Effect of High Plasma Free Fatty Acids on the Free Radical Formation of Myocardial Mitochondria Isolated from Ischemic Dog Hearts

Abstract

Effects of high plasma free fatty acids (FFA) on the free radical formation of myocardial mitochondria, isolated from normal and ischemic dog hearts, were studied by electron spin resonance (ESR) spectrometry.
Free radical concentrations in state 4 respiration were used for the evaluation of the function in the mitochondria in this study. High plasma FFA levels were induced either by intravenous injection of Intralipid and heparin, or by infusion of norepinephrine. Ischemic hearts were induced by inserting a Cournand's 7F catheter into the left coronary artery under fluoroscopic control.
Exogenous high plasma FFA induced by Intralipid and heparin caused the decrease of free radicals in state 4 respiration in the mitochondria isolated from normal and ischemic dog hearts. Endogenous high FFA induced by continuous infusion of norepinephrine also caused the decrease of free radicals. On the other hand, nicotinic acid prevented the decrease of free radicals as well as the rise of plasma FFA by the norepinephrine infusion.
These results suggest that high plasma FFA itself, whether it may be exogenous or endogenous, may impair the oxidative phosphorylation of the mitochondria isolated from normal and ischemic hearts