Adipokine levels and carbohydrate metabolism in patients diagnosed de novo with polycystic ovary syndrome

Introduction: Central obesity appears to play a major role in the pathogenesis of metabolic disorders in polycystic ovary syndrome. Insulin resistance and carbohydrate disorders are associated with dysfunctional secretion of various adipokines by the adipose tissue. Objectives: This study aimed to evaluate leptin, apelin, and visfatin against a background of carbohydrate metabolism parameters in patients diagnosed de novo with polycystic ovary syndrome (PCOS). Material and methods: The study group consisted of 40 patients with PCOS (mean age, 29 years) diagnosed in accordance with the American Society for Reproductive Medicine criteria from 2003. The control group consisted of 37 clinically healthy women (mean age, 26 years). All controls had regular menses and no clinical or biochemical signs of hyperandrogenism. Concentrations of leptin, apelin, visfatin, and insulin were measured by immunoenzymatic methods. Glucose concentrations were determined using spectrophotometry. Results: Significantly higher concentrations of leptin, insulin, homeostatic model assessment for insulin resistance (HOMA-IR) index, and the immunoreactive insulin (IRI)/glucose index were found in the PCOS group than in the control group. Notably, the concentration of apelin was over five times lower in the PCOS group than in the control group. In patients with PCOS, a positive correlation was found between the concentrations of insulin and leptin and concentrations of leptin and IRI/glucose. Patients of the PCOS group with body mass index (BMI) ≥ 25 had significantly higher values of leptin, insulin, HOMA-IR index, and IRI/glucose index than patients of the PCOS group with normal BMI. In the PCOS group, a positive correlation was found between BMI and leptin concentration (r = 0.7176; p < 0.0001) and carbohydrate metabolism, such as insulin (r = 0.5524; p = 0.0003), glucose (r = 0.3843; p = 0.0157), HOMA-IR (r = 0.5895; p < 0.0001), and IRI/glucose (r = 0.3872; p = 0.0163). These findings were not observed in the control group. Conclusions: (1) Increased leptin concentration observed in women diagnosed de novo with PCOS as well as positive correlations between leptin and HOMA-IR, and IRI/glucose and BMI may indicate a potential role of leptin in the reduction of tissue sensitivity to insulin. (2) Significantly lower apelin concentration in the PCOS group (>5 fold) than in the control group, associated with a concomitant increase in leptin, may also contribute to carbohydrate metabolism disorders occurring in the course of PCOS.