Influence of various sizes phospholipid particles for phospholipids and apoprotein A1 levels in high density lipoproteins subfractions after incubation with blood plasma in vitro

Abstract

Objective. The ability of high density lipoproteids (HDL) for cell cholesterol efflux was shown in recent years to depend not only from their concentration, but also from their properties, that are often disturbed in atherosclerosis by as yet unclear mechanisms. One of the ways of HDL cholesterol accepting increase is thought their enrichment by  phospholipids (PL). Here the influence of plasma incubation with earlier elaborated emulsion of PL particles with diameter 30 nm for HDL subfractions was studied, with comparison of effects of larger liposomes.
Methods. PL particles emulsion, prepared by earlier elaborated procedure from soy been phosphatidylcholine, and liposomes 100–150 nm were incubated with human plasma. HDL3 and remaining delipoproteidized plasma were isolated by ultracentrifugation and their PL and apoprotein A1 (apo A1) levels were determined.
Results. All HDL subfractions appeared to be phospholipidated, with more pronounced after incubation with ultrasmall, 30 nm PL nanoparticles. Maximal changes of both PL and apo A1 were in HDL2 – middle 3–6 fold increase. Changes in HDL3 and remaining plasma were in the range 30–50%. In contrast with PL, apo A1 level decreased, proportional with concentration of added PL nanoparticles. It was first shown the opposite character of apo A1 level as compared with other fractions after PL influence. Such redistribution of protein may be explained by decrease of particles densities with their sizes increase, that was supported by plasma agarose gel electrophoresis. Ratio PL/apo A1, that is considered to be important for cholesterol accepting activity, increased in all HDL sufractions, particularly after ultrasmall nanoparticles – two fold.
Conclusion. Incubation of plasma with PL particles less 30 nm results in high degree of phospholipidation of HDL2, HDL3 and remaining plasma, that have, as it was shown in a number of works, to stimulate cell cholesterol accepting activity. The results testify on prospectivity of such nanosystems usage in complex therapy of heart vessels diseases – for the goal of elevation of HDL activity and reverse cholesterol transport and for inhibition of atherosclerosis progression.