PROJECT SUMMARY As the population ages, Alzheimer's disease and dementia are becoming a public health crisis. In our initial cycle, the Vanderbilt Memory & Aging Project was established to examine cardiovascular function in relation to structural neuroimaging changes and cognition. We also tested whether associations were more prominent in clinically symptomatic individuals. We successfully enrolled several hundred participants age 60 and older, our data successfully supported multiple training grant opportunities (e.g., National Research Service Awards, Career Development Awards), and we published numerous papers. Our results suggest subclinical cardiovascular changes relate to worse cognition, white matter changes, and cerebral atrophy, especially in the hippocampus and other cortical regions primarily affected in Alzheimer's disease. Evidence to date supports our central hypothesis that well-established homeostatic mechanisms designed to protect cerebral blood supply become less effective with age, altering the integrity of cerebral hemodynamics, and lowering the threshold for neurodegenerative and cognitive changes. Interestingly, our preliminary associations between subclinical cardiovascular integrity and cerebral hemodynamics are stronger among carriers of the apolipoprotein E ε4 (APOE-ε4) allele, an Alzheimer's disease genetic risk factor. Furthermore, findings are more prominent in cognitively unimpaired participants, suggesting subtle cardiac hemodynamic changes may act as an underrecognized precipitating contributor of neurodegeneration and corresponding cognitive decline, distinct from the exacerbating effects of overt cerebrovascular disease. In the next cycle, we propose to better characterize underlying mechanisms linking early cardiac hemodynamic changes to abnormal brain aging in cognitively unimpaired participants, and test whether APOE-ε4 moderates the effect of vascular damage on brain health. We will follow the existing cohort and supplement it with enrollment of several hundred cognitively unimpaired participants to increase statistical power for more comprehensive analyses. The new participants will complete serial longitudinal assessments with identical procedures plus lumbar puncture for cerebrospinal fluid acquisition. Innovative translational efforts leveraging sophisticated neuroimaging and molecular biomarkers are critical to better detect early, asymptomatic cardiac hemodynamic changes, which may be more influential in initiating downstream cerebrovascular and neurodegenerative processes than previously recognized.
