ATHEROSCLEROTIC PLAQUE REGRESSION IN RHESUS-MONKEYS INDUCED BY BILE-ACID SEQUESTRANT

This study in 10 rhesus monkeys was made to determine whether the bile acid sequestrant, cholestyramine (CST), when added to an atherogenic diet would cause regression of atherosclerotic plaques induced by dietary means. Sequential plaque changes were evaluated by serial angiography, surgical exploration, biopsy, and autopsy. After 23 months on atherogenic diet (Period I) all animals developed fatty fibrous plaques. CST was then added to the diet of eight animals over the following 11 months (Period II) and at the end of this interval seven showed plaque regression. One animal appeared to show regression of atherosclerosis in abdominal aortic branches and progression in the internal carotid artery. Atherosclerotic disease progressed in two control animals which were continued on the atherogenic diet alone during Period II. Overall, CST was effective in lowering cholesterol level sufficiently to induce plaque regression. During Period II, fecal bile acid excretion increased eight fold while average serum cholesterol fell from 400 ± 13 to 237 ± 70 mg/dl. Plaque regression appeared related to level of serum cholesterol during Period II rather than to the magnitude of increase of fecal bile excretion. © 1979.