A new update in regenerative medicine from researchers at Kumamoto University in Japan has revealed that functional ureter tissue has been successfully engineered from pluripotent stem cells
This new advancement brings scientists closer to the goal of developing fully transplanted kidneys capable of both producing and expelling urine, which has always been a struggle in the field of organ research.
Lab-grown kidneys
The ureter plays a crucial role in the human urinary system, acting as the passage through which urine flows from the kidneys to the bladder.
Although some scientists have made progress in creating kidney organoids, these models have lacked a functional ureter. Without it, even the most advanced kidney organoids could not simulate full organ function, limiting their potential for use in transplantation or disease modelling.
The Kumamoto University team, led by Professor Ryuichi Nishinakamura from the Institute of Molecular Embryology and Genetics, has now addressed this gap. By generating ureter tissue that mimics the structure and function of the real organ, they’ve opened new doors for the development of transplantable kidney systems.
Engineering the ureter from stem cells
The scientists used pluripotent stem cells, which can develop into any cell type in the body, to generate the ureter tissue. Their approach involved integrating two key components: ureteral stromal progenitors and epithelial cells. These were derived either from mouse embryos or induced from stem cells to form ureteral epithelial progenitors.
When combined, these cell types self-organised into three-layered structures that resembled natural ureters. Some of these lab-grown structures exhibited rhythmic, wave-like contractions, closely mimicking the natural peristaltic motion that facilitates the passage of urine through the ureter.
This feature not only demonstrates the functional capability of the engineered tissue but also highlights the potential for creating complete urinary systems in the laboratory. This goal has long been a target of regenerative medicine researchers.
A new tool for studying disease
In addition to organ development, the engineered ureter tissue also provides a new platform for studying genetic and congenital disorders. The researchers modelled a genetic condition involving mutations in the TBX18 gene, which is known to affect ureter development. Organoids with this mutation showed impaired tissue formation, allowing scientists to observe and analyse the developmental disruptions in a controlled environment.
This disease modelling capability makes the new ureter organoids a valuable tool not just for transplant science, but also for understanding the mechanisms behind congenital urinary tract disorders and potentially testing treatments.
The future of transplantable organs
This achievement is part of a larger initiative titled “International Leading Research: Creating A Kidney,” an ambitious project funded by the Japan Society for the Promotion of Science (JSPS). The project aims to build fully functional, transplantable kidney organoids and is centred at Kumamoto University, with collaboration from a global network of scientists.
By combining the new ureter tissue with previously developed kidney organoids, researchers are moving closer to constructing artificial kidneys that can perform all the functions of their natural counterparts, including urine production and excretion.
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