Researchers have successfully implanted a lab-grown kidney into a rat.

Human beings are one step closer to creating lab-grown organs for other human beings. That little organ donor sticker you have on your state-issued ID may one day become irrelevant—that's the plan. In what is a major hurdle for regenerative medicine, Scientists at the Massachusetts General Hospital in Boston, led by Harald Ott, have successfully transplanted a functional lab-grown kidney into a rat.

To be fair, the process isn't quite as sci-fi as completely growing a new organ from scratch, but it's a big hurdle now overcome. Ott and his team actually took an existing kidney from a dead rat and washed it in a special detergent-like mixture to strip it of all its cells. Basically, this process left the researchers with a new foundation from which to build upon. "The biologists were left with a kidney scaffold that they used to create a bioengineered graft of the real thing," io9 explained.

When you think about the process, it's almost like taking an old vehicle and completely restoring it. By re-seeding the graft with epithelial and endothelial cells, researchers were able to foster functional tissue in an incubated chamber. The key aspect of the experience, io9 said, was a pressure gradient that Ott used to "ensure the right cells were growing in the right places." After around five days of incubation, the grafts were able to produce rudimentary urine—not quite the real thing, but close for experimentation purposes.

Once researchers felt the lab-grown kidneys were working properly, they then transplanted them into live rats, which continued to function as expected. "Based on this initial proof of principle, we hope that bioengineered kidneys will someday be able to fully replace kidney function just as donor kidneys do," Ott said.

Ott and his team hope to take the experiments results and apply them to larger animals, and eventually humans. While researchers still relied on older organs, the results still highlights an enormous step toward one day creating organs from a patient's own cells. "We're now investigating methods of deriving the necessary cell types from patient-derived cells and refining the cell-seeding and organ culture methods to handle human-sized organs," Ott said.

Research is still obviously ongoing, and Ott admits he and his team were only successful after much trial and error, including "quite a few kidneys" that blew up. Be that as it may, the team's research may one day help reduce the incredibly long list of people awaiting donated organs.