Pulmonary NO synthase expression is attenuated in a fetal baboon model of chronic lung disease

• Published in: American journal of physiology. Lung cellular and molecular physiology Vol. 284; no. 5; pp. 749 - L758
• Main Authors: Afshar, Sam, Gibson, Linda L, Yuhanna, Ivan S, Sherman, Todd S, Kerecman, Jay D, Grubb, Peter H, Yoder, Bradley A, McCurnin, Donald C, Shaul, Philip W
• Format: Journal Article
• Language: English
• Published: United States 01.05.2003
• Subjects: Animals; Animals, Newborn; Breath Tests; Chronic Disease; Disease Models, Animal; Female; Lung - embryology; Lung - enzymology; Lung Diseases - metabolism; Nitric Oxide - metabolism; Nitric Oxide Synthase - biosynthesis; Nitric Oxide Synthase - metabolism; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Papio; Pregnancy
• ISSN: 1040-0605; 1522-1504
• DOI: 10.1152/ajplung.00334.2002

1  Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75390; 2  San Antonio Military Pediatric Center, Lackland Air Force Base 78235; and 3  The Southwest Foundation for Biomedical Research, San Antonio, Texas 78245 Nitric oxide (NO), produced by NO synthase (NOS), serves multiple functions in the perinatal lung. In fetal baboons, neuronal (nNOS), endothelial (eNOS), and inducible NOS (iNOS) are all primarily expressed in proximal respiratory epithelium. In the present study, NOS expression and activity in proximal lung and minute ventilation of NO standard temperature and pressure ( E NO STP ) were evaluated in a model of chronic lung disease (CLD) in baboons delivered at 125 days (d) of gestation (term = 185 d) and ventilated for 14 d, obtaining control lung samples from fetuses at 125 or 140   d of gestation. In contrast to the normal 73% increase in total NOS activity from 125 to 140 d of gestation, there was an 83% decline with CLD. This was related to marked diminutions in both nNOS and eNOS expression and enzymatic activity. nNOS accounted for the vast majority of enzymatic activity in all groups. The normal 3.3-fold maturational rise in iNOS protein expression was blunted in CLD, yet iNOS activity was elevated in CLD compared with at birth. The contribution of iNOS to total NOS activity was minimal in all groups. E NO STP remained stable in the range of 0.5-1.0 nl · kg 1 · min 1 from birth to day 7  of life, and it then rose by 2.5-fold. Thus the baboon model of CLD is characterized by deficiency of the principal pulmonary isoforms, nNOS and eNOS, and enhanced iNOS activity over the first 2 wk of postnatal life. It is postulated that these alterations in NOS expression and activity may contribute to the pathogenesis of CLD. endothelial nitric oxide synthase; exhaled nitric oxide; inducible nitric oxide synthase; neuronal nitric oxide synthase; primate