MICHELE NORRIS: From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.
MELISSA BLOCK: And I'm Melissa Block.
The world of stem cell research is about to be turned on its head. Today, two independent teams of scientists said they have come up with a way to make stem cells that does not involve starting with human eggs or embryos. If the work holds true to its initial promise, not only will ethical issues be resolved, but scientists will easily be able to tailor stem cells to special patients.
In a few minutes, we'll hear how some key people in the debate over embryonic stem cell research are reacting to this news.
First, here's NPR's Joe Palca with more on the studies.
JOE PALCA: Just over a year ago, a scientist from Kyoto University presented data that electrified a group of stem cell researchers meeting in Toronto. Shinya Yamanaka announced he had found a cocktail of four genetic factors that could make a regular old mouse skin cell behave like a mouse embryonic stem cell. The implications were enormous.
If the same technique worked in humans, it would mean you no longer needed eggs and embryos to make embryonic stem cells. So Yamanaka began experimenting with human cells.
SHINYA YAMANAKA: We started working on human cells more than a year ago. But in the beginning the four factors did not work.
PALCA: But Yamanaka and his colleagues kept at it. And as they report in the current issue of the journal Cell, they finally got the technique to work. Yamanaka says it's not certain the new cells are exactly the same as stem cells from human embryos.
YAMANAKA: We studied various aspects of those cells and all I can say is they are very similar.
PALCA: At the same time Yamanaka was working in Kyoto, James Thomson of the University of Wisconsin in Madison was also looking for genes that would turn ordinary human cells into cells with all of the potential of embryonic stem cells.
In the current issue of the journal Science, Thomson reports he also found four genes that can work this transformation, and there maybe others, too.
JAMES THOMSON: We ended up with slightly different outcomes. And two of the genes happen to be the same and two are different. So it does seem that there's multiple pass to the same outcome and how divergent those pass are really remains to be seen.
PALCA: In the experiments Thomson is publishing today, he used two kinds of skin cells, one isolated from a human fetus and another from a newborn foreskin. But he says the technique works on adult cells as well and that's what makes this such a big step forward.
THOMSON: I think in some sense it changes everything and in some sense it changes absolutely nothing. It changes everything and that these are not cells derived for embryos anymore. And it remains to be seen if these are perfectly the same as embryonic stem cells but my feeling is that, overtime, we will get better at it and it will essentially equivalent to embryonic stem cells. And that very much changes the ethical debate.
PALCA: Because embryos no longer need to be destroyed.
THOMSON: What I mean that it doesn't change anything is that we're back at the same starting point now. These, biologically, are - just appear to be the same as embryonic stem cells. And we're still out to figure out how to differentiate them to useful things.
PALCA: That is to change them into useful cells for therapies. The whole idea of stem cell-based therapies is that stem cells could be used to replace or repair cells damaged or destroyed by disease of injury. New heart cells for people who've had heart attacks or new neurons for patients with Alzheimer's.
Jose Cibelli is a stem cell researcher at Michigan State University in East Lansing.
JOSE CIBELLI: This is a huge deal. We no longer have to rely on eggs. Anybody can do this procedure. It's a very simple recipe. It's a combination of three or four genes and a couple of weeks you go from a skin cell to an embryonic stem cell. It's a remarkable.
PALCA: As remarkable as the new results are, there are still some significant hurdles to overcome.
Leon Zon is a stem cell researcher at Children's Hospital in Boston. He says one of the genes Yamanaka used can cause cancer. And on top of that, Zon says to get their four genes into skin cells Yamanaka and Thomson used viruses that could be dangerous.
LEON ZON: The important aspects of the work in the future is to get rid of this using viruses and putting them into cells, but to find other ways, perhaps chemicals or other strategies to change the skin cells into embryonic stem cells.
PALCA: Zon is confident that will be possible.
There's an interesting coincidence here. James Thomson was the first scientist in the world who derived human embryonic stem cells from human embryos in 1998. Now, he is the first with a kind of stem cell that may make that achievement obsolete.
Joe Palca, NPR News, Washington.
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