Ifosfamide-induced stomatocytosis and mesna-induced echinocytosis: influence on biorheological properties of blood.

Ifosfamide is an alkylating agent which has poorly understood toxic side effects such as encephalopathy. We hypothesized that ifosfamide and concomitantly applied mesna could have an influence on the flow properties of blood, and thus carried out an in vitro study. Whole blood was incubated in vitro with increasing concentrations of ifosfamide (0-50 mg/ml), mesna (0-20 mg/ml) and combinations thereof. Chloroacetaldehyde, a major metabolite of ifosfamide, was also studied (0-5 mmol/l). Ifosfamide led to a dose-dependent stomatocytic shape transformation and mesna to an echinocytic shape transformation of erythrocytes. These shape changes were reversible upon removal of the causing agent. Both shape changes increased whole blood viscosity. Erythrocyte aggregation was decreased by both drugs at high concentration. Erythrocyte deformability, as measured with the transit time through 5-microm pores, was decreased by mesna and remained unaffected by ifosfamide. These effects were seen at concentrations which may be reached in vivo at the infusion site of the drugs into a vein and in the urinary tract. We conclude that ifosfamide and mesna interact with the lipid bilayer of the cell membrane, which may contribute to the toxicity of the compounds.