Psychosocial influences on the pathogenesis of atherosclerosis among nonhuman primates

Epidemiologic and clinical evidence derived from studies of human beings suggests that psychosocial phenomena may account for much of the variability in atherosclerosis extent and severity that is unexplained by the "traditional" risk factors (serum lipids, hypertension, and smoking). Animal preparations provide an opportunity to test hypotheses concerning the role of psychosocial phenomena in atherogenesis and to explore the mechanisms by which the effects of such phenomena are mediated. Here we review a relatively large series of studies of cynomolgus monkeys (Macaca fascicularis), a 5 kg animal having a complex social organization. The data indicate that, among male animals, individual behavior characteristics (social status and aggressiveness), physiologic responsiveness to psychological challenge, and stability of the social environment all interact to affect atherogenesis. Among female animals, individual patterns of aggressiveness appear to influence ovarian function, which in turn affects atherosclerosis. Future advances in the behavioral medicine aspects of atherogenesis are likely to arise through elucidation of the pathophysiologic pathways by which these behavioral responses and characteristics contribute to the events (endothelial injury, smooth muscle cell proliferation, lipid accumulation, calcification, and necrosis) associated with plaque pathogenesis. Such research can be pursued in studies utilizing nonhuman primates as well as in complementary studies involving human subjects.