Elevated expression levels of matrix metalloproteinase-9 in placental villi and tissue inhibitor of metalloproteinase-2 in decidua are associated with prolonged bleeding after mifepristone-misoprostol medical abortion

Abstract

To determine whether the expression levels of matrix metalloproteinases 2 and 9 (MMP-2 and -9) and tissue inhibitors of metalloproteinases 1 and 2 (TIMP-1 and -2) in the villi and the decidua are associated with prolonged bleeding after medical abortion. Case-controlled study. University hospital. Mifepristone-misoprostol medical abortion patients were divided into two groups (20 women each) based on the length of time (>14 or ≤14 days) of bleeding after the abortion. Discharged villi and deciduas were collected. The expression levels of MMP-2 and -9 and TIMP-1 and -2 in the villi and deciduas were assessed with semiquantitative immunohistochemistry. The median semiquantitative immunohistochemistry staining index (SI) scores for MMP-9 expression in the villi were elevated in the bleeding group compared with the control group (median SI scores 0.31 and 0.03, respectively). TIMP-2 expression was elevated in the decidua in the bleeding group compared with the control group (median SI scores 1.00 and 0.20, respectively). No significant differences were observed between the two groups in the expression levels of MMP-2 in the villi or of MMP-2, MMP-9, or TIMP-1 or of the ratios of MMP-9/TIMP-1 or MMP-2/TIMP-2 in the decidua. Elevated expression levels of MMP-9 in the villi and of TIMP-2 in the decidua were associated with prolonged bleeding after medical abortion.