Properties of lipoprotein complexes isolated by affinity chromatography from human aorta

We have isolated from the same human aortic intima-media, using a sequential extraction procedure and affinity column chromatography, different ApoLDL-containing lipoprotein complexes. The neutral lipid composition of the fractions retained by the anti-ApoLDL immunoglobulin, from saline extracts and elastase-treated samples, was similar to that of plasma low density lipoproteins. The fatty acids of phosphatidylcholine, triglycerides and cholesterol esters of all three fractions have a lower content of linoleic acid than plasma low density lipoproteins. By electron microscope the three lipoprotein fractions appeared polydisperse. All the fractions contained particles in the density range of low density plasma lipoproteins but those from elastase extracts and guanidinium-HC1 extracts contained also lipoproteins with densities below 1.019 g/ml. We found large variation in the composition of fractions from different aortas. The lipoproteins isolated from buffered saline were found associated with 2 to 4 micrograms of glycosaminoglycan (GAG) per 100 micrograms of protein. The associated GAG was made of chondroitin-6-SO4, dermatan and chondroitin-4-SO4 in a 3:2:1 ratio.