Improvement in endothelial structure and function after metformin treatment in young normal-weight women with polycystic ovary syndrome: Results of a 6-month study

Context: Recent data indicate that women affected by the polycystic ovary syndrome ( PCOS) are at greater risk for cardiovascular disease and that metformin may improve the metabolic alterations in these patients. Objective: The objective of this study was to evaluate the effects of 6 months of metformin administration on endothelial structure and function in women with PCOS. Design: This was a prospective, baseline- controlled, clinical study. Setting: The study was performed at University Federico II ( Naples, Italy). Patients: Thirty young normal- weight women with PCOS without additional metabolic or cardiovascular diseases were studied. Interventions: Metformin ( 850 mg daily) was administered for 6 months. Mean Outcome Measures: The main outcome measures were complete hormonal profile, including total testosterone, SHBG, dehydroepiandrosterone sulfate, prolactin, and gonadotropin levels; serum insulin and glucose levels during a 75- g 2- h oral glucose tolerance test; plasma endothelin- 1 concentrations ( picomoles per liter +/- SD); serum lipid profile; brachial artery baseline diameter ( millimeters +/- SD), diameter after reactive hyperemia ( millimeters +/- SD), and flow-mediated dilation ( percentage +/- SD); and the intima media thickness ( millimeters +/- SD) on both common carotid arteries. Results: After treatment, SHBG levels and the free androgen index changed significantly ( P < 0.001). High- density lipoproteins and the area under curve for glucose/ area under curve for insulin ratio also significantly ( P < 0.001) increased, whereas low- density lipoproteins and plasma endothelin- 1 levels were significantly ( P < 0.001) reduced. No other change was found in any of the biochemical parameters evaluated. A significant difference was observed in brachial artery baseline diameter ( 3.24 +/- 0.30 vs. 3.0 +/- 0.30), flow- mediated dilation ( 14.30 +/- 1.90 vs. 15.70 +/- 1.50) ( P < 0.01, each), diameter after reactive hyperemia ( 3.70 +/- 0.30 vs. 3.55 +/- 0.10) ( P < 0.05), and intima media thickness ( 0.53 +/- 0.09 vs. 0.40 +/- 0.07) ( P < 0.001) after metformin treatment in comparison with baseline values. Conclusions: A 6- month course of metformin improves endothelial structure and function in young, normal- weight women with PCOS.