The number of patients who require kidney transplantation or dialysis therapy due to renal failure is increasing. As of 2013, more than 31 patients in Japan alone are receiving dialysis therapy, and 3 new patients are introducing dialysis therapy every year.The cost is 8000 million yen per person, totaling more than 500 trillion yen, which is a major factor in the increase in medical expenses in the country.On the other hand, due to the shortage of donors for kidney transplantation, the actual situation is about 1 cases per year.Realization of kidney regeneration is required to cope with such a situation.Previous studies have succeeded in regenerating a bladdered kidney made from human-derived stem cells in the rat body.Although it was possible to actually make urine, there was no route to excrete urine, so there was a problem that it fell into a state of hydronephrosis and could not continue to grow.

　Therefore, Professor Yokoo and his colleagues thought that continuous growth would be possible if the urinary tract could be constructed.First, the pre-growth kidney with a bladder transplanted to the rat is developed.By connecting the ureter that the rat originally had to the bladder by a surgical method, it was confirmed that urine was excreted normally.We also showed that the same method can be applied to cloned pigs.

　In the future, we aim to build a urinary excretion route in the regenerated kidney with primate marmosets that are closer to humans.In addition, since we have not succeeded in making all the ureters and urinary bladder of new kidneys from human-derived cells, we are also working on the development of a method for suppressing rejection after transplantation.Further research in the future will enable patients with renal failure to regain a healthy life.

Source:[Keio University] Succeeded in excretion of urine from regenerated kidney-a big step toward clinical application-