A synthetic polycation, a copolymer of 1-vinyl-3-methylimidazole iodide with maleic acid diethyl ester, increases passive ionic permeability in erythrocyte membranes modified by fatty acids.

The effect of the synthetic polycation VMII-DEMA (a potential antiheparin agent) on the ion transport through erythrocyte membranes was studied using ion-selective electrodes. We found that the passive ionic permeability of erythrocyte membranes in the presence of VMII-DEMA noticeably increased after the pretreatment of erythrocytes with long-chain fatty acids. When used separately, neither polycation nor fatty acids changed the membrane permeability at the same concentrations. The efficiency of the combined action of the polycation and fatty acids correlated with the length of the fatty acid (C9-C18) and the number of double bonds in it. The fatty acids C12:0, C13:0 and C18:2 were the most efficient. We suggest that in pathologies accompanied with deteriorations in lipid metabolism, polycations used for the correction of blood coagulation may damage the erythrocyte membrane.