Apolipoprotein E2, renal failure and lipid abnormalities in non-insulin-dependent diabetes mellitus

The association of apolipoprotein E (apo E) genetic polymorphism, particularly apo E2, with renal failure (plasma creatinine > or = 1.4 mg/dl, and urinary albumin excretion index > or = 300 mg/g.creatinine and/or persistent proteinuria) was investigated in 57 non-insulin-dependent diabetic (NIDDM) patients. Apo E2 allele frequency was significantly higher in diabetic patients with renal failure (9.6%) than in diabetic patients without renal failure (3.2%) and in the general Japanese population (3.7%). This finding suggests that apo E2 is associated with renal failure in NIDDM. In addition, to elucidate the association of apo E2 with lipid abnormalities, plasma lipid and lipoprotein levels were compared among the apo E2 (E2/2 and E3/2) and E3/3 groups of NIDDM with renal failure (n = 27) and the apo E2 (E3/2) and E3/3 groups of NIDDM with normoalbuminuria (n = 34). In diabetic patients, the apo E2 group with renal failure had significantly higher levels of plasma total cholesterol (T-chol), very-low-density lipoprotein (VLDL)-chol, triglyceride (TG), VLDL-TG and apo E than the apo E3/3 group with renal failure, and had significantly higher levels of plasma T-chol, VLDL-chol, TG and VLDL-TG than the apo E2 and E3/3 groups with normoalbuminuria. Furthermore, the apo E2 group with renal failure had significantly higher ratios of VLDL-(chol/TG) and VLDL-chol/TG (an index of remnants in plasma) than the apo E3/3 group with renal failure and the apo E2 and E3/3 groups with normoalbuminuria. These results suggest that apo E2 leads to the accumulation of TG-rich lipoprotein and remnants in plasma. It is concluded that apo E2 is associated with renal insufficiency in NIDDM and that apo E2 may be a factor that aggravates lipid abnormalities in NIDDM with renal failure.