Mice stem cells used in kidney research
Scientists said on Wednesday they have successfully used mice stem cells to grow kidneys in rat embryos, using a technique that could one day help grow human kidneys for transplant.
But the researchers cautioned that their success was only a first step and that “serious technical barriers and complex ethical issues” remain before the process could be used for human organs.
The technique has previously been used to grow mice-derived pancreases in rats, but the new study is the first evidence that it could one day provide a solution to the massive shortage of donor kidneys with renal disease.
The research, published Wednesday in the Nature Communications journal, began with the development of a suitable “host” in which the kidneys could be grown.
The researchers collected rat embryo structures that had been genetically modified so they would not develop kidneys on their own.
The embryos were then injected with pluripotent stem cells from mice and implanted into rat wombs so they could be carried to term.
Pluripotent stem cells are a kind of “master” cell that can for people develop into any of the cells and tissue that make up the body.
The researchers found that the mice stem cells produced apparently functional kidneys in the rats.
But the same did when rat stem cells into similarly mice embryos. not hold were injected modified
“Rat stem cells did not readily differentiate into the two main types of cells needed for kidney formation,” said Masumi Hirabayashi, an associate professor at Japan’s National Institute for Physiological Sciences, who supervised the study.
Conversely, “mouse stem cells efficiently differentiated... forming the basic structures of a kidney”, he said.
The reason for the difference is still not entirely clear, but the researchers believe “environmental cues” inside the mice are likely to blame, rather than the stem cells or technique.
But even in the rat embryos, the technique was not without problems.
While the rats developed apparently functional kidneys, including with proper connections to the ureter – tubes that link the kidneys to the bladder – they died shortly after birth because they did not suckle properly.
Removing the genes that allow kidneys to develop in utero appears to have also removed their sense of smell, so the newborns failed to detect milk and died.
Hirabayashi said he was hopeful he would see human organs grown in animal hosts in his lifetime.
Their success was only a first step and ‘complex ethical issues’ remain