Red blood cell storage and adhesion to vascular endothelium under normal or stress conditions: An in vitro microfluidic study.

Background: Observational studies have identified an association between duration of red blood cell (RBC) storage and adverse outcomes in trauma. Hemorrhagic shock (HS) leads to impaired tissue perfusion which is associated with endothelial cell glycocalyx (eGC) shedding. Adhesion of stored RBC to the vascular endothelium has been shown to lead to impaired perfusion in the microcirculation and contribute to organ failure and poor outcome. The role of either or both of the EC and RBC glycocalyx in this process is unknown and was studied in an in vitro model.

Methods: Human umbilical vein endothelial cells were perfused in a microfluidic device with RBC solutions from fresh, less than 14-day or longer than 21-day storage. In some experiments, the HS microenvironment was simulated by hypoxia-reoxygenation (H/R) and epinephrine (Epi) in the perfusion experiments. Measurements obtained included endothelial cell (EC) and RBC glycocalyx and RBC adherence to human umbilical vein endothelial cell monolayers at variable shear rates.

Results: Endothelial cell glycocalyx and RBC glycocalyx dimensions were reduced by H/R and Epi and storage duration respectively. Red blood cell adherence to the endothelium was increased by H/R + Epi treatment and duration of RBC storage.

Conclusion: Our data may help explain some of the remaining discrepancies regarding the impact of RBC storage duration on outcomes in the trauma population. Consideration of the integrity of the EC and RBC glycocalyx may guide future transfusion strategies in the trauma population. The microfluidic device system platform may offer a high throughput modality to study emerging therapies to mitigate adverse consequence of RBC storage duration on the perfused endothelium in the trauma setting.