L26/P-348 Increased expression of key mTOR/AKT signaling pathway genes in granulosa cells of young women with endometriosis

Abstract Study question Are there differences at the molecular level in the most important genes of the mTOR/Akt-pathway in granulosa cells (GCs) of patients with or without endometriosis? Summary answer Our data show increased gene expression of AKT1, FOXO3 and S6K, particularly in endometriosis patients ≤35 years, suggesting increased activation of the mTOR/Akt-signaling-pathway. What is known already An accelerated decline in AMH levels has been demonstrated in patients with endometriosis. Similarly, a recent study shows a 1.4-fold increased risk of naturally premature ovarian insufficiency (POI) in endometriosis patients. Excessive activation leads to premature depletion of primordial follicles and thus to a reduced ovarian reserve. Consistent with this, histological studies have shown that in patients with endometriomas, the proportion of primordial follicles mediated by the PI3K-PTEN-Akt-Foxo3-signaling-pathway is low, while the proportion of growing follicles is high. GCs are crucial for follicle maturation. The PI3K/AKT/mTor-signaling-pathway in GC plays a central role in the activation of primordial follicles. Study design, size, duration This prospective study included 202 women with (n = 66) and without endometriosis (n = 136) who underwent follicular sampling at the University Women’s Hospital in Heidelberg, Germany, between 2013 and 2023. Quantitative expression analyses of the genes AKT1, FOXO3, FOXO1, mTOR, S6K, TSC2 in granulosa cells were performed using specific TaqMan® assays. Clinical and demographic information was obtained from medical records and questionnaires. Participants/materials, setting, methods For this analysis, GCs were isolated from follicular fluid obtained during follicular sampling as part of IVF treatment. After RNA isolation with TRIzol® and cDNA synthesis by reverse transcription, gene expression analysis was performed with TaqMan® for AKT1, FOXO3, FOXO1, mTOR, S6K, TSC2, and two housekeeping genes, HPRT and TBP. Relative gene expression was analyzed using the ΔΔCt method. Statistical analysis was performed using SPSS. Statistical significance was set at p < 0.05. Main results and the role of chance We observed a significant increase in the expression of AKT1, FOXO3 and S6K in the GCs of endometriosis patients. In the subgroup analysis, the increased expression of AKT1, FOXO3 and S6K was particularly evident in patients ≤ 35 years, whilst no significant change was observed in patients >35 years. Significant changes in AKT1, FOXO3 and S6K were observed especially in patients without ovarian involvement of the present endometriosis localisation, regardless of the stage. We found no difference in embryo quality between patients with or without endometriosis, regardless of ovarian involvement, but we did find a difference in pregnancy rates: At 42.9% in the endometriosis group ≤ 35 years, the rate is in line with previously reported pregnancy rates in endometriosis but significantly lower than the 68.3% in the control group. No significant difference was found in patients > 35 years of age. Our data suggest that the activation of the mTOR/Akt-signaling-pathway is more likely to be a sign of a systemic effect of endometriosis rather than a local reaction due to ovarian involvement. It is particularly evident in young patients, as age-dependent activation of this pathway more frequently occurs in patients > 35 years. Limitations, reasons for caution Our findings are based on RNA studies. Larger analyses involving a greater number of endometriosis patients in particular, including an examination of protein levels, would be desirable to strengthen our findings. Wider implications of the findings The upregulation of key genes in the PI3K/AKT/mTor-signaling-pathway in GC, particularly in young women, could be a sign of the consequent increased activation of primordial follicles and represent a mechanism for the more rapid decline in ovarian reserve and the increased likelihood of POI. Trial registration number No