Friday, January 27, 2017

Scientists have created an embryo with human cells and pig – RIA Novosti

27.01.2017

(updated: )

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MOSCOW, 27 Jan — RIA Novosti. an international group of geneticists for the first time created a full-fledged chimeric embryos, in which pigs combined with human cells and other mammals. This opens the way to growing human organs in animals body, said in an article published in the journal Cell.

“Work on this problem took four years. We clearly underestimated just how much effort will be needed to implement this task. This is the first important step toward growing human organs in a pig’s body. Now we need to figure out how to make human cells turn into the right bodies to implement our real goal is to learn how to grow transplanted organs,” said Juan Belmonte (Belmonte, Juan) from the Salk Institute in La JOLLA (USA).

About 15 years ago biologists began an active discussion of the possibility of so-called xenotransplantation — the transplant of animal organs into the human body. To implement this idea as it seemed a scientist need to solve a simple problem — to make the immune system not to reject other people’s bodies.

© Juan Carlos Izpisua Belmonte Lab /Salk Institute

as you might guess, is still not found, although genetics are developing specific methods to make the bodies of pigs and other animals invisible to the human immune system. Just last year, the famous American geneticist George Church has approached this task by removing part of the label of “friend or foe” with the help of the genomic editor CRISPR/Cas9.

© Photo: Wu et al. / Cell 2017

the procedure of growing pigs with human organs

Belmonte and his colleagues used the same system for solving the problem method “on the contrary” — by growing human organs for transplant inside the body of a pig. Such bodies can be created, if you enter in a fetal pig human stem cells in a strictly defined period of development, received a so-called Chimera — an organism with two or more sets of heterogeneous cells.

Such experiments, as they say scientists, has been successfully conducted on mice, but large animals such as pigs or monkeys, experiments have not yet been done, or was unsuccessful. Team Belmonte made a big step towards the realization of these tasks, learning to implement virtually any cells in fetal pigs and mice by using CRISPR/Cas9.

This editor is DNA used as a “killer” of selectively killing the cells of the embryo at the time of formation of an organ. Then the scientists injected cultured stem cells of other species that fill a niche and turn into the body “blank” which was destroyed. Other tissues and organs are not affected, which is important for ethical reasons.

check this technique on mice and grow them rat pancreas, scientists have spent nearly four years on its adaptation for work with human and porcine cells. The problem was that a pig fetus is growing three times faster than a human, and Belmonte and his colleagues spent a long time picking the right time frame for implantation of human cells.

solve this problem, the researchers replaced the future the cells of the muscles in dozens of pig embryos and implanted them back into the wombs of foster mothers. About two-thirds of the embryos successfully developed throughout the month, and then scientists had to stop the experiment for ethical reasons in accordance with us law.

This success, as noted by Belmonte, opens the way for the creation of a full human organs, ready for transplant and not is shed by the body. Now Belmonte and his colleagues are working on adapting CRISPR/Cas9 for in the body of the sow and obtaining all necessary permits for such experiments.

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