Scientists at the University of Manchester have developed human "mini kidneys" from human embryonic stem cells that they cultured and used in vivo in mice. Indeed, these mini kidneys can filter the blood to produce urine. "We are the first team to introduce these kidney cells in vivo and show that they can work," explained Professor Susan Kimber, who directed the studies. Up to this point, studies on artificial kidneys focused more on the growth of complete organs in vitro, and less on their function in vivo.
The structure developed by Professor Kimber's team "is not equivalent to a kidney" because it contains only a few hundred nephrons compared to a human kidney, which has millions. However, "it possesses all of the elements required for blood flow up to the point of leaving the urethra". In the future, these "mini kidneys" could be used in the treatment of kidney diseases for patients being treated with dialysis or transplantation but "it remains to be seen if these cells could develop and survive in a hostile, damaged, renal environment". Furthermore, the structures were implanted subcutaneously in mice but a connection to a major blood vessel would be required to generate a high blood flow, and to reliably filter and cleanse the blood and remove accumulated biological waste.
 Published in Stem Cell Reports
 Structural and functional unit of the kidney allowing urine formation
The Independent, Alex Mattews King (9/02/2018)