The purpose of this study is the elucidation of the effects of dietary components and their interactions on lipid metabolism and atherogenesis. Using a cholesterol-free, semipurified diet we have shown that animal protein (A) is more atherogenic than plant or vegetable protein (V). We have posed the hypothesis that a protein's atherogenicity is due, in part, to the ratio of lysine/arginine (L/A) which is high in A and low in V. Addition of lysine to V increases its atherogenicity and addition of arginine to A decreases its atherogenicity. We propose to investigate characteristics of plasma apolipoproteins from rabbits fed diets containing A, V, A plus arginine or V plus lysine. Apoproteins will be analyzed by isoelectric focusing, and sequencing for component amino acids. The effects of LDL from rabbits fed these diets on cholesterol esterification by mouse macrophages will be studied as well. The products of in vivo and in vitro digestion of casein, soy protein, casein plus arginine and soy plus lysine will be studied by HPLC to ascertain if single amino acids perturb the spectrum of products of digestion. Lectins present in peanut oil may play a role in its well established atherogenicity. We will identify lectin binding sites in aortas of rabbits fed peanut or corn oils; proliferation of aortic smooth muscle cells will be studied in cells exposed to serum from rabbits fed peanut or corn oils. Plasma from rabbits fed peanut or corn oil will be studied for its chemotactic effect on macrophages. We will also compare the influence of fibers (pectin, guar gum, cellulose) on progression and regression of atherosclerosis in rabbits. The disciplines involved are nutrition, physiology, biochemistry and molecular biology. The question of dietary effects on serum lipid levels and atherosclerotic heart disease is a major public health concern. We plan to delineate the influences of single dietary components and of their interactions in an effort to provide clues to management of this disease.
