Low-density lipoprotein subfraction profiles in chronic renal failure

Background. Small low-density lipoprotein (LDL) particle size, a newly recognized risk factor for cardiovascular disease in the general population, is frequently associated with hypertriglyceridaemia, the predominant plasma lipid abnormality present in uraemia. Methods. Plasma lipids and LDL subfraction profiles were examined in 33 non-dialysed patients with chronic renal failure (predial), 40 patients on continuous ambulatory peritoneal dialysis (CAPD), 42 haemodialysis patients (HD), 47 renal transplant recipients (RTR), and 44 controls. LDL subfractions separated by gel electrophoresis were scored by densitometric analysis (higher scores indicate profiles comprising smaller particles). Results. All groups with renal failure had significantly elevated (mean +/- SD) LDL scores (predial 1.36 +/- 0.6, CAPD 1.71 +/- 0.9, HD 1.68 +/- 0.9, RTR 1.92 +/- 0.8 vs control 0.87 +/- 0.4, all P < 0.001), this being the only lipid abnormality detected in the predialysis patients. In CAPD and HD patients, LDL scores were associated with serum triglyceride (r = 0.81, P < 0.001 and r = 0.70, P < 0.001 respectively), cholesterol (r = 0.55, P < 0.001 and r = 0.49, P < 0.01) and HDL-cholesterol (r = -0.43, P < 0.01 and r = -0.51, P < 0.01), whilst no such relationship was seen in the predialysis and RTR groups, suggesting that other factors were important. Conclusions. The presence of small LDL particles appears to be an early and unexplained feature of the uraemic dyslipidaemia. This abnormality persists after renal transplantation and may represent an important atherogenic risk factor.