E- and P-selectin expression in endometriotic tissues and the corresponding endometria

Endometriosis is one of the most frequent diseases in gynecology. It is histologically defined as a non-malignant pathology in which endometrial-like tissue is found outside the uterus. The pathogenesis and mechanisms involved in the development of endometriosis-associated pain symptoms are still under investigation. A local peritoneal inflammation seems to play an important role in the origin of these symptoms. Selectins belong to a group of cell adhesion molecules that mediate the localization of circulating leukocytes on the endothelium at the sites of inflammation. The aim of this study was to investigate the expression of E- and P-selectins in endometriotic tissues and the corresponding endometria. Thirty endometriotic samples, 13 corresponding endometria and six endometria of patients without endometriosis were analyzed using an immunohistochemical technique. Just two endometriotic tissues expressed E-selectin, while five samples were positive for P-selectin. The selectin expression of the corresponding endometria was also very weak. No correlations between the revised American Fertility Society (rAFS) score or the hormonal situation of the patients at the time of biopsy and the selectin expression could be found. In conclusion, the selectin expression in endometriotic glands does not play an important role in the initiation of inflammatory processes caused by endometriosis. This inflammation must be considered as a secondary reaction after the implantation of the endometriotic glands, so that endometriotic tissues are not able to induce, by the expression of selectins, a direct inflammation.