Scientists at Massachusetts General Hospital say they have successfully "grown" a kidney in a laboratory environment and transplanted it back into a healthy animal, raising the tantalizing possibility of a future with organs grown in lab dishes—and a potential end to donor shortages. So far, the technique has only been used on rats, but with more time and practice, it could be scaled up to pigs, then humans, and possibly even other organs, like livers and hearts. The study was published in the journal Nature Medicine this week.
Here's how it works: The researchers took an existing kidney out of a rat and stripped it of all its old cells, leaving behind a "scaffold," that is just strands of cellulose and protein making up the frame of a kidney. (This framework also includes the kidney's blood vessels and connecting structures.) Doctors then pumped a compound, including stem cells from young rats, back into the structure and over the course of a couple of weeks, the cells attached themselves to the scaffold, differentiated into the various components of the organ, and re-grew to form the rest of the kidney. Once transplanted back into a rat, it functioned like a regular kidney, creating urine and filtering waste—though not as efficiently as a healthy one can. The process still needs some refinement to improve the quality of the new organ.