Document Detail


Hypoxia impairs systemic endothelial function in individuals prone to high-altitude pulmonary edema.
MedLine Citation:
PMID:  15947284     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
RATIONALE: High-altitude pulmonary edema (HAPE) is characterized by excessive pulmonary vasoconstriction and is associated with decreased concentrations of nitric oxide (NO) in the lung. Objectives: We hypothesized that individuals susceptible to HAPE (HAPE-S) would also have dysfunction of the vascular NO vasodilator pathway during hypoxia in the systemic vasculature. METHODS: During normoxia (FI(O(2)) = 0.21) and 4 hours of normobaric hypoxia (FI(O(2)) = 0.12, corresponding to an altitude of 4,500 m above sea level) endothelium-dependent and endothelium-independent vasodilator responses to intraarterial infusion of acetylcholine (ACh) and sodium nitroprusside, respectively, were measured by forearm venous occlusion plethysmography in nine HAPE-S subjects and in nine HAPE-resistant control subjects. MAIN RESULTS: Pulmonary artery systolic pressure increased from 22 +/- 3 to 33 +/- 6 mm Hg (p < 0.001) during hypoxia in control subjects, and from 25 +/- 4 to 50 +/- 9 mm Hg in HAPE-S subjects (p < 0.001). Despite similar responses during normoxia in both groups, ACh-induced changes in forearm blood flow markedly decreased during hypoxia in HAPE-S subjects (p = 0.01) but not in control subjects. The attenuated vascular response to ACh infusion during hypoxia inversely correlated with increased pulmonary artery systolic pressure (p = 0.04) and decreased plasma nitrite correlated with attenuated ACh-induced vasodilation in HAPE-S subjects (p = 0.02). CONCLUSIONS: Hypoxia markedly impairs vascular endothelial function in the systemic circulation in HAPE-S subjects due to a decreased bioavailability of NO. Impairment of the NO pathway could contribute to the enhanced hypoxic pulmonary vasoconstriction that is central to the pathogenesis of HAPE.
Authors:
Marc M Berger; Christiane Hesse; Christoph Dehnert; Heike Siedler; Petra Kleinbongard; Hubert J Bardenheuer; Malte Kelm; Peter Bärtsch; Walter E Haefeli
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2005-06-09
Journal Detail:
Title:  American journal of respiratory and critical care medicine     Volume:  172     ISSN:  1073-449X     ISO Abbreviation:  Am. J. Respir. Crit. Care Med.     Publication Date:  2005 Sep 
Date Detail:
Created Date:  2005-09-08     Completed Date:  2005-11-15     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9421642     Medline TA:  Am J Respir Crit Care Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  763-7     Citation Subset:  AIM; IM    
Affiliation:
Department of Internal Medicine VI (Clinical Pharmacology and Pharmacoepidemiology), University of Heidelberg, Germany.
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MeSH Terms
Descriptor/Qualifier:
Acetylcholine / pharmacology
Adult
Altitude Sickness / etiology*
Anoxia / blood,  physiopathology*
Blood Pressure
Disease Susceptibility
Endothelin-1 / blood
Endothelium, Vascular / physiopathology*
Female
Forearm / blood supply
Hemodynamics
Humans
Male
Middle Aged
Nitrates / blood
Nitrites / blood
Nitroprusside / pharmacology
Pulmonary Artery / physiopathology
Pulmonary Edema / etiology*
Pulmonary Gas Exchange
Regional Blood Flow
Single-Blind Method
Vasodilation
Vasodilator Agents / pharmacology
Chemical
Reg. No./Substance:
0/Endothelin-1; 0/Nitrates; 0/Nitrites; 0/Vasodilator Agents; 15078-28-1/Nitroprusside; 51-84-3/Acetylcholine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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