Scientists will try to grow human organs in rodents
A Japanese science project carries the potential for a futuristic resolution to the shortage of organs and organ donors.
Scientists plan to experiment with stem cells to try to create human pancreases in rodents and bring them to full-term, building on research that created part-human, part-pig embryos, Japan’s Asahi Shimbun newspaper reported Thursday.
Final approval from the country’s science ministry is likely this month, according to the British scientific journal Nature.
In the study, researchers from the University of Tokyo will manipulate rodent genes to create fertilized eggs in rats and mice. They will place human cells into those fertilized eggs, creating “animal-human embryos.”
Though the scientists don’t expect to create human organs immediately, “we are in a position to start serious studies in this field after 10 years of prepara
tion,” Hiromitsu Nakauchi, a stem cell biologist at Stanford University and the University of Tokyo, told Asahi Shimbun.
“This allows us to advance our research based upon the know-how we have gained up to this point,” Nakauchi said.
Nakauchi told Nature that he plans to proceed slowly, not attempting to bring hybrid embryos to term for some time.
Guidelines for this research reversed a Japanese government decision banning such studies out of concern it could lead to organisms that have a mix of animal and human genes, according to The Japan Times. The International Society for Stem Cell Research applauded the decision when the guidelines were announced in March.
“Responsibly conducted research using chimeric embryos will allow scientists to gain a better understanding of human development and disease,” ISSCR President Doug Melton said in a news release. “Japan’s new rules will enable a new generation of research that could potentially lead to the production of human organs for transplantation and other advances in the field of regenerative medicine.”
The guidelines allow such studies on the condition that researchers take appropriate steps to prevent the birth of an ambiguous creature that could be part human – an event Nakauchi said is probable only in the realm of sci fi.
“The number of human cells grown in the bodies of sheep is extremely small, like one in thousands or one in tens of thousands,” he told Asahi Shimbun, referring to his previous experiments. “At that level, an animal with a human face will never be born.”
In 2016, researchers at the University of California, Davis created part-human, part-pig embryos but allowed embryos to develop for only 28 days inside female pigs before terminating the pregnancies and studying the tissue.
Jiro Nudeshima, a life science specialist who focuses on ethical concerns, expressed doubts about the validity of the Japanese research.
“If the goal of such studies is to discover a therapeutic application for humans, experiments on rats and mice are unlikely to produce a useful result because the size of the organ will not be sufficient, and the result will be a far cry from humans anatomically,” Nudeshima told Asahi Shimbun.
Though regenerative medicine is growing, creating complete human organs is complicated and has not been achieved by any scientist.
“Regenerative medicine is still a relatively young field, and it’s still early days,” Andy McMahon, a regenerative medicine expert at USC, said in a news release in April 2018.