Scientists at Massachusetts General Hospital have built a functional engineered rat kidney, washed clean of its former cells and re-seeded with fresh ones, and transplanted it into a live rat. The engineered kidney can produce urine and expel it through a ureter, and it didn't produce any blood clots.
The fact that it actually worked -- it produced urine -- is a major breakthrough for tissue engineering, which faces probably its greatest challenge with the all-important kidney. The team also washed out a human and a pig kidney, although those weren't transplanted.
Cool! It's notoriously hard to accomplish this step! Often, you spend years or decades designing a tissue-forming process which makes organs that work great in a lab and not so great in an animal.
I hope this becomes successful. Dialysis is sucky.
For some reason I first read that last sentence as "The humans also..."