Telomere length of granulosa cells is positively associated with oocyte maturation and fertilization.

Research question: Is it feasible to use the telomere length of granulosa cells as a biomarker for ovarian function and embryological outcomes during IVF?

Design: This prospective cohort study included 240 patients undergoing their first IVF cycle between October 2022 and December 2022. The main outcomes were the associations between relative telomere length of granulosa cells, collected during oocyte retrieval, and ovarian reserve, ovarian response and embryological outcomes.

Results: The mean ± SD relative telomere length was -5.35 ± 2.55. No significant relationships were found between telomere length and ovarian reserve and ovarian response. Telomere length was positively correlated with maturation rate (r = 0.386, P < 0.001) and fertilization rate (retrieved oocytes: r = 0.408, P < 0.001; matured oocytes: r = 0.203, P = 0.002). However, telomere length was not significantly correlated with oocyte retrieval or viable embryo rate. On multifactor linear regression, relative telomere length was associated with oocyte maturation rate (P < 0.001) and fertilization rate of matured oocytes (P = 0.011). The receiver operating characteristic curve of telomere length as a predictor of oocyte maturity showed that the area under the curve (AUC) was 0.719 (P < 0.001), while the AUC of telomere length as a predictor of fertilization (of matured oocytes) was 0.613 (P = 0.005).

Conclusion: Telomere length is correlated with embryological outcomes in IVF, mainly by affecting oocyte maturation and fertilization, rather than early embryo development. Telomere length alone cannot be used as a biomarker for ovarian reserve or ovarian response. When dealing with recurrent oocyte maturity or fertilization disorders, therapies oriented to lengthen telomeres or increase telomerase expression or function would facilitate cell division of granulosa cells, leading to higher oocyte maturation and fertilization rates.