US researchers clone a monkey, get stem cells
Wed Nov 14, 2007 11:49am EST


By Maggie Fox, Health and Science Editor

WASHINGTON, Nov 14 (Reuters) - U.S. researchers have cloned monkeys and used
the resulting embryos to get valued embryonic stem cells, an important step
towards being able to do the same thing in humans, they reported on
Wednesday.

Shoukhrat Mitalipov and colleagues at Oregon Health & Science University
said they used skin cells from monkeys to create cloned embryos, and then
extracted embryonic stem cells from these days-old embryos.

This had only been done in mice before, they reported in the journal Nature.
Mitalipov had given sketchy details of his work at a conference in Australia
in June, but the work has now been independently verified by another team of
experts.

They said their work shows it is possible, in principle, to clone humans and
get stem cells from the embryos. But they said they only managed to create
two batches, or lines, of stem cells, so the method is still very
inefficient and difficult.

Embryonic stem cells are the source of every cell, tissue and organ in the
body. Scientists study them to understand the biology not only of disease,
but of life itself, and want to use them to transform medicine.

The idea would be to take a small piece of skin from a patient and grow
tissue or even organ transplants perfectly matched to the patient.

But their use is controversial, with opponents saying it is wrong to use a
human embryo in this way. U.S. President George W. Bush has repeatedly
blocked legislation that would expand federal funding of such research.

Mitalipov's team used classic somatic cell nuclear transfer to create their
embryos. This method involved taking the nucleus from an adult cell, in this
case a fibroblast, a type of skin cell.

Then an egg cell is hollowed out and the nucleus from the adult cell
inserted. This process in effect programs the egg into behaving as if it had
been fertilized and it can grow into a embryo.

A LOT MORE WORK

It was not an easy process. The researchers said they used 304 eggs from 14
rhesus macaque monkeys, and ended up with just two stem cell lines.

This means a lot more work before this would be useful for humans they
said -- especially given how hard human eggs are to come by.

It was important to confirm the work. A rival journal, Science, was forced
to withdraw papers published by South Korean scientist Hwang Woo-suk in 2004
and 2005 after his claims to have cloned a human embryo proved false.

Other cloning experts welcomed the Oregon work.

"The ability to produce embryo stem cells from cloned human embryos would
create entirely new opportunities to study inherited diseases," said Ian
Wilmut, director of the Scottish Centre for Regenerative Medicine at the
University of Edinburgh and a member of the team that cloned Dolly the sheep
in 1997.

"Cloned cells produced with the genetic material of a patient who has
inherited a disease would have the abnormalities associated with the
disease," Wilmut added in a statement.

The paper "provides the first convincing evidence that nuclear reprogramming
is feasible in primates," said Alison Murdoch and Dr. Mary Herbert of the
North-East England Stem Cell Institute in Newcastle.

"This is a very exciting development which takes us several steps closer to
the production of patient-specific stem cells to treat life-limiting
conditions such as Parkinson's, motor neuron disease, Huntington's disease
and cystic fibrosis."

(Editing by Julie Steenhuysen and Cynthia Osterman)

 Reuters2007All rights reserved

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