Medicine and Health Sciences Commons^™

Diversity In Alzheimer's Disease Drug Trials: The Importance Of Eligibility Criteria, Sanne Franzen, Jade Emily Smith, Esther Van Den Berg, Monica Rivera Mindt, Rozemarijn L. Van Bruchem-Visser, Erin L. Abner, Lon S. Schneider, Niels D. Prins, Ganesh M. Babulal, Janne M. Papma

Sanders-Brown Center on Aging Faculty Publications

INTRODUCTION: To generalize safety and efficacy findings, it is essential that diverse populations are well represented in Alzheimer's disease (AD) drug trials. In this review, we aimed to investigate participant diversity in disease-modifying AD trials over time, and the frequencies of participant eligibility criteria.

METHODS: A systematic review was performed using Medline, Embase, the Cochrane Library, and Clinicaltrials.gov, identifying 2247 records.

RESULTS: In the 101 included AD trials, participants were predominantly White (median percentage: 94.7%, interquartile range: 81.0-96.7%); and this percentage showed no significant increase or decrease over time (2001-2019). Eligibility criteria such as exclusion of persons with psychiatric illness …

Water Exchange Rate Across The Blood-Brain Barrier Is Associated With Csf Amyloid-Β 42 In Healthy Older Adults, Brian T. Gold, Xingfeng Shao, Tiffany L. Sudduth, Gregory A. Jicha, Donna M. Wilcock, Elayna R. Seago, Danny J. J. Wang

Sanders-Brown Center on Aging Faculty Publications

INTRODUCTION: We tested if water exchange across the blood-brain barrier (BBB), estimated with a noninvasive magnetic resonance imaging (MRI) technique, is associated with cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) and neuropsychological function.

METHODS: Forty cognitively normal older adults (67–86 years old) were scanned with diffusion‐prepared, arterial spin labeling (DP‐ASL), which estimates water exchange rate across the BBB (k_w). Participants also underwent CSF draw and neuropsychological testing. Multiple linear regression models were run with kw as a predictor of CSF concentrations and neuropsychological scores.

RESULTS: In multiple brain regions, BBB kw was positively associated with CSF amyloid …

Distribution Of Microglial Phenotypes As A Function Of Age And Alzheimer's Disease Neuropathology In The Brains Of People With Down Syndrome, Alessandra C. Martini, Alex M. Helman, Katie L. Mccarty, Ira T. Lott, Eric Doran, Frederick A. Schmitt, Elizabeth Head

Sanders-Brown Center on Aging Faculty Publications

Introduction: Microglial cells play an important role in the development of Alzheimer's disease (AD). People with Down syndrome (DS) inevitably develop AD neuropathology (DSAD) by 40 years of age. We characterized the distribution of different microglial phenotypes in the brains of people with DS and DSAD.

Methods: Autopsy tissue from the posterior cingulate cortex (PCC) from people with DS, DSAD, and neurotypical controls was immunostained with the microglial marker Iba1 to assess five microglia morphological types.

Results: Individuals with DS have more hypertrophic microglial cells in their white matter. In the gray matter, individuals with DSAD had significantly fewer ramified …

Feasibility Of Dual-Task Gait To Estimate Alzheimer's Related Cognitive Decline In Down Syndrome, Kathryn L. Van Pelt, Lisa Mason Koehl, Allison M. Caban-Holt, Amelia J. Anderson-Mooney, Elizabeth Head, Frederick A. Schmitt

Sanders-Brown Center on Aging Faculty Publications

Introduction: The striatum and frontal lobes have been shown to have early Alzheimer's disease (AD) neuropathology and are critical for motor and cognitive function. We hypothesized gait would be associated with early-stage dementia in Down syndrome (DS), a cohort at risk for AD.

Methods: Twenty-eight participants with DS were enrolled in the study. Participants walked at their self-selected pace and while completing a dual task (counting, obstacle, or counting+obstacle).

Results: All participants were able to complete the self-paced condition and 78.57-96.42% completed the dual-task conditions. There was a trend for greater dual-task effects on gait velocity based on dementia diagnosis. …

Will "Social Distancing" Lead To Future "Research Distancing": A Reflection On Covid-19 Impacts On Alzheimer's Disease Research, Shoshana H. Bardach, Allison K. Gibson, Elizabeth K. Rhodus, Gregory A. Jicha

Sanders-Brown Center on Aging Faculty Publications

Coronavirus disease 19 (COVID-19) has dramatically altered everyday life, including the field of Alzheimer's disease (AD) research. This perspective article explores some of the ways in which COVID-19 has already impacted the field, anticipates some of the long-lasting effects, and explores strategies for addressing current and future needs. Areas of impact include study integrity, regulatory and industry issues, and participant engagement. Proposed strategies for addressing these challenges include analytic methods to deal with large degrees of missing data and development of patient-centered, user-friendly, remote data collection tools and assessments. We also highlight the importance of maintaining participant well-being as a …

Diabetes Is Associated With Cerebrovascular But Not Alzheimer's Disease Neuropathology, Erin L. Abner, Peter T. Nelson, Richard J. Kryscio, Frederick A. Schmitt, David W. Fardo, Randall L. Woltjer, Nigel J. Cairns, Lei Yu, Hiroko H. Dodge, Chengjie Xiong, Kamal Masaki, Suzanne L. Tyas, David A. Bennett, Julie A. Schneider, Zoe Arvanitakis

Sanders-Brown Center on Aging Faculty Publications

INTRODUCTION: The relationship of diabetes to specific neuropathologic causes of dementia is incompletely understood.

METHODS: We used logistic regression to evaluate the association between diabetes and infarcts, Braak neurofibrillary tangle stage, and neuritic plaque score in 2365 autopsied persons. In a subset of >1300 persons with available cognitive data, we examined the association between diabetes and cognition using Poisson regression.

RESULTS: Diabetes increased odds of brain infarcts (odds ratio [OR] = 1.57, P < .0001), specifically lacunes (OR = 1.71, P < .0001), but not Alzheimer's disease neuropathology. Diabetes plus infarcts was associated with lower cognitive scores at end of life than infarcts or diabetes alone, and diabetes plus high level of Alzheimer's neuropathologic changes was associated with lower mini-mental state examination scores than the pathology alone.

DISCUSSION: This study supports the conclusions that diabetes increases the risk of cerebrovascular but not Alzheimer's disease pathology, and at least some of diabetes' relationship to …

Plasma Neuronal Exosomal Levels Of Alzheimer's Disease Biomarkers In Normal Aging, Erin L. Abner, Gregory A. Jicha, Leslie M. Shaw, John Q. Trojanowski, Edward J. Goetzl

Sanders-Brown Center on Aging Faculty Publications

Plasma neuronal exosomal levels of pathogenic Alzheimer's disease (AD) proteins, cellular survival factors, and lysosomal proteins distinguish AD patients from control subjects, but changes in these exosomal proteins associated with normal aging have not been described for cognitively intact subjects. Plasma neuronal exosomal levels of P-T181-tau, P-S396-tau, Aβ_1-42, cathepsin D, repressor element 1-silencing transcription factor, and neurogranin were quantified longitudinally in cognitively intact older adults using two samples collected at 3- to 11-year intervals. Except for P-S396-tau, exosomal protein levels changed significantly with aging, but were largely outside the range observed in AD patients.