Expression of secretory leukocyte protease inhibitor in women with endometriosis

Objective: To explore endometriosis-related molecules in patients with use of differential display analysis. Design: Prospective study. Setting: Nagoya City University Medical School, Nagoya, Japan. Patient(s): Women with endometriosis (n = 27) and without endometriosis (n = 21). Intervention(s): Surgery was scheduled in the proliferative or secretory phase of the menstrual cycle. Main Outcome Measure(s): Differentially expressed products of endometrioma samples were sequenced at nucleotides. One of the candidate genes, secretory leukocyte protease inhibitor (SLPI) gene, was analyzed with use of in situ hybridization and Northern blot analyses. Distribution of SLPI was determined by immunohistochemistry, and the amount of SLPI in the peritoneal fluid and serum was measured by ELISA. Result(s): Distinct expression of SLPI messenger RNA could be detected in the endometrial-type epithelium of extrauterine endometriotic tissues and in the eutopic endometrium of women with endometriosis. SLPI was localized in the endometrial-type epithelium of endometriomas immunohistochemically. The amount of SLPI in the peritoneal fluid was markedly elevated in the endometriosis group (91.6 ± 6.6 ng/mL compared with 68.4 ± 5.3 ng/mL in the controls). Conclusion(s): Secretory leukocyte protease inhibitor may be involved in the pathogenesis of endometriosis.