Gelatinase A (MM-2), gelatinase B (MMP-9) and their inhibitors (TIMP 1, TIMP-2) in serum of women with endometriosis: Significant correlation between MMP-2, MMP-9 and their inhibitors without difference in levels of matrix metalloproteinases and tissue inhibitors of metalloproteinases in relation to the severity of endometriosis.

Endometriosis is a highly prevalent gynecological condition, where the formation of endometriotic foci is linked with locally increased activity of matrix metalloproteinases (MMPs). In the present study, we tested the hypothesis that raised serum levels of MMPs might reflect the severity of endometriosis. We compared serum levels of MMP-2 and MMP-9, and of their tissue inhibitors TIMP-1 and TIMP-2, in infertile women, matched for age and body mass index, with either mild (stage I, END-I; n = 15) or severe endometriosis (stage IV, END-IV; n = 22). There was no difference in the concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 between the analyzed groups. There was, however, a correlation between MMP-9 and TIMP-1 for the combined group (n = 37) (r = 0.48; p = 0.0032) and in women with END-IV (r = 0.51; p = 0.0163), as well as a highly significant correlation between MMP-2 and TIMP-2 for the combined group (r = 0.69; p = 0.0001), END-I (r = 0.51; p = 0.0406) and END-IV groups (r = 0.77; p = 0.0001). There was also a significant correlation between TIMP-1 and TIMP-2 in the combined and END-IV groups (r = 0.39; p = 0.0182 and r = 0.5450; p = 0.0099, respectively). The balance between MMPs and their inhibitors is preserved in the serum of women with endometriosis, but serum concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 cannot be considered to represent a valid measure of the severity of endometriosis.