Defective lung vascular development and fatal respiratory distress in endothelial NO synthase-deficient mice: a model of alveolar capillary dysplasia?
Endothelium-derived NO plays a critical role in the regulation of cardiovascular function and structure, as well as acting as a downstream mediator of the angiogenic response to numerous vascular growth factors. Although endothelial NO synthase (eNOS)-deficient mice are viable, minor congenital cardiac abnormalities have been reported and homozygous offspring exhibit high neonatal mortality out of proportion to the severity of these defects. The aim of the present report was to determine whether abnormalities of the pulmonary vascular development could contribute to high neonatal loss in eNOS-deficient animals. We now report that eNOS-deficient mice display major defects in lung morphogenesis, resulting in respiratory distress and death within the first hours of life in the majority of animals. Histological and molecular examination of preterm and newborn mutant lungs demonstrated marked thickening of saccular septae, with evidence of reduced surfactant material. Lungs of eNOS-deficient mice also exhibited a striking paucity of distal arteriolar branches and extensive regions of capillary hypoperfusion, together with misalignment of pulmonary veins, which represent the characteristic features of alveolar capillary dysplasia. We conclude that eNOS plays a previously unrecognized role in lung development, which may have relevance for clinical syndromes of neonatal respiratory distress.
Han
Robin N N
RN
Terrence Donnelly Heart Center, Division of Cardiology, St Michael's Hospital and the Department of Medicine, University of Toronto, Toronto, Canada.
Babaei
Saeid
S
Robb
Malcolm
M
Lee
Tony
T
Ridsdale
Ross
R
Ackerley
Cameron
C
Post
Martin
M
Stewart
Duncan J
DJ
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D001485:Basement Membrane / Q000648:ultrastructure; D002196:Capillaries / Q000473:pathology; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005109:Extracellular Matrix / Q000648:ultrastructure; D005260:Female; D005326:Fetal Proteins / Q000172:deficiency / Q000502:physiology; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006133:Growth Substances / Q000096:biosynthesis / Q000235:genetics; D006330:Heart Defects, Congenital / Q000196:embryology / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D008098:Litter Size / Q000187:drug effects / Q000235:genetics; D008168:Lung / Q000196:embryology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009024:Morphogenesis; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology / Q000633:toxicity; D018919:Neovascularization, Physiologic / Q000235:genetics; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D011650:Pulmonary Alveoli / Q000098:blood supply*; D011663:Pulmonary Surfactants / Q000378:metabolism; D017978:Receptors, Growth Factor / Q000096:biosynthesis / Q000235:genetics; D012127:Respiratory Distress Syndrome, Newborn / Q000196:embryology / Q000201:enzymology* / Q000235:genetics
D004791:Enzyme Inhibitors; D005326:Fetal Proteins; D006133:Growth Substances; D011663:Pulmonary Surfactants; D017978:Receptors, Growth Factor; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D019331:NG-Nitroarginine Methyl Ester