More Scientists Consider Embryo-Free Stem Cells

cns news ^ | 06.11.08 | Patrick Goodenough

[Coleus]

Some of Australia's leading bio-scientists are taking a closer look at a new, ethically acceptable stem cell research route that avoids the use of human embryos in the search for possible cures for degenerative diseases.  While not yet convinced that the "exciting" new method is as promising as using embryonic stem cells, they are studying the relative merits of the two approaches.  A major research breakthrough announced in Japan and the U.S. last November revealed that human "adult" skin cells can be reprogrammed into a new kind of cell -- an induced pluripotent stem (iPS) cell -- that shares an embryonic stem cell's potential to develop into other types of cell such as blood, brain and muscle.  In the same way as stem cells from embryos cloned from a patient's DNA would share that patient's genes, so too do iPS cells genetically match the donor whose skin cells were originally used. But unlike embryonic research, iPS cells sidestep the need to clone and destroy embryos.

For many ethicists and other observers, the discovery skewered the argument that scientists need to use embryos at all as they pursue potential therapies for diseases like Parkinson's and Lou Gehrig's. (Pro-lifers have long disputed that argument altogether, instead promoting adult stem cells from sources like bone marrow and placentas. But scientists argue that embryonic cells are more "pluripotent" -- or have greater potential to develop into any type of cell -- than adult ones. The iPS cell appears to share that property, but without the ethical difficulties.)  Bolstering the view that the science has taken a new direction, some leading scientists have shifted to using iPS cells rather than embryonic ones. Among the first to announce the move was Ian Wilmut, creator of the world's first cloned mammal, Dolly the sheep, and a longtime proponent of cloning human embryos for their stem cells.

Now, scientists in Australia -- a country that has long been in the forefront of global bio-tech research -- are examining the potential of iPS cells.  Researchers at the government-funded Australian Stem Cell Center (ASCC) in Melbourne last month took delivery of iPS cells from the U.S. and are now testing them.  The cells were imported under an agreement with Prof. James Thomson of the University of Wisconsin-Madison, who announced last November's iPS breakthrough simultaneously with scientists at Japan's Kyoto University.  ASCC scientist Andrew Laslett said this week the center believes it's too early to draw conclusions about which types of cells -- embryonic, cloned embryonic, adult or iPS -- would ultimately prove most useful in the search for therapies for diseases.  "We plan to comprehensively compare the iPS cell lines to existing human embryonic stem cell lines," he said. "These experiments will give us a greater understanding of the relative utility, advantages and potential barriers to the clinical use of iPS cells as compared directly to human embryonic stem cells."

Laslett called the iPS approach "a really exciting new area of research" and said there was a lot of interest worldwide.  At the same time the scientists are exploring iPS cells, Australian colleagues are pressing ahead with a bid to become the first in the world to clone human embryos and harvest stem cells from them. (A South Korean scientist claimed to have done so in 2005, but his supposed landmark study was subsequently discredited.)  Although a California-based bio-tech company last January announced that it had become the first to create a cloned human embryo, its researchers did not derive stem cells from it.

Australian researchers hope to achieve that milestone.   Scientists from Melbourne's Monash University, the ASCC and Sydney IVF, an infertility center, have submitted requests to the government to clone embryos, under new laws that came into effect last year.  They want to use a technique called "somatic cell nuclear transfer" (SCNT) - the transfer of a somatic cell into a donated human egg, the nucleus of which had been removed. The fertilized egg develops into an early-stage human embryo that is a "clone" of the donor. Its stem cells are then removed, and the embryo destroyed.  Sydney IVF research director Tomas Stojanov voiced optimism that a government licensing committee would give approval soon and that Australian researchers could achieve the world first.

More adult cell success

Elsewhere in Australia, researchers are reporting continuing progress in efforts to find medical treatments using adult stem cells taken from /lang3081 the lining of the human nose.  Professor Alan Mackay-Sim, leader of a team at Griffith University, reported that stem cells taken from the noses of patients with Parkinson's and transplanted into the brain of a rat, gave rise to brain cells that produce dopamine, a chemical that helps control coordination and movement.   The researchers, whose study was published in the journal Stem Cells , simulated Parkinson's symptoms in rats, causing them to run in circles. They then injected the nasal cells into the affected part of the creatures' brains and the rats, Mackay-Sim said, soon regained the ability to run in straight lines.

"All animals transplanted with the human cells had a dramatic reduction in the rate of rotation within just three weeks," he said.   He also noted that none of the transplanted cells had led to the formation in the rats of potentially cancerous tumors, as happened when embryonic stem cells were similarly transplanted.  Mackay-Sim's team has been working in the adult stem cell area for several years, supported in part by grants from the Catholic Church archdiocese in Sydney.  The olfactory cells, which the researchers say a/lang3081 re simple to extract and relatively easy to grow, can differentiate into heart, nerve, liver and brain cells.

Embryonic stem cell research has become one of the most controversial ethical issues of recent times. President Bush in 2001 limited federal funding for the research to work using a specified number of then-existing stem cell lines, and twice since then has vetoed legislation that aimed to expand the funding. There are no restrictions on private funding in the U.S.   Later this week, the U.S. Conference of Catholic Bishops at a conference in Florida plans to vote on a statement which, if approved by two-thirds of its members, will be the bishops' first formal text specifically on the issue.  The statement will declare that the destruction of embryos for stem cells to be used in research for possible future treatments, whether funded by the government or not, is not ethically justified.

[ClearCase_guy]

While not yet convinced that the "exciting" new method is as promising as using embryonic stem cells,

Not as promising as the embryonic stem cells which so far have delivered no medical treatments? Not as promising as the embryonic stem cells which seem to cause cancer with great frequency? Well, it will be hard to be less promising ...