Alterations to complex viscoelasticity of erythrocytes during storage

Rheological alterations produced during the storage of human erythrocytes w ere studied by means of in vitro viscoelastic parameters. Weekly aliquots o f packed red blood cells (PRBC) and whole blood (WB) stored in CPD-adenine were studied for 35 days. Samples were analyzed in Erythrodeformeter both i n stationary and oscillating regime. We found that erythrocyte deformabilit y index and all complex viscoelastic parameters are modified by storage. Pl asma viscosity and blood viscosity were measured in a cone/plate Viscometer . Blood viscosity at high shear rates shows variations related to conservat ion time, which are in correlation with the variations observed in the eryt hrocyte deformability index. Blood viscosity at low shear rate decreases du ring storage. Rheological tests would demonstrate some alterations in the s tructural properties of erythrocyte stored as PRBC. These alterations are l ess than those found in WB. We conclude that plasmatic proteins play a pred ominant role in the alteration of rheological behavior of erythrocytes duri ng their storage. Consequently, it is important to evaluate not only cellul ar components but also plasma.