title: Cord blood irisin levels are positively correlated with birth weight in newborn infants.
abstract: BACKGROUND
  Irisin is a novel myokine, secreted from skeletal muscle after exercise. Irisin mediates exercise-related energy expenditure by turning white adipose tissue (WAT) into brown adipose tissue (BAT). Thus, irisin is considered as a potential biomarker for obesity and metabolic syndrome. Infants born small for gestational age (SGA) have increased risk for metabolic syndrome. However, the physiologic role of irisin in neonates remains to be studied.
  
  
  OBJECTIVE
  To evaluate the association of umbilical cord blood irisin levels with gestational age and birth weight categories in neonates.
  
  
  METHODS
  A cross-sectional study of 341 newborns, from 26 to 41weeks' gestation. We collected umbilical cord blood and analyzed plasma for irisin by ELISA.
  
  
  RESULTS
  Plasma irisin levels were positively correlated with gestational age (r=0.21, p<0.001), and birth weight Z-score (r=0.18, p<0.001). SGA infants had significantly lower irisin (median [interquartile range] 55.38 [46.56-65.72]ng/mL) compared to appropriate for gestational age infants (64.41 [53.87-76.76]ng/mL) and large for gestational age infants (68.70 [54.78-79.09]ng/mL, p<0.01). The association between SGA and lower irisin remained significant in multivariate analysis independent of gestational age, maternal age, maternal BMI, and gestational diabetes (p=0.03). In singleton infants, irisin was also significantly negatively associated with maternal preeclampsia (p=0.01).
  
  
  CONCLUSIONS
  Our results support the notion that irisin may have a physiologic role in neonates. We speculate that decreased levels of irisin in SGA infants may contribute to the development of catch-up growth and metabolic syndrome later in life.
authors: Division of Newborn Medicine, Boston Children's Hospital, 300 Brookline Ave, Boston, MA, 02115, USA; Department of Pediatrics, Division of Neonatology, Goryeb Children's Hospital, 100 Madison Ave, Morristown, NJ, 07960, USA; Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 300 Brookline Ave, Boston, MA, 02215, USA; Harvard Medical School, 25 Shattuck St, Boston, MA, 02115, USA.
authors: Kyoung Eun
authors: KE
authors: Joung
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 300 Brookline Ave, Boston, MA, 02215, USA; Department of Family Medicine, Hallym University Sacred Heart Hospital, Hallym University, Gyeonggi-do, 431-070, Republic of Korea.
authors: Kyung-Hee
authors: KH
authors: Park
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 300 Brookline Ave, Boston, MA, 02215, USA.
authors: Andreas
authors: A
authors: Filippaios
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 300 Brookline Ave, Boston, MA, 02215, USA.
authors: Fadime
authors: F
authors: Dincer
authors: Division of Newborn Medicine, Boston Children's Hospital, 300 Brookline Ave, Boston, MA, 02115, USA; Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, 75 Francis St, Boston, MA, 02115, USA; Harvard Medical School, 25 Shattuck St, Boston, MA, 02115, USA. Electronic address: hchristou@partners.org.
authors: Helen
authors: H
authors: Christou
authors: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, 300 Brookline Ave, Boston, MA, 02215, USA; Section of Endocrinology, Division of Endocrinology, Boston VA Healthcare System, Jamaica Plain, MA, 02130, USA; Harvard Medical School, 25 Shattuck St, Boston, MA, 02115, USA.
authors: Christos S
authors: CS
authors: Mantzoros
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D001724:Birth Weight; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D047109:Fetal Development; D005353:Fibronectins / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D007328:Insulin / Q000097:blood; D008297:Male
chemical_list: D015415:Biomarkers; C577593:FNDC5 protein, human; D005353:Fibronectins; D007328:Insulin
keywords: Birth weight; Cord blood; Irisin; Newborn