These cells are then known as endodermal progenitor cells, and they have nearly unlimited growth potential in the lab, according to the authors.
But, delaying the cells at the endodermal stage does limit the type of cell they can later become. Endodermal progenitor cells can only become cells found in the digestive tract, such as intestinal, liver or pancreatic cells, and possibly lung cells, Gadue said.
It's as if the initial stem cells are college freshmen undecided about what course of study they want to pursue. At this point, they can essentially choose any career. For stem cells, that means some choose to become tumors.
However, Gadue and his colleagues found a way to guide the cells to the school of study that might be right for them, such as a school of engineering or a school of art. And, for stem cells, that means the choice no longer includes becoming a teratoma. But, that also means that the cells' pathways are more limited, like an engineering major who chooses a subspecialty of mechanical engineering, but can no longer choose art.
Of course, while creating a stem cell line that doesn't produce teratomas is important, it's also important that cells in that line grow up (differentiate) to become other cells. And Gadue's team was able to create pancreatic beta cells that could produce some insulin. Beta cells are the cells that are damaged or destroyed in people with diabetes.
The investigators found that in the lab, the newly created beta cells produced insulin after being exposed to glucose (sugar), a function that is absent or impaired in people with diabetes. However, the cells didn't achieve full function, producing only about 20 percent of the expected insulin.
Juan Dominguez-Bendala, director of stem cell development for translation research at the Diabetes Research Institute in Hollywood, Fla., said that the 20 percent function isn't much different than what's been seen in other studies, and
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