HUMAN SERUM GANGLIOSIDES IN HYPERCHOLESTEROLEMIA, BEFORE AND AFTER EXTRACORPOREAL ELIMINATION OF LDL

Total content, pattern and transport by lipoproteins of gangliosides have been studied in the sera of 10 patients with hypercholesterolemia and manifest cardiovascular disease. Half of the patients with hypercholesterolemia and 3 healthy controls were treated with heparin-induced extracorporeal LDL precipitation (HELP). In the sera of the untreated group total gangliosides and cholesterol were elevated about 2-fold. Ratios of normal ganglioside components were not altered and abnormal ganglioside species not detected. Treatment with HELP resulted in an almost selective removal of lipid-bound sialic acid carried on LDL. The re-increase of total serum gangliosides was strictly correlated to that of LDL-cholesterol and apolipoprotein B. Total gangliosides and ratios of individual components carried on single LDL- and HDL-particles were not altered by the HELP treatment. Our results indicate that gangliosides are excreted into the serum along with nascent apolipoprotein B-containing lipoproteins, which are of hepatic origin. In hypercholesterolemia excretion of gangliosides into the circulation is elevated and surplus of circulating gangliosides is bound to increased numbers of 'atherogenic' LDL. Biosynthesis of different ganglioside components, most probably by the liver, and total amount of gangliosides bound to lipoprotein particles seem not to be altered.