Improvement of endothelial function with metformin and rosiglitazone treatment in women with polycystic ovary syndrome

Objective: There is evidence of preclinical cardiovascular disease even in young women with polycystic ovary syndrome (PCOS). The aim of our study was to assess and compare the effects of metformin (MET) and rosiglitazone (ROSI) on endothelial function in PCOS patients. Methods: For 6 months, 26 women with PCOS received either MET or ROSI. Blood samples for assessment of androgens, lipids and high-sensitive C-reactive protein were taken at baseline and at endpoint. Endothelium-dependent flow-mediated dilation (FMD) and glyceryl trinitrate-induced endothelium-independent dilation of brachial artery were studied before and after treatment. Homeostasis model assessment (HOMA(IR)) calculation was applied as a measure of insulin resistance (IR). Results: With treatment, FMD of brachial artery improved significantly from 4.2 +/- 6.6 to 10.2 +/- 5.9% in MET group (P = 0.036) and from 2.9 +/- 3.2 to 7.6 +/- 4.9% in ROSI group (P = 0.026). MET being as effective as ROSI (P = 0.70). The endothelium-independent dilation did not change. Additionally, administration of MET was associated with a significant decrease in HOMA(IR) (P = 0.003), serum total and serum-free testosterone (P = 0.045 and P = 0.008 respectively) and significantly higher frequencies of menstrual bleeding (P = 0.006). Conclusion: A 6-month therapy with insulin sensitizers. MET and ROST, resulted in marked improvement of endothelial function in young PCOS patients without clinically evident atherosclerosis who were not severely insulin resistant. Neither drug was superior to the other. We conclude that therapeutic intervention with either insulin sensitizer may reverse the atherosclerotic process in PCOS patients at its early stage.