Xenotransplantation
From ArticleWorld
Xenotransplantation is the transplantation of tissues or organs from an individual of one species to an individual of another species.
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Indications
The idea of xenotransplants appeared in the context of a worldwide shortage of human organs. More than half of the patients who need an organ transplant die waiting for one.
Xenotransplants are still difficult to perform, because the mechanism of organ rejection is yet unclear when dealing with organs of different species. However, some organs have been successfully transplanted from pigs to human, and the transplant of a baboon heart has had short-term success. Pig livers have been successfully used (externally, however) until a human donor was found.
Risks
The greatest risk involved in xenotransplant operations remains the one of rejection. Rejection risk is very high in case of transplants from the same species, as the genetic differences are high enough to trigger aggressive reactions from the immune system. In the case of xenotransplants, this risk is even higher, and it is the main reasons why hyperacute rejections are often overwhelming for the human organism. Some researchers are currently investigating the possibility of creating transgenic animals with some human markers, in order to make organs genetically closer to their human counterparts.
Medical researchers also fear that xenotransplants may spread some diseases, including those to which humans are currently immune. The canonical example is that of porcine endogenous retroviruses.
Ethical issues
Ethical issues involved in xenotransplants have been subject to a great number of debates to an already transplant-questioning world. Many animal-rights activists considered the killing of animals for human transplants to be as barbaric as killing humans for organs. Some religions also question the ethics of such a transplant, especially some oriental religions that see animals as an inferior step in the reincarnation cycle when compared to humans.
Future development
Most medical issues are currently being eliminated, with the advancements in the field of xenotransplant. The greatest problem seems to be the reticence of human receivers against having animal tissues or organs inside their bodies. In time, this should disappear though, and researchers are confident in the future widespread of xenotransplantation, rendering it as a mainstream technique.