Japanese scientists have developed a process for forming a chimeric embryo by planting a human stem cell into an animal embryo, usually a pig. The organs would then mature inside the animal until scientists harvest and transplant them into a human body.
Led by Professor Hiromitsu Nakauchi of the University of Tokyo, they want to plant the embryo in a female pig’s womb, inducing pregnancy and creating a new-born pig with human organs such as pancreas or liver. The organs would then mature inside the hybrid offspring as it grows until it is slaughtered and scientists harvest the organs and transplant them into a human body.
Creating the chimeric embryo is legal, but so far implanting it in an animal’s womb is not. Right now, a Japanese regulatory body is deciding whether to lift the ban on implanting chimeric embryos in animals, and these scientists are confident they could successfully grow a pig with human organs within a year if they win approval.