Intrafollicular fibroblast growth factor 13 in polycystic ovary syndrome: relationship with androgen levels and oocyte developmental competence

BACKGROUND: Fibroblast growth factor 13 (FGF13) is one of the most highly expressed FGF family members in adult mouse ovary. However, its precise roles in ovarian function remain largely unknown. We sought to evaluate the associations between FGF13 in follicular fluid and oocyte developmental competence in patients with polycystic ovary syndrome (PCOS). METHODS: A cross-sectional study was conducted on 43 patients with PCOS and 32 non-PCOS patients who underwent in vitro fertilization/intracytoplasmic sperm injection treatments. The highest quartiles of follicular fluid (FF)-FGF13 (≥117.51 pg/mL) and FF-total testosterone (FF-TT) (≥51.90 nmol/L) were defined as “elevated” FF-FGF13 levels and “elevated” FF-TT levels, respectively. RESULTS: The levels of FF-FGF13 were skewed, with a median of 82.97 pg/mL (59.79–117.51 pg/mL) in 75 patients. The prevalence of elevated FF-TT levels was significantly higher in the PCOS patients with elevated FF-FGF13 levels than in those without (64.3% vs. 35.7%, adjusted P = 0.0096). FF-TT and increased ovarian volume (> 10 mL for one or both ovaries) were positively correlated with FF-FGF13 in PCOS patients (r = 0.37, P = 0.013; r = 0.33, P = 0.032). A negative association was evident between FF-FGF13 and the MII oocyte rate in the multiple linear regression analysis (β = − 0.10, SE = 0.045, adjusted P = 0.027). However, the associations were not evident in the non-PCOS patients. CONCLUSIONS: Our study suggests the presence of intrafollicular FGF13 in PCOS patients and implies that FGF13 might be involved in the pathophysiological process of PCOS. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13048-018-0455-3) contains supplementary material, which is available to authorized users.