Vascular Microphysiological System for Investigating Endothelial Barrier Function During Organ Preservation and Reperfusion.

Endothelial cell damage after cold preservation and reperfusion injury causes deterioration of the endothelial barrier and ultimately results in edema, leading to transplant failure. Here, a vascular microphysiological system (MPS) is introduced as a testbed to investigate the combinational effect of thermal and fluid perturbations (i.e., wall shear stress) on human endothelial barrier function. Two methods of organ storage are compared: isochoric supercooling (ISC) preservation, which prevents ice formation at subzero temperatures; and, the standard clinical protocol of static cold storage (SCS) at 4 °C. Integrating electrical impedance measurements on chip allow real-time monitoring and quantification of barrier function during preservation and reperfusion protocols. Isochoric supercooling preservation enables longer periods of preservation with superior recovery of barrier function during reperfusion, and has lower metabolic activities compared to static cold storage. Genomic analysis reveals injury and recovery mechanisms at the molecular level for the different preservation and reperfusion conditions. The multifunctional vascular microphysiological system provides a physiologically relevant in vitro model recapitulating ischemia-reperfusion injury to the endothelium. The vascular MPS has potential for optimizing organ preservation protocols, ultimately improving organ transplant viability.