Implication of the myokine irisin in maternal energy homeostasis in pregnancies with abnormal fetal growth

Abstract Objective: To prospectively investigate maternal concentrations of the myokine irisin in large for gestational age (LGA) and intrauterine growth restricted (IUGR) versus appropriate for gestational age (AGA) normal pregnancies and associate them with various perinatal parameters. Methods: Plasma irisin and insulin concentrations were measured by enzyme-linked immunosorbent assay (ELISA) and immunoradiometric assay (IRMA), respectively, in a cohort of 80 mothers delivering LGA (n = 30), IUGR (n = 30) and AGA (n = 20) singleton full-term infants. Results: Maternal irisin concentrations were similar among LGA, IUGR and AGA groups and did not correlate with respective insulin ones or maternal body mass index. In a combined group, maternal irisin concentrations decreased with advancing gestational age (p < 0.001) and were lower in multi-, compared to nulliparous women (p = 0.004). In the IUGR group, maternal irisin concentrations were higher in cases of smoking (p = 0.006). Conclusions: Irisin may not be differentially regulated in insulin resistance-associated pregnancy disorders resulting in fetal macrosomia and IUGR. Maternal irisin down-regulation with advancing gestation could possibly contribute to the observed maternal fat accumulation and progressive insulin resistance towards term. Similarly, lower maternal irisin concentrations in multiparous women may reflect the documented positive association between parity and fat deposition. Irisin up-regulation in cases of smoking may indicate the need for enhanced oxygen consumption to maintain energy production under conditions of hypoxia.