The world's first clinical trial of induced pluripotent stem cells (iPS cells) to regenerate chronic renal failure patients' kidneys inside their bodies will likely commence this year, conducted by a team including the Jikei University School of Medicine in Tokyo.
Chronic kidney failure is a decline in kidney function over months or years, and patients must eventually rely on dialysis to filter their blood. The number of kidney failure patients is rising worldwide, and the research team -- which also includes Meiji University and medical startup Bios -- is looking to conduct its clinical trials outside Japan.
The clinical trial plan calls for cultivating kidney precursor cells from iPS cells created using each patient's own tissue. The precursor cells will be injected into a kidney "bud" taken from a genetically altered pig fetus, which will then be transplanted into the patient. Theoretically, medication administered to the patient will slowly kill off the pig kidney precursor cells in the bud while the patient's iPS cell-derived cells regenerate, growing into a new organ over several weeks. Since the kidney is formed solely from the patient's own cells, it is hoped that immunosuppressants will be unnecessary when this method is used.
"As we confirm the technique's effectiveness and safety, we are also aiming to put it into practical use in Japan to reduce burdens on patients, such as cutting the frequency of dialysis treatments," commented team leader and Jikei medical school professor Takashi Yokoo.
The researchers have already produced kidney precursor cells from iPS cells derived from human chronic kidney failure patients. They have also successfully grown new rat kidneys inside the animals by planting rat kidney precursor cells into the kidney bud of a mouse fetus. The regenerated kidneys were also successfully attached to the animals' urinary tracts, allowing them to release urine as normal.
The team is considering starting applications to conduct clinical trials this year at medical institutions in countries where regenerative medicine and transplanting pig organs into humans are legal. With an eye on conducting trials in Japan as well, the researchers are planning experiments using monkeys, which are genetically quite close to humans.