Humans May Receive Organ Transplants from Pigs
Well-known scientist Robert Winston from the UK is setting up a lab to breed pigs with special organs that could one day be transplanted into humans who would otherwise die. The first genetically modified pigs could be bred in two years, and the first pig-human transplant might occur in the next decade.
There is a worldwide shortage of organ transplants. In the US alone, about 100,000 people are waiting for a transplant, and about 60% of these individuals will die on the waiting list. Winston's pigs, however, would have a supply of organs--hearts, livers, kidneys, and more--ready for those who are most desperate.
Winston and his colleagues from the Imperial College of London have already created pigs with genetically modified sperm. However, the group is still waiting for permission from the EU to breed the animals. The researchers then plan to genetically alter the sperm so that the pigs' organs won't be rejected by a human immune system. The method would alter certain molecules on the surface of organs, in effect cloaking the organ so that the origin would be hidden from the human immune system.
Animals with foreign genetic material are described as "transgenic." The researchers chose pigs because their hearts are similar to those of humans in size, shape and structure. Today, pig heart valves are regularly used in human heart surgery, after they have been stripped of their tissue to prevent rejection by the immune system.
The proposal has critics, of course. Some warn that, even if the complicated immunology can be accomplished, there is no guarantee that animal organs would actually work inside a human body. Some also fear that animal organs may carry viruses into the human body. Another concern centers on the different lifespan of animals, and the different aging rate of their organs, compared with a human's aging rate.
The concept of "xenotransplantation," or transplants of organ or tissue from one species to another, has long fascinated scientists and others. However, nearly every attempt at such a transplant has been fairly unsuccessful. As far back as 1682, bone from a dog was used to repair the skull of a Russian aristocrat. As for the days of modern science, in 1906 French doctors grafted kidneys from goats and pigs onto people with kidney failure, but the organs lasted only an hour. Other attempts have also been short-lived, although xeontransplantation with genetically modified animals began only in 1995.
In addition to growing organs for transplants, the organs could also be used for testing new medications, giving results that would be more similar to human reactions than a normal animal organ would give. Xenotransplantation would serve as an alternative to stem cells, which can potentially generate new tissue for any organ in the body.
As for the animals' rights, Winston explained that the group intended to raise the pigs to maturity in a healthy and happy environment, and, when the time came, their organs would be used to save a human's life.