title: Decreased sodium ion absorption across nasal epithelium of very premature infants with respiratory distress syndrome.
abstract: OBJECTIVE
  Successful adaptation to air breathing at birth depends on rapid absorption of fetal lung liquid that is mediated by activation of amiloride-sensitive sodium ion channels. To test the relationship between respiratory epithelial Na+ transport and development of respiratory distress syndrome (RDS), we measured nasal transepithelial potential difference (PD) in 31 very premature (< or = 30 weeks of gestation) newborn infants. Infants were retrospectively assigned to RDS (22 infants) and non-RDS (9 infants) groups on the basis of clinical and chest x-ray criteria.
  
  
  RESULTS
  Maximal nasal epithelial PD increased with birth weight (-1.2 mV/100 gm) and was lower in infants with RDS (-16.5 +/- 0.6 mV) than in those without RDS (-22.0 +/- 1.3 mV). Infants without RDS had PD values similar to normal fullterm infants. Amiloride inhibition of PD, an index of Na+ absorption, was significantly lower, within the first 24 hours of life, in infants in whom RDS developed (3.8 +/- 0.2 mV; 29.5% +/- 0.8% inhibition) than in those without RDS (6.1 +/- 0.6 mV; 38.6% +/- 0.5% inhibition). Maximal and amiloride-sensitive PD returned to normal during the recovery phase of RDS.
  
  
  CONCLUSIONS
  We conclude that Na+ absorption across nasal epithelium increases with increasing birth weight and that impairment of Na+ absorption across the respiratory epithelia of very premature infants may contribute to the pathogenesis of RDS.
authors.affiliation: Department of Pediatrics and Medicine, University of North Carolina at Chapel Hill 27599-7220, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Barker
authors.forename: C W
authors.initials: CW
authors.lastname: Gowen
authors.forename: E E
authors.initials: EE
authors.lastname: Lawson
authors.forename: M R
authors.initials: MR
authors.lastname: Knowles
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D001693:Biological Transport, Active; D001724:Birth Weight; D016022:Case-Control Studies; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D009297:Nasal Mucosa / Q000378:metabolism*; D012127:Respiratory Distress Syndrome, Newborn / Q000209:etiology / Q000378:metabolism* / Q000628:therapy; D012964:Sodium / Q000378:metabolism*; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000378:metabolism
chemical_list: D026941:Sodium Channel Blockers; D015222:Sodium Channels; D000584:Amiloride; D012964:Sodium