ESPE Abstracts

Background: In blood, leptin is suggested to circulate both in the free form as well as bound to soluble leptin receptor (sLR) and possibly also to other as yet unidentified binding protein. However, the role of the sLR in the regulation of the physiological function of leptin is until now unclear.

Objective and hypotheses: We aimed to investigate the relation of serum leptin and sLR levels with metabolic and anthropometric parameters in obese and healthy children.

Methods: The study included obese children with a BMI >95th percentile and healthy children with a BMI <85th percentile. The height, weight and waist circumference (WC) of the patients was measured for anthropometric evaluation. Fasting serum glucose, insulin, lipid profile, leptin, and sLR levels were measured to evaluate the laboratory parameters.

Results: The study included 35 obese and 36 healthy children. The obese children had significantly higher BMI, BMI–SDS, WC, triglyceride (TG), homeostasis model assessment of insulin resistance (IR), fasting glucose, and insulin levels compared to the healthy children (P<0.05). In the obese children serum leptin levels, free leptin index (FLI) and leptin/BMI ratio were found significantly higher, while sLR level was found significantly lower than the healthy children (P<0.05). Leptin level, FLI and leptin/BMI ratio were significantly higher among insulin-resistant obese children (P<0.05), while sLR level was similar between the groups when compared regarding the presence of IR (P>0.05). In the obese children, sLR level was negatively correlated with only total cholesterol and TG levels (P<0.05).

Conclusions: Findings of this study suggest that in obese children and adolescents decreased sLR level together with increased leptin level and FLI might be a compensatory mechanism for increasing leptin effect in peripheral tissue. Besides, in the obese group dyslipidemia and insulin resistance contributes toward the development of leptin resistance.