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[Amber Hewins <ahewins AT mac.com>]

http://www.nytimes.com/2007/11/15/science/15primate.html?_r=1&hp&oref=slogin

The New York Times
November 15, 2007
Scientists Use Monkey Clones to Extract Stem Cells
By GINA KOLATA

Researchers in Oregon are reporting that they used cloning to produce monkey 
embryos and then extracted stem cells from the embryos.

Not only is this the first time such cells have been produced in any animal 
other than a mouse, but the method, the researchers say, should also work in 
humans. In 2004, South Korean researchers reported making stem cells from 
cloned human embryos, but the claim turned out fraudulent.

?We hope the technology will be useful for other labs that are working on 
human eggs and human cells,? the lead researcher of the group, Shoukhrat 
Mitalipov at Oregon Health and Science University in Beaverton, said in a 
telephone interview. ?I am quite sure it will work in humans.?

The monkey stem cells were genetically identical to an adult monkey, Semos, 
whose cells were cloned. They are a sort of universal cell that can, in 
theory, develop into any tissue or organ.

Medical researchers and patient advocacy groups have long hoped to use human 
embryonic stem cells to study diseases and supply replacement cells to treat 
them. So far, though, stem cell research has not yielded cures, and many 
obstacles lie ahead.

An advantage of using cloning to obtain stem cells is that they would 
genetically match a patient?s cells, making it unnecessary to suppress the 
immune system if the stem cells are used in treatment. Cloning could also 
produce stem cells that genetically match patients with complex diseases like 
Alzheimer?s. That might let scientists study those cells and understand how 
the diseases progress.

With the monkey work, some researchers say, cloned human embryonic stem cells 
seem more feasible. There is no way to know, of course, whether it will be 
harder or easier to repeat the work with humans. ?I?m very enthusiastic,? 
said Dr. Leonard Zon, director of the stem cell program at Harvard?s 
Children?s Hospital. ?The next step is definitely doing it in humans.?

Groups opposing human cloning and the destruction of human embryos to extract 
stem cells say the report makes it more urgent than ever to draw a moral line.

?I certainly think that this represents a new threshold in the entire 
discussion,? said the Rev. Tadeusz Pacholczyk, director of education at the 
National Catholic Bioethics Center. ?At this point, it becomes essential to 
ask a question as a society: Are there ever going to be circumstances where 
it is morally justifiable to clone human beings??

The report on cloned stem cells, which appears in the Nov. 22 issue of 
Nature, was published online yesterday, after some details of the work had 
filtered into the news media.

Dr. Mitalipov said his team showed that the cloned cells had features 
characteristic of universal cells. For instance, they developed into monkey 
heart cells and nerve cells.

The team also put the cells in mice, where they turned into a wide array of 
cell types.

The stem cells, Dr. Mitalipov says, ?can contribute to any cell of the body.?

The scientists began by removing skin cells from a 9-year-old adult male 
rhesus macaque and inserted them, along with all their genes, into monkey 
eggs whose genetic material had been removed.

The egg, in a part of the cloning process that remains mysterious, 
reprogrammed the genes from the skin cells, bringing them back to the state 
they were in when embryo development begins.

The reprogrammed genes took over developing the eggs. A result was monkey 
embryos that were genetically identical ? clones ? of the adult male monkey. 
A few days later, the investigators extracted stem cells from the embryo 
clones, destroying the embryos in the process.

Most attempts at cloning failed. The investigators started with 304 egg cells 
from 14 female macaques and ended up with two stem cell lines. One line had 
an abnormal Y chromosome. The other, Dr. Mitalipov said, appeared normal.

But, he speculates, one reason for the success was finding a gentle way to 
take the genetic material out of monkey eggs.

In previous attempts, the investigators had used a method that worked well in 
mice. They marked the egg?s chromosomes with a dye that glowed under 
ultraviolet light. That let them see the chromosomes and be sure that they 
were removed before they inserted the adult cell with its genes into the egg.

The dye and ultraviolet light, the researchers surmised, might damage the 
egg. So they used a new method that shines polarized light through the egg, 
allowing them to see the chromosomes directly, without dyes.

Randall Prather, professor of reproductive biotechnology at the University of 
Missouri, said he had had similar problems with the dyes and ultraviolet 
light when he tried to clone pigs. His group succeeded by going in blindly 
and plucking the nuclei out of the pigs? eggs, he said.

?Each system has a quirk to make it work,? Dr. Prather said.

Dr. Mitalipov said that once his group decided to use its modified methods of 
producing the cloned embryos, it took just a few months to produce the stem 
cells.

Dr. Mitalipov says his group?s next project is to use its new method to try 
to create cloned monkeys that carry genes for human diseases. The researchers 
would add human disease genes to adult skin cells before starting the cloning.

A result would be cloned monkeys that had the human disease gene in every 
cell. Scientists could study those monkeys to understand the causes and 
treatment of the disease.

?We hope,? Dr. Mitalipov said, ?to model every known human disease.?