Lipoprotein changes in children after liver transplantation: Mild hypertriglyceridemia and a decrease in HDL/HDL ratio

Abstract

Hyperlipidemia is frequently observed in patients who undergo renal, cardiac, bone marrow, or liver transplantation, and its contribution to the long-term morbidity and survival of patients with organ transplants may be substantial. In the few studies that have focused on the pediatric age group, findings have been inconsistent. The lipoprotein profile of 10 children after liver transplantation was characterized and compared with those in normal population controls and 10 healthy siblings. Plasma triglyceride and cholesterol concentrations were determined, lipoprotein fractions (very-low-density lipoprotein [VLDL], low-density lipoprotein [LDL], and high-density lipoproteins [HDL₂and HDL₃]) were isolated, their chemical compositions were analyzed (protein, phospholipids, triglycerides, free cholesterol, and cholesteryl ester), and the percent relative weight composition of the particles was calculated. Plasma triglyceride and VLDL cholesterol levels were higher post-liver transplantation (P < .05): triglycerides (mean ± SD), 115.1 ± 58.7 mg% versus 76.6 ± 20.9 mg% in siblings and 60.0 ± 25.0 mg% in normal population controls; very-low-density lipoprotein cholesterol (VLDL-C), 23.0 ± 11.7 mg% versus 15.3 ± 4.7 mg% and 13.0 ± 8.0 mg%, respectively. Plasma triglyceride levels did not correlate with the length of the period after liver transplantation. Levels of LDL-C and total HDL-C and the relative weight composition of VLDL, LDL, HDL₂, and HDL₃ particles did not differ between post-liver transplantation children and controls. Posttransplantation, levels of HDL_3, the normally predominant HDL subfraction, were decreased relative to HDL₂levels (HDL₃, 1.3; HDL₂, 2.3). Because this observed relative increase in larger cholesteryl ester-rich HDL particles (HDL₂) may result from inhibition of cholesteryl ester-triglyceride transfer processes, cholesteryl ester transfer protein activity was assayed. Cholesteryl ester transfer protein activity did not differ between patients and controls. Thus, the lipoprotein changes observed in children post-liver transplantation are mild hypertriglyceridemia and a significant increase in HDL₂relative to HDL₃. Because HDL₂ is regarded as protective against atherosclerosis, this may be of clinical relevance.