Circulating matrix metalloproteinases and their tissue inhibitors as markers for ethnic variation in pelvic floor tissue integrity

The purpose of the present study was to measure the plasma levels of matrix metalloproteinases (MMP)-2 and -9 and their tissue inhibitors (TIMP)-1 and -2, as surrogate biomarkers for pelvic floor tissue integrity in young, healthy multi-ethnic women. This was hoped to elucidate ethnic vulnerability to support-related pelvic floor dysfunctions. The plasma levels of MMP-2 and -9 and TIMP-1 and -2 were measured by sandwich ELISA in nulliparous, young (18-29 years) women volunteers (n=85) from five ethnic groups [n=17/group; Bahrainis, other Arabs, Filipinos, Indians/Pakistanis and Caucasians (Italians)] and compared with levels in Italians as the reference group. It was identified that the levels of plasma MMP-2 were significantly higher in Italians than in Bahrainis (P<0.001) and Filipinos (P<0.001), but significantly lower than in Indians/Pakistanis (P=0.013); whereas, the levels of plasma MMP-9 were significantly higher in Italians than in Bahrainis (P=0.009) and Indians/Pakistanis (P<0.015). The levels of plasma TIMP-2 were significantly lower in Italians than in Indians/Pakistanis (P=0.003), but the levels of plasma TIMP-1 were significantly higher in Italians than in all other groups (P<0.05) excluding Bahrainis. Although MMP-2 correlated negatively with TIMP-2 and MMP-9 correlated positively with TIMP-1, both correlations were not significant (r=0.071, P=0.533 and r=0.197, P=0.8, respectively). In all ethnic groups, MMP-9 level correlated positively with BMI (r=0.26, P=0.02), and TIMP-2 level with age (r=0.23, P=0.045). Overall, the trends for higher levels of MMP-2 and -9 and lower levels of TIMP-2 in the plasma of Caucasian women may indicate a greater tendency for collagenolysis and weaker connective tissue with increased risk of developing pelvic floor dysfunctions, and thus may potentially serve as biomarkers for pelvic floor tissue integrity.