Diet-induced atherosclerosis and experimental hypertension in stumptail macaques (Macaca arctoides). Effects of antihypertensive drugs and a non-atherogenic diet in the evolution of lesions.

This study was carried out to determine the evolution of atherosclerotic lesions during a therapeutic period during which regression might be appreciated. We produced aortic and coronary atherosclerosis in 27 young adult stumptail macaques (Macaca arctoides) by feeding a diet supplemented with 2% cholesterol and 25% fat. Hypertension was produced by bilateral or unilateral narrowing of the renal artery. After six months of this regimen, four monkeys were killed (group 1) and 23 monkeys were divided into three groups: group 2 received unsupplemented diet; group 3 received the same diet as group 2 and drug treatment for hypertension; group 4 was continued on the atherogenic diet and received antihypertensive drug treatment. The results indicate that deleting the atherogenic diet leads to a decrease in the lipid content of the lesions and a transformation of the lipid laden atherosclerotic plaques into lipid-poor, fibro-collagenous lesions, with a decrease in the amount of coronary luminal narrowing. Partial control of systolic hypertension by antihypertensive drugs did not accelerate the involution of the atherosclerotic lesions over the relatively short period of this study. No statistically significant correlation by regression analysis was observed between the level of blood pressure elevation, the plasma renin activity, or the degree of the drug response, and the severity and extent of the atherosclerotic lesions. Furthermore, severe arterial hypertension without an atherogenic diet (group 5) produced arteriosclerosis of the aorta, and intensified branch cushions in the coronary arteries, without inducing lipid deposition in either vascular bed.