[Metabolism of long chain fatty acids in the normal and pathologic heart: effects of ischemia]

Abstract

Long-chain free fatty acids which, in well-oxygenated hearts are the preferred metabolic fuel, are detrimental to cardiac function under ischemic conditions. A number of metabolic products accumulate in the cell during ischemia, among which are the long-chain acyl esters of CoA and carnitine. The presence of exogenous fatty acids during ischemic perfusion results in higher tissue levels of acyl carnitine. Diabetic hearts also have higher tissue levels of long-chain acyl-CoA and acyl carnitine. Moreover the increase of these long-chain acyl esters during ischemia is greater than in the normal hearts. The rise in long-chain acyl carnitine levels in the ischemic tissue correlates with the appearance of amorphous densities in the mitochondria and with structural alteration of the inner mitochondrial membrane. Accumulation of intermediates of fatty acid metabolism likely to contribute to cellular damage during ischemia.