ApoE-2/E-3 ratio of very low density lipoprotein in diabetes mellitus.

Apolipoprotein E (apoE) of very low density lipoprotein (VLDL) in 22 diabetic patients was analysed by the method of one-dimensional isoelectrofocussing (IEF). We modified the IEF-method of Kashyap et al. by which apoE isoproteins were easily and accurately determined. The measurement of apoE-2/E-3 ratio was useful for determining apoE phenotypes. In 17 of 22 diabetics apoE phenotype was E3/3, while three patients showed E2/3 and two showed E3/4. ApoE-2/E-3 ratio was reduced from 0.91 +/- 0.07 to 0.73 +/- 0.04 (p less than 0.05) by the one month-period treatment in 10 insulin required diabetics. The ratio was also reduced from 1.06 +/- 0.14 to 0.89 +/- 0.09 (p less than 0.2) in 10 non-insulin required diabetics. The reduction in apoE-2/E-3 ratio was caused by an increase in apoE-3 band and a decrease in apoE-2 band which might be attributed to the changes in the sialic acid-content of isoproteins on the one-dimensional IEF method. Therefore, apoE phenotypes in diabetic patients should be determined when their diabetic state is improved.