Our group has previously studied the brains of some unique individuals who are able to tolerate robust amounts of Alzheimer's pathological lesions (amyloid plaques and neurofibrillary tangles) without experiencing dementia while alive. These rare resilient cases do not demonstrate the patterns of neuronal/synaptic loss that are normally found in the brains of typical demented Alzheimer's patients. Moreover, they exhibit decreased astrocyte and microglial activation markers GFAP and CD68, suggesting that a suppressed neuroinflammatory response may be implicated in human brain resilience to Alzheimer's pathology. In the present work, we used a multiplexed immunoassay to profile a panel of 27 cytokines in the brains of controls, typical demented Alzheimer's cases, and two groups of resilient cases, which possessed pathology consistent with either high probability (HP, Braak stage V-VI and CERAD 2-3) or intermediate probability (IP, Braak state III-IV and CERAD 1-3) of Alzheimer's disease in the absence of dementia. We used a multivariate partial least squares regression approach to study differences in cytokine expression between resilient cases and both Alzheimer's and control cases. Our analysis identified distinct profiles of cytokines in the entorhinal cortex (one of the earliest and most severely affected brain regions in Alzheimer's disease) that are up-regulated in both HP and IP resilient cases relative to Alzheimer's and control cases. These cytokines, including IL-1β, IL-6, IL-13, and IL-4 in HP resilient cases and IL-6, IL-10, and IP-10 in IP resilient cases, delineate differential inflammatory activity in brains resilient to Alzheimer's pathology compared to Alzheimer's cases. Of note, these cytokines all have been associated with pathogen clearance and/or the resolution of inflammation. Moreover, our analysis in the superior temporal sulcus (a multimodal association cortex that consistently accumulates Alzheimer's pathology at later stages of the disease along with overt symptoms of dementia) revealed increased expression of neurotrophic factors, such as PDGF-bb and basic FGF in resilient compared to AD cases. The same region also had reduced expression of chemokines associated with microglial recruitment, including MCP-1 in HP resilient cases and MIP-1α in IP resilient cases compared to AD. Altogether, our data suggest that different patterns of cytokine expression exist in the brains of resilient and Alzheimer's cases, link these differences to reduced glial activation, increased neuronal survival and preserved cognition in resilient cases, and reveal specific cytokine targets that may prove relevant to the identification of novel mechanisms of brain resiliency to Alzheimer's pathology.
Pubmed ID: 30336198 RIS Download
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THIS RESOURCE IS NO LONGER IN SERVICE. Documented on January 4, 2023.Consortium that developed brief, standardized and reliable procedures for the evaluation and diagnosis of patients with Alzheimer's disease (AD) and other dementias of the elderly. These procedures included data forms, flipbooks, guidebooks, brochures, instruction manuals and demonstration tapes, which are now available for purchase. The CERAD assessment material can be used for research purposes as well as for patient care. CERAD has developed several basic standardized instruments, each consisting of brief forms designed to gather data on normal persons as well as on cognitively impaired or behaviorally disturbed individuals. Such data permit the identification of dementia based on clinical, neuropsychological, behavioral or neuropathological criteria. Staff at participating CERAD sites were trained and certified to administer the assessment instruments and to evaluate the subjects enrolled in the study. Cases and controls were evaluated at entry and annually thereafter including (when possible) autopsy examination of the brain to track the natural progression of AD and to obtain neuropathological confirmation of the clinical diagnosis. The CERAD database has become a major resource for research in Alzheimer's disease. It contains longitudinal data for periods as long as seven years on the natural progression of the disorder as well as information on clinical and neuropsychological changes and neuropathological manifestations.
View all literature mentionsA research center associated with the University of Pittsburgh that specializes in the diagnosis of Alzheimer's disease and related disorders. The overall objective of the ADRC is to study the pathophysiology of Alzheimer's disease, with the aim of improving the reliability of diagnosis of Alzheimer's and developing effective treatment strategies. Current research foci emphasize neuropsychiatry and neuropsychology, molecular genetics and epidemiology, basic neuroscience, and structural and functional imaging that aid in the diagnosis and treatment of Alzheimer's disease. Specific services at the ADRC include: comprehensive diagnostic evaluation of patients with suspected Alzheimer's disease and other forms of dementia; evaluation of memory, language, judgment, and other cognitive abilities; and education and counseling for patients and families.
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