Diet‐induced aortic atherosclerosis in Malaysian long‐tailed monkeys ( Macaca irus )

Moderate hypercholesterolaemia has been produced in eight adult male M. irus monkeys by feeding an egg-toast preparation containing butter and 0.14 per cent. total cholesterol. At autopsy, after two to four years of persistent hypercholesterolaemia, there was massive fatty streaking of the aorta involving 21 to 78 per cent. of the intimal surface. The distribution and morphology of the fatty streaks was similar to that in man. In addition, there were fibrous plaques including "soft" lipid-rich atherosclerotic plaques identical to their human counterpart. There was no grossly detectable thromobosis, haemorrhage or ulceration. Atherosclerotic lesions were also present in the coronary, carotid, subclavian, iliac and femoral arteries. In a control group of monkeys fed a low-fat, cholesterol-free diet, arterial lesions were identical in type and extent to those in freshly captured wild monkeys.