Hydrogen Sulfide in Experimental Organ Transplantation: From Bench to Bedside

Organ transplantation is the treatment of choice for patients with organ failure. However, the long-term success of this complex life-saving procedure is severely challenged by several inherent factors such as ischemia-reperfusion injury (IRI), an unavoidable pathological condition which occurs due to temporary cessation of blood supply to the donor organ during procurement and cold preservation, and subsequent blood restoration upon engraftment. IRI decreases organ graft quality and function and increases the incidence of post-transplant complications. While the transplant community has adopted the use of sub-optimal organ grafts from extended criteria donors and deceased donors in addition to viable organs from healthy living donors to expand the pool of transplantable organs with the aim to overcome the global organ shortage crisis, the sub-optimal organs are more susceptible to IRI. Also worrying is the fact that organ preservation techniques have not changed for over the last 50 years, suggesting the need to optimize existing preservation techniques or develop effective alternative preservation solutions to limit ischemic injury during organ graft preservation. Among several pharmacological agents being tested in preservation solutions in the pretext of improving transplantation outcomes, hydrogen sulfide (H₂S), the third established member of a family of gaseous signaling molecules, is emerging as an excellent candidate, with therapeutic properties such as antioxidant, anti-inflammatory, anti-apoptotic, and vasodilating properties. In this chapter, we discussed the therapeutic benefits of H₂S and its donor compounds against IRI in various experimental models of organ transplantation. In fact, one of the H₂S donor compounds, sodium thiosulfate, which our research team is currently investigating in experimental kidney transplantation, is already in clinical use. Therefore, it is a question of repositioning it for clinical organ transplantation after substantial evidence of its protective effects in experimental organ transplantation.