Polymicroviscometry of spectrin cross-linked red blood cells: Theoretical and clinical implications

Abstract

Rheological investigation with the newly developed microcomputer-assisted automatic filtrometer (polymicroviscometer) allows the analysis of the flow behaviour of packed red blood cells. Based on a filtration approach different from the ‘microsieving’ of blood, the polymicroviscometry is assessing the ability of red cells to participate in flow by ‘tanktreading’ of their membrane, which corresponds to the viscous component of their rheological behaviour.

Treatment of normal red cells with diamide results in spectrin cross-linking. Although such experimentally modified cells have a membrane with an increased modulus of shear elasticity, they present most remarkably an almost normal flow behaviour in the polymicroviscometer. Data obtained in the polymicroviscometer correlate well with results of experimental investigation of the microcirculation in-vivo performed with such modified cells.

It is concluded that information obtained with different methods to assess the red cell ‘deformability’ are not reflecting the same features of mechanical behaviour. Moreover, it is suggested that the shear elasticity of the membrane might not have the physiological and pathophysiological importance it has long been attributed with.

Key Words:

• elasticity
• red cell membrane
• filterability
• redcells
• filtrometer
• flow behaviour
• flow equation
• microcomputer-assisted polymicroviscometry
• polymicroviscometry
• spectrin
• cross-linking