STUDY OF ATHEROSCLEROSIS REGRESSION IN MACACA-MULATTA .1. DESIGN OF EXPERIMENT AND LESION INDUCTION

Rhesus monkeys were fed an atherogenic diet containing 40% of calories from lard and 1.0 mg/Cal cholesterol for either 19 months (Colony I) or 38 months (Colony II). At the end of the induction period the animals from each colony were divided into three groups (A, B, C) on the basis of total plasma cholesterol concentration during the induction period. Group A animals were killed at the end of the induction period for baseline observation of the extent and severity of atherosclerosis. Group B from each colony was fed a diet which maintained total mean plasma cholesterol concentrations between 280 to 320 mg/dl comparable to human beings with modest hyperlipoproteinemia. Group C from each colony was fed a diet which maintained total mean plasma cholesterol concentrations between 180 to 220 mg/dl, comparable to people who had modest hyperlipoproteinemia but were able to reduce plasma cholesterol concentrations by approximately 100 mg/dl using diet or drugs. Each group was further divided into two subgroups (B1, B2, and C1, C2). Animals from subgroup 1 were fed these diets for 24 months and animals from subgroup 2 were fed the same diet for 48 months. This report describes the clinical history, chemical analyses of arteries and the morphological extent and severity of atherosclerosis in arteries from animals of both colonies at the end of the induction period. © 1979.