Use of Cell Transit Analyser pulse height to study the deformation of erythrocytes in microchannels.

Information on microvascular rheology can be used to develop mathematical models of network hemodynamics in various contexts: tumor-induced angiogenesis, reaction to ischemia and collateralization, hypertension, ... The rheological method which probably most closely simulates red blood cell (RBC) flow behavior in the microcirculation is the determination of individual erythrocyte transit time and shape changes during flow through cylindrical micropores. However, these filtration experiments remain difficult to interpret in terms of cell flow properties, because the shape of the cell inside the pore is unknown. This paper uses the cell transit analyser (CTA) electrical pulse (especially the pulse height) to determine the relationship between the cell velocity and deformed shape in the pore, depending on the flow strength, suspending medium viscosity and cell membrane elasticity. As predicted by published numerical simulations for the flow of deformable particles through narrow channels, increasing pressure leads to increased deformation, but for a given pressure, increased viscosity leads to a slight increase in deformation. The sensitivity of filtration experiments to cell mechanical properties is improved when using low driving pressures and narrow and sufficiently long pores.