P-685 Extracellular vesicles of human follicular fluid as biomarkers of ovarian disease

Abstract Study question Our aim is to analyze the morphology of follicular fluid extracellular vesicles (EVs) according to ovarian pathology by labeling the vesicles with luminescent gold nanoclusters. Summary answer Cryo-TEM analysis reveals that EVs from the follicular fluid of patients presenting with polycystic ovary syndrome have a particularly complex morphology compared to normo-ovulatory women. What is known already EVs are particles enclosed by a lipid membrane and secreted by cells. Previously considered as cellular debris, they are in fact involved in a multitude of biological functions and are potential biomarkers. Development of an optical biosensor based on luminescent nanoparticles would make it possible to analyze them in biological fluids. Study design, size, duration Samples were provided by GERMETHEQUE, Biobank dedicated to human fertility. Samples from 32 patients presenting with ovarian pathology (ovarian failure, polycystic ovary syndrome) and 32 normo-ovulatory patients were analyzed. Participants/materials, setting, methods Luminescent gold nanoclusters (1 to 2 nm in diameter) have been synthesized and functionalized in order to interact with extracellular vesicles. Analysis of the morphology of EVs was carried out by cryoTEM. Qualitative results were analyzed by Chi2 or Fisher tests. The quantitative results were analyzed by the Kruskal Wallis test. Main results and the role of chance The interactions between luminescent gold nanoclusters and lipid membranes show that it is possible to induce electrostatically and in a controlled manner either significant structural changes in the membranes or membrane labeling. Patients presenting with ovarian pathology have more oval vesicles (p = 0.0014). Differences are especially significant in polycystic ovary syndrome showing that simple vesicles are less abundant than controls (p < 0.0001) and large tubules more frequent (p = 0.0023). Limitations, reasons for caution The first results concerning the interactions between luminescent nanoclusters and vesicles demonstrate their potential for labeling these membrane structures Wider implications of the findings The characterization of these anomalies could allow a better understanding of ovarian pathology and open up new therapeutic fields. An efficient method of encapsulation in liposomes of gold nanoclusters has been developed. Trial registration number GERM 20220705