S-Nitrosylation (SNO) Therapy During Autologous Blood Transfusion

Transfusion is the most common therapeutic intervention employed to maintain and/or improve tissue and end-organ oxygen delivery. Despite the conceptual simplicity of this treatment recent studies indicate that RBC infusion often produces little clinical benefit and may actually harm the recipient by exacerbating rather than correcting anemia-induced tissue hypoxia. The main driver/regulator of tissue oxygenation is blood flow not blood oxygen content. In turn flow into the microvasculature is controlled by small molecules called S-nitrosothiols (SNOs), the most important of which is S-nitrosylated hemoglobin (SNO-Hb). The investigators determined that storage of human blood leads to rapid losses in SNO-Hb that are precisely paralleled by losses in the ability of stored RBCs to dilate blood vessels and thereby deliver oxygen. The investigators have now recently completed an autologous human blood transfusion that confirms the pre-clinical findings in that administration of 1 unit of packed RBCs to young healthy subjects did not improve tissue oxygenation and reduced circulating SNO-Hb levels. This novel mechanism for the loss of physiological activity in banked blood and, more importantly, a putative intervention for its correction, raise the possibility that restoration of NO bioactivity could correct the deficit in oxygen delivery. As such, The Investigators plan to repeat our transfusion study with the addition of administering an S-nitrosylating agent during RBC infusion.