Expression pattern of integrin adhesion molecules in endometriosis and human endometrium

Abstract

Integrins are cell adhesion molecules that undergo cell-specific dynamic changes during the normal menstrual cycle in the human endometrium. Here, using immunohistochemistry, we have investigated the expression pattern of the integrins α(v), α2β1, α3β1, α3, α6, β1, β2 and β3 in the human ectopic endometrium of 30 patients and in nine cases in the corresponding eutopic endometrium. The biopsies were obtained during the early or late follicular phase (25 cases), during the corpus luteum phase (four cases) and in one case after 6 months' treatment with a gonadotrophin releasing hormone (GnRH) agonist. The integrin expression was independent of the ovarian steroid situation at the time of biopsy. The integrin α6 was expressed in all endometriotic and endometrium samples. The integrin α3 was absent in all endometrium tissues of patients with endometriosis. However, the corresponding endometriotic lesions re-expressed this adhesion molecule in 15 cases. No change in integrin β3 expression pattern could be demonstrated in either endometriotic lesions or endometrium samples, regardless of the menstrual cycle phase. A correlation between serum oestradiol and progesterone concentrations and the expression of the investigated integrins was not observed, thus indicating that these two hormones play a minor role in the regulation of the cell adhesion molecules examined. Our investigation suggests that endometriosis is a dedifferentiated disease as it expressed different integrins in comparison with the eutopic endometrium, and independently of the hormonal situation. The ability of endometriotic tissues to express integrins may explain the high recurrence rates in patients with endometriosis, as these samples retain their adhesion potency after retrograde menstruation and are thus able to establish cell-cell and cell-matrix interactions with the surrounding peritoneum.