Pathological Analysis of Hyperlipidemia by a Newly Developed Agarose Electrophoresis

Abstract

An improved electrophoretic system for serum lipoproteins has been developed by Helena Laboratories lnc., Japan. Two serum samples, one for cholesterol analysis and the other for triglyceride (TG) analysis, were spotted on agarose gel. After electrophoresis, each lane was visualized with a specific dye for cholesterol or TG. Densitometric patterns ob tained from cholesterol and TG lanes were superimposed using a computer. In this study, serum samples from patients with types Ha, IIb and IV hyperlipidemia classified according to the lipoprotein pattern type as proposed by WHO were applied to the present system. A marked shift in the position of the low density lipoprotein-cholesterol (LDL-C) peak was observed in patients with types IIb and IV hyperlipidemia compared with that of normal subjects. The LDL-C peak positions of these two types of patients were normalized after the patients took anti-hyperlipidemic agents such as atorvastatin or pravastatin. To quantify the above LDL-C peak shift from the normal position, the LDL charge modification frequency was automatically calculated by this system. The correlation between LDL charge modification frequency and cholesterol or TG concentration in each lipoprotein fraction was determined in types IIa, IIb and IV hyperlipidemic patients. There was no correlation between LDL charge modification frequency and the overall lipid level observed in type IIa hyperlipidemic patients. In patients with type IIb hyperlipidemia, a significant correlation between LDL charge modification frequency and LDL-TG concentration was observed (γ=0.495, p<0.01). A significant correlation between LDL charge modification frequency and high density lipoprotein-cholesterol (γ=0.449, p<0.01), very low density lipoprotein (VLDL)-cholesterol (γ=0.753, p< 0.001), VLDL-TG (γ=0.655, p<0.001) and LDL-TG (γ=0.403, p<0.05) was observed in type IV hyperlipidemic patients. These findings suggest that the present electrophoretic system can provide useful information regarding lipid metabolism.