Browsing by Author "Abidi, Rajaa"
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Item Shape matters: the effect of red blood cell shape on perfusion of an artificial microvascular network(Transfusion, 4/1/2017) Piety, Nathaniel Z.; Reinhart, Walter H.; Pourreau, Patrick H.; Abidi, Rajaa; Shevkoplyas, Sergey S.BACKGROUND The shape of human red blood cells (RBCs) deteriorates progressively throughout hypothermic storage, with echinocytosis being the most prevalent pathway of this morphological lesion. As a result, each unit of stored blood contains a heterogeneous mixture of cells in various stages of echinocytosis and normal discocytes. Here we studied how the change in shape of RBCs following along the path of the echinocytic transformation affects perfusion of an artificial microvascular network (AMVN). STUDY DESIGN AND METHODS Blood samples were obtained from healthy consenting volunteers. RBCs were leukocyte-reduced, re-suspended in saline, and treated with various concentrations of sodium salicylate to induce shape changes approximating the stages of echinocytosis experienced by RBCs during hypothermic storage (e.g. discocyte, echinocyte I, echinocyte II, echinocyte III, sphero-echinocyte and spherocyte). The AMVN perfusion rate was measured for 40% hematocrit suspensions of RBCs with different shapes. RESULTS The AMVN perfusion rates for RBCs with discocyte and echinocyte I shapes were similar, but there was a statistically significant decline in the AMVN perfusion rate between RBCs with shapes approximating each subsequent stage of echinocytosis. The difference in AMVN perfusion between discocytes and spherocytes (the last stage of the echinocytic transformation) was 34%. CONCLUSION The change in shape of RBCs from normal discocytes progressively through various stages of echinocytosis to spherocytes produced a substantial decline in the ability of these cells to perfuse an artificial microvascular network. Echinocytosis induced by hypothermic storage could therefore be responsible for a similarly substantial impairment of deformability previously observed for stored RBCs.Item Washing stored red blood cells in an albumin solution improves their morphological and hemorheological properties(Transfusion, 8/1/2016) Reinhart, Walter H.; Piety, Nathaniel Z.; Deuel, JeremyW.; Makhro, Asya; Schulzki, Thomas; Bogdanov, Nikolay; Goede, Jeroen S.; Bogdanova, Anna; Abidi, Rajaa; Shevkoplyas, Sergey S.BACKGROUND Prolonged storage of red blood cells leads to storage lesions, which may impair clinical outcomes after transfusion. A hallmark of storage lesions is progressive echinocytic shape transformation, which can be partially reversed by washing in albumin solutions. Here we have investigated the impact of this shape recovery on biorheological parameters. METHODS Red blood cells stored hypothermically for 6–7 weeks were washed in a 1% human serum albumin solution. Red cell deformability was measured with osmotic gradient ektacytometry. The viscosity of red cell suspensions were measured with a Couette-type viscometer. The flow behaviour of red cells suspended at 40% hematocrit was tested with an artificial microvascular network. RESULTS Washing in 1% albumin reduced higher degrees of echinocytes and increased the frequency of discocytes, thereby shifting the morphological index towards discocytosis. Washing also reduced red cell swelling. This shape recovery was not seen after washing in saline, buffer or plasma. Red cell shape normalisation did not improve cell deformability measured by ektacytometry, but it tended to decrease suspension viscosities at low shear rates and improved the perfusion of an artificial microvascular network. CONCLUSIONS Washing of stored red blood cells in a 1% human serum albumin solution specifically reduces echinocytosis, and this shape recovery has a beneficial effect on microvascular perfusion in vitro. Washing in 1% albumin may represent a new approach to improving the quality of stored red cells, and thus potentially reducing the likelihood of adverse clinical outcomes associated with transfusion of blood stored for longer periods of time.