Background and Aims:

The hormone fibroblast growth factor 21 (FGF21) is a regulator of metabolism mainly in the liver and adipose tissue. Circulating FGF21 levels are increased in type 2 diabetes mellitus and obesity. It is unclear if the placenta expresses FGF21 and if this expression is altered in GDM.  Furthermore, it is unclear if FGF21 is present in the fetal circulation. This study aims to assess placental expression of FGF21 in women with or without GDM and to analyze FGF21 expression in cord blood and its correlation with maternal serum levels of FGF21.

Materials and Methods:

Twenty women with GDM and 18 without were recruited and maternal blood, placenta and cord blood were collected.  Placental FGF21 mRNA expression was analyzed by qPCR using TBP as endogenous control and normalized for cellular composition.  Placental protein levels were quantified by western blot and serum FGF21 concentrations by ELISA.

Results:

The study groups were similar in maternal BMI, age, gestational age at delivery, and birthweight centile.  Women with GDM had increased FGF21 mRNA expression compared to controls (3.02 (0.58-36.15) vs. 0.32 (0.09-1.93); median (interquartile range), p=0.004).  FGF21 protein was detected in placenta, again with high interindividual variability, and was seven fold higher in GDM (2.89 (1.44-5.10) vs. 0.42 (0.05-1.98), p<0.05). Maternal serum FGF21 concentrations were similar in GDM (323 (75-921) pg/mL) and controls (269 (49-731) pg/mL, p=0.81). Maternal serum FGF21 levels did not correlate with placental FGF21 expression. No FGF21 was detected in cord serum.

Conclusion:

Placental expression of FGF21 mRNA and protein is increased in women with GDM. Placental FGF21 is not detectable in cord serum. There is no relationship between placental expression and maternal serum levels of FGF21.