Analysis of matrix metalloproteinase-7 expression in eutopic and ectopic endometrium samples from patients with different forms of endometriosis

The objective of the present study was to expand our understanding of the role of matrix metalloproteinase-7 (MMP-7) in the pathophysiology of endometriosis. Expression levels of MMP-7 mRNA and protein in the eutopic endometrium and ectopic endometrium of patients with different forms of endometriosis were measured with immunohistochemistry and real-time RT-PCR. Endometrial tissues from patients with uterine myomas and those with macroscopically normal pelvic cavities were included as comparison groups. The real-time RT-PCR utilized endometrial cells isolated by laser capture microdissection. MMP-7 immunostained cells were quantified using a computerized image analysis system. MMP-7 expression levels were significantly higher in the endometrial epithelial cells from patients with deep infiltrating endometriosis compared with those isolated from the endometria of patients with only superficial peritoneal endometriosis, uterine myomas or normal endometrium, in the proliferative, late secretory and menstrual phases. MMP-7 protein expression was detected in the ectopic endometrial epithelial cells of 13 samples of deep infiltrating endometriosis (24.5%), 11 samples of ovarian endometriosis (28.6%), 23 samples of black peritoneal lesions (76.7%) and 24 samples of red peritoneal lesions (100%). MMP-7 protein expression in epithelial cells was significantly higher in red peritoneal lesions compared with that of deep infiltrating endometriosis, ovarian endometriosis and black peritoneal lesions, in all phases of the menstrual cycle. These findings suggest that MMP-7 expression levels vary significantly among the different forms of endometriosis.