MON-220 Androstendione Affects Endometrial Gene Expression Profile During Window of Implantation in Obese Infertile Women with PCOS

Context: PCOS affects endometrium receptivity that leads to poor reproductive outcomes. Most investigated markers of endometrial abnormalities in this population are related to steroid hormones-induced alterations, derangements in glucose metabolism and inflammation. A distinctive impact of obesity and altered steroid profile on endometrial enviroment in PCOS needs further exploration. Objective: We hypothesized that obese infertile PCOS women with high androstendione level exhibits different endometrial gene expression than obese infertile PCOS women with normal androstendione level when compared to non PCOS controls.Patients and Methods: Endometrium was obtained during the window of implantation by timed biopsy from 15 obese infertile women with PHO phenotype of PCOS as classified by Rotterdam criteria by presence ofPCO morphology (P), clinical or biochemical hyperandrogenic features (H) and oligo-amenorrhoea (O) (age 31.1±4.4 years, body weight 105,4 ±9,8kg) and from 7 infertile normal weight controls without PCOS (group C). Seven women with PCOS had high androstendione level (12,7 ±2,6 nmol/l (group A)) and 8 had normal androstendione ( 7,5 ±1,7 nmol/l (group B)). Total testosterone was increased in 6 out of 7 women in the group A, whereas all women in the group B had normal total testosterone. By RNA sequencing of endometrium we identified 4317 significantly differentially expressed genes (DEGs) comparing group A to C and 5344 differentially expressed genes comparing group B to C. DEGs were retrieved for pathway analysis. Results: Comparing group A to C, we observed the top enriched pathways to be associated with activation of androgen-related genes, including androgen receptor and LEF1 gene. In addition, we observed the enriched pathway associated with GSK3β that has been previously related with increased PCOS susceptibility.When comparing group B to C, the analysis of upstream regulators showed activation of estradiol-dependent pathways and deactivation of progesterone-dependent pathways, whereas activation of androgen associated pathways was not observed. We also detected down-regulation in metabolic part of insulin signalling pathways associated with GLUT4 expression.Conclusions: Endometrial gene expression in obese infertile PCOS women with high androstendione level was associated predominantly with altered androgen related genes, whereas endometrium in a group with PCOS and normal androstendione exhibited mainly activation in estradiol and deactivation of progesterone dependent pathways. Further investigation of the endometrial markers is critical to develop tailored therapies targeting endometrium related reproductive disorders in different PCOS phenotypes.