Glycosaminoglycans inhibit the aortic uptake of very low density lipoproteins in rabbits

The in vitro uptake of very low density lipoproteins obtained from cholesterol-fed rabbits (VLDL-HC) has been investigated in aortic tissue and in cultured smooth muscle cells, grown from thoracic aorta of normal rabbits. The incorporation of 125I-VLDL-HC into fragments of aortic tissue increased with the concentration of incubated lipoproteins, with incubation time, with the amount of incubated tissue, and appeared to be temperature-dependent. Heparin and a mixture of glycosaminoglycans extracted from pig duodenum inhibit the aortic uptake of lipoproteins and decrease both cell surface binding and internalization of VLDL-HC in cultured aortic smooth muscle cells. Cell monolayers increased their content in cholesterol esters when incubated in the presence of lipoprotein-carried cholesterol, and this accumulation was partially prevented by glycosaminoglycans. These results provide further evidence that the inhibition of lipoprotein uptake by arterial wall may contribute to the claimed antiarteriosclerotic properties of exogenously administered glycosaminoglycans.