Lipid accumulation in the myocardium during acute regional ischaemia in cats.

Accumulation of lipid material in the myocardium was studied in cat hearts with acute regional ischaemia of 3 h duration. The fractional volume of lipid droplets in cytosol was analysed by electron microscopy of myocardial biopsies using a quantitative stereologic technique. Ischaemic and normally perfused myocardium were identified by fluoresceine injection, and tissue blood flow measurements were performed with labelled microspheres. In normal myocardium only small amounts of lipid droplets were found. A marked accumulation of lipid droplets occurred in borderline tissue between the two types of myocardium, whereas lipid accumulation in ischaemic myocardium was less pronounced. The arterial concentration of nonesterified fatty acids was clearly increased during the 3 h coronary artery occlusion period. Increased triglyceride synthesis from arterial fatty acids, or redistribution of intracellular lipids, are suggested as possible explanations for lipid accumulation during acute myocardial ischaemia.