Compositions of Serum Lipids, Lipoproteins, and Lipoprotein Fatty Acids in Type IV Primary Hypertriglyceridemia.

Abstract

The overall composition of serum lipoproteins and the fatty acid composition of cholesterol esters and phospholipids in the VLDL, IDL, LDL, and HDL were studied in eleven patients with familial type IV primary hypertriglyceridemia. The patients were divided into two groups: HTG 1 (serum triglycerides below 350mg/dl: 200-294, n=5) and HTG2 (serum triglycerides above 350mg/dl: 368-820, n=6). The data were compared with those from 9 normolipidemic subjects.The proportion of the constituents of VLDL was normal in the HTG1 group, but cholesterol esters were increased and triglycerides decreased in this fraction in the HTG2 one. The increase in triglycerides and decrease in cholesterol esters in LDL and HDL modified the CE/TG and TG/total lipoprotein ratios in both groups of patients. The core lipid/surface ratio was increased in HDL in both groups, but not in the other three fractions.The saturated fatty acids of cholesterol esters were low (p<0.01) in the VLDL of the HTG2 group. The ω6 fatty acids of cholesterol esters and phospholipids were slightly increased (p<0.05) in the VLDL in the same group. However, there was a decrease in the ω6 fatty acids in cholesterol esters (p<0.05) and in the phospholipids (p<0.01) in the IDL of the HTG1 group. There was no significant difference in the LDL fatty acid composition between the hypertriglyceridemic patients and the controls. The phospholipids of the HDL in the HTG2 group contained less (p<0.05) saturated fatty acids and more (p<0.05) polyunsaturated fatty acids than did those in the HTG1 group.These observations suggest that the fatty acid composition of lipoproteins in hypertriglyceridemic subjects is not markedly altered and is not related to the major changes in the lipoprotein composition of their fractions.