%0 Journal Article %J J Alzheimers Dis %D 2018 %T Circulating Progenitor Cells Correlate with Memory, Posterior Cortical Thickness, and Hippocampal Perfusion. %A Nation, Daniel A %A Tan, Alick %A Dutt, Shubir %A McIntosh, Elissa C %A Yew, Belinda %A Ho, Jean K %A Blanken, Anna E %A Jang, Jung Yun %A Rodgers, Kathleen E %A Gaubert, Aimée %K Aged %K Aged, 80 and over %K Antigens, CD %K Apolipoproteins E %K Cerebral Cortex %K Cognitive Dysfunction %K Female %K Flow Cytometry %K Hippocampus %K Humans %K Image Processing, Computer-Assisted %K Magnetic Resonance Imaging %K Male %K Middle Aged %K Neuropsychological Tests %K Perfusion %K Stem Cells %K White Matter %X

BACKGROUND: Bone marrow-derived progenitor cells survey the vasculature and home to sites of tissue injury where they can promote repair and regeneration. It has been hypothesized that these cells may play a protective role neurodegenerative and vascular cognitive impairment.

OBJECTIVE: To evaluate progenitor cell levels in older adults with and without mild cognitive impairment (MCI), and to relate circulating levels to memory, brain volume, white matter lesion volume, and cerebral perfusion.

METHOD: Thirty-two older adults, free of stroke and cardiovascular disease, were recruited from the community and evaluated for diagnosis of MCI versus cognitively normal (CN). Participants underwent brain MRI and blood samples were taken to quantify progenitor reserve using flow cytometry (CD34+, CD34+CD133+, and CD34+CD133+CD309+ cells).

RESULTS: Participants with MCI (n = 10) exhibited depletion of all CPC markers relative to those who were CN (n = 22), after controlling for age, sex, and education. Post-hoc age, sex, and education matched comparisons (n = 10 MCI, n = 10 CN) also revealed the same pattern of results. Depletion of CD34+ cells correlated with memory performance, left posterior cortical thickness, and bilateral hippocampal perfusion. Participants exhibited low levels of vascular risk and white matter lesion burden that did not correlate with progenitor levels.

CONCLUSIONS: Circulating progenitor cells are associated with cognitive impairment, memory, cortical atrophy, and hippocampal perfusion. We hypothesize that progenitor depletion contributes to, or is triggered by, cognitive decline and cortical atrophy. Further study of progenitor cell depletion in older adults may benefit efforts to prevent or delay dementia.

%B J Alzheimers Dis %V 61 %P 91-101 %8 2018 %G eng %N 1 %1 http://www.ncbi.nlm.nih.gov/pubmed/29103037?dopt=Abstract %R 10.3233/JAD-170587 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Older Adults Taking AT1-Receptor Blockers Exhibit Reduced Cerebral Amyloid Retention. %A Nation, Daniel A %A Ho, Jean %A Yew, Belinda %K Aged %K Aged, 80 and over %K Aging %K Amyloid beta-Peptides %K Angiotensin Receptor Antagonists %K Antihypertensive Agents %K Chi-Square Distribution %K Cross-Sectional Studies %K Dementia %K Female %K Humans %K Longitudinal Studies %K Male %K Middle Aged %K Peptide Fragments %K Psychiatric Status Rating Scales %K Regression Analysis %K tau Proteins %K Time Factors %X

BACKGROUND: Evidence suggests that angiotensin II AT1-receptor blockers (ARBs) may be protective against dementia, and studies in transgenic animals indicate that this may be due to improved amyloid-β (Aβ) clearance.

OBJECTIVE: We investigated whether taking ARBs was associated with an attenuation of age-related increases in cerebral Aβ retention, and reduced progression to dementia.

METHODS: Eight hundred seventy-one stroke-free and dementia-free older adults from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study underwent baseline lumbar puncture, and a subgroup (n = 124) underwent 12 and 24 month follow-up lumbar puncture. Participants were followed at variable intervals for clinical progression to dementia. Linear mixed models and ANCOVA compared ARBs users with those taking other antihypertensives (O-antiHTN) or no antihypertensives (No-antiHTN) on cerebrospinal fluid (CSF) Aβ and phosphorylated tau (P-tau) levels. Cox regression and chi-square analyses compared groups on progression to dementia.

RESULTS: ARBs users exhibited greater vascular risk and lower educational attainment than the No-antiHTN group. Longitudinal analyses indicated higher CSF Aβ and lower P-tau in ARBs users versus other groups. Cross-sectional analyses revealed age-related decreases in CSF Aβ in other groups but not ARBs users. ARBs users were less likely to progress to dementia and showed reduced rate of progression relative to the No-antiHTN group.

DISCUSSION: Patients taking ARBs showed an attenuation of age-related decreases in CSF Aβ, a finding that is consistent with studies done in transgenic animals. These findings may partly explain why ARBs users show reduced progression to dementia despite their lower educational attainment and greater vascular risk burden.

%B J Alzheimers Dis %V 50 %P 779-89 %8 2016 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/26757036?dopt=Abstract %R 10.3233/JAD-150487