title: Evaluation of cord blood irisin levels in term newborns with small gestational age and appropriate gestational age.
abstract: BACKGROUND
  Most recently, a novel myokine, named irisin, was identified in human that expressed by skeletal muscle after exercise. Irisin increases energy expenditure by turning white adipose tissue into brown adipose tissue. Thus improves carbohydrate homeostasis in humans. Irisin is considered as a potential biomarker for obesity and metabolic syndrome. In recent years, numerous studies have been conducted about irisin with adults, although number of studies with newborns is limited.
  
  
  OBJECTIVE
  To evaluate cord blood irisin level with small gestational age (SGA) and appropriate gestational age (AGA) in term newborns.
  
  
  METHODS
  A cross-sectional study of 34 AGA and 34 SGA term newborns who were born in (1-30) December 2015 in Fatih University Hospital. Estimated fetal weight were calculated using the Hadlock formula by gynecologists to pregnant women in second trimester. All the babies were classified at birth as SGA or AGA. SGA was defined according to the Lubchenco scale for gender and gestational age. We collected umbilical cord blood at the time of delivery. Cord blood irisin levels were measured using commercial enzyme-linked immunosorbent assays in our hospital laboratory.
  
  
  RESULTS
  Cord blood irisin levels were significantly lower in SGA group [median 30 (25 ± 8) ng/ml] than in AGA group [median 40 (39 ± 13) ng/ml, p < 0.001]. No statistically significant differences were observed among the groups in terms of the demographic features (gender, mode of delivery, gestational weeks, 1-5 min Apgar score) (p > 0.05). Mothers with gestational diabetes, hypertension, asthma, chronic disease, use of drug or a history of smoking exposure were excluded from the study. When the study data were evaluated, Yates Continuity Correction and Fisher's exact tests were used in descriptive statistical methods and for comparison of qualitative data.
  
  
  CONCLUSIONS
  Our results support the idea that irisin have a physiologic role in neonates. Low level of irisin is associated with the impaired carbohydrate metabolism in term infants with SGA. However, further studies with larger series are warranted to confirm this.
authors: Department of Pediatrics, Fatih University, Sahilyolu sk.no: 16 Dragos-Maltepe, 34844 Istanbul, Turkey.
authors: Esengul
authors: E
authors: Keleş
authors: Department of Biochemistry, Fatih University, Istanbul, Turkey.
authors: Filiz Fatime
authors: FF
authors: Turan
keywords: AGA; Cord blood irisin level; SGA; Term infant