Researchers Advance Cloning Of Human Embryos

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Researchers in New York are reporting an advance in creating cloned human embryos. The embryos would not be used for reproduction, but rather for the creation of embryonic stem cells. Many scientists believe that human embryonic stem cells made this way could revolutionize medicine.

The advantage of stem cells made this way is that they could be personalized to an individual.

[Egli's work] isn't the gold ring, but it's a major step forward.

- George Daley, stem-cell researcher, Children's Hospital Boston

Think of it this way: Let's say you know you're going in for surgery in a few months to have your hip replaced. The surgeon says you may lose blood during the surgery, and recommends that you donate a pint of your own blood in advance in case you need it during the operation.

The advantage of donating your own blood is that there's no chance your immune system will reject that blood if it's put back into you.

Cloning, or somatic cell nuclear transfer, as scientists prefer to call it, is a technique that allows you to make what is essentially a genetic copy of a living organism. Stem cells derived from a cloned embryo are made with one of your stem cells but will be genetic twins to all the cells in your body, so receiving a stem-cell transplant would essentially mean getting your own cells back.

Dieter Egli and his colleagues at the New York Stem Cell Foundation have taken an important step toward that goal.

First they took an egg, removed its genetic material, replaced it with the genetic material from an adult skin cell, and coaxed the resulting embryo to grow. This is basically the same technique Scottish scientists used to create the first cloned mammal, Dolly the sheep. (See the top path in the illustration below.)

But Egli says that just because something works in some mammals doesn't mean it necessarily has to translate to human cells. And as others have found in the past, embryos made this way wouldn't grow.

Then Egli modified the Dolly technique. He left in the egg's genetic material instead of removing it, and then added the genetic material from the adult cell. That did the trick. The embryo started growing. (See the bottom path in the illustration below.)

Nature

In a first attempt (top), researchers removed an egg's genetic material and replaced it with the genes from an adult skin cell. These embryos didn't grow. The researchers tried another method: They left the egg's original genetic material in, but then also added genetic material from an adult cell (bottom). These embryos started growing.

But there was a problem.

Leaving in the egg's DNA meant each cell in the embryo now had three sets of chromosomes, instead of the two that are normally there. Transplanting stem cells derived from these embryos as a medical therapy wouldn't work. Our bodies just wouldn't know what to do with three sets of chromosomes.

Nature

This image shows the chromosomes from one of the cloned cells. Notice there are three sets of each chromosome; normal cells have just two copies of each chromosome.

But at least Egli has answered the question of whether it's possible to make a cloned human embryo. "The clear answer of our paper to this is yes, and this is really the major finding of the paper," he says.

Egli says this result gives him the confidence to keep working with their approach, to see if they can make it work with just the two chromosomes that are supposed to be there.

"[Egli's work] isn't the gold ring, but it's a major step forward, says stem-cell researcher George Daley, who works at Children's Hospital in Boston.

But even if Egli perfects his cloning techniques, there are still many people morally opposed to this kind of research. Daley says a new kind of cell, called an iPS cell, may prove to be just as good as an embryonic stem cell, and iPS cells can be made without eggs or embryos.

"The jury is still out as to whether the iPS cells are going to be the gold standard in the long run. In the near term, it's still the embryo-derived stem cells," says Daley. So for now, he thinks work with cloned human embryos should continue.

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All Things Considered–

Initially, Daniel Shechtman's discovery cost him a job and the respect of his colleagues.

The embryos would not be used for reproduction, but rather for the creation of embryonic stem cells.

Guy Raz talks with Insoo Hyun, associate professor of bioethics at Case Western Reserve University.

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Cloning Research Gives Way To Bioethics Questions

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Researchers in New York are reporting that, for the first time, they've used cloning techniques to successfully create human embryos in the lab. Guy Raz talks about the ethical implications of this research with Insoo Hyun, associate professor of bioethics at Case Western Reserve University.

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GUY RAZ, host: Now that scientists have used cloning techniques to create a human embryo, there's sure to be debate about the ethics of all this. Insoo Hyun is an associate professor of Bioethics at Case Western Reserve University, and he joins me now. Welcome to the program.

INSOO HYUN: Good to be here. Thank you.

RAZ: A we just heard from Joe Palca, some people are morally opposed to this kind of research. What is their argument?

HYUN: Well, some people may think that we are now down a slippery slope toward getting cloned babies. And that's certainly a major concern for policymakers and the public.

RAZ: Well, what about the possibility, though, of reproductive cloning? I mean, are we going down that slope?

HYUN: Well, as the research shows, human reproductive cloning is a really, really long ways away because human research clinics, just to get stem cells, is so difficult. And every technology has a good use and has a bad use. And the reasonable response to this fact is not to ban this technology altogether, but it's to prevent the abuses of this technology.

Reproductive cloning violates all international guidelines for stem cell research and all U.S. guidelines.

RAZ: But of course, every time new research like this comes out, that's the first thing people think about.

HYUN: Exactly. Many people go right to the science fiction scenarios of how this technology might spin out of control.

RAZ: Now, to make these cloned embryos, the ones that Joe was reporting on, scientists needed a supply of human eggs. These were researchers in New York. They seem to be able to get all they needed. But other researchers in other states have had problems convincing women to become egg donors. What did the researchers in New York do differently?

HYUN: The researchers in New York followed New York State laws in allowing for compensation for time, effort and inconvenience of the egg donors. Prior to that, all other attempts to recruit egg donors were miserable failures because women simply were not willing to provide their eggs under all that stress for free.

What's curious is that in all research locales, healthy research volunteers that give up part of their bodies for research - whether it's a little bit of a lung, a little bit of a liver or bone marrow - are very often paid for their time, effort, and inconvenience in recognition of that sacrifice and that effort they had to put in, to help the research team. Egg donors for stem cell research are the glaring exception in these states.

RAZ: So in New York, women can be paid. In other states, they can't be paid for donating eggs for research?

HYUN: Yes. In other states, they can get their expenses covered - whether it's cafeteria meals or parking tickets or babysitting fees - but they can't get any further financial recognition of their sacrifice.

RAZ: But in other instances, in those same states, they can get paid for donating eggs, right, if it's for other purposes?

HYUN: In all other states, women donors can get paid to donate their eggs to a couple who's seeking fertility treatment, that's certainly true.

RAZ: So explain the thinking behind the restrictions on paying women to donate eggs for this kind of research.

HYUN: The main concern is that when you put money on the table, women would not give a fully voluntary choice to participate. So the idea is that paying women for the time and inconvenience may be exploitative of women who are in desperate need of money. That's the main concern, that it undermines people's voluntary choice.

RAZ: Now, this research was done with private money. During the administration of George W. Bush, there were strict limits on federal funding for research on human embryonic stem cells. Many of those restrictions have been lifted by the Obama administration. Could this work today, that it was announced today, could it have been done with federal dollars?

HYUN: No, it could not have. One restriction is still in place, and that is that you cannot use federal funds to do research where embryos are created and destroyed in the process. But more importantly, researchers today cannot even study these new stem cell lines using federal funds because it came from a research embryo.

RAZ: If researchers are willing to use private money, are there still limitations on what kinds of stem cell research they can carry out in the U.S.?

HYUN: There are. You cannot, for example, put these cloned human embryos into a uterus to try to produce a pregnancy.

RAZ: But they still have greater leeway, right, and fewer restrictions than they would if they used federal money.

HYUN: That's absolutely correct. And that's why this research was able to get done in New York State.

RAZ: Insoo Hyun is an associate professor of Bioethics at Case Western Reserve University.

Professor Hyun, thank you so much.

HYUN: Thank you.

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