Media Interview & Articles
The cutting-edge -- but controversial -- research involves implanting modified animal embryos with human "induced pluripotent stem" (iPS) cells that can be coaxed into forming the building blocks of any part of the body.
It is the first step in what researchers caution is a very long path towards a future where human organs for transplant could be grown inside animals.
The research led by Hiromitsu Nakauchi, a professor of genetics at Stanford University, is the first of its kind to receive government approval after Japan changed its rules on implanting human cells into animals.
Human-animal hybrids are to be developed in embryo form in Japan after the government approved controversial stem-cell research.
Human cells will be grown in rat and mouse embryos, then brought to term in a surrogate animal, as part of experiments set to be carried out at the University of Tokyo.
Supporters say the work – led by renowned geneticist Hiromitsu Nakauchi – could be a vital first step towards eventually growing organs that can then be transplanted into people in need.
The research could eventually lead to new sources of organs for transplant, but ethical and technical hurdles need to be overcome.
Nakauchi’s experiments are the first to be approved under Japan’s new rules, by a committee of experts in the science ministry. Final approval from the ministry is expected next month.
Researchers looking for ways to grow HSCs in large numbers in the lab had tried using growth factors without much success. But Nakauchi found that the reason the cells weren’t surviving was impurities in the medium in which the cells were being grown, a human blood protein called albumin. These impurities, mostly proteins released by immune cells, were stopping the cells from growing, says Nakauchi. “How much money, time, and effort has been wasted because of those impurities!” he says.
Nakauchi screened a bunch of polymers that he thought could replace albumin, and found that a synthetic compound called polyvinyl alcohol (PVA), often used in glues, did the trick. PVA has also been used to culture embryos and embryonic stem cells.
News Coverage in Japanese Media
市販「液体のり」、白血病治療の救世主に？ 専門家驚嘆 (https://www.asahi.com/articles/ASM5X6HTMM5XULBJ01H.html)
骨髄移植に使う細胞、大量培養する新手法 東大が開発 / 白血病患者などの治療を後押し (https://www.nikkei.com/article/DGXMZO45440830Z20C19A5CR8000/)
-- Embryo experiments take ‘baby steps’ toward growing human organs in livestock
Primate IPS cells are also more developmentally advanced, or "primed," than the "naïve" rodent stem cells used in the earlier successful chimera experiments. They are therefore less likely to survive in a chimeric embryo, says Nakauchi, who also has a lab at Stanford University in Palo Alto, California. To help primate IPS cells thrive, his Stanford team and collaborators endowed them with a gene that prevents cell death. In the experiments reported last month, they tested how the modified cells would fare in the embryo of a closely related primate species.
-- Radiation-free stem cell transplants, gene therapy may be within reach
Researchers at Stanford and the University of Tokyo may have cracked the code to doing stem cell transplants and gene therapy without radiation and chemotherapy.
“This has been one of my life goals as a stem cell researcher,” said Hiromitsu Nakauchi, MD, PhD, professor of genetics at Stanford. “For 50 years, researchers from laboratories around the world have been seeking ways to grow these cells to large numbers. Now we’ve identified a set of conditions that allows these cells to expand in number as much as 900-fold in just one month. We believe this approach could transform how hematopoietic stem cell transplants and gene therapy are performed in humans.”
-- Japan Okays Research Using Human Cells In Animals
Japan has given the green light to a controversial research process involving implanting animals with human stem cells that could eventually help grow human organs for transplant inside animal hosts.
--New prospects for growing human replacement organs in animals
Mouse pancreases grown in rats generate functional cells that can reverse diabetes when transplanted into mice with the disease, according to new research. The findings show that it may be possible to reduce transplant shortages one day by growing organs from one species in the body of another. Hiromitsu Nakauchi, professor of genetics, is the senior author of the study. The research is highlighted here and in articles from numerous outlets including Discover Magazine, International Business Times (U.K.), Live Science, New Scientist, Tech Times, The Verge, Quartz, a Stanford Medicine press release, and others.
-- Scientists create a part-human, part-pig embryo — raising the possibility of interspecies organ transplants
The study showed that interspecies organ transplants are not only possible but also can be done effectively and safely, said Hiromitsu Nakauchi, a stem cell researcher at Stanford University and the University of Tokyo who is the senior author of the study.
--Embryos that are human-pig hybrids offer hope for patients who need organ transplants
Scientists have grown human cells inside pig embryos, a very early step toward the goal of growing livers and other human organs in animals to transplant into people. This article references another recent study led by Hiromitsu Nakauchi, a professor of genetics, that shows mouse pancreases grown in rats generate functional cells that can reverse diabetes when transplanted into mice with the disease.
-- Rat-grown mouse pancreases help reverse diabetes in mice
Growing organs from one species in the body of another may one day relieve transplant shortages. Now researchers show that islets from rat-grown mouse pancreases can reverse disease when transplanted into diabetic mice.
“We found that the diabetic mice were able to normalize their blood glucose levels for over a year after the transplantation of as few as 100 of these islets,” said Hiromitsu Nakauchi, MD, PhD, a professor of genetics at Stanford. “Furthermore, the recipient animals only needed treatment with immunosuppressive drugs for five days after transplantation, rather than the ongoing immunosuppression that would be needed for unmatched organs.”