Morphological changes of human erythrocytes induced by cholesterol sulphate

Morphological alterations of human erythrocytes induced by cholesterol sulphate (5-cholesten-3 beta-ol sulphate, CS) were studied.

Influence of CS on red blood cell stability (in isotonic conditions) by simultaneous application of flow cytometry and scanning electron microscopy was studied.

In isotonic medium CS induces erythrocyte size and shape changes in dose-and time-dependent manner. Incubation (in vitro) of erythrocytes with CS concentrations from 4 x 10(-5) mol/dm3 to 8 x 10(-5) mol/dm3 led to a progressive sphero-echinocitic shape transformation accompanied by a cell size decrease. In contrast to this, for CS content equal to 1 x 10(-5) mol/dm3 the maintenance of the normal biconcave shape of red blood cells was observed.

The results suggest that CS, similarly to numerous evaginating amphiphilic agents, induces a transformation of the erythrocyte normal discoid shape to echinocytic form. This effect may be caused, at least partly, by an asymmetric expansion of the membrane lipid bilayer due to asymmetric distribution of CS incorporated into the membrane. The echinocytic shape transformation of erythrocytes indicated that CS intercalates in the outer hemileaflet of the lipid bilayer leading to membrane externalization.