Poster Session 1 - R7
1,2Tina Tu-Thu Ngoc Nguyen, 1Stewart J. Russell, 1,2,3,4,5Clifford Librach
1 CReATe Fertility Centre, Toronto, ON, Canada; 2 Dept. of Physiology, University of Toronto, ON, Canada; 3 Dept. of Obstetrics and Gynaecology, University of Toronto, ON, Canada; 4 Institute of Medical Science, University of Toronto, ON, Canada; 5 Dept. of Gynaecology, Women’s College Hospital, Ontario, Canada
Conception is a complex process that requires synchronized cross-communication between a developed embryo and receptive endometrium. Implantation failure remains one of the largest challenges for assisted reproductive technologies (ART). Comparative studies analyzing the endometrium in fertile and infertile women reported that poor reproductive success is in part due to failure of the endometrium to achieve a receptive state; inadequate endometrial receptivity is responsible for two-thirds of implantation failures. A thin endometrium is often the reason for embryo transfer postponement since adequate thickness (>7 mm) is an indicator of receptivity. Although, many women have unexplained recurrent implantation failure (RIF) despite their endometrial thickness being >7 mm. It is important to evaluate the receptive status of the endometrium and develop treatments to increase receptivity and allow for synchronized embryo transfer. We aim to determine and compare endometrial receptive status of women with RIF or a thin endometrium with women with previous pregnancy success. We hypothesize that the endometrium of women with RIF or a thin endometrium will be in an unreceptive state and display altered/abnormal expression of receptivity biomarkers compared to that of fertile women. Informed consent will be obtained from women 18-45 years of age with previous pregnancy success (control group) and with RIF or a thin endometrium at the CReATe Fertility Centre (REB #34490, University of Toronto). Fluid will be removed following a sonohysterogram and/or a biopsy sample will be acquired from excess tissue after an endometrial tissue sampling procedure. Samples will be will be further categorized as pre-receptive, receptive, and post-receptive depending on when these procedures are performed during their menstrual cycle. Following enzymatic isolation, endometrial stromal cells (eSCs) will be cultured on collagen I whereas epithelial cells (eECs) will be cultured on Matrigel, up to 5 passages. Cell phenotype will be characterized at all passages by performing immunocytochemistry (ICC) for stromal (vimentin and TE-7) and epithelial (cytokeratin, and epithelial-specific antigen (EpCAM)) markers. The receptive status of the endometrial cells will be determined by performing ICC for receptivity biomarkers (ανβ3 integrin, CD98, progesterone receptor (PR), leukemia inhibitory factor (LIF), LIF receptor (LIFR), glycoprotein (gp) 130, and mucin (MUC)-1). Pre-receptive control samples are expected to show high levels of epithelial PR expression that will diminish towards the receptive phase. Whereas ανβ3 integrin, CD98, LIF, LIFR, gp130, and MUC-1 will show maximal expression for samples collected during the receptive phase. eECs and eSCs isolated from patients with RIF or a thin endometrium are predicted to show altered PR expression and lower expression of ανβ3 integrin, CD98, LIF, LIFR, gp130 and MUC-1. To our knowledge, there has not been an in vitro comparison of endometrial receptivity between fertile and patients with RIF or a thin endometrium, as well as investigating the efficacy of novel therapies to increase endometrial receptivity and implantation success. Once the receptive state of endometrial samples collected from our control, RIF, and thin endometrium groups have been determined, we will use our in vitro cultures to test the efficacy of potential therapies to increase endometrial cell proliferation and receptive status. This project was funded by the CReATe Fertility Centre.