Strategies to Reduce Ischemia Reperfusion Injury in Vascularized Composite Allotransplantation of the Limb.

An important and often underinvestigated contributor to solid organ transplant rejection is ischemia reperfusion injury. This pathophysiological response releases damaging reactive oxygen species and cell stress signals that initiate inflammation, which has a critical role in priming the immune system for allorecognition. In time, this renders graft dysfunction and how this response is mediated in composite tissues remains unknown. Current protocols are drawn from solid organ transplantation with little scientific basis as to how this informs current hand transplantation practices. In addition to preservation flush and allograft cooling, machine perfusion is placing itself experimentally as a concept that could act to promote viability and increase the critical ischemic window, which is especially beneficial at a time of limited donors. With the increasing prevalence worldwide of hand transplantation, we review the potential contribution of ischemia reperfusion injury to hand allograft rejection including both current and experimental strategies.