The two teams, conducting parallel research in different parts of the world, announced their research this week in papers published in the journals Cell and Science.
Both teams did essentially the same thing, reprogrammed the skin cells to begin behaving like embryonic stem cells. Called pluripotent cells, the stem cells can be coaxed to grow into any cell in the body.
James Thomson of the University of Wisconsin is co-author of the U.S. paper published in Science. Thomson notes it's been about ten years since researchers derived the first stem cell lines which ignited the controversy that has continued up until today.
"And I believe these new results while they don't eliminate that controversy, is probably the beginning of the end of that controversy, because I think more and more labs will pursue a reprogramming path to get pluripotent cells rather than deriving them from embryos."
Thomson believes over time, more and more labs will be moving away from embryonic stem cell research in favor of the reprogramming of ordinary cells.
There's been strong opposition to embryonic stem cell research because the embryo must be destroyed. In the journal Cell, Shinya Yamanaka and colleagues at Kyoto University report they created nerve and heart cells out of reprogrammed stem cells.
Yamanaka says the researchers found they were able to coax the newly created stem cells to produce a range of other tissue cells.
"For example, we were able to make muscle and fat tissue, and so on. So, we were able to make many types of cells in addition to neuron and heart cells."
Much has been made about how stem cells could be used to create tailor made organs for individuals with disease and eliminate problems with the body's rejection of transplants and other therapies. While Thomson says that is true, he says the really big challenges are not solved by making stem cells from ordinary skin cells.
"The thing that's hard, is understanding the disease you are trying to cure, and putting cells in the body in a way that actually corrects the disease and allows function to be reestablished. And these cells don't differ from embryonic stem cells in that basic problem."
Researchers say they have much to learn about the reprogrammed stem cells before they could possibly be available for human trials. One concern is that they might lead to cancer because of the process used to manipulate the skin cells involves changes in their DNA.
But experts believe it's a matter of time before that issue can be worked out and the reprogramming technique will lead to an acceleration of research in this area.