Expression of heme oxygenase-1 and endothelial nitric oxide synthase in the lung of newborns with congenital diaphragmatic hernia and persistent pulmonary hypertension.
OBJECTIVE
Heme oxygenase (HO-1), an inducible isoform of HO is a regulator of vascular tone and cell proliferation through the production of endogenous carbon monoxide (CO). Endothelium-derived nitric oxide (NO) occurs in the endothelial layers of blood vessels and mediates vasorelaxation. Both CO and NO have similar properties and are potent vasodilators. The aim of this study was to examine the expression of HO-1 and endothelial nitric oxide synthase (eNOS) in the Congenital diaphragmatic hernia (CDI) lung.


METHODS
RNA was extracted from archival formalin-fixed paraffin-embedded lung tissue from 11 patients with CDH complicated by persistent pulmonary hypertension (PPH). Five age-matched newborns served as controls. Reverse transcription polymerase chain reaction (RT-PCR) was performed using specific primers for human HO-1 and eNOS. Immunohistochemistry using HO-1 and eNOS antibodies was performed and examined using laser scanning microscope.


RESULTS
HO-1 and eNOS mRNA expression was significantly decreased in CDH lung compared with controls (P <.05). HO-1 and eNOS immunoreactivity was reduced markedly reduced in the endothelium and arterial wall in the CDH samples compared with normal lung.


CONCLUSIONS
Decreased expression of HO-1 and eNOS in the CDH lung suggests deficiency of endogenous NO and CO, which may contribute to altered vascular tone causing PPH.
Children's Research Centre, Our Lady's Hospital for Sick Children and University College Dublin, Dublin, Ireland.
Valeria
V
Solari
Anna Piaseczna
AP
Piotrowska
Prem
P
Puri
D000704:Analysis of Variance; D016022:Case-Control Studies; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006548:Hernia, Diaphragmatic / Q000150:complications / Q000201:enzymology; D065630:Hernias, Diaphragmatic, Congenital; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000201:enzymology*; D008565:Membrane Proteins; D018613:Microscopy, Confocal; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D010547:Persistent Fetal Circulation Syndrome / Q000150:complications / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction
D008565:Membrane Proteins; D012333:RNA, Messenger; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1