Alterations in expression of endometrial endothelial nitric oxide synthase and αvβ3 integrin in women with endometriosis

Objective: To determine the expression of endometrial endothelial nitric oxide synthase (eNOS) protein and alpha(v)beta(3) integrin in patients with and without endometriosis. Design: Case-control cohort study. Setting: University-based tertiary care center. Patient(s): Endometrial biopsy samples were obtained from 9 fertile women with regular cycles and 30 infertile women with varying severity of endometriosis. Peritoneal fluid levels of nitric oxide were determined in 13 infertile women with a normal pelvis and 12 infertile women with endometriosis. Main Outcome Measure(s): Expression of eNOS and alpha(v)beta(3) integrin protein in the endometrium and peritoneal fluid levels of nitric oxide. Results: In patients with endometriosis, expression of eNOS was significantly increased in the glandular and luminal epithelium, with no significant changes in the stroma. Peritoneal fluid levels of nitric oxide were unchanged, and expression of alpha(v)beta(3) integrin expression in glandular and luminal epithelium was significantly decreased compared with controls. A significant negative correlation was observed between luminal expression of eNOS and alpha(v)beta(3) integrin and between glandular expression of eNOS and luminal expression of alpha(v)beta(3) integrin. Conclusion(s): The nitric oxide pathway may play a role in the pathogenesis of endometriosis.