ABSTRACT
The quantitative analysis of sub-fractions of lipoproteins acquires growing significance in diagnostic and prognosis of cardiovascular diseases. It is well known that presence of lipoprotein (a) in high concentrations significantly distorts results of biochemical analysis, in particular detection of level of cholesterol of low-density lipoproteins. The lipoprotein (a) is a heterogeneous particle and its mobility in the systems used for analysis of sub-fractions of lipoproteins can have significant variability that will bring inaccuracy into results. The data concerning relationship between lipoprotein (a) and sub-fractions of lipoproteins and also their differentiation in various systems of determination of lipid spectrum are quite numerous. The given study is considered as actual one because it analyses input of lipoprotein (a) into results of detection of sub-fractions using the technique with diagnostic significance. The study was carried out for evaluating possible input of lipoprotein (a) into results of quantitative estimation of sub-fractions of lipoproteins by technique of native electrophoresis in polyacrylamide gel used for diagnostic of cardio-vascular diseases. To detect concentration of lipoprotein (a) in blood serum the technique of enzyme-linked immunosorbent assay was applied. The qualitative valuation of content of sub-fractions of lipoproteins was implemented using system Lipoprint Quantimetrix (USA). The sub-fractions of lipoproteins were detected in samples of serum of healthy donor and normolipidic patients before and after removal of lipoprotein (a) using technique of affine chromatography in vitro. It turned out that after removal of lipoprotein (a) analysis of sub-fractions of lipoproteins in plasma of healthy donor detects significant decreasing of level of lipoproteins of medium density. The samples of serum of patients with atherosclerosis besides removal of sub-fractions of lipoproteins of medium density, decreasing of level of large sub-fractions of low density lipoproteins was observed. The analysis of samples obtained after procedures of therapeutic lipoprotein (a) apheresis using columns "Lp (a) Lipopak" (Russia) demonstrated that along with removal of lipoprotein (a), decreasing of concentration of sub-fraction C lipoproteins of medium density in all samples that substantiates in vitro data. In patients without affection and with multi-vessel lesion of coronary bloodstream reliable differences in concentration of lipoproteins of medium density were established. The received data testify that high level of lipoprotein (a) can contribute significant inaccuracies into results of detection of subfractions of lipoproteins. Therefore, application of system Lipoprint (Quantimetrix USA) provides no opportunity to unequivocally interpret data concerning input of sub-fractions of lipoproteins into risk of development of cardio-vascular diseases in patients with pathological lipid profile and higher concentration of lipoprotein (a).
