1806 Molecular Mechanisms of Perinatal Lung Fluid Clearance in term Newborns

Background and Aim The perinatal switch from secretion to absorption in airway fluid transport includes increase in gene expression and activity of ion channels, e.g. apical amiloride-sensitive epithelial sodium channel (ENaC) and basolateral Na-K-ATPase. The serum- and glucocorticoid-induced kinase (SGK) may induce ENaC and Na-K-ATPase. Our objective was to study airway expression of SGK1, Na-K-ATPase α1-subunit and αENaC during adaptation in term infants. Methods 86 term infants (GA= 39.43±0.91; mean ± SD) were included in the study (vaginal delivery, VD, n=25 and elective cesarean section, CS, n=61). Within 3 hours and at 22–29 hours after delivery airway cell samples were obtained from the infants’ nasal epithelium. αENaC, Na-K-ATPase α1-subunit, and SGK1 mRNAs in the samples were quantified with real-time RT-PCR and normalized to cytokeratin 18 (CK18). Results ENaC and Na-K-ATPase α-subunit mRNA amounts were similar after VD and CS. During the first postnatal day Na-K-ATPase α1 gene expression decreased in infants delivered by CS (p