Using stem cells from a mouse embryo, Japanese scientists say they have generated functioning kidneys in three mice, an advance applauded by American scientists who see the development as a significant step toward stem cell-derived kidneys for humans. Hiromitsu Nakauchi of the University of Tokyo presented his studies on Monday in Australia at the International Society for Stem Cell Research. Mouse embryos engineered to lack a critical gene needed to grow their own kidneys were injected with stem cells before implantation into surrogate mothers. When the mice were born, they had functioning kidneys, Nakauchi told the meeting. Only one mouse had minor abnormalities. Stem cell-derived kidneys for humans are still at least a decade away, researchers said. Scientists in the field of regenerative medicine have been struggling to produce “off-the-shelf” organs and other body parts for people who’ve lost vital tissues. New organs coaxed from stem cells are a genuine possibility, scientists say.“This is terrific science,” said Dr Ronald Crystal, who chairs the department of genetic medicine at Weill Cornell Medical Center in Manhattan. “All of the things coming out about stem cells are exciting, but there are several caveats, and the biggest one is that humans are not big mice.” Nakauchi’s report is yet to be published in a peer-reviewed journal. Data released reveal the kidneys look like the twin bean-shaped organs. They are said to possess nephrons, the basic units within kidneys that regulate water and soluble substances by filtering blood and excreting urine. “Just how exciting this is depends on the kind of stem cells they used,” said Dr Alan Russell, University of Pittsburgh. Because mouse stem cells were involved, that means kidneys can be generated in specially bred mice. The real test, Russell said, is producing kidneys from human-derived stem cells.
