Abstract
Background: ENaC is considered critical for the movement of liquid across respiratory epithelium. Functional impairment of liquid transport may participate in the pathogenesis of respiratory insufficiency. In preterm infants with respiratory distress syndrome ENaC expression is lower than in healthy term infants. We wanted to study how expression of ENaC changes over the first postnatal days.
Methods: We studied 35 healthy term infants (GA 39.5±1.3 wks). Samples of respiratory epithelium were obtained by scraping both nostrils at 1–4, 23–27 and 45–48 hours after birth. The samples were subjected to RT-PCR using real-time PCR for analysis of expression of alpha-, beta- and gamma-ENaC and cytokeratin 18 (CK18) which was used as an epithelial marker. Reactions were performed in singleplex format.
Results: In healthy term infants expression of alpha-ENaC was 8.2±4.0, 7.7±6.6 and 7.5±5.9 amol/fmol CK18 at 1–4, 23–27 and 45–48 hours after birth, respectively. Expression of beta-ENaC decreased significantly during the first 27 postnatal hours from 12.0±8.1 to 4.1±4.2 amol/fmol CK18 (p= 0.0001). At 45–48 hours after birth beta-ENaC was 2.7±3.6 amol/fmol CK18. Expression of gamma-ENaC was 19.2±34.9, 8.7±23.6 and 27.5±101.6 at 1–4, 23–27 and 45–48 hours after birth, respectively.
Conclusion: In the healthy newborn infant, expression of alpha- and gamma-ENaC remain constant over the first 48 postnatal hours, whereas there is a significant decrease in the expression of beta-ENaC. Beta-ENaC has been considered to have a regulatory function in the ENaC complex. We conclude that the expression of beta-ENaC may play a role in the postnatal pulmonary adaptation of the healthy newborn infant.
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Helve, O., Andersson, S., Kirjavainen, T. et al. 108 Expression of Epithelial Sodium Channel (ENAC) in The Airways of Healthy Term Infants During The First Postnatal Days. Pediatr Res 56, 482 (2004). https://doi.org/10.1203/00006450-200409000-00131
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DOI: https://doi.org/10.1203/00006450-200409000-00131