Science Daily reports:
In a study with significant implications for human organ transplantation, researchers have successfully grown functional mouse kidneys inside rats from just a few donor stem cells.
The results of the study, led by researchers from the National Institute for Physiological Sciences in Japan, will be published in an upcoming issue of Nature Communications. For patients with end-stage renal disease, a kidney transplant is the only hope for regaining quality of life.
Yet many of these patients will never undergo transplant surgery thanks to a chronic shortage of donor kidneys. With 95,000 patients on the waiting list for a donor kidney in the United States alone, demand far outstrips supply.
The Japan Times reports:
The process of growing human organs in animals poses an ethical conundrum because human stem cells could develop into brain or reproductive organ cells in the host. “The main ethical concerns are the risk of consciousness and/or gamete (reproductive cell) production,” said Masumi Hirabayashi, an associate professor at Japan’s National Institute for Physiological Sciences who supervised the study.
“There are serious technical barriers and complex ethical issues that must be discussed and solved before producing human organs in animals,” he added. Pigs are usually considered the best hosts for human organ regeneration, but pig embryos only develop for 25 weeks, unlike the 40 weeks that human babies grow, meaning the species might not be suitable for growing organs in embryos. Cattle, with a 40-week gestation, could be another option.