withdrawn by the author P-246 Endometrial alpha v beta 3 Integrin profile reflects endometrial receptivity defects in women with unexplained recurrent spontaneous abortions A. Germeyer, L. Nelson, A. Graham, J. Jauckus, T. Strowitzki, B. Lessey University Hospital Heidelberg, Gyn. Endocrinology and Reproductive Medicine, Heidelberg, Germany University of South Carolina, School of Medicine, Columbia, U.S.A. Clemson University, Clemens University, Clemson, U.S.A. University North Carolina, Dept. of Obstetrics and Gynecology, Chapel Hill, U.S.A. Introduction: Idiopathic recurrent spontaneous abortions (RSA), determined as two or more unexplained abortions are currently not well understood in their underlying pathophysiology. However several factors including low quality embryos, as well as cellular and molecular changes in endometrium may contribute to the inadequate fetal-maternal interaction resulting in pregnancy failure. As the expression of integrin anb3 a well known implantation marker is controversially discussed in the literature we herein aimed to determine the cellular expression of anb3 Integrin during the window of implantation in comparison with the endometrial morphology. Material and Methods: This retrospective case controlled study was performed on endometrial tissue obtained based on LH-timed endometrial pipell biopsies (EMB) of women with RSA (n = 21, age 33,6 ± 4,6) and healthy controls (n = 29; age 30,51 ± 3,9) after informed consent. EMB were taken during the luteal phase 8 to 10 days after a urinary LH surge, with aliquots formalin fixed and paraffin embedded for histological examination and a portion frozen in liquid nitrogen for immunohistochemistry for anb3 expression using the semi-quantitative HSCORE. Statistical analysis of mean HSCORE was performed by Mann Whitney unpaired test. Results: Endometrial avb3 integrin expression on the epithelial compartment normally occurs after day 19 (LH + 5) and persists until menstruation. In normal controls, positive integrin expression (HSCORE ≥ 0.7) was seen in 26 of 29 (89.6%) cases with a mean HSCORE of 1.93 ± 1.0. In RSA patients, positive staining was seen in only 6 of 21 cases (28.6%) with mean HSCORE of 0.82 ± 1.2 (p < 0.001). In controls, all three integrin negative samples were histologically delayed, while in integrin negative RSA patients 11/21 (52.4%) were “out of phase” (Type I defect), while 4/21 (19.0%) were histologically “in phase” (Type II defects). Within the “cases” with Type I defect (age33.3 ± 4,9) women had less abortions in their history compared to women with Type II defect (age34 ± 4.6) at the time of endometrial biopsies (3.1 ± 0.24 vs. 4.2 ± 0.46 SEM, p < 0.05). Furthermore, even though only a minority of RSA cases underwent laparoscopy, endometriosis was discovered in 5 cases. Overall D ow naded rom http/academ ic.p.com /um rep/article-ab6/suppl_1/i202/851820 by gest on 15 M arch 2020