The Clinical Significance of Apolipoprotein E Polymorphism in Patients with Non-Insulin-Dependent Diabetes Mellitus

Tazue Hoshino

First Department of Internal Medicine, Faculty of Medicine, Tottori University, Yonago 683, Japan

To investigate the clinical significance of apolipoprotein E (apoE) polymorphism in patients with non-insulin-dependent diabetes mellitus (NIDDM), apoE phenotypes were examined in 112 NIDDM patients. The patients were divided into 3 groups of E2 (E2/2 and E2/3), E3 (E3/3) and E4 (E3/4 and E4/4). The serum low-density lipoprotein cholesterol (LDL-C) and the ratio of apolipoprotein B (apoB) to apolipoprotein AI in the E4 group (181 ± 51 mg/dL and 1.4 ± 0.9) were significantly (P < 0.05) higher than in the E2 group (146 ± 43 mg/dL and 1.0 ± 0.4) and E3 group (149 ± 45 mg/dL and 1.0 ± 0.3), respectively. No differences were found in the levels of total cholesterol (TG), high-density lipoprotein cholesterol, triglyceride (TG) or apolipoproteins AI, AII, B, CII, CIII or E. There were no significant differences in the prevalence of retinopathy or nephropathy among groups. The prevalence of macroangiopathy (coronary heart disease and cerebral infarction) tended to be higher, but not significantly, in the E4 group than in the E2 or E3 group. In 37 hypercholesterolemic patients who were treated with pravastatin (10 mg/day) for 6 months, serum levels of TC, LDL-C and TG similarly decreased in spite of apoE phenotype, but the reduction of apoB was significantly (P < 0.05) lower in the E4 group (14.0 ± 15.0%) than in the E2 group (32.0 ± 11.4%) and E3 group (35.0 ± 16.3%), respectively. It was concluded that NIDDM patients with apoE4 tended to show marked abnormalities of lipid metabolism and to show less response to pravastatin compared to those with apoE2 and apoE3.

Key words: apolipoprotein E phenotype; diabetic microangiopathy; non-insulin-dependent diabetes mellitus

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