Storage duration and white blood cell content of red blood cell (RBC) products increases adhesion of stored RBCs to endothelium under flow conditions

BACKGROUND: Adherence of red blood cells (RBCs) to vascular endothelium impairs blood flow and decreases oxygen delivery. Although RBCs may be stored for up to 42 days before transfusion under current blood banking guidelines, little is known of how changes to RBCs during storage may affect their adherence properties. The influence of RBC product storage time and white blood cell (WBC) burden on the adherence of RBCs for transfusion to vascular endothelium under conditions of continuous flow was investigated in this study. STUDY DESIGN AND METHODS: RBC samples were collected from nonleukoreduced (S-RBC), buffy coat-poor (BCP-RBC), and leukofiltered (LF-RBC) products at fixed time points during storage. Samples were perfused, at controlled shear stress and temperature, across a confluent endothelial cell (EC) monolayer with a parallel-flow chamber mounted to an inverted microscope. RBC-EC interactions were recorded with a digital camera attached to the microscope. RESULTS: The number of RBCs adhering to the EC layer increased significantly with storage time in all RBC products; however, WBC reduction delayed this increase. LF-RBCs were also significantly less adherent than S-RBC or BCP-RBC products on Day 1 of storage (p < 0.05). The strength of RBC attachment to vascular endothelium was significantly stronger in S-RBC products compared to BCP-RBC and LF-RBC products. CONCLUSION: Our findings indicate that product storage time and WBC burden increase the number and strength of adhesion of RBCs to vascular endothelium. These results may lead to greater understanding of the interaction of transfused RBCs with recipient endothelium and the biologic consequences of this adherence.