Effects of experimental hypertension and hypercholesterolemia on the lipid composition of the aorta.

This study evaluates alterations in canine aortic lipid composition under conditions of hypertension, hypercholesterolemia, or a combination of these factors. Hypertension was produced in the proximal thoracic aorta by creation of an aortic coarctation, whereas hypercholesterolemia was brought about by a lard-cholesterol diet in combination with thyroidectomy. Hypertension alone produced only minor changes in the lipid content of the arterial wall, but hypercholesterolemia yielded modest increases. The combination of hypertension and hypercholesterolemia, however, produced a striking increase in the total lipid content in the arterial wall. This change was most marked in the cholesteryl ester fraction, and a shift in cholesteryl ester fatty acids from linoleate to oleate was found. These data indicate that the interaction of hypertension and hypercholesterolemia produces alterations in lipid composition in a relationship which appears to be more geometric than arithmetic in nature.