P-350 Oocyte quality and infertility due to endometriosis: crucial role of extracellular vesicles (EVs) and their microRNAs content

Abstract Study question Could EVs and their miRNAs content of serum and follicular fluid have a role in impairment of oocyte quality in infertile women with endometriosis? Summary answer EVs and cargo of miRNAs isolated from follicular fluid have a pivotal role related to oocyte quality in infertility associated with advanced endometriosis. What is known already Endometriosis is a highly prevalent disease among women of reproductive age, strongly, associated with infertility. EVs and they cargo of microRNAs (miRNAs) are involved as mediators of cellular communication transferring several molecules to the maturing oocyte during all stages of oocyte development. Therefore, EVs could be involved as a possible mechanism involved in impairment of the oocyte quality questioned in disease-related infertility. However, to date, no study has evaluated EVs in the serum and follicular fluid of infertile women with endometriosis focusing on impaired oocyte quality. Study design, size, duration This observational case-control study consisted of 30 infertile women divided in moderate and severe endometriosis without endometrioma (n = 10) and male factor infertility (n = 20). Serum and follicular fluid were collected between November 2018 and December 2022 at the time of oocyte capture for ICSI. Participants/materials, setting, methods EVs were isolated by ultracentrifugation protocol and characterized for size and quantification by Nanoparticle tracking analysis (NTA). The expression of selected miRNAs was evaluated by RT-PCR. Enrichment analysis of the pathways predicted by the miRNAs identified were identified by DIANA-miRPath in agreement with database Kyoto Encyclopedia of Genes and Genomes (KEEG). Main results and the role of chance The present work found an increase of EVs-size from follicular fluid in infertility associated with advanced endometriosis without endometrioma group. Moreover, the comparison between follicular fluid and serum inside the infertility associated with advanced endometriosis without endometrioma group revealed an increase in EVs-size and EVs-quantification in the follicular fluid. MiRNAs expression by RT-PCR analysis highlighted 73 of 82 specific miRNAs related with oocyte quality. A total of 25 miRNAs were differentially expressed between the groups. Of these, fold change greater than 1.5 revealed that 24 miRNAs (miR-127-3p, miR-139-5p, miR-141-3p, miR-145-5p, miR-151-3p, miR-185-5p, miR-187-3p, miR-191-5p, miR-206, miR-21-5p, miR-214-3p, miR-24-3p, miR-30c-5p, miR-31-5p, miR-330-3p, miR-378-3p, miR-423-3p, miR-425-3p, miR-490-3p, miR-504-3p, miR-574-5p, miR-885-5p, miR-877-5p e miR-92a-3p) overexpressed in advanced endometriosis without endometrioma group. One miRNA was exclusive in infertile control and thirteen were exclusive in advanced endometriosis groups. These miRNAs were involved in focal adhesion and regulation of the reorganization of the actin cytoskeleton, as well as in signaling pathways, including ErbB, Ras, MAPK, Hippo, Rap1, cAMP and WNT. The results pointed to the relationship between miRNAs and follicular development and the acquisition of oocyte competence, whose dysregulated modulation could favor the worsening of gametic quality. Limitations, reasons for caution This study represents a preliminary experiment. Although the results from the miRNA expression profile are indicative of biological relevance, further comparative studies in larger study cohorts and implicated pathways are required. Wider implications of the findings This pilot study, opens new perspectives for advancement in the use of EVs and they cargo of miRNAs in advanced endometriosis without endometrioma group, supporting the importance of EVs in oocyte quality of infertile women associated with advanced endometriosis. They are the initial step to maximizing fertility potential in ART. Trial registration number No