[Hypoalphacholesterolemia: dynamics of the subfractional spectrum of high density lipoproteins during their interaction with fibroblasts and hepatoma Hep-G2 cell line].

Using gradient gel electrophoresis, the dynamics of subfractional spectrum of high density lipoproteins (HDL) according to the particle size was studied during HDL interaction with hepatoma Hep-G2 cells and human skin fibroblasts. It was found that incubation of sera obtained from normolipidemic donors with cholesterol-loaded fibroblasts results in a decrease of the proportion of all small-sized particles of the HDL3 subclass, i.e., HDL3a, HDL3b and HDL3c as well as in an increase in the proportion of large-sized particles of the HDL2 subclass (HDL2a and HDL2b) due to cholesterol acceptance by HDL. In contrast, incubation of the same sera with hepatoma Hep-G2 cells causes a decrease in the proportion of HDL2b and a release of smaller cholesterol-deficient HDL3a particles. The dynamics of subfractional spectrum of HDL in hypoalphacholesterolemic sera is somewhat different, i.e., incubation with fibroblasts results in a decrease of the proportion of HDL3b and HDL3c; that of HDL2a is increased. The HDL2b fraction is unchanged. After incubation of the same sera with hepatoma Hep-G2 cells, the proportion of HDL2b does not fall as in the case of normolipidemic sera, but shows a marked increase. It is concluded that hypoalphacholesterolemia is characterized not only by a low HDL level in the plasma, but also by the formation of HDL2b-deficient particles which less effectively interact with liver cells.