Factors present in peritoneal fluid of endometriosis patients inhibit drug-induced apoptosis and induce migration of endometrial and endometriotic cells

Several studies have shown evidences of changes in peritoneal fluid composition in women with endometriosis. An altered function of peritoneal immune cells and higher levels of soluble substances such as cytokines, growth factors and prostaglandins are found in women with endometriosis compared to those without the disease. These variations in the composition of the peritoneal fluid are likely to play a crucial role in the formation and development of endometriosis. The aim of this study was to evaluate peritoneal fluid of patients with endometriosis with regard to its influence on survival and migration of endometrial and endometriotic cells. Therefore stromal and epithelial cells from endometrium and endometriotic lesions were isolated and cultured in vitro in the absence or presence of peritoneal fluid. In order to analyse the response to drug induced apoptosis the apoptosis-inducing agent staurosporine was added to the cells and apoptotic death was evaluated by measurement of caspase-3 and -7 activity. Cell death induced by staurosporine in endometrial and endometriotic cells was blocked by incubation with peritoneal fluid of endometriosis patients in a dose-dependent manner, showing that soluble factors present in the peritoneal fluid inhibit apoptosis induction. The effect of peritoneal fluid on migration of endometrial and endometriotic cells was also investigated. Experiments performed by wound healing assay and Boyden's chamber technique revealed that peritoneal fluid significantly increases migration of endometrial and endometriotic cells. The data of this study suggest that factors present in the peritoneal fluid of endometriosis patients may contribute to the abnormal survival and invasion of endometriotic lesions in the peritoneal cavity.