April 2, 2008 / 4:52 PM / 11 years ago

Scientists make human-cow embryos

WASHINGTON (Reuters) - Researchers say they have created embryos and stem cells using human cells and the egg cells of cows, but said such experiments would not lead to hybrid human-animal babies, or even to direct medical therapies.

Cattle in a file photo. British researchers say they have created embryos and stem cells using human cells and the egg cells of cows, but said such experiments would not lead to hybrid human-animal babies, or even to direct medical therapies. REUTERS/Shaun Best

Dr. Lyle Armstrong of Newcastle University presented preliminary data on his work to Israel’s parliament last week. It has not been reviewed by other experts in the field, Newcastle University said in a statement released on Tuesday.

They said they had hollowed out the egg cells of cattle, inserted human DNA to create a growing embryo, and then taken it apart to get embryonic stem cells.

Other experts agreed such work would only be an interim step aimed at understanding the biology of embryonic stem cells — the body’s ultimate master cells, which can give rise to all of the other cells and tissues.

“If the team can produce cells which will survive in culture it will open the door to a better understanding of disease processes without having to use precious human eggs. Cells grown using animal eggs cannot be used to treat patients on safety grounds but they will help bring nearer the day when new stem cell therapies are available,” John Burn, Head of the Institute of Human Genetics at Newcastle University, said in a statement.

Scientists hope to use stem cells to create a new field of so-called regenerative medicine. Doctors hope for eventual treatments for spinal cord injuries, diseases such as diabetes and even cancer.

Opponents of human embryonic stem cell research object to the destruction of human embryos and say even the tiniest embryo must be treated with dignity.

“This is one of the most controversial ethical issues in all of cloning and stem cell research,” Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania, said by e-mail on Wednesday.

Caplan noted many people may be disgusted or frightened by such work. “In my view there is no risk of making monsters this way. The biology will not work. Nor is that the intent of any of these experiments anyway, so I don’t think that fear is justified,” he said.


“I come down on the side that says if you can make great gains by making embryo hybrids in preventing premature death and understanding disease then a limited amount of such research is morally justifiable,” Caplan said.

Newcastle said Armstrong was granted a license by Britain’s Human Fertilisation and Embryology Authority to use animal eggs in such research.

Caplan noted the U.S. government does not regulate such work. President George W. Bush has vetoed several bills that would regulate the field because they would also all permit work on human embryos.

Dr. Robert Lanza of Massachusetts-based Advanced Cell Technology said his company tried, but failed, to create stem cells in a similar way in the late 1990s.

When two species are mixed together the result is called a chimera. While some are fanciful — a centaur, for example — others exist, such as sheep spliced with human genes that produce human proteins in their milk.

Many researchers are trying to do this to understand the secrets of stem cells and revolutionize medicine.

In 2004, Chinese researchers said they had created embryos by putting human DNA into a rabbit cell.

Experts are pursuing various ways to create stem cells. Several teams said last year they had re-programmed ordinary skin cells to act like human embryonic stem cells, but stressed that many different approaches need to continue before anyone fully understands how to regenerate human tissue and organs.

Reporting by Maggie Fox; Editing by Will Dunham and Sandra Maler

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