South Korea say they are the first to successfully clone a human embryo
S. Korean scientists clone human embryo
WASHINGTON -- Researchers in South Korea have become the first to successfully clone a human embryo, and then cull from it master stem cells that many doctors consider key to one day creating customized cures for diabetes, Parkinson's and other diseases.
This is not cloning to make babies, but to create medicine.
But it immediately revived controversy over whether to ban all human cloning, as the Bush administration wants, or to allow this "therapeutic cloning" that might eventually let patients grow their own replacement tissue.
"We have to do this research because of its promise for treating disease," said Dr. Moon Shin-yong of Seoul National University, who co-led the new research.
Without cloning, stem cells won't be genetically identical to the patient who needs them, causing "a rejection problem, and we would like to overcome it," Moon told The Associated Press.
"This kind of science should be conducted in South Korea and in the
United States. It is very important to medicine."
Embryonic stem cells are the body's building blocks, cells from which all other tissue types spring. They're present in an embryo only days after conception and are ethically sensitive because culling stem cells destroys the embryo.
Scientists have used therapeutic cloning to partially cure laboratory mice with an immune system disease. And they can cull stem cells from human embryos left over in fertility clinics.
But attempts to clone human embryos, to supply stem cells, have failed until now.
The Seoul scientists say they succeeded largely because of using extremely fresh eggs donated by South Korean volunteers and gentler handling of the genetic material inside them.
Moon and colleague Woo Suk Hwang are discussing the research Thursday at a meeting of the American Association for the Advancement of Science. Details will be published in the journal Science.
It's elegant work that provides long-anticipated proof that human therapeutic cloning is possible, said stem-cell researcher Dr. Rudolf Jaenisch of the Whitehead Institute for Biomedical Research in Cambridge, Mass.
Still, "it's not of practical use at this point," Jaenisch cautioned.
Years of additional research are required before embryonic stem cell transplants could be considered in people, he stressed.
Critics immediately urged Congress to ban all forms of human cloning. The House last year voted to do that, but the Senate stalled over whether there should be an exception for some research.
"The instrumentalization of human life for the benefit of others demeans the value of all human life," said Sen. Sam Brownback, R-Kan., who has sponsored legislation for a complete ban.
There's nothing to stop the next cloned embryo from being used for pregnancy, contended Richard Doerflinger of the U.S. Conference of Catholic Bishops.
"The how-to instructions have been posted," he said. "If you can bring an embryo to the one-week-old stage, you can implant that embryo in the womb. Once you do, no government can stop you unless they want to coerce abortions."
But stem-cell proponents hailed the research as a crucial first step to one day alleviating diabetes, Parkinson's and other diseases.
"It does show what is possible and provides hope to millions," said Daniel Perry of the Coalition for the Advancement of Medical Research.
U.S. scientists almost universally want a ban on reproductive cloning because the high rate of birth defects in cloned animals shows the technique is too dangerous - but scientific support for therapeutic cloning is high.
The South Korean research is "one tiny step closer to some medical use," said Laurie Zoloth, a Northwestern University bioethicist. "It is clearly time - now that it is more tangible - to set in place a process where we can have some kinds of experiments supported and some things banned."
"With 100 million patients waiting for breakthroughs in transplant medicine, it would be unethical to stop the research, especially now," added Carl Feldbaum of the Biotechnology Industry Organization. With "an uncertain political climate ... its no coincidence that much of the groundbreaking work in this field is being done overseas."
Internationally, the United Nations recently postponed a decision on what kinds of human cloning to ban. The United States is pushing for a total ban; Britain is leading the call for cloning for medical experiments to be left unhindered.
The Seoul researchers collected 242 eggs from 16 unpaid volunteers. Each woman also donated some cells from her ovary.
Using the same process as is used to clone animals, they removed the gene- containing nucleus of each egg and replaced it with the nucleus from the donor's ovarian cell.
Chemicals jump-started cellular division, resulting in 30 blastocysts, early-stage embryos that contain a mere 100 cells. From those, they harvested just one colony of stem cells - a small success rate.
Those stem cells began forming muscle, bone and other tissues in test tubes and when implanted into mice, the Seoul team reported.
Now, the team is studying how to direct which tissues those cells form, said Woo, who pledged in an e-mail interview to make the new cell line available to other interested scientists.
But Jaenisch lamented that many U.S. scientists couldn't work with the new cell line. Bush administration policy forbids any federally funded research on stem cells from embryos destroyed after Aug. 9, 2001
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Scientists Clone First Human Embryo Genetically Identical Cells May One Day Cure Disease
Feb. 12, 2004 -- Researchers in South Korea say they are the first to successfully clone a human embryo and use it to create stem cells that may one day provide the foundation for curing diseases from diabetes to Parkinson's.
"We are the first to report the development of cloned human embryonic stem cells, potentially capable of becoming any cell in the body," says researcher Woo Suk Hwang of Seoul National University in South Korea.
Hwang presented the results of the study today at a meeting of the American Association for the Advancement of Science (AAAS) in Seattle. The results also appear in today's issue of Science Express, the online version of the journal Science.
Researchers stress that this breakthrough is intended to pave the way for new custom-made medical treatments, not for human cloning.
Embryonic stem cells are the building blocks of life and the basis from which all other tissue cells are formed. The cells are found in the embryo only during the earliest stages of development and eventually diversify into millions of different cells.
By cloning human embryonic stem cells, researchers hope to replace damaged cells in the human body with genetically identical healthy cells to cure disease.
Embryonic stem cells have been created in the past using cells from mice and other animals, but achieving the same feat with human cells has proved too problematic until now.
"People have tried and utterly failed in the last couple of years to do it with human cells or primer cells, and they succeeded," says Rudolf Jaenisch, MD, professor of biology at the Whitehead Institute of the Massachusetts Institute of Technology. "That's an important step."
First Cloned Human Embryo Clears Major Hurdle
In the study, researchers collected 242 eggs and a sample of ovarian cells from 16 unpaid female volunteers. The scientists then removed the genetic material -- which contains the nucleus of each egg -- and replaced it with the nucleus from the donor's ovarian cell.
Then, using chemicals to trigger cell division, the researchers were able to create 30 blastocysts -- early-stage embryos that contain about 100 cells -- that were a genetic copy of the donor cells.
Next, the researchers harvested a single colony of stem cells from the blastocysts. These stem cells have the potential to grow into any tissue in the body. Because they are the genetic match to the donor, they aren't likely to be rejected by the patient's immune system.
Many Hurdles Left
Experts say practical use of stem cell transplants using cells derived from human embryos is still a long way off.
"In a real sense, it's still going to be years before we affect the treatment of a patient with this," says stem cell researcher John Gearhart, PhD, the C. Michael Armstrong Professor of Medicine at John Hopkins University.
Gearhart says there are still many problems that need to be solved. One of the biggest problems will be making the process more efficient. In this case, researchers used 242 eggs from 16 donors to obtain a single embryonic stem cell.
Researchers will also need to make sure that they can make embryonic stem
cells effectively into functional cells, which can be transplanted to treat diseases.
But Gearhart says the findings of this study may also help further scientific research in other areas by providing valuable new information on what is so unique about a human embryo.
For example, Gearhart says, "What is it about the egg that permits these nuclei from specialized cells to be reprogrammed? Wouldn't we love to know how that occurs at the molecular level?"
If researchers can answer that question, he says they may eventually learn how to reprogram cells without using an embryo.
Breakthrough Stirs Stem Cell Debate
The first successful cloning of a human embryonic stem sell is already stirring up an international ethical debate. Hwang and colleagues say they have enough stem cells in reserve and are willing to collaborate with any scientist who wishes to join them.
But the practice of using stem cells taken from human embryos is considered ethically sensitive because the embryo is destroyed once the stem cell is removed.
Current Bush administration policy forbids federally funded research on stem cells derived from human embryos destroyed after Aug. 9, 2001. Privately funded research on human embryonic stem cells is not restricted.
Jaensich says the federal limitations on embryonic stem cell research may impede the pace of progress of science in this area.
"The National Institutes of Health doesn't pay for it, and, therefore, the premier academic institutions here will not be able to do this research," says Jaenisch. "This really important research will be done in other countries, and it is a very troubling situation."
The Korean researchers attributed their success to using extremely fresh donor eggs, but they say this study was supported by private funds.
Some have questioned whether the publishing of the study in a medical journal amounts to providing an instruction book for others on how to create a cloned baby.
Donald Kennedy, editor-in-chief of Science, says the techniques laid out in the paper are designed for use only in developing new treatments for disease.
"It is a recipe only in the sense that 'catch a turtle' is the recipe for turtle soup," says Kennedy. "There is much difficulty that would remain for anybody who tried to use this technology as a first step toward reproductive cloning."
Human cloning is against the law in South Korea and some other countries. Most major medical organizations in the U.S., including the AAAS, have expressed opposition to reproductive cloning.
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