Scientists have found a way to grow a human organ in the body of a sheep, which could save hundreds of lives per year.
In an extraordinary new development that has huge implications for organ donorship that could save lives, scientists have managed to create the first human donor organ inside the body of a sheep. Scientists hope this could clear a backlog of thousands of patients who wait for a life-saving organ.
Scientists even believe that this could possibly lead to the first human transplant within only five years, a development that could save hundreds of lives each year. Scientists would grow human cells within the body of a sheep to create a viable human organ that could be then implanted within a human body.
With hundereds of people dying on the waiting list each year, this would obviously have a huge impact on the medical community. But there are some significant doubts about whether such organs would be viable and whether the body would reject the implant as soon as it was put in place.
“Even today the best matched organs, except if they come from identical twins, don’t last very long because with time the immune system continuously is attacking them,” said Dr Pablo Ross from the University of California, Davis, according to a Guardian report. “For a pig we typically transfer 50 embryos to one recipient. With the sheep we transfer four embryos to one recipient.”
Ross added that he had some concerns about where the human cells end up in the chimera.
“Let’s say that if our results indicate that the human cells all go to the brain of the animal, then we may never carry this forward,” he said.
The following is an excerpt from Wikipedia on the subject.
Xenotransplantation (xenos- from the Greek meaning “foreign”), is the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenografts or xenotransplants. It is contrasted with allotransplantation (from other individual of same species), syngeneic transplantation or isotransplantation (grafts transplanted between two genetically identical individuals of the same species) and autotransplantation (from one part of the body to another in the same person) .
Xenotransplantation of human tumor cells into immunocompromised mice is a research technique frequently used in pre-clinical oncology research.
Human xenotransplantation offers a potential treatment for end-stage organ failure, a significant health problem in parts of the industrialized world. It also raises many novel medical, legal and ethical issues. A continuing concern is that many animals, such as pigs, have a shorter lifespan than humans, meaning that their tissues age at a quicker rate. Disease transmission (xenozoonosis) and permanent alteration to the genetic code of animals are also causes for concern. A few successful cases of xenotransplantation are published.
It is not uncommon for patients and physicians to use the term “allograft” imprecisely to refer to either allograft (human-to-human) or xenograft (animal-to-human), but it is helpful scientifically (for those searching or reading the scientific literature) to maintain the more precise distinction in usage.
The first serious attempts at xenotransplantation (then called heterotransplantation) appeared in the scientific literature in 1905, when slices of rabbit kidney were transplanted into a child with renal insufficiency. In the first two decades of the 20th century, several subsequent efforts attempts to use organs from lambs, pigs and primates were published.
Scientific interest in xenotransplantation declined when the immunological basis of the organ rejection process was described. The next waves of studies on the topic came with the discovery of immunosuppressive drugs. Even more studies followed Dr. Joseph Murray’s first successful kidney transplantation in 1954 and scientists, facing the ethical questions of organ donation for the first time, accelerated their effort in looking for alternatives to human organs.
In 1963, doctors at Tulane University attempted chimpanzee-to-human kidney transplantations in six people who were near death; after this and several subsequent unsuccessful attempts to use primates as organ donors and the development of a working cadaver organ procuring program, interest in xenotransplantation for kidney failure dissipated.
An American infant girl known as “Baby Fae” with hypoplastic left heart syndrome was the first infant recipient of a xenotransplantation, when she received a baboon heart in 1984. The procedure was performed by Leonard L. Bailey at Loma Linda University Medical Center in Loma Linda, California. Fae died 21 days later due to a humoral-based graft rejection thought to be caused mainly by an ABO blood type mismatch, considered unavoidable due to the rarity of type O baboons. The graft was meant to be temporary, but unfortunately a suitable allograft replacement could not be found in time.
Xenotransplantation of human tumor cells into immunocompromised mice is a research technique frequently used in oncology research. It is used to predict the sensitivity of the transplanted tumor to various cancer treatments; several companies offer this service, including the Jackson Laboratory and Altogen Labs.
Human organs have been transplanted into animals as a powerful research technique for studying human biology without harming human patients. This technique has also been proposed as an alternative source of human organs for future transplantation into human patients. For example, researchers from the Ganogen Research Institute transplanted human fetal kidneys into rats which demonstrated life supporting function and growth.
