Low pulmonary expression of epithelial Na(+) channel and Na(+), K(+)-ATPase in newborn infants with congenital diaphragmatic hernia.
BACKGROUND
It has been suggested from several animal studies and clinical observations that congenital diaphragmatic hernia (CDH) with pulmonary hypoplasia is accompanied by a disturbed perinatal ion transport. This could lead to respiratory distress due to slower clearance of fetal lung fluid at birth.


OBJECTIVE
The purpose of this study was to determine whether CDH is related to changes in the expression of three rate-limiting transporter proteins in lung epithelium at birth.


METHODS
Tracheal aspirate was collected from 12 newborn infants with CDH and from 8 newborn control patients. Sampling was performed at postnatal age 18 and at 43 h in the CDH group and at 18 h in the control group. The protein abundance of α-, β- and γ-epithelial Na(+) channel (ENaC), aquaporin 5 and Na(+), K(+)-ATPase α(1) was analyzed using semiquantitative immunoblotting.


RESULTS
The levels of β-ENaC, γ-ENaC and Na(+), K(+)-ATPase α(1) collected at 18 h postnatally were significantly lower in CDH infants compared to control infants. In the CDH group, no significant difference in the expression of the ENaC subunits, Na(+), K(+)-ATPase α(1) or aquaporin 5 could be detected between the two sampling time points.


CONCLUSIONS
This downregulation may result in an abnormal lung fluid absorption which could be an important mechanism behind the respiratory distress seen in newborn CDH patients.
Ringman Uggla
Andreas
A
Nordic Centre of Excellence for Research in Water Imbalance Related Disorders, Karolinska Institutet, Stockholm, Sweden.
von Schewelov
Katarina
K
Zelenina
Marina
M
Aperia
Anita
A
Frenckner
Björn
B
D000015:Abnormalities, Multiple; D051402:Aquaporin 5 / Q000032:analysis / Q000378:metabolism*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D015536:Down-Regulation; D053503:Epithelial Sodium Channels / Q000032:analysis / Q000378:metabolism*; D005260:Female; D005865:Gestational Age; D006548:Hernia, Diaphragmatic / Q000201:enzymology* / Q000473:pathology; D065630:Hernias, Diaphragmatic, Congenital; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000201:enzymology* / Q000473:pathology; D008297:Male; D012121:Respiration, Artificial; D020545:Respiratory Mucosa / Q000201:enzymology* / Q000473:pathology; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis / Q000378:metabolism*
C496036:AQP5 protein, human; D051402:Aquaporin 5; D053503:Epithelial Sodium Channels; D000254:Sodium-Potassium-Exchanging ATPase