P-801 Human endometrial Organoids (hEOs): a non invasive powerful tool to study receptivity and a step forward precision medicine in IVF

Abstract Study question Organoids from menstrual blood (MB) can mimic human receptive endometrium? Summary answer This research provides a reliable and less invasive 3D endometrial model able to the window of implantation (WOI). What is known already Investigating physiology function normal cycling endometrium challenging due its great individual variability. hEOs are considered new step forward in precision medicine tool for study biology, associated diseases (i.e. endometriosis) understand complex mechanism surrounding endometrium-embryo cross talk. During WOI apical cytoplasmic protrusions traditionally called “pinopodes” reported be specific marker receptivity.Initially hypothesized form at sites blastocyst attachment, pinopodes have typically been correlated with successful strongly regulated by ovarian steroid hormones. design, size, duration usually obtained biopsy, here much source was employed. Menstrual retrieved cups processed isolate epithelial (Ep) stromal cells (hESC). hEOswere created investigate morphological changes occurring vivo during cycle, specifically WOI. For proof concept, we recruited five healthy volunteers January 2021 december 2022 signing an informed written consent this study. Participants/materials, setting, methods All participants provided use their MB samples. Female received instruction cups. exposed hormonal treatments milieu typical proliferative mid secretory phase cycle. Cultured were then observed Quanta 400 (FEI) scanning electron microscope (SEM). Main results role chance In succeeded establish 3Dmodel using both Ep hESC approach. The generated co-culture these two types used phase. expansion media has supplemented 10 − 8 M E2 + 6 P4 50 mM cAMP. Treated cultured 4 days; washed PBS fixed 2 h °C cold Karnovsky’s. Using Scanning Microscopy, closely luminal surface inner side characterized presence large 5-10 μm, plasma membrane uterine protrusions, not present unstimulated hEOs. Generally, days 17-19 cellular bulging increases formation small (1-2 μm) pinopodes. Their full development day 20and Limitations, reasons caution There discrepancies literature regarding pinopode morphology on course, may vary between individuals. Further studies, comprising individuals undergoing IVF should explored. Wider implications findings Effective embryo modeling necessary molecular event cascade that occurs vivo. Pinopodes responds stimuli, particular Progesterone, calibrate women IVF. Trial registration number Not applicable