Biomarkers for Insulin Resistance and Metabolic Syndrome

Background: There is increasing evidence that insulin resistance (IR) has an important implication in the pathogenesis of polycystic ovary syndrome (PCOS), a common endocrinopathy in women. This study was performed to investigate the impact of different treatments for IR on five currently discussed markers for insulin resistance: intact proinsulin, adiponectin, retinol-binding protein 4 (RBP4), resistin, and visfatin in patients with PCOS. Methods: Thirty-five women with clinically confirmed PCOS diagnosis were included in the study [age (mean±SD): 24.7±4.8 years; body mass index: 27.4±6.0 kg/m2]. They were randomized to receive either metformin (850 mg twice a day) or rosiglitazone (4 mg once a day). Blood samples for measurement of the HOMAIR score, visfatin, RBP4, intact proinsulin, resisitin, and adiponectin were taken at baseline and after 6 months of treatment. Results: Both drugs improved ovulation, and an increase in insulin sensitivity was observed, especially in the rosiglitazone arm. Adiponectin levels increased in both treatment arms (metformin: 8.6±3.3 to 16.7±7.2 mg/liter, p < 0.001; rosiglitazone: 8.2±3.5 to 26.2±9.5 mg/liter, p < 0.001), but the increase was more pronounced with rosiglitazon