Circulating SIRT1 inversely correlates with epicardial fat thickness in patients with obesity

Background and aim: Obesity is increasing worldwide and is related to undesirable cardiovascular outcomes. Epicardial fat (EF), the heart visceral fat depot, increases with obesity and correlates with cardiovascular risk. SIRT1, an enzyme regulating metabolic circuits linked with obesity, has a cardioprotective effect and is a predictor of cardiovascular events. We aimed to assess the relationship of EF thickness (EFT) with circulating SIRT1 in patients with obesity. Methods and results: Sixty-two patients affected by obesity and 23 lean controls were studied. Plasma SIRT1 concentration was determined by enzyme-linked immunosorbent assay (ELISA). EFT was measured by echocardiography. Body mass index (BMI), waist circumference, heart rate (HR), blood pressure, and laboratory findings (fasting glucose, insulin, HbA1c, cholesterol, and triglycerides) were assessed. SIRT1 was significantly lower (P = 0.002) and EFT was higher (P < 0.0001) in patients with obesity compared with lean controls. SIRT1 showed a negative correlation with EFT and HR in the obesity group (rho = -0.350, P = 0.005; rho = -0.303, P = 0.008, respectively). After adjustment for obesity-correlated variables, multiple linear regression analysis showed that EFT remained the best correlate of SIRT1 (beta = -0.352, P = 0.016). Conclusions: Circulating SIRT1 correlates with the visceral fat content of the heart. Serum SIRT1 levels might provide additional information for risk assessment of coronary artery disease in patients with obesity. (C) 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.