Endometrial vascular and glandular expression of integrin alpha(v)beta3 in women with and without endometriosis

The integrin alpha(v)beta3 functions in both cell-cell and cell-extracellular matrix adhesion, and has reported roles in platelet aggregation, immune function, tissue repair, tumour invasion, angiogenesis and uterine receptivity. The aim of this study was to use immunohistochemistry to describe the vascular and glandular expression of integrin alpha(v)beta3 in formalin fixed, paraffin embedded endometrium obtained from women with (n = 29) and without (n = 24) endometriosis. The results showed a significant increase in the percentage of vessels expressing alpha(v)beta3 in the endometrium of women with endometriosis compared with controls (P = 0.0001). This difference was more pronounced in the secretory phase (P = 0.001) than the proliferative phase (P = 0.016). There was no correlation between vascular alpha(v)beta3 expression and the endothelial cell proliferation index (P > 0.05). Vascular sprouts were not observed in any of the 53 endometrial tissues obtained from women with or without endometriosis throughout the menstrual cycle. Results from semi-quantitative scoring of gland immunostaining showed that neither controls (P = 0.3329) nor the endometriosis group (P = 0.2260) had any significant changes in terms of alpha(v)beta3 expression between the different stages of the menstrual cycle. There was also no difference in glandular alpha(v)beta3 expression between women with and without endometriosis (P = 0.4302). These results provide evidence for increased endometrial angiogenesis in women with endometriosis compared with controls, and suggest that glandular expression of alpha(v)beta3 is not related to uterine receptivity per se.