Photo/Illutration The Asahi Shimbun

A team of researchers at Kyoto University successfully produced kidney tissues from stem cells that can function within a living organism, a first in the medical world.

The scientists transplanted kidney tissue cells derived from human stem cells into rats suffering from kidney failure.

After the transplants, the rats' kidneys recovered, according to the results of the research team’s study, published in the U.S. science journal Biochemical and Biophysical Research Communications.

The researchers aim to put the method into practical use as a regenerative medicine for damaged kidneys in humans in a few years. 

“Mesenchymal stem cells can be taken from patients’ own bodies and transplanted repeatedly,” said team leader Toshihiko Machiguchi, a former research fellow at Kyoto University’s Institute for Frontier Life and Medical Sciences. “We aim to put the method into practical application within two to three years.”

The team cultured human mesenchymal stem cells to create three-dimensional kidney tissues. The stem cells, which can grow into any type of body tissue, were cultured in a small amount of gel.

The researchers injected some 200 million tissue cells, derived from the stem cells, into the kidneys of five rats each. The rats had been administered drugs to artificially induce kidney failure.

The researchers compared changes in the rats’ kidney functions with five rats with similarly damaged kidneys that did not receive stem cell transplants.

The rats that did not receive transplants saw an increase in their serum creatinine level, which indicates worsening kidney function. Those rats died around 10 weeks later. The serum creatinine level for the other rats stopped rising seven weeks after the transplant and they survived for 14 weeks or longer.

The researchers also confirmed that normal kidney tissues grew in the rats that received the transplant.

Some 340,000 people suffering from kidney failure, including chronic kidney disease, underwent dialysis in Japan as of the end of 2018, and the number is increasing every year, according to the Japanese Society for Dialysis Therapy.

Since patients must continue dialysis for the rest of their lives unless they receive organ transplants, hopes are high for putting new regenerative medicine applications into practice for kidneys.