Low density lipoprotein particle size phenotyping in healthy persons and patients with myocardial infarction

Aim. To determine distribution, size, and phenotype of low density lipoprotein (LDL) subclasses and examine the influence of plasma lipid concentrations on lipoprotein particle size in both healthy population and patients with myocardial infarction. Methods. Nondenaturing gradient (3-31 %) gel electrophoresis for lipoprotein separation was used to determine the distribution and size of LDL subclasses in 132 patients with myocardial infarction and 334 healthy control Subjects. Results. Large LDL subclasses (LDL1, LDL2, phenotype A) were dominant in 88.5% of the healthy population, whereas in most patients with myocardial infarction (81 %) the dominant subclasses were LDL3 and LDL4 (phenotype B). Only 19% of the patients belonged to the phenotype A (LDL1 and LDL2). Mean LDL subclass size (nm) was significantly smaller in patients with myocardial infarction than in controls (24.38 +/- 1.07 nm vs 25.94 +/- 0.89 nm; p < 0.001). In both groups, LDL size was independent of LDL plasma cholesterol but associated with high triglyceride plasma concentrations. Conclusion. Coronary artery disease is associated with the predominance of small LDL particles and high plasma triglyceride concentrations. The risk of development of cardiovascular disease can be assessed more accurately by determining lipoprotein subclasses.