Researchers take a step closer to creating customized human kidneys

TOKYO: Researchers have reported that they have successfully developed functional kidneys in rats using only a few donor stem cells, a breakthrough that has important implications for human organ transplantation.

According to the study published in the journal Nature Communications, the kidney transplant is the only hope to find a satisfactory quality of life.

Still, many of these patients will never undergo a surgical transplant because of a chronic shortage of donor kidneys, said researchers at the National Institute of Physiological Sciences of Japan.

With only 95,000 patients on the waiting list of a donor kidney in the United States alone, demand far outstrips supply, they said. .

However, researchers have been working on ways to develop healthy organs outside the human body.

One of these methods, called complementation of the blastocyst, has already given promising results.

The researchers take blastocysts, clusters of cells formed several days after fertilization of eggs, in mutant animals lacking specific organs, and inject them with stem cells from a normal donor, not necessarily the same species.

The stem cells then differentiate to form the missing organ in the resulting animal.

The new organ retains the characteristics of the original stem cell donor and can therefore potentially be used in transplantation.

"We had previously used complementation of the blastocyst to generate rat pancreas in a mutant mouse pancreas," said Teppei Goto, lead author of the study.

"So we decided to investigate whether the method could be used to generate functional kidneys, which would have a much greater application in regenerative medicine because of the high demand for donors," Goto said.

Early attempts by researchers to grow rat kidneys in mice were unsuccessful because rat stem cells do not readily differentiate into two main types of cells required for kidney formation.

However, when the reverse scenario was attempted, mouse stem cells differentiated efficiently inside rat blastocysts, thus forming the basic structures of a kidney.

After implantation in pseudopregnant rats, complemented blastocysts became normal fetuses, the researchers said.

More than two-thirds of the newborn rats obtained contained a pair of kidneys derived from mouse stem cells.

Further screening showed that all kidneys were structurally intact and that at least half of them could potentially produce urine.

"Our results confirm that interspecific complementation of blastocysts is a viable method for kidney generation," said study author Masumi Hirabayashi.

"In the future, this approach could be used to generate organs derived from human stem cells in cattle, potentially extending the lifespan and improving the quality of life of millions of people around the world," Hirabayashi said. .