Use of aortic medial explants in the study of atherosclerosis

Abstract

An in vitro culture system having many of the features of early atherosclerosis has been developed. Explants of swine aortic media develop a peripheral growth with cellular and extracellular components similar to the early lesion, and show both cell proliferation and necrosis. Using this system it has been shown that aortic tissues themselves have differences in potential for both cell proliferation and cell death, and that swine sera differ in capability to cause cell death, cell proliferation, and the development of a peripheral growth. Either serum or aortic tissue derived from swine fed hypercholesterolemic diet results in more cell proliferation, but no differences in cell death. All swine sera contain, in varying amounts, factors, separable from such macromolecules as lipoproteins, which result in DNA synthesis, and DNA breakdown, and inhibit DNA synthesis. Human sera, when used in the swine explant assay, cause the same effects as normal swine sera, with generally greatly increased capacity for stimulating DNA synthesis. Studies of possible correlation between results of human serum assay in the explant system and angiographic evidence of coronary artery disease are in progress. In any studies of the effects of lipoprotein classes in any in vitro system, careful processing of lipoproteins to insure separation from the other serum DNA synthesis-stimulating and synthesis-inhibiting factors is imperative.