Embryonic Stem Cells Made Without Embryos
JOHN YDSTIE, host:
The debate over research on human embryonic stem cells has taken a dramatic turn. Two research teams have independently shown that it's possible to make cells with all the properties of embryonic stem cells without destroying a human embryo. That would remove the moral objections somehow to this research. It also means it might not be necessary to use cloning techniques to tailor stem cells to individual patients.
NPR science correspondent Joe Palca is covering this story and joins us now.
Joe, let's start with cloning. How does this new research eliminate the need for, what some call, therapeutic cloning?
JOE PALCA: Okay, so here's how this works. Let's say we want to make - take a skin cell from you, John Ydstie, and turn it into an embryonic stem cell so that it has the potential someday to turn into any cell in your body. So if you need a new brain cell or a new insulin-piercing cell, we've got a whole stock of them. They're sitting in a lab some place ready to be re-implanted into you. And since they're yours, you're not going to reject them. They're fine.
So how do you get a skin cell to turn back into an embryonic stem cell because a skin cell's DNA, even though it has all the instructions for you in it, the cell is programmed to be a skin cell. Well, what Scottish scientists found when they made Dolly is that you can take this skin cell or adult cell and put it into an egg, from which you've removed the nucleus, and something in the egg reprograms the DNA of that skin cell and returns it to a state where it could be an embryonic cell. Okay?
Now, that was what was called therapeutic cloning. We take a cell from you, put into an egg from what's the nucleus moved and -what this breakthrough is, is that the scientists from Japan and the United States have found four genes that if they put those four genes into a skin cell, it does the same thing the egg does. It turns that skin cell back. It reprograms the DNA so that it can be an embryonic cell. It's not using an embryo anymore so the nomenclature gets funny, but it has all the properties of an embryonic stem cell. That's what the research is.
YDSTIE: Mm-hmm. Now, I understand at least one prominent researcher says he's planning to abandon his research on cloning as a technique for getting patient-specific embryonic stem cells. Are other scientists going to follow suit?
PALCA: Well, that's right.
YDSTIE: Are they going to abandon this?
PALCA: Well, Ian Wilmut, the scientist who was leading the team that created Dolly, says I'm so convinced that this new technique is superior. He was planning to try to do cloning with human cells, and he said I'm not. But I've talked to a lot of researchers in this country who say, wait a minute, everything looks good but these are the first two papers on this topic. There may be problems we haven't anticipated. We're pretty sure we've shown on animals. There was just the story last week in primates and monkeys. We can do this, so we shouldn't drop this now. It's too soon. We have to keep both paths going until we're sure that this new technique is equivalent to what we think works in cloning.
YDSTIE: Well, that raises the question: So does this new technique really eliminate the ethical problems of research on stem cells?
PALCA: Well, in the long run, I think it does. I really think that the people who have raised objection to embryonic stem cells because of embryos are now saying if we can do this another way, we told you there would be other ways. We should have waited and found these ways and then we wouldn't have had to destroy any embryos. But for the short run, as I say, I think that the scientists are still saying we need to study these embryos as well because, you know, we just don't know at this point.
YDSTIE: So this is all aimed at therapies actually. What are the hurdles still to overcome before these cells made using these techniques can be used in therapies?
PALCA: Well, there's two kinds of hurdles really. One is the hurdle facing any kind of stem cell embryonic base — stem cell base research is right now nobody's gotten one to work in a human patient. There are some models that are promising, but there's still lot of things. It's not just the question of squiring the cells in and letting them do their thing.
Then the other issue, which is just specific to these new cells, is that the way they were created using these four genes could have problems of its own. In fact, one of the genes that the Japanese team used is a kind of a cancer-causing gene. You don't exactly want to use that. Plus, the way they get these genes into cells could cause problems. So there's still a shorter-term problem as well as the big problem.
YDSTIE: NPR science correspondent Joe Palca, thanks very much.
The first embryonic stem cells were isolated in mice in 1981. You can track the history of stem cell research and controversies at npr.org.
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