Scientists at Kumamoto University have successfully created functional ureter tissue, organoids resembling the urinary tract, from pluripotent stem cells. This achievement brings researchers a step closer to developing transplantable kidneys capable of producing and expelling urine.
The ureter is a tube that carries urine from the kidneys to the bladder. Without the ureter, kidney organoids could not simulate complete organ function, which poses a major obstacle to future transplant applications. Over the years, scientists have tried and failed to replicate the ureter in lab-grown kidney models.
A research group from the Institute of Molecular Embryology and Genetics at Kumamoto University successfully developed ureteral tissues from pluripotent stem cells. Their method integrated induced ureteral stromal progenitors and epithelial components derived from mouse embryos or induced ureteral epithelial progenitors.
Once these cell types were combined, they self-assembled into three-layered, peristaltically contracting ureteral structures. The researchers also reported that some organoids displayed rhythmic contractions similar to natural urine flow. Furthermore, the researchers modelled genetic ureteral disorders using cells with TBX18, which resulted in impaired tissue development; this offers a useful platform for congenital urinary tract diseases.
Professor Ryuichi Nishinakamura, the lead author of the study, commented: “This is the first time a ureteral structure has been built entirely from pluripotent stem cells,” he continued, “Combining this with our kidney organoids may enable the construction of transplantable kidneys that can produce and excrete urine, marking a significant step toward next-generation regenerative therapies.”
