Scientists have long dreamed to grow human organs in the bodies of animals, in order to provide those in need of heart transplants, lungs, kidneys and other organs. A glimmer of possible success in this difficult target was recently spotted.
Using the technology of stem cells, the researchers generate human cells and tissues in the embryos of pigs and cattle. Their study appeared in the journal Cell. The project started with a research group that is trying to prove that it is possible to grow cells on a single animal within a different species. This is known as a Chimera, especially inter-species Chimera, an organism that contains cells from two or more types.
They started with two closely related species: rats and mice. To create a Chimera of the rat, mouse, scientists began with the creation of the mouse embryo without the pancreas. Similar work was done earlier by other scientists in the Stanford who bred mutant mice that lacked a pancreas, and then raised the pancreas of rats inside the mouse.
In the current study, the researchers used a gene editing methods, known as CRISPR / cas9 to create mouse embryos deprived of the pancreas. Then they put the stem cells rats that contained the gene for the pancreas in these mutant embryos. After implantation, the stem cells turned into the pancreas of rats inside the mouse embryo, which ultimately (and importantly) grow up in healthy mice with a normal lifespan. Taking their idea and making it a few steps further, the researchers used the same method to develop the eye of rats and the hearts of the rats into mice embryos.
Human cells in some of the embryos began to specialize and become the predecessors of the fabric. However, the probability of success and the level of contributions of human stem cells in pigs was significantly lower than with chimeras of the rat, mouse. Although the experiment with human stem cells was terminated on day 28, this remains the first case in which human stem cells begin to grow within another species. Thus, it is a small but important step towards the ultimate goal of growing human organs in animals.