Could the Relationship between Leptin and Soluble Leptin Receptor be a Predictive Link between Obesity and Type 2 Diabetes Mellitus?

Leptin and insulin are reported to maintain energy and glucose homeostasis. In this study the relationship between leptin, soluble leptin receptor (sOB-R) and insulin was evaluated in obese women (group 1) and obese diabetic women (group 2). Twenty four subjects as volunteers were studied. Twelve subjects were group 1, with mean age 48.4±1.02 years and BMI 37.4±0.58 Kg/m^2 and twelve subjects were group 2, with mean age 47.0±0.46 years and BMI 39.8±1.05 Kg/m^2. Anthropometric measurements were recorded, including height, weight and waist circumference. Body mass index (BMI) was calculated (weight in Kg/Height^2 in meter). Fasting blood samples were collected for glucose, cholesterol, triglycerides, leptin, sOB-R and insulin determination. Homeostatic model assessment (HOMA) was calculated to assess insulin sensitivity. The important results obtained showed that the mean levels of leptin, sOB-R and the calculated free leptin index (FLI) in group 1 were 38.6±1.39 ng/ml, 14.9±2.13 ng/ml and 3.0±0.34 respectively. Their values were 17.9± 3.06 ng/ml, 26.8±2.38 ng/ml and 0.8±0.13 in group 2. Insulin concentration and HOMA values were 11.8±0.95 mIu/ml, 2.9±0.09 and 12.0±0.70 mIu/ml, 5.05±0.71 in both groups respectively. Significant positive correlations were found between leptin and insulin concentration in group 1 and significant positive correlation of sOB-R with both glucose and insulin in group 2. We concluded that the elevated leptin, soluble leptin receptor axis, may augment glucose homeostasis and insulin sensitivity in obese women. These two biological parameters could be used to predict the development of diabetes mellitus in obesity syndrome.