Gradient gel electrophoretic separation of LDL and HDL subclasses on BioRad Mini Protean II and size phenotyping in healthy Macedonians

Background: Lipoprotein subclass determinations provide a more detailed reflection of lipoprotein metabolism and an accurate prediction for risk of cardiovascular disease. Gradient gel electrophoresis for lipoprotein separation on Pharmacia electrophoretic apparatus has been most commonly used for many years. Methods: In this paper, we describe a new method for separating LDL and HDL subclasses by nondenaturing polyacrylamide gradient (3-31%) gel electrophoresis, using BioRad Mini Protean U electrophoretic cells. Results: The mean particle diameters of cholesterol-stained LDL and HDL lipoproteins were estimated after calibrating the gels with size standards, using fractional absorbance profiles. For the first time in the Republic of Macedonia, lipoprotein distribution and size phenotyping were studied in 345 healthy individuals. Large LDL subclasses (phenotype A) were dominant in 88.5% of the population, whereas small LDL subclasses (phenotype B) were dominant in 11.5%. The mean dominant LDL size was 26.08 +/- 0.8 nm. Five HDL subclasses were separated on the same gels, and HDL2b and HDL2a (larger) were dominant in healthy Macedonians. Conclusion: Anti atherogenic, larger LDL and HDL particles are most commonly found in healthy populations in the Republic of Macedonia. (C) 2002 Elsevier Science B.V. All rights reserved.