July 21st, 2015
For the first time ever, a whole lab-grown kidney has been successfully transplanted into a rat, where it allowed the creature to process urine like a really kidney would—and it could someday save your life.
A team of researchers from the Massachusetts General Hospital in Boston took kidneys from donor rats and washed away the cells using chemicals, to leave behind the basic collagen structure which supports the organ. Then, they grew the organ back using a combination of human stem cells and rat kidney cells. New Scientists explains how they did it:
[T]he team placed the kidney scaffolds in glass chambers containing oxygen and nutrients, and attached tubes to the protruding ends of the renal artery, vein and ureter – through which urine normally exits the kidney. They recoated the insides of the blood vessels by flowing human stem cells through the tubes attached to the artery and vein. Through the ureter, they fed kidney cells from newborn rats, re-coating the labyrinthine tubules and ducts that make up the kidney’s urine filtration system.
After plenty of failed attempts, the team finally hit on the perfect set of conditions and cell types, and found that they were able to grown a new rat kidney—like the one shown above—in about two weeks. When transplanted into a rat, the lab-grown kidney was able to process urine, but only at about 10 percent of the efficiency of a real kidney. The results are published in Nature.
As you’d expect, the researchers are confident they can achieve more—and they better, because 10 percent efficiency might buy some time, but isn’t enough to live a normal life. But they have bigger hopes for the technique. Harald Ott, lead researcher of the team who undertook the work, explains:
“If this technology can be scaled to human-size grafts, patients suffering from renal failure, who are currently waiting for donor kidneys, could theoretically receive an organ grown on demand. In an ideal world, such grafts could be produced from patient-derived cells, enabling us to overcome both donor organ shortages and the need for long-term immunosuppression drugs.”
The next step is intermediate. They want to try it out with pigs, which are a far better model for humans than rats. In the meantime, though, the finding stands as a major landmark in its own right: many researchers didn’t expect a functioning, complex organ like a kidney to be grown in the lab for years. Transplant science just got very exciting.