Functioning human, pig kidneys grown in mice By Judy Seigal   23 December 2002

Researcers at the Weizmann Institute have managed to grow functional miniature human kidneys in a mouse, opening up the possibility of creating an unlimited supply of such organs for transplanting in human kidney-disease patients.  Details about the achievement have been published in Monday’s issue of Nature Medicine.

            Instead of searching for a kidney donor, said team head Prof. Yair Reisner of the Weizmann Institute’s immunology department, one may be able eventually to grow a new kidney.  The team induced human stem cell tissue to grow into functional kidneys and have accomplished the same with stem cell tissue taken from pigs.

            The procedure is now in the pre-clinical study phase, said Reisner, but if all goes well, it could be applied in human kidney transplantation within a few years.

            The team – which included scientists from Sheba Hospital at Tel Hashomer and Hebrew University computer scientists and engineers – said they used kidney precursor cells (stem cells destined to become kidney cells) taken at their earliest gestational point.  They thus differentiated into functional kidney cells and not into other cells types.  The miniature kidneys they produce released dilute urine.  The team also showed that the tiny kidneys caused less immune-system resistance in the recipient mice than adult kidney transplants.

            Prof. Michael Friedlaender, of the Hadassah-University Hospital’s department of nephrology and chief of its kidney transplant clinic, commented that he had not known of the work at Weizmann.  “If it has been done, I can only rejoice for my patients.  I want to read the Nature Magazine article.  We have longed for the time when we could go to an ‘orchard’ of kidneys and pluck those we needed and we seem to be getting closer to that time,” he said.

            “There are 600 people in Israel waiting for a kidney donation.  About half of kidney transplants involve an organ from a live relative donor.”

            There are still kidney failure patients living on dialysis because they are not suited to a transplant because they have other serious chronic diseases, he said.  But if there is a greater supply of kidneys thanks to stem cells, many people will be able to live onger and with a higher quality of life.

            The Weizmann finding suggest that human or pig fetal tissue might take on the shape and function of a healthy kidney if transplanted into humans as well.  The scientists hope that porcine stem cells might thus provide a source for those in need of a kidney.

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