title: Postnatal decrease in circulating insulin-like growth factor-I and low brain volumes in very preterm infants.
abstract: BACKGROUND
  IGF-I and IGF binding protein-3 (IGFBP-3) are essential for growth and maturation of the developing brain.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the association between postnatal serum concentrations of IGF-I and IGFBP-3 and brain volumes at term in very preterm infants.
  
  
  METHODS
  Fifty-one infants with a mean (sd) gestational age (GA) of 26.4 (1.9) wk and birth weight (BW) of 888 (288) g were studied, with weekly blood sampling of IGF-I and IGFBP-3 from birth until 35 gestational weeks (GW) and daily calculation of protein and caloric intake. Magnetic resonance images obtained at 40 GW were segmented into total brain, cerebellar, cerebrospinal fluid, gray matter, and unmyelinated white matter volumes.
  
  
  METHODS
  We evaluated brain growth by measuring brain volumes using magnetic resonance imaging.
  
  
  RESULTS
  Mean IGF-I concentrations from birth to 35 GW correlated with total brain volume, unmyelinated white matter volume, gray matter volume, and cerebellar volume [r = 0.55 (P < 0.001); r = 0.55 (P < 0.001); r = 0.44 (P = 0.002); and r = 0.58 (P < 0.001), respectively]. Similar correlations were observed for IGFBP-3 concentrations. Correlations remained after adjustment for GA, mean protein and caloric intakes, gender, severe brain damage, and steroid treatment. Protein and caloric intakes were not related to brain volumes. Infants with BW small for GA had lower mean concentrations of IGF-I (P = 0.006) and smaller brain volumes (P = 0.001-0.013) than infants with BW appropriate for GA.
  
  
  CONCLUSIONS
  Postnatal IGF-I and IGFBP-3 concentrations are positively associated with brain volumes at 40 GW in very preterm infants. Normalization of the IGF-I axis, directly or indirectly, may support normal brain development in very preterm infants.
authors.affiliation: Division of Pediatrics, Department of Clinical Sciences, Lund, Lund University Hospital, 221 85 Lund, Sweden. ingrid.pupp@skane.se
authors.forename: Ingrid
authors.initials: I
authors.lastname: Hansen-Pupp
authors.forename: Holger
authors.initials: H
authors.lastname: Hövel
authors.forename: Ann
authors.initials: A
authors.lastname: Hellström
authors.forename: Lena
authors.initials: L
authors.lastname: Hellström-Westas
authors.forename: Chatarina
authors.initials: C
authors.lastname: Löfqvist
authors.forename: Elna-Marie
authors.initials: EM
authors.lastname: Larsson
authors.forename: Francois
authors.initials: F
authors.lastname: Lazeyras
authors.forename: Vineta
authors.initials: V
authors.lastname: Fellman
authors.forename: Petra S
authors.initials: PS
authors.lastname: Hüppi
authors.forename: David
authors.initials: D
authors.lastname: Ley
mesh_terms: D001921:Brain / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D015331:Cohort Studies; D015536:Down-Regulation; D005260:Female; D005865:Gestational Age; D006801:Humans; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood* / Q000378:metabolism / Q000502:physiology; D019102:Infant, Very Low Birth Weight / Q000097:blood / Q000378:metabolism / Q000502:physiology; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D011859:Radiography
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I