[Experimental models of atherosclerosis. Contribution, limits and trends]

Abstract

Experimental approaches to the problem of atherosclerosis involve animal or cellular models and procedures of lesional induction. Relevant animal models are rare. The rat, the mouse and the dog are free of "natural" atherosclerosis and only develop diffuse lipidosis after high cholesterol diet and thyroid block. They are more appropriate models of experimental arteriosclerosis and intimal proliferation induced by different procedures. The rabbit, also free of spontaneous atherosclerosis, is extremely sensitive to lipid-rich diets, but the lesions induced resemble more a xanthomatosis than an atherosclerosis. Immunological procedures in this model result in a generalised immune arteriosclerotic arteriopathy. The monkey and pig, which are phylogenetically close to man, develop spontaneous atherosclerosis exacerbated by lipid-rich diets or other procedures: hormones, psychosocial stress. The cost and problems of upkeep make these two models inaccessible to most laboratories. Although the hen, turkey and pigeon are grain-eating, they develop natural atherosclerosis, are sensitive to atherogenic diets, and provide satisfactory replacement models, especially for research into the viral and tumoral theories of atherogenesis. The pigeon is particularly suitable for studying cellular, biochemical and genetic aspects of atherosclerosis: these spontaneous plaques, similar to those in man, are ontogenetically and topographically predictable. The species include genetic types both sensitive and resistant to the disease. Moderately lipid-rich diets induce lesions even in very young pigeons. They also lend themselves well to the study of the antiatherosclerotic effects of pharmacological agents. Endothelial, smooth muscle and macrophage cell cultures are widely used to study the factors influencing cellular modulation and proliferation, lipid metabolism and movement of cholesterol, cellular biosynthesis and cell-cell and cell-matrix interactions.