Aortic atherosclerosis in normal and spontaneously diabetic Macaca nigra.

Aortic atherosclerosis is minimal in normal Macaca nigra; development of atherosclerosis correlates with increasing severity of diabetes mellitus. The extent of aortic involvement (plaque plus sudanophilia) was quantified and compared with metabolic and clinical parameters. Increasing atherosclerosis correlated with decreasing ability to clear glucose in a tolerance test (P less than 0.01), decreasing insulin (P = 0.02), and increasing glucose (P less than 0.01) and triglycerides (P less than 0.01). A diabetic index, established as a summation of several metabolic measurements, correlated with atherosclerosis at P less than 0.001. On the average, involvement of the thoracic aorta was about 3-fold greater than in the abdominal portion; involvement reached over 40% in severely diabetic monkeys. Atherosclerosis development is unique in these monkeys since they consume a natural ration low in fat and cholesterol. Serum cholesterol did not correlate with diabetes or artherosclerosis. Increasing age alone was associated with slight sudanophila, some intima-media thickening, and occasional small lesions. However, only with increasing severity of diabetes was there significant atherosclerosis.