Microbial Impact on NeuroDegeneration in Alzheimer's Dementia: MIND-AD

阿尔茨海默病是对公众健康的主要威胁。由于阿尔茨海默病无法治愈，因此至关重要的是 确定其可改变的风险因素，以减少其负担。尽管初步证据显示 由于它的可解释性，相对较少关注常见感染在阿尔茨海默病中的作用 病因学我们建议调查感染与常见病原体-单纯疱疹的关系 1型和2型病毒、巨细胞病毒、EB病毒、刚地弓形虫-在约25天内测量4次 年和SARS-CoV-2（导致COVID-19的病毒），伴有：（a）认知能力下降，并判定为轻度 认知障碍（MCI）和痴呆诊断;（B）阿尔茨海默病的血浆生物标志物;和（c） 生理老化的标志物（端粒缩短、细胞周期蛋白依赖性激酶抑制剂p16 INK 4a、血浆来源的 衰老相关的分泌表型和表观遗传钟）。我们还将探讨性，老年痴呆症 疾病风险基因和与压力相关的暴露（精神障碍及其症状，压力性生活事件， 和睡眠不好）作为调节剂，放大了不良感染引起的认知，大脑健康和 生理老化结果。包括病毒特异性CD 8 T细胞分化与抗体组合 在同一个体中连续测量的水平将使我们能够区分长期感染和 重新激活，并评估感染过程和对感染的免疫应答对 我们的成果。衰老相关的分泌表型将指出新的衰老途径， 感染影响大脑健康。我们将利用现有数据并从以下方面收集新数据来实现这一目标： 参与巴尔的摩流行病学集水区（ECA）研究随访的参与者， 对>35岁的患者进行5次评估（平均年龄= 70岁，范围58-100岁）。已经采集了血液样本 在ECA中，在约25年的时间内，我们将采集额外的血液样本，以获得感染状态， 四个时间点，提供了一个难得的机会来量化暴露时间和潜伏感染的再激活 与认知和功能衰退以及阿尔茨海默病生物标志物和潜在途径有关。的 拟议研究的主要指标目前正在非洲经委会完成第5波数据收集，包括采取措施 认知和功能下降，裁定MCI和痴呆诊断，细胞衰老和全基因组 遗传学和表观遗传学分析。我们在ECA中的初步数据将感兴趣的常见病原体与较低的 载脂蛋白E基因型对认知表现和提示效应的影响。我们的团队由 认知老化和阿尔茨海默氏病、神经病毒学、神经心理学、阿尔茨海默氏病方面的专家 生物标志物，遗传学和表观遗传学，以及衰老生物学。结果将阐明 常见的感染会增加患阿尔茨海默病和相关痴呆症的风险，因为这项工作是 在纵向队列中进行，它将阐明机制，确定调节剂和候选途径 这是在下降之前，从而为未来的预防，也许是治疗，努力提供信息。

Alzheimer’s disease is a major threat to public health. Because Alzheimer’s disease has no cure, it is critical to identify its modifiable risk factors that can be targeted to reduce its burden. Although initial evidence suggests its plausibility, relatively little attention has been paid to the role of common infections in Alzheimer’s disease etiology. We propose to investigate the association of infection with common pathogens—Herpes Simplex Virus Types 1 and 2, Cytomegalovirus, Epstein-Barr Virus, Toxoplasma gondii—measured four times over ~25 years, and SARS-CoV-2 (the virus that causes COVID-19), with: (a) cognitive decline, and adjudicated mild cognitive impairment (MCI) and dementia diagnoses; (b) plasma biomarkers of Alzheimer’s disease; and (c) markers of physiological aging (telomere shortening, cyclin-dependent kinase inhibitor p16INK4a, plasma-derived senescence-associated secretory phenotypes, and epigenetic clocks). We will also explore sex, Alzheimer’s disease risk genes, and stress-related exposures (mental disorders and their symptoms, stressful life events, and poor sleep) as moderators that amplify the risk of adverse infection-induced cognitive, brain health, and physiological aging outcomes. Inclusion of viral specific CD8 T-cell differentiation in combination with antibody levels measured serially in the same individuals will allow us to distinguish between long-term infections and reactivation and to evaluate the influence of the course of both infection and immune response to infection, on our outcomes. Senescence-associated secretory phenotypes will point to novel senescent pathways by which infections affect brain health. We will accomplish this using existing data and collecting new data from participants in the Baltimore Epidemiological Catchment Area (ECA) Study Follow-up, which has been assessed five times for >35 years (mean age = 70 years, range 58-100). Blood specimens have been collected three times over ~25 years in the ECA, and we will collect an additional blood draw to obtain infection status at four time points, providing a rare opportunity to quantify timing of exposure and reactivation of latent infections in relation to cognitive and functional decline and Alzheimer’s disease biomarkers and potential pathways. The MPIs of the proposed study are currently completing Wave 5 of data collection in the ECA, including measures of cognitive and functional decline, adjudicated MCI and dementia diagnoses, cellular aging and genome-wide genetic and epigenetics assays. Our preliminary data in the ECA link common pathogens of interest with lower cognitive performance and suggest effect modification by apolipoprotein E genotype. Our team consists of experts in cognitive aging and Alzheimer’s disease, neurovirology, neuropsychology, Alzheimer’s disease biomarkers, genetics and epigenetics, and the biology of aging. Results will clarify the extent to which common infections increase the risk for Alzheimer’s disease and related dementias, and because this work is performed in a longitudinal cohort, it will elucidate mechanisms, identify moderators and candidate pathways which precede decline, thus informing future preventive, and perhaps therapeutic, efforts.