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Stem Cell Milestone Revives Intense Ethical Debate


This is MORNING EDITION from NPR News. Good morning. I'm David Greene.


And I'm Steve Inskeep.

We're going to look closely this morning at a dramatic advance in science.

GREENE: And also its far-reaching implications. The advance involves embryonic stem cell research.

INSKEEP: Which scientists see as a route to dramatic advances in medical treatment. Researchers have now figured out how to make embryonic stem cells that carry a specific individual's DNA.

GREENE: They hope that achievement will eventually lead to treatments for diseases like Alzheimer's, Parkinson's and diabetes.

INSKEEP: Although critics fear it may also lead us closer to human cloning.

NPR's Rob Stein reports.

ROB STEIN, BYLINE: One of the great goals in modern medicine is to mass produce cells that can cure all sorts of terrible health problems. They won't fight germs. But where cells are dying, organs are malfunctioning, or tissues are being destroyed, they could be life-saving. What doctors have long wanted are new cells to replace the ones that are going bad.

Shoukhrat Mitalipov of the Oregon Health and Science University led the new research.

SHOUKHRAT MITALIPOV: There are a variety of diseases, many of them actually age related, that some cells or organs or tissues malfunction and that's what causes disease, so unfortunately our body's ability to regenerate new cells is very limited.

STEIN: We do have some cells that could help. Researchers have been experimenting with cells they call adult stem cells. They can be found in many places in our bodies, in our bone marrow, in our blood. They can be harvested and grown and are already being use to treat some diseases, including cancers like leukemia.

But many scientists think stem cells from embryos might work better - much better, because they are a very early type of a cell that can grow into any tissue in the body.

And now Mitalipov and his colleagues have figured out how to make embryonic stem cells that might be the best ones yet, because they can be made with a patient's own DNA.

MITALIPOV: So idea is to produce this kind of early embryonic cells but using our own cells so that the genetic information is our own, so that way when we transplant these cells back into patients, they will not reject it.

STEIN: Here's what they did. They took a human egg and removed the DNA. Then they replaced those genes with the DNA from a skin cell of a patient. Then they found a new way to make the egg develop into an embryo. And when the embryo got to be about five days old, the researchers started removing individual cells.

MITALIPOV: And after a few days we could actually develop them in a Petri dish into stem cells. These cells have all this capacity to differentiate into a variety of tissues.

STEIN: In fact, Mitalipov even grew heart cells that could beat in the Petri dish. Other researchers are hailing the advance as a major development. George Daley is a stem cell scientist at Harvard.

DR. GEORGE DALEY: And I think it's a huge deal. I mean this is a real technical landmark.

STEIN: A landmark because scientists can now start to use them for treatment and basic research. For one thing, Sean Morrison of the University of Texas Southwestern Medical Center says, many researchers will want to turn the cells into miniature laboratories to study the basic biology of many diseases. For example, Morrison says, when a disease is caused by a genetic defect, they could make stem cells with those bad genes in them and figure out what's going wrong.

SEAN MORRISON: So they can better study the diseases in the laboratory dish and look for ways of curing it.

STEIN: And there's something else scientists can do now. They can compare embryonic stem cells directly to another kind of cell that some researchers think may actually be better. They're called iPS cells, and they're much easier to make than embryonic stem cells just by genetically reprogramming any adult cell.

MORRISON: Even though the reprogrammed adult cells and the embryonic stem cells seem amazingly similar to each other, it's still possible that their properties differ in certain subtle ways that will make one cell more suitable for certain kinds of applications than the other.

STEIN: But there's a lot about what the Oregon researchers did that's controversial. For one thing, they created and then destroyed human embryos - which for some people, like Richard Doerflinger of the U.S. Conference of Catholic Bishops, is morally unacceptable.

RICHARD DOERFLINGER: There is something that has that extra level of cold-bloodedness, if you will, about making these lives in the laboratory, whatever you think they are. I mean I'd say they're human beings and they have a right to live.

STEIN: But perhaps even more disturbing to more people, there's a chance the Oregon team's techniques could be used to try to create a baby that's a clone.

DOERFLINGER: If this procedure is successful for creating embryos for research, it is almost certainly equally successful in creating embryos that can be put in a womb to make a cloned child. This hastens the day when we are talking about whether we clone our children as well.

STEIN: Now, the Oregon scientists disagree. They say their experiments with monkeys and other animals indicate it's very unlikely their techniques will ever work to clone a person. Rob Stein, NPR News. Transcript provided by NPR, Copyright NPR.

Rob Stein is a correspondent and senior editor on NPR's science desk.