The impact of transfusion of fresh versus stored RBCs is still a matter of debate. In the present study, an ex vivo animal model was used, in which NO-mediated vasodilation could be controlled and sensitively monitored to assess the impact of RBC units stored up to 42 days. Fresh RBCs added to aortic rat rings substantially stimulated NO-mediated vasodilation while stored RBCs did not. The results support the insufficient NO bioavailability hypothesis which postulates that both changes occurring in RBC units during storage and pathologic processes in the recipient of a transfusion possibly cause adverse clinical outcomes.

– Rainer Moog