Development, distribution, and lipid content of diet-induced atherosclerotic lesions of rhesus monkeys

• Published in: Experimental and molecular pathology Vol. 17; no. 1; pp. 38 - 54
• Main Authors: Manning, P.J., Clarkson, T.B.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.08.1972
• Subjects: Animals; Aorta - analysis; Aortic Diseases - pathology; Arteriosclerosis - etiology; Arteriosclerosis - pathology; Basilar Artery - pathology; Cholesterol - metabolism; Coronary Disease - pathology; Diet, Atherogenic; Haplorhini; Lipids - analysis; Lipids - blood; Macaca; Male; Mesenteric Arteries - pathology; Phospholipids - metabolism
• ISSN: 0014-4800; 1096-0945
• DOI: 10.1016/0014-4800(72)90056-1

Twenty-two rhesus monkeys were fed an atherogenic diet containing 1 mg of cholesterol/kcal for 4, 6, or 18 months. Serum total cholesterol, glycerides, and lipoprotein cholesterol were estimated at various intervals. At the end of each study period the monkeys were killed and the extent and severity of atherosclerosis were evaluated at necropsy and histopathologically. Specimens of normal-appearing aorta, fatty streaks, and atheromatous plaques from within each dietary group were pooled and aorta cholesterol, cholesteryl esters, triglycerides, and lipid phosphorous were measured. Four rhesus monkeys fed monkey food were examined similarly for comparison. All but one monkey fed the atherogenic diet had serum total cholesterol in excess of 600 mg/100 ml without hypertriglyceridemia. Betalipoproteins transported 95% of the serum total cholesterol. Thoracic aorta fatty streaks predominated in monkeys fed 4 or 6 months and abdominal aorta plaques were seen only in monkeys fed 18 months. Grossly visible coronary artery plaques were seen in 2 of 4 monkeys fed the diet 4 months, all 6 monkeys fed 6 months, and 11 of 12 monkeys on diet 18 months. Coronary artery atherosclerosis affected only the epicardial main coronary arteries. The concentration of aorta cholesterol of control monkeys was 2.1 mg/gm wet aorta, with 30% being cholesteryl esters, and the phospholipid cholesterol ratio was 2.41:1. Cholesterol accumulated in the aorta of cholesterol-fed monkeys to about 7 to 8 mg/gm before fatty streaks were visible to the unaided eye. The major alterations in lipid concentrations consisted of increases in total aorta cholesterol with a marked increase in cholesteryl esters which, in some pooled samples, exceeded the concentration of unesterified cholesterol. Phospholipids also accumulated in fatty streaks and plaques but to a lesser extent than cholesterol so that the decrease in phospholipid cholesterol ratio was greatest in aortic plaques.