Scientists Explore New Route for Creating Stem Cells

If successful, the technique could sidestep controversy over embryonic stem cell research

MONDAY, Aug. 22, 2005 (HealthDayNews) -- Harvard researchers say they've discovered a way to combine embryonic stem cells with human skin cells, which were then reprogrammed to become embryonic cells.

While it's too early to know the clinical implications of this discovery, the researchers hope that turning adult cells back to their embryonic state would offer new therapeutic possibilities while sidestepping the political concerns of using embryonic stem cells.

The report appears Aug. 22 in the early online release of the journal Science.

"The long-term goal of these experiments is to make embryonic stem cells," said researcher Kevin Carl Eggan, an assistant professor of molecular and cellular biology at Harvard University. "The advantage is that one can make an embryonic stem cell line that carries the particular genes of the patient. This can be used to treat that patient without the potential for rejection."

However, any therapeutic use of the new technology is at least a decade way, he said.

Embryonic stem cells have the potential to become any type of cell in the body. But because they come from human embryos, their use in medicine is controversial, pitting science against those who believe that using these cells destroys human life.

Researchers believe embryonic stem cells could be used for treatments for diseases such as diabetes, liver failure, spinal injury, stroke and heart disease, Alzheimer's disease and multiple sclerosis.

In its experiments, Eggan's team merged human embryonic stem cells with human skin cells. This combination produced hybrid cells that contained DNA from both the skin cell and stem cell chromosomes. These hybrid cells looked like, grew like, and had key genetic characteristics of human embryonic cells.

Moreover, they acted like embryonic cells and were able to become cells from each of the three main tissue types that form in a developing embryo, Eggan's team found.

The problem with using these newly created embryonic stem cells for therapeutic treatment is that they contain DNA from both the original embryonic stem cell and the adult skin cell. It's not yet certain if removing the embryonic stem cell DNA would cause the skin cell to revert to an adult cell, the researchers said.

Eggan hopes these experiments will lead to a new way of creating embryonic stem cells. "If one could simply understand how that process of reprogramming works, one might be able to directly turn adult cells into embryonic stem cells without an egg or an embryo," he said. "This is the first step on a long and uncertain road to do just that," he added.

Eggan noted that these experiments aren't designed to replace other research into embryonic stem cells.

"This technology is not ready for prime time right now," he said. "This does not replace technology we know to work. In the future it might be possible to use this as an alternative."

Eggan believes it will take at least 10 years before this method might have a role in treating disease.

One expert believes these early results are exciting and worth pursuing.

"This follows up on some work that has been done," said Dr. Diane Krause, an associate professor of laboratory medicine at Yale University. "It's not ready for therapeutic application, but it's a wonderful piece of work."

"I don't know if this will lead to a way of directly cloning embryonic stem cells," Krause said. "But they [researchers] are going to learn a lot about cell reprogramming and what changes need to go on to make a cell be like an embryonic stem cell."

Krause believes that if embryonic stem cells could be created from adult cells, it would defuse the political and ethical debate surrounding embryonic stem cell research. "It would prevent the need for using an unfertilized egg in making a new embryonic stem cell line," she said.

More information

The National Institutes of Health can tell you more about stem cells.

SOURCES: Kevin Carl Eggan, Ph.D., assistant professor, molecular and cellular biology, Harvard University, Cambridge, Mass.; Diane Krause, M.D., Ph.D., associate professor, laboratory medicine, Yale University, New Haven, Conn.; Aug. 22, 2005, early release, Science
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