Lipoprotein-hyaluronate associations in human aorta fibrous plaque lesions

Lipoproteins and glycosaminoglycans were isolated from human aorta fibrous plaque lesions by isotonic saline extraction and treatment with elastase. Hydrolysis by elastase, using suitable inhibitors of nonspecific proteases, yielded about twice the amount of cholesterol and four times more GAG than saline extraction. Bio-Gel A-50m column chromatography of elastase-solubilized materials gave a fraction which contained lipoproteins of 1.006 and 1.063 floating densities and hyaluronic acid. Immunologically the lipoproteins resembled serum apoB-containing lipoproteins. Two species of hyaluronates with estimated molecular weights of 400,000 and 75,000 were observed. In addition to hyaluronate, elastase solubilized other GAG which were not associated with lipoproteins. Association of hyaluronate as the only GAG in the elastase-solubilized lipoprotein fraction emphasizes the important role that hyaluronate may play in the aggregation or entrapment of macromolecules such as lipoproteins in the arterial connective tissue matrix.