A science ministry committee of experts on Wednesday approved Japan’s first research involving the injection of human induced pluripotent stem (iPS) cells into fertilized animal eggs with the aim of growing human organs.
The project led by Hiromitsu Nakauchi, a professor at the University of Tokyo, is expected to receive the final go-ahead by the ministry in August.
The government in March lifted a ban on research where human cells are placed into fertilized animal eggs, then planted back inside the animals so they can give birth.
In June, the team submitted its research plan to the ministry after getting approval from an ethics committee.
The team aims to use human organs obtained through the method for transplantation in the future.
In similar research in the United States, only a small number of human cells were included in the resulting animal fetuses.
The Japanese team will start its experiment using mice and rats.
Human iPS cells will be placed into fertilized eggs of such animals and be genetically modified so as not to create specific organs.
The team will examine to what extent human cells are mixed into the resulting fetuses. The animals that are born will be kept for up to two years to monitor the conditions of their organs.
In the future, the team will try to grow human organs inside the bodies of pigs, whose organs are similar in size.
The team succeeded in improving diabetic symptoms in mice by transplanting mice pancreases grown inside the bodies of rats into them. But it is believed to be difficult to grow human organs inside mice and pigs because of the genetic differences.
“Our research was approved at last after sufficient discussions,” Nakauchi said.