AsianScientist (Sep. 29, 2025) – Chronic kidney disease is a global public health problem, affecting about 10 percent of the world’s population. Today, an estimated 2.6 million patients rely on renal replacement therapy, through dialysis or kidney transplantation – a number projected to double by 2030.
To meet this growing need, scientists have turned to regenerative medicine. But building fully functional kidneys in the lab has remained elusive, largely because one crucial part of the urinary system has been missing: the ureter.
Now, scientists at Kumamoto University, Japan, have made a major breakthrough in regenerative medicine by successfully creating functional ureter tissue — organoids resembling the urinary tract — from pluripotent stem cells, which are a special type of stem cell that can develop into almost any cell type in the body.
Why it matters
This achievement brings researchers one step closer to developing transplantable kidneys capable of producing and expelling urine.
The ureter, a tube that carries urine from the kidneys to the bladder, has long been missing from lab-grown kidney models. Without it, kidney organoids cannot fully mimic how real kidneys work, creating a major hurdle for future transplants.
“This is the first time a ureteral structure has been built entirely from pluripotent stem cells,” said Ryuichi Nishinakamura, a professor at the Department of Kidney Development in the Institute of Molecular Embryology and Genetics at Kumamoto University, Japan.
“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,” said Nishinakamura, who led the study published in Nature Communications.
The team successfully created ureteral tissues from pluripotent stem cells by combining induced ureteral stromal progenitors—cells that form supportive tissue—with epithelial components, which make up the inner lining of the ureter. These were derived either from mouse embryos or from induced ureteral epithelial progenitors. These cells organized themselves into three-layered tubes that could contract like real ureters, with some even showing rhythmic movements similar to natural urine flow.
The researchers also used cells with TBX18 mutations to model genetic ureteral disorders. These showed faulty tissue development, providing a useful platform to study congenital urinary tract diseases.
Creating a kidney project
This achievement is part of the “Creating a Kidney: A global network to generate transplantable kidney organoid” project, funded by the Japan Society for the Promotion of Science, which brings together researchers worldwide to pursue the goal of building fully transplantable kidneys from stem cells. Kumamoto University serves as the core institution for this initiative, which is led by Professor Nishinakamura.
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Source: Kumamoto University, Japan ; Image: Freepik
The study can be found at: In vitro generation of a ureteral organoid from pluripotent stem cells
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