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The Science Behind the Stem-Cell Debate


Let's try to explain some of the science behind the politics of stem cells, or rather turn to someone who can explain the science behind the politics. NPR's Joe Palca.

Joe, good morning.

JOE PALCA: Good morning, Steve.

INSKEEP: I think you've got the hardest job on the program this morning, explaining what these people are talking about. Can I start with a really basic question? Just remind us, what is a stem cell line?

PALCA: Well, that's a good question, actually. Let's start talking about embryonic stem cell lines, since that's what the fiery part of the debate is all about.

So an embryonic stem cell line is when you take a human embryo that's being created in a laboratory - using in vitro fertilization, typically - and you remove some cells from it at a very early stage, making it no longer capable of turning into a baby because you've now essentially destroyed it for those purposes; but you can take these cells from the embryo and get them to start growing. And they grow and they grow and they grow, and they become a colony of what's called embryonic stem cells. And they can keep making more copies of themselves and more copies and more copies, and that becomes a line of cells. And what you can do with that is you can essentially grow them forever.

And the beauty part that scientists say is that you can then, by giving them certain signals, get them to turn into any cell type in the body. So if you want them to become a nerve cell, you give them a certain set of chemicals and they become nerve cells. That's the theory, anyway. And it's those cells that you've derived from these embryonic stem cells that might be used for treating diseases.

INSKEEP: So we know what a stem cell line is or an embryonic stem cell line is. We know why people are interested in them - scientists and doctors and many other people. What is wrong with the embryonic stem cell lines that are already available for research? Because President Bush did allow some at the time that he restricted federal funding.

PALCA: Yes, that's the interesting part. President Bush said - when he took office, he put the whole plans for the federal government to fund the embryonic stem cell research on hold; he said, I want to think about this. But on August 9th, he said okay, I'm going to let funds be available for embryonic stem cell lines that were created before August 9th, 2001, which was the day he made his decision.

And so the reason that those cell lines are thought to be inadequate is, basically, it was only three years after the first reports of being able to do this at all. And, you know, like anything, the first attempts at doing it tend to be a little clunky. And so the cells, the first cells were grown with chemicals and various products along with them that made sense at the time because nobody knew really how to do it. But now, it's thought that they were done improperly and that it would make more sense to derive these in a different way. And so that's basically why the science has moved on even though the federal funding hasn't expanded.

INSKEEP: Now let's talk about alternatives here, try to understand them, anyway. Opponents of embryonic stem cell research who say that their religious beliefs, or other beliefs, lead them to say that this is a taking of the human life have promoted the use of adult stem cells for research. Are there real possibilities there?

PALCA: Oh, absolutely. I mean, they are 100 percent right. The only successful stem cell therapies that are currently in existence have been using adults themselves. These are bone stem cells that are derived from bone marrow. And I'm sure people heard of bone marrow transplants for curing various blood cancers and other blood diseases.

So yes, there is a tremendous amount of promise and potential for studying the so-called adult cells. The difference between these adult cells and the embryonic stem cells is that the adult cells are typically more limited, so that the cells you get from the bone marrow typically can only make more blood cells.

And if you have a skin stem cell, that can only make more skin cells, although there are some fluctuation around that that maybe they are more potent. But the point is that embryonic stem cells can make any cells.

So if you're having trouble finding a brain stem cell, for example, which people have a hard time finding - they're not very easy to get your hands on -if you have already embryonic stem cells, you could make brain cells. That's the difference.

INSKEEP: Basic explanation of what they are arguing about in Congress from NPR's Joe Palca. And Joe, before you go, one other quick question: Is this whole debate in Congress becoming less relevant because states like California are going ahead in spending billions of dollars of their own on this research?

PALCA: Well, you know, in a sense I suppose it is because that is a large chunk of change for research that California and New York and Connecticut and New Jersey and Massachusetts, I mean, a lot states are getting involved.

But I think the problem is that you don't want to organize a national campaign, a research campaign with every state doing its own thing so that California may be copying what's going on in New Jersey and it may be just a mess. And so it's easier to have central coordination.

INSKEEP: Joe, thanks very much.

PALCA: You're welcome.

INSKEEP: Very clear. NPR science correspondent Joe Palca. Transcript provided by NPR, Copyright NPR.

Joe Palca
Joe Palca is a science correspondent for NPR. Since joining NPR in 1992, Palca has covered a range of science topics — everything from biomedical research to astronomy. He is currently focused on the eponymous series, "Joe's Big Idea." Stories in the series explore the minds and motivations of scientists and inventors. Palca is also the founder of NPR Scicommers – A science communication collective.
Steve Inskeep
Steve Inskeep is a host of NPR's Morning Edition, as well as NPR's morning news podcast Up First.
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