Expression of integrins E-cadherin in cells from menstrual effluent, endometrium, peritoneal fluid, peritoneum, endometriosis

To detect the expression of integrins and E-cadherin in cells from peritoneal fluid (PF), endometrium, menstrual effluent, peritoneum, and endometriotic lesions during the early follicular phase of the menstrual cycle. An immunohistochemical study. Tertiary care university medical center. Sixteen patients undergoing a diagnostic laparoscopy as part of a subfertility work-up. All patients had regular and ovulatory cycles. A laparoscopy was performed in the early follicular phase (days 2 to 5). Simultaneously, samples were taken from endometrium, menstrual effluent, and PF, and a representative biopsy of an endometriotic lesion was obtained. If endometriosis was not noted, a peritoneal biopsy was obtained instead. The expression of cell adhesion molecules, including the integrin α2β1, α3β1, α4β1, α5β1, and α6β1 and E-cadherin, as determined by immunohistochemistry on frozen sections. All integrins tested could be detected in the endometrium samples and in endometriotic lesions. In menstrual effluent samples, positive staining for the integrins α2β1 and α3β1 was found in epithelial cells in 13 of 16 cases. Integrin α5β1 was detected in 11 of 16 samples, and integrins α4β1 and α6β1 were detected in 5 of 16 samples. In PF, integrin α3β1 was found in epithelial cells in 12 of 16 samples, integrin α5β1 in 5 of 16, and integrins α4β1 and α6β1 in 2 of 16. The antibody for E-cadherin showed positive staining of epithelial cells in 6 of 16 menstrual effluent samples. All endometrial tissue samples showed positive staining for E-cadherin. In PF, E-cadherin was detected in the epithelial cells of one sample. One peritoneum biopsy revealed positive staining for E-cadherin. Integrins α2β1, α3β1, α4β1, α5β1, and α6β1, and E-cadherin, important cell adhesion molecules, are expressed in endometriotic lesions and in cells and tissues that are potentially involved in the development of endometriosis. These cell adhesion molecules could be involved in the shedding of endometrial tissue during menstruation and the attachment of endometrial tissue fragments to the peritoneum.