Matrix metalloproteinase-9 activity in plasma of patients following surgical resection of endometrioma

Abstract

Objective: It is well established that endometriomas are detected with ultrasound and laparoscopy with pathologic confirmation. In some cases, however, the ultrasound finding may not be definitive. It has been established that MMPs are involved in the development of endometriosis. The present pilot study was performed to elucidate whether matrix metalloproteinase-9 (MMP-9) levels can be used to screen for recurrence of endometriomas. Design: Prospective observational study in patients treated with oral contraceptives to allow accurate measurement of levels in the midfollicular phase. Materials/Methods: Five patients with endometriomas were studied. Three patients had unilateral endometrioma and the two patients had bilateral endometriomas. All patients had definite confirmation of these findings on laparoscopy and pathology. We tested the preoperative plasma MMP-9 activity after 7 days of oral contraceptives (OCP) and again post-operatively after another 7 days of OCP. This method of testing avoided any inclusion of samples from the luteal phase or during menses. A control group of five patients who are tubal ligated and free of endometriosis were included. In the control group, we demonstrated that MMP-9 levels peaked during menses and minimum levels were seen in midluteal phase. The mid-follicular phase levels however were constant. Thus, treating patient with OCP avoided any false drop in the levels secondary to this cycle variation. Results: The mean active preoperative plasma MMP-9 levels were 57.00+/−8.98, whereas the mean postoperative plasma MMP-9 levels after resection were 33.93+/−3.84. Analysis of these findings with a two tailed t-test showed a statistical significance in the drop in MMP-9 activity following surgical resection of the endometrioma (p <.04). While this is a pilot study consisting of five patients, it supports the potential diagnostic role of MMP-9 in endometriosis. Conclusions: Preliminary data suggest that active MMP-9 levels may be used to confirm a clinical diagnosis of recurrence of endometriomas. Further studies including additional patients are underway. Considering MMP-9 levels vary in the menstrual cycle, if MMP-9 levels are to be used for diagnostic or prognostic purposes, the samples have to be matched in the menstrual cycle. In this study we controlled the normal variability by placing patients on oral contraceptives. Supported by: Department of Obstetrics, Gynecology and Women’s Health at University of Louisville.