Effect of statil (ICI 128436) on erythrocyte viscosity in vitro

The hypothesis that sorbitol accumulation could contribute to a reduced erythrocyte deformability in diabetes was investigated. Erythrocyte sorbitol and erythrocyte viscosity at high and low shear rates were studied in 20 insulin-dependent diabetic (IDDM) and 20 matched control subjects. An increased erythrocyte sorbitol and an increased low-shear erythrocyte viscosity were found in the IDDM patients, but there was no significant correlation (r = .11, NS) between the parameters. Incubation (3 h, 37 degrees C) in a Krebs buffer containing 33.3 mM glucose resulted in a significant sorbitol accumulation, but erythrocyte viscosity was not affected. Despite this fact, addition of 1 mM statil (ICI 128436) in the 5.5- and 33.3-mM glucose media not only prevented erythrocyte sorbitol accumulation but also improved erythrocyte viscosity in diabetic and control subjects. The effect was more pronounced at the low (approximately 16%) than at the high (approximately 2%) shear rate. The effect on erythrocyte viscosity disappeared by washing the erythrocytes after incubation, although erythrocyte sorbitol remained different. Our results suggest that sorbitol accumulation does not contribute to an increased erythrocyte viscosity in diabetes, and statil shows a positive effect on erythrocyte viscosity independent of its aldose reductase-inhibiting property.