Microfluidics: A high-throughput system for the assessment of the endotheliopathy of trauma and the effect of timing of plasma administration on ameliorating shock-associated endothelial dysfunction

Early resuscitation after trauma-hemorrhagic shock with plasma rather than crystalloid may ameliorate systemic endothelial cell (EC) injury and dysfunction (endotheliopathy of trauma). We postulated that endothelial-lined microfluidic networks would be a useful platform to study the EC activation/injury under flow conditions to mimic trauma-hemorrhagic shock. We then used the microfluidic system to further characterize the protective effects and optimal timing of plasma infusion on the development of "endotheliopathy of trauma" in our model. Human umbilical vein ECs were added to microfluidic flow channels, and after overnight perfusion, the cells were subsequently treated with epinephrine and exposed to hypoxia reoxygenation. Media alone or 5% human plasma was perfused either immediately following treatment (early plasma) or after a 3-hour delay (late plasma). Glycocalyx injury was indexed by fluorescent microscopy and shedding of syndecan 1 and hyaluronic acid. Endothelial markers of activation/injury were also measured and included soluble thrombomodulin, tissue plasminogen activator, plasminogen activator inhibitor 1, and angiopoietins 1 and 2. Sheddase activity was indexed by ADAM metallopeptidase domain 17. Endothelial cell and glycocalyx barrier function studies using microfluidic devices are a more realistic model of the glycocalyx endothelial vascular barrier than studies performed on ECs using static (no flow) conditions. Conditions that mimic the internal milieu following hemorrhagic shock result in glycocalyx degradation and an inflammatory prothrombotic response by the endothelium. "Early" use of plasma in the microfluidic channel perfusate mitigated against these effects. Later perfusion with plasma had no protective effect. A temporal effect to plasma administration was noted in our biomimetic model of the endothelial vascular barrier following shock. This suggests a protective role to "early" plasma administration in the severely injured patient.