Defect in cholesteryl ester transport in serum of patients with uremia receiving maintenance hemodialysis: Increased inhibitor activity for cholesteryl ester transfer

The rate of cholesterol transfer (RCT) from high-density lipoproteins (HDLs) to very low-density lipoproteins (VLDLs) and low-density lipoproteins (LDLs) was previously found to be lower In the serum of patients with uremia receiving maintenance hemodialysis than in the serum of control subjects, and the defect was associated with the serum density >1.063 gm/ml fraction (Hsla et al. J Lab Clin Med 1985,106:53). The present study shows that cholesterol transfer from HDLs to VLDLs and LDLs could be Increased when the lipoprotein-deficient fraction of control serum was substituted for the patients' fraction. Cholesteryl ester transfer protein (CETP) activity in patient serum was assayed and found to be below that in the serum of control subjects. CETP and CETP inhibitor activities in patient and control sera were separated by hydrophobic chromatography on phenyl-Sepharose. Recovery of CETP activity from patient samples was 214% ± 62%, and that from controls was 112% ± 15%. The data indicate that the low RCT of patients was caused by increased levels of an inhibitor to CETP activity in their serum.