The Precipitation of Serum Lipoproteins by Mucopolysaccharides Extracted from Aortic Tissue †

Because of the frequent association of metachromatic staining material and lipid deposits within the artery wall, the suggestion has been made that the mucopolysaccharides of the connective tissue of arteries may in some way render lipids of the blood insoluble and thereby set the stage for the development of the lesions of arteriosclerosis." "' Studies in this laboratory have demonstrated the accumulation of intravenously injected lipoproteins or of chylomicrons in regions of focal arterial injury, where metachromatic materials are present.'" Analyses of sulfate content in human aortas suggest that sulfated polysaccharides may cause deposition of the lipids by some chemical interaction.'8 It is known that hyaluronic acid precipitates protein from diluted, acidified horse serum.'9'" Concentrated solutions of hyaluronic acid precipitate some protein from human plasma below pH 7.0.' Both hyaluronic acid and chondroitin sulfuric acid precipitate globin at neutral pH.""8 A number of recent studies have demonstrated a rather specific precipitation of plasma lipoproteins by sulfated polysaccharides; these include sulfated dextran,' heparin,7 agar agar,' and sulfated amylopectin.8 Dyrbye and Kirk'0"' have extracted various mucopolysaccharides from aortic tissue, identifying a relatively high percentage of sulfated polysaccharides. The in vitro precipitation of plasma lipoproteins by polysaccharides of the artery wall, to our knowledge, has not been demonstrated. An investigation of possible interactions between these substances was begun as part of a continuing investigation in this laboratory of the pathogenesis of arteriosclerosis.