The first sheep embryos, which contain human cells, have created scientists in the United States. For every 10,000 sheep cells, one is human. It has been preceded by the same scientists as the creation of human fetal pig embryos with a smaller proportion of a human cell for every 100,000 pigs.
The new achievement, announced by Dr. Pablo Ross of the University of California-Davis at a meeting in Austin, Texas, is another step towards organ transplantation that has been developed inside animals.
As this passes from the stage of science fiction to that of reality, the number of organs available for transplantation will increase significantly. And since the organs will have grown inside the animals but are composed of patient cells, it is assumed that they will not be discharged as a foreign body by its immune system after transplantation.
The new method is different from the known xenotransplant, in which an organ belonging to an animal is transplanted into man, since in this case the graft is foreign to the human organism.
“Today, even the most appropriate organs, with the exception of what comes from identical twins, do not last long, because over time the immune system is constantly attacking them,” said Ross, according to the British Guardian.
Brew Whitlow, a professor of animal biotechnology at the Scottish Institute of Roslin, where the first cloned sheep was created, said that it was a long way to go before human organs were grown in animals and later transplanted into patients, but marked the new achievement of embryo production with human cells as a “significant step”.
So far, researchers have allowed these embryonic “chimeras” of sheep-human and swine-humans to live up to 28 days (21 in the animal). Their aim is to extend this time to 70 days, but they will need special approvals for this.
Ross estimated that in order for their method to work, at least 1% of the animal’s fetal cells must be of human origin; therefore, the proportion of human-animal cells should be further increased from one to 10,000 today in the one to 100. Sheep have some organs like the heart and the lungs, which resemble human beings. Like pigs, sheep develop organs of approximately the same size as human beings.
Surveys go on with both pigs and sheep, but bioethical concerns grow, among other things, if these “chimeras” end up showing brain and mind with human characteristics. He acknowledged that he was a source of permanent concern about exactly where the human body will end up in the human body, which is introduced into their bodies.
On the other hand, researcher Dr. Hiro Nakautsi of Stanford University in California said he was optimistic that in five to ten years people would now be able to receive human animal implants. At the same time, he was reassuring about the possible side effects in the “chimeras”, saying that “so far the human cell contribution is very small. We are not talking about a pig with a human face or human brain. We can target the area we want, and so we are able to avoid human cells being converted into brain cells of the animal or into its germ cells. ”
But other scientists, such as cell biologist Robin Lavelle-Batz of the Francis Kick Institute in London, have expressed fears that viruses inside the DNA of animals can pierce the organ with the human cell and after transplanting infect humans. They also stated that the human organ of the animal may contain blood vessels with mixed animal cells, so it will again be discarded by the patient’s body after transplantation.
However, researchers argue that through genetic modification it is possible to create animals without dangerous viruses, and human cells can completely replace any animal cells after organ transplantation. But all this remains to be confirmed in practice.