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Publication Date

2015-07-19

Availability

UM campus only

Embargo Period

2016-07-18

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Psychology (Arts and Sciences)

Date of Defense

2014-06-11

First Committee Member

Phil McCabe

Second Committee Member

Bonnie Levin

Third Committee Member

Maria Llabre

Fourth Committee Member

Armando Mendez

Fifth Committee Member

Neil Schneiderman

Sixth Committee Member

Clinton Wright

Abstract

Objective: BMI in midlife has been shown to increase the risk of dementia later in life, independent of other cardiovascular comorbidities. However, this association reverses direction later in life (age 60-70 years) such that older individuals with dementia have lower BMIs than those without dementia. Adiponectin, an anti-inflammatory cytokine released by adipose tissue, is negatively correlated with body weight and BMI. Adiponectin exists in low molecular weight (LMW) and high molecular weight (HMW) isoforms. It has been proposed that LMW adiponectin may have central effects. This study examined the association of circulating adiponectin isoforms with BMI, memory performance, and brain morphology (hippocampus and white mater hypointensities), in older individuals with memory complaints. Participants and Methods: Ninety-two participants (Mage=75, SD=9) from the University of Miami Memory Disorders Clinic consented to donation of a blood sample and were included for analyses in the present study. Adiponectin immunoassays for adiponectin isoforms were developed with monoclonal antibodies. Memory was measured with the Logical Memory test from the Uniform Data Set (UDS) of the National Alzheimer’s Coordinating Center. Scores were adjusted for demographic factors. Results: Linear regression analyses revealed that BMI predicted total adiponectin (b=-.06, p<.05) and LMW adiponectin (b=-.03, p<.05). Elevated levels total and LMW adiponectin significantly predicted poor immediate memory performance, but only for women (p<.05). We found no significant association with delayed verbal memory. There were also no significant associations among adiponectin isoforms, hippocampal volume, and white matter hypodensities. Conclusions: This study provides preliminary evidence that LMW may exert central effects and serve as an important biomarker of the aging process and cognition. This investigation also highlights an important gender difference in biomarkers of neurodegenerative disease. Further research in larger samples is needed.

Keywords

adipose tissue; adiponectin; HMW; LMW; cognition

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