Expression pattern of osteopontin and αvβ3 integrin during the implantation window in infertile patients with early stages of endometriosis

To study endometrial receptivity in terms of osteopontin (OPN) and v3 integrin expression and co-expression in infertile women with early stages of endometriosis. We investigated the immunohistochemical expression and co-expression of OPN and v3 integrin in the endometrium of 20 infertile patients with Stage I or II endometriosis as the only detectable cause of infertility, 20 infertile patients with unexplained infertility and 20 fertile women undergoing tubal sterilization. Two endometrial biopsies were performed during a single menstrual cycle (postovulatory Day 7 to 8 and 4 days later) in each subject. No statistically significant differences regarding OPN and v3 integrin expression were found between infertile patients with endometriosis and the two control groups. There was no significant correlation between OPN and v3 integrin staining intensity in the mid-luteal phase biopsies in any of the groups studied. Endometrial OPN and v3 integrin expression or co-expression is not impaired during the window of implantation in patients with Stage III endometriosis. Further studies are needed to determine whether these results imply normal endometrial receptivity in such patients or add to the increasing uncertainty about the clinical value of assessing the endometrium with these markers of implantation.