neuropathogenic Microglia in vitro. To evaluate the role of this domain in the Abeta(1-42)-induced respiratory burst activity, the effect of Abeta subfragments on the Abeta(1-42)-induced superoxide release were studied. On the basis of the antagonistic properties of Abeta(1-16), it is concluded that the N-terminal region of Abeta is critical for the cellular binding and consequent activation of the respiratory burst of human phagocytes

  326. Veerhuis R, Janssen I, De Groot CJ, van Muiswinkel FL, Hack CE, Eikelenboom P (1999) Cytokines associated with amyloid plaques in Alzheimer's disease brain stimulate human glial and neuronal cell cultures to secrete early complement proteins, but not C1-inhibitor. Exp.Neurol. 160:289-299
    Abstract: Complement activation products C1q, C4c/d, and C3c/d in amyloid plaques in Alzheimer's disease probably result from direct binding and activation of C1 by amyloid beta peptides. RT-PCR and in situ hybridization studies have shown that several complement factors are produced in the brain parenchyma. In the present study, cytokines that can be detected in amyloid plaques (i.e., interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-alpha) were found to differentially stimulate the expression of C1 subcomponents, C1-Inhibitor (C1-Inh), C4, and C3, by astrocyte and Microglial cell cultures derived from postmortem adult, human brain specimens and by neuroblastoma cell lines in culture. C1r and C1s were secreted at low levels by astrocytes and neuroblastoma cell lines. Exposure of cells to IL-1 alpha, IL-1 beta, TNF-alpha and to a far lesser extent IL-6, markedly upregulated C1r, C1s, and C3 production. C4 synthesis increased in response to interferon (IFN)-gamma and IL-6, whereas that of C1-Inh could be stimulated only by IFN-gamma. Thus, C1-Inh production is refractory to stimulation by plaque-associated cytokines, whereas these cytokines do stimulate C1r, C1s, and also C4 and C3 secretion by astrocytes and neuronal cells in culture. In contrast to the amyloid plaque associated cytokines IL-1 beta, IL-1 alpha, and TNF-alpha, the amyloid peptide A beta 1-42 itself did not stimulate C1r and C1s synthesis by astrocytes, Microglial cells, or neuroblastoma cell lines. Microglial cells were the only cell type that constitutively expressed C1q. The ability of C1q to reassociate with newly formed C1r and C1s upon activation of C1 and subsequent inactivation by C1-Inh, may enable ongoing complement activation at sites of amyloid deposition, especially when C1-Inh is consumed and not replaced

  327. Xia MQ, Hyman BT (1999) Chemokines/chemokine receptors in the central nervous system and Alzheimer's disease. J.Neurovirol. 5:32-41
    Abstract: Alzheimer's disease (AD) is the most common cause of dementia in the elderly, and the fourth leading cause of death in the United States. Its pathological changes include amyloid beta deposits, neurofibrillary tangles and a variety of 'inflammatory' phenomenon such as activation of Microglia and astrocytes. The pathological significance of inflammatory responses elicited by resident central nervous system (CNS) cells has drawn considerable attention in recent years. Chemokines belongs to a rapidly expanding family of cytokines, the primary function of which is control of the correct positioning of cells in tissues and recruitment of leukocytes to the site of inflammation. Study of this very important class of inflammatory cytokines may greatly help our understanding of inflammation in the progress of AD, as well as other neurodegenerative diseases. So far, immunoreactivity for a number of chemokines (including IL-8, IP-10, MIP-1beta, MIPalpha and MCP-1) and chemokine receptors (including CXCR2, CXCR3, CXCR4, CCR3, CCR5 and Duffy antigen) have been demonstrated in resident cells of the CNS, and upregulation of some of the chemokines and receptors are found associated with AD pathological changes. In this review, we summarize findings regarding the expression of chemokines and their receptors by CNS cells under physiological and pathological conditions. Although little is known about the potential pathophysiological roles of chemokines in CNS, we have put forward hypotheses on how chemokines may be involved in AD

  328. Yamada T, Tsujioka Y, Taguchi J, Takahashi M, Tsuboi Y, Moroo I, Yang J, Jefferies WA (1999) Melanotransferrin is produced by senile plaque-associated reactive Microglia in Alzheimer's disease. Brain Res. 845:1-5
    Abstract: Melanotransferrin (MTf), also known as p97, has been localized in capillary endothelial cells of human brain. In Alzheimer's-diseased (AD) brain tissues, reactive Microglial cells located in senile plaques exhibit elevated levels of MTf. The localization of the p97 protein may reflect its site of synthesis or could reflect a paracrine site of action. We examined the expression of MTf mRNA by in situ hybridization histochemistry using AD and healthy brain tissues. We also examined normal liver tissues by immunohistochemistry and in situ hybridization. In all the brain tissues examined, capillaries had positive signals for MTf mRNA. In AD tissues, expression of MTf mRNA appeared in reactive Microglial cells in the grey matter specifically associated with dense plaques. In liver tissues, immunohistochemistry using anti-p97 antibody demonstrated that sinusoids were positively stained. In addition, in situ hybridization histochemistry revealed that hepatocytes had positive signals. These results suggest that p97 expression in reactive Microglial cells are closely related to AD pathology. These results also support the notion that p97, which appears elevated in the cerebral spinal fluid and serum of AD patients, originates in the reactive Microglia associated with dense senile plaques. Thus, p97 is a unique cellular hallmark of AD and further suggests that metal transport mechanisms play a role in this disease

  329. Yermakova AV, Rollins J, Callahan LM, Rogers J, O'Banion MK (1999) Cyclooxygenase-1 in human Alzheimer and control brain: quantitative analysis of expression by Microglia and CA3 hippocampal neurons. J.Neuropathol.Exp.Neurol. 58:1135-1146
    Abstract: Epidemiological and clinical studies suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) that inhibit cyclooxygenase (COX) slow the progression and delay the onset of Alzheimer disease (AD). Two isoforms of cyclooxygenase have been identified. Although much effort has recently been focused on the inducible COX-2 isoform, little is known about COX-1 expression in human brain. We report that COX-1 message and immunoreactivity are localized to human hippocampal CA3 and CA4 neurons, granular neurons in neocortical layer IV, and occasional cortical pyramidal neurons. Quantitative in situ hybridization showed no differences between COX-1 mRNA levels in control and AD CA3 hippocampal neurons. COX-1 immunoreactivity was also present in Microglial cells in gray and white matter in all brain regions examined. COX-1 appeared to be expressed in Microglial cells regardless of their activation state as determined by HLA-DR immunostaining. However, COX-1 immunopositive Microglia were found in association with Abeta plaques, and the density of COX-1 immunopositive Microglia in AD fusiform cortex was increased. This pattern suggests an overall increase of COX-1 expression in AD. Currently used NSAIDs inhibit both isoforms of cyclooxygenase. The present study shows that COX-1 is widely expressed in human brain, and raises the possibility that COX-1 may contribute to CNS pathology

  330. Aisen PS, Pasinetti GM (1998) Glucocorticoids in Alzheimer's disease. The story so far. Drugs Aging 12:1-6
    Abstract: The inflammatory hypothesis of Alzheimer's disease states that specific inflammatory mechanisms, including the cytokine-driven acute-phase response, complement activation and Microglial activation, contribute to neurodegeneration. If the hypothesis is correct, anti-inflammatory treatment aimed at suppression of these mechanisms could slow the rate of disease progression. Towards this goal, a multicentre trial of prednisone in Alzheimer's disease is under way and pilot studies of other anti-inflammatory regimens are being conducted

  331. Akama KT, Albanese C, Pestell RG, Van Eldik LJ (1998) Amyloid beta-peptide stimulates nitric oxide production in astrocytes through an NFkappaB-dependent mechanism. Proc.Natl.Acad.Sci.U.S.A 95:5795-5800
    Abstract: The major pathological features of Alzheimer's disease (AD) include amyloid plaques composed primarily of the beta-amyloid (Abeta) peptide, degenerating neurons and neurofibrillary tangles, and the presence of numerous activated astrocytes and Microglia. Although extensive genetic data implicate Abeta in the neurodegenerative cascade of AD, the molecular mechanisms underlying its effects on neurons and glia and the relationship between glial activation and neuronal death are not well defined. Abeta has been shown to induce glial activation, and a growing body of evidence suggests that activated glia contribute to neurotoxicity through generation of inflammatory cytokines and neurotoxic free radicals, such as nitric oxide (NO), potent sources of oxidative stress known to occur in AD. It is therefore crucial to identify specific Abeta-induced molecular pathways mediating these responses in activated glia. We report that Abeta stimulates the activation of the transcription factor NFkappaB in rat astrocytes, that NFkappaB activation occurs selectively from p65 transactivation domain 2, and that Abeta-induced NO synthase expression and NO production occur through an NFkappaB-dependent mechanism. This demonstration of how Abeta couples an intracellular signal transduction pathway involving NFkappaB to a potentially neurotoxic response provides a key mechanistic link between Abeta and the generation of oxidative damage. Our results also suggest possible molecular targets upon which to focus future drug discovery efforts for AD

  332. Arnold SE, Trojanowski JQ, Gur RE, Blackwell P, Han LY, Choi C (1998) Absence of neurodegeneration and neural injury in the cerebral cortex in a sample of elderly patients with schizophrenia. Arch.Gen.Psychiatry 55:225-232
    Abstract: BACKGROUND: The cognitive and functional deterioration that is observed in many "poor-outcome" patients with schizophrenia suggests a neurodegenerative process extending into late life. Previous diagnostic studies have excluded known neurodegenerative diseases as explanations for this dementia. However, we hypothesized that relatively small accumulations of age- or disease-related neurodegenerative lesions occurring in an otherwise abnormal brain could result in deterioration in schizophrenia. METHODS: Postmortem studies were conducted using 23 prospectively accrued elderly persons with chronic schizophrenia for whom clinical ratings had been determined before death, 14 elderly control patients with no neuropsychiatric disease, and 10 control patients with Alzheimer disease. Immunohistochemistry and unbiased stereological counting methods were used to quantify common neurodegenerative lesions (ie, neurofibrillary tangles, amyloid plaques, and Lewy bodies) and cellular reactions to a variety of noxious stimuli (ubiquitinated dystrophic neurites, astrocytosis, and Microglial infiltrates) in the ventromedial temporal lobe and the frontal and the calcarine (primary visual) cortices. RESULTS: No statistically significant differences were found between the patients with schizophrenia and the control patients without neuropsychiatric disease for the densities of any of the markers, while both groups exhibited fewer lesions than did the control group with Alzheimer disease. Correlation analyses in the schizophrenia sample failed to identify significant correlations between cognitive and psychiatric ratings and densities of any of the neuropathologic markers. CONCLUSIONS: No significant evidence of neurodegeneration or ongoing neural injury in the cerebral cortex was found in this sample of elderly persons with schizophrenia. Furthermore, the behavioral and cognitive deterioration observed in late life did not correlate with age-related degenerative phenomena

  333. Balin BJ, Gerard HC, Arking EJ, Appelt DM, Branigan PJ, Abrams JT, Whittum-Hudson JA, Hudson AP (1998) Identification and localization of Chlamydia pneumoniae in the Alzheimer's brain. Med.Microbiol.Immunol.(Berl) 187:23-42
    Abstract: We assessed whether the intracellular bacterium Chlamydia pneumoniae was present in post-mortem brain samples from patients with and without late-onset Alzheimer's disease (AD), since some indirect evidence seems to suggest that infection with the organism might be associated with the disease. Nucleic acids prepared from those samples were screened by polymerase chain reaction (PCR) assay for DNA sequences from the bacterium, and such analyses showed that brain areas with typical AD-related neuropathology were positive for the organism in 17/19 AD patients. Similar analyses of identical brain areas of 18/19 control patients were PCR-negative. Electron- and immunoelectron-microscopic studies of tissues from affected AD brain regions identified chlamydial elementary and reticulate bodies, but similar examinations of non-AD brains were negative for the bacterium. Culture studies of a subset of affected AD brain tissues for C. pneumoniae were strongly positive, while identically performed analyses of non-AD brain tissues were negative. Reverse transcription (RT)-PCR assays using RNA from affected areas of AD brains confirmed that transcripts from two important C. pneumoniae genes were present in those samples but not in controls. Immunohistochemical examination of AD brains, but not those of controls, identified C. pneumoniae within pericytes, Microglia, and astroglia. Further immunolabelling studies confirmed the organisms' intracellular presence primarily in areas of neuropathology in the AD brain. Thus, C. pneumoniae is present, viable, and transcriptionally active in areas of neuropathology in the AD brain, possibly suggesting that infection with the organism is a risk factor for late-onset AD

  334. Blain H, Jeandel C (1998) [Alzheimer disease. Epidemiology, genetics and physiopathological hypotheses]. Presse Med. 27:725-730
    Abstract: RISK FACTORS: Aging is the chief risk factor for Alzheimer's disease (AD). Other risk factors are aluminum in drinking water, diabetes mellitus, head trauma. Protective factors are: higher education, cigarette smoking, nonsteroidal anti-inflammatory drugs and estrogen use. GENETIC FACTORS: Mutations of presenilins 1 and 2 and of the APP gene in families with early-onset AD. Apolipoprotein E polymorphism in late-onset familial and sporadic AD. PATHOGENIC HYPOTHESES: Amyloid deposits in senile plaques and therefore dementia could be due to an overproduction of Abeta (Down's syndrome) or due to the primary (APP mutation) or secondary (role of diabetes, mellitus, apoE polymorphism: protective effect of estrogen) abnormal neurotoxic feature of Abeta. The hyperphosphorylation of tau (a protein which plays a pivotal role in the axonal transport), perhaps regulated by the apoE polymorphism could lead to neurofibrillar degeneration. Neurotoxic mediators produced by the activated Microglia (perhaps activated by neuronal damage) and oxidative stress could also be involved in the neurodegeneration

  335. Bosman GJ, Renkawek K, Van Workum FP, Bartholomeus IG, Marini S, De Grip WJ (1998) Neuronal anion exchange proteins in Alzheimer's disease pathology. J.Neural Transm.Suppl 54:248-257
    Abstract: Anion exchange (AE) proteins are present in human neurons in the brain. Immunohistochemical data indicate that their apparent expression level increases with age, and especially with degeneration in Alzheimer's disease-affected brain areas. The increase in immunoreactivity is probably caused by changes in AE structure that lead to an increased accessibility of hitherto hidden epitopes. These epitopes correspond to regions in the membrane domain that are involved in generation of senescent cell-specific antigen from AE1 in aging erythrocytes. Elucidation of the molecular nature of these changes and the underlying mechanisms will lead to insight in the processes that govern aging- and degeneration-associated perturbation of membrane integrity. The functional consequences of changes in AE structure may range from acidosis and disturbance of cytoskeleton integrity to untimely or impaired recognition of neurons by Microglia

  336. Bowser R, Reilly S (1998) Expression of FAC1 in activated Microglia during Alzheimer's disease. Neurosci.Lett. 253:163-166
    Abstract: The presence of reactive Microglia and astrocytes is a common observation in Alzheimer's disease brain. Microglia are present within the numerous beta-amyloid containing neuritic plaques, whereas reactive astrocytes usually surround the plaque perimeter. These glial cells express and secrete numerous neurotrophic and neurotoxic factors that contribute to the etiology of the disease. The molecular mechanisms that dictate glial cell activation and subsequent alternative gene expression are currently unknown. In the present study we determine that activated Microglia in AD brain express the FAC1 protein, a developmentally regulated gene product, while astrocytes fail to express significant levels of FAC1 protein. Since FAC1 is a putative DNA binding protein, expression in Microglia during AD suggests that FAC1 participates in the regulation of alternative gene expression

  337. Bradt BM, Kolb WP, Cooper NR (1998) Complement-dependent proinflammatory properties of the Alzheimer's disease beta-peptide. J.Exp.Med. 188:431-438
    Abstract: Large numbers of neuritic plaques (NP), largely composed of a fibrillar insoluble form of the beta-amyloid peptide (Abeta), are found in the hippocampus and neocortex of Alzheimer's disease (AD) patients in association with damaged neuronal processes, increased numbers of activated astrocytes and Microglia, and several proteins including the components of the proinflammatory complement system. These studies address the hypothesis that the activated complement system mediates the cellular changes that surround fibrillar Abeta deposits in NP. We report that Abeta peptides directly and independently activate the alternative complement pathway as well as the classical complement pathway; trigger the formation of covalent, ester-linked complexes of Abeta with activation products of the third complement component (C3); generate the cytokine-like C5a complement-activation fragment; and mediate formation of the proinflammatory C5b-9 membrane attack complex, in functionally active form able to insert into and permeabilize the membrane of neuronal precursor cells. These findings provide inflammation-based mechanisms to account for the presence of complement components in NP in association with damaged neurons and increased numbers of activated glial cells, and they have potential implications for the therapy of AD

  338. DeWitt DA, Perry G, Cohen M, Doller C, Silver J (1998) Astrocytes regulate Microglial phagocytosis of senile plaque cores of Alzheimer's disease. Exp.Neurol. 149:329-340
    Abstract: We have developed an in vitro model in which isolated senile plaque (SP) cores are presented to rat Microglial cells in culture. Microglia rapidly phagocytosed, broke apart, and cleared SP cores. However, when cocultured with astrocytes, Microglial phagocytosis was markedly suppressed, allowing the SPs to persist. Suppression of phagocytosis by astrocytes appears to be a general phenomena since Microglia in the presence of astrocytes showed reduced capacity to phagocytose latex beads as well. The astrocyte effect on Microglia is related in part to a diffusible factor(s) since astrocyte- but not fibroblast-conditioned media also reduced phagocytosis. These results suggest that while Microglia have the capacity to phagocytose and remove SPs, astrocytes which lie in close association to Microglia may help prevent the efficient clearance of SP material allowing them to persist in Alzheimer's disease

  339. Egensperger R, Kosel S, von Eitzen U, Graeber MB (1998) Microglial activation in Alzheimer disease: Association with APOE genotype. Brain Pathol. 8:439-447
    Abstract: Microglial cells are considered to play an important role in the pathogenesis of Alzheimer disease. Apart from producing the Alzheimer amyloid precursor (APP) as an acute phase protein, Microglial cells seem to be involved in the deposition of its amyloidogenic cleavage product, the amyloid-beta peptide (Abeta). Abeta is bound by apolipoprotein E (APOE) in an isoform-specific manner, and it has been demonstrated that inheritance of the AD susceptibility allele, APOE epsilon4, is associated with increased deposition of Abeta in the cerebral cortex. However, the relationship between APOE epsilon4 gene dose and Microglial activation is unknown. Using Microglial expression of major histocompatibility complex class II molecules as a marker, we have performed a quantitative genotype-phenotype analysis on Microglial activation in frontal and temporal cortices of 20 APOE genotyped AD brains. The number of activated Microglia and the tissue area occupied by these cells increased significantly with APOE epsilon4 gene dose. When a model of multiple linear regression was used to compare the relative influence of APOE genotype, sex, disease duration, age at death, diffuse and neuritic plaques as well as neurofibrillary tangles on Microglial activation, only APOE genotype was found to have a significant effect. Thus, the APOE gene product represents an important determinant of Microglial activity in AD. Since Microglial activation by APP has been shown to be modulated by apoE in vitro, a direct role of Microglia in AD pathogenesis is conceivable

  340. El Khoury J, Hickman SE, Thomas CA, Loike JD, Silverstein SC (1998) Microglia, scavenger receptors, and the pathogenesis of Alzheimer's disease. Neurobiol.Aging 19:S81-S84
    Abstract: The senile plaque is the pathological hallmark of Alzheimer's disease. Senile plaques are composed of beta amyloid fibrils, associated with activated Microglia, astrocytes, and dystrophic neurons. We have recently identified class A scavenger receptors as the main receptors mediating the interaction of Microglia with beta amyloid fibrils. Adhesion of Microglia to beta amyloid fibrils leads to immobilization of these cells on the fibrils, and induces them to produce reactive oxygen species. We propose that interactions of Microglial scavenger receptors with fibrillar beta amyloid may stimulate the Microglia to secrete apolipoprotein E and complement proteins, which may further contribute to neurotoxicity and neuronal degeneration. Therefore, Microglial scavenger receptors may be novel targets for therapeutic interventions in Alzheimer's disease

  341. Fenton H, Finch PW, Rubin JS, Rosenberg JM, Taylor WG, Kuo-Leblanc V, Rodriguez-Wolf M, Baird A, Schipper HM, Stopa EG (1998) Hepatocyte growth factor (HGF/SF) in Alzheimer's disease. Brain Res. 779:262-270
    Abstract: Hepatocyte growth factor (HGF/SF), is a heparin-binding polypeptide which stimulates DNA synthesis in a variety of cell types and also promotes cell migration and morphogenesis. HGF/SF mRNA has been found in a variety of tissues, including brain. In a previous study, we showed that basic fibroblast growth factor (bFGF), another heparin-binding protein is increased in Alzheimer's disease (AD), and appears to be associated with the heparan-sulfate proteoglycans bound to B/A4 amyloid (Biochem. Biophys. Res. Commun. 171 (1990) 690-696). In the present study, we examined the distribution of HGF/SF in 4% paraformaldehyde fixed samples of prefrontal cortex from control and Alzheimer patients, in order to assess the possibility that HGF/SF may be found in association with the pathologic changes which occur in Alzheimer's disease. A specific polyclonal antibody directed against HGF/SF revealed widespread HGF/SF-like immunoreactivity in both the cerebral cortex and white matter. Confocal microscopy confirmed that HGF/SF could be found in both GFAP positive astrocytes and LN3 positive Microglia cells, as well as rare scattered cortical neurons. In the AD cases studied, the immunoreactivity was increased within both the astrocytes and Microglial cells surrounding individual senile plaques. No staining was seen within the neurofibrillary tangles. Western blot analysis confirmed the normal molecular form of HGF/SF in Alzheimer's disease. Quantitative ELISA assay demonstrated a significant increase in HGF/SF in AD relative to age matched controls. These studies confirm the presence of HGF/SF immunoreactivity within neurons, astrocytes and Microglial cells. They also indicate that HGF/SF may be increased within senile plaques as a function of the gliosis and Microglial proliferation which occurs in association with these structures in Alzheimer's disease

  342. Fiala M, Zhang L, Gan X, Sherry B, Taub D, Graves MC, Hama S, Way D, Weinand M, Witte M, Lorton D, Kuo YM, Roher AE (1998) Amyloid-beta induces chemokine secretion and monocyte migration across a human blood--brain barrier model. Mol.Med. 4:480-489
    Abstract: BACKGROUND: Aside from numerous parenchymal and vascular deposits of amyloid beta (A beta) peptide, neurofibrillary tangles, and neuronal and synaptic loss, the neuropathology of Alzheimer's disease is accompanied by a subtle and chronic inflammatory reaction that manifests itself as Microglial activation. However, in Alzheimer's disease, alterations in the permeability of the blood-brain barrier and chemotaxis, in part mediated by chemokines and cytokines, may permit the recruitment and transendothelial passage of peripheral cells into the brain parenchyma. MATERIALS AND METHODS: Human monocytes from different donors were tested for their capacity to differentiate into macrophages and their ability to secrete cytokines and chemokines in the presence of A beta 1-42. A paradigm of the blood-brain barrier was constructed utilizing human brain endothelial and astroglial cells with the anatomical and physiological characteristics observed in vivo. This model was used to test the ability of monocytes/macrophages to transmigrate when challenged by A beta 1-42 on the brain side of the blood-brain barrier model. RESULTS: In cultures of peripheral monocytes, A beta 1-42 induced the secretion of proinflammatory cytokines TNF-alpha, IL-6, IL-1 beta, and IL-12, as well as CC chemokines MCP-1, MIP-1 alpha, and MIP-1 beta, and CXC chemokine IL-8 in a dose-related fashion. In the blood-brain barrier model, A beta 1-42 and monocytes on the brain side potentiated monocyte transmigration from the blood side to the brain side. A beta 1-42 stimulated differentiation of monocytes into adherent macrophages in a dose-related fashion. The magnitude of these proinflammatory effects of A beta 1-42 varied dramatically with monocytes from different donors. CONCLUSION: In some individuals, circulating monocytes/macrophages, when recruited by chemokines produced by activated Microglia and macrophages, could add to the inflammatory destruction of the brain in Alzheimer's disease

  343. Fiebich BL, Hull M, Lieb K, Schumann G, Berger M, Bauer J (1998) Potential link between interleukin-6 and arachidonic acid metabolism in Alzheimer's disease. J.Neural Transm.Suppl 54:268-278
    Abstract: Prostaglandins (PGs) and cytokines, such as interleukin-1 (IL-1) and interleukin-6 (IL-6), have been implicated in the etiopathology of various inflammatory and degenerative disorders, including Alzheimer's disease (AD). Previously, we detected the presence of IL-6 in cortices of AD patients. On the other hand, non-steroidal antiinflammatory drugs (NSAIDs), potent inhibitors of prostaglandin synthesis, have been shown to be beneficial in the treatment of AD. Until now, it remained unclear whether and how these two observations were functionally connected. Here, we show that PGs are able to induce IL-6 synthesis in a human astrocytoma cell line. PGE1 and PGE2, but not PGD2 and PGF2 alpha, led to a rapid and transient induction of astrocytic IL-6 mRNA, followed by IL-6 protein synthesis. Furthermore, PGE2 potentiated IL-1 beta-induced IL-6 mRNA synthesis. These results suggest a possible link between the release of PGs from activated Microglia and the astrocytic synthesis of IL-6, which itself may affect neuronal cells, as hypothesized for Alzheimer's disease. Finally we demonstrate that Microglia are a strong source of PGE2 synthesis indicating that these cells may act as the origin of the pathogenic cascade

  344. Frautschy SA, Yang F, Irrizarry M, Hyman B, Saido TC, Hsiao K, Cole GM (1998) Microglial response to amyloid plaques in APPsw transgenic mice. Am.J.Pathol. 152:307-317
    Abstract: Microglial activation is central to the inflammatory response in Alzheimer's Disease (AD). A recently described mouse line, Tg(HuAPP695.K670N/M671L)2576, expressing human amyloid precursor protein with a familial AD gene mutation, age-related amyloid deposits, and memory deficits, was found to develop a significant Microglial response using Griffonia simplicifolia lectin or phosphotyrosine probe to identify Microglia Both Griffonia simplicifolia lectin and phosphotyrosine staining showed increased numbers of intensely labeled, often enlarged Microglia clustered in and around plaques, consistent with Microglial activation related to beta-amyloid formation. Using quantitative image analysis of coronal phosphotyrosine-immunostained sections, transgene-positive 10- to 16-month-old, hemizygous, hybrid Tg2576 (APPsw) animals showed significantly increased Microglial density and size in plaque-forming areas of hippocampus and frontal, entorhinal, and occipital cortex. Quantitative analysis of Microglia as a function of distance from the center of plaques (double labeled for A beta peptide and Microglia) revealed highly significant, two- to fivefold elevations in Microglial number and area within plaques compared with neighboring regions. Tg2576 beta-amyloid-plaque-forming mice should be a useful system for assessing the consequences of the Microglial-mediated inflammatory response to beta-amyloid and developing anti-inflammatory therapeutic strategies for Alzheimer's disease. These results provide the first quantitative link between beta-amyloid plaque formation and Microglial activation in an animal model with neuritic plaques and memory deficits

  345. Funato H, Yoshimura M, Yamazaki T, Saido TC, Ito Y, Yokofujita J, Okeda R, Ihara Y (1998) Astrocytes containing amyloid beta-protein (Abeta)-positive granules are associated with Abeta40-positive diffuse plaques in the aged human brain. Am.J.Pathol. 152:983-992
    Abstract: Amyloid beta-protein (Abeta) is the major component of senile plaques that emerge in the cortex during aging and appear most abundantly in Alzheimer's disease. In the course of our immunocytochemical study on a large number of autopsy cases, we noticed, in many aged nondemented cases, the presence of unique diffuse plaques in the cortex distinct from ordinary diffuse plaques by immunocytochemistry. The former were amorphous, very faintly Abeta-immunoreactive plaques resembling diffuse plaques, but they stained for Abeta40 and were associated with small cells containing Abeta-positive granules. A panel of amino- and carboxyl-terminal-specific Abeta antibodies showed that such Abeta40-positive diffuse plaques and cell-associated granules were composed exclusively of amino-terminally deleted Abeta terminating at Abeta40, -42, and -43. Double immunostaining also showed that those Abeta-immunoreactive granules are located in astrocytes and not in Microglia or neurons. Immunoelectron microscopy revealed that nonfibrillar Abeta immunoreactivity was located within lipofuscin-like granules in somewhat swollen astrocytes. These findings raise the possibility that astrocytes take up Abeta and attempt to degrade it in lysosomes in the aged brain

  346. Gebicke-Haerter PJ, Lieb K, Illes P, Berger M (1998) [Microglia: mechanisms of activation and significance in pathogenesis of neuropsychiatric illnesses]. Nervenarzt 69:752-762
    Abstract: Microglia are the resident macrophages of the brain. They are the central cellular element to initiate defense mechanisms against destructive environmental influences and to facilitate regenerative processes. No other cell type of the brain is endowed with a comparably comprehensive, immunocompetent machinery like Microglia. It encompasses cell proliferation, migration and differentiation into full-blown macrophages able to present antigen and to phagocytose cell debris. Relatively little is known about these stages of Microglia activation on the cellular and molecular level, although Microglia have been described as a separate cell type of the brain as early as in the 30ies of this century by P.del Rio Hortega. This review summarizes the data that have accumulated until now in this respect and tries to embed them into a clinical framework. Special focus has been given to the role of this cell type in the development and progression of Multiple Sclerosis, HIV-associated dementia and Alzheimer's disease

  347. Giulian D, Haverkamp LJ, Yu J, Karshin W, Tom D, Li J, Kazanskaia A, Kirkpatrick J, Roher AE (1998) The HHQK domain of beta-amyloid provides a structural basis for the immunopathology of Alzheimer's disease. J.Biol.Chem. 273:29719-29726
    Abstract: The beta-amyloid peptide 1-42 (Abeta1-42), a major component of neuritic and core plaques found in Alzheimer's disease, activates Microglia to kill neurons. Selective modifications of amino acids near the N terminus of Abeta showed that residues 13-16, the HHQK domain, bind to Microglial cells. This same cluster of basic amino acids is also known as a domain with high binding affinity for heparan sulfate. Both Abeta binding to Microglia and Abeta induction of Microglial killing of neurons were sensitive to heparitinase cleavage and to competition with heparan sulfate, suggesting membrane-associated heparan sulfate mediated plaque-Microglia interactions through the HHQK domain. Importantly, small peptides containing HHQK inhibited Abeta1-42 cell binding as well as plaque induction of neurotoxicity in human Microglia. In vivo experiments confirmed that the HHQK peptide reduces rat brain inflammation elicited after infusion of Abeta peptides or implantation of native plaque fragments. Strategies which exploit HHQK-like agents may offer a specific therapy to block plaque-induced microgliosis and, in this way, slow the neuronal loss and dementia of Alzheimer's disease

  348. Giulian D (1998) A strategy for identifying immunosuppressive therapies for Alzheimer disease. Alzheimer Dis.Assoc.Disord. 12 Suppl 2:S7-14
    Abstract: There is increasing evidence that the immune system plays an important role in the pathology of Alzheimer disease (AD). The fundamental steps in this process involve induction of neurotoxic Microglia by senile plaques. Recent studies have shown that Microglia in contact with isolated plaque fragments secrete neurotoxins that can cause neuronal injury and brain damage typical of AD. In vitro models help to delineate individual steps of this activation cascade by which quiescent Microglia become neuron-killing cells. Moreover, such model systems provide rapid screening assays to identify immunosuppressive drugs that might slow brain damage brought on by neurotoxic Microglia

  349. Griffin WS, Sheng JG, Royston MC, Gentleman SM, McKenzie JE, Graham DI, Roberts GW, Mrak RE (1998) Glial-neuronal interactions in Alzheimer's disease: the potential role of a 'cytokine cycle' in disease progression. Brain Pathol. 8:65-72
    Abstract: The role of glial inflammatory processes in Alzheimer's disease has been highlighted by recent epidemiological work establishing head trauma as an important risk factor, and the use of anti-inflammatory agents as an important ameliorating factor, in this disease. This review advances the hypothesis that chronic activation of glial inflammatory processes, arising from genetic or environmental insults to neurons and accompanied by chronic elaboration of neuroactive glia-derived cytokines and other proteins, sets in motion a cytokine cycle of cellular and molecular events with neurodegenerative consequences. In this cycle, interleukin-1 is a key initiating and coordinating agent. Interleukin-1 promotes neuronal synthesis and processing of the beta-amyloid precursor protein, thus favoring continuing deposition of beta-amyloid, and activates astrocytes and promotes astrocytic synthesis and release of a number of inflammatory and neuroactive molecules. One of these, S100beta, is a neurite growth-promoting cytokine that stresses neurons through its trophic actions and fosters neuronal cell dysfunction and death by raising intraneuronal free calcium concentrations. Neuronal injury arising from these cytokine-induced neuronal insults can activate Microglia with further overexpression of interleukin-1, thus producing feedback amplification and self-propagation of this cytokine cycle. Additional feedback amplification is provided through other elements of the cycle. Chronic propagation of this cytokine cycle represents a possible mechanism for progression of neurodegenerative changes culminating in Alzheimer's disease

  350. Hauss-Wegrzyniak B, Dobrzanski P, Stoehr JD, Wenk GL (1998) Chronic neuroinflammation in rats reproduces components of the neurobiology of Alzheimer's disease. Brain Res. 780:294-303
    Abstract: Inflammatory processes may play a critical role in the pathogenesis of the degenerative changes and cognitive impairments associated with Alzheimer's disease (AD). In the present study, lipopolysaccharide (LPS) from the cell wall of gram-negative bacteria was used to produce chronic, global inflammation within the brain of young rats. Chronic infusion of LPS (0.25 microgram/h) into the 4th ventricle for four weeks produced (1) an increase in the number of glial fibrillary acidic protein-positive activated astrocytes and OX-6-positive reactive Microglia distributed throughout the brain, with the greatest increase occurring within the temporal lobe, particularly the hippocampus, (2) an induction in interleukin-1 beta, tumor necrosis factor-alpha and beta-amyloid precursor protein mRNA levels within the basal forebrain region and hippocampus, (3) the degeneration of hippocampal CA3 pyramidal neurons, and (4) a significant impairment in spatial memory as determined by decreased spontaneous alternation behavior on a T-maze

  351. Hays SJ (1998) Therapeutic approaches to the treatment of neuroinflammatory diseases. Curr.Pharm.Des 4:335-348
    Abstract: Microglia cells are present in the central nervous system and respond quickly to pathogenic stimuli in order to protect the brain. When these immunological responses activate inappropriately or are prolonged, they can contribute to the neuronal damage observed in many neurodegenerative diseases. A variety of immune system modulators including complement proteins, inflammatory cytokines such IL-1 alpha, IL-1 beta, IL-3, IL-6, TNF-alpha, and S100 beta, colony-stimulating factor-1, coagulation proteins and matrix metalloproteases are made by both Microglia and astrocytes. Additionally astrocytes, the predominant glial component of the brain, express cell-adhesion molecules, cytokine receptors and induce nitric oxide synthease. The pathophysiology of Alzheimer's disease, stroke, traumatic brain injury, and multiple sclerosis suggest that a large portion of the irreversible damage observed can be attributed to a neuroinflammatory mechanism. The immunomodulators of these diseases are reviewed and new agents within specific molecular mechanisms are presented and discussed

  352. Honda M, Akiyama H, Yamada Y, Kondo H, Kawabe Y, Takeya M, Takahashi K, Suzuki H, Doi T, Sakamoto A, Ookawara S, Mato M, Gough PJ, Greaves DR, Gordon S, Kodama T, Matsushita M (1998) Immunohistochemical evidence for a macrophage scavenger receptor in Mato cells and reactive Microglia of ischemia and Alzheimer's disease. Biochem.Biophys.Res.Commun. 245:734-740
    Abstract: Macrophage scavenger receptors (MSR) are implicated in the development of atherosclerosis and amyloid b-protein deposition in Alzheimer's disease. However, histopathological studies of MSR expression in human tissues have been hampered by a lack of specific antibodies. Using MSR-deficient mice, we successfully raised a novel monoclonal antibody against human MSR together with high-titer antisera. These antibodies specifically recognized human tissue macrophages and human MSR protein purified from differentiated THP1 cells. In normal brain, MSR staining was mainly distributed to the perivascular cells, which correspond to Mato's fluorescent granular perithelial cells (Mato cells). In the lesions of ischemia and Alzheimer's disease, a subset of Microglia stained positive for MSR. These novel antibodies are useful tools for analysis of MSR expression in human tissues

  353. Joshi SN, Crutcher KA (1998) Rat Microglia exhibit increased density on Alzheimer's plaques in vitro. Exp.Neurol. 149:42-50
    Abstract: The relationship of Microglia to senile plaques was investigated by culturing glial cells derived from neonatal rat brain on cryostat sections of Alzheimer's disease (AD) or control brain. Rat Microglia were identified by their uptake of DiI-acetylated LDL. Plaques were colocalized using Thioflavin-S staining. Although the number of Microglia attached to AD tissue sections did not differ significantly from the number on control brain tissue, the density of Microglia on senile plaques was significantly greater than on nonsenile plaque areas of the same sections. These results suggest that Microglia may have a higher affinity for senile plaques than for nonsenile plaque regions of AD brain tissue and are consistent with the hypothesis that Microglia respond to plaques

  354. Kapl D, Rudolphi KA (1998) [New pharmacologic aspects in the neurologic profile of propentofylline (Karsivan ad us. vet.)]. Tierarztl.Prax.Ausg.K.Klientiere.Heimtiere. 26:317-321
    Abstract: Propentofylline (Karsivan, Hoechst Roussel Vet) is a selective inhibitor of adenosine transport and phosphodiesterase. For several years it has been well established in the geriatric therapy of the dog improving hemodynamics in cerebral and peripheral compartments. In human medicine clinical development of this pharmaceutical has already entered an advanced stage for the long-term therapy of patients with Alzheimer's disease and vascular dementia. In the brains of senile dogs and in human patients suffering from Alzheimer's disease comparable neuropathological findings can be made. In senile dogs a distinctive correlation exists between the quantity of beta-amyloid accumulation and the degree of dementia. The extension of knowledge by clinical studies in humans and by experimental studies in animals may contribute to a deeper understanding of therapeutical approaches of cognitive dysfunction in the old dog. The xanthine derivative propentofylline [1-(5'-oxohexyl)-3-methyl-7-propylxanthine] directly interfers with the neurodegenerative process and reduces the extent of damage to brain structures. In experimental models of vascular dementia and/or Alzheimer's disease it improves cognitive functions, inhibits inflammatory processes as well as excessive activation of Microglia, formation of free radicals, cytocines and abnormal amyloid precursor proteins (APP). It stimulates synthesis and liberation of nerve growth factor (NGF) and reduces ischemic damage to the brain. In clinical studies in humans it improved cognitive functions as well as global functions and the ability to cope with tasks of routine daily life in patients suffering from Alzheimer's disease and vascular dementia

  355. Kitamura Y (1998) [Functional activation of glial cells in early and delayed episodes of the brain damage]. Nippon Yakurigaku Zasshi 111:147-156
    Abstract: Recent studies have indicated that glial cells such as astrocytes and Microglia are activated in an early and delayed episode after brain damage. However, the mechanism and function of glial activation are still unclear. I examined whether the induction of inducible nitric oxide synthase (iNOS), heme oxygenase-1 (HO-1) and major histocompatibility complex (MHC) antigen was involved in the glial activation. The microinjection of interferon-gamma and lipopolysaccharide into rat hippocampus induced MHC class II and iNOS in Microglia. The iNOS induction may be involved in the activation of tyrosine kinases and transcription factors such as signal transducer and activator of transcription-1 (STAT1) and nuclear factor-kappa B (NF-kappa B). Subsequently, neuronal cell death occurred in the hippocampus, but cell death was undetectable in both Microglia and astrocytes that expressed HO-1. Thus, induction of iNOS and HO-1 in glial cells may be involved in hippocampal neurodegeneration and resistance to oxidative stress in glial cells, respectively. In Alzheimer's disease (AD) brains, iNOS expression was at a very low level, although STAT1 and NF-kappa B were significantly increased. Also, Bcl-2, Bcl-x, Bak, Bad and p53 were increased in AD brains. These observations suggest that oxidative stress and glial activation without iNOS induction may be involved in neurodegeneration of AD brains

  356. Kobayashi K, Muramori F, Aoki T, Hayashi M, Miyazu K, Fukutani Y, Mukai M, Koshino F (1998) KP-1 is a marker for extraneuronal neurofibrillary tangles and senile plaques in Alzheimer diseased brains. Dement.Geriatr.Cogn Disord. 9:13-19
    Abstract: KP-1 immunostaining with microwave pretreatment in formalin-fixed, paraffin-embedded sections enhanced its immunoreactivity revealing extraneuronal neurofibrillary tangles (NFTs) called ghost tangles, senile plaques (SPs) and perivascular deposits as well as Microglial labelling in Alzheimer-diseased brains. KP-1 stained cored and uncored SPs, granules within the SPs, perivascular beta-amyloid protein (beta AP) and star-like beta AP deposits in cortical layer I, which was confirmed in comparison to silver-impregnated structures in the Reusche-stained or Gallyas-Schiff-stained sections. On double immunostaining with KP-1 and ubiquitin, ghost tangles were labelled by KP-1 and intraneuronal NFTs were positive for ubiquitin. A few KP-1-positive granules deposits different from amyloid core were found within the SPs and the outer margin of amyloid cores of SPs were stained by KP-1. KP-1-positive Microglia were attached to the ubiquitin-positive intraneuronal NFTs. Microglia were more numerously labelled by CR3/43 than by KP-1, and CR3/43-positive Microglia were found to be preferentially attached to SPs. As KP-1 recognizes lysosome-associated antigen CD68, similarities between KP-1 positivity and Reusche-stained structures suggested that lysosomal activity was associated with beta AP deposits and ghost tangles were involved in lysosome-associated processes. It is speculated that lysosomes play a role in the process of ghost tangle formation and in beta AP deposits leading to SP formation

  357. Kobayashi K, Fukutani Y, Hayashi M, Miyazu K, Muramori F, Aoki T, Mukai M, Sasaki K, Isaki K, Koshino Y (1998) Non-familial olivopontocerebellar atrophy combined with late onset Alzheimer's disease: a clinico-pathological case report. J.Neurol.Sci. 154:106-112
    Abstract: A 76-year-old woman with olivopontocerebellar atrophy (OPCA) presented with progressive intellectual deterioration. She showed cerebellar ataxia and muscle atrophy and weakness, and gradually developed generalized dementia with visuospatial disturbance. An autopsy revealed numerous senile plaques (SPs), neurofibrillary tangles (NFTs) and neuropil threads particularly in the CA1, subiculum and entorhinal cortex and to a lesser degree in the cerebral neocortex shown by immunostaining and specific silver impregnation techniques. The nucleus basalis of Meynert had numerous NFTs with fibrillary gliosis and neuronal cell loss. The basis pontis was markedly atrophied and the pontine nucleus had severe neuronal depopulation and gliosis. The pontine transverse fibers were demyelinated with their axons being fragmented. The cerebellar white matter was also severely degenerated. The striatum, Onuf's and intermediolateral nuclei of the spinal cord remained unchanged. Ubiquitin immunohistochemistry and Gallyas silver impregnation technique revealed oligodendroglial inclusions in the pontine nucleus, corticopontine tract, cerebral and cerebellar white matter. On double immunostaining of KP1 and ubiquitin, globular neurite SPs encircled by KP1-positive fibrous structures were found in the hippocampus and cerebral neocortex. The curly neurite SPs contained KP1-positive granules. The KP1-positive Microglial cells were distributed widely in the cerebral white matter and HLA-DR-positive ones were found around the SPs. The present case showed generalized dementia compatible with Alzheimer's disease (AD) and had a pathologically limbic type of late onset AD. This is the first case where AD affected non-familial OPCA

  358. Kopec KK, Carroll RT (1998) Alzheimer's beta-amyloid peptide 1-42 induces a phagocytic response in murine Microglia. J.Neurochem. 71:2123-2131
    Abstract: Beta-amyloid (A beta) peptides are a key component of the senile plaques that characterize Alzheimer's disease. Cytokine-producing Microglia have been shown to be intimately associated with amyloid deposits and have also been implicated as scavengers responsible for clearing A beta deposits. However, little is known about the initial activation of these Microglia or the effect of A beta on phagocytosis. Murine BV-2 Microglia were used to assess the effect of synthetic A beta 1-42 on phagocytosis by quantifying uptake of fluorescent microspheres, acetylated low-density lipoproteins, and zymosan particles by flow cytometry. A beta 1-42 stimulated Microglial phagocytosis in a time- and dose-dependent manner. A beta fibrils produced the greatest potentiation, and once activated, phagocytosis remained elevated after removal of A beta from the cultures. A beta-stimulated phagocytosis could be blocked if proteoglycans were first complexed to A beta fibrils. These data suggest that A beta fibrils act as an immune signal to stimulate Microglial phagocytosis and that extracellular matrix molecules may modify A beta function

  359. Licastro F, Mallory M, Hansen LA, Masliah E (1998) Increased levels of alpha-1-antichymotrypsin in brains of patients with Alzheimer's disease correlate with activated astrocytes and are affected by APOE 4 genotype. J.Neuroimmunol. 88:105-110
    Abstract: Levels of alpha-1-antichymotrypsin (ACT) were higher in brain homogenates of patients with Alzheimer's disease (AD) than controls. Brain tissues from the same patients and controls were immunostained with antibodies specific for Microglia or astrocytes, the leukocyte common antigen (CD45) and glial fibrillary acidic protein (GFAP), respectively. Both activated CD45 and GFAP cells were increased in AD. Astroglia were divided into scattered (CD45sc) and clustered Microglia (CD45cl) or scattered (GFAPsc) and clustered astrocytes (GFAPcl). Clustered cells were defined according their tendency to form focal aggregates. CD45cl and GFAPcl cells were present only in AD brain, while CD45sc and GFAPsc positive cells were present either in AD or control brains, with AD brains showing increased numbers of both cell types. A positive correlation between brain ACT levels and the number of GFAPsc positive cells was present in AD. AD patients with APOE 4 allele showed increased levels of ACT and increased CD45sc positive cells. Elevated ACT levels in the brain of AD patients could be interpreted as a metabolic response of astrocytes which might modulate the potentially deleterious activation of Microglia cells

  360. Licastro F, Davis LJ, Pedrini S, Galasko D, Masliah E (1998) Prostaglandin E2 induced polymerization of human alpha-1-antichymotrypsin and suppressed its protease inhibitory activity: implications for Alzheimer's disease. Biochem.Biophys.Res.Commun. 249:182-186
    Abstract: Different molecular forms of alpha-1-antichymotrypsin (ACT) in sera and cerebrospinal fluids from patients with Alzheimer's disease (AD) were detected. Monomeric and polymeric ACT were observed by polyacrylamide gel electrophoresis of both sera and cerebrospinal fluids. ACT polymers were increased in AD patients with the apolipoprotein E (APOE) 4 allele. Increased levels of inactive ACT molecules were also detected in brain homogenates of patients with the APOE 4 allele. Experimental conditions promoting in vitro polymerization of ACT and the effect of polymerization on the biological activity of this serpin were also explored. Incubation of this serpin with prostaglandins of E series (PGE 2) induced ACT polymerization and decreased its activity. Amyloid beta-peptide1-42 did not significantly affected the biological activity of ACT. Inactivation of protease inhibitors by inflammatory molecules such as PGE 2 released from activated Microglia in AD brains may promote amyloid deposition and neurodegeneration

  361. Lombardi VR, Garcia M, Cacabelos R (1998) Microglial activation induced by factor(s) contained in sera from Alzheimer-related ApoE genotypes. J.Neurosci.Res. 54:539-553
    Abstract: Several factors that increase the likelihood of developing Alzheimer's disease (AD) have already been identified. A correct evaluation of these may contribute to a better understanding of the etiology of the disease. The risk of developing AD definitely increases with (a) age, (b) head injuries, (c) family history of AD or Down syndrome, (d) sex (higher prevalence of AD in women), (e) vascular disease, (f) exposure to environmental toxins, (g) infectious processes, or (h) changes in immune function, and recent advances in molecular genetics have suggested that genetic predisposition (i) can be considered one of the most important risk factors in the development of AD. A significant increase in the number of amyloid plaques in AD patients with an apolipoprotein E4 (ApoE) allele has been observed and the results of several genetic studies indicate that the etiology of this neurodegenerative disease is associated with the presence of the allele E4 of ApoE. A potential source of damage in the AD brain is an altered response triggered by Microglial activation, which is associated with amyloid plaques. It has become evident that a dysregulation of cytokine release appears within lesions of many types of brain disorders including infection, trauma, stroke, and neurodegenerative diseases. Many studies have shown that Microglia secrete both cytokines and cytotoxins and since reactive Microglia appears in nearly every type of brain damage, it is likely that their secreted products ultimately help to determine the rate of damaged brain tissue. In this study, in vitro cell cultures were established to investigate the effect of different concentrations of human sera (2.5% and 10%) with specific ApoE genotypes from Alzheimer's and non-Alzheimer's subjects on ameboid and flat Microglial cells obtained from neonatal rat hippocampi. Results show that a modulation in the proliferation and activation of Microglial cells was obtained and that AD sera, mainly in the ApoE 3/4 and 4/4 genotype contain factor(s) which are able to induce morphological changes, as measured by an increase in the ameboid cell type. In addition, major histocompatibility complex (MHC) class II antigen expression, as measured by flow cytometric analysis, and interleukin-1beta (IL-1beta) release as measured by enzyme linked immunoadsorbent assay (ELISA), in comparison with control groups and lipopolysaccharide (LPS)-treated cells, clearly demonstrate a direct effect of ApoE 3/4 and 4/4 and/or an indirect effect mediated by the release of IL-1beta on Microglia activation. These results strongly suggest that primary in vitro Microglial cell cultures can be used as a screening model to test human sera as well as the effect of new potential drugs aimed at down-regulating Microglia activation

  362. Lombardi VR, Garcia M, Cacabelow R (1998) APOE-induced Microglial activation: an in vitro assay to screen sera from Alzheimer's disease patients and novel therapeutic compounds. Methods Find.Exp.Clin.Pharmacol. 20:377-386
    Abstract: Recent advances in molecular genetics have suggested that genetic predisposition can be considered one of the most important risk factors for Alzheimer's disease (AD) development. A significant increase in the number of amyloid plaques in AD patients with an apolipoprotein E4 (APOE) allele has been observed and the results of several genetic studies indicate that the etiology of this neurodegenerative disease is associated with the presence of the allele E4 of APOE gene. A potential source of damage in the AD brain is an altered response triggered by Microglial activation, which is associated with senile plaque formation. In this study, in vitro cell cultures were established to investigate the effect of different concentrations of human sera (2.5% and 10%) with specific APOE genotypes from Alzheimer and non-Alzheimer subjects on ameboid and flat Microglial cells obtained from adult rat hippocampus. Results show that this in vitro test can be applied as an in vitro model to test specific responses of Microglia to human sera as well as a primary screening procedure to evaluate the effect of novel compounds for the treatment of AD and neuroimmune-associated disorders

  363. Mackenzie IR, Munoz DG (1998) Nonsteroidal anti-inflammatory drug use and Alzheimer-type pathology in aging. Neurology 50:986-990
    Abstract: Anti-inflammatory drugs have been suggested as a possible treatment for Alzheimer's disease (AD). The association of immune proteins and immune-competent Microglial cells with senile plaques (SP) in both AD and normal aging suggests that these drugs may be able to modify the course of AD, either by interfering with SP formation or by suppressing the inflammation associated with SP. We compared postmortem brain tissue from elderly, nondemented, arthritic patients with a history of chronic nonsteroidal anti-inflammatory drug (NSAID) use (n = 32, aged 77 +/- 7 years) and nondemented control subjects with no history of arthritis or other condition that might promote the regular use of NSAIDs (n = 34, aged 77 +/- 6 years). In both the NSAID-treated group and control subjects, 59% of patients had some SP. There was no difference between the two groups in the mean number of plaques or in the number of specific SP subtypes (diffuse or neuritic). The degree of neurofibrillary pathology was also similar. Activated Microglia were identified using CR3/43, an anti-MHC class II antibody. Both patient age and the presence of SP correlated positively with the number of CR3/43+ Microglia (p < 0.02), whereas NSAID use was associated with less Microglial activation (p < 0.01). Control patients with SP had almost three times the number of activated Microglia as NSAID-treated patients with SP (11 versus 4 cells/mm2, p < 0.02). These results suggest that if NSAID use is effective in treating AD, the mechanism is more likely to be through the suppression of Microglial activity than by inhibiting the formation of SP or neurofibrillary tangles

  364. Marx F, Blasko I, Pavelka M, Grubeck-Loebenstein B (1998) The possible role of the immune system in Alzheimer's disease. Exp.Gerontol. 33:871-881
    Abstract: Currently, there is little doubt that the immune system plays a role in the neurodegenerative process in Alzheimer's disease (AD). Inflammatory proteins such as complement components, enzymes, eicosanoids, and cytokines are found in association with cerebral amyloid plaques and may exacerbate the fundamental pathology of AD, by stimulating Amyloid beta (A beta) production, supporting its aggregation and increasing its cytotoxicity. Activated Microglia and astrocytes are the main source of these proteins, and A beta may trigger their release. Interestingly, there are also indications that the immune system may play a protective role against the development of AD. Microglial cells have been shown to degrade A beta, and recent evidence suggests that autoreactive A beta-specific T cells may be relevant to the elimination of the peptide. This mechanism seems, however, impaired in the majority of patients with AD. The immune system seems thus to represent a natural line of defense against the accumulation of dangerous amyloidogenic substances. Impairment of this specific immunological defense mechanism and the failure to eliminate a toxic metabolite can be the basis for a chronic nonspecific inflammatory process in the brain, as described above. AD is a good example how an immune response initially aiming at maintaining the integrity of the body may fail and consequently lead to tissue destruction and neuronal loss

  365. McGeer EG, McGeer PL (1998) The importance of inflammatory mechanisms in Alzheimer disease. Exp.Gerontol. 33:371-378
    Abstract: Lesions in such chronic neurodegenerative disorders as Alzheimer disease (AD), Parkinson disease, the parkinsonism dementia complex of Guam, and amyotrophic lateral sclerosis have associated with them a variety of proteins known to be involved in inflammatory processes. This is particularly true of AD, where inflammatory reactions are thought to be important contributors to the neuronal loss. Proteins present include complement proteins, complement inhibitors, acute phase reactants, inflammatory cytokines, proteases, and protease inhibitors. Studies of cultured human astrocytes and Microglia, obtained from postmortem brain, have established that nearly all of these proteins are produced by one or another of these cell types. Human neurons also produce many inflammatory proteins and their inhibitors, creating complex interactions. Accumulations of amyloid and extracellular tangles apparently act as irritants, causing the activation of complement, the initiation of reactive changes in Microglia, and the release of potentially neurotoxic products. Such products include the membrane attack complex, oxygen free radicals, and excess glutamate. Twenty epidemiological studies that have been published to date indicate that populations taking antiinflammatory drugs have a significantly reduced prevalence of AD or a slower mental decline. One small clinical trial with indomethacin showed arrest of the disease over a six-month period. Therapeutic intervention in key inflammatory processes holds great promise for the amelioration of AD and possibly other neurodegenerative disorders

  366. McGeer PL, McGeer EG (1998) Mechanisms of cell death in Alzheimer disease--immunopathology. J.Neural Transm.Suppl 54:159-166
    Abstract: Lesions in such chronic neurodegenerative disorders as Alzheimer disease, Parkinson disease, the parkinsonism dementia complex of Guam and amyotrophic lateral sclerosis have associated with them a variety of proteins known to be involved in inflammatory processes. This is particularly true of Alzheimer disease where inflammatory reactions are thought to be important contributors to the neuronal loss. They include complement proteins, complement inhibitors, acute phase reactants, inflammatory cytokines, proteases and protease inhibitors. Studies of cultured human astrocytes and Microglia, obtained from postmortem brain, have established that nearly all of these proteins are produced by one or another of these cell types. Human neurons also produce many inflammatory proteins and their inhibitors, creating complex interactions. Accumulations of amyloid and extracellular tangles apparently act as irritants, causing the activation of complement, the initiation of reactive changes in Microglia, and the release of potentially neurotoxic products. Such products include the membrane attack complex, oxygen free radicals and excess glutamate. Twenty epidemiological studies that have been published to data indicate that populations taking antiinflammatory drugs have a significantly reduced prevalence of Alzheimer disease or a slower mental decline. One small clinical trial with indomethacin showed arrest of the disease over a 6 month period. Therapeutic intervention in key inflammatory processes holds great promise for the amelioration of Alzheimer disease and possibly other neurodegenerative disorders

  367. McGeer PL, McGeer EG (1998) Glial cell reactions in neurodegenerative diseases: pathophysiology and therapeutic interventions. Alzheimer Dis.Assoc.Disord. 12 Suppl 2:S1-S6
    Abstract: A variety of proteins known to be involved in inflammatory processes are associated with lesions in chronic neurodegenerative disorders such as Alzheimer disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). This is particularly true of AD, in which inflammatory reactions are believed to be important contributors to the neuronal loss. Inflammatory proteins associated with AD include complement proteins, complement inhibitors, acute-phase reactants, inflammatory cytokines, proteases, and protease inhibitors. Studies of cultured human astrocytes and Microglia obtained from postmortem brain have established that almost all of these proteins are produced by one or the other of these two cell types. Human neurons also produce many inflammatory proteins and their inhibitors, creating complex interactions. Accumulations of amyloid, extracellular tangles, or Lewy bodies apparently act as irritants, causing the activation of complement, the initiation of reactive changes in Microglia, and the release of potentially neurotoxic products such as the membrane attack complex, oxygen free radicals, and excess glutamate. A number of epidemiologic studies indicate that populations taking anti-inflammatory drugs have a sharply reduced prevalence of AD. One small clinical trial with indomethacin showed arrest of the disease over a 6-month period. Therapeutic intervention in key inflammatory processes holds great promise for the amelioration of AD and possibly other neurodegenerative disorders

  368. McRae A, Ling EA, Schubert P, Rudolphi K (1998) Properties of activated Microglia and pharmacologic interference by propentofylline. Alzheimer Dis.Assoc.Disord. 12 Suppl 2:S15-S20
    Abstract: Ameboid Microglia are activated macrophages in the developing brain. With age, these cells undergo gradual transformation into the adult form, known as ramified or resting Microglia. In response to neuronal insults, Microglia change their morphology and immunophenotype and proliferate to become full-blown brain macrophages. Microglia release a battery of neurotoxic substances. Responses to neuronal damage occur at various intervals after the insult, suggesting that Microglia may be an attractive target for pharmacologic intervention. The cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients contains antibodies that recognize activated Microglia in the developing rat and in the ischemic gerbil brain. These results suggest that AD shares common mechanisms related to the activation of Microglia with both these experimental models. In vitro, the xanthine derivative propentofylline (PPF) depresses the production of reactive oxygen intermediates produced by macrophages. To appreciate in vivo interactions of PPF, two models were employed: developing rats and adult gerbils exposed to ischemia. Newborn rats were administered PPF (10 mg/kg) for 7 days. Gerbils were exposed to 5 min of transient forebrain ischemia and received PPF (10 mg/kg) 24 h later until the day before sacrifice. Animals were sacrificed at 7 or 14 days after reperfusion. Brains were processed for immunocytochemistry. Reactive Microglia were visualized with monoclonal antibodies OX18 and OX42 or AD-CSF Microglia antibodies. In the case of ischemia, an antibody against the amyloid precursor protein (APP) (residues 676-695) was included. Newborn rats receiving PPF for 7 days displayed a dramatic reduction in the number of activated Microglia compared with untreated littermates. Ischemic control in gerbils showed complete nerve death, accumulations of APP, and enhanced Microglial reactivity. In gerbils receiving PPF, APP accumulation was absent or very slight, and activated Microglia were downregulated. The ability of PPF to interfere with activated Microglia suggests that this agent may be useful for slowing progressive nerve cell death associated with AD, which is considered to be largely influenced by pathologic glial reactions

  369. Mielke R, Moller HJ, Erkinjuntti T, Rosenkranz B, Rother M, Kittner B (1998) Propentofylline in the treatment of vascular dementia and Alzheimer-type dementia: overview of phase I and phase II clinical trials. Alzheimer Dis.Assoc.Disord. 12 Suppl 2:S29-S35
    Abstract: Pathophysiologic processes common to both vascular (multi-infarct) dementia and dementia of the Alzheimer type may include Microglial activation with resultant generation of inflammatory cytokines and neurotoxic free radicals, decreased secretion of nerve growth factor by astrocytes, excess release of glutamate with associated neurotoxicity, and loss of cholinergic neurons. The functional benefits and neuroprotective effects of propentofylline (PPF) stem from its interference with these overlapping pathways of neurodegeneration. The clinical pharmacology and safety of PPF were studied in a number of phase I studies in healthy young and elderly adults and in patients with renal or hepatic impairment. These studies have shown that PPF 300 mg t.i.d. is safe and well tolerated when taken on an empty stomach 1 h before meals. In a randomized, double-blind phase II study involving 190 elderly subjects with clinically and psychometrically documented mild to moderate dementia, 12 weeks of PPF therapy produced significantly greater improvements than placebo in Gottfries-Brane-Steen (GBS) scores, Mini-Mental State Examination (MMSE) scores, and Clinical Global Impression (CGI) ratings. A subsequent phase II study using positron emission tomography (PET) revealed that cortical glucose metabolism improved significantly in patients with vascular dementia after 12 weeks of PPF treatment but deteriorated significantly with placebo. A third phase II study, which enrolled patients with Alzheimer-type dementia, demonstrated that PPF significantly enhanced functional reserve, as reflected by increases in regional cerebral glucose metabolism after stimulation with a verbal memory task. In contrast, patients randomized to placebo exhibited a significant decline in functional activation and significant worsening in their MMSE scores over the course of this 12-week study. Propentofylline proved to be safe, well tolerated, and free of severe side effects in all three of these phase II trials. Phase I trial results suggest that significant food interactions occur with PPF, indicating that the drug should be taken on an empty stomach 1 h before meals. Phase II trial results indicate that PPF yields clinically measurable improvements in the symptoms of dementia and prevents loss of stimulation-related increases in glucose metabolism over a treatment period of 3 months. Whether these results indicate that PPF can slow the progression of dementia can be determined only by long-term trials specifically designed to determine the drug's effect on disease progression

  370. Munch G, Schinzel R, Loske C, Wong A, Durany N, Li JJ, Vlassara H, Smith MA, Perry G, Riederer P (1998) Alzheimer's disease--synergistic effects of glucose deficit, oxidative stress and advanced glycation endproducts. J.Neural Transm. 105:439-461
    Abstract: Many approaches have been undertaken to understand Alzheimer's disease (AD) but the heterogeneity of the etiologic factors makes it difficult to define the clinically most important factor determining the onset and progression of the disease. However, there is increasing evidence that the previously so-called "secondary factors" such as a disturbed glucose metabolism, oxidative stress and formation of "advanced glycation endproducts" (AGEs) and their interaction in a vicious cycle are also important for the onset and progression of AD. AGEs are protein modifications that contribute to the formation of the histopathological and biochemical hallmarks of AD: amyloid plaques, neurofibrillary tangles and activated Microglia. Oxidative modifications are formed by a complex cascade of dehydration, oxidation and cyclisation reactions, subsequent to a non-enzymatic reaction of sugars with amino groups of proteins. Accumulation of AGE-crosslinked proteins throughout life is a general phenomenon of ageing. However, AGEs are more than just markers of ageing since they can also exert adverse biologic effects on tissues and cells, including the activation of intracellular signal transduction pathways, leading to the upregulation of cytokine and free radical production (oxidative stress). Oxidative stress is involved in various divergent events leading to cell damage, including an increase in membrane rigidity, DNA strand breaks and an impairment in glucose uptake. In addition, other age-related metabolic changes such as depletion of antioxidants or decreased energy production by a disturbed glucose metabolism diminish the ability of the cell to cope with the effects of radical-induced membrane, protein and DNA damage. With our improving understanding of the molecular basis for the clinical symptoms of dementia, it is hoped that the elucidation of the etiologic causes, particularly the positive feedback loops involving radical damage and a reduced glucose metabolism, will help to develop novel "neuroprotective" treatment strategies able to interrupt this vicious cycle of oxidative stress and energy shortage in AD

  371. Murphy GM, Jr., Yang L, Cordell B (1998) Macrophage colony-stimulating factor augments beta-amyloid-induced interleukin-1, interleukin-6, and nitric oxide production by Microglial cells. J.Biol.Chem. 273:20967-20971
    Abstract: In Alzheimer's disease (AD), a chronic cerebral inflammatory state is thought to lead to neuronal injury. Microglia, intrinsic cerebral immune effector cells, are likely to be key in the pathophysiology of this inflammatory state. We showed that macrophage colony-stimulating factor, a Microglial activator found at increased levels in the central nervous system in AD, dramatically augments beta-amyloid peptide (betaAP)-induced Microglial production of interleukin-1, interleukin-6, and nitric oxide. In contrast, granulocyte macrophage colony-stimulating factor, another hematopoietic cytokine found in the AD brain, did not augment betaAP-induced Microglial secretory activity. These results indicate that increased macrophage colony-stimulating factor levels in AD could magnify betaAP-induced Microglial inflammatory cytokine and nitric oxide production, which in turn could intensify the cerebral inflammatory state by activating astrocytes and additional Microglia, as well as directly injuring neurons

  372. Nakai M, Hojo K, Taniguchi T, Terashima A, Kawamata T, Hashimoto T, Maeda K, Tanaka C (1998) PKC and tyrosine kinase involvement in amyloid beta (25-35)-induced chemotaxis of Microglia. Neuroreport 9:3467-3470
    Abstract: Microglia are activated by amyloid beta (Abeta) in vivo and in vitro, and Abeta-activated Microglia may be involved in the pathogenesis of Alzheimer's disease (AD). We investigated the mechanism of Microglial chemotaxis induced by Abeta (25-35), an active fragment of Abeta. Abeta (25-35) 0.1 and 1 nM stimulated Microglial chemotaxis. The protein kinase C (PKC) inhibitors chelerythrine (0.5 and 2 microM), calphostin C (1 microM) and staurospine (10 nM) significantly inhibited the Microglial chemotaxis induced by Abeta (25-35) (1 nM). The chemotactic effect of Abeta (25-35) on Microglia was desensitized by pretreatment of Microglia with 1 ng/ml 12-O-tetradecanoylphorbol 13-acetate (TPA). Pretreatment of cells with Abeta (25-35) (1 nM) also desensitized the chemotactic effect by Abeta (25-35) (1 nM). The desensitization by TPA or Abeta (25-35) was inhibited when staurosporine was present in the pretreatment media. The tyrosine kinase inhibitor herbimycin A (0.1 and 1 microM) significantly inhibited the Microglial chemotaxis induced by Abeta (25-35) (1 nM). Based on these observations, it seems likely that PKC and tyrosine kinase are involved in the Abeta-induced chemotaxis of Microglia

  373. Nakajima K, Kohsaka S (1998) [Microglia: function in the pathological state]. No To Shinkei 50:5-16

  374. Nishimura I, Uetsuki T, Dani SU, Ohsawa Y, Saito I, Okamura H, Uchiyama Y, Yoshikawa K (1998) Degeneration in vivo of rat hippocampal neurons by wild-type Alzheimer amyloid precursor protein overexpressed by adenovirus-mediated gene transfer. J.Neurosci. 18:2387-2398
    Abstract: In an attempt to elucidate the pathological implications of intracellular accumulation of the amyloid precursor protein (APP) in postmitotic neurons in vivo, we transferred APP695 cDNA into rat hippocampal neurons by using a replication-defective adenovirus vector. We first improved the efficiency of adenovirus-mediated gene transfer into neurons in vivo by using hypertonic mannitol. When a beta-galactosidase-expressing recombinant adenovirus suspended in 1 M mannitol was injected into a dorsal hippocampal region, a number of neurons in remote areas were positively stained, presumably owing to increased retrograde transport of the virus. When an APP695-expressing adenovirus was injected into the same site, part of the infected neurons in the hippocampal formation underwent severe degeneration in a few days, whereas astrocytes near the injection site showed no apparent degeneration. These degenerating neurons accumulated different epitopes of APP, and beta/A4 protein (Abeta)-immunoreactive materials were undetected in the extracellular space. A small number of degenerating neurons showed nuclear DNA fragmentation. Electron microscopic examinations demonstrated that degenerating neurons had shrunken perikarya along with synaptic abnormalities. Microglial cells/macrophages were often found in close proximity to degenerating neurons, and in some cases they phagocytosed these neurons. These results suggest that intracellular accumulation of wild-type APP695 causes a specific type of neuronal degeneration in vivo in the absence of extracellular Abeta deposition

  375. Oka M, Katayama S, Watanabe C, Noda K, Mao JJ, Nakamura S (1998) Argyrophilic structures stimulate glial reactions in neurofibrillary tangles and senile plaques. Neurol.Res. 20:121-126
    Abstract: Neurofibrillary tangles (NFT) and senile plaques (SP) contain various pathological structures, and the majority of these pathological structures are argyrophilic. To investigate the glial reactions of the argyrophilic substance, we performed immunohistochemistry for Microglia or for astroglia after Gallyas-Braak staining, which is one of the most sensitive silver impregnation techniques detecting argyrophilic structures in NFT and SP. We found that extracellular argyrophilic structures in NFT and SP showed glial reactions, and we observed reactive Microglia in the center of NFT and SP in contrast to astroglia, which were situated in the periphery. These findings suggest that the exposed argyrophilic components in the extracellular space stimulate both glial reactions, but that there is a striking difference in localization between Microglia and astroglia

  376. Pasinetti GM (1998) Cyclooxygenase and inflammation in Alzheimer's disease: experimental approaches and clinical interventions. J.Neurosci.Res. 54:1-6
    Abstract: Many epidemiological studies suggest that use of non-steroidal anti-inflammatory drugs (NSAIDs) delay or slow the clinical expression of Alzheimer's disease (AD). While it has been demonstrated that neurodegeneration in AD is accompanied by specific inflammatory mechanisms, including activation of the complement cascade and the accumulation and activation of Microglia, the mechanism by which NSAIDs might affect these or other pathophysiological processes relevant to AD has been unclear. New evidence that cyclooxygenase (COX) is involved in neurodegeneration along with the development of selective COX inhibitors has led to renewed interest in the therapeutic potential of NSAIDs in AD

  377. Popovic M, Caballero-Bleda M, Puelles L, Popovic N (1998) Importance of immunological and inflammatory processes in the pathogenesis and therapy of Alzheimer's disease. Int.J.Neurosci. 95:203-236
    Abstract: The contribution of autoimmune processes or inflammatory components in the etiology and pathogenesis of Alzheimer's disease (AD) has been suspected for many years. The presence of antigen-presenting, HLA-DR-positive and other immunoregulatory cells, components of complement, inflammatory cytokines and acute phase reactants have been established in tissue of AD neuropathology. Although these data do not confirm the immune response as a primary cause of AD, they indicate involvement of immune processes at least as a secondary or tertiary reaction to the preexisting pathogen and point out its driving-force role in AD pathogenesis. These processes may contribute to systemic immune response. Thus, experimental and clinical studies indicate impairments in both humoral and cellular immunity in an animal model of AD as well as in AD patients. On the other hand, anti-inflammatory drugs applied for the treatment of some chronic inflammatory diseases have been shown to reduce risk of AD in these patients. Therefore, it seems that anti-inflammatory drugs and other substances which can control the activity of immunocompetent cells and the level of endogenous immune response can be valuable in the treatment of AD patients

  378. Qiu WQ, Walsh DM, Ye Z, Vekrellis K, Zhang J, Podlisny MB, Rosner MR, Safavi A, Hersh LB, Selkoe DJ (1998) Insulin-degrading enzyme regulates extracellular levels of amyloid beta-protein by degradation. J.Biol.Chem. 273:32730-32738
    Abstract: Excessive cerebral accumulation of the 42-residue amyloid beta-protein (Abeta) is an early and invariant step in the pathogenesis of Alzheimer's disease. Many studies have examined the cellular production of Abeta from its membrane-bound precursor, including the role of the presenilin proteins therein, but almost nothing is known about how Abeta is degraded and cleared following its secretion. We previously screened neuronal and nonneuronal cell lines for the production of proteases capable of degrading naturally secreted Abeta under biologically relevant conditions and concentrations. The major such protease identified was a metalloprotease released particularly by a Microglial cell line, BV-2. We have now purified and characterized the protease and find that it is indistinguishable from insulin-degrading enzyme (IDE), a thiol metalloendopeptidase that degrades small peptides such as insulin, glucagon, and atrial natriuretic peptide. Degradation of both endogenous and synthetic Abeta at picomolar to nanomolar concentrations was completely inhibited by the competitive IDE substrate, insulin, and by two other IDE inhibitors. Immunodepletion of conditioned medium with an IDE antibody removed its Abeta-degrading activity. IDE was present in BV-2 cytosol, as expected, but was also released into the medium by intact, healthy cells. To confirm the extracellular occurrence of IDE in vivo, we identified intact IDE in human cerebrospinal fluid of both normal and Alzheimer subjects. In addition to its ability to degrade Abeta, IDE activity was unexpectedly found be associated with a time-dependent oligomerization of synthetic Abeta at physiological levels in the conditioned media of cultured cells; this process, which may be initiated by IDE-generated proteolytic fragments of Abeta, was prevented by three different IDE inhibitors. We conclude that a principal protease capable of down-regulating the levels of secreted Abeta extracellularly is IDE

  379. Schubert P, Rudolphi K (1998) Interfering with the pathologic activation of Microglial cells and astrocytes in dementia. Alzheimer Dis.Assoc.Disord. 12 Suppl 2:S21-S28
    Abstract: Cascading glial cell activation is believed to play an essential pathogenic role in the development of dementia. Reactive Microglia may contribute to neuronal damage by the generation of free oxygen radicals and nitric oxide (NO), which forms the particularly aggressive peroxynitrites, and by the release of potentially neurotoxic cytokines such as tumor necrosis factor-alpha (TNF-alpha). The pathologically stimulated release of interleukin-1beta (IL-1beta) from Microglial cells triggers secondary activation of astrocytes, which are forced to proliferate and to give up their differentiated state. As a consequence, physiologically required astrocyte functions may be impaired, such as uptake of glutamate and K+ from the extracellular space and release of neurotrophic factors. At the same time, production of inflammatory proteins which, for example, promote the formation of toxic beta-amyloids, is reported to be stimulated in reactive astrocytes. Because the complex molecular signaling that controls glial cell activation is only beginning to be elaborated, we attempted to elucidate the role that has been adopted during evolution by the endogenous cell modulator adenosine. This nucleoside exerts a homeostatic effect on reactive glial cell functions by a sophisticated control of the second messenger interplay, counteracting a pathologically induced dysbalance of the Ca2+- and cAMP-dependent signaling. A strengthening of the cAMP-dependent signaling chains was found to counteract the proliferation rate, the formation of free oxygen radicals, and the stimulated release of TNF-alpha and IL-1beta in cultivated Microglia. It also helped proliferative astrocytes to regain their differentiated state and a mature ion channel pattern. The cAMP-linked homeostatic adenosine effects could be reinforced or mimicked by propentofylline, a pharmacon that raises the effective extracellular concentration of adenosine by inhibiting its cellular reuptake and increases the cellular cyclic nucleotide content by selective phosphodiesterase inhibition. We conclude that a pharmacologically reinforced homeostatic control of the pathologically altered Ca2+/cAMP crosstalk may prevent glia-related neuronal damage, providing a potential option for the treatment of dementia

  380. Schubert P, Ogata T, Miyazaki H, Marchini C, Ferroni S, Rudolphi K (1998) Pathological immuno-reactions of glial cells in Alzheimer's disease and possible sites of interference. J.Neural Transm.Suppl 54:167-174
    Abstract: A significant role of a pathological glial cell activation in the pathogenesis of Alzheimer's disease is supported by the growing evidence that inflammatory proteins, which are produced by reactive astrocytes, promote the transformation of diffuse beta-amyloid deposits into the filamentous, neurotoxic form. A number of vicious circles, driven by the release of TNF-a and free oxygen radicals from Microglial cells, may cause an upregulated Microglial activation and their production of interleukin-1 which triggers, secondarily, the crucial activation of astrocytes. Reactive functional changes of glial cells seem to be controlled by an altered balance of the second messengers Ca2+ and cAMP and can be counterregulated by the endogenous cell modulator adenosine which strengthens the cAMP-dependent signalling chain. A further reinforcement of the homeostatic adenosine effects on glial cells by pharmaca, such as propentofylline, may add to neuroprotection in Alzheimer's disease

  381. Sheng JG, Griffin WS, Royston MC, Mrak RE (1998) Distribution of interleukin-1-immunoreactive Microglia in cerebral cortical layers: implications for neuritic plaque formation in Alzheimer's disease. Neuropathol.Appl.Neurobiol. 24:278-283
    Abstract: Activated Microglia overexpressing interleukin-1 (IL-1) are prominent neuropathological features of Alzheimer's disease. We used computerized image analysis to determine the number of IL-1 alpha-immunoreactive (IL-1 alpha +) Microglia in cytoarchitectonic layers of parahippocampal gyrus (Brodmann's area 28) of Alzheimer and control patients. For cortical layers I and II, the numbers of IL-1 alpha + Microglia were similar in Alzheimer and control patients. For layers III-VI, the numbers of IL-1 alpha + Microglia were higher than that seen in layers I-II for both Alzheimer and control patients. Moreover, for layers III-VI, the number of IL-1 alpha + Microglia in Alzheimer patients was significantly greater than that in control patients (relative Alzheimer values of threefold for layer III-V and twofold for layer VI; P < 0.05 in each case). The cortical laminar distribution of IL-1 alpha + Microglia in Alzheimer patients correlated with the cortical laminar distribution of beta-amyloid precursor protein-immunoreactive (beta-APP+) neuritic plaques found in Alzheimer patients (r = 0.99, P < 0.005). Moreover, the cortical laminar distribution of IL-1 alpha + Microglia in control patients also correlated with the cortical laminar distribution of beta-APP+ neuritic plaques found in Alzheimer patients (r = 0.91, P < 0.05). These correlations suggest that pre-existing laminar distribution patterns of IL-1 alpha + Microglia (i.e. that seen in control patients) are important in determining the observed laminar distribution of beta-APP+ neuritic plaques in Alzheimer patients. These findings provide further support for our hypothesis that IL-1 is a key driving force in neuritic plaque formation in Alzheimer's disease

  382. Sheng JG, Mrak RE, Griffin WS (1998) Enlarged and phagocytic, but not primed, interleukin-1 alpha-immunoreactive Microglia increase with age in normal human brain. Acta Neuropathol.(Berl) 95:229-234
    Abstract: Microglia-mediated inflammatory responses have been implicated in the pathogenesis of neuritic plaques in Alzheimer's disease. The strong age association of Alzheimer's disease incidence suggests that events in normal aging may promote such responses. We used immunohistochemistry and computerized image analysis to determine the numbers, size, activation state, and immunoreactive intensity of interleukin-1 alpha-immunoreactive (IL-1 alpha +) Microglia in mesial temporal lobe of 20 neurologically normal individuals, 2-80 years of age. We also used Northern analysis to determine tissue levels of IL-1 alpha mRNA in an additional 11 neurologically normal individuals aged 1 day to 78 years. IL-1 alpha + Microglia were characterized as primed, enlarged, or phagocytic (enlarged with heterogeneous cytoplasmic contents) based on morphology. These three Microglial subtypes showed significant differences in size [27 +/- 1 58 +/- 2 114 +/- 6 (mean +/- SEM) micron 2/cell, respectively, P < 0.001 for each comparison] and in immunoreactive intensity [60 +/- 1 68 +/- 2 79 +/- 2 (arbitrary units), respectively, P < 0.001 or better for each comparison]. There were significant age-associated increases in the total numbers of activated IL-1 alpha + Microglia. Among Microglial subtypes, there were significant increases in the numbers of enlarged (threefold) and especially phagocytic (elevenfold), but not primed, Microglia. Tissue IL-1 alpha mRNA levels were higher in individuals over 60 than in those less than 60 (P < 0.05). The age-associated increases in Microglial activation were independent of postmortem interval, patient sex, and the presence of Alzheimer-type 'senile' changes. Age-associated increases in Microglial activation and IL-1 expression may contribute to the age-associated increased risk of Alzheimer's disease

  383. Styren SD, Kamboh MI, DeKosky ST (1998) Expression of differential immune factors in temporal cortex and cerebellum: the role of alpha-1-antichymotrypsin, apolipoprotein E, and reactive glia in the progression of Alzheimer's disease. J.Comp Neurol. 396:511-520
    Abstract: A variety of factors and processes have been implicated in the development and progression of the pathology of Alzheimer's Disease (AD), including amyloid fragment deposition, reactive gliosis, alpha-1-antichymotrypsin (ACT), and apolipoprotein E (APOE). Carriers of the APOE 4 allele have been shown to have an enhanced risk of developing AD, and the ACT signal peptide A/A genotype may modify the APOEepsilon4 risk. The protein products of these genes have been shown to enhance conversion of diffuse beta amyloid (Abeta) fibrils, which are found in diffuse plaques, to the fibrillar form found in neuritic plaques. In affected regions of AD brain, ACT and APOE colocalize with Abeta deposits and reactive Microglia and astrocytes. We examined the regional distribution of ACT, APOE, and reactive glia in temporal cortex, where neuritic plaques are abundant, and cerebellum (in areas where diffuse plaques but not neuritic plaques accumulate) to examine the relationship of these markers to the deposition of Abeta. In temporal cortex, ACT and APOE staining was localized to plaque-like profiles, reactive astrocytes, and blood vessels; human leukocyte antigen-DR (HLA-DR) and glial fibrillary acidic protein (GFAP) staining revealed focal clusters of reactive Microglia and astrocytes. In cerebellum, ACT and APOE immunoreactivity was never localized to plaque-like profiles but was weakly localized to unreactive astrocytes; weak HLA-DR and GFAP immunoreactivity was present on quiescent Microglia throughout the cerebellum. The lack of fibrillar amyloid deposits in cerebellum, despite the presence of well-characterized markers thought to mediate the production of Abeta, suggests that this brain region may be lacking certain factors necessary for fibril formation or that the cerebellum responds differently to stimuli that successfully mediate inflammation in affected cortex

  384. Takeda A, Yasuda T, Miyata T, Goto Y, Wakai M, Watanabe M, Yasuda Y, Horie K, Inagaki T, Doyu M, Maeda K, Sobue G (1998) Advanced glycation end products co-localized with astrocytes and Microglial cells in Alzheimer's disease brain. Acta Neuropathol.(Berl) 95:555-558
    Abstract: In the previous study [Takeda et al. (1996) Neurosci Lett 221: 17-21], we reported that the advanced glycation end products (AGEs) in the external space of neuronal perikarya (extraneuroperikaryal AGE deposits) were significantly abundant in the Alzheimer's brain. In this study, we investigated the spatial relationship of the extraneuroperikaryal AGE (carboxymethyllysine and pentosidine) deposits in astrocytes and Microglial cells in the Alzheimer's disease brain using double immunolabelling for AGEs and astrocyte or Microglial cell markers. Most of the extraneuroperikaryal AGE deposits were co-localized with glial fibrillary acidic protein-positive astrocytes. AGE deposit-bearing astrocytes also contained Gomori-positive granules. Furthermore, some of the extraneuroperikaryal AGE deposits were co-localized with Microglial cells. These extraneuroperikaryal AGEs may activate astrocyte and Microglia, and play a role in pathogenesis of Alzheimer's disease

  385. Thal DR, Arendt T, Waldmann G, Holzer M, Zedlick D, Rub U, Schober R (1998) Progression of neurofibrillary changes and PHF-tau in end-stage Alzheimer's disease is different from plaque and cortical Microglial pathology. Neurobiol.Aging 19:517-525
    Abstract: In terminal Alzheimer's disease (AD) the frequency of plaques was found to be reduced in single cases. To test this finding in a larger sample, and in order to determine whether the number of plaques labeled with different markers and the distribution of neurofibrillary tangles are correlated positively to each other and to the degree of dementia, a sample of 134 autopsy brains with and 15 without AD-related pathology has been examined. All of the cases were staged according to Braak and Braak. Both the frequency of plaques immunopositive for beta-amyloid, amyloid precursor protein, and apolipoprotein E and that of Microglial cells in the cortex and in the white matter were determined semiquantitatively. The content and distribution of PHF-tau was ascertained by ELISA and immunohistochemistry. Both the clinical dementia rating and the global deterioration scale were used as clinical parameters retrospectively. Correlation coefficients were calculated for all parameters and differences were evaluated statistically. With progressive distribution of neurofibrillary tangles and increasing content of PHF-tau the plaque stages and the degree of cortical Microglia reaction increased up to the Braak-stages IV and V, thereafter showing a slightly decreasing tendency in the investigated regions. In end-stage AD resorption of beta-amyloid seems to surpass its deposition. The Microglial reaction in the white matter correlated neither with the Braak-stage nor with the accumulation of amyloid. With regard to the degree of dementia, both scales correlated well with the pathological changes. Our data show that neuronal cytoskeletal alterations progressively increase with progressive dementia until the end stage of AD in contrast to the frequencies of plaques and cortical Microglial cells, and are therefore preferable for staging purposes

  386. Troncoso JC, Cataldo AM, Nixon RA, Barnett JL, Lee MK, Checler F, Fowler DR, Smialek JE, Crain B, Martin LJ, Kawas CH (1998) Neuropathology of preclinical and clinical late-onset Alzheimer's disease. Ann.Neurol. 43:673-676
    Abstract: We report on the neuropathological examinations of a 74-year-old woman with Alzheimer's disease (AD) and of her 47-year-old nondemented daughter. The brain of the mother showed fully developed pathological changes of AD. By contrast, the brain of the daughter revealed only perineuronal deposition of diffuse amyloid in cerebral cortex and striking abnormalities of the endosomal-lysosomal system, without neurofibrillary, glial, or Microglial changes. These observations suggest that amyloid deposition and endosomal-lysosomal changes are early events in late-onset AD and that they may precede the onset of dementia by several decades

  387. Unger JW (1998) Glial reaction in aging and Alzheimer's disease. Microsc.Res.Tech. 43:24-28
    Abstract: It is well-established that glial cells play an important role during injury and neurodegenerative processes in the central nervous system. In normal aging, no global glia proliferation is found morphologically, but reactive gliosis has been described in specific areas of the limbic system and neocortex that undergo selective neuronal or synaptic degeneration in nondemented elderly persons. In addition, there is an age-associated increase in the metabolic turnover of cellular proteins, such as glial fibrillary acidic protein, in human brain tissue, even without detectable signs of neurodegeneration. In contrast to the relatively moderate overall glial changes in normal aging, the close association of activated astrocytes and Microglial cells with neuritic plaques and cells undergoing neurofibrillary degeneration in Alzheimer's disease (AD), the expression of receptors for complement by glial cells, and the release of soluble cytokines strongly suggest that inflammatory processes may play an important part in the complex pathophysiological interactions that occur in AD. Understanding the role of glia in age-associated neurodegenerative disorders may provide new insights into the neurobiology of glia-neuronal interaction and may allow the development of strategies to alter the disease process. This review aims to summarize some of the important aspects of glial cells in aging and dementia

  388. Verbeek MM, Otte-Holler I, Veerhuis R, Ruiter DJ, De Waal RM (1998) Distribution of A beta-associated proteins in cerebrovascular amyloid of Alzheimer's disease. Acta Neuropathol.(Berl) 96:628-636
    Abstract: Senile plaques and cerebrovascular amyloidosis (CA) are two of the major neuropathological lesions in brains of patients with dementia of the Alzheimer type. We studied the expression of a number of amyloid beta (A beta)-associated proteins in CA, which have previously been identified in senile plaques and which were suggested to play an important role in the pathogenesis of these lesions. Our findings show that involvement of inflammatory components in CA is restricted to activation of the complement system, resulting in deposition of the complement factors C1q, C3c, C4d and the membrane attack complex C5b-9 as well as of the complement inhibitor clusterin. Furthermore, we observed expression of apolipoprotein E, amyloid P component and heparan sulfate proteoglycans in CA, whereas expression of lactoferrin was almost absent. Other inflammatory proteins, known to be present in senile plaques, such as alpha1-antichymotrypsin, alpha2-macroglobulin and intercellular adhesion molecule-1, were absent or detectable only in small amounts. These data suggest that an incomplete inflammatory response occurs in CA as compared to senile plaques. This was confirmed by the finding that the number of cells of the monocyte/macrophage lineage around CA was not increased compared to unaffected vessels. Based on their expression patterns, complement factors, apolipoprotein E and heparan sulfate proteoglycans may be produced early in the process of CA formation and may play an important role in the formation of A beta fibrils in CA. The absence of a number of A beta-associated proteins in CA in comparison to senile plaques is in support of a different pathogenesis for these two lesions

  389. Wisniewski HM, Frackowiak J (1998) Commentary to: Differences between the pathogenesis of senile plaques and congophilic angiopathy in Alzheimer disease. (J Neuropathol Exp Neurol 1997; 56:751-61). J.Neuropathol.Exp.Neurol. 57:96-98

  390. Wisniewski HM, Sadowski M, Jakubowska-Sadowska K, Tarnawski M, Wegiel J (1998) Diffuse, lake-like amyloid-beta deposits in the parvopyramidal layer of the presubiculum in Alzheimer disease. J.Neuropathol.Exp.Neurol. 57:674-683
    Abstract: A characteristic feature of the parvopyramidal layer of the presubiculum of 6 individuals with Alzheimer disease (AD) was the presence of large, evenly distributed amyloid-beta (A beta) deposits, which in the end stage of the disease occupy 80.9 +/- 12.2% of the parvopyramidal layer. The strong reaction of A beta deposits with antibodies 4G8 (17-24 amino acids, aa), 6E10 (1-17 aa), and R165 (32-42 aa), and their weak reaction with antibody R162 (32-40 aa) indicate that potentially highly fibrillogenic A beta1-42 is a major constituent of presubicular amyloid. However, A beta deposits in the presubiculum are thioflavin-S- and Congo red-negative--and thus, nonfibrillar--even after 11 to 19 years of AD. The unique properties of presubicular amyloid appear to be related to their origin; amyloid-associated proteins such as apolipoproteins E, and AI, alpha1-antichymotrypsin, and heparan sulfate proteoglycan, which are promoters of fibrillization or stabilizers of A beta in neuritic plaques, are absent; activated astrocytes, which are the source of these proteins, are also absent. The unchanged number and distribution and the resting appearance of Microglial cells revealed with RCA-I histochemistry suggest that they do not respond to diffuse A beta deposits. The source of nonfibrillar presubicular A beta is probably local neurons or neuronal projections to the parvocellular layer of the presubiculum. Neuronal, lake-like A beta deposition appears to be characteristic of AD pathology. The presubiculum is most likely the model brain structure for the study of amyloid of exclusively neuronal origin. The parvopyramidal layer of the presubiculum reveals only a small population of the neurons (2.5 +/- 2%) affected by neurofibrillary pathology

  391. Xia MQ, Berezovska O, Kim TW, Xia WM, Liao A, Tanzi RE, Selkoe D, Hyman BT (1998) Lack of specific association of presenilin 1 (PS-1) protein with plaques and tangles in Alzheimer's disease. J.Neurol.Sci. 158:15-23
    Abstract: Missense mutations in the presenilin-1 (PS-1) gene are causally related to the majority of familial early-onset Alzheimer's disease (FAD). PS-1 immunohistochemical expression in normal human brain and in brains with Alzheimer's disease (AD) has so far been controversial. Here, we report a study of PS-1 expression in brains, cell lines and peripheral blood mononuclear cells using a panel of well characterized PS-1-specific antibodies. These antibodies were characterized by immunofluorescent staining of PS-1 transfectants followed by flow cytometric analysis. In human brain, widespread neuronal staining was observed. PS-1 immunoreactivity was primarily confined to neuronal cell bodies and proximal dendrites. Weaker staining of Microglia was also detected, in accord with the finding of PS-1 immunoreactivity in monocytes. PS-1 expression is not particularly associated with neurons either containing or spared from neurofibrillary tangles, nor with senile plaques. The level of PS-1 expression does not differ between normal and AD brains. Immunoprecipitation from AD, FAD and control brains revealed only a 32 kDa N-terminal fragment and an 18-20 kDa C-terminal fragment. Little or no full length PS-1 was detected. The enriched presence of PS-1 in neurons implies an important role in neuronal function, however, the lack of apparent association of its expression with AD pathology signifies the need for a better understanding of its pathophysiological role

  392. Xia MQ, Qin SX, Wu LJ, Mackay CR, Hyman BT (1998) Immunohistochemical study of the beta-chemokine receptors CCR3 and CCR5 and their ligands in normal and Alzheimer's disease brains. Am.J.Pathol. 153:31-37
    Abstract: Chemokines belong to an expanding family of cytokines the primary function of which is recruitment of leukocytes to inflammatory sites. Recent evidence has shown their presence in the central nervous system. Because inflammatory responses have been implicated in the pathogenesis of Alzheimer's disease (AD), we studied the expression of CCR3, CCR5, and their ligands in normal and AD brains by immunohistochemistry. CCR3 and CCR5 are present on Microglia of both control and AD brains, with increased expression on some reactive Microglia in AD. Immunohistochemistry for MIP-1beta, MIP-1alpha, RANTES, eotaxin, and MCP-3 (ligands for CCR5 and/or CCR3) revealed the presence of MIP-1beta predominantly in a subpopulation of reactive astrocytes, which were more widespread in AD than control brains, and MIP-1alpha predominantly in neurons and weakly in some Microglia in both AD and controls. Many of the CCR3+ or CCR5+ reactive Microglia and MIP-1beta+ reactive astrocytes were found associated with amyloid deposits. Immunoreactivity for eotaxin, RANTES, and MCP-3 were not detected. Detection of these beta-chemokine receptors on Microglia and some of their ligands in reactive astrocytes and neurons as well as Microglia suggests a role for this system in glial-glial and glial-neuronal interactions, potentially influencing the progression of AD

  393. Yamada T, Yoshiyama Y, Kawaguchi N, Ichinose A, Iwaki T, Hirose S, Jefferies WA (1998) Possible roles of transglutaminases in Alzheimer's disease. Dement.Geriatr.Cogn Disord. 9:103-110
    Abstract: The localizations of two transglutaminases [factor XIIIa and tissue transglutaminase (tTG)] and their mRNAs were examined in human brain tissues from neurologically normal and Alzheimer disease (AD) cases, using immunohistochemical and in situ hybridization methods. In all cases, meningeal macrophages and ependymal macrophage/Microglia were positive for factor XIIIa. The mRNA encoding factor XIIIa was detected in macrophages and Microglia. As reported previously, intense staining with the antibody to factor XIIIa of a subset of Microglia was seen in the parietal cortex in AD brains. Few or no Microglia were found associated with classical senile plaques. In contrast, many labeled Microglia were associated with primitive plaques. Further-more, most of these cells were mainly seen in the subpial cortical layer but were very rare in the hippocampus. On the other hand, few factor-XIIIa-positive Microglia were found in the parietal cortices from non-neurological cases, but moderate numbers were found in their hippocampal tissues. TG and its mRNA were localized in astrocytes in all the cases. In AD, a few neurofibrillary tangles were positive to tTG. These results suggest that the subsets of Microglia which express factor XIIIa may play some roles in the early phase of AD pathology

  394. Yamada T (1998) [Molecular physiopathology of Alzheimer's disease]. Fukuoka Igaku Zasshi 89:29-33

  395. Yamaguchi H, Sugihara S, Ogawa A, Saido TC, Ihara Y (1998) Diffuse plaques associated with astroglial amyloid beta protein, possibly showing a disappearing stage of senile plaques. Acta Neuropathol.(Berl) 95:217-222
    Abstract: To clarify whether senile plaques disappear, we examined amyloid beta protein (A beta) deposits in non-demented subjects, and found novel diffuse plaques associated with astroglial A beta. Formalin-fixed paraffin-embedded sections from cortical areas were immunolabeled with a panel of A beta antibodies, and astroglial and Microglial markers. Cerebral A beta deposition was primarily found as diffuse plaques (DP) in these subjects. A subset of DP was associated with clusters of intensely A beta-positive small granules. The clusters, which were located just adjacent to astroglial nucleus, had the characteristics of lipofuscin granules and, therefore, were quite different from "small stellate deposits". Substantial amounts of A beta-positive granules were found inside astrocytes by dual labeling of A beta and glial fibrillary acid protein, and the majority of astroglial A beta immunoreactivity was located on lipofuscin granules. A beta-positive granules lacked immunoreactivity with antisera for the N-terminal region of A beta. These peculiar DP showed a much weaker staining than ordinary DP. The DP associated with astroglial A beta were found in about one third of the subjects, although the density varied widely among individuals. From these findings, we propose that DP, which are associated with the N-terminal truncated A beta in astrocytes, represent the disappearing stage of senile plaques

  396. Yang F, Sun X, Beech W, Teter B, Wu S, Sigel J, Vinters HV, Frautschy SA, Cole GM (1998) Antibody to caspase-cleaved actin detects apoptosis in differentiated neuroblastoma and plaque-associated neurons and Microglia in Alzheimer's disease. Am.J.Pathol. 152:379-389
    Abstract: During apoptosis, activation of a family of cysteine proteases related to interleukin-1beta-converting enzyme (ICE)-related proteases or "caspases" results in endoproteolytic cleavage of multiple substrates at specific aspartate residues. We have sought to develop new antibody probes for the neoepitopes in protein fragments produced by ICE-related proteolytic cleavage as specific markers of events tightly linked to apoptotic mechanisms. Here, we demonstrate that an antibody probe specific for the C terminus of a 32-kd actin fragment produced by ICE-like activity specifically labels apoptotic but not necrotic, differentiated human neuroblastoma cells in culture. Unlike probes for nonspecific DNA strand breaks confined to the nucleus or cell body, this method allows the detection of cytoskeletal fragments in cell processes as well as the perikaryon long before DNA fragmentation and cell death and therefore serves as a novel marker of apoptosis-related events in distal parts of cells such as axons and dendrites. To illustrate this new tool, we show that the antibody detects the processes and cell bodies of degenerating neurons and plaque-associated Microglia in Alzheimer's disease. In situ detection of caspase-cleaved actin provides a new means to evaluate the role of caspase activation in pathological and physiological processes

  397. Yoshiyama Y, Sato H, Seiki M, Shinagawa A, Takahashi M, Yamada T (1998) Expression of the membrane-type 3 matrix metalloproteinase (MT3-MMP) in human brain tissues. Acta Neuropathol.(Berl) 96:347-350
    Abstract: Membrane-type 3 matrix metalloproteinase (MT3-MMP) is a novel MT-MMP which has a transmembrane domain at the C terminus, and mediates activation of pro-gelatinase A, just as does MT1-MMP. Previously, we reported that MT1-MMP was expressed on Microglial cells only in the white matter [Yamada T, Yoshiyama Y, Sato H, Seiki M, Shinagawa A, Takahashi M (1995) Acta Neuropathol 90:421-424]. In the present study of both non-neurological and Alzheimer brain tissues, we examined the localization of MT3-MMP by immunohistochemistry. Anti-MT3-MMP antibodies gave positive staining of Microglial cells in all brain tissues. Positively stained Microglia were found not only in the white matter but also in the gray matter. Reverse transcriptase-polymerase chain reaction for MT3-MMP mRNA showed the same amount of expression in gray and white matters, while that for gelatinase A and MT1-MMP mRNA expressed much higher in the white matter than in the gray matter. These results suggest that MT3-MMP may play a role on Microglial cells, although its role may be different from MT1-MMP in the brain

  398. Zambenedetti P, Giordano R, Zatta P (1998) Histochemical localization of glycoconjugates on Microglial cells in Alzheimer's disease brain samples by using Abrus precatorius, Maackia amurensis, Momordica charantia, and Sambucus nigra lectins. Exp.Neurol. 153:167-171
    Abstract: Four lectins (Abrus precatorius (APA), Maackia amurensis (MAA), Momordica charantia (MCA) and Sambucus nigra (SNA)) have been used to identify glycohistochemically the Microglial cells (MGC) activation in autoptic brain samples from Alzheimer's disease (AD) subjects. Three of these lectins (APA, MAA and MCA) have utilized as Microglial cell markers for the first time. The identification of new markers for the study of MGC is very important to better understand the role of these type of cells in the metabolic/dismetabolic control of betaA4 in AD which still represents a vexata questio

  399. Aisen PS (1997) Inflammation and Alzheimer's disease: mechanisms and therapeutic strategies. Gerontology 43:143-149
    Abstract: Inflammatory mechanisms in the brain may contribute to the neurodegenerative process in Alzheimer's disease. The cerebral acute-phase response mediated by inflammatory cytokines, the complement cascade, and the accumulation of activated Microglial cells are appropriate targets for anti-inflammatory intervention. Pilot studies showed that tolerable doses of prednisone suppress the peripheral acute-phase response in Alzheimer's disease, and a multicenter therapeutic trial of prednisone is in progress. Two other anti-inflammatory drugs, hydroxychloroquine and colchicine, are also under investigation

  400. Banati RB (1997) The immune response in the Alzheimer's disease brain. Biochem.Soc.Trans. 25:683-685

  401. Barger SW, Harmon AD (1997) Microglial activation by Alzheimer amyloid precursor protein and modulation by apolipoprotein E. Nature 388:878-881
    Abstract: A role for beta-amyloid precursor protein (beta-APP) in the development of Alzheimer's disease has been indicated by genetics, and many conditions in which beta-APP is raised have been associated with an increased risk of Alzheimer's disease or an Alzheimer's-like pathology. Inflammatory events may also contribute to Alzheimer's disease. Here we investigate whether a secreted derivative of beta-APP (sAPP-alpha) can induce inflammatory reactions in Microglia, which are brain cells of monocytic lineage. We found that treatment with sAPP-alpha increased markers of activation in Microglia and enhanced their production of neurotoxins. The ability of sAPP-alpha to activate Microglia was blocked by prior incubation of the protein with apolipoprotein E3 but not apolipoprotein E4, a variant associated with an increased risk for Alzheimer's. A product of amyloidogenic beta-APP processing (sAPP-beta) also activated Microglia. Because sAPP-beta is deficient in the neuroprotective activity shown by sAPP-alpha, our results indicate that increased amyloidogenic processing could adversely affect the balance of sAPP activities that determine neuronal viability

  402. Bosman GJ, Renkawek K, Van Workum FP, Bartholomeus IG, De Grip WJ (1997) Involvement of neuronal anion exchange proteins in cell death in Alzheimer's disease. Gerontology 43:67-78
    Abstract: Anion exchange (AE) proteins are present in human neurons in the brain. Immunohistochemical data indicate that their apparent expression level increases with age, and especially with degeneration in Alzheimer's disease-affected brain areas. The increase in immunoreactivity is probably caused by changes in AE structure that lead to an increased accessibility of hitherto hidden epitopes. These epitopes correspond to regions in the membrane domain that are involved in generation of senescent cell-specific antigen from AE1 in aging erythrocytes. Elucidation of the molecular nature of these changes and the underlying mechanisms, will lead to insight in the processes that govern aging- and degeneration-associated perturbation of membrane integrity. AE-mediated chloride/bicarbonate exchange is a major component in the regulation of intracellular pH. The functional consequences of changes in AE structure may range from acidosis, disturbance of cytoskeleton integrity, and untimely or impaired recognition of cells by components of the immune system, such as Microglia. A molecular and physiological description of these changes will establish AE proteins as valuable tools in elucidating the processes of normal aging, and the disturbances in aging-related diseases such as Alzheimer's disease

  403. Dickson DW (1997) The pathogenesis of senile plaques. J.Neuropathol.Exp.Neurol. 56:321-339
    Abstract: Senile plaques (SP) are complicated lesions composed of diverse amyloid peptides and associated molecules, degenerating neuronal processes,a nd reactive glia. Evidence suggests that diffuse, neurocentric amyloid deposits evolve over time with formation of discrete niduses that eventually become neuritic SP. The evidence for differential amyloid precursor protein metabolism that may favor deposition of A beta 17-42 in this early, possibly aging-related lesion is discussed. This latter molecule, also known as P3, may represent a benign form of amyloid, since it lacks domains associated with activation and recruitment of glia to SP. Subsequent to deposition of A beta 1-42 and then growth of the amyloid with precipitation of soluble A beta 1-40, in an Alzheimer disease-specific process, SP increasingly become associated with activated Microglia and reactive astrocytes. In response to interaction with amyloid peptides and possibly glycated proteins, Microglia and astrocytes produce a number of molecules that may be locally toxic to neuronal processes in the vicinity of SP, including cytokines, reactive oxygen and nitrogen intermediates, and proteases. They also produce factors that lead to their reciprocal activation and growth, which potentiate a local inflammatory cascade. Paired helical filament- (PHF) type neurites appear to be associated with SP only in so far as neurofibrillary degeneration has progressed to affect neurons in those regions where the plaque forms. Thus, PHF-type neurites are readily apparent in SP in the amygdala at an early stage, while they are late in primary cortices and never detected in cerebellar plaques; where only dystrophic neurites are detected. If the various stages of SP pathogenesis can be further clarified, it may be possible to develop rational approaches to therapy directed at site-, cell type-, and stage-specific interventions. Although controlling the local inflammatory microenvironment of SP may hold promise for slowing lesion pathogenesis, it still remains a fundamental challenge to determine the mechanism of neurodegeneration that results in widespread neurofibrillary degeneration and eventual synaptic and neuronal loss, which is considered to be the proximate cause of the clinical dementia syndrome

  404. DiPatre PL, Gelman BB (1997) Microglial cell activation in aging and Alzheimer disease: partial linkage with neurofibrillary tangle burden in the hippocampus. J.Neuropathol.Exp.Neurol. 56:143-149
    Abstract: Microglial cells are the main component of the brain's resident immune system and are activated in Alzheimer disease (AD). We quantified the density of activated Microglial cells (AMG) in 8 sectors of human hippocampus to determine if their density is correlated with senile plaque (SP) and neurofibrillary tangle (NFT) formation. Ferritin-stained Microglia, Bielschowsky-stained neuritic plaques, and perikarya containing NFTs were counted in 8 young adults, 9 nondemented elderly adults, and 9 demented patients with AD. Microglial cell activation was moderately higher in elderly nondemented subjects. In AD there was a more striking activation in all sectors of the hippocampus. Most AMGs were distributed diffusely in neuropil and were not delimited to SPs or NFTs. Senile plaque counts were not linked with AMG counts within any sector. Neurofibrillary tangle counts were correlated significantly with AMG counts within one sector, the subiculum. When variations within and between sectors were factored out statistically, the burden of AMGs was correlated significantly with the burden of NFTs (r = 0.34; p < 0.005), but not SPs. Neuropathologic changes at the origin of the perforant pathway were correlated significantly with orthograde Microglial cell activation in the termination field. These observations show that correlations between Microglial cell activation and pathologic features of AD are only rarely significant. When significant linkage was present, it involved NFTs and not SPs, and depended on which sector of hippocampus was examined

  405. Drache B, Diehl GE, Beyreuther K, Perlmutter LS, Konig G (1997) Bcl-xl-specific antibody labels activated Microglia associated with Alzheimer's disease and other pathological states. J.Neurosci.Res. 47:98-108
    Abstract: This report describes the production of a monoclonal antibody raised against Bcl-xl, and includes an initial study of bcl-xl expression in neuropathology including Alzheimer's disease (AD). Bcl-xl is a potent apoptotic inhibitor and is known to be the predominant Bcl-x isoform in brain. To examine the expression of bcl-xl in aged brain and neurodegenerative disease, we raised a Bcl-xl-specific monoclonal antibody. In aged human brain, the highest bcl-xl expression was observed in cerebellum. By immunohistochemistry, significant bcl-xl expression was detected in reactive Microglia of patients with AD and other neurological diseases such as progressive supranuclear palsy. Bcl-xl-positive Microglia frequently colocalized with beta-amyloid plaques in AD and with activated astrocytes in non-AD and AD brains, suggesting a general role for Bcl-xl in regions of pathology. High levels of Bcl-xl protein might render Microglia more resistant to cytotoxic environments such as areas of neurodegeneration and astrogliosis

  406. Du YS, Zhu H, Fu J, Yan SF, Roher A, Tourtellotte WW, Rajavashisth T, Chen X, Godman GC, Stern D, Schmidt AM (1997) Amyloid-beta peptide-receptor for advanced glycation endproduct interaction elicits neuronal expression of macrophage-colony stimulating factor: a proinflammatory pathway in Alzheimer disease. Proc.Natl.Acad.Sci.U.S.A 94:5296-5301
    Abstract: In Alzheimer disease (AD), neurons are thought to be subjected to the deleterious cytotoxic effects of activated Microglia. We demonstrate that binding of amyloid-beta peptide (Abeta) to neuronal Receptor for Advanced Glycation Endproduct (RAGE), a cell surface receptor for Abeta, induces macrophage-colony stimulating factor (M-CSF) by an oxidant sensitive, nuclear factor kappaB-dependent pathway. AD brain shows increased neuronal expression of M-CSF in proximity to Abeta deposits, and in cerebrospinal fluid from AD patients there was approximately 5-fold increased M-CSF antigen (P < 0.01), compared with age-matched controls. M-CSF released by Abeta-stimulated neurons interacts with its cognate receptor, c-fms, on Microglia, thereby triggering chemotaxis, cell proliferation, increased expression of the macrophage scavenger receptor and apolipoprotein E, and enhanced survival of Microglia exposed to Abeta, consistent with pathologic findings in AD. These data delineate an inflammatory pathway triggered by engagement of Abeta on neuronal RAGE. We suggest that M-CSF, thus generated, contributes to the pathogenesis of AD, and that M-CSF in cerebrospinal fluid might provide a means for monitoring neuronal perturbation at an early stage in AD

  407. Giulian D (1997) Immune responses and dementia. Ann.N.Y.Acad.Sci. 835:91-110

  408. He J, Chen Y, Farzan M, Choe H, Ohagen A, Gartner S, Busciglio J, Yang X, Hofmann W, Newman W, Mackay CR, Sodroski J, Gabuzda D (1997) CCR3 and CCR5 are co-receptors for HIV-1 infection of Microglia. Nature 385:645-649
    Abstract: Several members of the chemokine receptor family are used together with CD4 for HIV-1 entry into target cells. T cell line-tropic (T-tropic) HIV-1 viruses use the chemokine receptor CXCR4 as a co-receptor, whereas macrophage-tropic (M-tropic) primary viruses use CCR5 (refs 2-6). Individuals with defective CCR5 alleles exhibit resistance to HIV-1 infection, suggesting that CCR5 has an important role in vivo in HIV-1 replication. A subset of primary viruses can use CCR3 as well as CCR5 as a co-receptor, but the in vivo contribution of CCR3 to HIV-1 infection and pathogenesis is unknown. HIV-1 infects the central nervous system (CNS) and causes the dementia associated with AIDS. Here we report that the major target cells for HIV-1 infection in the CNS, the Microglia, express both CCR3 and CCR5. The CCR3 ligand, eotaxin, and an anti-CCR3 antibody inhibited HIV-1 infection of Microglia, as did MIP-1beta, which is a CCR5 ligand. Our results suggest that both CCR3 and CCR5 promote efficient infection of the CNS by HIV-1

  409. Hollister RD, Xia M, McNamara MJ, Hyman BT (1997) Neuronal expression of class II major histocompatibility complex (HLA-DR) in 2 cases of Pick disease. Arch.Neurol. 54:243-248
    Abstract: BACKGROUND: Pick disease is a progressive form of dementia characterized by personality changes, speech disturbances, inattentiveness, and occasionally extrapyramidal phenomena. Although several variants have been recognized, the pathological profile of Pick disease includes focal frontotemporal atrophy, neuronal loss, astrocytosis, Pick bodies, and Pick cells. To date, little is known about the etiology of Pick disease. OBJECTIVE: To evaluate the possibility of inflammatory processes occurring in Pick disease pathophysiology. DESIGN: Immunohistochemistry for HLA-DR and related molecules was performed in brain tissue from individuals with Pick disease, Alzheimer disease, and diffuse Lewy body disease, as well as from neurologically normal controls. RESULTS: We report the unusual expression of the class II major histocompatibility complex protein Ia (HLA-DR) on neurons in 2 cases of Pick disease. In addition, both cases exhibited a dramatic Microglial response. Neuronal HLA-DR immunostaining was not observed in 12 other cases of Pick disease or cases of Alzheimer disease, cases of diffuse Lewy body disease, or in control cases run con-currently. In addition, the pattern of HLA-DR staining observed in Pick disease was confirmed with another monoclonal antibody to HLA-DR. Frequent in vitro inducers of HLA-DR expression and enhanced class I major histocompatibility expression, interferon gamma, and tumor necrosis factor alpha were not detected. CD4-positive T lymphocytes were also not present and class I major histocompatibility complex expression was not detected on neurons or glia from brain tissue with Pick disease. CONCLUSIONS: These results are the first to demonstrate class II major histocompatibility complex expression on neurons. Based on these preliminary results, we suggest that some cases of Pick disease may be complicated by or involve in inflammatory process

  410. Ishizuka K, Kimura T, Igata-yi R, Katsuragi S, Takamatsu J, Miyakawa T (1997) Identification of monocyte chemoattractant protein-1 in senile plaques and reactive Microglia of Alzheimer's disease. Psychiatry Clin.Neurosci. 51:135-138
    Abstract: It has been shown that human monocytes express monocyte chemoattractant protein-1 (MCP-1), an inflammatory factor, in response to non-fibrillar beta-amyloid protein. Reactive Microglia and inflammatory factors were reported to be present in beta-amyloid deposits (senile plaques) in Alzheimer's disease, suggesting the presence of MCP-1 in senile plaques. To address this issue, we examined MCP-1 immunoreactivity in senile plaques using a mouse monoclonal anti-MCP-1 antibody. Monocyte chemoattractant protein-1 was found immunohistochemically in mature senile plaques and reactive Microglia but not in immature senile plaques of brain tissues from five patients with Alzheimer's disease. These findings suggest that MCP-1-related inflammatory events induced by reactive Microglia contribute to the maturation of senile plaques

  411. Kawaguchi N, Yamada T, Yoshiyama Y (1997) [Expression of interferon-alpha mRNA in human brain tissues]. No To Shinkei 49:69-73
    Abstract: The localization of mRNA of interferon-alpha (IFNA21) was examined in human brain tissues from neurologically normal, Parkinson's and Alzheimer's disease (AD) cases, using an in situ hybridization method. In all cases, signals for the mRNA of IFNA21 were detected in the white matter Microglial cells. In AD brains, a few neurons in the parietal lobe were intensely labeled. These results suggest that one type of IFN-alpha protein is constitutively expressed in white matter Microglial cells, and that expression of IFN-alpha in neuronal cells may play some role in AD pathology

  412. Kim KS, Wegiel J, Sapienza V, Chen J, Hong H, Wisniewski HM (1997) Immunoreactivity of presenilin-1 in human, rat and mouse brain. Brain Res. 757:159-163
    Abstract: Monoclonal antibodies (mAbs) D3G6 and C8A5, specific for amino acid residues 160-168 of S182 protein, immunolabeled neurons, ependymal and choroid plexus cells, and myocytes in brain sections from normal subjects and people with Alzheimer disease or Down syndrome and in rats and mice. Oligodendroglia, Microglia, and the majority of astrocytes were negative. S182 protein or a fragment of the protein detected with these mAbs is not a constituent of amyloid-beta deposits or tangles

  413. Klegeris A, Walker DG, McGeer PL (1997) Interaction of Alzheimer beta-amyloid peptide with the human monocytic cell line THP-1 results in a protein kinase C-dependent secretion of tumor necrosis factor-alpha. Brain Res. 747:114-121
    Abstract: Immunological mechanisms, including stimulation of brain Microglia and elevation of various inflammatory cytokines, have been implicated in the pathogenesis of Alzheimer's disease, where accumulation of beta-amyloid peptide (A beta) is one of its main pathological features. In this study we investigated the interaction of human monocyte-like cells with synthetic beta-amyloid peptide A beta (1-40) and its subfragment A beta (25-35). THP-1 cells (a transformed human monocyte cell line) were used with or without prior differentiation by phorbol myristate acetate (PMA), and cell activation was assessed by the secretion of tumor necrosis factor-alpha (TNF-alpha). First, it was shown that THP-1 cells could be induced to secrete significant amounts of TNF-alpha by interleukin-1, lipopolysaccharide, interferon-gamma (IFN-gamma) and PMA alone or in combination with each other. Next it was shown that A beta (1-40) could also induce secretion of TNF-alpha by THP-1 cells, but the effect was diminished when this peptide was applied in combination with IFN-gamma. The A beta subfragment A beta (25-35) was ineffective in inducing TNF-alpha production. The cellular action of A beta (1-40) appears to involve protein kinase C since pretreatment of THP-1 cells by PMA or the protein kinase C inhibitor H-7 diminished the cellular response to A beta (1-40). Identification of the pathway by which extracellular A beta activates the intracellular PKC-dependent secretion of TNF-alpha may help in developing new therapeutic strategies for Alzheimer's disease

  414. Larner AJ (1997) The cerebellum in Alzheimer's disease. Dement.Geriatr.Cogn Disord. 8:203-209
    Abstract: The cerebellum is a relatively neglected area of the Alzheimer's disease (AD) brain, probably because it was formerly thought to be spared by the disease. However, a number of pathological changes have now been revealed in the AD cerebellum, principally by immunocytochemical studies, including widespread deposits of diffuse amyloid, ubiquitin-immunoreactive dystrophic neurites, and increased Microglia, but tau-immunoreactive neurofibrillary tangles have not been seen. Although the observed changes may be merely epiphenomenal to the pathological processes occurring in the AD neocortex and hippocampus, the morphological and immunocytochemical differences between AD cerebral cortex and cerebellar cortex may nonetheless give insights into the molecular factors involved in the development of the neuropathological lesions of AD brain

  415. LeVine SM (1997) Iron deposits in multiple sclerosis and Alzheimer's disease brains. Brain Res. 760:298-303
    Abstract: Iron may contribute to the pathogenesis of neurological diseases by promoting oxidative damage. The localization of iron in multiple sclerosis (MS) and Alzheimer's disease (AD) brains was investigated to further the understanding of its pathogenic role in these disease states. Earlier studies, utilizing a standard Perls' stain, yielded conflicting reports regarding the distribution of iron deposits in MS brains, and a previous study on AD brains utilized a diaminobenzidine (DAB) enhanced version of this stain. In the present study, a modified version of the DAB-enhanced stain was used; it utilizes sodium borohydride, proteinase K, Triton X-100 and xylenes to increase the accessibility of tissue iron to histochemical reagents. This modified method can reveal iron deposits that are missed by the Perls' or DAB-enhanced Perls' stains. In addition to its normal deposition in oligodendrocytes and myelin, iron was detected in reactive Microglia, ameboid Microglia and macrophages in MS brains. In AD brains, three types of plaques were stained: dense core, clear core and amorphous plaques. Punctate staining was also observed in neurons in the corticies of AD brains. The structure accounting for punctate labeling may be damaged mitochondria, lipofuscin or amyloid deposits. Dense core plaques, clear plaques and punctate labeling were not detected in the previous AD study which utilized only the DAB-enhanced Perls' stain. The labeling of these additional structures illustrates the benefit of the modified method. In summary, the localization of iron deposition in MS and AD brains indicates potential sites where iron could promote oxidative damage in these disease states

  416. Little SP, Dixon EP, Norris F, Buckley W, Becker GW, Johnson M, Dobbins JR, Wyrick T, Miller JR, MacKellar W, Hepburn D, Corvalan J, McClure D, Liu X, Stephenson D, Clemens J, Johnstone EM (1997) Zyme, a novel and potentially amyloidogenic enzyme cDNA isolated from Alzheimer's disease brain. J.Biol.Chem. 272:25135-25142
    Abstract: The deposition of the beta amyloid peptide in neuritic plaques and cerebral blood vessels is a hallmark of Alzheimer's disease (AD) pathology. The major component of the amyloid deposit is a 4.2-kDa polypeptide termed amyloid beta-protein of 39-43 residues, which is derived from processing of a larger amyloid precursor protein (APP). It is hypothesized that a chymotrypsin-like enzyme is involved in the processing of APP. We have discovered a new serine protease from the AD brain by polymerase chain reaction amplification of DNA sequences representing active site homologous regions of chymotrypsin-like enzymes. A cDNA clone was identified as one out of one million that encodes Zyme, a serine protease. Messenger RNA encoding Zyme can be detected in some mammalian species but not in mice, rats, or hamster. Zyme is expressed predominantly in brain, kidney, and salivary gland. Zyme mRNA cannot be detected in fetal brain but is seen in adult brain. The Zyme gene maps to chromosome 19q13.3, a region which shows genetic linkage with late onset familial Alzheimer's disease. When Zyme cDNA is co-expressed with the APP cDNA in 293 (human embryonic kidney) cells, amyloidogenic fragments are detected using C-terminal antibody to APP. These co-transfected cells release an abundance of truncated amyloid beta-protein peptide and shows a reduction of residues 17-42 of Abeta (P3) peptide. Zyme is immunolocalized to perivascular cells in monkey cortex and the AD brain. In addition, Zyme is localized to Microglial cells in our AD brain sample. The amyloidogenic potential and localization in brain may indicate a role for this protease in amyloid precursor processing and AD

  417. Luft FC (1997) Alzheimer's disease, blood lipids, and heart disease: what are the interrelationships? J.Mol.Med. 75:73-74

  418. Maat-Schieman ML, van Duinen SG, Rozemuller AJ, Haan J, Roos RA (1997) Association of vascular amyloid beta and cells of the mononuclear phagocyte system in hereditary cerebral hemorrhage with amyloidosis (Dutch) and Alzheimer disease. J.Neuropathol.Exp.Neurol. 56:273-284
    Abstract: Arterial and arteriolar amyloid-beta (A beta) deposition in hereditary cerebral hemorrhage with amyloidosis (Dutch) (HCHWA-D) and Alzheimer disease (AD) cerebral amyloid angiopathy (CAA) were studied as to morphology, extent, and association with mononuclear phagocyte system (MPS) cells using A beta, a-smooth muscle actin, and monocyte/macrophage marker (HLA-DR, CD68, CD11c, CD45) immunohistochemistry. The HCHWA-D/AD arterial/arteriolar media showed compact A beta deposits, first appearing at the media/adventitia junction, and concomitant smooth muscle loss. Only HCHWA-D CAA featured (a) severe involvement of larger arteries and (b) arterioles showing a single or double ring of radial A beta surrounding compact A beta. Radial A beta appeared to develop at the media/adventitia junction. Monocyte/macrophage marker-positive foci/cells co-localized with HCHWA-D arterial A beta. Focal HLA-DR/CD11c positivity was observed at the media/adventitia junction of AD/HCHWA-D arteries in the absence of local A beta, but not in controls. Monocyte/macrophage marker positivity co-localizing with radial A beta appeared continuous with perivascular cells and Microglia clustering perivascularly. These results suggest that (a) MPS cells are topographically associated with HCHWA-D arterial A beta and radial arteriolar A beta, and (b) HLA-DR/CD11c immunoreactivity may appear at the media/adventitia junction prior to A beta. The latter finding and the assumed formation of radial A beta at the media/adventitia junction may relate to involvement of the abluminal basement membrane in CAA pathogenesis. The role of MPS cells in this process remains to be established

  419. Marcusson J, Rother M, Kittner B, Rossner M, Smith RJ, Babic T, Folnegovic-Smalc V, Moller HJ, Labs KH (1997) A 12-month, randomized, placebo-controlled trial of propentofylline (HWA 285) in patients with dementia according to DSM III-R. The European Propentofylline Study Group. Dement.Geriatr.Cogn Disord. 8:320-328
    Abstract: Alzheimer's disease (AD) and vascular dementia (VaD) share several features such as overactivation of Microglial cells, damage induced by free radicals, glutamate and calcium overload. Propentofylline (HWA 285) has shown beneficial effects on all of these common elements, thus favouring its use in both subtypes of dementia. In a multinational, randomized, 12-month, double-blind, parallel-group study 260 out-patients with mild to moderate AD or VaD received 300 mg propentofylline (n = 129) or placebo (n = 131) three times daily 1 h before meals. The efficacy was tested at four independent rater levels (physician, psychologist, relative and patient) with assessments covering three major domains of dementia (global function, cognitive function and activities of daily living). After 12 months, the total patient population showed statistically significant treatment differences in favour of propentofylline for the global measures of dementia (Gottfries-Brane-Steen scale, GBS, p = 0.001; Clinical Global Impressions, CGI, item I: p = 0.004, item II: p = 0.072) as well as for the cognitive measures (Syndrome Short Test, SKT, p = 0.002) and Mini-Mental State Examination (p = 0.001). The activities of daily living also showed a significant treatment difference in favour of propentofylline (p = 0.002). No significant treatment differences were found for rating scales performed by the patients. At month 12, VaD patients showed treatment differences in favour of propentofylline for the GBS total score (p = 0.006), CGI item I (p = 0.004), GGI item II (p = 0.044) and SKT (p = 0.028). Treatment differences for AD patients were all in favour of propentofylline and reached statistical significance for the SKT (p = 0.018). Propentofylline showed a good safety profile with respect to adverse events, vital signs, ECG and laboratory changes

  420. Mattson MP, Barger SW, Furukawa K, Bruce AJ, Wyss-Coray T, Mark RJ, Mucke L (1997) Cellular signaling roles of TGF beta, TNF alpha and beta APP in brain injury responses and Alzheimer's disease. Brain Res.Brain Res.Rev. 23:47-61
    Abstract: beta-Amyloid precursor protein (beta APP), transforming growth factor beta (TGF beta), and tumor necrosis factor-alpha (TNF alpha) are remarkably pleiotropic neural cytokines/neurotrophic factors that orchestrate intricate injury-related cellular and molecular interactions. The links between these three factors include: their responses to injury; their interactive effects on astrocytes, Microglia and neurons; their ability to induce cytoprotective responses in neurons; and their association with cytopathological alterations in Alzheimer's disease. Astrocytes and Microglia each produce and respond to TGF beta and TNF alpha in characteristic ways when the brain is injured. TGF beta, TNF alpha and secreted forms of beta APP (sAPP) can protect neurons against excitotoxic, metabolic and oxidative insults and may thereby serve neuroprotective roles. On the other hand, under certain conditions TNF alpha and the fibrillogenic amyloid beta-peptide (A beta) derivative of beta APP can promote damage of neuronal and glial cells, and may play roles in neurodegenerative disorders. Studies of genetically manipulated mice in which TGF beta, TNF alpha or beta APP ligand or receptor levels are altered suggest important roles for each factor in cellular responses to brain injury and indicate that mediators of neural injury responses also have the potential to enhance amyloidogenesis and/or to interfere with neuroregeneration if expressed at abnormal levels or modified by strategic point mutations. Recent studies have elucidated signal transduction pathways of TGF beta (serine/threonine kinase cascades), TNF alpha (p55 receptor linked to a sphingomyelin-ceramide-NF kappa B pathway), and secreted forms of beta APP (sAPP; receptor guanylate cyclase-cGMP-cGMP-dependent kinase-K+ channel activation). Knowledge of these signaling pathways is revealing novel molecular targets on which to focus neuroprotective therapeutic strategies in disorders ranging from stroke to Alzheimer's disease

  421. McGeer EG, McGeer PL (1997) The role of the immune system in neurodegenerative disorders. Mov Disord. 12:855-858

  422. McRae A, Dahlstrom A, Ling EA (1997) Microglial in neurodegenerative disorders: emphasis on Alzheimer's disease. Gerontology 43:95-108
    Abstract: Hallmark lesions of Alzheimer's disease (AD) are filled with reactive immunocompetent Microglia, suggesting that immunological aberrations may participate in the pathophysiology of this disorder. If immune-mediated processes are closely linked to neuronal breakdown it would be of importance to have a reliable means to detect these processes. Cerebrospinal fluid Microglial antibodies found mainly in AD patients are discussed as such potential sources. These antibodies recognize Microglia in the developing rat brain, in neuronal cultures and on AD cortical biopsies. Treatment aimed at downregulating Microglial is discussed and may have therapeutic significance for AD patients. Largely this review presents current opinions which support the concept that inflammation and similar immune mechanisms need to be considered as participating in AD pathogenesis

  423. Mori M, Yoshiyama Y, Waragai M, Yoshikawa K, Yamada T (1997) [Distribution of amyloid precursor protein mRNA in Alzheimer brain tissues]. No To Shinkei 49:804-808
    Abstract: This study aimed to provide clear data on the localization of the mRNA for the amyloid precursor protein (APP) in human brain. It is known to occur in neurons but the possible localization in other type of brain cells is controversial among several authors. A cDNA probe constructed by polymerase chain reaction for APP, which was not specific for a particular isoform, gave punctate staining and showed a clear localization not only in neurons but in astrocytes in all brains, as well as in the reactive Microglia associated with senile plaques in Alzheimer disease. A cRNA probe gave more diffuse staining of neurons and glia

  424. Mrak RE, Griffin WS (1997) The role of chronic self-propagating glial responses in neurodegeneration: implications for long-lived survivors of human immunodeficiency virus. J.Neurovirol. 3:241-246
    Abstract: Within the last decade there has arisen increasing appreciation of the role of glia-derived immune and neurotrophic cytokines, especially Microglia-derived interleukin-1 and astrocyte-derived S100beta, in the pathophysiology of Alzheimer's disease and of neurodegeneration in general. Available evidence now suggests that these neurotrophic and immune cytokines, produced in response to neuronal cell dysfunction or death, may elicit cellular and molecular responses resulting in further activation of glia and glial cytokine secretion, producing a cytokine cycle. In conditions characterized by chronic glial activation this cycle becomes self propagating, promoting further neurodegeneration and subsequent further induction of glial cell activation with production of cytokines. In Alzheimer's disease, for instance, such self-propagation is essential to the progressive accumulation of neuropathological changes that underlie progressive dementia. Conditions that predispose one to Alzheimer-type 'senile' neuropathological changes, and to later development of Alzheimer's disease, also exhibit glial activation and overexpression of glial cytokines, providing further evidence of a pathogenic role for glial activation and cytokine cycle elements in the initiation and propagation of Alzheimer lesions. HIV produces a chronic viral infection of the central nervous system that has been associated with chronic glial activation and overexpression of some of the same cytokines that have been implicated in Alzheimer pathogenesis. These observations, together with established functions of cytokine cycle elements, suggest that chronic HIV infection in sufficiently long-lived HIV-infected individuals might confer additional risk for later development of Alzheimer's disease

  425. Nalbantoglu J, Tirado-Santiago G, Lahsaini A, Poirier J, Goncalves O, Verge G, Momoli F, Welner SA, Massicotte G, Julien JP, Shapiro ML (1997) Impaired learning and LTP in mice expressing the carboxy terminus of the Alzheimer amyloid precursor protein. Nature 387:500-505
    Abstract: Proteolytic processing of amyloid precursor protein (APP) through an endosomal/lysosomal pathway generates carboxy-terminal polypeptides that contain an intact beta-amyloid domain. Cleavage by as-yet unidentified proteases releases the beta-amyloid peptide in soluble form. In Alzheimer's disease, aggregated beta-amyloid is deposited in extracellular neuritic plaques. Although most of the molecular mechanisms involving beta-amyloid and APP in the aetiology of Alzheimer's disease are still unclear, changes in APP metabolism may be important in the pathogenesis of the disease. Here we show that transgenic mice expressing the amyloidogenic carboxy-terminal 104 amino acids of APP develop, with ageing, extracellular beta-amyloid immunoreactivity, increased gliosis and Microglial reactivity, as well as cell loss in the CA1 region of the hippocampus. Adult transgenic mice demonstrate spatial-learning deficits in the Morris water maze and in maintenance of long-term potentiation (LTP). Our results indicate that alterations in the processing of APP may have considerable physiological effects on synaptic plasticity

  426. Paresce DM, Chung H, Maxfield FR (1997) Slow degradation of aggregates of the Alzheimer's disease amyloid beta-protein by Microglial cells. J.Biol.Chem. 272:29390-29397
    Abstract: Microglia are immune system cells associated with senile plaques containing beta-amyloid (Abeta) in Alzheimer's disease. Although Microglia are an integral part of senile plaques, their role in the development of Alzheimer's disease is not known. Because Microglia are phagocytic cells, it has been suggested that Microglia may function as plaque-attacking scavenger cells. Microglia bind and internalize microaggregates of Abeta that resemble those present in dense Alzheimer's disease plaques. In this study, we compared the degradation by Microglia of Abeta microaggregates with the degradation of two other proteins, acetylated low density lipoprotein and alpha2-macroglobulin. We found that the majority of the internalized Abeta in microaggregates was undegraded 72 h after uptake, whereas 70-80% of internalized acetylated low density lipoprotein or alpha2-macroglobulin was degraded and released from cells in trichloroacetic acid-soluble form after 4 h. In the continued presence of fluorescent Abeta microaggregates for 4 days, Microglia took up huge amounts of Abeta and became engorged with undigested material. These data suggest that Microglia can slowly degrade limited amounts of Abeta plaque material, but the degradation mechanisms can be overwhelmed by larger amounts of Abeta

  427. Passani LA, Vonsattel JP, Coyle JT (1997) Distribution of N-acetylaspartylglutamate immunoreactivity in human brain and its alteration in neurodegenerative disease. Brain Res. 772:9-22
    Abstract: The dipeptide N-acetylaspartylglutamate (NAAG) may be involved in the process of glutamatergic signaling by both acting at glutamate receptors and as a glutamate protransmitter. In the present study we determined the cellular localization and distribution of NAAG-like immunoreactivity (NAAG-LI) in normal human brain and in neurodegenerative disorders to ascertain the degree of NAAG's colocalization to putative glutamatergic pathways. Immunohistochemistry with an antibody against NAAG was performed on control, Huntington's disease (HD) and Alzheimer's disease (AD) human autopsy and biopsy brain sections from the cerebral cortex, hippocampus, amygdala, neostriatum, brainstem and spinal cord. In normal human brain, NAAG-LI was widespread localized to putative glutamatergic pyramidal neurons of the cerebral cortex and hippocampus. Punctate NAAG-LI was present in areas known to receive neuronal glutamatergic input, such as layer IV of the cerebral cortex, striatal neuropil, and the outer portion of the molecular layer of the hippocampal dentate gyrus. In the two pathologic brain regions examined, the HD neostriatum and the AD temporal cortex, we observed a widespread loss of NAAG-LI neurons. In addition NAAG-LI reactive Microglia surrounding plaques were seen in AD temporal cortex but not in the HD striatum. Our results suggest that NAAG is substantially localized to putative glutamatergic pathways in human brain and that NAAG-LI neurons are vulnerable to the neurodegenerative process in HD and AD

  428. Pratt BM, McPherson JM (1997) TGF-beta in the central nervous system: potential roles in ischemic injury and neurodegenerative diseases. Cytokine Growth Factor Rev. 8:267-292
    Abstract: The Transforming Growth Factor-betas (TGF-beta) are a group of multifunctional proteins whose cellular sites of production and action are widely distributed throughout the body, including the central nervous system (CNS). Within the CNS, various isoforms of TGF-beta are produced by both glial and neural cells. When evaluated in either cell culture or in vivo models, the various isoforms of TGF-beta have been shown to have potent effects on the proliferation, function, or survival of both neurons and all three glial cell types, astrocytes, Microglia and oligodendrocytes. TGF-beta has also been shown to play a role in several forms of acute CNS pathology including ischemia, excitotoxicity and several forms of neurodegenerative diseases including multiple sclerosis, Parkinson's disease, AIDS dementia and Alzheimer's disease

  429. Price DL, Wong PC, Borchelt DR, Pardo CA, Thinakaran G, Doan AP, Lee MK, Martin LJ, Sisodia SS (1997) Amyotrophic lateral sclerosis and Alzheimer disease. Lessons from model systems. Rev.Neurol.(Paris) 153:484-495
    Abstract: The human neurodegenerative diseases, including motor neuron disease and Alzheimer's disease (AD), are characterized by a selective involvement of certain regions of the brain/spinal cord and selected populations of neurons. Sporadic amyotrophic lateral sclerosis (ALS) is an age-associated disease with cytoskeletal abnormalities and death of motor neurons; familial ALS (FALS), an autosomal dominant disease linked to mutations in superoxide dismutase 1 (SOD1), is manifested by inclusions and degeneration of motor neurons. Autosomal dominant familial AD (FAD), linked to mutations in presenilin (PS1 and PS2) genes or the amyloid precursor protein (APP) gene, shows brain abnormalities (e.g., neurofibrillary tangles, deposits of .-amyloid A., and death of subsets of neurons) similar to those that occur in sporadic AD, the risk of which is enhanced by the presence of one or two copies of apolipoprotein E4 (apoE4) alleles. To examine the mechanisms of these diseases, investigators have used a variety of animal models, including experimentally produced, spontaneously occurring, or genetically engineered models of disease. Studies of models of degeneration of motor neurons (axotomy) and cytoskeletal abnormalities seen in motor neuron disease (i.e., axonopathy induced by .,.'-iminodipropionitrile (IDPN), hereditary canine spinal muscular atrophy (HCSMA), and neurofilament NF transgenic Tg mice) have demonstrated that NF-filled swellings of axons are related to alterations in the biology of NF transport. Tg mice with SOD1 mutations, which develop the clinical features of FALS, show selective degeneration of motor neurons, which is attributed to the acquisition of toxic properties by mutant SOD1. Models of AD include: aged monkeys that show both cognitive/memory deficits and cellular abnormalities (amyloid deposition/cytoskeletal abnormalities of neurons) in cortex and hippocampus; and Tg mice that express mutant human FAD-linked genes (i.e., APP and PS1) and show increased levels of A.42, amyloid deposits, dystrophic neurites, and local responses of astrocytes and Microglia. This review discusses the behavioral/neuropathological features of AD, the results of investigations of mechanisms of disease in model systems, and potential utility of some of these models for testing new therapies

  430. Saitoh T, Kang D, Mallory M, DeTeresa R, Masliah E (1997) Glial cells in Alzheimer's disease: preferential effect of APOE risk on scattered Microglia. Gerontology 43:109-118
    Abstract: Reactive glial cells are consistently found in the brain tissue of Alzheimer's disease (AD) patients. Both clustered and scattered glial cells occur in AD brain. A number of clustered Microglial cells, but not astrocytes, had a positive correlation with neurite plaque numbers, suggesting that clustered micro-glial cells are uniquely associated with plaques whereas clustered astrocytes may have functions outside the plaques as well. APOE epsilon 4, the major genetic risk factor for AD, had a dose-dependent effect to increase the numbers of scattered Microglial cells whereas the APOE risk showed no correlation with any of the clustered glial cells or scattered astrocytes. These findings raise the possibility that the increased levels of scattered, but not clustered, Microglial cells are the immediate response to APOE risk and might be primarily involved in AD pathogenesis

  431. Sasaki A, Yamaguchi H, Ogawa A, Sugihara S, Nakazato Y (1997) Microglial activation in early stages of amyloid beta protein deposition. Acta Neuropathol.(Berl) 94:316-322
    Abstract: The present study was undertaken to investigate the relationship of Microglial activation to amyloid beta protein (A beta) deposition, particularly at the early stage. Using single and double immunostaining methods with a panel of Microglia markers and antibodies against A beta and amyloid beta protein precursor (APP), we examined the cerebrum and cerebella of both Alzheimer's disease (AD) and non-demented subjects obtained at autopsy. In nondemented, middle-aged subjects that had small amounts of cerebral A beta deposits, approximately 70% of the diffuse plaques contained ramified Microglia. However, no evidence of Microglial activation was found in diffuse plaques in any of the non-demented subjects. Dual immunostaining of sections of cerebral cortex using antibodies against A beta and major histocompatibility complex class II antigen showed that in AD subjects, approximately 20% of total diffuse plaques contained a few, activated Microglia. Most of these plaques were defined as a transitional from between diffuse and primitive plaques. Both primitive and classic plaques in the cerebral cortex of AD subjects consistently contained clusters of activated Microglia. Subpial A beta deposits without neuritic changes lacked Microglial activation. In the cerebellum, all of the diffuse plaques lacked Microglial activation, and activated Microglia in the compact plaques were not as hypertrophic as those in cerebral primitive/classic plaques. Our findings indicate that Microglial reactions are absent in the early stages of A beta deposition, and it occurs during the transition from diffuse to primitive plaques, when amounts of A beta deposits and the degree of neuritic changes increase

  432. Schubert P, Ogata T, Rudolphi K, Marchini C, McRae A, Ferroni S (1997) Support of homeostatic glial cell signaling: a novel therapeutic approach by propentofylline. Ann.N.Y.Acad.Sci. 826:337-347
    Abstract: A pathological glial cell activation, which forces Microglia to transform into immunocompetent cells with cytotoxic properties and astrocytes to "de-differentiate," presumably adds to neurodegenerative diseases. We examined the modulatory effect of adenosine on the Ca2+ and cAMP-dependent regulation of such reactive glial cell properties in culture and tested possibilities of pharmacologic reinforcement. A strengthening of the cAMP-signaling, as could be achieved by adenosine agonists via a Ca(2+)-dependent action, favored the differentiation of proliferating astrocytes and associated neuroprotective properties (ion homeostasis, formation of trophic factors). But potentially neurotoxic properties of Microglial cells were inhibited. Adenosine depressed their proliferation rate and transformation into macrophages, their particularly high formation of reactive oxygen intermediates and the release of the cytokine TNF-alpha. Similar effects were obtained with propentofylline, which acts as selective cAMP/cGMP phosphodiesterase inhibitor and also increases the effective concentration of adenosine by blocking its cellular reuptake. The recently observed induction of Microglial apoptosis by elevated extracellular adenosine levels may further contribute to limit secondary nerve cell damage related to a pathological glial cell activation

  433. Sheng JG, Mrak RE, Griffin WS (1997) Glial-neuronal interactions in Alzheimer disease: progressive association of IL-1alpha+ Microglia and S100beta+ astrocytes with neurofibrillary tangle stages. J.Neuropathol.Exp.Neurol. 56:285-290
    Abstract: Activated Microglia, overexpressing interleukin-1 (IL-1), and activated astrocytes, overexpressing S100beta, have been implicated in the formation and evolution of tau2-immunoreactive (tau2+) neuritic plaques in Alzheimer disease. In this study, we assessed the role of IL-1alpha+ Microglia and S100beta+ astrocytes in the pathogenesis of another cardinal histopathological feature of Alzheimer disease: tau2+ neurofibrillary tangles. Four distinct stages of neurofibrillary tangle formation were identified: neurons with granular perikaryal tau2 immunoreactivity (stage 0); fibrillar neuronal inclusions (stage 1); dense, neuronal soma-filling inclusions (stage 2); and acellular, fibrillar deposits (stage 3, "ghost tangles"). The numbers of tangles in randomly selected fields of parahippocampal cortex from 11 Alzheimer patients correlated with both the numbers of IL-1alpha+ Microglia and the numbers of S100beta+ astrocytes in these fields (r = 0.72, p < 0.02; r = 0.73, p = 0.01, respectively). There were progressive increases in frequency of association between tangle stages and both IL-1alpha+ Microglia and S100beta+ astrocytes: 48, 56, 67, and 92% of stage 0-3 tangles, respectively, had associated IL-1alpha+ Microglia; and 21, 37, 55, and 91% of stage 0-3 tangles had associated S100beta+ astrocytes. This progressive association of activated IL-1alpha+ Microglia and activated S100beta+ astrocytes with tau2+ tangle stages suggests a role for glial-neuronal interactions in the degeneration of tangle-bearing neurons in Alzheimer disease

  434. Sheng JG, Mrak RE, Griffin WS (1997) Neuritic plaque evolution in Alzheimer's disease is accompanied by transition of activated Microglia from primed to enlarged to phagocytic forms. Acta Neuropathol.(Berl) 94:1-5
    Abstract: Activated Microglia, overexpressing the potent neuroactive cytokine interleukin-1, have been implicated as a driving force in the evolution of diffuse amyloid deposits into diagnostic neuritic plaques in Alzheimer's disease. To evaluate this role further, we used double-label immunohistochemistry to classify and quantify plaque-associated and non-plaque-associated activated interleukin-1-immunoreactive Microglia in parahippocampal tissue from 11 patients with Alzheimer's disease. These activated Microglia were subclassified as primed (only slightly enlarged), enlarged, or phagocytic (enlarged with heterogeneous cytoplasmic contents). We further determined the distribution of these Microglial subtypes among four defined plaque types. Most (84%) primed Microglia were not plaque associated, although 13% were present in diffuse non-neuritic plaques and 3% were present in diffuse neuritic plaques. In contrast, most enlarged (55%) and phagocytic (91%) Microglia were plaque associated. Of plaque-associated enlarged Microglia, most (71%) were found in diffuse neuritic plaques with the remainder evenly distributed between diffuse non-neuritic and dense-core neuritic plaques (15% each). Of plaque-associated phagocytic Microglia, a few were present in diffuse non-neuritic plaques (5%), but most were found in diffuse neuritic plaques (62%) and dense-core neuritic plaques (33%). These findings show preferential association of primed Microglia with diffuse amyloid deposits and imply that Microglial transformation from primed, to enlarged, to phagocytic types occurs in concert with the evolution of amyloid plaques from diffuse amyloid deposits to the neuritic beta-amyloid plaque forms in Alzheimer's disease. Microglial phagocytic activity in neuritic plaques may reflect involvement in the processing of diffuse amyloid into condensed beta-amyloid, or in clearance of neuritic debris

  435. Shoham S, Ebstein RP (1997) The distribution of beta-amyloid precursor protein in rat cortex after systemic kainate-induced seizures. Exp.Neurol. 147:361-376
    Abstract: In the current study we employed immunohistochemical techniques to identify neuronal and glial cells in specific brain areas that modulate beta-amyloid precursor protein (betaAPP) synthesis following kainate-induced seizures. In addition, antibodies directed against the FOS protein, which is generated by activation of the immediate early gene c-fos and is temporally associated with ongoing seizure activity, were used to identify transneuronal pathways activated after kainate-induced seizures (KIS). It was therefore possible to correlate the appearance of activated neuronal pathways identified by FOS-like immunoreactivity (LI) and PAPP-LI in alternate sections. In addition, we employed immunohistochemical procedures to characterize morphological changes in neuronal and glial cells following kainate-induced seizures in both young and adult rats. Our results demonstrate a specific pattern of FOS-LI induced by kainate injection. In older animals FOS-LI spreads out from limbic cortical regions, including the piriform and entorhinal cortex, to other cortical regions, including the parietal and somatosensory cortices. Seizures were associated with decrease in neuronal betaAPP-LI in both young and adult rats, whereas glial betaAPP-LI markedly increased. The increase in betaAPP-LI glia was far more extensive in adult than in young rats and the anatomical distribution of betaAPP-LI glia was grossly correlated with FOS-LI. The spread of betaAPP-LI follows seizure-activated transsynaptic pathways. It is likely that the sequence of events following kainate injection is initially triggered by c-fos gene expression, which is rapidly followed by modulation of betaAPP synthesis in parallel to, or preceding, morphological changes of both Microglia and astrocytes. The present study, which extensively characterized early changes in c-fos expression and betaAPP-LI in glia following kainate-induced seizures, is a potentially useful animal model for the in vivo study of numerous facets of betaAPP synthesis and the possible role of such processes in Alzheimer's disease

  436. Streit WJ, Sparks DL (1997) Activation of Microglia in the brains of humans with heart disease and hypercholesterolemic rabbits. J.Mol.Med. 75:130-138
    Abstract: Activated Microglial cells are concentrated in senile plaques characteristic of Alzheimer's disease. Such accumulations of activated Microglia may contribute towards neurodegeneration via production of cytokines and free radicals. Studies suggesting a link between Alzheimer's disease and heart disease led us to study Microglia immunohistochemically, using monoclonal antibody LN-3, in age-matched nondemented humans with and without heart disease. Using a qualitative staging system for assessing morphological changes occurring in Microglia, we found higher Microglial activation in the brains of subjects with heart disease than in those without it. Lectin histochemical examination of brains from rabbits maintained on a high-cholesterol diet also revealed increased Microglial activation and leukocyte infiltration. Collectively our observations from humans and rabbits suggest that hypercholesterolemia and heart disease accelerate brain aging, and that the formation of senile plaques may be the end result of progressive Microglial activation that occurs with aging

  437. Su JH, Deng G, Cotman CW (1997) Bax protein expression is increased in Alzheimer's brain: correlations with DNA damage, Bcl-2 expression, and brain pathology. J.Neuropathol.Exp.Neurol. 56:86-93
    Abstract: We have shown that many neurons in Alzheimer's disease (AD) exhibit terminal deoxynucleotidyl transferase (TdT) labeling for DNA strand breaks, and upregulation of Bcl-2 is associated with neurons exhibiting nuclear DNA fragmentation, while downregulation of Bcl-2 is associated with tangle-bearing neurons in AD brains. Consequently, we examined the expression of bcl-associated X (Bax) protein in AD brain. Immunoreactivity for Bax was seen in neurons and Microglia of the hippocampal formation, and was elevated in the majority of AD cases as compared to control cases. Interestingly, 3 transitional cases, which had mild degeneration changes, exhibited relatively high levels of Bax immunoreactivity. Most Bax-positive neurons showed either TdT-labeled nuclei or Bcl-2 immunoreactivity. Although Bax immunoreactivity was detected within most early tangle-bearing neurons, many Bax-positive neurons did not colocalize with later-stage tangle-bearing neurons. In regions containing relatively few tangles in mild AD brains, many TdT-labeled neurons were immunolabeled with Bax antibody and most of them lacked evidence of neurofibrillary changes. These findings suggest that Bax may contribute to neuronal cell death in AD. Furthermore, DNA damage and the upregulation of Bax appear to precede tangle formation or may represent an alternative pathway of cell death in AD

  438. Sugaya K, Reeves M, McKinney M (1997) Topographic associations between DNA fragmentation and Alzheimer's disease neuropathology in the hippocampus. Neurochem.Int. 31:275-281
    Abstract: To identify whether the process of apoptosis bears a topographic relationship to selected aspects of Alzheimer's disease (AD) pathology, we used an in situ nick translation method (TUNEL) to map DNA fragmentation in hippocampal sections immunostained for abnormally phosphorylated tau, which exists in the neurofibrillary tangles (NFTs) and in the dystrophic neurites associated with senile plaques. To ascertain associations of DNA fragmentation with glia, TUNEL was combined with immunohistochemistry for the astrocyte marker, glial fibrillary acidic protein (GFAP), or the Microglial antigen OX-42. Consistent with previous reports, the incidence of putative DNA fragmentation detected by TUNEL was much higher in the AD brain, compared to non-demented subjects. While most TUNEL-positive cells did not exhibit any systematic topographic relationship to senile plaques, which were visualized by immunostain of abnormally phosphorylated tau for dystrophic neurites, DNA fragmentation was found frequently within cells containing NFTs. In hippocampal sections prepared to visualize glia, DNA fragmentation was not observed in GFAP-positive astrocytes, but some OX-42-positive Microglia exhibited TUNEL signals. Other TUNEL-positive cells were found frequently in proximity to glia. The data suggest that cells compromised by the deposition of NFTs are prone to initiate the process of apoptosis. Furthermore, some glial populations appear to be apoptotic in the AD brain

  439. Thal DR, Schober R, Birkenmeier G (1997) The subunits of alpha2-macroglobulin receptor/low density lipoprotein receptor-related protein, native and transformed alpha2-macroglobulin and interleukin 6 in Alzheimer's disease. Brain Res. 777:223-227
    Abstract: To explore the role of alpha2-macroglobulin receptor/low density lipoprotein receptor-related protein (alpha2M-R/LRP) and its ligands in the pathogenesis of Alzheimer's disease (AD), antibodies were raised against its alpha- and beta-subunits and their expression pattern in the CNS in AD and control cases was correlated with that of native and transformed alpha2-macroglobulin (alpha2M) and interleukin 6 (IL-6). The transmembranous beta-subunit of alpha2M-R/LRP and transformed alpha2M were found in plaque cores in AD. Extramembranous alpha-subunit and native alpha2M immunoreactivities were localized in activated plaque-associated astrocytes and extracellularly in plaques. IL-6 immunostaining was associated with neurofibrillary changes, and was also found extracellularly in the center of plaques and in Microglial cells. Our finding that plaque cores contain a second transmembranous protein fragment, the beta-subunit of alpha2 M-R/LRP, suggests ongoing membrane-protein degradation. By altering clearance and scavenger-like functions, fragmentation and breakdown of alpha2M-R/LRP may have an important role in extracellular amyloid deposition and the formation of neurofibrillary tangles in AD

  440. Tomimoto H, Akiguchi I, Wakita H, Suenaga T, Nakamura S, Kimura J (1997) Regressive changes of astroglia in white matter lesions in cerebrovascular disease and Alzheimer's disease patients. Acta Neuropathol.(Berl) 94:146-152
    Abstract: The pathogenesis of white matter lesions, which are frequently found in ischemic cerebrovascular disease and Alzheimer's disease, remains unclear. Using light and electron microscopic immunohistochemistry for glial fibrillary acidic protein (GFAP) as a marker, the present study focused on the role of astroglia which show characteristic morphological alterations. Of 29 brains of patients with cerebrovascular disease and Alzheimer's disease, 4 brains showed extensive swelling and vacuolation of white matter astroglia with their processes disintegrated and beaded (termed clasmatodendrosis). No such cells were observed in 6 control patients. Clasmatodendritic astroglia were not intensely eosinophilic using hematoxylin and eosin staining and included large lipophilic granules in their perikarya. These astroglia were immunoreactive for serum proteins such as immunoglobulins, fibrinogen and complement C3, C1q and C3d, as well as for proteins which are known to increase in reactive astroglia, such as vimentin, alpha-B crystallin, apolipoprotein-E and laminin. Double labeling for GFAP and Microglial cell markers indicated that these cells were of astroglial lineage. Immunoelectron microscopy for GFAP revealed that clasmatodendritic astroglia had condensed chromatin, lysosomes and large membrane-bound osmiophilic cytoplasmic inclusions, which corresponded to the lipophilic granules observed with light microscopy. These cytochemical features collectively suggest that clasmatodendritic astroglia incorporate edema fluid and phagocytose cellular debris, and eventually degenerate as a result of cerebral edema

  441. Tompkins MM, Basgall EJ, Zamrini E, Hill WD (1997) Apoptotic-like changes in Lewy-body-associated disorders and normal aging in substantia nigral neurons. Am.J.Pathol. 150:119-131
    Abstract: In Parkinson's disease and other Lewy-body-associated disorders, the substantia nigra pars compacta undergoes degeneration, but the mechanism of cell death has not been previously described. The substantia nigra of normal and Alzheimer's disease cases were compared with substantia nigra from patients with Lewy-body-associated disorders (Parkinson's disease, concomitant Alzheimer's/Parkinson's disease, and diffuse Lewy body disease) using in situ end labeling to detect fragmented DNA. In situ end-labeled neurons demonstrated changes resembling apoptosis: nuclear condensation, chromatin fragmentation, and formation of apoptotic-like bodies. Ultrastructural analysis confirmed nuclear condensation and formation of apoptotic-like bodies. Apoptotic-like changes were seen in the substantia nigra of both normal and diseased cases; concomitant Alzheimer's/Parkinson's disease and diffuse Lewy body disease cases had significantly higher amounts of apoptotic-like changes than normal controls or Alzheimer patients. The finding of neuronal death by apoptosis may have relevance for the development of new treatment strategies for Parkinson's disease and related disorders

  442. Uchihara T, Akiyama H, Kondo H, Ikeda K (1997) Activated Microglial cells are colocalized with perivascular deposits of amyloid-beta protein in Alzheimer's disease brain. Stroke 28:1948-1950
    Abstract: BACKGROUND AND PURPOSE: Microglial cells are present in the center of senile plaques (SPs) in Alzheimer's disease (AD) brain. Such a localization of Microglial cells suggests that they are involved in the deposition or the clearance of amyloid-beta protein (A beta) in the brain. We examined their association with another type of parenchymal A beta deposit, which is termed the perivascular deposits of A beta (PA beta). METHODS: Thick sections from AD brain were stained with a three-color immunofluorescence method that labeled A beta, activated Microglial cells, and vascular endothelial cells simultaneously. RESULTS: Three-dimensional observation under a laser scanning microscope confirmed that perivascular aggregates of activated Microglial cells were colocalized with PA beta. CONCLUSIONS: Microglia occur in association with both SPs and PA beta, suggesting that they play important roles in the metabolism of A beta in AD brain

  443. Van Dyke K (1997) The possible role of peroxynitrite in Alzheimer's disease: a simple hypothesis that could be tested more thoroughly. Med.Hypotheses 48:375-380
    Abstract: Alzheimer's disease is characterized by the development of a degenerative condition in the elderly, associated with dementia. Upon pathological examination, cerebral amyloid plaques are found which contain denatured protein or peptide material. The process of denaturation of protein requires the presence of excessive heat, organic solvents, or oxidizing acids (OA). It seems that only OA could produce these effects since the other two are not present in the disease. Macrophages can produce the anion of an oxidizing acid known as peroxynitrite (OONO). This material is formed from two free radical gases, namely superoxide anion [.O2]- and nitric oxide (.N = O). Although (OONO)- is very reactive (1000 times more oxidizing than hydrogen peroxide), its half life in solution is only 1 to 2 seconds. Therefore, when it oxidizes a substance (such as protein) peroxynitrite disappears. The brain contains cells called Microglia which are produced from monocytes in the same way as other types of macrophages from the lung and liver etc. The macrophages from the lung (alveolar) and liver (Kupfer cells) produce large amounts of peroxynitrite when activated by particles (silica) or infectious agents (lipopolysaccharide or interferon). Microglia produce highly oxidizing substances as well, but no one has ever measured production of peroxynitrite from these cells. Assuming that Microglia produce peroxynitrite, or other similar oxidants, anti-oxidant and anti-inflammatory drugs should be helpful in treatment of early forms of the disease. In addition, large doses of anti-oxidant vitamin C and vitamin E might be helpful to people with Alzheimer's disease

  444. van Rensburg SJ, Daniels WM, Potocnik FC, van Zyl JM, Taljaard JJ, Emsley RA (1997) A new model for the pathophysiology of Alzheimer's disease. Aluminium toxicity is exacerbated by hydrogen peroxide and attenuated by an amyloid protein fragment and melatonin. S.Afr.Med.J. 87:1111-1115
    Abstract: OBJECTIVES: Although Alzheimer's disease (AD) is the leading cause of dementia in developed countries, there is an as yet unexplained lower prevalence of the disease in parts of Africa. AD is characterised by a catastrophic loss of neurons; free radicals (oxidative toxins) have been implicated in the destruction of the cells through the process of lipid peroxidative damage of cell membranes. Previously aluminium (Al) and a fragment of beta amyloid (A beta 25-35) were shown to exacerbate free-radical damage, while melatonin reduced this effect. The aim of the present study was: (i) to investigate the conditions determining the toxicity of Al and A beta 25-35; and (ii) to assess whether melatonin could attenuate the damage done by both aluminium and the amyloid fragment, thus suggesting a pathway for the aetiology of AD. DESIGN: An in vitro model system was used in which free radicals were generated, causing lipid peroxidation of platelet membranes, thus simulating the disease process found in the brain. RESULTS: 1. Al and A beta 25-35 caused lipid peroxidation in the presence of the iron (II) ion (Pe2+), Al being more toxic than A beta 25-35. 2. A beta 25-35 attenuated the lipid peroxidation promoted by Al. 3. Hydrogen peroxide (H2O2) greatly exacerbated the toxicity of Al and A beta 25-35. 4. Melatonin prevented lipid peroxidation by Al and A beta 25-35 in the absence of H2O2, but only reduced the process when H2O2 was present. CONCLUSIONS: In the light of the results obtained from the present study, the following hypotheses are formulated. 1. In AD, excessive quantities of Al are taken up into the brain, where the Al exacerbates iron-induced lipid peroxidation in the lysosomes. 2. In response, the normal synthetic pathway of amyloid protein is altered to produce A beta fragments which attenuate the toxicity of Al. In the process of sequestering the Al and iron, immature plaques are formed in the brain. 3. Microglia are activated, in an attempt to destroy the plaques by secreting reactive oxygen species such as H2O2. At this point in the disease process, lipid peroxidation causes a catastrophic loss of brain cells. 4. Melatonin, together with other free radical scavengers in the brain, reduces the free-radical damage caused by Al and A beta, except in the latter stages of the disease process. Since melatonin is produced by the pineal gland only in the dark, the excess of electric light in developed countries may help explain why AD is more prevalent in these countries than in rural Africa

  445. Velazquez P, Cribbs DH, Poulos TL, Tenner AJ (1997) Aspartate residue 7 in amyloid beta-protein is critical for classical complement pathway activation: implications for Alzheimer's disease pathogenesis. Nat.Med. 3:77-79
    Abstract: Fibrillar amyloid beta-protein has been implicated in the pathogenesis of Alzheimer's disease because of its neurotoxicity and its ability to activate complement. Reactive Microglia, astrocytes and complement (C') components (reviewed in ref. 6) are associated with senile plaques, the fibrillar, beta-sheet assemblies of amyloid beta-peptide found predominantly in brain from individuals with AD (ref. 7). These indications of inflammatory events are not prevalent in the nonfibrillar "diffuse" plaques often seen in age-matched control cases without dementia. Clinical studies over the past several years have correlated the use of anti-inflammatory drugs with a decrease in the incidence and progression of AD dementia and/or dysfunction, supporting a role for gliosis and inflammation in AD pathogenesis (reviewed in ref. 6). C5a, a product of C' activation, is chemotactic for Microglia. Thus, complement activation provides a specific mechanism for recruiting reactive glial cells to the site of the fibrillar amyloid beta-protein plaque, which could lead to inflammatory events, neuronal dysfunction and degeneration. With the use of truncated amyloid beta-peptides, the region of amyloid beta-protein limited by residues 4 and 11 has been identified as critical in the interaction between amyloid beta-protein and C1q, the recognition component of the classical complement pathway (CCP), which results in the activation of C'. Furthermore, substitution of an isoaspartic acid for aspartic acid at amyloid beta-protein residue 7 resulted in the complete elimination of CCP-activating activity. A molecular model of this interaction has been generated that should be useful in the design of candidate therapeutic inhibitors of CCP activation by amyloid beta-protein

  446. Verbeek MM, Otte-Holler I, Ruiter DJ, De Waal RM (1997) [Inflammatory mechanisms in the pathogenesis of Alzheimer's disease]. Tijdschr.Gerontol.Geriatr. 28:213-218
    Abstract: Senile plaques belong to the pathological hallmarks of the brains of patients with Alzheimer's disease. There is an increasing amount of evidence that the formation of senile plaques is accompanied by an acute phase reaction, involving the production of several inflammation-associated proteins and the activation of Microglial cells. The products of these inflammatory reactions may contribute to the fibrillogenesis of the amyloid beta protein, the major constituent of senile plaques. Both fibrils of the amyloid beta protein and products of activated Microglial cells may be neurotoxic, leading to neuronal degeneration and to clinical symptoms of dementia. Recent epidemiological findings have drawn attention to the possibility of therapy with anti-inflammatory agents. Although the results of these studies suggest a beneficial effect of such therapy, further study is warranted to gain more insight into the fundamental aspects of such treatment as well as to develop specific drugs that have little side-effects

  447. Vitek MP, Snell J, Dawson H, Colton CA (1997) Modulation of nitric oxide production in human macrophages by apolipoprotein-E and amyloid-beta peptide. Biochem.Biophys.Res.Commun. 240:391-394
    Abstract: Induction of oxidative stress has been implicated as a causative factor in chronic neurodegenerative diseases such as Alzheimer's disease. Apolipoprotein-E (apoE) and amyloid-beta peptide (A beta) have been reported to alter the redox state of the brain. Using human monocyte-derived macrophages as a model of brain Microglia, physiological levels of apolipoprotein-E were found to stimulate nitric oxide (NO) production in polyinosinic:polycytidylic acid (poly I:C) primed cells. ApoE treatment released 68% more NO than cells treated with poly I:C alone and almost threefold more NO than unprimed cells. In contrast to mouse Microglia, human cells failed to generate NO in response to A beta peptides, with or without poly I:C treatments. Furthermore, the combination of A beta plus apoE inhibited the increase in NO production induced by apoE. Since Alzheimer's is strongly associated with the presence of an APOE4 allele, our study predicts a mechanism where apoE and A beta regulate nitric oxide production in human brain

  448. Wallace MN, Geddes JG, Farquhar DA, Masson MR (1997) Nitric oxide synthase in reactive astrocytes adjacent to beta-amyloid plaques. Exp.Neurol. 144:266-272
    Abstract: This study provides the first evidence that nitric oxide is released by astrocytes surrounding beta-amyloid plaques. Nitric oxide is involved in many neuropathological conditions and can have either a neuroprotective or a neurotoxic function depending on its concentration and the redox state of the tissue. It is produced by the enzyme nitric oxide synthase, which can be located by a simple histochemical technique for demonstrating NADPH diaphorase. Using this method we examined tissue from 10 brains where there were varying numbers of beta-amyloid plaques in the cerebral cortex. In the 6 brains with moderate or high densities of plaques, primitive and cored plaques were associated with between 1 and 10 reactive astrocytes that contained NADPH diaphorase or were immunoreactive for the inducible form of nitric oxide synthase. In the 4 brains which had only low densities of plaques, the plaques were not associated with diaphorase-containing astrocytes. The percentage of plaques associated with 1 or more NADPH diaphorase-containing astrocyte varied between 1 and 21% and was correlated with the density of plaques. Astrocytes were the only form of NADPH diaphorase-positive glial cell associated with the plaques. There was no evidence of any nitric oxide synthase occurring in Microglia

  449. Weldon DT, Maggio JE, Mantyh PW (1997) New insights into the neuropathology and cell biology of Alzheimer's disease. Geriatrics 52 Suppl 2:S13-S16
    Abstract: Several lines of evidence, including newly discovered genetic mutations, suggest that beta-amyloid (A beta) is directly involved in the neuropathology observed in familial and sporadic forms of Alzheimer's disease (AD). Rather than exerting its neurotoxicity directly, results from our laboratory suggest that fibrillar A beta (fA beta) activates Microglia and astrocytes upon injection into the rat brain. The Microglia and astrocytes, in turn, form a functional barrier between A beta and surrounding neurons. An increase in inducible nitric oxide synthase (iNOS) immunoreactivity is observed in activated Microglia and astrocytes, and specific subpopulations of neurons are lost in fA beta injection areas versus controls. These data, coupled with recent discoveries of the A beta association with the receptor for advanced glycation end products (RAGE) and the class A scavenger receptors (SR), support the hypothesized role of inflammatory mechanisms in AD neurotoxicity

  450. Xia M, Qin S, McNamara M, Mackay C, Hyman BT (1997) Interleukin-8 receptor B immunoreactivity in brain and neuritic plaques of Alzheimer's disease. Am.J.Pathol. 150:1267-1274
    Abstract: Cytokines mediate inflammatory responses through their receptors in the hematopoietic system. In a search for potential mediators of inflammatory responses in Alzheimer's disease, we examined brain for cytokine receptors. Herein we describe interleukin-8 receptor B (IL-8RB, also termed CXCR2) immunoreactivity in the central nervous system. Strong IL-8RB immunoreactivity is present in both Alzheimer's disease and control brains. Neurons, dendrites, and axons are clearly immunoreactive. In Alzheimer's disease, IL-8RB immunoreactivity is also present in some swollen dystrophic neurites of neuritic plaques. Double staining and confocal microscopic analysis reveals that these IL-8RB-positive neurites in plaques are neurofilament positive and are distinct from astrocytic or Microglial processes. In general, these IL-8RB-positive neurities do not co-localize with PHF-1 or AT8 (hyperphosphorylated tau) immunoreactive neurites but instead co-localize with beta PP-positive neurites. These results demonstrate for the first time IL-8RB immunoreactivity in the central nervous system and imply a new role for this receptor outside the hematopoietic system. The strong presence of IL-8RB on neurons and the potential of glial cells to produce IL-8 suggest that this system might mediate neuronal-glial interactions

  451. Yamada T, Yoshiyama Y, Kawaguchi N (1997) Expression of activating transcription factor-2 (ATF-2), one of the cyclic AMP response element (CRE) binding proteins, in Alzheimer disease and non-neurological brain tissues. Brain Res. 749:329-334
    Abstract: Cyclic AMP response element (CRE) is a specific DNA sequence which mediates transcriptional activation in the response to the cyclic AMP-activated and protein kinase A dependent signaling pathway. We examined the localization of one of the CRE binding proteins which is preferentially expressed in the brain, activating transcription factor-2 (ATF-2), by immunohistochemistry and Southwestern histochemistry, using the brains of neurologically normal and Alzheimer disease (AD) cases. In all brains, the anti-ATF-2 antibody stained white matter Microglial cells. In AD, the cytoplasm of some cortical neurons was also positively stained, but no such staining was seen in the neocortex in non-neurological cases staining. However, both the nuclei and cytoplasm of some hippocampal neurons were positive in non-neurological brain tissues. In AD, except for severely damaged areas such as CA1, positive neuronal staining was seen. Southwestern histochemistry gave the same results as immunohistochemistry. These data suggest that the localization of ATF-2 in cortical neurons in AD may reflect early pathological changes characteristic of AD, and that these histochemistrical methods may allow one to differentiate between healthy and mildly damaged neurons

  452. Yamada T, Tsuboi Y, Takahashi M (1997) Interrelationship between beta-amyloid deposition and complement-activated oligodendroglia. Dement.Geriatr.Cogn Disord. 8:267-272
    Abstract: Complement-activated oligodendroglia (CAOs) are thought to represent complement bearing damaged oligodendroglia for opsonization. The interrelationship between CAOs and amyloid deposits was examined by immunohistochemistry in the parietal lobe of patients with Parkinson's disease, diffuse Lewy body disease, and pallido-nigro-luysial atrophy. In all brains, the anti-C4d antibody stained numerous CAOs. Anti-beta-amyloid protein (anti-A beta) antibody revealed moderate numbers of senile plaques, including some of the classical type. In both the grey and the white matter amyloid deposits were frequently associated with the myelinated axons of CAOs. CAOs were occasionally associated with phagocytosing Microglial cells. Immunoelectron microscopy also showed a close relationship between phagocytosing Microglia and A beta deposition. On some occasions. A beta deposits were seen in C4d-positive oligodendroglial cell bodies. These results indicate that damaged myelinated axons, which contain accumulated amyloid precursor protein, are the source of A beta, and that CAOs may be initial targets for A beta deposits forming the classical senile plaques

  453. Zarow C, Barron E, Chui HC, Perlmutter LS (1997) Vascular basement membrane pathology and Alzheimer's disease. Ann.N.Y.Acad.Sci. 826:147-160
    Abstract: We have previously demonstrated that the capillary vascular basement membrane (VBM) is pathologically altered in Alzheimer's disease (AD). This microangiopathy is highlighted by the immunocytochemical localization of the three principal intrinsic VBM components: heparan sulfate proteoglycan, collagen type IV, and laminin. These three VBM components also immunolable amyloid deposits and senile plaque-associated glial processes. The present study examines the ultrastructure of the VBM in one brain region severely affected (temporal gyrus) and one relatively spared (cerebellum) from the lesions of AD in both AD and neurological control cases. The cross-sectional area as well as the width of the VBM were found to be greater in AD cortical capillaries. In addition, we found ultrastructural evidence for the activation of Microglial-related perivascular cells, and their apparent extravasation through the VBM, findings consistent with the hypothesis that these cells are being recruited as part of a disease-related immune response. The recruitment of these "resting" Microglial-like cells from their intra-VBM location to plaques and tangles in AD may explain (1) the thickening and vacuolization of the VBM; (2) the specificity of this VBM alteration to brain regions where there are plaques and tangles; and (3) the source of some of the large number of activated Microglia in these affected areas. Thus, while VBM alterations may not be specific to AD, these changes appear to be specifically related to the disease process

  454. Afagh A, Cummings BJ, Cribbs DH, Cotman CW, Tenner AJ (1996) Localization and cell association of C1q in Alzheimer's disease brain. Exp.Neurol. 138:22-32
    Abstract: The complement protein, C1q, has been shown to bind to fibrillar beta-amyloid, resulting in the activation of the classical complement pathway. C1q has also been found associated with most but not all amyloid deposits in brain. To determine whether C1q is exclusively associated with plaques containing the fibrillar form of beta-amyloid, normal and Alzheimer brain were immunohistochemically double labeled using thioflavine, which specifically stains beta-amyloid in a beta-sheet conformation, and an affinity- purified antibody to human C1q. C1q immunostaining was colocalized with nearly all thioflavine-positive plaques, while C1q was not detected in beta-amyloid immunopositive plaques which were thioflavine-negative. Beta-amyloid plaques in nondemented controls (which are typically thioflavine-negative) were also negative for C1q. Microglia and astrocytes of reactive morphology were also associated with C1q-positive plaques and neurons. Interestingly, many neuronal cells in the AD brain, but not Microglia or astrocytes, stained prominently with anti-C1q. Neurons in control brain were not C1q positive. Our data suggest that some of these C1q-positive structures were neurofibrillary tangles immunoreactive for hyperphosphorylated tau, which may be binding extracellular C1q. However, a large number of the C1q-positive neurons had intact cell morphology; suggesting that these cells may be synthesizing this critical complement component. Since the presence of C1q suggests the activation of complement and/or the activation of proinflammatory events, and the specific class of plaques that contain C1q are the type that corresponds to observed clinical dementia, these findings further support the hypothesis that complement plays a role in the pathogenesis of AD

  455. Aisen PS (1996) Inflammation and Alzheimer disease. Mol.Chem.Neuropathol. 28:83-88
    Abstract: Inflammatory mechanisms are active in patients with Alzheimer disease. Serum elevations of acute phase proteins such as alpha 1-antichymotrypsin, along with deposition of inflammatory cytokines in the brain, suggest a "cerebral acute phase response" contributing to amyloid deposition and tissue destruction. Activated Microglia possessing HLA-DR surface markers accumulate around amyloid plaques. The complement cascade leads to generation of the membrane attack complex, which may directly damage neuronal membranes. This growing body of evidence suggests that empirical trials of anti-inflammatory drugs are now appropriate to test the hypothesis that suppression of these mechanisms will slow the rate of progression of Alzheimer disease. Several drugs useful in the treatment of rheumatic diseases are candidates for study in Alzheimer disease, including glucocorticoids, antimalarial drugs, and colchicine. Pilot studies of the synthetic glucocorticoid prednisone indicate that treatment with a moderate dose is well tolerated in patients with Alzheimer disease, and suppresses serum levels of acute phase proteins. Based on this experience, a multicenter parallel-design placebo-controlled trial has been initiated with Alzheimer's Disease Cooperative Study to determine whether treatment with prednisone can slow the rate of progression of Alzheimer disease

  456. Akiyama H, Schwab C, Kondo H, Mori H, Kametani F, Ikeda K, McGeer PL (1996) Granules in glial cells of patients with Alzheimer's disease are immunopositive for C-terminal sequences of beta-amyloid protein. Neurosci.Lett. 206:169-172
    Abstract: Granular structures that are recognized by antibodies specific for the C-terminal but not the N-terminal sequences of the beta-amyloid protein (A beta) fragments are present in a subset of Microglia and astrocytes in Alzheimer brain tissue. The immunohistochemical profile indicates that the A beta in these granules is truncated between the residues 17 and 31 and terminates at the residue 42 or 43. Such granule-containing glia occur only in brain areas with the heavy A beta deposits. Whether the intraglial A beta fragments accumulate as a result of phagocytosis of extracellular A beta or are formed intracellularly by glial cells from amyloid precursor protein (APP) remains unknown

  457. Ard MD, Cole GM, Wei J, Mehrle AP, Fratkin JD (1996) Scavenging of Alzheimer's amyloid beta-protein by Microglia in culture. J.Neurosci.Res. 43:190-202
    Abstract: Deposits of amyloid beta-protein (A beta) form the cores of the pathological plaques which characterize Alzheimer's disease. The mechanism of formation of the deposits is unknown; one possibility is failure of a clearance mechanism that would normally remove the protein from brain parenchyma. This study has investigated the capacity of the central nervous system (CNS) phagocytes, Microglia cells, to clear exogenous A beta 1-42 from their environment. Cultured Microglia from adult rat CNS have a high capacity to remove A beta from serum-free medium, shown by immunoblotting experiments. A beta from incubation medium was attached to the cell surface and could be identified by immunocytochemistry at the light or electron microscopic (EM) level; by EM, A beta also appeared in phagosome-like intracellular vesicles. Light microscopic immunocytochemistry combined with computer-assisted image analysis showed that cells accumulated A beta within 24 hr. from culture medium containing from 1 to 20 micrograms/ml A beta. Microglial accumulation of A beta was substantially reduced in the presence of fetal bovine serum. Addition of the protease inhibitor leupeptin to incubation medium with serum resulted in accumulation of A beta in a membrane-bound intracellular compartment, but not at the cell surface. The increase in intracellular accumulation in the presence of the protease inhibitor indicates a Microglial capacity for intracellular degradation of A beta in the absence of inhibition. The change from predominantly cell-surface accumulation in serum-free medium to predominantly intracellular accumulation with serum may be explained by the presence in serum of carrier proteins that complex with A beta and target it to cell surface receptors capable of stimulating endocytosis. Microglia were also cultured on unfixed cryostat sections of human brain tissue containing Alzheimer's plaques. Very little A beta from the tissue was accumulated by the cells, although cultured Microglia were found in direct contact with anti-A beta immunopositive plaques. Possibly A beta in tissue sections was complexed with other proteins which either inhibited its uptake by Microglia or enhanced its proteolysis, preventing cellular accumulation of immunostainable A beta. The results indicate that cultured Microglia effectively remove A beta from tissue culture medium and from the surface of the dish and concentrate monomer and aggregates of A beta either on the cell surface or intracellularly. This process may be modified by proteins present in Alzheimer's brain sections

  458. Bitting L, Naidu A, Cordell B, Murphy GM, Jr. (1996) Beta-amyloid peptide secretion by a Microglial cell line is induced by beta-amyloid-(25-35) and lipopolysaccharide. J.Biol.Chem. 271:16084-16089
    Abstract: beta-Amyloid protein (betaAP) deposition is a neuropathologic hallmark of Alzheimer's disease (AD). Yet, the source of cerebral betaAP in AD is controversial. We examined the production of betaAP by the BV-2 immortalized Microglial cell line using a sensitive enzyme immunoassay. Constitutive production of betaAP was detected in conditioned media from unstimulated BV-2 cells. Further, production of betaAP was induced by treatment of cultures by lipopolysaccharide (LPS) or betaAP-(25-35) and was inhibited by the calpain protease inhibitor MDL 28170. Treatment of BV-2 cells with LPS or betaAP-(25-35) did not affect cell-associated beta-amyloid precursor protein levels. These findings suggest that Microglia may be an important source of betaAP in AD, and that Microglial production of betaAP may be augmented by proinflammatory stimuli or by betaAP itself

  459. Breitner JC (1996) Inflammatory processes and antiinflammatory drugs in Alzheimer's disease: a current appraisal. Neurobiol.Aging 17:789-794
    Abstract: The study of risk factors and protective influences can yield clues to the pathogenesis of Alzheimer's disease (AD). Intervention on such factors can effect disease prevention or treatment while etiology remains unknown. Most known AD risk factors offer no prospect of prevention, but 14 of 15 relevant publications since 1987 suggest that the symptoms of AD are prevented or attenuated by antiinflammatory treatments. These findings are supported by numerous circumstantial findings suggesting a role for cytokines and acute phase reactants in the pathogenesis of AD. In particular, activated Microglia and/or reactive astrocytes, found within or near all AD lesions, are thought to kill target cells by using either free radicals or the classical complement pathway. These mechanisms should be suppressed by glucocorticoids, but the available data suggest that nonsteroidal antiinflammatory drugs (NSAIDs) exert a stronger protective influence than steriods. NSAIDs (but not steroids) suppress the action of cyclooxygenases (COX), which catalyze synthesis of prostaglandins. The latter are intermediaries in the postsynaptic signal transduction cascade of cells with NMDA-type glutamate receptors. They may also potentiate glutamatergic transmission by inhibiting astrocytic reuptake of glutamate. Both mechanisms can potentiate excitotoxic cell death. Further work is needed to clarify whether steroids, NSAIDs, or both prevent or attenuate the symptoms of AD

  460. Cheetham JE, Martzen MR, Kazee AM, Coleman PD (1996) Gap-43 message levels in anterior cerebellum in Alzheimer's disease. Brain Res.Mol.Brain Res. 36:145-151
    Abstract: We have previously reported that decreased growth-associated protein (GAP-43) message in frontal association cortex (area 9) of Alzheimer's disease (AD) patients is associated with increased density of neurons containing neurofibrillary tangles (NFTs) [9]. This finding leads to the hypothesis that decreased GAP-43 message in AD may be related to NFTs, rather than to some other aspect of AD pathology. Therefore, we predicted that in areas of brain unaffected by NFTs in AD the GAP-43 message levels should be similar to those of controls. The cerebellum is known to have a number of pathologies of AD, including diffuse plaques (DPs), Microglial activation and reactive astrocytes. NFTs, however, are not typically found in the cerebellum. mRNA was extracted from anterior cerebellum of AD and control cases, Northern- and slot-blotted and hybridized against a GAP-43 probe. Poly(dT) and glucose-3-phosphate dehydrogenase probes were used for normalization. The average relative GAP-43 message level was 0.582 in the AD cases and 0.448 in control cases. This 23% difference failed to reach statistical significance. Regression analysis within the AD group demonstrated that GAP-43 message level in cerebellar cortex was not significantly correlated with diffuse plaque density in cerebellar cortex. GAP-43 message levels in cerebellar cortex were also not correlated with summed density of neuritic plaques or summed density of NFTs in cortical regions-here used as an index of severity of disease. The data reported here also emphasize that the (NFT-dependent) reduction in GAP-43 mRNA levels previously reported in frontal association cortex in Alzheimer's disease [9] appears to be region specific and not a general brain phenomenon. The preservation of normal GAP-43 message levels in the cerebellum in AD is consistent with the hypothesis that events related to NFT formation have a major impact on the expression of GAP-43 in Alzheimer's disease

  461. Christie RH, Freeman M, Hyman BT (1996) Expression of the macrophage scavenger receptor, a multifunctional lipoprotein receptor, in Microglia associated with senile plaques in Alzheimer's disease. Am.J.Pathol. 148:399-403
    Abstract: The macrophage scavenger receptor is a multifunctional receptor whose ligands include oxidized low density lipoprotein (LDL), as well as several other polyanionic macromolecules. Although the capacity of the receptor to bind modified LDL has implicated it in the process of atherosclerosis, its physiological role remains uncertain. We have examined human brain for expression of macrophage scavenger receptor as part of ongoing studies of lipoprotein receptors in the central nervous system. The receptor is expressed on Microglia, but not on astrocytes, neurons, or vessel-associated structures. In Alzheimer disease, there is strong expression of the scavenger receptor in association with senile plaques

  462. Christie RH, Chung H, Rebeck GW, Strickland D, Hyman BT (1996) Expression of the very low-density lipoprotein receptor (VLDL-r), an apolipoprotein-E receptor, in the central nervous system and in Alzheimer's disease. J.Neuropathol.Exp.Neurol. 55:491-498
    Abstract: The very low density lipoprotein receptor (VLDL-r) is a cell-surface molecule specialized for the internalization of multiple diverse ligands, including apolipoprotein E (apoE)-containing lipoprotein particles, via clathrin-coated pits. Its structure is similar to the low-density lipoprotein receptor (LDL-r), although the two have substantially different systemic distributions and regulatory pathways. The present work examines the distribution of VLDL-r in the central nervous system (CNS) and in relation to senile plaques in Alzheimer disease (AD). VLDL-r is present on resting and activated Microglia, particularly those associated with senile plaques (SPs). VLDL-r immunoreactivity is also found in cortical neurons. Two exons of VLDL-r mRNA are differentially spliced in the mature receptor mRNA. One set of splice forms gives rise to receptors containing (or lacking) an extracellular O-linked glycosylation domain near the transmembrane portion of the molecule. The other set of splice forms appears to be brain-specific, and is responsible for the presence or absence of one of the cysteine-rich repeat regions in the binding region of the molecule. Ratios of the receptor variants generated from these splice forms do not differ substantially across different cortical areas or in AD. We hypothesize that VLDL-r might contribute to metabolism of apoE and apoE/A beta complexes in the brain. Further characterizations of apoE receptors in Alzheimer brain may help lay the groundwork for understanding the role of apoE in the CNS and in the pathophysiology of AD

  463. Colton C, Wilt S, Gilbert D, Chernyshev O, Snell J, Dubois-Dalcq M (1996) Species differences in the generation of reactive oxygen species by Microglia. Mol.Chem.Neuropathol. 28:15-20
    Abstract: Although a variety of potential sources for reactive oxygen species (ROS) exist in the CNS, brain macrophages, i.e., the Microglia, generate large quantities of these reactive species, particularly in response to injury or inflammatory signals. In order to understand how Microglia contribute to changes in oxidative status of the CNS and how this might related to disease states, such as Alzheimer disease (AD), we have examined the regulation of superoxide anion and nitric oxide production from rodent and human Microglia. Our results indicate that Microglia from all species we have studied release superoxide anion, but produce significantly different amounts in response to the same activating agents. Species differences are also found in the ability to generate nitric oxide (NO). In particular, mouse Microglia generate large quantities of NO when stimulated, but human and hamster Microglia do not produce measurable amounts under the same stimulation conditions. These species differences are important to consider when modeling human disease processes from rodent studies

  464. Dickson DW, Sinicropi S, Yen SH, Ko LW, Mattiace LA, Bucala R, Vlassara H (1996) Glycation and Microglial reaction in lesions of Alzheimer's disease. Neurobiol.Aging 17:733-743
    Abstract: Single, double, and triple immunostaining of cryostat sections of elderly normal and Alzheimer disease (AD) brain was performed with monoclonal and polyclonal antibodies to advanced glycation end products (AGE). The sections were counterstained with thioflavin-S or with immunocytochemistry for A beta and also stained with markers for Microglia. AGE-immunoreactivity was detected in senile plaques and neurofibrillary tangles (NFT). AGE immunoreactivity was most intense in dense or reticular amyloid deposits and extracellular NFT, while intracellular NFT and diffuse amyloid had less AGE immunoreactivity. This pattern of immunoreactivity was similar to that noted in previous studies with antibodies to apolipoprotein-E (apo-E). Therefore, double labeling with antibodies to apo-E and AGE was performed. AGE immunoreactivity colocalized to a very high degree with apo-E immunoreactivity, except that relatively more intense apo-E immunoreactivity was detected in amyloid deposits and more intense AGE immunoreactivity in NFT. The lesions that were immunostained with antibodies to AGE and apo-E were often, but not always, associated with a local Microglial reaction. The results raise the possibility that apo-E or a fragment of apo-E may be glycated. Biochemical studies are needed to determine the extent of possible apo-E glycation in AD. The present results raise the possibility that glycation may serve as one of the signals for activation of Microglia associated with amyloid deposits and extracellular NFT

  465. Eikelenboom P, Veerhuis R (1996) The role of complement and activated Microglia in the pathogenesis of Alzheimer's disease. Neurobiol.Aging 17:673-680
    Abstract: A variety of inflammatory mediators including complement activation products, protease inhibitors, and cytokines are colocalized with beta-amyloid (A beta) deposits in the Alzeimer's disease (AD) brain. Activation products of the early complement components C1, C4, and C3 are always found in neuritic plaques and to a lesser extent in varying numbers of diffuse plaques. In contrast to these findings, no immunohistochemical evidence was obtained for the presence of the late complement components C7 and C9 and the complement membrane attack complex in the neuropathological lesions in AD brains. The mRNA encoding the late complement components C7 and C9 appears to be hardly or not detectable. These findings indicate that in AD the complement system does not act as an inflammatory mediator through membrane attack complex formation, but through the actions of the early complement products. In this review we focus on the role of complement in the pathological amyloid cascade in AD. In our opinion, the early complement activation products play a crucial role as mediators between the A beta deposits and the inflammatory responses leading to neurotoxicity

  466. El Khoury J, Hickman SE, Thomas CA, Cao L, Silverstein SC, Loike JD (1996) Scavenger receptor-mediated adhesion of Microglia to beta-amyloid fibrils. Nature 382:716-719
    Abstract: A pathological hallmark of Alzheimer's disease is the senile plaque, containing beta-amyloid fibrils, Microglia and astrocytes. Beta-amyloid fibrils exert a cytotoxic effect on neurons, and stimulate Microglia to produce neurotoxins, such as reactive oxygen species. Mononuclear phagocytes, including Microglia, express scavenger receptors that mediate endocytosis of oxidized low-density lipoproteins, and adhesion to glucose-modified extra-cellular matrix proteins. Here we report that class A scavenger receptors mediate adhesion of rodent Microglia and human monocytes to beta-amyloid fibril-coated surfaces leading to secretion of reactive oxygen species and cell immobilization. Thus, class A scavenger receptors are potential therapeutic targets in Alzheimer's disease

  467. Finch CE, Marchalonis JJ (1996) Evolutionary perspectives on amyloid and inflammatory features of Alzheimer disease. Neurobiol.Aging 17:809-815
    Abstract: We propose that the amyloid deposits in senile plaques of Alzheimer's Disease (AD) result from ancient mechanisms in wound-healing and inflammatory processes that preceded the evolution of the inducible combinatorial immune responses characteristic of jawed vertebrates. AD plaques are unlike active plaques in MS, because antibodies, T-cells and, B cells are not conspicuous components of senile plaques or other loci of degeneration. However, senile plaques contain amyloids and other inflammatory proteins of ancient origin that appear to be made by local brain cells, including neurons, astrocytes, and Microglia. We describe a highly conserved 16-mer found in pentrakins from mammals and from the horseshoe crab. The senile plaque thus provides a novel opportunity to study primitive features of complement-mediated inflammatory responses in the absence of immunoglobulins

  468. Fukumoto H, Asami-Odaka A, Suzuki N, Iwatsubo T (1996) Association of A beta 40-positive senile plaques with Microglial cells in the brains of patients with Alzheimer's disease and in non-demented aged individuals. Neurodegeneration. 5:13-17
    Abstract: To gain insight into the role of Microglia in the formation of senile plaques (SP), especially in the generation of the two major molecular species of amyloid beta protein (A beta) with different carboxyl (C)-termini, A beta 40 and A beta 42(43), we conducted double immunolabelling studies on tissue sections from the brains of Alzheimer's disease (AD) and non-demented aged individuals using antibodies to the C-termini of A beta and ferritin, a marker for Microglia. All SP were A beta 42(43)-positive in AD as well as in non-demented individuals, only a proportion of which were A beta 40-positive. Both in AD and in non-demented individuals, approximately 2/3 of the A beta 40-positive SP were typical SP with amyloid cores, these being almost invariably associated with Microglia. A beta 40-positive, uncored SP were also frequently associated with Microglia (mean, 74%), whereas only 24% of A beta 40-negative, uncored SP contained Microglia. These results suggest that Microglia may play a role in the maturation of SP, especially in the generation of A beta 40

  469. Giulian D, Haverkamp LJ, Yu JH, Karshin W, Tom D, Li J, Kirkpatrick J, Kuo LM, Roher AE (1996) Specific domains of beta-amyloid from Alzheimer plaque elicit neuron killing in human Microglia. J.Neurosci. 16:6021-6037
    Abstract: Alzheimer's disease (AD) is found to have striking brain inflammation characterized by clusters of reactive Microglia that surround senile plaques. A recent study has shown that Microglia placed in contact with isolated plaque fragments release neurotoxins. To explore further this process of immunoactivation in AD, we fractionated plaque proteins and tested for the ability to stimulate Microglia. Three plaque-derived fractions, each containing full-length native A beta 1-40 or A beta 1-42 peptides, elicited neurotoxin release from Microglia. Screening of various synthetic peptides (A beta 1-16, A beta 1-28, A beta 12-28, A beta 25-35, A beta 17-43, A beta 1-40, and A beta 1-42) confirmed that Microglia killed neurons only after exposure to nanomolar concentrations of human A beta 1-40 or human A beta 1-42, whereas the rodent A beta 1-40 (5Arg-->Gly, 10Tyr-->Phe 13His-->Arg) was not active. These findings suggested that specific portions of human A beta were necessary for Microglia-plaque interactions. When coupled to microspheres, N-terminal portions of human A beta (A beta 1-16, A beta 1-28, A beta 12-28) provided anchoring sites for Microglial adherence whereas C-terminal regions did not. Although itself not toxic, the 10-16 domain of human A beta was necessary for both Microglial binding and activation. Peptide blockade of Microglia-plaque interactions that occur in AD might prevent the immune-driven injury to neurons

  470. Hollister RD, Kisiel W, Hyman BT (1996) Immunohistochemical localization of tissue factor pathway inhibitor-1 (TFPI-1), a Kunitz proteinase inhibitor, in Alzheimer's disease. Brain Res. 728:13-19
    Abstract: Senile plaques in Alzheimer's disease (AD) are composed principally of A beta, a 4 kDa fragment of the amyloid precursor protein (APP). Longer forms of APP which contain a Kunitz proteinase inhibitor (KPI) domain are elevated in aged and in AD brains. Tissue factor pathway inhibitor-1 (TFPI) contains three tandem KPI domains and has been well characterized for its role as a natural anticoagulant in the extrinsic coagulation pathway. Functionally, the first two KPI domains of TFPI bind and inhibit the activity of factor Xa and VIIa respectively. In addition, TFPI and APP-KPI share a common clearance mechanism through the low density lipoprotein receptor-related protein (LRP). As part of an ongoing study of the role of KPI-containing proteins in AD, the current study examines TFPI localization in the brain. We report here that TFPI is immunohistochemically localized to Microglia in both AD and non-AD individuals and is localized to some senile plaques in AD. Western blot analyses indicate that the amount of TFPI is elevated in frontal cortex samples from AD brains. We propose that TFPI may play a cell specific role in proteinase regulation in the brain

  471. Hull M, Strauss S, Berger M, Volk B, Bauer J (1996) Inflammatory mechanisms in Alzheimer's disease. Eur.Arch.Psychiatry Clin.Neurosci. 246:124-128
    Abstract: In recent years many studies have indicated an involvement of inflammatory mechanisms in Alzheimer's disease (AD). Acute-phase proteins such as alpha 1-antichymotrypsin and c-reactive protein, elements of the complement system, and activated Microglial and astroglial cells are consistently found in brains of AD patients. Most importantly, also cytokines such as interleukin-6 (IL-6) have been detected in the cortices of AD patients, indicating a local activation of components of the unspecific inflammatory system. Up to now it has remained unclear whether inflammatory mechanisms represent a primary event or only an unspecific reaction to brain tissue damage. Therefore, we investigated whether IL-6 immunoreactivity could be found in plaques prior to the onset of neuritic changes, or whether the presence of this cytokine is restricted to later stages of plaque pathology. We confirmed our previous observation that IL-6 is detectable in a significant proportion of plaques in the brains of demented patients. In AD patients IL-6 was found in diffuse plaques in a significant higher ratio as would have been expected from a random distribution of IL-6 among all plaque types. This observation suggests that IL-6 may precede neuritic changes, and that immunological mechanism may be involved both in the transformation from diffuse to neuritic plaques in AD and in the development of dementia

  472. Jefferies WA, Food MR, Gabathuler R, Rothenberger S, Yamada T, Yasuhara O, McGeer PL (1996) Reactive Microglia specifically associated with amyloid plaques in Alzheimer's disease brain tissue express melanotransferrin. Brain Res. 712:122-126
    Abstract: Several investigations have implicated the involvement of metals in neuropathologies. In particular, the disruption of iron metabolism and iron transport molecules have been demonstrated in Alzheimer's disease (AD). We have identified a novel pathway of iron uptake into mammalian cells involving melanotransferrin, or p97, which is independent of the transferrin receptor. Here we investigated whether there is a possible link between this molecule and the pathology of AD. The distributions of melanotransferrin, transferrin and the transferrin receptor were studied immunohistochemically in brain tissues from AD cases. In brain tissues from AD, melanotransferrin and the transferrin receptor were highly localized to capillary endothelium, while transferrin itself was mainly localized to glial cells. In brain tissue derived from AD patients, melanotransferrin was additionally detected in a subset of reactive Microglia associated with senile plaques. Our demonstration that melanotransferrin mediates iron uptake through a pathway independent of the transferrin receptor indicates that this mechanism may have a role in AD

  473. Kalaria RN, Harshbarger-Kelly M, Cohen DL, Premkumar DR (1996) Molecular aspects of inflammatory and immune responses in Alzheimer's disease. Neurobiol.Aging 17:687-693
    Abstract: Recent advances indicate numerous molecular and cellular elements of the immune system are involved in the pathogenesis of Alzheimer's disease. Amyloid beta protein deposition induces many molecules associated with a predominantly local inflammatory response within the brain parenchyma. These responses also provoke the release of immune system mediators including cytokines, which all seem largely to be produced by reactive cells such as astrocytes and Microglia. Classical acute phase proteins of the pentraxin and serine protease inhibitor (serpin) families as well as a host of complement proteins and some coagulation factor seem the most intrinsically involved. These secreted molecules display variable binding with the amyloidotic lesions. Although our understanding of the molecular specificity and significance of the interaction of these proteins within the lesions is not replete, the development of unique inhibitors of the inflammatory reactions could provide therapeutic strategies to impede the pathogenetic process. Currently, this appears a more viable option than to inhibit amyloid beta production or modify amyloid beta precursor protein processing, an approach which seems more complex

  474. Kalaria RN, Cohen DL, Premkumar DR (1996) Cellular aspects of the inflammatory response in Alzheimer's disease. Neurodegeneration. 5:497-503
    Abstract: Cerebral amyloid beta protein deposition in Alzheimer's disease is associated with a predominantly local acute phase response that kindles release of various inflammatory and immune system mediators. The molecular events are accompanied by a profound cellular response which is largely orchestrated by Microglia. Current evidence suggests Microglia are primarily involved in phagocytic activity and may be responsible for inducing further neuronal damage by generating reactive oxygen species and proteolytic enzymes. Antiinflammatory measures that target complement activation as well as Microglial-mediated oxidative damage would provide rational therapeutic strategies

  475. Lorton D, Kocsis JM, King L, Madden K, Brunden KR (1996) beta-Amyloid induces increased release of interleukin-1 beta from lipopolysaccharide-activated human monocytes. J.Neuroimmunol. 67:21-29
    Abstract: Previous reports have demonstrated that IL-1 is elevated in the Alzheimer's disease brain. We propose that beta-amyloid (A beta) in senile plaques triggers Microglial interleukin-1(IL-1) release. Since Microglia and monocytes have similar lineage and functions, the human monocyte cell line, THP-1, was used to determine whether A beta peptides can stimulate release of IL-1 beta. THP-1 cells were grown in culture with LPS and incubated with various A beta peptides (0.5-10 microM). IL-1 released into the medium was measured using either an IL-1 beta ELISA or an IL-1 bioassay. Treatment of activated THP-1 cells with A beta 25-35, fibrillar A beta 1-40, or A beta 1-42 significantly elevated IL-1 beta release. A beta 25-35 with a scrambled sequence or non-fibrillar A beta 1-40 did not significantly change IL-1 beta release from activated THP-1 cells. The A beta 25-35- and fibrillar A beta 1-40 induced IL-1 beta release was dose-dependent. IL-1 released following treatment with A beta 25-35 and measured using an IL-1 bioassay gave similar results. The present report provides evidence that A beta is capable of elevating release of functional IL-1 beta, a potent pro-inflammatory cytokine, from macrophages/Microglia and provides support that a chronic local inflammatory response is an ongoing phenomenon within and surrounding senile plaques

  476. Lue LF, Brachova L, Civin WH, Rogers J (1996) Inflammation, A beta deposition, and neurofibrillary tangle formation as correlates of Alzheimer's disease neurodegeneration. J.Neuropathol.Exp.Neurol. 55:1083-1088
    Abstract: We evaluated entorhinal cortex and superior frontal gyrus for hallmarks of Alzheimer's disease (AD) pathology, including inflammation, in three patient sets: AD patients, nondemented elderly patients with few or no neurofibrillary tangles (NFTs) and amyloid beta peptide (A beta) deposits, i.e. normal controls (NC), and nondemented elderly patients with profuse entorhinal cortex NFTs and neocortical A beta deposits, i.e. high pathology controls (HPC). Membrane attack complex (C5b-9) immunoreactivity and immune activation of Microglia (MHCII expression) were used as general markers for inflammation. Compared to NC patients, AD patients exhibited significant cortical synapse loss, A beta deposition, NFT formation, and inflammation. HPC patients also had significantly elevated A beta deposition and NFT formation, but there was no evidence of synapse loss and little or no evidence of inflammation. Across patients and brain regions the measures of inflammation each accounted for significant percentages of the variance in synaptophysin immunoreactivity and each was more highly correlated with synapse estimates than NFT formation or A beta deposition

  477. Lue LF, Brachova L, Walker DG, Rogers J (1996) Characterization of glial cultures from rapid autopsies of Alzheimer's and control patients. Neurobiol.Aging 17:421-429
    Abstract: We have developed isolated and mixed cultures of Microglia, astrocytes, and oligodendrocytes from rapid (mean of 2 h 55 min) autopsies of nondemented elderly patients and patients with Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Cultures were derived from both the corpus callosum (CC) and superior frontal gyrus (SFG). Cultured Microglia phagocytosed latex beads, were reactive for Dil-acetylated low density lipoprotein, were immunoreactive for CD68 and major histocompatibility complex II markers, and were not immunoreactive for fibroblast, astrocyte, or oligodendrocyte markers. Cultured astrocytes included fibrous and protoplasmic types, were immunoreactive for GFAP, and were not immunoreactive for fibroblast, Microglia, or oligodendrocyte markers. Cultured oligodendrocytes were poorly adherent, were slow to develop, were immunoreactive for galactocerebroside, and were not immunoreactive for fibroblast, Microglia, or astrocyte markers. Because they are readily manipulated under controlled experimental conditions, and because they permit immediate access to individual cells and sets of cells from patients who have actually suffered the disease, these cultures may provide an important new tool for unravelling the etiology and pathogenesis of human CNS disorders

  478. Mann DM, Iwatsubo T, Snowden JS (1996) Atypical amyloid (A beta) deposition in the cerebellum in Alzheimer's disease: an immunohistochemical study using end-specific A beta monoclonal antibodies. Acta Neuropathol.(Berl) 91:647-653
    Abstract: We have used the end-specific monoclonal antibodies to amyloid beta-protein (A beta), BC05 and BA27, to investigate the molecular characteristics of the cored or stellate type of amyloid plaque that is sometimes present, along with the more common diffuse type of plaque, in the cerebellar cortex in (usually younger) cases of Alzheimer's disease. In five such cases of Alzheimer's disease the (many) cored plaques were strongly BA27, but less strongly BC05, immunopositive, indicating the presence of (much) A beta 40 and A beta 42(43), respectively. Diffuse plaques were only BC05 positive, except on rare occasions where a litter BA27 reactivity was present. Cerebellar cored plaques, like the diffuse plaques, were not associated with tau or astrocytic (glial fibrillary acid protein) immunoreactivity, though in contrast to cerebellar diffuse plaques, but like the cored plaques in the cerebral cortex, Microglial cells were usually present. The cause of this form of A beta deposition in the cerebellum is not known. Although congophilic angiopathy was severe in two patients, this was only mild in the other. Similar plaques were also seen in the cerebellum of most, but not all, of five other younger patients with chromosome 14-linked Alzheimer's disease and again, although congophilic angiopathy was severe in one such case with many cored plaques, this was not so in the others. At present the relationship (if any) between this pathological change and the possession of the chromosome 14 mutation of Alzheimer's disease or the occurrence of congophilic angiopathy remains uncertain

  479. Matsuo A, Walker DG, Terai K, McGeer PL (1996) Expression of CD43 in human Microglia and its downregulation in Alzheimer's disease. J.Neuroimmunol. 71:81-86
    Abstract: CD43 (leukosialin, sialophorin) expression in brain tissue of neurologically normal and Alzheimer disease (AD) cases was studied immunohistochemically. Abundant CD43-like immunoreactivity was detected in ramified Microglia of normal brain. It was also seen in residual leukocytes in capillaries and was faintly detectable on the surface of some normal appearing neurons. In AD brains, the overall expression of CD43 by Microglia was markedly lower than in control brains. This was in contrast to HLA-DR which was sharply upregulated due to the activated state of the Microglia. This is the first report of a Microglial marker which is more highly expressed in the resting or ramified state. Such expression is consistent with theories that CD43 plays an anti-adhesional role, and that cleavage occurs during cellular activation

  480. Mattson MP, Rydel RE (1996) Alzheimer's disease. Amyloid ox-tox transducers. Nature 382:674-675

  481. McGeer PL, McGeer EG (1996) Anti-inflammatory drugs in the fight against Alzheimer's disease. Ann.N.Y.Acad.Sci. 777:213-220
    Abstract: Lesions in Alzheimer disease are characterized by the assembly of a variety of cells and proteins associated with the immune system. Activated Microglia express high levels of MHC glycoproteins and receptors for complement. Small numbers of T-lymphocytes infiltrate tissue. Proteins of the classical complement pathway are closely connected with beta-amyloid deposits. Several materials associated with senile plaques, including beta-amyloid protein itself, bind C1q in vitro and activate the pathway. The membrane attack complex of complement, as well as proteins which defend against that complex, colocalize with dystrophic neurites. These data imply that an autodestructive process is occurring in Alzheimer's disease, and that anti-inflammatory drugs might be an effective form of therapy. Some epidemiological evidence and results of a pilot clinical trial support this hypothesis

  482. McRae A, Ling EA, Wigander A, Dahlstrom A (1996) Microglial cerebrospinal fluid antibodies. Significance for Alzheimer disease. Mol.Chem.Neuropathol. 28:89-95
    Abstract: Hallmark lesions of Alzheimer disease (AD) are filled with reactive immunocompetent Microglia, suggesting that immunological aderrations may participate in the pathophysiology of this disorder. If immune-mediated processes are closely linked to neuronal breakdown, it would be or importance to have a reliable means to detect these processes. Cerebrospinal fluid (CSF) antibodies are discussed as such potential sources. The seredipitous use of the developing rat central nervous system (CNS) unexpectedly demonstrated that some AD CSF recognize amoeboid Microglial cells. Similarly, AD CSF specifically stains activated Microglia and neural macrophages in experimentally induced lesions. A cell-culture technique is described that allows rapid screening of CSF antibodies. Examination of CSF from a diversified dementia population revealed that AD CSF, in contrast to other dementia CSF, displayed remarkable selectivity toward Microglial cells. Cortical biopsies from patients suspected to have AD were incubated with the patient's own CSF and that of confirmed AD patients. Both CSF samples recognized Microglial cells in the cortical biopsy. AD CSF Microglial antibodies appear to be significant in view of the increasing association between Microglia and neuro degenerative processes in AD. These findings add further support to the concept that inflammation and similar immune mechanisms may contribute to to AD pathogenesis

  483. Mochizuki A, Peterson JW, Mufson EJ, Trapp BD (1996) Amyloid load and neural elements in Alzheimer's disease and nondemented individuals with high amyloid plaque density. Exp.Neurol. 142:89-102
    Abstract: The amyloid burden and relationship between amyloid deposits and neural elements were investigated in sections of prefrontal neocortex from eight Alzheimer's disease (AD) patients and four age-matched nondemented controls with high amyloid plaque density (HPND). Computer-based image analysis revealed that the total area occupied by betaA4 immunoreactivity was significantly greater (P < 0.031) in AD (27.1%) than in HPND (14.5%) sections. The total betaA4-positive area occupied by nondiffuse plaques was significantly greater (P < 0.05) in AD (13.6%) than in HPND (5.2%) sections. The percentage of diffuse (DPs) and nondiffuse plaques (NDPs) which contained neurons, astrocytes, Microglia, dystrophic neurites, and amyloid precursor protein (APP) was also determined. The frequency of association between betaA4 and these neural elements was similar between AD and HPND cases in both diffuse and nondiffuse plaques. Forty percent of DPs in AD and HPND sections contained neuronal perikarya. Microglia, dystrophic neurites, and APP were detected in most nondiffuse plaques in both AD and HPND sections. While astrocyte cell bodies were not present in either diffuse or nondiffuse plaques, their processes were detected in most. These findings indicate that amyloid deposition and nondiffuse plaques are greater in AD than in HPND sections. The association between Microglia and nondiffuse plaques supports the hypothesis that these resident immune cells participate in aggregation and redistribution of amyloid deposits and possibly formation of dystrophic neurites

  484. Nakai M, Kawamata T, Taniguchi T, Maeda K, Tanaka C (1996) Expression of apolipoprotein E mRNA in rat Microglia. Neurosci.Lett. 211:41-44
    Abstract: Apolipoprotein E (apoE) is a major risk factor for Alzheimer disease (AD), which is the most common cause of progressive dementing illness. ApoE has been postulated to be synthesized by astrocytes and taken up by Microglia and neuronal cells. However, it remains unknown whether apoE is also produced by Microglia in the brain. We analyzed apoE mRNA expression of Microglia using a rat primary culture system. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed expression of apoE mRNA in cultured rat Microglia. By RT-in situ-PCR, Microglia showed positive staining for the PCR product of apoE mRNA. These results indicated that apoE was biosynthesized in rat Microglia. We suggest that Microglia might be one of the sources of apoE in the brain, and that apoE synthesized in Microglia might be closely related to the pathogenesis of AD

  485. Oster-Granite ML, McPhie DL, Greenan J, Neve RL (1996) Age-dependent neuronal and synaptic degeneration in mice transgenic for the C terminus of the amyloid precursor protein. J.Neurosci. 16:6732-6741
    Abstract: The molecular basis for the degeneration of neurons and the deposition of amyloid in plaques and in the cerebrovasculature in Alzheimer's disease (AD) is incompletely understood. We have proposed that one molecule common to these abnormal processes is a fragment of the Alzheimer amyloid precursor protein (APP) comprising the C-terminal 100 amino acids of this molecule (APP-C100). We tested this hypothesis by creating transgenic mice expressing APP-C100 in the brain. We report here that aging (18-28 month) APP-C100 transgenic mice exhibit profound degeneration of neurons and synapses in Ammon's horn and the dentate gyrus of the hippocampal formation. Of the 106 transgenic mice between 8 and 28 months of age that were examined, all of those older than 18 months displayed severe hippocampal degeneration. The numerous degenerating axonal profiles contained increased numbers of neurofilaments, whorls of membrane, and accumulations of debris resembling secondary lysosomes near the cell body. The dendrites of degenerating granule and pyramidal cells contained disorganized, wavy microtubules. Cerebral blood vessels had thickened refractile basal laminae, and Microglia laden with debris lay adjacent to larger venous vessels. Mice transgenic for Flag-APP-C100 (in which the hydrophilic Flag tag was fused to the N terminus of APP-C100) showed a similar degree of neurodegeneration in the hippocampal formation as early as 12 months of age. The 45 control mice displayed only occasional necrotic cells and no extensive cell degeneration in the same brain regions. These findings show that APP-C100 is capable of causing some of the neuropathological features of AD

  486. Paresce DM, Ghosh RN, Maxfield FR (1996) Microglial cells internalize aggregates of the Alzheimer's disease amyloid beta-protein via a scavenger receptor. Neuron 17:553-565
    Abstract: Microglia are immune system cells associated with Alzheimer's disease plaques containing beta-amyloid (A beta). Murine Microglia internalize microaggregates of fluorescently labeled or radioiodinated A beta peptide 1-42. Uptake was confirmed using aggregates of unlabeled A beta detected by immunofluorescence. Uptake of A beta was reduced by coincubation with excess acetyl-low density lipoprotein (Ac-LDL) or other scavenger receptor (SR) ligands, and Dil-labeled Ac-LDL uptake by Microglia was blocked by excess A beta. CHO cells transfected with class A or B SRs showed significantly enhanced uptake of A beta. These results show that Microglia express SRs that may play a significant role in the clearance of A beta plaques. Binding to SRs could activate inflammation responses that contribute to the pathology of Alzheimer's disease

  487. Roe MT, Dawson DV, Hulette CM, Einstein G, Crain BJ (1996) Microglia are not exclusively associated with plaque-rich regions of the dentate gyrus in Alzheimer's disease. J.Neuropathol.Exp.Neurol. 55:366-371
    Abstract: The functional significance of Microglia found in neuritic plaques in Alzheimer's disease (AD) remains a source of controversy. In the present study, we explored the anatomic relationships between Microglia and neuritic plaques in order to determine the potential role of Microglia in plaque formation. We chose to study the molecular layer of the hippocampal dentate gyrus, a brain region where plaques have a strong tendency to line up parallel to the adjacent granule cell layer. We found that ferritin-labeled Microglia were indeed most numerous in the same distinct band as plaques, but that Microglia were relatively more common in the outer molecular layer. The distribution of Microglia was more variable than that of plaques. Overall, Microglial cell distribution was a relatively poor predictor of plaque distribution, particularly when cases were considered individually. Thus, there must be multiple triggers for Microglial cell activation and accumulation in the AD brain, triggers which do not all necessarily lead to neuritic plaque formation

  488. Roher AE, Chaney MO, Kuo YM, Webster SD, Stine WB, Haverkamp LJ, Woods AS, Cotter RJ, Tuohy JM, Krafft GA, Bonnell BS, Emmerling MR (1996) Morphology and toxicity of Abeta-(1-42) dimer derived from neuritic and vascular amyloid deposits of Alzheimer's disease. J.Biol.Chem. 271:20631-20635
    Abstract: In the course of analyzing the chemical composition of Alzheimer's disease neuritic and vascular amyloid, we have purified stable dimeric and trimeric components of Abeta peptides. These peptides (molecular mass 9.0 and 13.5 kDa) were separated by size exclusion chromatography in the presence of 80% formic acid or 5 guanidine thiocyanate, pH 7.4. The average ratio of monomers, dimers, and trimers was 55:30:15, respectively. Similar structures were produced over time upon incubation of synthetic Abeta-(1-42) at pH 7.4. The stability of these oligomeric forms was also demonstrated by Western blot and mass spectrometry. Atomic force microscopy and electron microscopy rotary shadowing revealed that the monomers polymerized into 8-10-nm filaments, whereas the dimers generated prolate ellipsoids measuring 3-4 nm in diameter. The pathogenic effects of the dimeric Abeta-(1-40/42) were tested in cultures of rat hippocampal neuron glia cells. Only in the presence of Microglia did the dimer elicit neuronal killing. It is possible that these potentially pathogenic Abeta-(1-40/42) dimers and trimers from Alzheimer's disease amyloid represent the soluble oligomers of Abeta recently described in Alzheimer's disease brains (Kuo, Y.-M., Emmerling, M. R., Vigo-Pelfrey, C., Kasunic, T. C., Kirkpatrick, J. B., Murdoch, G. H., Ball, M. J., and Roher, A. E. (1996) J. Biol. Chem., 271, 4077-4081)

  489. Rossi F, Bianchini E (1996) Synergistic induction of nitric oxide by beta-amyloid and cytokines in astrocytes. Biochem.Biophys.Res.Commun. 225:474-478
    Abstract: The deposition of beta-amyloid peptides in the brain in form of senile plaque is the key event responsible for Alzheimer pathology. Among various mechanisms that have been proposed to explain the neurotoxicity of beta-amyloid deposits, a new one, recently identified in our laboratory, suggests that beta-amyloid peptides may be indirectly toxic for neurons by activating Microglial cells to produce NO (2). We have investigated if astrocytes, nerve cells that play an important role in many brain diseases, also might be involved in a similar mechanism of neuronal damage. The results have demonstrated that (1) beta-amyloid peptide (25-35), in the presence of IFN gamma or TNF alpha, induces the production of NO in the astrocyte cell line C6, while neither cytokine was effective per se; (2) NO generation is also synergically induced by beta-amyloid peptide (25-35) in the presence of IL-1 beta, the latter being a cytokine able to activate astrocytes per se; (3) the effect of beta-amyloid peptide (25-35) is due to the induction of the expression of the gene of inducible NO-synthase. These findings suggest that astrocytes, activated by deposited beta-amyloid peptides and cytokines, may play a role in neuronal damage via the indirect NO mechanism

  490. Sasaki A, Nakazato Y, Ogawa A, Sugihara S (1996) The immunophenotype of perivascular cells in the human brain. Pathol.Int. 46:15-23
    Abstract: The immunophenotype of perivascular cells (PC) in temporal lobe tissues obtained at autopsy in 48 patients (aged 41-88 years) was characterized using light and electron microscopic immunocytochemistry with a variety of antibodies. In all cases studied, PC bearing CD11c (Ki-M1P) and CD68 (KP1) were distributed throughout the temporal cortex. In addition to Ki-M1P and KP1, the monoclonal antibodies against major histocompatibility complex (MHC) class II antigen (Ag) (LN-3, CR3.43), anti-leucocyte common antigen (LCA), LN-5, Mac 387 were all found in PC with variable immunoreactivity. In contrast, LN-1 and OPD4 were not found in PC, although the former showed nearly constant staining of resting Microglia. Semiquantitative analysis disclosed differences in the numbers of cells labeled with the markers in the 21 normal brains (Ki-M1P > KP1 >> LCA, LN-3, LN-5 >> Mac 387). Ultrastructurally, immunoreactivity for Ki-M1P, KP1, and LN-3 was observed in PC with cytoplasm containing dense lysosomal bodies. In brains from patients with Alzheimer's type dementia, PC were seen in the wall of beta-amyloid protein-positive small vessels. However, there was no definite alteration of antigenicity in PC from AD brains compared with those from normal brains. The immunophenotype of PC was similar to that of macrophages, which were observed in the perivascular spaces and the leptomeninges in some normal and diseased brains. In contrast with PC, however, macrophages showed high incidence of labeling for some macrophage markers LN-5 and Mac 387. These findings demonstrate that PC may be a normal constituent of the adult human brain with a variable expression of monocyte/macrophages markers and MHC class II Ag and that PC could be distinguished from resting Microglia by their morphology and by their immunophenotype

  491. Schwab C, Steele JC, McGeer PL (1996) Neurofibrillary tangles of Guam parkinson-dementia are associated with reactive Microglia and complement proteins. Brain Res. 707:196-205
    Abstract: Guamanian parkinsonism-dementia, locally described as bodig, is characterized by the widespread appearance of neurofibrillary tangles in cortical and subcortical areas. These tangles have similar regional distribution and immunohistochemical profile to those found in Alzheimer disease (AD). We studied the immunohistochemical staining of these tangles, as well as those of AD, using antibodies to complement proteins and related molecules. In bodig, as in AD, extracellular tangles were intensely decorated with antibodies to C1q, C4d and C3d, but not fraction Bb of factor B, properidin or immunoglobulins. This is evidence that the classical, but not the alternative complement pathway is activated on extracellular tangles and that the activation is independent of antibodies. Immunohistochemical staining for amyloid P, an in vitro activator of complement, was remarkably similar to that for the C1q, C4d and C3d in both bodig and AD. This was not the case for beta-amyloid protein (BAP), another in vitro complement activator. Positive staining was observed in only a minority of extracellular tangles in bodig and was only rarely observed in those of AD. BAP would therefore not appear to be a candidate for activating complement on extracellular neurofibrillary tangles. Reactive Microglia and reactive astrocytes were closely associated with complement positive extracellular neurofibrillary tangles, indicating an inflammatory response similar to that seen in AD

  492. Sheng JG, Mrak RE, Griffin WS (1996) Apolipoprotein E distribution among different plaque types in Alzheimer's disease: implications for its role in plaque progression. Neuropathol.Appl.Neurobiol. 22:334-341
    Abstract: We sought to determine the pattern of ApoE immunoreactivity in mesial temporal lobe tissue from 12 Alzheimer patients, age 66-88, and to determine the distribution of this immunoreactivity among different plaque types representing hypothesized stages of plaque evolution. In these patients, the cortical area of ApoE immunoreactivity was 30% that of beta-amyloid. Only 6% of diffuse non-neuritic amyloid deposits were even weakly ApoE immunoreactive (ApoE+). This is in contrast to our previous demonstration that Microglia overexpressing interleukin-1 (IL-1) are present in most diffuse non-neuritic deposits. Eighty-three per cent of diffuse neuritic plaques and 86% of dense-core neuritic plaques were highly ApoE+, consistent with IL-1-induced astrocyte activation and synthesis of ApoE resulting in the appearance of ApoE immunoreactivity in neuritic plaques. Dense-core non-neuritic ('burned out') plaques were only rarely (6%) ApoE+. These results, together with the known trophic and toxic effects of ApoE on neurites, suggest that plaque-associated ApoE contributes to the formation of overgrown degenerating (dystrophic) neurites in plaques. However, the fact that some neuritic plaques are not ApoE+ suggests contributions by additional trophic and toxic factors. Our results are also consistent with a role for ApoE in the condensation of diffuse amyloid deposits into a beta-pleated-sheet form that occurs concomitant with dystrophic neurite formation in the neuritic beta-amyloid plaques of Alzheimer's disease

  493. Sparks DL (1996) Intraneuronal beta-amyloid immunoreactivity in the CNS. Neurobiol.Aging 17:291-299
    Abstract: The high degree of overlap in the neuropathologic outcome of Alzheimer's disease (AD), Down's Syndrome (DS), and coronary heart disease suggest a possible interrelationship. The pattern of hippocampal and cortical intraneuronal beta A4 immunoreactivity is strikingly similar in AD, DS, coronary heart disease, and two separate animal models of coronary heart disease. Cells in fascia dentata and large cortical neurons were beta A4 immunodecorated in half the AD and DS subjects studied. Similar neuronal staining occurred in half the age-matched coronary heart disease subjects, but was absent in each nonheart disease control investigated. Analogous accumulations of neuronal beta A4 immunoreactivity were induced in rabbit brain by dietary administration of high cholesterol, and this effect could be reversed by regression of the experimental diet. Decreased density (p < 0.05) and cellular staining intensity occurred after 2 weeks of control diet following 8 weeks of high cholesterol. Microgliosis accompanied the accumulation of beta A4 immunoreactivity in the cholesterol-fed rabbits and persisted after regression of the diet and decreases in neuronal beta A4 immunoreactivity. An identical pattern of neuronal beta A4 immunoreactivity was induced in the brains of adolescent pigs after acute ligation of the left anterior descending coronary artery (LAD) compared to surgical and anesthetic controls. The mean number of beta A4 immunoreactive neurons was significantly increased (p < 0.05) in the cortex and hippocampus of pigs with a ligated LAD compared to both control groups. Increased density and intensity of neuronal beta A4 immunoreactivity induced by ligation of the LAD was commensurate with the severity of the decreased cardiac output in the LAD group, but not in the anesthetic control groups with decreased cardiac output. The incidence of ALZ-50 (A68) immunoreactive neurons also increased in the ligated pigs compared to both control groups. The data suggest a neuronal origin of beta A4 immunoreactive peptide(s), which can be cleared from the brain by Microglia after severe accumulation is induced. This could indicate that reduced clearance of beta-APP metabolic by-products could contribute to a metabolic backlog and redirection of peptide processing by Microglia to extracellular deposition. Neuronal accumulation of beta A4 immunoreactivity could be due to the effect of circulating factors on brain function in both animals models. It is likely that animal models of coronary heart disease may be useful in disclosing the mechanism of SP formation and induction of ALZ-50 immunoreactivity irrespective of their pathoclinical significance

  494. Tomimoto H, Akiguchi I, Suenaga T, Nishimura M, Wakita H, Nakamura S, Kimura J (1996) Alterations of the blood-brain barrier and glial cells in white-matter lesions in cerebrovascular and Alzheimer's disease patients. Stroke 27:2069-2074
    Abstract: BACKGROUND AND PURPOSE: The underlying cause of white-matter lesions, which are frequent findings in cerebrovascular disease (CVD) and Alzheimer's disease (AD), remains uncertain. We performed immunohistochemical analysis of serum protein extravasation to investigate the function of the blood-brain barrier in white-matter lesions. METHODS: White-matter lesions were estimated by use of Kluver-Barrera staining in patients diagnosed clinicopathologically as having ischemic CVD (n = 14) and AD (n = 12) and from nonneurological control subjects (n = 6). Axonal damages were investigated by use of immunohistochemistry for amyloid protein precursor. Alteration of the blood-brain barrier was examined with fibrinogen and immunoglobulins used as markers. The numbers of HLA-DR-positive Microglia and glial fibrillary acidic protein-positive astroglia were examined comparatively. RESULTS: White-matter lesions were graded as normal (grade 0) in 14 of the 32 cases (44%), slight (grade I) in 10 cases (31%), moderate (grade II) in 6 cases (19%), and severe (grade III) in 2 cases (6%). Amyloid precursor protein was accumulated most frequently in grade II white-matter lesions. Immunohistochemistry for serum proteins labeled astroglial cell bodies and their processes, which seemed to have sequestered extravasated proteins. The groups with detectable white-matter lesions had significantly higher grading scores for fibrinogen and immunoglobulins than the control group (P < .05). Although the higher scores for serum protein extravasation were statistically significant in ischemic CVD cases (P < .05), there was no significant increase in AD cases. Activated Microglia and astroglia were more numerous in the groups with white-matter lesions in both ischemic CVD and AD cases, although this increase in the number of astroglia was not evident in regions with clasmatodendrosis. CONCLUSIONS: Dysfunction of the blood-brain barrier is more prominent in white-matter lesions seen in ischemic CVD than in AD and may have a role in the pathogenesis of cerebrovascular white-matter lesions

  495. Troncoso JC, Sukhov RR, Kawas CH, Koliatsos VE (1996) In situ labeling of dying cortical neurons in normal aging and in Alzheimer's disease: correlations with senile plaques and disease progression. J.Neuropathol.Exp.Neurol. 55:1134-1142
    Abstract: We examined the degeneration of neocortical neurons in normal aging and Alzheimer's disease (AD) using terminal transferase (TdT)-mediated deoxyuridine triphosphate (d-UTP)-biotin nick-end labeling (TUNEL), a method that identifies DNA strand breaks and constitutes a positive marker for dying neurons. TUNEL was positive in neurons, glia, and Microglial cells in AD but not in younger or age-matched cognitively characterized controls. Neuronal labeling in AD was most conspicuous in cortical layer III in the early stages of the disease and became more widespread as the disease progressed. In addition, we observed TUNEL of lamina III neurons in a subset of older subjects who had normal cognition but abundant neocortical senile plaques. In concert, the availability of a direct marker of dying neurons allows for specific correlations of cell death with other neuropathological markers as well as clinical variables. Observations from the present study suggest that the death of cortical neurons precedes the symptomatic stage of AD and evolves in parallel with the clinical progression of the disease and that there appears to be an association between the degree of cell death and the severity of senile plaques

  496. Vodovotz Y, Lucia MS, Flanders KC, Chesler L, Xie QW, Smith TW, Weidner J, Mumford R, Webber R, Nathan C, Roberts AB, Lippa CF, Sporn MB (1996) Inducible nitric oxide synthase in tangle-bearing neurons of patients with Alzheimer's disease. J.Exp.Med. 184:1425-1433
    Abstract: In Alzheimer's disease (AD), affected neurons accumulate beta amyloid protein, components of which can induce mouse Microglia to express the high-output isoform of nitric oxide synthase (NOS2) in vitro. Products of NOS2 can be neurotoxic. In mice, NOS2 is normally suppressed by transforming growth factor beta 1 (TGF-beta 1). Expression of TGF-beta 1 is decreased in brains from AD patients, a situation that might be permissive for accumulation of NOS2. Accordingly, we investigated the expression of NOS2 in patients with AD, using three monospecific antibodies: a previously described polyclonal and two new monoclonal antibodies. Neurofibrillary tangle-bearing neurons and neuropil threads contained NOS2 in brains from each of 11 AD patients ranging in age from 47 to 81 years. NOS2 was undetectable in brains from 6 control subjects aged 23-72 years, but was expressed in small amounts in 3 control subjects aged 77-87 years. Thus, human neurons can express NOS2 in vivo. The high-output pathway of NO production may contribute to pathogenesis in AD

  497. Wisniewski HM, Wegiel J, Kotula L (1996) Review. David Oppenheimer Memorial Lecture 1995: Some neuropathological aspects of Alzheimer's disease and its relevance to other disciplines. Neuropathol.Appl.Neurobiol. 22:3-11
    Abstract: Recent studies of diffuse A beta plaques point to the neurons as a source of A beta in diffuse plaques. The neuritic (primitive and classical) plaques appear to be the product of Microglia and the myocytes are the source of amyloid deposits in the meningeal and cortical vessels. Dyshoric angiopathy is associated with deposits of amyloid by perivascular cells. Fibrillization of the neuron-derived diffuse, thioflavine-negative or benign plaques is poor or undetectable by current morphological methods including ultrastructural immunocytochemistry. It appears that fibrillization depends on the length of the A beta peptides and on the presence of amyloid-associated proteins. Four genes are now tightly linked with Alzheimer's disease (AD) and they are located on chromosomes 21, 19, 14 and 1. Therefore, AD should be considered a polyaetiological disease or syndrome. There are currently five transgenic mouse models overexpressing beta-APP. There is also a myocyte tissue culture model in which both soluble and fibrillized A beta are found. The relationship between A beta and neurofibrillary pathology is not clear and the current cascade hypothesis proposing that A beta pathology drives the formulation of neurofibrillary tangles is being questioned. There is growing evidence that it is not the A beta hypothesis, but the co-existing A beta neurofibrillary tangle pathology hypothesis which will be the basis for AD neuropathology

  498. Yan SD, Chen X, Fu J, Chen M, Zhu H, Roher A, Slattery T, Zhao L, Nagashima M, Morser J, Migheli A, Nawroth P, Stern D, Schmidt AM (1996) RAGE and amyloid-beta peptide neurotoxicity in Alzheimer's disease. Nature 382:685-691
    Abstract: Amyloid-beta peptide is central to the pathology of Alzheimer's disease, because it is neurotoxic--directly by inducing oxidant stress, and indirectly by activating Microglia. A specific cell-surface acceptor site that could focus its effects on target cells has been postulated but not identified. Here we present evidence that the 'receptor for advanced glycation end products' (RAGE) is such a receptor, and that it mediates effects of the peptide on neurons and Microglia. Increased expressing of RAGE in Alzheimer's disease brain indicates that it is relevant to the pathogenesis of neuronal dysfunction and death

  499. Zielasek J, Hartung HP (1996) Molecular mechanisms of Microglial activation. Adv.Neuroimmunol. 6:191-22
    Abstract: Microglial cells are brain macrophages which serve specific functions in the defense of the central nervous system (CNS) against microorganisms, the removal of tissue debris in neurodegenerative diseases or during normal development, and in autoimmune inflammatory disorders of the brain. In cultured Microglial cells, several soluble inflammatory mediators such as cytokines and bacterial products like lipopolysaccharide (LPS) were demonstrated to induce a wide range of Microglial activities, e.g. increased phagocytosis, chemotaxis, secretion of cytokines, activation of the respiratory burst and induction of nitric oxide synthase. Since heightened Microglial activation was shown to play a role in the pathogenesis of experimental inflammatory CNS disorders, understanding the molecular mechanisms of Microglial activation may lead to new treatment strategies for neurodegenerative disorders, multiple sclerosis and bacterial or viral infections of the nervous system

  500. Akiyama H, Kondo H, Ikeda K, Arai T, Kato M, McGleer PL (1995) Immunohistochemical detection of coagulation factor XIIIa in postmortem human brain tissue. Neurosci.Lett. 202:29-32
    Abstract: Blood coagulation factor XIII is responsible for stabilizing fibrin clots by catalyzing the formation of covalent bonds between lysine amino groups and glutamine carboxyl groups. A smaller form of factor XIII called factor XIIIa (FXIIIa) occurs intracellularly in platelets, monocytes and peripheral macrophages. Using a specific antibody to FXIIIa, we detected this molecule immunohistochemically in a subpopulation of reactive Microglia and macrophages in a number of neurological disease states. These included Alzheimer's disease and other degenerative disorders. FXIIIa was also detected in capillaries and some leukocytes in both control and neurologically diseased tissue. FXIIIa is known to cross-link a variety of proteins in addition to fibrin. Its occurrence in some reactive Microglia suggests a possible role in the fundamental pathology

  501. Armstrong RA, Winsper SJ, Blair JA (1995) Hypothesis: is Alzheimer's disease a metal-induced immune disorder? Neurodegeneration. 4:107-111
    Abstract: A hypothesis that a metal-induced immune disorder may be involved in the pathogenesis of some forms of Alzheimer's disease (AD) is presented. The classical complement pathway is activated in AD and T cells and reactive Microglia appear in the brain. Studies of metal induced autoimmunity and the use of compounds containing aluminium as vaccine adjuvants suggest that metals can activate complement and can be taken up by antigen presenting cells. The consequent immune response could contribute to neuronal damage, beta-amyloid deposition and cell death. The strengths and weaknesses of this hypothesis are discussed and tests of some aspects are proposed

  502. Barnum SR (1995) Complement biosynthesis in the central nervous system. Crit Rev.Oral Biol.Med. 6:132-146
    Abstract: Complement is an important effector arm of the human immune response. Binding of proteolytic fragments derived from activation of complement by specific receptors leads to responses as diverse as inflammation, opsonization, and B-cell activation. The importance of characterizing the expression and regulation of complement in the CNS is highlighted by growing evidence that complement plays a significant role in the pathogenesis of a variety of neurological diseases, such as multiple sclerosis and Alzheimer's disease. In vitro studies have demonstrated that astrocytes, the predominant glial cell type in the brain, are capable of expressing or producing a majority of the components of the complement system. Expression of many complement proteins synthesized by astrocytes is regulated by both pro- and anti-inflammatory cytokines, many of which are also produced by several cell types in the CNS. In addition to astrocytes, ependymal cells, endothelial cells, Microglia, and neurons have recently been shown to synthesize various complement proteins or express complement receptors on their cell surfaces. Together, these studies demonstrate that several cell types throughout the brain have the potential to express complement and, in many cases, increase expression in response to mediators of the acute phase response. These studies suggest that complement may play a greater role in CNS immune responses than previously thought, and pave the way for better understanding of the dynamics of complement expression and regulation in vivo. Such understanding may lead to therapeutic manipulation of complement host defense functions in a variety of inflammatory and degenerative diseases in the CNS

  503. Cras P, Smith MA, Richey PL, Siedlak SL, Mulvihill P, Perry G (1995) Extracellular neurofibrillary tangles reflect neuronal loss and provide further evidence of extensive protein cross-linking in Alzheimer disease. Acta Neuropathol.(Berl) 89:291-295
    Abstract: In this report we quantitatively assess the numbers of intracellular and extracellular neurofibrillary tangles (NFT) in the brains of a series of individuals with Alzheimer's disease and of controls and correlate these with neuronal loss. Our data indicate that in some cases, NFT are not removed from the brain throughout the disease process. This finding, together with our previous demonstration of carbonyl-related modifications in NFT, provides additional evidence that the protein constituents of NFT are resistant to proteolytic removal, possibly as a result of extensive cross-links. Additionally, correlation between the number of NFT and neuronal loss indicates that there are at least two distinct mechanisms responsible for neuronal death in Alzheimer's disease that are directly and indirectly related to the presence of neurofibrillary pathology

  504. Das S, Potter H (1995) Expression of the Alzheimer amyloid-promoting factor antichymotrypsin is induced in human astrocytes by IL-1. Neuron 14:447-456
    Abstract: The amyloid deposits of Alzheimer's disease contain, in addition to the beta protein (A beta), lesser amounts of other proteins including the protease inhibitor alpha 1-antichymotrypsin (ACT). We have recently shown that ACT acts as a pathological chaperone, binding to the beta protein and strongly promoting its polymerization into amyloid filaments in vitro. The data of this paper show that ACT synthesis is induced in cultured human astrocytes by IL-1, a lymphokine whose expression is strongly up-regulated in Microglial cells in affected areas of Alzheimer's disease brain. Furthermore, unfractionated glial cultures containing both astrocytes and Microglia from human cortex (which develops amyloid in Alzheimer's disease) spontaneously express IL-1 and ACT as they reach confluence. In contrast, confluent mixed glial cultures similarly prepared from human cerebellum or brain stem, or from rat brain-tissues not prone to amyloid formation-do not express ACT unless supplemented with exogenous IL-1. The same regional difference in IL-1 expression by Microglia is seen in vivo in Alzheimer's disease. These results indicate that the IL-1-induced expression of ACT may help direct the region-specific production of mature amyloid filaments in the Alzheimer brain

  505. De Simone R, Giampaolo A, Giometto B, Gallo P, Levi G, Peschle C, Aloisi F (1995) The costimulatory molecule B7 is expressed on human Microglia in culture and in multiple sclerosis acute lesions. J.Neuropathol.Exp.Neurol. 54:175-187
    Abstract: B7 is a costimulatory molecule which is expressed on antigen-presenting cells and which plays a pivotal role in T cell activation and proliferation. To elucidate mechanisms regulating intracerebral immune responses, expression of B7 was examined in cultured Microglial cells and in brain tissue from control and multiple sclerosis patients. Using immunocytochemical and polymerase chain reaction techniques, we show that B7 was expressed in cultured Microglial cells from the human embryonic brain. Microglia also bound the soluble form of the B7 receptor CTLA-4 (CTLA-4-Ig). B7 gene expression and binding of anti-B7 antibodies and CTLA-4-Ig increased after treatment with interferon-gamma. B7 was not inducible in human astrocytes. Human Microglia expressed other costimulatory molecules, such as intercellular adhesion molecule-1, LFA-1 and LFA-3. In sections of multiple sclerosis brains, B7 immunoreactivity was detected on activated Microglia and infiltrating macrophages within active lesions. In chronic lesions, only perivascular cells were stained. B7 immunoreactivity was undetectable in sections from Alzheimer's disease or normal brain tissue. These data suggest that B7 may be involved in T cell activation and lesion development in multiple sclerosis and that the regulated expression of B7 on Microglia may contribute to the local stimulation of T cell proliferation and effector functions

  506. Furuta A, Price DL, Pardo CA, Troncoso JC, Xu ZS, Taniguchi N, Martin LJ (1995) Localization of superoxide dismutases in Alzheimer's disease and Down's syndrome neocortex and hippocampus. Am.J.Pathol. 146:357-367
    Abstract: Abnormalities in the cellular regulation and expression of antioxidant enzymes may have a role in mechanisms of central nervous system aging and neurodegeneration. We therefore examined, using isozyme-specific antibodies and immunohistochemistry, the localization of copper, zinc-superoxide dismutase and manganese-superoxide dismutase in the frontal and temporal neocortices and hippocampi of aged controls and individuals with Alzheimer's disease or Down's syndrome. Two different antibodies to copper, zinc-superoxide dismutase and one antibody to manganese-superoxide dismutase were evaluated by immunoblotting of homogenates of human brain before use in immunohistochemistry. The copper, zinc-superoxide dismutase antibodies recognized a single band of proteins at 16 kd. The manganese-superoxide dismutase antibody detected a single band of proteins at 25 kd. Immunohistochemically, copper, zinc-superoxide dismutase and manganese-superoxide dismutase immunoreactivities were localized predominantly to neocortical and hippocampal pyramidal neurons and scarcely seen in glial cells in controls. In Alzheimer's disease and Down's syndrome, the distributions and intensities of these two forms of superoxide dismutase immunoreactivities were different as compared with controls. Copper, zinc-superoxide dismutase was enriched in pyramidal neurons undergoing degeneration, whereas manganese-superoxide dismutase was more enriched in reactive astrocytes than in neurons. In senile plaques, copper, zinc-superoxide dismutase-positive globular structures were surrounded by astrocytes highly enriched in manganese-superoxide dismutase. By double label immunohistochemistry, some pyramidal neurons coexpressed superoxide dismutases and tau, and a few copper, zinc-superoxide dismutase-positive structures in senile plaques colocalized with tau. Amyloid cores, diffuse plaques, and Microglia scarcely showed colocalization with superoxide dismutase-positive structures. The observed changes in the cellular localization of superoxide dismutases in neocortex and hippocampus in cases of Alzheimer's disease and Down's syndrome support a role for oxidative injury in neuronal degeneration and senile plaque formation. The differential localization of copper, zinc-superoxide dismutase and manganese-superoxide dismutase in cerebral sites of degeneration suggests that cellular responses to oxidative stress is antioxidant enzyme specific and cell type specific and that these two forms of superoxide dismutase may have different functions in antioxidant mechanisms

  507. Giulian D, Haverkamp LJ, Li J, Karshin WL, Yu J, Tom D, Li X, Kirkpatrick JB (1995) Senile plaques stimulate Microglia to release a neurotoxin found in Alzheimer brain. Neurochem.Int. 27:119-137
    Abstract: Senile plaques found in the brains of patients with Alzheimer's disease (AD) are surrounded by clusters of reactive Microglia. Isolated human Microglia placed in contact with plaques in vitro are activated to release a factor which is toxic to neurons. This same neurotoxin is found in AD brain tissue and causes damage to pyramidal neurons in vivo when infused into rat hippocampus. Highest concentrations of the neurotoxin are in those brain structures most burdened by reactive Microglia, suggesting that plaque-activated cells contribute to the neuronal damage and impaired cognition seen in patients with Alzheimer's dementia

  508. Griffin WS, Sheng JG, Roberts GW, Mrak RE (1995) Interleukin-1 expression in different plaque types in Alzheimer's disease: significance in plaque evolution. J.Neuropathol.Exp.Neurol. 54:276-281
    Abstract: The histologically apparent polymorphism of plaques containing beta-amyloid in Alzheimer's disease is thought to represent different stages in plaque evolution. beta-amyloid-immunopositive plaques were classified according to the pattern of beta-amyloid distribution (diffuse vs dense-core) and the presence or absence of dystrophic beta-amyloid precursor protein-immunopositive (beta-APP+) neurites (neuritic vs non-neuritic). The potential contribution of Microglia-derived interleukin-1 (IL-1), an immune response cytokine that induces synthesis and processing of beta-APP, to the possible sequential development of these plaque types was examined through determination of the number of IL-1 alpha+ Microglia associated with each of four identified plaque types. Diffuse non-neuritic plaques had the least dense and most widely dispersed beta-amyloid, did not exhibit beta-APP+ dystrophic neurites, but most (78%) contained activated IL-1 alpha+ Microglia (2 +/- 0.2/plaque; mean +/- SEM). Diffuse neuritic plaques had more dense, but still widely dispersed beta-amyloid, displayed a profusion of beta-APP+ dystrophic neurites, and had the greatest numbers of associated activated IL-1 alpha+ Microglia (7 +/- 0.8/plaque). Dense-core neuritic plaques had both compact and diffuse beta-amyloid and had fewer IL-1 alpha+ Microglia (4 +/- 0.4/plaque). Dense-core, non-neuritic plaques had compact beta-amyloid, lacked associated diffuse beta-amyloid, and were devoid of both IL-1 alpha+ Microglia and beta-APP+ dystrophic neurites. These results suggest an important immunological component in the evolution of amyloid-containing plaques in Alzheimer's disease and further suggest that IL-1-expressing cells are necessary to initiate dystrophic neurite formation in diffuse beta-amyloid deposits.(ABSTRACT TRUNCATED AT 250 WORDS)

  509. Groom GN, Junck L, Foster NL, Frey KA, Kuhl DE (1995) PET of peripheral benzodiazepine binding sites in the microgliosis of Alzheimer's disease. J.Nucl.Med. 36:2207-2210
    Abstract: Animal and human autoradiographic studies have shown increased in vitro binding of the peripheral benzodiazepine binding site antagonist PK 11195 in areas of microgliosis, including the temporal association cortex of patients with Alzheimer's disease. To further elucidate the role of cellular inflammation and microgliosis in Alzheimer's disease during life, we used PET and [11C]PK 11195, a peripheral benzodiazepine receptor ligand known to bind avidly to Microglia. METHODS: Eight patients with a diagnosis of probable Alzheimer's disease underwent PET of the brain using [11C]PK 11195 and, for comparison, with [18F]FDG to determine cerebral glucose metabolism. Uptake of [11C]PK 11195 in various brain regions was expressed relative to that in the cerebellum and compared to values determined in one normal elderly subject and in clinically and anatomically unaffected hemispheres of seven patients with small unilateral gliomas. RESULTS: No increases in peripheral benzodiazepine binding were identified in patients with probable Alzheimer's disease, and binding was lowest in regions that were most hypometabolic. CONCLUSION: The peripheral benzodiazepine binding sites associated with microgliosis and cellular inflammation in Alzheimer's disease at postmortem are undetectable by PET using [11C]PK 11195 in patients with mild-to-moderate dementia

  510. Hartwig M (1995) Immune ageing and Alzheimer's disease. Neuroreport 6:1274-1276
    Abstract: The implications of immune ageing are considered with respect to Alzheimer's disease. In the course of immune ageing a population of activated autoreactive T cells appears which is proposed to cross the undamaged blood-brain barrier and to initiate overactivation of brain Microglia. The development of highly activated Microglia appears to be sufficient to induce the inflammatory neurotoxic process characteristic of the brain in Alzheimer's disease. The model thus emerging for sporadic Alzheimer's disease is that of a T cell-mediated chronic autoimmune syndrome following the age-dependent loss of thymic function. This view is consistent with available data and provides testable predictions

  511. Hensley K, Hall N, Subramaniam R, Cole P, Harris M, Aksenov M, Aksenova M, Gabbita SP, Wu JF, Carney JM, . (1995) Brain regional correspondence between Alzheimer's disease histopathology and biomarkers of protein oxidation. J.Neurochem. 65:2146-2156
    Abstract: Four biomarkers of neuronal protein oxidation [W/S ratio of MAL-6 spin-labeled synaptosomes, phenylhydrazine-reactive protein carbonyl content, glutamine synthetase (GS) activity, creatine kinase (CK) activity] in three brain regions [cerebellum, inferior parietal lobule (IPL), and hippocampus (HIP)] of Alzheimer's disease (AD)-demented and age-matched control subjects were assessed. These endpoints indicate that AD brain protein may be more oxidized than that of control subjects. The W/S ratios of AD hippocampal and inferior parietal synaptosomes are 30 and 46% lower, respectively, than corresponding values of tissue isolated from control brain; however, the difference between the W/S ratios of AD and control cerebellar synaptosomes is not significant. Protein carbonyl content is increased 42 and 37% in the Alzheimer's HIP and IPL regions, respectively, relative to AD cerebellum, whereas carbonyl content in control HIP and IPL is similar to that of control cerebellum. GS activity decreases an average of 27% in the AD brain; CK activity declines by 80%. The brain regional variation of these oxidation-sensitive biomarkers corresponds to established histopathological features of AD (senile plaque and neurofibrillary tangle densities) and is paralleled by an increase in immunoreactive Microglia. These data indicate that senile plaque-dense regions of the AD brain may represent environments of elevated oxidative stress

  512. Korotzer AR, Watt J, Cribbs D, Tenner AJ, Burdick D, Glabe C, Cotman CW (1995) Cultured rat Microglia express C1q and receptor for C1q: implications for amyloid effects on Microglia. Exp.Neurol. 134:214-221
    Abstract: Senile plaques, the pathological hallmark of Alzheimer's disease (AD), are associated with complement components, including C1q. Reactive Microglia appear to be involved in the later stages of plaque development. Since tissue macrophages are known to synthesize C1q, cultured rat Microglia were examined for C1q immunoreactivity. Anti-C1q staining was detected, particularly in process-bearing Microglia, indicating constitutive expression of C1q. Thus, Microglia could provide a source of C1q for plaques even before becoming reactive. Since it has been previously shown that C1q binds beta 1-42, the major constituent of senile plaques, and since beta 1-42 is toxic to Microglia in vitro, we asked if preincubation of beta 1-42 with C1q alters either metabolic indices of amyloid-induced degeneration in Microglial cultures or the formation of amyloid deposits on these cells. While electron microscopic analysis of negatively stained amyloid fibrils confirmed that pre-incubation with C1q induced the association of C1q with the fibrils, no effect of the binding of C1q to beta 1-42 on beta 1-42 toxicity in Microglia was observed. Interestingly, immunoreactivity for the C1q receptor that is known to modulate phagocytosis was found and was up-regulated in non-process-bearing Microglia by interferon-gamma. While these data exclude a role for the C1q receptor in beta 1-42 toxicity in Microglia, the observed expression and up-regulation of C1q receptor on Microglia by interferon-gamma would be consistent with a role for C1q in complement-mediated inflammatory responses in AD and as a potential activator of Microglial function in plaques

  513. Lassmann H, Bancher C, Breitschopf H, Wegiel J, Bobinski M, Jellinger K, Wisniewski HM (1995) Cell death in Alzheimer's disease evaluated by DNA fragmentation in situ. Acta Neuropathol.(Berl) 89:35-41
    Abstract: Loss of nerve cells is a hallmark of the pathology of Alzheimer's disease (AD), yet the patterns of cell death are unknown. By analyzing DNA fragmentation in situ we found evidence for cell death not only of nerve cells but also of oligodendrocytes and Microglia in AD brains. In average, 30 times more brain cells showed DNA fragmentation in AD as compared to age-matched controls. Nuclear alterations suggestive of apoptosis were rare in degenerating cells. Even though the majority of degenerating cells were not located within amyloid deposits and did not contain neurofibrillary tangles, neurons situated within areas of amyloid deposits or affected by neurofibrillary degeneration revealed a higher risk of DNA fragmentation and death than cells not exposed to these AD changes

  514. Mackenzie IR, Hao C, Munoz DG (1995) Role of Microglia in senile plaque formation. Neurobiol.Aging 16:797-804
    Abstract: To assess the role of Microglial cells in senile plaque (SP) formation, we examined the density and distribution of Microglia in the temporal neocortex of three groups of nondemented individuals, chosen to represent sequential stages of SP formation (no SP, n = 14; diffuse plaques (DP) only, n = 12; both DP and neuritic plaques (NP), n = 14) and patients with Alzheimer's disease (AD, n = 11). The mean density of Microglia was significantly greater in the AD group. In nondemented individuals, the presence of NP but not DP was associated with an increased number of Microglial cells. Most NP (91%) were focally associated with Microglial cells. DP less commonly contained Microglia, however, individuals with some NP had Microglia within a greater proportion of their DP (47%) than did those with only DP (19%). These findings suggest that: (a) Microglia are not involved in the formation of DP; (b) the presence of NP is associated with both an overall increase in Microglia and the focal aggregation of cells around NP; (c) Microglia may be locally involved in the conversion of DP into NP. This final point represents the most significant aspect of this study, providing the first quantitative evidence to support a specific role for Microglia in the formation of NP from DP

  515. McGeer PL, McGeer EG (1995) The inflammatory response system of brain: implications for therapy of Alzheimer and other neurodegenerative diseases. Brain Res.Brain Res.Rev. 21:195-218
    Abstract: Cultured brain cells are capable of generating many molecules associated with inflammatory and immune functions. They constitute the endogenous immune response system of brain. They include complement proteins and their regulators, inflammatory cytokines, acute phase reactants and many proteases and protease inhibitors. Most of the proteins are made by Microglia and astrocytes, but even neurons are producers. Many appear in association with Alzheimer disease lesions, indicating a state of chronic inflammation in Alzheimer disease brain. Such a state can apparently exist without stimulation by peripheral inflammatory mediators or the peripheral immune system. A strong inflammatory response may be autotoxic to neurons, exacerbating the fundamental pathology in Alzheimer disease and perhaps other neurological disorders. Autotoxic processes may contribute to cellular death in chronic inflammatory diseases affecting other parts of the body, suggesting the general therapeutic value of anti-inflammatory agents. With respect to Alzheimer disease, multiple epidemiological studies indicate that patients taking anti-inflammatory drugs or suffering from conditions in which such drugs are routinely used, have a decreased risk of developing Alzheimer disease. In one very preliminary clinical trial, the anti-inflammatory drug indomethacin arrested progress of the disease. New agents directed against the inflammatory processes revealed in studies of Alzheimer disease lesions may have broad therapeutic applications

  516. Meda L, Cassatella MA, Szendrei GI, Otvos L, Jr., Baron P, Villalba M, Ferrari D, Rossi F (1995) Activation of Microglial cells by beta-amyloid protein and interferon-gamma. Nature 374:647-650
    Abstract: Alzheimer's disease is the most common cause of progressive intellectual failure. The lesions that develop, called senile plaques, are extracellular deposits principally composed of insoluble aggregates of beta-amyloid protein (A beta), infiltrated by reactive Microglia and astrocytes. Although A beta, and a portion of it, the fragment 25-35 (A beta (25-35)), have been shown to exert a direct toxic effect on neurons, the role of Microglia in such neuronal injury remains unclear. Here we report a synergistic effect between A beta and interferon-gamma (IFN-gamma) in triggering the production of reactive nitrogen intermediates and tumour-necrosis factor-alpha (TNF-alpha) from Microglia. Furthermore, using co-culture experiments, we show that activation of Microglia with IFN-gamma and A beta leads to neuronal cell injury in vitro. These findings suggest that A beta and IFN-gamma activate Microglia to produce reactive nitrogen intermediates and TNF-alpha, and this may have a role in the pathogenesis of neuronal degeneration observed in ageing and Alzheimer's disease

  517. Monning U, Sandbrink R, Weidemann A, Banati RB, Masters CL, Beyreuther K (1995) Extracellular matrix influences the biogenesis of amyloid precursor protein in Microglial cells. J.Biol.Chem. 270:7104-7110
    Abstract: During axotomy studies, we discovered that the beta A4-amyloid precursor protein (APP) participates in immune responses of the central nervous system. Since Microglia constitute the main immune effector cell population of this response, we used the murine Microglial cell line BV-2 to analyze immune response-related APP expression. We show that interaction of Microglia with the extracellular environment, particularly components of the extracellular matrix, affects APP secretion as well as intracellular APP biogenesis and catabolism. Fibronectin enhanced APP secretion and decreased the level of cellular mature transmembrane APP, whereas laminin and collagen caused a decrease in secretion and an accumulation of cellular mature APP and APP fragments. Our results demonstrate that APP plays a fundamental role in the regulation of Microglial mobility, i.e. migration, initial target recognition, and binding. The decrease in APP secretion and the concomitant increase in cellular mature APP were accompanied by an accumulation of C-terminal APP fragments. Enrichment of APP and APP fragments is assumedly based on inhibition of catabolic processes that is caused by a disorganization of the actin microfilament network. These observations provide evidence that Microglia, which are closely associated with certain amyloid deposits in the brain of Alzheimer patients, can play a key role in initial events of amyloidogenesis by initiating accumulation of APP and also of amyloidogenic APP fragments in response to physiological changes upon brain injury

  518. Mrak RE, Sheng JG, Griffin WS (1995) Glial cytokines in Alzheimer's disease: review and pathogenic implications. Hum.Pathol. 26:816-823
    Abstract: The roles of activated glia and of glial cytokines in the pathogenesis of Alzheimer's disease are reviewed. Interleukin-1 (IL-1), a Microglia-derived acute phase cytokine, activates astrocytes and induces expression of the astrocyte-derived cytokine, S100 beta, which stimulates neurite growth (and thus has been implicated in neuritic plaque formation) and increases intracellular free calcium levels. Interleukin-1 also upregulates expression and processing of beta-amyloid precursor proteins (beta-APPs) (thus favoring beta-amyloid deposition) and induces expression of alpha 1-antichymotrypsin, thromboplastin, the complement protein C3, and apolipoprotein E, all of which are present in neuritic plaques. These cytokines, and the molecular and cellular events that they engender, form a complex of interactions that may be capable of self-propagation, leading to chronic overexpression of glial cytokines with neurodegenerative consequences. Self-propagation may be facilitated by means of several reinforcing feedback loops. beta-Amyloid, for instance, directly activates Microglia, thus inducing further IL-1 production, and activates the complement system, which also leads to Microglial activation with IL-1 expression. Self-propagation also could result when S100 beta-induced increases in intraneuronal free calcium levels lead to neuronal injury and death with consequent Microglial activation. Such chronic, self-propagating, cytokine-mediated molecular and cellular reactions would explain the progressive neurodegeneration and dementia of Alzheimer's disease

  519. Oken RJ (1995) Towards a unifying hypothesis of neurodegenerative diseases and a concomitant rational strategy for their prophylaxis and therapy. Med.Hypotheses 45:341-342
    Abstract: Many neurodegenerative diseases have been found to present activated Microglia, implying that immunologic processes operate which might exacerbate their basic pathologies. We consider 14 such disorders which are known or believed to exhibit these phenomena. Alzheimer's disease, the principal member of this group, has had its progression arrested in clinical trials by an antiinflammatory agent, leading us to suggest the possibility of successful prophylactic and therapeutic intervention at the immunologic level against these diseases with antiinflammatory drugs. It is further suggested that in neurodegenerative disorders of unknown etiology or pathogenesis the possible presence of activated Microglia should be investigated. Finally, the possible relevance of these concepts for schizophrenia is examined

  520. Peress NS, Perillo E (1995) Differential expression of TGF-beta 1, 2 and 3 isotypes in Alzheimer's disease: a comparative immunohistochemical study with cerebral infarction, aged human and mouse control brains. J.Neuropathol.Exp.Neurol. 54:802-811
    Abstract: Based upon the hypothesis that growth regulatory and inflammatory mechanisms participate in the pathogenesis of Alzheimer's disease, we studied cases of Alzheimer's disease for immunoreactivity to each of the three mammalian transforming growth factor beta (TGF-beta) isotypes: TGF-beta 1, TGF-beta 2, TGF-beta 3. Results were compared with those seen in control brains and in a destructive pathological process, subacute infarction. In the cases of Alzheimer's disease, TGF-beta 1 immunoreactivity was limited to neuritic profiles within senile plaques. Neuronal neurofibrillary tangles, plaque neurites, Microglia, astrocytes and macrophages expressed TGF-beta 2 immunoreactivity. TGF-beta 3 produced strikingly selective staining of Hirano bodies. In contrast, in cases with infarction, reactive astrocytes and macrophages were positive with all three antibodies. Ramified Microglia labeled selectively, as in the Alzheimer brains, with the TGF-beta 2 antibody. Subtle generalized astrocyte and Microglial immunoreactivity for TGF-beta 2 was seen in pathological and control brains. The localization of TGF-beta isotypes to the lesions of Alzheimer's disease supports the hypothesis that these cytokines may influence lesion expression. Their presence in reactive cells associated with cerebral infarction suggest that they may play a broader role in the pathogenesis of CNS disease

  521. Perlmutter LS, Barron E, Myers M, Saperia D, Chui HC (1995) Localization of amyloid P component in human brain: vascular staining patterns and association with Alzheimer's disease lesions. J.Comp Neurol. 352:92-105
    Abstract: Amyloid P component is a normal serum protein that is highly conserved across phylogeny. Although it resembles the classic acute-phase reactant C-reactive protein, and is considered to be a normal extracellular matrix component, its physiologic role in humans is unknown. Amyloid P component is also colocalized with accumulations of all recognized forms of amyloid. The present study uses light and electron microscopy to compare the cerebral localization of amyloid P component in cases with (n = 19) and without (n = 15) Alzheimer's disease (AD). In non-AD cases, amyloid P component was predominantly localized to the cerebrovasculature. Perivascular staining was observed in most cases, more so in the white than in the gray matter. In AD cases, amyloid P component was localized to all three characteristics histopathologic lesions, namely, neurofibrillary tangles, senile plaques, and amyloid angiopathy. Furthermore, in cases with prominent staining of gray matter parenchymal lesions, intravascular staining was decreased. Given the fixation and processing methods used, amyloid P component was never seen to be localized to the cerebrovascular basement membrane. These data argue against amyloid P component's postulated role as the anchor for vascular beta-amyloid deposition. Because there is no evidence for intrinsic amyloid P component production in brain, its perivascular and parenchymal distributions suggest either compromise of the blood-brain barrier or transport across vascular endothelium

  522. Sheng JG, Mrak RE, Griffin WS (1995) Microglial interleukin-1 alpha expression in brain regions in Alzheimer's disease: correlation with neuritic plaque distribution. Neuropathol.Appl.Neurobiol. 21:290-301
    Abstract: Interleukin-1 alpha-immunoreactive (IL-1 alpha+) Microglia are prominent components of neuritic plaques in Alzheimer's disease, and may be important in the evolution of neuritic plaques from diffuse amyloid deposits. Neuritic plaques show a characteristic distribution across cerebral regions and are absent in the cerebellum of patients with Alzheimer's disease. We used single- and dual-immunohistochemical labelling to investigate the possibility that the expression of IL-1 alpha is correlated with this regional distribution of neuritic (tau 2-immunoreactive, tau 2+) plaques. In Alzheimer's disease, tau 2+ neuritic plaques occurred with increasing frequency in grey matter of frontal and occipital lobes, temporal lobe, and hippocampus. There were positive correlations between the regional patterns of distribution of activated IL-1 alpha+ Microglia and tau 2+ neuritic plaques as well as between activated IL-1 alpha+ Microglia and activated astrocytes. No activated IL-1 alpha+ Microglia, tau 2+ neuritic plaques, or activated astrocytes were observed in cerebellum of these Alzheimer patients. These regional relationships between activated IL-1 alpha+ Microglia, tau 2+ neuritic plaques, and activated astrocytes, together with the established functions of IL-1, support a causal association between the overexpression of IL-1 and the evolution of beta-amyloid deposits into neuritic plaques in Alzheimer's disease

  523. Shioi J, Pangalos MN, Ripellino JA, Vassilacopoulou D, Mytilineou C, Margolis RU, Robakis NK (1995) The Alzheimer amyloid precursor proteoglycan (appican) is present in brain and is produced by astrocytes but not by neurons in primary neural cultures. J.Biol.Chem. 270:11839-11844
    Abstract: Recent studies showed that the Alzheimer amyloid precursor (APP) occurs as the core protein of a chondroitin sulfate proteoglycan (appican) in C6 glioma cells. In the present study we show that appican is present in both human and rat brain tissue. Cortical rat brain cell cultures were used to identify appican-producing cells. Soluble secreted and cell-associated appican was produced by mixed glial cultures but not by primary neuronal cultures. Among the three major glial cell types, astrocytes produced high levels of appican, while oligodendrocytes failed to produce any. Only low levels of this molecule were occasionally detected in Microglial cultures. Expression of appican in astrocyte cultures was regulated by the composition of the growth media. N2a neuroblastoma cells also produced appican; however, treatment with dibutyryl cAMP which promotes neuronal differentiation in these cells inhibited its production without inhibiting synthesis of APP. In contrast to the restricted expression of appican, APP was present in all cultures, and its production was independent of appican synthesis. Neuronal cultures produced mainly APP695 while glial cultures produced the Kunitz type protease inhibitor containing APP. The astrocyte-specific expression of appican suggests a function distinct from the function of APP. Brain appicans may play a role in the development of Alzheimer disease neuropathology

  524. Singhrao SK, Morgan BP, Neal JW, Newman GR (1995) A functional role for corpora amylacea based on evidence from complement studies. Neurodegeneration. 4:335-345
    Abstract: Few theories have been advanced for the production of corpora amylacea (CA) by the normal ageing brain and by the CNS under various neurological conditions. Proteins derived from neurons and oligodendrocytes are found in CA and to understand their origins brain tissue from patients with Alzheimer's disease (AD), multiple sclerosis (MS) and Pick's disease (PD) were tested for complement activity. All CA were immunopositive for antisera to classical pathway-specific components, the activation products C3d and the terminal complement complex (TCC), the C3 convertase regulator membrane cofactor protein (MCP) and the fluid phase regulators S-protein and clusterin. CA were immunonegative for the alternative complement pathway proteins and the complement regulators, decay accelerating factor (DAF) and CD59. Western immunoblotting of isolated solubilized CA from the same tissues demonstrated a weak band for MCP but TCC was more easily shown by immunoprecipitation. A filamentous fringe around CA, probably of astrocytic origin, was also immunopositive for complement factors. CA consist of an inert mucopolysaccharide matrix encasing ubiquitinated proteins, resulting from death of and damage to neurons, myelin and oligodendrocytes. A function of CA, therefore, could be to prevent the recognition of these immunogenic proteins by lymphocytes and Microglia and thus protect the CNS from further injury

  525. Sobel E, Davanipour Z, Sulkava R, Erkinjuntti T, Wikstrom J, Henderson VW, Buckwalter G, Bowman JD, Lee PJ (1995) Occupations with exposure to electromagnetic fields: a possible risk factor for Alzheimer's disease. Am.J.Epidemiol. 142:515-524
    Abstract: The authors present analyses of data from three independent clinical series and controls indicating an association between working in occupations with probable medium to high exposure to extremely low frequency (< 300 Hz) electromagnetic fields and sporadic Alzheimer's disease. Case-control analyses were carried out using data from patients examined at the following locations: the Department of Neurology, University of Helsinki, Helsinki, Finland, 1982-1985; the Koskela Hospital in Helsinki, 1977-1978; and the University of Southern California site of the Alzheimer's Disease Research Center of Los Angeles and Orange Counties, 1984-1993. The predominant occupations among medium (2-10 mG or > 10 mG intermittently) to high (> 10 mG or > 100 mG intermittently) exposed cases were seamstress, dressmaker, and tailor. The results appear to be independent of education, and the sex-combined odds ratios for the three series are quite homogeneous: 2.9, 3.1, and 3.0. The odds ratio for the three series analyzed together is 3.0 (p < 0.001), with a 95% confidence interval of 1.6-5.4. The odds ratio for women is 3.8 (p < 0.001), with a 95% confidence interval of 1.7-8.6. The most obvious, possibly etiologically relevant exposure is that of electromagnetic fields, which may have biologic plausibility because they may adversely influence calcium homeostasis and/or inappropriately activate immune system cells such as Microglial cells, initiating events that result in neuronal degeneration

  526. Streit WJ, Kincaid-Colton CA (1995) The brain's immune system. Sci.Am. 273:54-61

  527. Uchihara T, Kondo H, Akiyama H, Ikeda K (1995) Single-laser three-color immunolabeling of a histological section by laser scanning microscopy: application to senile plaque-related structures in post-mortem human brain tissue. J.Histochem.Cytochem. 43:103-106
    Abstract: We describe a method for observing three-color immunofluorescence simultaneously in a histological section under a confocal laser scanning microscope. In this study we investigated the spatial relationship of blood vessels, reactive Microglia, and amyloid beta-protein (A beta) deposits in post-mortem brain tissue of patients with Alzheimer's disease. HLA-DR was employed as a marker for activated Microglia and von Willebrand factor (vWF) as a marker for vascular endothelial cells. HLA-DR was labeled with R-phycoerythrin (R-PE) and vWF with fluorescein isothiocyanate. A beta-protein was immunostained with the tandem conjugate of R-PE and cyanin 5. Three images were obtained serially by scanning a tissue section with a 488-nm laser beam in combination with an appropriate emission filter for each fluorochrome. Overlaying of these three images permitted simultaneous observation of three distinct structures: activated Microglia, blood vessels, and A beta deposits. This technique provides an improved way to study the localization of three different antigens in a single tissue section

  528. Uchihara T, Kondo H, Akiyama H, Ikeda K (1995) White matter amyloid in Alzheimer's disease brain. Acta Neuropathol.(Berl) 90:51-56
    Abstract: Amyloid beta-protein (A beta) deposits in the white matter were investigated by the double immunohistochemical staining for A beta and neuritic, glial or vascular components. Reactive astroglia and neurite abnormality were absent around A beta deposits in the white matter (w-A beta) even those with a core. The association of w-A beta with blood vessels was not consistent. Aggregates of activated Microglia were found to be the sole but a consistent accompaniment of A beta deposits even in the absence of other components such as neuron, synapse, neurite abnormality and reactive astroglia, as observed in the white matter. This suggests that the aggregates of activated Microglia most likely represent one of the factors promoting the process of A beta deposition

  529. Uchihara T, Duyckaerts C, He Y, Kobayashi K, Seilhean D, Amouyel P, Hauw JJ (1995) ApoE immunoreactivity and Microglial cells in Alzheimer's disease brain. Neurosci.Lett. 195:5-8
    Abstract: The spatial relationship of apolipoprotein E (apoE)-like immunoreactivity (IR) to amyloid beta-peptide (A beta), astrocytes and Microglial cells in the brain of Alzheimer's disease was studied by double immunolabelling. Diffuse apoE-like IR was seen in A beta diffuse deposits, and markedly increased in the core of classic senile plaques. Microglial cells, sometimes immunoreactive for apoE, were frequent in areas of apoE-like IR, where they often grouped into clusters in the core of apoE-labelled senile plaques. Although astrocytic processes were seen within these senile plaques, the cell bodies were always at a distance from the core. None of these astrocytes expressed apoE-like IR. Microglial cells, some of them immunoreactive for apoE, were seen in the center of apoE-labelled senile plaques. These data suggest that Microglial cells play a more significant role than astrocytes in apoE deposition in senile plaques of Alzheimer disease

  530. van Rensburg SJ, Carstens ME, Potocnik FC, van der SG, van der Walt BJ, Taljaard JJ (1995) Transferrin C2 and Alzheimer's disease: another piece of the puzzle found? Med.Hypotheses 44:268-272
    Abstract: A significant increase in the occurrence of the transferrin C2 genetic subtype has been found in patients with Alzheimer's disease. This variant has previously been linked to diseases thought to be associated with free radical damage. We hypothesize that Alzheimer's disease is caused by free radical damage to membranes of endocytic vesicles due to defective binding of iron and aluminium by Tf C2. The aluminium binds to the membranes, creating pores, while the iron reacts with H2O2 and superoxide radicals produced by activated Microglia (brain phagocytes), to produce hydroxyl radicals (oxidative toxins), which attack the fatty acids in the membranes through these pores. In order to treat the disease successfully, it would be necessary to alleviate the multiple deficiencies caused by these toxins by constantly providing the cells with antioxidants and other essential nutrients. In addition, a drug that would stimulate the regrowth of neurons is needed

  531. Verbeek MM, Otte-Holler I, Wesseling P, Van Nostrand WE, Sorg C, Ruiter DJ, De Waal RM (1995) A lysosomal marker for activated Microglial cells involved in Alzheimer classic senile plaques. Acta Neuropathol.(Berl) 90:493-503
    Abstract: One of the major histopathological lesions in brains of patients with dementia of the Alzheimer type (DAT) is the senile plaque. Although previous studies have shown that senile plaques are often accompanied by Microglial cells, the role of these cells in DAT pathology is still unclear. In an immunohistochemical and immunoelectron microscopical analysis of DAT and control brain tissues we addressed this issue using two monoclonal antibodies (mAbs KP1 and 25F9) directed against lysosomal antigens in monocytes and macrophages. Whereas KP1 stained lysosomes in both resting and activated Microglial cells, 25F9-staining was predominantly found in lysosomes of activated Microglial cells in classic senile plaques. The number and size of 25F9-positive lysosomes in activated Microglial cells was increased compared to 25F9-staining in unaffected areas in DAT and control sections. We conclude that mAb 25F9 is a unique and useful lysosomal marker, with a higher specificity than other known markers, for activated Microglial cells associated with classic, but not with diffuse, senile plaques

  532. Walker DG, Yasuhara O, Patston PA, McGeer EG, McGeer PL (1995) Complement C1 inhibitor is produced by brain tissue and is cleaved in Alzheimer disease. Brain Res. 675:75-82
    Abstract: C1 inhibitor was identified in human brain tissue by Western blotting and by immunohistochemistry using multiple antibodies to the native protein. The presence of C1 inhibitor mRNA was identified by reverse transcriptase-polymerase chain reaction analysis of brain mRNA extracts. The mRNA was also detected in cultured postmortem human Microglia and in the IMR-32 human neuroblastoma cell line. Immunohistochemically, the native protein was detected in residual serum of capillaries and pyramidal neurons of both control and Alzheimer disease cases, as well as in occasional senile plaques of Alzheimer tissue. The reacted protein was detected on dystrophic neurites and neuropil threads in Alzheimer tissue by 4C3 monoclonal antibody, which recognizes a neoepitope following suicide inhibition. These data indicate that C1 inhibitor, a regulatory molecule controlling multiple inflammatory proteolytic cascades, is produced in normal brain. In Alzheimer disease, C1 inhibitor undergoes a prominent reaction in abnormal neuronal processes, such as dystrophic neurites and neuropil threads

  533. Wisniewski HM, Wegiel J (1995) The neuropathology of Alzheimer's disease. Neuroimaging Clin.N.Am. 5:45-57
    Abstract: This article characterizes the major pathologic changes in Alzheimer's disease (AD) brain with A beta deposition and neurofibrillary degeneration of neurons, leading to severe neuronal loss and brain atrophy. Currently, neuropathologists recognize plaques associated with fibrillar amyloid-beta and extensive damage of the neuropil (neuritic, thioflavine-S-positive or malignant plaques) and plaques that do not contain fibrils (diffuse, thioflavine-negative or benign plaques). The cellular origin of these two subclasses appears to be different: neurons seem to produce diffuse, nonfibrillar, benign plaques, whereas Microglia and perivascular cells appear to produce fibrillar deposits in brain parenchyma. Smooth muscle cells are the source of sA beta, which polymerizes in the basement membrane of leptomeningeal and cortical arteries and veins. This new classification of A beta deposits, according to the origin of amyloid, elucidates the morphologic variability of changes and opens new avenues for development of therapeutic strategies for AD

  534. Yamada T, Yoshiyama Y, Sato H, Seiki M, Shinagawa A, Takahashi M (1995) White matter Microglia produce membrane-type matrix metalloprotease, an activator of gelatinase A, in human brain tissues. Acta Neuropathol.(Berl) 90:421-424
    Abstract: Membrane-type matrix metalloprotease (MT-MMP) is an activator of gelatinase A (MMP-2), which has previously been found in carcinoma cells. We examined non-neurological and Alzheimer's disease brain tissues for MT-MMP by immunohistochemistry and in situ hybridization. The anti-MT-MMP antibodies gave positive staining of brain Microglial cells in all the brain tissues. Positively stained Microglia were found only in the white matter. The cells producing MT-MMP protein were also shown to be white matter Microglia. These results provide further evidence that activated gelatinase A, which may be a processing enzyme for degradation of beta-amyloid protein, may be produced in white matter Microglia

  535. Yamada T, Miyazaki K, Koshikawa N, Takahashi M, Akatsu H, Yamamoto T (1995) Selective localization of gelatinase A, an enzyme degrading beta-amyloid protein, in white matter Microglia and in Schwann cells. Acta Neuropathol.(Berl) 89:199-203
    Abstract: Gelatinase A is an enzyme capable of cleaving soluble beta-amyloid protein (beta AP), and may function as an alpha-secretase to produce secretory forms of amyloid precursor protein. We examined gelatinase A immunoreactivity in the brains and posterior roots of neurologically normal, lacunar stroke, Alzheimer disease (AD), amyotrophic lateral sclerosis, progressive supranuclear palsy and myasthenia gravis cases. The gelatinase A antibody stained only Microglial cells in the white matter in all the brain tissues. In AD brain, the reactive Microglia located in the center of classical senile plaques, as well as in other Microglial cells in the gray matter, showed no immunoreactivity. Gelatinase A in white matter Microglial cells may play a role in preventing local deposition of beta AP. In the posterior root, Schwann cells had positive immunoreactivity. As with other metalloproteases, gelatinase A in Schwann cells may play an antiproliferative role

  536. Yamada T, Yamanaka I (1995) Microglial localization of alpha-interferon receptor in human brain tissues. Neurosci.Lett. 189:73-76
    Abstract: The localization of the alpha-interferon receptor (alpha-IFNR) was examined in human brain tissues from neurologically normal, Alzheimer's disease (AD) and cerebral infarction cases, using one antibody (IFNaR3) which preferentially recognizes alpha 2-IFN receptor and a second antibody (anti-p40) which recognizes the soluble alpha-IFN alpha/beta receptor. In all cases, Microglial cells were stained with the antibodies. In infarct brains, macrophages were intensely labeled for alpha-IFNR. The anti-p40 antibody also showed capillary staining which might be due to residual blood plasma. On Western blots, IFNaR3 recognized only a 210 kDa alpha-IFN/receptor complex, indicating its localization in Microglial cells. The anti-p40 antibody recognized this complex as well as four other major materials of lower molecular weight. These results suggest that alpha-IFNR protein is constitutively expressed in Microglial cells

  537. Zhan SS, Sandbrink R, Beyreuther K, Schmitt HP (1995) APP with Kunitz type protease inhibitor domain (KPI) correlates with neuritic plaque density but not with cortical synaptophysin immunoreactivity in Alzheimer's disease and non-demented aged subjects: a multifactorial analysis. Clin.Neuropathol. 14:142-149
    Abstract: The formation of beta A4 amyloid protein in neuritic plaques in Alzheimer's disease (AD) and advanced age is a complex process that involves a number of both cellular and molecular mechanisms, the interrelations of which are not yet completely understood. We have examined quantitatively, in AD and aged controls an extended spectrum of amyloid plaque-related cellular and molecular factors and the cortical synaptophysin immunoreactivity (synaptic density) in order to check for interrelations between them by multifactorial analysis. In 3 cases of senile dementia of the Alzheimer type (SDAT) aged 72, 80 and 82 years, and 9 controls aged 43-88 (mean age 65) years, the cortical synaptophysin immunoreactivity was assessed, together with the numbers of neurons, astrocytes and Microglial cells, senile plaques, of tangle-bearing neurons, and the amount of beta A4 amyloid precursor protein (APP) with and without the Kunitz type serine protease inhibitor (KPI) domain. The main results were: APP including the KPI domain (KPI-APP) correlated with the number of neuritic plaques, regardless of whether they occurred in SDAT or non-demented controls. There was no significant difference in the amount of KPI-APP between SDAT and controls. Conversely, APP695 (without KPI) was significantly reduced in SDAT. KPI-APP did not correlate with the synaptophysin immunoreactivity (RGVA), while APP695 showed a significant correlation with the latter in all evaluations. It also correlated with the neuron counts, which was not true for KPI-APP. These results support previous findings indicating that KPI-APP is an important local factor for amyloid deposition in the neuritic plaques, both in AD and in non-demented aged people. On the contrary, KPI-APP does not seem to be significantly involved in the mechanisms of synaptic change outside of the plaques

  538. Aisen PS, Davis KL (1994) Inflammatory mechanisms in Alzheimer's disease: implications for therapy. Am.J.Psychiatry 151:1105-1113
    Abstract: OBJECTIVE: The purpose of this article is to review evidence that inflammatory and immune mechanisms are important in the pathophysiology of Alzheimer's disease and to suggest new treatment strategies. METHOD: The authors review the English-language literature of the last 10 years pertaining to the pathophysiology of Alzheimer's disease. RESULTS: There is ample evidence supporting the hypothesis that inflammatory and immune mechanisms are involved in tissue destruction in Alzheimer's disease. Acute phase proteins are elevated in the serum and are deposited in amyloid plaques, activated Microglial cells that stain for inflammatory cytokines accumulate around senile plaques, and complement components including the membrane attack complex are present around dystrophic neurites and neurofibrillary tangles. CONCLUSIONS: Clinical trials of anti-inflammatory/immunosuppressive drugs are necessary to determine whether alteration of these inflammatory mechanisms can slow the progression of Alzheimer's disease

  539. Akiyama H, Nishimura T, Kondo H, Ikeda K, Hayashi Y, McGeer PL (1994) Expression of the receptor for macrophage colony stimulating factor by brain Microglia and its upregulation in brains of patients with Alzheimer's disease and amyotrophic lateral sclerosis. Brain Res. 639:171-174
    Abstract: The receptor for macrophage colony stimulating factor (CSF-1) was localized immunohistochemically in postmortem human brain tissue. Microglia constitutively expressed the receptor for CSF-1 and its expression was upregulated in lesions of Alzheimer's disease and amyotrophic lateral sclerosis. The CSF-1 mediated pathway appears to be involved in the response and activation of Microglia in the central nervous system lesions

  540. Akiyama H (1994) Inflammatory response in Alzheimer's disease. Tohoku J.Exp.Med. 174:295-303
    Abstract: Microglia belong to the mononuclear phagocyte system. They represent the brain resident tissue macrophages and function as the scavenger cells in brain. In Alzheimer's disease (AD), Microglia become activated. Reactive Microglia aggregate around senile plaque beta-amyloid and neurofibrillary tangles. Heavy accumulation of these pathological debris in postmortem, however, indicates the failure or, at best, partial success of the removal. It is supposed that continued activation of Microglia in these lesions elicits a persistent inflammatory response. In fact, activation fragments of the complement system have been detected in association with beta-amyloid deposits and extracellular ghost tangles. Thrombin, a central serine protease of the coagulation pathway, is also deposited in these pathological debris. Both complements and thrombin could augment the biochemical, synthetic and phagocytic capacities of Microglia. Microglia, in turn, might play a major role for the activation of complement and coagulation systems in brain. The available evidence strongly suggests a significant similarity between the chronic inflammation and the tissue response in AD lesions, supporting a notion that the inflammatory process is a part of Alzheimer pathology

  541. Akiyama H, Ikeda K, Katoh M, McGeer EG, McGeer PL (1994) Expression of MRP14, 27E10, interferon-alpha and leukocyte common antigen by reactive Microglia in postmortem human brain tissue. J.Neuroimmunol. 50:195-201
    Abstract: We have immunohistochemically investigated the localization of a panel of leukocyte-related molecules in postmortem human brain tissue from control subjects and patients with Alzheimer's disease (AD). Microglia constitutively express leukocyte common antigens (LCA) with CD45RB determinants. Depending on the state of activation, Microglia become positive for the myeloid cell-specific calcium binding protein MRP14, LCA with CD45RO determinant, interferon-alpha, and an antigen recognized by monoclonal antibody 27E10. In AD lesions, these cells are activated in a manner consistent with a chronic inflammatory state. The results of this study have shown further parallels in protein expression between activated Microglia and activated leukocytes of the myeloid lineage

  542. Akiyama H (1994) [Alzheimer's disease and the immune system response]. Nippon Rinsho 52:2990-2994
    Abstract: Elements that belong to the natural immune system have been identified immunohistochemically in brain of patients with Alzheimer's disease (AD). Senile plaques and ghost tangles appear to be the site of chronic inflammatory response where reactive Microglia, the brain resident macrophages, play a major role. Activation of the complement, coagulation and fibrinolysis systems also occur in such lesions. Nevertheless, the accumulation of plaques and tangles in postmortem brain tissue indicates the failure of Microglia to phagocytose and degrade these pathological debris. "Frustrated" Microglia might elicit the persistent immune responses and cause the neuronal deterioration in AD. The low incidence of AD in rheumatoid arthritis patients, who have received the long-term anti-inflammatory medication, supports this notion

  543. Atanassov CL, Muller CD, Sarhan S, Knodgen B, Rebel G, Seiler N (1994) Effect of ammonia on endocytosis, cytokine production and lysosomal enzyme activity of a Microglial cell line. Res.Immunol. 145:277-288
    Abstract: Ammonia is a natural lysosomotropic compound. Concentrations of ammonium acetate > 2 mM impaired the phagocytic activity of BV-2 cells, an immortalized Microglial cell line, as was determined by the uptake of fluorescent latex microspheres of different sizes. In contrast, an increase in the uptake of fluorescent dextran was observed with the elevation in ammonium acetate concentrations. This indicates that ammonia affects phagocytotic and pinocytotic activities of BV-2 cells differently. Interferon-gamma- and polyinosinic-polycytidylic acid-stimulated secretion of IL1 alpha as well as LPS-stimulated secretion of IL6 decreased with an elevation in ammonium acetate concentrations. The constitutive secretion of IL1 alpha was not significantly affected by ammonium acetate. However, an increase in LPS-stimulated IL1 alpha secretion was observed at 10 mM and 20 mM ammonium acetate. High concentrations of ammonia affected the activity of lysosomal enzymes of the BV-2 cells. Acid phosphatase and alpha-glucosidase activities increased with the increase in ammonium acetate up to 20 mM. The activity of cathepsin D was increased at 5 mM, but decreased at higher ammonia concentrations. The effects of ammonia on Microglial functions are discussed with respect to pathogenetic mechanisms of dementia of the Alzheimer type

  544. Bernstein HG, Wiederanders B (1994) An immunohistochemical study of cathepsin E in Alzheimer-type dementia brains. Brain Res. 667:287-290
    Abstract: We studied the immunohistochemical localization of cathepsin E (cath E) in the brains of patients with Alzheimer disease (AD) and control brains. In the normal brain cathepsin E immunoreactivity was detectable in a small number (below 5%) of neocortical and hippocampal neurons. In AD brains cathepsin E antigen was revealed in most large cortical and hippocampal pyramids and in neurons of the Nuc. basalis of Meynert. Cathepsin E was also present in cerebral microvessels, Microglia, and in senile plaques. The enzyme might play roles in the process of neurodegeneration taking place in AD

  545. Cacabelos R, Alvarez XA, Fernandez-Novoa L, Franco A, Mangues R, Pellicer A, Nishimura T (1994) Brain interleukin-1 beta in Alzheimer's disease and vascular dementia. Methods Find.Exp.Clin.Pharmacol. 16:141-151
    Abstract: Recent investigations indicate that a neuroimmune reaction, associated with inflammatory mechanisms, can contribute in Alzheimer's disease (AD) to cell damage and neurodegeneration. Activation of Microglial cells, expression of immunohistochemical markers of brain immune function, the presence of complement proteins in brain tissue and changes in cytokine production have been reported in AD. We have studied the concentration of interleukin-1 beta (IL-1 beta) in different regions of the central nervous system (CNS) in post-mortem samples from patients with AD or vascular dementia (VD) and in age-matched control subjects (CS). IL-1 beta levels were significantly higher in AD than in VD or CS in the frontal cortex, parietal cortex, temporal cortex, hypothalamus, thalamus and hippocampus. The highest increases in IL-1 beta levels were observed in the frontal cortex (CS = 0.75 +/- 0.045; AD = 2.47 +/- 0.12, p < 0.001; VD = 1.52 +/- 0.078 pg/mg, p < 0.001) and hippocampus (CS = 0.71 +/- 0.042; AD = 2.63 +/- 0.19, p < 0.001; VD = 1.21 +/- 0.23 pg/mg, p < 0.01). No significant changes were detected in the occipital cortex and cerebellum in either AD or VD. These results clearly demonstrate that demented patients show a generalized increment of IL-1 beta production in the CNS, with maximum response in those brain regions where AD neuropathology is most prominent. This overall increase in cytokine production might represent an early event in the activation of a neuroimmune cascade leading to cell death and neurodegeneration in brain regions where a primary cause (e.g., genetic, toxic, vascular) facilitates the induction of resting Microglia for firing brain immune function

  546. Chao CC, Hu S, Kravitz FH, Tsang M, Anderson WR, Peterson PK (1994) Transforming growth factor-beta protects human neurons against beta-amyloid-induced injury. Mol.Chem.Neuropathol. 23:159-178
    Abstract: Deposition of amyloid fibrils in the brain is a histopathologic hallmark of Alzheimer disease (AD) and beta-amyloid protein (A beta), the principal component of amyloid fibrils, has been implicated in the neuropathogenesis of AD. In the present study, we first developed an in vitro model of A beta-induced neurodegeneration using human fetal brain-cell cultures and then tested the hypothesis that cytokines modulate A beta-induced neurodegeneration. When brain-cell cultures were exposed to A beta, marked neuronal loss (60% of neurons by microscopic assessment) and functional impairment (i.e., reduction in uptake of [3H]gamma-aminobutyric acid) were observed after 6 d of incubation. A beta-induced neurodegeneration was dose-dependent with maximal effect at 100 microM. Although interleukin (IL)-1, IL-6 and tumor necrosis factor (TNF)-alpha had a nominal effect, both the beta 1 and beta 2 isoforms of transforming growth factor-beta dose-dependently protected > 50% of neurons against A beta-induced injury. IL-4 also proved to be neuro-protective. A beta-induced neurodegeneration was accompanied by Microglial cell proliferation and enhanced release of IL-1, IL-6, and TNF-alpha. These findings are consistent with the emerging concept that AD is an inflammatory disease and may lead to new therapeutic strategies aimed at reducing A beta-induced neurotoxicity

  547. Cotton P (1994) Constellation of risks and processes seen in search for Alzheimer's clues. JAMA 271:89-91

  548. Dahlstrom A, McRae A, Polinsky R, Nee L, Sadasivan B, Ling EA (1994) Alzheimer's disease cerebrospinal fluid antibodies display selectivity for Microglia. Investigations with cell cultures and human cortical biopsies. Mol.Neurobiol. 9:41-54
    Abstract: Previous investigations demonstrated that the cerebrospinal fluid (CSF) from Alzheimer's disease (AD) patients contains antibodies that recognize specific neuronal populations in the adult rat central nervous system (CNS). These findings suggest a pathogenic role for immunological aberrations in this disorder. To determine if antibodies may provide a means to differentially diagnose the dementias, CSF from a diversified dementia population was screened against the developing rat CNS and a cell culture system. Markings produced by AD CSF were distinctly different from those of vascular dementias (VAD) against the developing rat CNS. More importantly, some AD CSF recognized amoeboid Microglia. The recognition of amoeboid Microglia by antibodies in AD CSF is particularly interesting since these cells proliferate in response to nervous system disease and also engulf debris. A cell culture technique was developed to allow the rapid screening of CSF antibodies. Patient CSF produced five different types of markings in the cell culture: Microglia, glioblasts, fibers, nonspecific, or negative. Correlations with these structures and the diagnosis of four different dementia populations revealed that, in comparison to the other groups, AD CSF displayed remarkable selectivity toward Microglial cells. Cortical biopsies from patients suspected to have AD were incubated with the patient's own CSF and that of confirmed AD patients. Both CSF samples recognized Microglial cells in the patient's cortical biopsy. The same CSF samples incubated against normal human cortical autopsy or a biopsy from a 3-mo-old child displayed negative immunoreactivity. These three approaches suggest that the presence of CSF Microglial antibodies may be a means to distinguish AD patients from other dementias. The results add further support to the widely growing concept that inflammation and similar immune mechanisms may contribute to AD pathogenesis

  549. Eikelenboom P, Zhan SS, Kamphorst W, van d, V, Rozemuller JM (1994) Cellular and substrate adhesion molecules (integrins) and their ligands in cerebral amyloid plaques in Alzheimer's disease. Virchows Arch. 424:421-427
    Abstract: Integrins belonging to different subfamilies can be identified immunohistochemically in cerebral amyloid plaques. Monoclonal antibodies against the VLA family beta 1-integrins show staining of the corona of classical amyloid plaques for beta 1, alpha 3 and alpha 6. Immunostaining reveal also the presence of collagen and laminin in the corona. Activated Microglial cells in classical plaques strongly express receptors belonging to the LeuCAM family (beta 2 integrins). The ligands ICAM and activated complement C3 are found in both amorphous and classical plaques. Vitronectin receptor (alpha v) is found in glial cells in classical plaques but its ligand vitronectin is seen in both amorphous and classical plaques. The data presented here demonstrate the presence of different cellular and substrate adhesive molecules (integrins) and their ligands in classical plaques. The findings suggest that amyloid plaques show signs of regeneration and tissue remodelling

  550. el Hachimi KH, Foncin JF (1994) Do Microglial cells phagocyte the beta/A4-amyloid senile plaque core of Alzheimer disease? C.R.Acad.Sci.III 317:445-451
    Abstract: We performed EM, immuno-EM and light microscope immunohistochemistry studies on the topographic and functional relationships between Microglial cells and amyloid senile plaque core in Alzheimer's disease. Microglial cells with cytologic characteristics of phagocytic function were associated to amyloid fibrils and to other neuropathological degenerative processes. On the periphery of the amyloid plaque core, Microglial cells contain intracytoplasmic bundles of membrane bound fibrils. These fibrils, like plaque core fibrils, are immunodecorated. Immunostaining was observed neither in secretory organelles nor in hyalaplasm. Preamyloid deposits in superficial layers were not associated to Microglial cells. These data lead us to conclude that the Microglial cells participate to phagocytosis of beta/A4 amyloid and do not secrete this substance in Alzheimer's disease

  551. Frederickson RD, Brunden KK (1994) New opportunities in AD research--roles of immunoinflammatory responses and glia. Alzheimer Dis.Assoc.Disord. 8:159-165

  552. Hartig W, Hausen D, Brauer K, Arendt T, Bigl V, Bruckner G (1994) Digoxigenin-tagged anti-GFAP and multiple labelling of human glia, vessels and beta-amyloid. Neuroreport 5:573-576
    Abstract: Cytochemical procedures for the combined demonstration of astroglia, Microglia, blood vessels and beta-amyloid in the human brain were developed. These multiple label experiments include the first adaptation of the digoxigenin-antidigoxigenin technique to immunocytochemistry by using digoxigenylated antibodies directed against the glial fibrillary acidic protein and its visualization in astrocytes with an antidigoxigenin-peroxidase conjugate and diaminobenzidine as chromogen. Furthermore, the specific labelling of Microglial cells was performed with the novel enhanced polymer one-step staining technique, non-interfering with conventional detection systems. The demonstration of spatial relationships between glial and vascular components in normal tissue and their alterations, e.g. in Alzheimer's disease, might provide insights into the time course and localization of pathological events

  553. Kimura H, Tooyama I, McGeer PL (1994) Acidic FGF expression in the surroundings of senile plaques. Tohoku J.Exp.Med. 174:279-293
    Abstract: Immunohistochemical examination of postmortem brain tissue of Alzheimer's disease revealed that acidic fibroblast growth factor (aFGF) was specifically expressed in a subpopulation of reactive astrocytes which were congregated at the margin of the senile plaque. Double immunostaining indicated that such upregulation of aFGF expression might be related to the presence of reactive Microglia rather than beta-amyloid protein deposits. Although, on the other hand, immunohistochemical staining for fibroblast growth factor receptor-1 occurred in some cortical neurons of Alzheimer's disease, the staining pattern did not differ from that in age-matched controls. Possible significance of aFGF-positive astrocytes in the surroundings of the senile plaque will be discussed in relation to receptor mediated or non-mediated mechanisms

  554. Klegeris A, Walker DG, McGeer PL (1994) Activation of macrophages by Alzheimer beta amyloid peptide. Biochem.Biophys.Res.Commun. 199:984-991
    Abstract: Microglia (brain resident macrophages) have been found to be closely associated with beta amyloid containing plaques in brain tissue affected by Alzheimer disease (AD). To investigate whether beta amyloid peptide (beta AP) may activate Microglia, the effects of synthetic beta AP (amino acids 1-40) and a subfragment (amino acids 25-35) on rat peritoneal macrophages were assessed using four different assays for activation. These peptides were compared with substance P, which has previously been shown to activate macrophages. Both beta amyloid peptides activated macrophages, as assessed by increased respiratory burst-associated oxygen consumption, by luminol-dependent chemiluminescence, and by aggregation. In addition, beta amyloid peptide (1-40) caused a significant increase in macrophage nitric oxide production, while subfragment (25-35) did not. Substance P caused significant activation as assessed by oxygen consumption and chemiluminescence, but not by aggregation or nitric oxide induction

  555. Kuiper MA, Visser JJ, Bergmans PL, Scheltens P, Wolters EC (1994) Decreased cerebrospinal fluid nitrate levels in Parkinson's disease, Alzheimer's disease and multiple system atrophy patients. J.Neurol.Sci. 121:46-49
    Abstract: Nitric oxide (NO) is a recently discovered endogenous mediator of vasodilatation, neurotransmission, and macrophage cytotoxicity. NO is thought to have a function in memory and in long-term potentiation. At high concentrations NO is neurotoxic and may play a role in neurodegeneration. NO is formed from L-arginine by the enzyme NO synthase (NOS), for which tetrahydrobiopterin (BH4) is a necessary co-factor. Alzheimer's disease (AD) and, to a lesser degree, Parkinson's disease (PD) are thought to be associated with increased Microglial activity, suggesting that NO production may be increased. Alternatively, in circumstances of reduced levels of intracellular L-arginine or BH4, NO production is diminished and neurotoxic oxygen radicals may be produced. Since BH4 is decreased in AD and PD brains, these diseases may be associated with decreased NO production. We investigated these two alternatives by measuring the NO degradation products nitrite and nitrate in cerebrospinal fluid (CSF) of PD (n = 103), AD (n = 13), and multiple system atrophy (MSA; n = 14) patients and controls (n = 20). We found for all patient groups, compared with controls, significantly decreased levels of nitrate, but not nitrite. This finding seems to indicate a decreased NO production of the central nervous system (CNS) in these neurodegenerative disorders

  556. Liberski PP (1994) Transmissible cerebral amyloidoses as a model for Alzheimer's disease. An ultrastructural perspective. Mol.Neurobiol. 8:67-77
    Abstract: Alzheimer's disease, a prototypic nontransmissible cerebral amyloidosis, has no adequate experimental model. Several pathogenetic events, however, may be modeled and accurately studied in the transmissible cerebral amyloidoses of kuru, Creutzfeldt-Jakob disease, Gerstmann-Straussler-Scheinker disease, and scrapie. The common neuropathological denominator in both types of cerebral amyloidoses is the presence of stellate kuru plaques, senile plaques, and pure neuritic plaques. These amyloid plaques consist of amyloid fibers, dystrophic neurites, and reactive astrocytes in different proportions. Microglial cells, which are regarded as amyloid producer/processor cells in Alzheimer's disease, may play the same function in the transmissible cerebral amyloidoses. In both transmissible and nontransmissible amyloidoses, the impairment of axonal transport leads to accumulation of abnormally phosphorylated cytoskeleton proteins (such as neurofilament proteins and microtubule-associated protein tau), which eventually produce dystrophic neurites observed as parts of plaque or as isolated pathological structures

  557. Liew SC, Penfold PL, Provis JM, Madigan MC, Billson FA (1994) Modulation of MHC class II expression in the absence of lymphocytic infiltrates in Alzheimer's retinae. J.Neuropathol.Exp.Neurol. 53:150-157
    Abstract: This study describes the expression of MHC class II antigens in retinal flat mounts from normal donors and patients with Alzheimer's disease (AD). We confirm previous observations of MHC class II immunoreactivity on Microglia in normal retinae, while observing insignificant levels of reactivity on endothelial cells (EC). A significantly increased level of MHC class II expression was detected in AD retinae. This increased immunoreactivity was found to occur in the absence of lymphocytic infiltrates, suggesting that the pathogenesis of AD in the retina may be distinct from that reported to occur in some regions of the brain. MHC class II expression, measured using computerized optical densitometry, appeared to be increased principally as a result of induced MHC class II immunoreactivity on EC. Ramified Microglia and perivascular macrophages, although hypertrophied, appeared to show unchanged levels of MHC class II expression. These findings are consistent with earlier suggestions that both aberrant MHC class II expression and suppressor activity of resident macrophages may restrict immune responses

  558. Maat-Schieman ML, Rozemuller AJ, van Duinen SG, Haan J, Eikelenboom P, Roos RA (1994) Microglia in diffuse plaques in hereditary cerebral hemorrhage with amyloidosis (Dutch). An immunohistochemical study. J.Neuropathol.Exp.Neurol. 53:483-491
    Abstract: In hereditary cerebral hemorrhage with amyloidosis (Dutch) (HCHWA-D) beta/A4 amyloid deposition is found in meningocortical blood vessels and in diffuse plaques in the cerebral cortex. Diffuse plaques putatively represent early stages in the formation of senile plaques. Microglia are intimately associated with congophilic plaques in Alzheimer's disease (AD), but Microglial involvement in diffuse plaque formation is controversial. Therefore, we studied the relationship between Microglia and diffuse plaques in the cerebral cortex of four patients with HCHWA-D using a panel of macrophage/Microglia markers (mAbs LCA, LeuM5, LeuM3, LN3, KP1, OKIa, CLB54, Mac1, Ki-M6, AMC30 and the lectin RCA-1). Eight AD patients, one demented Down's syndrome (DS) patient and four non-demented controls were included for comparison. In controls and HCHWA-D patients ramified or "resting" Microglia formed a reticular array in cortical gray and subcortical white matter. Microglial cells in or near HCHWA-D diffuse plaques retained their normal regular spacing and ramified morphology. In AD/DS gray matter more Microglial cells were stained than in controls and HCHWA-D patients. Intensely immunoreactive Microglia with enlarged cell bodies and short, thick processes clustered in congophilic plaques. In contrast to the resting Microglia, these "activated Microglia" strongly expressed class II major histocompatibility complex antigen, HLA-DR, and were AMC30-immunoreactive. These findings support the view that Microglia play a role in the formation of congophilic plaques but do not initiate diffuse plaque formation. Another finding in this study is the presence of strong monocyte/macrophage marker immunoreactivity in the wall of cortical congophilic blood vessels in HCHWA-D

  559. Matsuse T, Namba Y, Ikeda K, Inoue S, Hosoi T, Ouchi Y, Fukuchi Y, Orimo H (1994) Immunohistochemical and in situ hybridisation detection of adenovirus early region 1A (E1A) gene in the Microglia of human brain tissue. J.Clin.Pathol. 47:275-277
    Abstract: To investigate whether brain tissue is infected latently by adenovirus via a monocyte/Microglia-mediated entry mechanism, brain tissue resected at necropsy from seven senile subjects (five with senile dementia of Alzheimer type (SDAT) and two subjects without pathological changes) was examined for adenovirus early region 1A (E1A) gene and its expression using in situ hybridisation and immunohistochemical staining. HLA-DR positive, reactive Microglial cells in both SDAT and normal brain tissue showed positive hybridisation and immunoreactive expression of adenovirus E1A. Thus there may be monocyte/Microglia-mediated entry of adenovirus in the central nervous system which would be a novel and presumably common interaction between brain tissue and adenovirus

  560. McGeer PL, Walker DG, Akiyama H, Yasuhara O, McGeer EG (1994) Involvement of Microglia in Alzheimer's disease. Neuropathol.Appl.Neurobiol. 20:191-192

  561. McGeer PL, Klegeris A, Walker DG, Yasuhara O, McGeer EG (1994) Pathological proteins in senile plaques. Tohoku J.Exp.Med. 174:269-277
    Abstract: The beta-amyloid protein deposits of Alzheimer disease, whether in diffuse or consoliated form, are an agglomeration of many extracellular proteins. At least 35 have been reported as components of senile plaques, most of which also occur in diffuse deposits. More than half of these proteins are directly associated with the immune system. Since diffuse deposits are believed to be the precursors of senile plaques, it is important to define the precise molecular events that lead to the transition. Diffuse deposits share with senile plaques the presence of opsonizing components of complement, the complement activators beta-amyloid protein, amyloid P, thrombin, and apolipoprotein E. However, senile plaques contain, in addition, dystrophic neurites, agglomerates of activated Microglia, components of the membrane attack complex, and the inhibitors of the membrane attack complex, clusterin, protectin and vitronectin. Microglial cells are professional phagocytes which possess the respiratory burst apparatus when activated. It produces extracellular superoxide molecules which can then form additional toxic products such as hydrogen peroxide and hydroxyl free radicals. It has long been known that opsonized zymosan is a powerful activator of the respiratory burst system. We found this activation could be inhibited by antibodies to complement receptors in the nanomolar range. Dapsone and indomethacin, two antiinflammatory agents that may have therapeutic potential in Alzheimer disease, were weakly inhibitory (10(-4) M range).(ABSTRACT TRUNCATED AT 250 WORDS)

  562. McGeer PL, Rogers J, McGeer EG (1994) Neuroimmune mechanisms in Alzheimer disease pathogenesis. Alzheimer Dis.Assoc.Disord. 8:149-158
    Abstract: Lesions in Alzheimer disease are characterized by the assembly of a variety of cells and proteins associated with the immune system. Activated Microglia express high levels of major histocompatibility complex glycoproteins and receptors for complement. Small numbers of T lymphocytes infiltrate tissue. Proteins of the classical complement pathway are closely connected with beta-amyloid deposits. beta-Amyloid protein binds C1q in vitro and activates the pathway. The membrane attack complex of complement, as well as proteins that defend against that complex, colocalize with dystrophic neurites. These data imply that an autodestructive process is occurring in Alzheimer disease, that overactive Microglia might be responsible, and that antiinflammatory drugs might be an effective form of therapy

  563. McRae A, Rudolphi KA, Schubert P (1994) Propentosylline depresses amyloid and Alzheimer's CSF Microglial antigens after ischaemia. Neuroreport 5:1193-1196
    Abstract: In the gerbil hippocampus activated Microglial antigens are intensely stained by cerebrospinal fluid from patients with Alzheimer's disease (AD-CSF), OX18 and the amyloid precursor protein (beta-APP) up to 14 days after ischaemia. Propentosylline (PPF), which facilitates the adenosine A2 receptor action, has been shown to be neuroprotective, to depress O2- radical formation in macrophages and to interfere with the generation of phagocytotic macrophages from cultivated Microglial cells. In this report we tested in ischaemic gerbils whether PPF treatment influences the potential neurotoxic properties of Microglia. Daily post-treatment with PPF, started 24 h after ischaemia, depressed the immunostaining of activated Microglia by AD-CSF, OX18 and APP in the hippocampus. Thus, PPF may protect against Microglia-related brain damage

  564. Morris CM, Kerwin JM, Edwardson JA (1994) Non-haem iron histochemistry of the normal and Alzheimer's disease hippocampus. Neurodegeneration. 3:267-275
    Abstract: Increased free radical production may occur in Alzheimer's disease (AD). In view of the central role of iron in free radical reactions we have investigated the distribution of non-haem iron in the hippocampal formation in normal control individuals and in patients with AD. In controls, non-haem iron was principally associated with glial elements and the neuropil, with highest levels in the stratum radiatum/lacunosum, fimbria, alveus and oriens layers. Except for the subiculum, the pyramidal cell layers and the granule cell layer showed little or no non-haem iron staining. Intensity of staining was in the order of subiculum >> CA2 and adjacent regions of CA3 > CA4 > the remainder of CA3 > CA1. In the hippocampus in AD, iron was associated with cells containing neurofibrillary tangles (NFT) and was present in glial cells and neurites of senile plaques (SP). These findings were most pronounced in CA1 pyramidal cell layer and subicular complex although not all NFT or SP were stained. Since the NFT and SP staining for non-haem iron appears to be associated with glial cells, the association of non-haem iron with the pathological stigmata of AD may be a secondary response of glial cells, in particular Microglia, to neuronal damage

  565. Munch G, Taneli Y, Schraven E, Schindler U, Schinzel R, Palm D, Riederer P (1994) The cognition-enhancing drug tenilsetam is an inhibitor of protein crosslinking by advanced glycosylation. J.Neural Transm.Park Dis.Dement.Sect. 8:193-208
    Abstract: Non-enzymatic glycosylation of proteins, also called Maillard reaction, which occurs at an accelerated rate in diabetes, can lead to the formation of advanced glycosylation endproducts (AGEs). Tenilsetam (CAS 997: (+/-)-3-(2-thienyl)-2-piperazinone), a cognition-enhancing drug successfully used for treatment of patients suffering from Alzheimer's disease, when included in the Maillard reaction apparently inhibits protein crosslinking by AGEs in vitro. According to the mechanism proposed, Tenilsetam acts via covalent attachment to glycated proteins, thus blocking the reactive