Effects of Hypertension on the Lipid Composition of Rat Aortic Intima-Media

Abstract

Since hypertension intensifies the development of atherosclerosis, effects of hypertension on the lipid composition of aortic intima-media of male rats were studied. Concentrations of cholesterol, both esterified and unesterified, and of phospholipid were increased, and the concentration of triglyceride was decreased in aortas of hypertensive rats maintained on a stock diet. Changes in free cholesterol, phospholipid, and triglyceride are believed to be concomitants of medial hypertrophy, which was pronounced in aortas of hypertensive rats. Changes in esterified cholesterol, however, may be attributable to an influence of plasma lipids on aortic lipids. Cholesteryl ester, quantitatively a minor lipid component of the aorta, shows a larger increase with hypertension than other lipid classes. The resemblance between fatty acid compositions of aortic and plasma cholesteryl esters was strong, and persisted when the composition of plasma cholesteryl esters was altered by diet. These results suggest that most of the aortic esters originated in the plasma, and support the concept that hypertension intensifies the development of atherosclerosis by increasing the net transfer of lipid from plasma to vessel.