Effect of free fatty acid on pulmonary transvascular fluid and protein exchange.

We demonstrated the effect of infusion of oleic acid, a common free fatty acid, on pulmonary vascular permeability in anesthetized dogs prepared with a lung lymph fistula. Infusion of oleic acid caused significant increases in lung lymph flow with no change in L/P protein ratio, resulting in significant increases in transvascular protein clearance. Pulmonary arterial and pulmonary arterial wedge pressures increased significantly from baseline but their elevation was slight. Cardiac output decreased significantly after oleic acid infusion. In contrast to the effects of oleic acid, left arterial hypertension caused increases in lung lymph flow that were associated with decreases in the L/P protein ratio. Lung water content was increased after oleic acid infusion, despite little effect on pulmonary vascular pressures. These findings indicate that oleic acid produced endothelial lung injury and increased pulmonary vascular permeability.