Matrix metalloproteinase-2 and -9 expression correlated with angiogenesis in human adenomyosis

Adenomyosis is an important cause of dysmenorrhea and infertility for women all over the world, however, the pathogenesis has not been completely elucidated. The purpose of the study was to investigate the role of matrix metalloproteinases (MMPs) and their relation to angiogenesis in human adenomyosis.

Adenomyotic endometrial specimens were removed by hysterectomy from 68 women with adenomyosis. The control group consisted of 26 normal endometrial specimens. Immunohistochemistry was used to demonstrate expression of MMP-2, -9, vascular endothelial growth factor (VEGF) and microvessel density (MVD). Staining intensity was analyzed by computerized image analysis system.

In both eutopic and ectopic endometrium of adenomyosis, the expression of MMP-2, -9 as well as VEGF was significantly greater than in normal endometrium (p < 0.05). MVD was higher in ectopic endometrium than eutopic endometrium with or without adenomyosis (p < 0.05). In adenomyosis, a positive correlation was observed between VEGF expression and MMP-2 (p < 0.001, r = 0.583) as well as MMP-9 expression (p = 0.002,r = 0.490). A positive correlation was also found between MVD and MMP-2 (p < 0.001,r = 0.589) or MMP-9 expression (p < 0.001,r = 0.589).

Our results indicate that the elevation of MMP-2, -9 expression may have an important role in the development of adenomyosis, probably through contributing to invasion of endometrial tissues into the myometrium and angiogenesis in adenomyotic implants.