Vesiculation induced by amphiphiles in erythrocytes

Abstract

The ability of shape-transforming cationic, anionic, zwitterionic, and nonionic amphiphiles to induce vesiculation in human erythrocytes was studied. At concentrations where they exhibit maximum protection against hypotonic haemolysis (CAHmax) echinocytogenic amphiphiles induced a rapid release of exovesicles. Following 5 min of incubation, the vesicle release (acetylcholinesterase release) amounted from 4% (sodium alkyl sulphates) to 13% (zwittergents) of the total acetylcholinesterase activity of the erythrocytes. At concentrations corresponding to CAH50 the vesicle release was less than 15% of that released at CAHmax. The size and the appearance of the vesicles varied with the type of amphiphile. Stomatocytogenic amphiphiles which do not pass the erythrocytes through echinocytic stages, did not induce release of exovesicles. Electron and fluorescence microscopic observations of erythrocytes treated with stomatocytogenic amphiphiles strongly indicated that an endovesiculation had occurred. Amphiphiles which pass the erythrocytes through echinocytic stages before stomatocytic shapes are attained, induced a release of both exo- and endovesicles.