Background: Obesity heightens the risk for both cardiometabolic complications and Alzheimer’s disease (AD). Although the reasons have yet to be fully elucidated, weight loss improves cognition. Given this link, factors overproduced by obese adipose tissue are ideal candidates for novel investigation into AD pathogenesis. We have recently shown that clusterin from the adipocyte is related to multiple factors of the metabolic syndrome (insulin resistance, dyslipidemia, NAFLD, and atherosclerosis). Clusterin is also involved in CNS lipid trafficking and has been proposed as an AD biomarker.

Rationale: Our goals were to characterize the effect of high-fat diet (HFD) feeding on CNS clusterin and neuronal insulin signaling in an AD mouse model (5XFAD); and furthermore, determine the relationship of adipocyte clusterin with neurocognition and insulin sensitivity in obese humans at baseline and following bariatric surgery.

Methods: We treated 5XFAD and WT mice with normal chow and HFD for 4 mo., measured CNS clusterin, and determined its effect on neuronal insulin signaling. We next measured subcutaneous adipocyte (SAd) clusterin expression, and performed neuropsychological evaluation and a hyperinsulinemic-euglycemic clamp procedure in obese human subjects (n=11) before and after sleeve gastrectomy.

Results: In the 5XFAD mice, HFD increases brain clusterin levels compared to WT, and in primary cortical neurons clusterin attenuates insulin signaling in a dose-dependent manner. In humans, SAd clusterin is related to hepatic insulin resistance, higher fasting glucose, and reduced working memory/attention. After sleeve gastrectomy SAd clusterin expression is reduced, with a significant inverse association between clusterin and working memory/attention and hepatic insulin sensitivity.

Conclusions: Our data suggests that SAd clusterin is a potential player in AD pathology, providing a critical link between excess adiposity, T2D, insulin resistance, and heightened AD risk.


D. Bradley: None. J.Z. Liu: None. A.M. Blaszczak: None. V.P. Wright: None. R. Tarawneh: None. Y. Liu: None. J. Ryu: None. S. Yoon: None. W. Hsueh: None.


American Diabetes Association (1-16-ICTS-049 to W.H.); National Institutes of Health (KL2TR001068, R01HL135622)

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