Hydrogen, a potential safeguard for graft-versus-host disease and graft ischemia-reperfusion injury?

Post-transplant complications such as graft-versus-host disease and graft ischemia-reperfusion injury are crucial challenges in transplantation. Hydrogen can act as a potential antioxidant, playing a preventive role against post-transplant complications in animal models of multiple organ transplantation. Herein, the authors review the current literature regarding the effects of hydrogen on graft ischemia-reperfusion injury and graft-versus-host disease. Existing data on the effects of hydrogen on ischemia-reperfusion injury related to organ transplantation are specifically reviewed and coupled with further suggestions for future work. The reviewed studies showed that hydrogen (inhaled or dissolved in saline) improved the outcomes of organ transplantation by decreasing oxidative stress and inflammation at both the transplanted organ and the systemic levels. In conclusion, a substantial body of experimental evidence suggests that hydrogen can significantly alleviate transplantation-related ischemia-reperfusion injury and have a therapeutic effect on graft-versus-host disease, mainly via inhibition of inflammatory cytokine secretion and reduction of oxidative stress through several underlying mechanisms. Further animal experiments and preliminary human clinical trials will lay the foundation for hydrogen use as a drug in the clinic.