Cholesterol Ester Transfer Protein in Children on Peritoneal Dialysis

Abstract

To examine whether cholesterol ester transfer protein (CETP) activity and mass contribute to dyslipidemia in children on peritoneal dialysis (PD), and to determine whether CETP activity or mass is responsible for severer hyperlipidemia in smaller (younger) patients. 27 patients (18 males, 9 females; mean age 11.8 +/- 6.1 years) were enrolled. Each patient had been receiving PD for more than 6 months. Fasting blood samples were drawn and CETP activity, CETP mass, total cholesterol, triglyceride, beta-lipoprotein profiles, lipoprotein lipid profiles (cholesterol and triglyceride in lipoproteins), apoprotein profile, and serum albumin levels were measured. The results were then compared, using Student's t-test, with those for a control group. In the patient group, the relationships between CETP activity and each factor were examined using simple and multiple regression analyses. Total cholesterol, triglyceride, low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), chylomicron, and ApoB levels were significantly higher in the patient group. Mean CETP activity levels were 106% +/- 24% in the patient group and 111% +/- 21% in the control group. No significant difference in CETP activity was seen between the two groups, but CETP mass was lower in the patient group than in the control group (2.2 +/- 0.6 microL/dL for the patient group vs 2.8 +/- 0.9 microL/dL for the control group, p = 0.01). As a result, specific CETP activity (activity/protein mass ratio) was significantly higher in the patient group (p < 0.0001). CETP activity was positively related to LDL and other atherogenic factors and negatively related to serum albumin level. No relationship between CETP activity and patient body weight was seen. Specific CETP activity was higher in the patient group compared with that in the control group, and strong correlations were found between CETP activity and atherogenic factors in the patient group. Therefore, CETP seems to be associated with lipid abnormalities in children on PD but is not responsible for the severer hyperlipidemia seen in smaller children.