For the first time, Salk scientists have grown human stem cells into early-stage ureteric buds, kidney structures responsible for reabsorbing water after toxins have been filtered out. In the laboratory, the scientists used mouse embryonic kidney cells (seen in red in the above picture) to coax the human stem cells to grow into the nascent mushroom-shaped buds (blue and green). Their discovery is a major step in developing regenerative techniques for growing replacement human kidneys.
Scientists had created precursors of kidney cells using stem cells as recently as this past summer, but the Salk team was the first to coax human stem cells into forming three-dimensional cellular structures similar to those found in our kidneys.
"Attempts to differentiate human stem cells into renal cells have had limited success," says senior study author Juan Carlos Izpisua Belmonte, a professor in Salk's Gene Expression Laboratory and holder of the Roger Guillemin Chair. "We have developed a simple and efficient method that allows for the differentiation of human stem cells into well-organized 3D structures of the ureteric bud (UB), which later develops into the collecting duct system."