Matrix metalloproteinases 2 and 9 and MMP9/NGAL complex activity in women with PCOS

It is believed that matrix metalloproteinases (MMPs) play important roles in follicular development and pathogenesis of polycystic ovary syndrome (PCOS). However, conflicting results are available about the alteration of MMP2 and MMP9 concentrations or activities in PCOS. In fact, there is no study entirely investigating both concentration and activity of these MMPs and serum levels of their tissue inhibitors TIMP2 and TIMP1, as well as lipocalin-bound form of MMP9 (MMP9/NGAL). Therefore, the thoroughness of previous studies is questionable. This study was conducted to determine circulatory concentration of MMP2, MMP9, MMP9/NGAL complex, TIMP1 and TIMP2 as well as gelatinase activities of MMP2, MMP9 and MMP9/NGAL complex in women with PCOS and controls. Mean age and BMI as well as serum levels of total cholesterol, triacylglycerol, HDL-C, LDL-C, fasting blood sugar (FBS), insulin, estradiol and sex hormone-binding globulin did not differ between groups, whereas a marked decrease in FSH and significant increases in LH, LH/FSH ratio, testosterone and free androgen index were observed. Women with PCOS and controls showed closed concentrations of MMP2, MMP9, MMP9/NGAL, TIMP1 and TIMP2. Gelatinase activity of MMP9 was found significantly higher in PCOS than in controls (64.53±15.32 vs 44.61±18.95 respectively) while patients and healthy subjects showed similar activities of MMP2 and MMP9/NGAL complex. Additionally, PCOS patients showed a higher MMP9/TIMP1 ratio compared with control women. Direct correlations were also observed between circulatory MMP9 level and the concentration and activity of MMP9/NGAL complex. In conclusion, based on the results of present study, we believe that MMP9 may be involved in the pathogenesis of PCOS.