THE RATIO OF LOW-DENSITY LIPOPROTEIN CHOLESTEROL TO APOLIPOPROTEIN-B AS A MARKER OF LOW-DENSITY LIPOPROTEIN PARTICLE SIZE

Abstract

The aim of this study was to determine the informative value and clinical significance of the ratio of low-density lipoprotein cholesterol to apolipoprotein-B (LDL-C/apoB) in the overall evaluation of blood lipid profile atherogenicity. Material and methods. A total of 157 apparently healthy men with normolipidemia were included in the study. The plasma levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), apoA-I, apoB and apoE were measured on the Powerwave 200 automated spectrophotometer (USA) with commercially available kits (Chronolab Systems, Spain). Several clinical ratios and indices of lipid metabolism were calculated. Results. The use of apoB content in low-density lipoproteins (LDL) instead of total apoB level in plasma is preferable in calculating the LDL-C/apoB ratio. Low values of the LDL-C/LDL-apoB ratio, indicating a predominance of small dense LDL particles in plasma, were associated with higher triglycerides levels and lower apoE levels. This finding indicates that apoE, being a metabolically active apolipoprotein and regulating residence of triglycerides-rich lipoproteins in plasma, can affect size of the LDL particles. Conclusion. Thus, presence of small, dense LDL particles in plasma of men with normolipidemia can be a consequence of disturbances in catabolism and metabolic turnover of lipoproteins.