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Chinese Stem-Cell Advance Met With Cautious Optimism
BY Joan Frawley Desmond REGISTER CORRESPONDENT
August 23-September 5, 2009 Issue |
Posted 8/14/09 at 11:05 AM
WASHINGTON — Three separate teams of
researchers in China and the United States have published papers confirming
that reprogrammed mouse skin cells could behave exactly like embryonic stem
cells.
The scientific community — as well
as pro-life groups eager to discourage the advance of embryo-destructive stem-cell
research — applauded the promising news. But both camps caution that more work
must be completed before the full promise of induced pluripotent skin stem
cells, known as iPSCs, can be understood.
“The recent papers from China and
the Scripps Institute are very interesting and hopeful. They advance the notion
that iPSCs are capable of producing live-born mice,” said Dr. William Hurlbut,
a consulting professor in neurology and the neurological sciences at Stanford University.
But Hurlbut, who has taught courses
in bioethics, served on the President’s Council on Bioethics during the Bush
administration, and is engaged in related scientific research, presents an
ambiguous portrait of the impact of this new development on the culture wars.
He noted that most of the reprogrammed stem cells failed to work and that only
a few lines yielded an “apparently normal” adult mouse.
“It probably means there are a lot
of technical barriers. To be commercially viable, they would have to be
reliably pluripotent. They will have to look for what is in the lines of mice
that work versus the ones that don’t work,” suggested Hurlbut. “I spoke with
Shinya Yamanaka, the Kyoto University scientist that initiated this advance,
and he says there is still a lot of work to do.”
According to the paper published in
the science journal Nature, the
researchers, led by Qi Zhou at the Chinese Academy of Sciences’ State Key
Laboratory of Reproductive Biology, sought to establish whether the
reprogrammed mouse skin cells could yield the same pluripotent characteristics
common to embryonic stem cells; embryonic stem cells can morph into other cells
in the body. The Chinese study confirmed that iPSCs were roughly equivalent to
embryonic stem cells when they implanted the reprogrammed skin cells into a
female mouse embryo and transferred that embryo to a female mouse, which later
had pups.
Fanyi Zeng of the Shanghai Institute
of Medical Genetics at Shanghai Jiao Tong University told Reuters that the
research would help scientists target “the root causes of disease and lead to
viable treatments and cures of human afflictions.”
Researchers and patient advocates
have long contended that embryonic stem cells offer the potential to lead to
medical miracles, such as regenerating tissue damaged by trauma and disease.
While states like California have
designated billions of dollars for embryonic stem-cell research and President
Obama fulfilled his campaign pledge to relax key restrictions on federal
funding of embryonic stem-cell research, the “promise” of this work has yet to
be realized.
Meanwhile,
scientists working with adult stem cells have produced a string of new
therapies, and hundreds of laboratories are now engaged in iPSC research.
The news from China has already
fired pro-lifers’ hopes that the scientific community will reconsider its
commitment to embryonic stem-cell research, but iPSC research also possesses a
dark side: It may well facilitate the process of human cloning.
Zeng, from the Shanghai Institute,
rejected this path, and U.S. scientists who work with stem cells insist they
have no plans to bring a cloned human to term. At present, some engage in
“therapeutic cloning” — embryos are created for the purpose of research and
then killed.
“Any cell that is capable of
producing a live-born mouse can produce a cloned being. The issue of cloning
has existed for embryonic stem cells, and now it also exists for iPSC,” said
Maureen Condic, associate professor of neurobiology and anatomy at the
University of Utah.
Condic suggests that iPSC advances —
“a less-specialized technology” — may even surpass the effectiveness of
traditional cloning, which “rarely yields an embryo capable of developing up
through live birth.”
In traditional cloning, a cell is
obtained from a patient and then combined with a human egg cell that has had
its own DNA removed. The combined cell is stimulated to divide, and once
transferred to a surrogate mother, such clones can develop to live birth in
rare cases.
This approach poses a number of
significant challenges. Condic noted that “obtaining a sufficient number of
human eggs is a barrier.” Few women want to undergo a risky and painful medical
procedure for the sake of science.
Father Thomas Berg of the
Westchester Institute for Ethics and the Human Person believes it will be
critically important to get “laws on the books prohibiting the use of iPSC, as
well as embryonic stem cells, for human cloning.”
“Right now, human cloning is taboo
in the scientific community, but taboos don’t last forever,” observed Father
Berg. “This procedure could be very attractive to the in vitro fertilization
industry because it doesn’t have any of the complexity of cloning. If that
industry wants to create a ‘savior sibling,’ for example, this procedure would
produce the clone of whoever donated those skin cells.”
Alternative Path
The “potential dark side of cloning”
is a blow to Father Berg, who has collaborated for years with stem-cell
researchers and bioethicists to initiate alternatives to embryo-destructive stem-cell
research. Still, he is pleased that scientists have embraced the option of
employing reprogrammed skin cells instead of stem cells stripped from early
embryos.
Also hopeful is Father Tad
Pacholczyk, director of education for the National Catholic Bioethics Center,
given that iPSCs have opened up an alternative path for stem-cell research that
may lead to major breakthroughs in the treatment of spinal cord injuries and
neurological diseases. “We now have a cell type that will allow us to do the same
experiments that we wanted to do using embryonic stem cells — and we won’t find
ourselves in any ethical quagmire,” he said.
Father Pacholczyk believes that
those championing embryo-destructive research are the minority: “When you look at the
stem-cell field, you have a relatively small core group of scientists who will
incessantly beat the drum of embryo destruction, [believing] no matter what, we
have to be able to destroy human embryos.”
He suggests that a much larger
segment of scientists “have always been sensitive to the ethical concerns in
this field. An enormous number of them are doing research with the reprogrammed
cells,” embracing the promise of iPSCs.
As iPSC research builds momentum,
Father Pacholczyk is troubled that Obama has signaled plans for a larger
federal role in embryonic stem-cell research. In his eyes, “This ends up being
a kind of sanctioning of embryonic stem-cell research.”
Yet, Father Pacholczyk, a
neuroscientist, is sympathetic to the concerns of the scientific community that
now possesses the tools “to ask developmental questions we could never ask
before.”
“Scientists can be a little bit
naive when they say, ‘Don’t impede us too much with talk about ethics. After
all, we are trying to achieve good things.’ That posture has always been
present in the scientific community and always will be,” he said. “But the
stem-cell field has exploded in front of us, and enormous possibilities do seem
to be presenting themselves.”
Engage Science
If Catholic theologians and pro-life
activists seek to engage the scientific community, Hurlbut suggests, they must
do more than advance their own moral concerns.
Hurlbut is prepared to sound the
alarm about new efforts to circumvent or even rescind the Dickey-Wicker
Amendment, which banned taxpayer-funded research that engaged in the creation
and killing of human embryos.
But Hurlbut also wants political
activists concerned with life issues to establish a dialogue that acknowledges
the profound curiosity that drives scientific innovation even as it seeks to
guard against the excesses of this passion.
“The pro-life movement has made a
mistake emphasizing adult stem cells over embryonic stem cells,” suggested
Hurlbut. “There are scientific reasons to believe in the value of embryonic
stem-cell research. Even as a pro-life person, I can see why scientists want to
study embryonic stem cells — there is basic scientific information to be
learned from them.”
Scientists devoted the past century
to molecular biology, learning about the components of cells, he noted. “Now
they’ve moved into the era of developmental biology, working with living
beings. We need to use the simplest model — the embryo — to learn about this.
That’s why I don’t think this will be the end of the culture wars. It’s the
beginning of a whole series of conflicts of the meaning of developing life.”
Joan Frawley Desmond writes
from Chevy Chase, Maryland.
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