Lipid and fatty-acid composition of plasma lipoproteins in cases of aortic atherosclerosis

Abstract

Summary Cohn's method 10 has been used to obtain protein fractions IV + V and I + II + III from the plasma of normal young men and from men shown by aortography to be suffering from severe atherosclerosis of the aorta. Lipids extracted from these protein fractions (referred to for convenience as a- and β -lipids respectively) were separated into phospholipids, free cholesterol plus glycerides, free fatty acids and cholesterol esters; the fatty-acid composition of these four fractions was determined by gas-liquid chromatography and the composition of the phospholipids by chromatography on silica-impregnated paper. All the atherosclerotic subj ects were mildly to moderately hyper- β -lipoproteinaemic, the a-lipoprotein level (and composition) being the same as in normal controls. The β -lipids from subjects with aortic atherosclerosis were slightly modified in composition, having a higher sphingomyelin and lower free fatty acid content than those from the controls. The fatty-acid compositions of corresponding fractions (cholesterol esters, glycerides, etc.) of a- and β -lipids were virtually identical, both in normal and atherosclerotic individuals. In spite of a wide individual variation, a lower linoleic acid content of the cholesterol ester fatty acids of atherosclerotic subjects could be established. The possibility that the differences found were wholly or in part due to age differences between patients and controls cannot be excluded. Not all the lipid differences observed parallel those found by other authors using clinical symptoms of ischaemic heart disease as criteria for the existence of atherosclerosis.