Distinct patterns of heparin affinity chromatography VLDL1 and VLDL2 subfractions in the different dyslipidaemias

Very low density lipoprotein (VLDL) 1 and 2 were fractionated by heparin affinity chromatography into a bound and an unbound fraction and the different subfractions were quantified in 17 normolipidaemic (NL), 13 hypercholesterolaemic (HC), 10 hypertriglyceridaemic (HTG) and 11 combined hyperlipidaemic subjects (CHL). Unbound VLDL1 and VLDL2 were, respectively, 1.9- and 2.2-fold richer in triglycerides than bound VLDL1 and VLDL2. In HTG and CHL the concentration of all the VLDL subfractions was increased and plasma triglyceride level was correlated to unbound VLDL1 and to bound VLDL1 (respectively, r=0.86 (p<0.001) and r=0.77 (p<0.01) in HTG and r=0.73 (p<0.001) and r=0.62 (p<0.05) in CHL). In HC unbound VLDL2 and bound VLDL2 concentration were increased compared to NL and in CHL, the concentration of bound VLDL2 was particularly increased (3.2-fold compared to NL (p<0.001)). In both HC and CHL bound VLDL2 concentration was correlated to low density lipoprotein cholesterol (LDL-C) concentration (respectively, r=0.67 (p<0.01) and r=0.62 (p<0.05)). In hypertriglyceridaemic states the intravascular accumulation of both unbound and bound VLDL1 appears as the determinant of plasma triglyceride concentration, whereas in moderately hypercholesterolaemic states the concentration of bound VLDL2 is strikingly correlated to LDL-C concentration, suggesting that these two species are linked metabolically, e.g. bound VLDL2 contain the precursor pool of LDL.