The Sweet Side of IVF: Biological Role and Diagnostic Potential of Galectin-9 in Female Infertility

Infertility rates are indeed increasing globally, which emphasizes a pressing need to identify novel biomarkers exhibiting superior potential for laboratory diagnosis and personalized clinical management. This study aimed to explore the biological role of Galectin-9 (Gal-9) in female fertility and evaluate its diagnostic potential in the In Vitro Fertilization (IVF) program. A prospective cohort study was performed on 83 follicular fluids (FF) and 19 serum-FF pairs from IVF patients, 16 serum samples from fertile women, and 12 tissue sections. Gal-9 expression was characterized by immunostaining and ELISA. The ROC analysis was employed to evaluate the overall diagnostic performance. Cell-specific ovarian Gal-9 expression and significant differences in soluble Gal-9 levels were identified in the serum and FF of fertile and infertile women. Elevated intrafollicular Gal-9 levels were linked to poor ovarian reserve, served as a predictive marker for ovarian hyperstimulation, and marked unfavorable IVF outcomes. Follicular Gal-9 levels positively correlated with peak estradiol and total daily FSH dosage. ROC analysis revealed an excellent diagnostic value of Gal-9 for predicting fertilization success and a moderate ability to predict IVF outcomes. Our findings suggest a potential role for Gal-9 in oogenesis and its promise as a diagnostic marker for predicting fertilization success in IVF. However, further studies are needed to confirm its clinical utility in assisted reproduction.