Apolipoprotein E polymorphism in diabetic and non-diabetic patients: does it really contribute to atherosclerosis?

Objective: The exact mechanism of the increased cardiovascular morbidity and mortality in type-2 diabetes is still undefined. The aim of our study was to assess the impact of apolipoprotein E (apo E) polymorphism and other factors on atherosclerotic vascular disease in type-2 diabetic patients. We also examined the association between apo E polymorphism and lipid profile in diabetic patients.

Methods And Results: We assessed the apo E polymorphism in 295 atherosclerotic patients (124 of them had diabetes (according to WHO criteria) and 171 of them had coronary artery narrowing > 50). The detection of apo E polymorphism was made by Real-Time PCR using a Light-Cycler (Roche diagnostics, GmbH, Mannheim, Germany). Serum triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), lipoprotein (a) [Lp(a)], apolipoprotein A (Apo A) and apolipoprotein B (Apo B) levels were determined by biochemical analyser. Genotypic distribution of apo E polymorphism did not differ between diabetic and non-diabetic atherosclerotic patients. The distributions of apo E2/2, E2/3, E2/4, E3/3, E3/4 and E4/4 genotypes in diabetic and non-diabetic atherosclerotic patients were 7.3%: 8.2%, 15.3%: 15.8%, 4.0%: 5.3%, 50.8%: 56.7%, 16.9%: 11.1% and 5.6%: 2.9%, respectively. Participants were grouped as apo E2 (E2/2 or E2/3), apo E3 (E3/3), or apo E4 (E4/4 or E4/3). The distributions of apo E2, E3 and E4 alleles were 23.5%, 52.9%, 23.5%, for diabetic patients, and 25.3%, 59.9%, 14.8% for non-diabetic patients, respectively. The apolipoprotein E genotype was not associated with the lipid levels in diabetic patients.

Conclusions: Our findings imply that apo E polymorphism is not related to the development of atherosclerosis in patients with type-2 diabetes.