Cholesteryl ester composition and morphology of human normal intima and fatty streaks

Abstract

The cholesteryl ester fatty acid composition and morphology of aorta and coronary artery fatty streaks and normal tissue have been studied in 13 cases of accidental death ranging in age from 17 to 37 years. The proportions of palmitic, oleic, and eicosatrienoic acids were higher, and the proportions of linoleic and arachidonic acids were lower in the cholesteryl esters from fatty streaks compared with grossly normal areas. This direction of difference in relative proportions of fatty acids was constant in every case, but the magnitude of the difference was variable. Cholesteryl oleate and linoleate showed changes of the greatest magnitude. The elevation in the proportion of cholesteryl oleate and depression in the proportion of cholesteryl linoleate was greatest when fatty streaks were compared with grossly normal tissue when the fatty streaks were composed of large numbers of foam cells. Differences in the proportions of the fatty acids esterified to cholesterol in the aorta and coronary arteries were similar when the lesions were similar histologically. Morphologic studies with the light and electron microscopes revealed a fine granular extracellular lipid and fusiform-shape cells with lipid in their cytoplasm in all fatty streaks and in most sections of normal tissue, but to a lesser degree. Lipid in these forms was correlated with a higher proportion of cholesteryl linoleate and lower oleate than was found in fatty streaks composed of large numbers of foam cells. The large foam cell in fatty streaks was observed to be distinctly different from smooth muscle cells.