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Bioengineered Rat Kidney Produces Urine

Kayt Sukel

For the first time, a bioengineered kidney that can produce urine when transplanted into a rat has been reported. How well does it compare to normal kidneys? Find out...

One new name is added to the national transplant waiting list every 11 minutes, according to the National Network of Organ Donors. Most of these individuals will wait months, even years, for a viable donor organ, and far too many won’t survive the wait.

For the first time, a bioengineered rat kidney that can produce urine when transplanted into rats has been reported. Source: Massachusetts General Hospital Center for Regenerative Medicine

But now, researchers at Massachusetts General Hospital’s Center for Regenerative Medicine have bioengineered a rat kidney that can produce urine after transplantation into a living animal, providing further proof that bioengineered organs may be a realistic treatment option in the future.

One of the biggest challenges of bioengineering organs has been creating the appropriate scaffold material that provides support for the cells and directs tissue organization and cellular function.. “Instead of trying to grow a new structure from scratch to provide that scaffold material, we found a way to isolate the scaffold that is already in the native organ,” said Harald Ott, a surgeon at the Center for Regenerative Medicine. “That allows us to provide the geometrical context for whatever you need to generate organ function.”

Ott proved this particular approach when he was a research fellow at the University of Minnesota by removing the cells from rat kidneys using a detergent compound that leaves the organ’s collagen scaffold intact. “Because the scaffold maintains the normal architecture of the organ, we repopulate new cells and are able to see those cells organize into the right compartments they belong in,” he said.

The trick, however, was in demonstrating that this bioengineered organ was functional. In a paper published this week in Nature Medicine (1), Ott and colleagues report that their bioengineered rat kidneys produced a small amount of urine in a specialized device that mimics passing blood through a vascular system.

The group then transplanted the bioengineered organs into living rats. Again, the bioengineered kidneys were able to produce a small amount of urine, suggesting that these organs were filtering blood—without side effects such as bleeding or clots.

While the bioengineered kidneys did not show the same level of function as normal, healthy kidneys, Ott argues that this technique holds promise for the future—one in which researchers can build a viable new kidney, heart, or lung from the cells of individuals suffering from organ failure.

“In an ideal world, eventually, you could grow an organ on demand with a person’s own cells. In an ideal world, you could grow an organ where rejection after transplantation will not be a problem,” he says.

The results are quite promising but still preliminary. Ott hopes that with this success he can join with new collaborators to help him refine the process, providing insights that will allow the repopulation of organ scaffolds with the right cells for optimal function.

“The next big step is to work on the cells themselves and derive the right building blocks required to build healthy, functional organs,” he says. “Once we do that, we can think about moving this technology up to the human scale.”


1. Song, J. J., J. P. Guyette, S. E. Gilpin, G. Gonzalez, J. P. Vacanti, and H. C. Ott. 2013. Regeneration and experimental orthotopic transplantation of a bioengineered kidney. Nat Med advance online publication(April).

Keywords:  bioengineering