Stem cell breakthrough uses no embryos

[Guest guest]

NEW YORK - Scientists have made ordinary human skin

cells take on the chameleon-like powers of embryonic stem cells, a startling

breakthrough that might someday deliver the medical payoffs of embryo cloning

without the controversy.

 

Laboratory teams on two continents report success in a pair of

landmark papers released Tuesday. It's a neck-and-neck finish to a race

that made headlines five months ago, when scientists announced that the

feat had been accomplished in mice.

 

The & quot;direct reprogramming & quot; technique avoids the swarm of ethical,

political and practical obstacles that have stymied attempts to produce

human stem cells by cloning embryos.

 

Scientists familiar with the work said scientific questions remain

and that it's still important to pursue the cloning strategy, but that

the new work is a major coup.

 

& quot;This work represents a tremendous scientific milestone — the biological

equivalent of the Wright Brothers'

first airplane, & quot; said Dr. Robert Lanza, chief science officer of

Advanced Cell Technology, which has been trying to extract stem cells

from cloned human embryos.

 

& quot;It's a bit like learning how to turn lead into gold, & quot; said Lanza,

while cautioning that the work is far from providing medical payoffs.

 

& quot;It's a huge deal, & quot; agreed Rudolf Jaenisch, a prominent stem cell

scientist at the Whitehead Institute in Cambridge, Mass. & quot;You have the

proof of principle that you can do it. & quot;

 

The White House lauded the papers, saying such research is what President Bush

was advocating when he twice vetoed legislation to pave the way for

taxpayer-funded embryo research.

 

There is a catch with the new technique. At this point, it requires

disrupting the DNA of the skin cells, which creates the potential for

developing cancer. So it would be unacceptable for the most touted use

of embryonic cells: creating transplant tissue that in theory could be

used to treat diseases like diabetes, Parkinson's, and spinal cord

injury.

 

But the DNA disruption is just a byproduct of the technique, and experts said

they believe it can be avoided.

 

The new work is being published online by two journals, Cell and

Science. The Cell paper is from a team led by Dr. Shinya Yamanaka of

Kyoto University; the Science paper is from a team led by Junying Yu,

working in the lab of in stem-cell pioneer James Thomson of the University of

Wisconsin-Madison.

 

Both reported creating cells that behaved like stem cells in a series of lab

tests.

 

Thomson, 48, made headlines in 1998 when he announced that his team had isolated

human embryonic stem cells.

 

Yamanaka gained scientific notice in 2006 by reporting that direct reprogramming

in mice had produced cells resembling embryonic stem cells,

although with significant differences. In June, his group and two

others announced they'd created mouse cells that were virtually

indistinguishable from stem cells.

 

For the new work, the two men chose different cell types from a

tissue supplier. Yamanaka reprogrammed skin cells from the face of an

unidentified 36-year-old woman, and Thomson's team worked with foreskin

cells from a newborn. Thomson, who was working his way from embryonic

to fetal to adult cells, said he's still analyzing his results with

adult cells.

 

Both labs did basically the same thing. Each used viruses to ferry

four genes into the skin cells. These particular genes were known to

turn other genes on and off, but just how they produced cells that

mimic embryonic stem cells is a mystery.

 

& quot;People didn't know it would be this easy, & quot; Thomson said.

& quot;Thousands

of labs in the United States can do this, basically tomorrow. & quot;

 

The Wisconsin Alumni Research Foundation, which holds three patents

for Thomson's work, is applying for patents involving his new research,

a spokeswoman said. Two of the four genes he used were different from

Yamanaka's recipe.

 

Scientists prize embryonic stem cells because they can turn

into virtually any kind of cell in the body. The cloning approach —

which has worked so far only in mice and monkeys — should be able to

produce stem cells that genetically match the person who donates body

cells for cloning.

 

That means tissue made from the cells should be transplantable

into that person without fear of rejection. Scientists emphasize that

any such payoff would be well in the future, and that the more

immediate medical benefits would come from basic research in the lab.

 

In fact, many scientists say the cloning technique has proven

too expensive and cumbersome in its current form to produce stem cells

routinely for transplants.

 

The new work shows that the direct reprogramming technique can

also produce versatile cells that are genetically matched to a person.

But it avoids several problems that have bedeviled the cloning

approach.

 

For one thing, it doesn't require a supply of unfertilized

human eggs, which are hard to obtain for research and subjects the

women donating them to a surgical procedure. Using eggs also raises the

ethical questions of whether women should be paid for them.

 

In cloning, those eggs are used to make embryos from which stem

cells are harvested. But that destroys the embryos, which has led to

political opposition from President Bush, the Roman Catholic church and others.

 

 

Those were & quot;show-stopping ethical problems, & quot; said Laurie Zoloth,

director of Northwestern University's Center for Bioethics, Science and

Society.

 

 

The new work, she said, & quot;redefines the ethical terrain. & quot;

 

Richard Doerflinger of the U.S. Conference of Catholic Bishops

called the new work & quot;a very significant breakthrough in finding morally

unproblematic alternatives to cloning. ... I think this is something

that would be readily acceptable to Catholics. & quot;

 

 

White House spokesman Tony Fratto said the new method does not cross what Bush

considers an & quot;ethical line. & quot; And Republican Sen. Tom Coburn of

Oklahoma, a staunch opponent of publicly funded embryonic stem cell research,

said it should nullify the debate.

 

Another advantage of direct reprogramming is that it would

qualify for federal research funding, unlike projects that seek to

extract stem cells from human embryos, noted Doug Melton, co-director

of the Harvard Stem Cell Institute.

 

Still, scientific questions remain about the cells produced by

direct reprogramming, called & quot;iPS & quot; cells. One is how the cells compare

to embryonic stem cells in their behavior and potential. Yamanaka said his work

detected differences in gene activity.

 

 

If they're different, iPS cells might prove better for some scientific

uses and cloned stem cells preferable for other uses. Scientists want

to study the roots of genetic disease and screen potential drug

treatments in their laboratories, for example.

 

 

Scottish researcher Ian Wilmut, famous for his role in cloning Dolly the sheep a

decade ago, told London's

Daily Telegraph that he is giving up the cloning approach to produce

stem cells and plans to pursue direct reprogramming instead.

 

Other scientists said it's too early for the field to follow

Wilmut's lead. Cloning embryos to produce stem cells remains too

valuable as a research tool, Jaenisch said.

 

Dr. George Daley of the Harvard institute, who said his own lab

has also achieved direct reprogramming of human cells, said it's not

clear how long it will take to get around the cancer risk problem. Nor

is it clear just how direct reprogramming works, or whether that

approach mimics what happens in cloning, he noted.

 

 

So the cloning approach still has much to offer, he said.

 

 

Daley, who's president of the International Society for Stem Cell Research, said

his lab is pursuing both strategies.

 

 

& quot;We'll see, ultimately, which one works and which one is more

practical. & quot;

 

 

 

 

 

Group Moderatordimpill_gang To dimpill's gang! This is

the Best Place to Hang around.We Give u the Best in Latest News, Jokes, Funny

Pictures,Wallpapers,Latest Buzz and Much More! Connect your World with Us join

Now dimpill_gang/join Affiliated group from

dimpill_gang for Only Adult Mails fantazies/join

 

_____________

No banners. No pop-ups. No kidding.

Make My Way your home on the Web - http://www.myway.com