"Humanimales": Japan wants to be the first country to support its development

Last March, the Japanese government gave the go-ahead for scientist Hiromitsu Nakauchi, who heads research groups at the University of Tokyo (Japan) and Stanford (USA), to develop human organs. in animals from human stem cells.

The idea is not a pioneer, but it's the first time that a government supports such experiments, according to Nature magazine.

Previously, in the United States and other countries, attempts have been made to cultivate human cells in mouse, rat and even sheep embryos, and then transplant these embryos into surrogate animals. In any case, however, the experiments were interrupted, whether due to legal obstacles or trial failure.

Japanese Government Permit

In March, following a request from the Nakauchi team, the Japanese Ministry of Education and Science released new guidelines for stem cell research that would allow the creation of human-animal embryos that could to be transplanted into surrogate animals. futures.

In any case, the final decision depends on a committee of experts from the Ministry of Science and will be announced in August.

But Nakauchi badures that the change already allows him to advance in his investigations, whose ultimate goal, he badures, is to produce human organs that are lacking, such as the pancreas, and that Once developed, they can be transplanted from one animal to another.

Objections

But the process will be slow and not without obstacles: scientific and ethical.

Stem cell experiments are, in many cases, a cause for controversy.

According to Nature magazine, some bioethicists fear that human cells can only be used for the development of the organ concerned and reach the developing brain of the animal, thus affecting their development. cognitive abilities

Nakuchi says that the experiment is designed so that "stem cells only enter the pancreas" and that in addition, it will not attempt, in the first place, to graft an embryo hybrid, but will first cultivate hybrid mouse embryos for about 14 days. Almost all animal organs are formed.

Then he will do the same thing in rats, he tells them, allowing them to grow for 15 days. Later, he will do it with the pigs, where he will need 70 days to cultivate hybrid embryos.

But not everyone is convinced by the plans of the Japanese scientist.

Researcher Jun Wu, of the University of Texas (USA), states that it is pointless to carry out human-animal hybrid embryos using species far removed from evolution, such as the pigs and sheep because "human cells will be eliminated in the initial phase of the experiment".

Just this week, the Spanish newspaper El País publishes the progress of the work of a group of Spanish scientists who claim to have created chimeras of men and monkeys in China, but many details remain to be seen. know until the result of the experiment is published soon. in an international scientific journal that they did not reveal.

BBC