Increased epicardial fat and plasma leptin in type 1 diabetes independently of obesity

Visceral fat and related adipokines, such as leptin and adiponectin, have been recently suggested to play a role in type 1 diabetes. Nevertheless epicardial fat, the visceral fat of the heart, has been poorly explored in type 1 diabetes. In this study we sought to measure epicardial fat thickness, plasma leptin and adiponectin levels in type 1 diabetic subjects.

15 subjects with type 1 diabetes (age 52.8 ± 12, 10 females, 5 males, BMI 27.8 ± 5.2) and 15 non-diabetic controls underwent echocardiographic epicardial fat thickness measurement and blood tests for adipokines and Hemoglobin A1c (HbA1c). There were no differences in BMI, age, sex, blood pressure, inflammatory markers and adiponectin between subjects with diabetes and controls. Daily insulin requirement of subjects with type 1 diabetes was 0.54 ± 0.2 UI/kg and HbA1c was 7.6 ± 1.0 reflecting acceptable glycemic control. Patients with Type 1 diabetes showed significantly higher epicardial fat thickness (7.2 ± 2.1 vs 4.9 ± 2.5 mm p < 0.01) and plasma leptin levels (25.9 ± 19 vs 18 ± 12 ng/ml p < 0.01) than controls. Leptin resulted in the best independent correlate of epicardial fat thickness (R(2) = 0.48, p = 0.04, β = 2.45).

Our study provides two major findings of novelty: 1) subjects with type 1 diabetes have higher epicardial fat and serum leptin levels than non-diabetic subjects, 2) epicardial fat thickness and serum leptin levels are the best independent correlates of each other in patients with type 1 diabetes independently of BMI, HbA1c, daily insulin requirement. The mechanisms that link epicardial fat to leptin levels in type 1 diabetes remain to be elucidated.