Effect of osmolality on erythrocyte rheology and perfusion of an artificial microvascular network



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Microvascular Research


Plasma sodium concentration is normally held within a narrow range. It may, however, vary greatly under pathophysiological conditions. Changes in osmolality lead to either swelling or shrinkage of red blood cells (RBCs). Here we investigated the influence of suspension osmolality on biophysical properties of RBCs and their ability to perfuse an artificial microvascular network (AMVN). Blood was drawn from healthy volunteers. RBC deformability was measured by osmotic gradient ektacytometry over a continuous range of osmolalities. Packed RBCs were suspended in NaCl solutions (0.45, 0.6, 0.9, 1.2, and 1.5 g/dL), resulting in supernatant osmolalities of 179±4, 213±1, 283±2, 354±3, and 423±5 mOsm/kg H2O. MCV (mean corpuscular volume) and MCHC (mean corpuscular hemoglobin concentration), were determined using centrifuged microhematocrit. RBC suspensions at constant cell numbers were used to measure viscosity at shear rates ranging from 0.11 to 69.5 s?1 and the perfusion rate of the AMVN. MCV was inversely and MCHC directly proportional to osmolality. RBC deformability was maximized at isosmotic conditions (290 mOsm/kg H2O) and markedly decreased by either hypo- or hyperosmolality. The optimum osmolality for RBC suspension viscosity was shifted towards hyperosmolality, while lower osmolalities increased suspension viscosity exponentially. However, the AMVN perfusion rate was maximized at 290 mOsm/kg H2O, and changed by less than 10% over a wide range of osmolalities. These findings contribute to the basic understanding of blood flow in health and disease, and may have significant implications for the management of osmotic homeostasis in clinical practice.



osmolality, red blood cell deformability, microvascular perfusion, microfluidics


Copyright 2015 Microvascular Research. This is a post-print version of a published paper that is available at: https://www.sciencedirect.com/science/article/pii/S0026286215000114 Recommended citation: Reinhart, W. H., N. Z. Piety, J. S. Goede, and S. S. Shevkoplyas. "Effect of osmolality on erythrocyte rheology and perfusion of an artificial microvascular network." Microvascular research 98 (2015): 102-107. DOI: 10.1016/j.mvr.2015.01.010 This item has been deposited in accordance with publisher copyright and licensing terms and with the author’s permission.