Development of Capillary-on-Chip for the Study of Preservation Injury on Microvascular Endothelial Cells - Abstract: With nearly 90% of the demand for organ transplantation not being met worldwide, there is a current crisis in the field of organ transplantation. A critical bottleneck preventing the expansion of transplant is that current limits in preservation times are in the timescale of hours rather than days. This lack of storage time is perhaps most critical in vascular composite allograft (VCA) transplantation, as longer times are needed for immunologically and aesthetically matching the donor and recipient. This is even more so recently as novel mixed-chimerism based tolerance induction protocols require the donor organ to be kept viable for several days. Literature has shown that ischemic reperfusion injury (I/R) is a significant component of this preservation related damage. Though it has been well documented that endothelial cells are extremely susceptible to I/R, there has been little work done to study this in the context of organ preservation. Furthermore, our group has observed significant endothelial damage, particularly in the microvasculature following static cold storage preservation, the current clinical standard. As such, it is imperative that we better understand the effect of preservation injury on the microvasculature and develop novel therapeutic strategies to treat these cells as a means to increase patient access to organ transplant. In this study, we aim to establish a microfluidic model of the microvasculature to determine the effects of preservation injury on primary microvasculature endothelial cells (MVECs) and how this differs from their macrovascular counterparts. We further plan to alleviate this damage via apoptosis inhibition. Our first aim will be to develop a microfluidic device to dynamically observe the detrimental effects of preservation injury on rat primary MVECs and how this differs from macrovascular endothelial cells. Once the device has been developed and optimized we will test novel methods to alleviate the preservation injury observed through apoptosis inhibition. Our final goal will be to ascertain whether the preservation damage, and subsequent treatments are conserved at the total organ level, with VCA being our model of choice due to their increased susceptibility to endothelial damage. This will be accomplished through the use of an ex vivo machine perfusion rat hindlimb model of VCA preservation and recovery. The completion of the proposed project will provide critical in vitro, and ex vivo results for the effect of preservation injury on the microvasculature and how to remedy it. Additionally, the study will lead to the development of a physiologically relevant benchtop model of vasculature preservation that can be easily adapted for other organs such as the heart, lungs, and kidneys. Furthermore, the results from this study will provide critical preliminary data for the basis of a planned K99/R00 Grant application that will enable the applicant to develop a co-culture microfluidic model and to perform a preclinical in vivo study. Finally, the work in this study will serve as an excellent opportunity for the applicant to receive surgical training that will be critical for his career development.
