P-802 Exploring the effects of phthalate mixtures on human endometrial organoids: Insights into transcriptomic and proteomic profiles throughout the menstrual cycle

Abstract Study question Does the exposure of human endometrial organoids (hEOs) to phthalates influence their transcriptomic and proteomic profiles, particularly during the window of implantation? Summary answer The mixture of phthalates altered the expression of several genes which are essential during the window of implantation. What is known already hEOs display a robust responsiveness to steroid hormones and accurately reproduce essential morphological features observed in the receptive endometrium in vivo. The conventional approach to evaluating chemical health risks has predominantly been centered on the assessment of individual substances, overlooking the reality that individuals are regularly exposed to diverse mixtures of phthalates, a class of Endocrine Disrupting Chemicals (EDCs). There is a limited number of studies indicating that phthalates and their combinations can have a negative impact on the endometrium. To this purpose, we explore the effect of this mixture on endometrial receptivity during the Window Of Implantation (WOI). Study design, size, duration Endometrial tissues (n = 6) used for this study were obtained, with written informed consent from all participants. The endometrial organoids were generated from the biopsies and treated with hormones to mimic the WOI. Samples were then exposed with a mixture of phthalates in order to study the transcriptomic and proteomic changes on these cells throughout the menstrual cycle, especially the WOI. Participants/materials, setting, methods hEOs were generated from endometrial biopsies of healthy volunteers (n = 6). Organoids were cultured for 4 days and then divided into: untreated without any hormonal treatment; stimulated with 10 nM estrogen (E2); treated with 10 nM estrogen, 1μM progesterone (P4) and 1μM cyclic adenosine monophosphate (cAMP). EOs were further on exposed to the phthalate mixture. Proteomic profiling was performed using 2-D electrophoresis and Mass spectrometry. Samples were also subject to transcriptomic analysis, by RNA sequencing. Main results and the role of chance hEOs present a suitable in vitro model for the screening of the impact of phthalate mixtures on the endometrium throughout the menstrual cycle. Cytotoxicity test confirmed that the chosen concentration (100x of the value referring to the geometrical means in urine) of the mixture is not toxic for the cells. The transcriptomic and proteomic analyses revealed several up-regulated or down-regulated genes which are involved into pivotal pathways implicated to the WOI. Limitations, reasons for caution This study represents a preliminary experiment. All results need to be validated on an enlarged number of samples to provide more statistical strength. Wider implications of the findings hEOs offer a robust in vitro model to simulate and gain a more profound comprehension of the consequences arising from the combinatory effects of EDCs, on the endometrium. This model proves valuable in examining the impact of various EDCs across different phases of the menstrual cycle. Trial registration number not applicable