Can Kidneys Regenerate Themselves?

Organ failure kills thousands of people every year. While transplantation is the solution, it is not always viable. There is a global shortage of organs, and to cater to this, researchers are now trying to develop organs in labs or even 3D print them. One such organ is the kidney. But there is more to it. During a recent experiment, researchers discovered that this organ can actually regenerate itself.

Human beings are born with two kidneys, which filter about a half cup of blood every minute, removing wastes and extra water to make urine. It has long been thought that kidney cells didn't reproduce much once the organ was fully formed. However, a new study published in Cell Reports in May showed that kidneys regenerate and repair themselves throughout life.

"This research tells us that the kidney is in no way a static organ," said Benjamin Dekel, MD, PhD, a senior author of the paper and associate professor of pediatrics at Sackler, as well as head of the Pediatric Stem Cell Research Institute at the Sheba Medical Center in Israel. "The kidney, incredibly, rejuvenates itself and continues to generate specialized kidney cells all the time, " added Irving Weissman, MD, professor of pathology and of developmental biology and director of the Stanford Institute,who is the other senior author.

'Kidneys regenerate themselves like a tree'

The study was conducted on mice and shows that "the kidney regenerates itself like a tree". Instead of a single type of kidney stem cell that can replace any lost or damaged kidney tissue, slightly more specialised stem cells segments of the kidney give rise to new cells within each type of kidney tissue." It's like a tree with branches in which each branch takes care of its growth instead of being dependent on the trunk," Dekel said.

There is a special protein involved. The decision these cells make to grow is made through the activation of cellular pathways involving a protein called Wnt. Even though populations of kidney epithelial cells look the same, the most robust kidney-forming capacity can be traced back to precursor cells in which Wnt is activated and that can only grow into certain types of specialized kidney tissue,

The realization that Wnt signaling is responsible for the growth of new kidney tissue offers a therapeutic target to promote or restore the regenerative capacity of the kidneys," he said. "We may be able to turn on the Wnt pathway to generate new kidney-forming cells." This finding can prove to be particularly useful for scientists who grow kidney cells in the lab.

Is it A Viable Option?

Despite this path-breaking discovery, researchers say that it is not a viable option to grow a whole kidney in the lab. To grow a whole kidney in the laboratory would be complicated because we would need to orchestrate the activities of many different kinds of precursor cells using just the right stimuli," Dekel said. "It's not like the blood and immune system, which can be reconstituted from one type of stem cell," he said.