Serum Lipid and Lipoprotein Concentrations in Chronic Uremia

Abstract

The concentrations of triglycerides and cholesterol were determined in total serum and in the 3 major serum lipoprotein classes, i.e., very low (VLDL), low (LDL) and high (HDL) density lipoproteins, after an overnight fast in 39 patients with chronic uremia of more than 2 yr duration and with serum creatinine above 350 .mu.mol/l. The values were compared with data from healthy male and female controls. The findings were similar for male and female uremics. Hypertriglyceridemia was common while serum cholesterol tended to be normal or subnormal. With the conventional typing system for hyperlipidemia, types IIA, III and IV were present in 6, 9 and 30%, respectively. The triglyceride and cholesterol concentrations in VLDL were increased, while their normal relation for this lipoprotein class was maintained. In LDL the concentration of triglycerides was increased, while that of cholesterol was low. The LDL composition was more triglyceride-rich than normal. The changes in concentration and composition of LDL indicated that the levels of LDL1 were raised and of LDL2 decreased in chronic uremia. Increased levels of LDL triglycerides occurred more frequently (40%) than increased levels of VLDL triglycerides (33%). The most striking and consistent lipoprotein abnormality was a low HDL cholesterol, which was not related to high VLDL levels. The HDL triglycerides tended to be somewhat high. The importance of the raised levels of the triglyceride-rich VLDL and LDL1 and the decreased levels of HDL cholesterol for the rapid development of atherosclerotic vascular diseases which occur in chronic uremia is discussed. It is of interest in this context that both total cholesterol and LDL cholesterol were low. The complex mechanisms underlying the lipoprotein abnormalities in chronic uremia are discussed.