Endocrine Abstracts

Irisin is a myokine induced by exercise, that converts white fat tissue to brown fat tissue, thereby increasing thermogenesis and providing energy expenditure. The aim of this study is to determine the relationships between serum irisin levels and glucose and lipid parameters in obese children with and without non-alcoholic fatty liver disease (NAFLD). A total of 60 pubertal obese children (31 F, 29 M, age range: 11–18 yrs.) were included in this study. 30 of Whom had NAFLD. The control group consisted of 28 healthy children (14 F, 14 M) who were similar in age and sex to the obese group.

Results: The median serum irisin level was lower in the obese group (5.26 μg/ml (4.2–6) μg/ml) than in the control group (7.5 μg/ml (6.5–9) (P<0.05). The median irisin levels in both patients with NAFLD (5.7 μg/ml (4.6–6.5) and without NAFLD (5 μg/ml (3.9–5.7) were lower than the control group’s (P<0.05). Serum irisin levels were not different between patients with and without NAFLD (P>0.05). According to the presence of insulin resistance in the obese group, irisin levels did not change (P>0.05). In the obese group, irisin were correlated with BMI, waist and arm circumfrence. In the whole study group, serum irisin levels correlated negatively with BMI, waist, hip and arm circumferences, waist/hip ratio, skinfold thickness (triceps and biceps) and AST, ALT levels. There were no correlations between serum irisin levels and LDL-C, triglyceride and total cholesterol, but a positive correlation was found with HDL-C. Consequently, low serum irisin levels are found in obese children. It is not different between patients with and without NAFLD. Irisin levels are correlated negatively with fat tissue parameters and ALT-AST levels. Low irisin levels may be related to the presence of decreased muscle mass and/or decreased brown adipose tissue and hepatic injury in obesity.