Influence of intracellular convection on the oxygen release by human erythrocytes.

Abstract

There is general agreement today that intracellular diffusive transport of HbO2 and O2 limits the rate of oxygen uptake or release by the blood in the exchange vessels. Recent hemorheological results have shown that the mammalian erythrocyte exhibits fluidity as its most unique rheological property: it can be deformed continuously and rapidly, shear and normal stresses can be transmitted to the interior of the cell where systems of laminar flow are induced. These mechanical properties lead to the question whether or not intracellular convection does take place in the erythrocyte and to what extent it plays a part in gas exchange. A method was developed which subjects oxygen-saturated solutions and cell suspensions to an artificial but well defined flow (cone-plate-viscosimeter), and allows simulataneous determination of the initial O2 release indices under standardized conditions (O2 saturation, temperature, time, diffusion area, and difference of O2 partial pressure). The results strongly suggest that intracellular flow resulting from the physiological erythrocyte deformation in flow can supplement the O2 release from intact cells through a convective transport of HbO2 and O2 molecules. The example of osmotic shrinking shows that red cell fluidity is not only a precondition for normal flow in the microcirculation, but also for the normal gas exchange of the cells.