Arterial Lesions in the Kenya Baboon

Abstract

One hundred sixty-three baboons ( Papio doguera were sacrificed and autopsied immediately after being trapped in their natural habitat in Kenya, British East Africa. Approximately three-fourths of the 67 adults had some degree of aortic intimal lipid deposition, as indicated by gross Sudan IV staining, and a few animals had extensive fatty streaks. These fatty streaks were more frequent with advancing age, but there was no sex difference. Electron microscopy disclosed most of the intimal lipid droplets to be intracellular. Fibrous plaques were infrequent and had a variable but usually low lipid content. One elderly male had fibrous plaques with hemorrhage into their bases. Histologic sections of the coronary arteries showed many small musculo-elastic intimal plaques in which lipid could only rarely be demonstrated. The aortic intimal lipid deposits cannot be attributed to the consumption of excessive animal fat or to hypercholesterolemia. These results indicate that the baboon, like man, is highly susceptible to arterial intimal lipid deposition and that it promises to be an excellent animal for the experimental investigation of atherosclerosis. They further more caution that adequate controls be used in all experimental work involving arterial lesions in primates.