Blood Lipids and Human Atherosclerosis

Abstract

A quantitative assessment has been made of the relationship of certain previously described lipoproteins with atherosclerosis in the exptl. rabbit and in the human. Considering several exptl. procedures which allow for selective elevation of special classes of lipoproteins in the rabbit, it has been demonstrated that the lipoproteins designated as the Sf 10-30 class are highly associated with and universally concurrent with the development of atherosclerosis. The normally occurring lipoproteins of Sf 10 or less show no positive association with atheroma formation, nor do the cholesterol-bearing lipoproteins of Sf 100 or higher. Serum cholesterol itself is not related to the development of atherosclerosis in the rabbit, except in those special situations where the cholesterol elevation is primarily in the form of the Sf 10-30 class of lipoproteins. In the human 2 classes of lipoproteins are strongly associated with atherosclerosis. These are the Sf 12-20 and Sf 20-100 lipoproteins. Although these are partially interrelated, each provides an independent contribution to atherogenesis. Further these lipoproteins segregate patients with atherosclerotic coronary disease from normals, independent of serum cholesterol levels, as a result of the much stronger relationship of these particular lipoproteins with atherosclerosis than exists for the total serum cholesterol. Consideration of various obscuring factors operative in detn. of the association of lipoproteins with atherosclerosis indicates that the Sf 12-100 lipoproteins probably account for the vast bulk of the metabolic factors involved in atheroma formation. Preliminary (1 yr.) follow-up data indicate that occurrence of myocardial infarction de novo and recurrence of myocardial infarction in patients with established coronary disease are both positively associated with elevated Sf 12-20 lipoprotein levels. Reduction of Sf 12-20 levels in coronary patients with elevated levels provides some protection against further clinical sequelae of coronary atherosclerosis.