Epigenetic age acceleration in follicular fluid and markers of ovarian response among women undergoing IVF

• Published in: Human reproduction (Oxford) 2024-09, Vol.39 (9), p.2003-2009
• Main Authors: Hood, Robert B, Everson, Todd M, Ford, Jennifer B, Hauser, Russ, Knight, Anna, Smith, Alicia K, Gaskins, Audrey J
• Format: Article
• Language: English
• Subjects: Adult; Biomarkers - metabolism; DNA Methylation; Epigenesis, Genetic; Estradiol - blood; Estradiol - metabolism; Female; Fertilization in Vitro - methods; Follicular Fluid - metabolism; Granulosa Cells - metabolism; Humans; Oocyte Retrieval; Oocytes - metabolism; Ovulation Induction
• ISSN: 0268-1161; 1460-2350; 1460-2350
• DOI: 10.1093/humrep/deae136

Abstract STUDY QUESTION Are markers of epigenetic age acceleration in follicular fluid associated with outcomes of ovarian stimulation? SUMMARY ANSWER Increased epigenetic age acceleration of follicular fluid using the Horvath clock, but not other epigenetic clocks (GrimAge and Granulosa Cell), was associated with lower peak estradiol levels and decreased number of total and mature oocytes. WHAT IS KNOWN ALREADY In granulosa cells, there are inconsistent findings between epigenetic age acceleration and ovarian response outcomes. STUDY DESIGN, SIZE, DURATION Our study included 61 women undergoing IVF at an academic fertility clinic in the New England area who were part of the Environment and Reproductive Health Study (2006–2016). PARTICIPANTS/MATERIALS, SETTING, METHODS Participants provided a follicular fluid sample during oocyte retrieval. DNA methylation of follicular fluid was assessed using a genome-wide methylation screening tool. Three established epigenetic clocks (Horvath, GrimAge, and Granulosa Cell) were used to predict DNA-methylation-based epigenetic age. To calculate the age acceleration, we regressed epigenetic age on chronological age and extracted the residuals. The association between epigenetic age acceleration and ovarian response outcomes (peak estradiol levels, follicle stimulation hormone, number of total, and mature oocytes) was assessed using linear and Poisson regression adjusted for chronological age, three surrogate variables (to account for cellular heterogeneity), race, smoking status, initial infertility diagnosis, and stimulation protocol. MAIN RESULTS AND ROLE OF CHANCE Compared to the median chronological age of our participants (34 years), the Horvath clock predicted, on an average, a younger epigenetic age (median: 24.2 years) while the GrimAge (median: 38.6 years) and Granulosa Cell (median: 39.0 years) clocks predicted, on an average, an older epigenetic age. Age acceleration based on the Horvath clock was associated with lower peak estradiol levels (−819.4 unit decrease in peak estradiol levels per standard deviation increase; 95% CI: −1265.7, −373.1) and fewer total (% change in total oocytes retrieved per standard deviation increase: −21.8%; 95% CI: −37.1%, −2.8%) and mature oocytes retrieved (% change in mature oocytes retrieved per standard deviation increase: −23.8%; 95% CI: −39.9%, −3.4%). The age acceleration based on the two other epigenetic clocks was not associated with markers of ovarian response. LIMITATION