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

Abstract

Objective: 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.

Design: An immunohistochemical study.

Setting: Tertiary care university medical center.

Patients: Sixteen patients undergoing a diagnostic laparoscopy as part of a subfertility work-up. All patients had regular and ovulatory cycles.

Interventions: 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.

Main outcome measures: The expression of cell adhesion molecules, including the integrin alpha 2 beta 1, alpha 3 beta 1, alpha 4 beta 1, alpha 5 beta 1, and alpha 6 beta 1 and E-cadherin, as determined by immunohistochemistry on frozen sections.

Results: All integrins tested could be detected in the endometrium samples and in endometriotic lesions. In menstrual effluent samples, positive staining for the integrins alpha 2 beta 1 and alpha 3 beta 1 was found in epithelial cells in 13 of 16 cases. Integrin alpha 5 beta 1 was detected in 11 of 16 samples, and integrins alpha 4 beta 1 and alpha 6 beta 1 were detected in 5 of 16 samples. In PF, integrin alpha 3 beta 1 was found in epithelial cells in 12 of 16 samples, integrin alpha 5 beta 1 in 5 of 16, and integrins alpha 4 beta 1 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.

Conclusion: Integrins alpha 2 beta 1, alpha 3 beta 1, alpha 4 beta 1, alpha 5 beta 1, 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.