Until March, Japan explicitly forbade the growth of animal embryos containing human cells beyond 14 days or the transplant of such embryos into a surrogate uterus. That month, Japan’s education and science ministry issued new guidelines allowing the creation of human–animal embryos that can be transplanted into surrogate animals and brought to term.
The ultimate aim of the research is to use animals, such as pigs, to grow organs that can be transplanted into humans. The relaxed regulations would allow Hiromitsu Nakauchi, a stem-cell biologist at Stanford University in California and the University of Tokyo, to pursue experiments in Japan that he has planned for more than a decade, pending ethical approval. Nakauchi has created pig embryos that are genetically altered so that they cannot produce a pancreas, and he plans to insert induced pluripotent stem cells into the embryos. These cells are obtained by reprogramming human cells so that they revert to an embryonic-like state from which they can form other cell types. The hope is that the stem cells will develop into a pancreas composed mainly of human cells as the embryo develops.
Hiromitsu Nakauchi, who leads teams at the University of Tokyo and Stanford University in California, also plans to grow human cells in mouse and rat embryos and then transplant those embryos into surrogate animals. Nakauchi’s ultimate goal is to produce animals with organs made of human cells that can, eventually, be transplanted into people.
Human–animal hybrid embryos have been made in countries such as the United States, but never brought to term. Although the country allows this kind of research, the National Institutes of Health has had a moratorium on funding such work since 2015.
A team led by developmental biologist Juan Carlos Izpisua Belmonte of the Salk Institute for Biological Studies in La Jolla, California, used CRISPR gene-editing technology to create mouse embryos without the genes that cause organs to form. The scientists then injected rat stem cells into the mouse embryos and implanted the embryos into a mouse’s uterus.
Now for a little history lesson.
Unit 731 was set up in 1938 in Japanese-occupied China with the aim of developing biological weapons. It also operated a secret research and experimental school in Shinjuku, central Tokyo. Its head was Lieutenant Shiro Ishii.
The unit was supported by Japanese universities and medical schools which supplied doctors and research staff.
For 40 years, the horrific activities of “Unit 731” remained one the most closely guarded secrets of World War II. It was not until 1984 that Japan acknowledged what it had long denied – vile experiments on humans conducted by the unit in preparation for germ warfare.
Deliberately infected with plague, anthrax, cholera and other pathogens, an estimated 3,000 of enemy soldiers and civilians were used as guinea pigs. Some of the more horrific experiments included vivisection without anesthesia and pressure chambers to see how much a human could take before his eyes popped out.
It is said that those who refuse to learn from history are doomed to repeat it. It is possible that there are enough safeguards in place to prevent unethical practices in this research, but two questions remain; “Unit 731 has been active for the last 75 years do they now have legitimacy” and; “I wonder where they are going to get the “surrogate uterus”?
It seems as though the only lessons we have learned from history is that we have not learned any lessons from history.
