There is no clear rule about the progression of atherosclerosis. But, it is well known that the increase in serum lipids, especially cholesterol relates with atherosclerosis.
In present study, the content of lipids, fatty acid composition and phospholipid fraction in human aorta of adult and elderly were determined in order to examine the relationships between lipids and the progression of atherosclerosis.
Human aorta obtained at autopsy was frozen by liquid CO₂ and sectioned into intima, intimal media and media by cryostat. The each section was homogenized and the lipids were extracted with chloroform-methanol mixture and analyzed using thin-layer chromatography and gas-liquid chromatography.
In atherosclerotic lesion of adult, the contents of lipid were larger than in intact aorta. But compared with atherosclerotic lesion of elderly its progress was slow, and the rate of lipid increase, especially cholesterol was little.
In intact human aorta of elderly, especially in intima the contents of lipid were larger than in intact aorta of adult.
Compared with intact human aorta of adult, in intact of elderly and atherosclertic lesion of adult, the proportion of polyunsaturated fatty acid in phospholipid decreased, and lysolecithin increased in phospholipid fractions.
In fatty acid composition of cholesterolester, linoleic acid increased and oleic acid decreased in proportion to the distance from luminal surface. This tendency was remarkable with aging or progression of atherosclerosis.
From above findings, it was suggested that the balance between cholesterol and phospholipid, and the changes of polyunsaturated fatty acid in arterial wall played important rule in the progression of atherosclerosis.