Influence of variation at the apolipoprotein E locus on lipid and lipoprotein levels in CAPD patients

Background. Variation at the apolipoprotein E (apo E) locus influence lipid and lipoprotein levels in the normal population, and is associated with premature coronary artery disease. Patients with end-stage kidney disease or undergoing dialysis treatment are particularly prone to develop accelerated atherosclerosis. Methods. To evaluate the influence of genetic variation at the apo E locus, apo E genotypes and serum lipid and lipoprotein levels were measured in 51 subjects undergoing continuous ambulatory peritoneal dialysis (CAPD). Results. The distribution of apo E phenotypes and apo E allelic frequency among the CAPD subjects (ε2 0.049; ε3 0.745; ε4 0.206) corresponded to the healthy Swedish population. In the CAPD subjects, total serum and LDL cholesterol levels were high (6.7 ± 1.5 mmol/l and 4.2 ± 1.3 mmol/l respectively) and HDL cholesterol levels were low (1.2 ± 0.5 mmol/l). When directly comparing the two major apo E groups, E 3/3 subjects (n = 30) and E4/3 and 4/4 subjects, ε4-carriers, (n = 16), LDL cholesterol levels were significantly higher among ε4-carriers (4.8 ± 1.1 vs 4.0 ± 1.2 mmol/l, P < 0.03), but total serum cholesterol levels was not higher among the ε4-carriers (7.3 ± 1.3 vs 6.5 ± 1.5 mmol/l, P < 0.08). Serum triglycerides or HDL cholesterol levels did not differ significantly between ε3-homozygotes and ε4-carriers. Conclusions. The results demonstrate a strong effect of variation of the apo E locus on LDL cholesterol levels in CAPD subjects, suggesting that ε4-carriers may be more susceptible to accelerated development of atherosclerosis in this condition.