Abnormal particle size of lipoprotein in non-insulin-dependent diabetics and nondiabetics with and without hyperlipidemia.

To clarify the mechanism of the high incidence of ischemic heart disease in the diabetics, we studied the particle size of the lipoprotein with particular attention to the structural abnormality. Using high performance liquid chromatography, the particle size of the lipoprotein was determined with elution volume, which was precisely correlated with the particle size. The particle size of low density lipoprotein (LDL) from the diabetics with normolipidemia is larger than that from the nondiabetics (p less than 0.001) in the elution pattern of triglyceride. The examination of the elution pattern of the triglyceride and cholesterol revealed that this large LDL was composed of a large amount of triglyceride. These characteristics of the large LDL resembled that of the atherogenic intermediate density lipoprotein. The particle size of high density lipoprotein (HDL) from the diabetics with normolipidemia was larger than that from the nondiabetic controls (p less than 0.001), detected by the elution pattern of triglyceride. The comparison of the triglyceride and cholesterol elution pattern indicated that also the large HDL in the diabetics with normolipidemia was rich with triglyceride, which was reported to inhibit the activity of the lipid transfer protein. These facts revealed that the disorder of the lipid metabolism not accompanied with hyperlipidemia produced the large LDL and HDL, which might lead to the excess mortality rate of the ischemic heart disease in the diabetics even with normolipidemia.