Xenotransplantation in 2008

Transplantation is the gold standard of care for end-stage organ failure. For example, two-year mortality in patients with advanced class III or IV heart failure exceeds 50%, compared to five- and ten-year survival rates of 82% and 62.5%, respectively, for heart transplant recipients. A major donor shortage has resulted in 95,000 registered patients waiting for an organ transplant in the US. At this time, xenotransplantation is a promising potential solution to this donor shortage. Xenotransplantation is defined as any procedure that involves transplantation, implantation, or infusion into a human recipient of live cells, tissues, or organs from a non-human animal source. Most recent research efforts use the pig as a solid organ donor for heart, kidney and liver transplantation, and as a source of pancreatic islets. The barriers to successful xenotransplantation include the immunology of xenograft rejection, physiological differences between the pig and the human, and the possibility of cross species infectious disease transmission. The field of xenotransplantation has come a long way, with survival of xenograft organs having been extended from minutes to months at the present time. The FDA and ISHLT have recommended that a median orthotopic xenograft survival of 90 days could result in initiation of clinical trials. This goal may be achievable within the next few years. Successful clinical xenotransplantation would change the face of modern medicine.