Matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-3 mRNA expression in ectopic and eutopic endometrium in women with endometriosis: a rationale for endometriotic invasiveness

Objective: To investigate mRNA expression of metalloproteinase-9 (MMP-9) an d tissue inhibitor of metalloproteinase-3 (TIMP-3) in ectopic endometriosis tissue and uterine endometrium from women with and without endometriosis t hroughout the menstrual cycle. Design: Molecular studies in human tissue. Setting: Department of Gynecology and Obstetrics, Reproductive Immunology L aboratory, Stanford University Medical Center. Patient(s): Fifty-three premenopausal woman (23 women with endometriosis an d 30 women without endometriosis undergoing laparoscopic surgery). Endometr ium and ectopic endometriosis tissue were obtained at the time of surgery. Intervention(s): None. Main Outcome Measure(s): mRNA expression from eutopic and ectopic endometri um was analyzed by quantitative, competitive PCR. Result(s): Both uterine endometrium and ectopic endometriotic tissue from w omen with endometriosis expressed significantly (P<.05) lower levels of TIM P-3 than endometrium from normal women. Also, ectopic endometrium expressed higher levels of MMP-9 and a higher ratio of MMP-B/TIMP-3 than eutopic end ometrium from normal and endometriosis patients. Conclusion(s): These results suggest that ectopic and eutopic endometrium f rom endometriosis patients may be more invasive and prone to peritoneal imp lantation because of greater MMP and less TIMP-3 mRNA expression than endom etrium from women without endometriosis. Thus, increased proteolytic activi ty may be one of the reasons for the invasive properties of the endometrium , resulting in the development of endometriosis. (C) 2001 by American Socie ty for Reproductive Medicine.