Serum levels of irisin in gestational diabetes mellitus during pregnancy and after delivery.

Objective: Irisin has recently been introduced as a novel an exercise-inducible myokine which improves glucose metabolism in mice. However, regulation of circulating irisin in gestational diabetes mellitus (GDM) and in the peripartal period has not been assessed so far.

Methods: Circulating irisin was quantified in 74 GDM patients and in 74 healthy, pregnant, gestational age-matched controls. In a subset of these patients (44 GDM, 41 controls), postpartum follow-up data were also available. In a second study population of 40 healthy women with singleton pregnancies undergoing elective Cesarean section, irisin was assessed in maternal serum before and within 24h after delivery, as well as in umbilical cord blood and in placental tissue.

Results: In the first study population, median [interquartile range] irisin levels were significantly higher in GDM patients as compared to controls after delivery (previous GDM: 446.3 [146.9]μg/l; controls: 378.0 [111.4]μg/l) but not during pregnancy (GDM: 482.1 [132.1]μg/l; controls: 466.6 [178.0]μg/l). Interestingly, fasting insulin (FI) was independently and positively associated with serum irisin in multivariate analysis during pregnancy. In agreement with these findings, relative changes (ratio) of FI independently and positively predicted relative changes of irisin (ratio) in the second study population.

Conclusions: The myokine irisin is independently associated with FI in pregnancy. The physiological significance of these findings needs to be assessed in future experiments.