The idea of transplanting human organs and tissues has captured the imagination of successive generations. The first successful transplantation was a kidney transplantation performed between identical twins by Joseph Murray and his colleagues.
With the significant progress, it might even be possible to transplant non-human tissues from animals such as pigs in some 5 years from now. This process of transplanting organs and tissues and tissues from one species to another is called as Xenotransplantation. This is one area that has great potential to revolutionize the ever-fascinating subject of human transplantation. The biggest obstacle in the way of safe transplants is close to being swept away by new advances.
Normally planting a pig organ such as a kidney in a human triggers an immediate and deadly immune response. Attempts have been made to breed "safer" pigs but very little success has been reported so far. Patients given organs from these animals would still need their immune systems to be strongly depressed.
Scientists are now working on how to trick the immune system from recognizing the foreign material transplanted or to rather teach the immune system to accept the transplant. One way is to produce pigs lacking a sugar called "gal epitope" which is targeted by immune system antibodies. Another is to mimic the natural process by which the body learns to inactivate cells that might attack parts of itself.
Experiments conducted on pig kidney transplants to other animals targeting the above strategies have shown that the survival rate is more than 80 days, which is a very promising finding.
Previous experiments conducted had shown the survival rate to be not more than a few hours. The above finding has a significant implication on the long-term graft survival rate following transplantation. Indeed, the majority of graft losses in this kidney transplant model resulted not from rejection but from the death of the animal from some other cause.
With our improved understanding of immunity and rejection, it might be possible to overcome many of the immunological complications in the future, eventually opening the gateway to Xenotransplantation.