08 Feb 2019
Researchers get one step closer in creating made-to-order human kidneys
For patients undergoing the last stage of renal disease, kidney transplant is the only hope for going back to a normal life.
And, considering how patients outnumber the donors, the situation is often grave.
However, scientists in Japan have recently announced that they have successfully grown kidneys in rat embryos, using a technique that could someday help grow human kidneys for transplant.
Researchers injected rat blastocysts with mice pluripotent stem cells
The method is called blastocyst complementation.
Researchers from the National Institute for Physiological Sciences took blastocysts, clusters of cells formed several days after egg fertilization, from genetically modified rats who couldn't develop kidneys on their own.
The blastocysts were then injected with pluripotent stem cells from mice.
Pluripotent stem cells can develop into any of the cells and tissues that make up the body.
Mice stem cells differentiated and produced functional kidneys in rats
The mix is then implanted into rat wombs, which serve as a host to where the kidneys will be grown.
It was found that the mice stem cells differentiated and produced functional kidneys in the rats.
The new organs produced retain the characteristics of the original stem donor (in this case, mice).
Therefore, this technique can be used in transplantation therapy.
At least half of the kidneys could produce urine
Researchers revealed that, later, the complemented blastocysts matured into normal fetuses.
Also, over two-thirds of the rat neonates in the research contained a pair of kidneys derived from the mouse stem cells.
Moreover, all of the kidneys were structurally intact and at least half could produce urine.
This confirmed the researchers that interspecific blastocyst complementation is a viable method for kidney generation.
Blastocyst complementation used previously to generate pancreas in mice
Teppi Goto, the lead authority of the study, told media, "We previously used blastocyst complementation to generate rat pancreas in a pancreatic mutant mice."
"We, therefore, decided to investigate whether the method could be used to generate functional kidneys, which would have much greater application in regenerative medicine owing to the high-donor demand," he said.
The research was published in the Nature Communications Journal.
'Approach could be used to generate human stem cell-derived organs'
"In the future, this approach could be used to generate human stem cell-derived organs in livestock, potentially extending the lifespan and improving the quality of life of millions of people worldwide," Masumi Hirabayashi, a corresponding author of the study, said.
Mice stem-cells can produce kidneys in rats, not vice versa
Initially, researchers tried growing rat kidneys in mice but it wasn't successful, as rat stem cells didn't readily differentiate into the two main types of cells needed for kidney formation.
For the uninitiated, the easy difference between a mouse and a rat can be detected by their size.
Mice measure around 12-20 cm, while rats are bigger and may grow as long as 40cm.