The Lipoprotein Fraction between VLDL and LDL Detected by Biphasic Agarose Gel Electrophoresis Reflects Serum Remnant Lipoprotein and Lp(a) Concentrations

Abstract

We analyzed lipoprotein profiles in 616 Japanese by biphasic agarose gel electrophoresis using Chol/Trig Combo^TM to yield HDL, VLDL, LDL and CM fractions which were stained with cholesterol and triglyceride reagents, respectively. To further evalute the pattern of electrophoresis, we analyzed the fraction between VLDL and LDL to confirm the possibility of a MidBand by using an automatic-five-fraction function. The cholesterol concentrations in MidBand (MidBand-C) showed a good correlation to remnant-like particle-cholesterol (RLP-C) (r = 0.95) in 23 consecutive samples (TC < 220 mg/dl, Lp(a) < 30 mg/dl). However, MidBand-C concentrations of subjects with high Lp(a) levels (Lp(a) > 30 mg/dl) were also high compared to RLP-C concentrations. The average MidBand-C levels in elderly normolipidemic control subjects (TC < 220, TG < 150) were 5.2 ± 2.4 mg/dl in 30 males (mean age, 70 ± 10 years) and 5.4 ± 2.0 mg/dl in 40 females (64 ± 11 years). The average MidBand-C levels of normolipidemic patients with coronary artery diseases (CAD; TC < 220, TG < 150) were 9.4 ± 4.1 mg/dl in 126 males (mean age, 66 ± 10 years) and 9.1 ± 4.0 mg/dl in 44 females (67 ± 10 years). These levels were significantly higher than control values (p < 0.0001). Areas under ROC curves were greater for MidBand-C than for TC, LDL-C and TG when used to discriminate between the patients with CAD and normolipidemic control subjects for each sex. There results suggest that the MidBand-C level may be useful as an indicator of risk for CAD.