British scientists make human-cow embryos

WASHINGTON (Reuters) - British researchers say they have created embryos 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.

Dr. Lyle Armstrong of Newcastle University presented preliminary data on his work to Israel's parliament last week, Newcastle University said in a statement released on Tuesday.

They said they had hollowed out the egg cells of cattle and inserted human DNA to create a growing embryo. The hope would be to take it apart to get embryonic stem cells.

Details of the work were not available because the researchers have not yet published their study in a scientific journal -- the usual route for reporting such experiments.

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.

"They put human DNA into a cow egg and got the usual early-stage embryos you'd expect," said Dr. Robert Lanza of Massachusetts-based Advanced Cell Technology, whose company tried, but failed, to create stem cells in a similar way in the late 1990s.

"It's too early to say whether this is different or new," agreed Susannah Baruch of the The Genetics and Public Policy Center in Washington.

John Burn, head of the Institute of Human Genetics at Newcastle University, said the idea is to save "precious human eggs" in making stem cells using cloning technology.

"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," he said in a statement.

REGENERATIVE MEDICINE

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

Opponents of human embryonic stem cell research object to the destruction or manipulation of human embryos.

"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.

"This is the kind of technology that will raise concerns," Baruch agreed. "But you shouldn't underestimate people's interest and willingness to think hard about these new technologies."

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

President George W. Bush has vetoed bills that would regulate the field because they would also all permit destruction of human embryos.

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.

(Editing by Will Dunham and Sandra Maler)