Investigation of low density lipoprotein subfractions as a coronary risk factor in normotriglyceridaemic men

There is an increasing interest in low density lipoprotein (LDL) subfractions since some of them are associated with a higher risk for coronary artery disease (CAD). Small LDL particles are particularly atherogenic and more of those are produced in hypertriglyceridaemia. However, high triglyceride concentrations are not the only explanation for the predominance of small LDL particles and other influences, including genetic factors, are also responsible for LDL particle size. We investigated LDL subfraction profiles in two groups: 46 men with and 21 men without CAD proven angiographically. For the separation of LDL subfractions, we used continuous disc polyacrylamide gel electrophoresis (PAGE) that is rapid and easier to perform than the other methods usually used which, although more precise in terms of measuring particle diameter, are much more demanding of time and equipment. The described method is suitable for routine use in assessing large numbers of patients. All studied men had triglyceride concentrations below 2.3 mmol/l. LDL scores were calculated on the basis of all LDL subfractions present in a particular profile; the higher the score, the greater the proportion of small LDL particles. LDL cholesterol (P < 0.05) and LDL score (P < 0.001) were the only significant discriminators between two groups. LDL score was significantly correlated with CAD, even after adjusting for triglyceride and HDL cholesterol concentrations and it was the best discriminant factor for the presence of CAD.