Association of Cerebrospinal Fluid Adiponectin Levels With Cerebral Glucose Metabolism In Mild Cognitive Impairment: A Pilot Study

Abstract

Background: Adiponectin has been implicated in the pathophysiology of dementia, especially Alzheimer's disease. However, the association between cerebrospinal fluid (CSF) adiponectin levels and positron emission tomography (PET) imaging remains unclear.

Objective: To explore whether CSF adiponectin levels are associated with ¹¹C-Pittsburgh compound B (PiB) or ¹⁸F-fluorodeoxyglucose (FDG) uptake in amnestic mild cognitive impairment (MCI) subjects.

Methods: Thirty-four amnestic MCI subjects underwent PiB-PET, FDG-PET, and CSF analysis. The CSF adiponectin levels were measured using the Bio-Plex 200 suspension array system. PET uptake was assessed for the frontal and temporoparietal lobes and posterior cingulate gyrus, referenced against the cerebellar cortex. The increased brain amyloid burden was defined as a mean uptake value ratio greater than 1.4. Spearman's rank correlation analysis and a multiple regression model were used to examine the association between CSF adiponectin levels and PiB or FDG uptake.

Results: The mean age was 76.3 years; 38.2% were men, and 61.8% were women. A high amyloid burden was identified in 18 (52.9%) subjects. CSF adiponectin levels positively correlated with global FDG uptake (β = 0.45; 95% confidence interval (CI), 0.13 to 0.76, p < 0.01), especially in the parietotemporal lobe and posterior cingulate gyrus (β = 0.70; 95% CI, 0.41 to 0.99, p<0.01, β = 0.33; 95% CI, 0.03 to 0.63, p = 0.03, respectively) after adjusting for covariates, including age, sex, education years, body mass index, vascular risk factors, ApoEε4 status, and PiB status in all amnestic MCI subjects.

Conclusion: CSF adiponectin levels were associated with cortical glucose metabolism, particularly in the specific regions that connect with the medial temporal, but not brain amyloid burden in amnestic MCI subjects.

Keywords: 11C-Pittsburgh compound B positron emission tomography; 18Ffluorodeoxyglucose positron emission tomography; Adiponectin; cerebrospinal fluid; mild cognitive impairment; pilot study.