Apolipoprotein E phenotypes in hemodialysis patients

Apolipoprotein (apo) E polymorphism consists of three major isoproteins (E2, E3, and E4). Because of their difference in a lipid-modulating effect, the polymorphism has been reported to affect the morbidity of atherosclerosis in general population. Therefore, in hemodialysis (HD) patients, the apo E polymorphism may also modulate serum levels of cholesterol and susceptibility to atherosclerotic vascular disease.

We determined apo E phenotypes in 493 HD patients and 422 controls. We also investigated vascular risk profile and measured postprandial serum levels of lipids and apos in the dialysis patients.

We found a similar phenotype distribution and allele frequency between HD patients and healthy controls. Serum levels of total cholesterol, triglyceride, and apo A I, A II, and C III did not differ significantly among patients with phenotypes apo E2/3, E3/3, and E3/4. Patients with apo E3/4 had significantly lower levels of high-density lipoprotein cholesterol, significantly higher levels of low-density lipoprotein cholesterol (LDL-C), and a higher atherogenic index than those with apo E2/3 (LDL-C, 100 +/- 30 vs. 82 +/- 35 mg/dl, P < 0.01; the index, 3.3 +/- 1.7 vs. 2.3 +/- 1.3, P < 0.01). Patients with apo E3/4 showed a tendency toward higher levels of apo B than patients with apo E2/3 or apo E3/3. Multiple logistic regression analysis revealed that age and diabetes mellitus, but not apo E phenotypes, were independent risk factors for vascular disease.

Apo E polymorphism modulates cholesterol metabolism in dialysis patients but appears to have little association with the prevalence of atherosclerotic complications in the patients.