Abnormal pulmonary vascular tone in canine oleic acid lung injury.
OBJECTIVE
To characterize the endothelium-dependent and endothelium-independent components of abnormal pulmonary vascular tone in canine oleic acid lung injury.


METHODS
Prospective, interventional study.


METHODS
University laboratory.


METHODS
Twenty anesthetized mongrel dogs.


METHODS
Right heart catheterization was performed to measure pulmonary vascular resistance before and after induction of oleic acid lung injury in ten anesthetized and ventilated dogs. Pulmonary and internal mammary artery rings were sampled in these ten dogs with oleic acid injury and in ten anesthetized healthy control dogs. We also studied the responses to acetylcholine, to phenylephrine, and to hypoxia of the intact or endothelium-denuded rings mounted in organ baths.


RESULTS
Oleic acid lung injury was associated with an increase in pulmonary vascular resistance from 118 +/- 11 to 245 +/- 47 dyne.sec.cm-5.m-2 and a decrease in the Pao2/Fio2 ratio from 451 +/- 42 to 139 +/- 26 mm Hg (mean +/- se, p <.05 and p <.01, respectively). Acetylcholine-induced relaxation was decreased in the oleic acid pulmonary artery rings compared with the controls (85 +/- 3% vs. 99 +/- 6% of precontraction level, p <.05). Phenylephrine-induced contraction was decreased in denuded oleic acid pulmonary artery rings compared with the controls (81 +/- 8% vs. 102 +/- 10% of contraction to KCl 120 mM, p <.05). In vitro hypoxia induced a small endothelium-dependent contraction followed by an endothelium-independent relaxation. These responses were not different in oleic acid lung artery rings and in controls, except for a decrease in hypoxic contraction in the oleic acid pulmonary artery rings. In vitro hypoxic pulmonary vasoconstriction and relaxation were, respectively, directly (r =.48) and inversely (r = -.67) correlated with oleic acid-induced increase in pulmonary vascular resistance. There was no correlation between in vitro internal mammary artery reactivity and oleic acid-induced increase in pulmonary vascular resistance.


CONCLUSIONS
Oleic acid-induced lung injury slightly impairs pulmonary arterial endothelium-dependent relaxation and endothelium-independent contraction. In vitro hypoxic pulmonary vasoreactivity is related to in vivo oleic acid-induced increase in pulmonary vascular resistance.
Laboratory of Physiology, Free University of Brussels School of Medicine and Erasme University Hospital, Brussels, Belgium.
Sophia Abdel
SA
Kafi
Pietro
P
Scillia
Christian
C
Mélot
Pierre Alain
PA
Gevenois
Alberto
A
Pagnamenta
Robert
R
Naeije
D000818:Animals; D001784:Blood Gas Analysis; D004285:Dogs; D006439:Hemodynamics / Q000187:drug effects; D066298:In Vitro Techniques; D009129:Muscle Tonus; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology*; D019301:Oleic Acid / Q000008:administration & dosage / Q000494:pharmacology; D012128:Respiratory Distress Syndrome / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology*; D012720:Severity of Illness Index
D019301:Oleic Acid