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Stem cell find might ease stalemate

US scientists say they have devised two new methods of extracting precious embryonic stem cells from mice without destroying their pre-existing ability to generate life, potentially offering a way out of a protracted political stalemate over regenerative medicine.

The announcement, made on Sunday by Massachusetts-based Advanced Cell Technology, Inc (ACT) and the Whitehead Institute for Biomedical Research, comes amid a heated debate in the US about whether current limits on federal funding for embryonic stem cell research should be lifted to give scientists a chance to explore what many call one of the most promising areas of biological science.

US President George W. Bush four years ago imposed a ban on federal financing of new embryonic stem cell lines, in which embryos are destroyed as the result of the extraction of the cells. He ordered that US government funds be used to support only "existing" lines, "where the `life-and-death decision' has already been made."

But critics say the policy robs scientists of a unique opportunity to find cures for cancer, Alzheimer's and Parkinson's diseases, heart ailments, spinal cord injuries and scores of other conditions.

Embryonic stem cells, considered the building blocks of life, can be grown into any of the 200 cell types encountered in the human body and thus be used to replace defective tissues.

ACT researchers said they had been able to produce five embryonic stem cells and seven extraembryonic stem cell lines from a single mouse without interfering with the developmental potential of its embryos.

"The stem cells were able to generate all the cell types of body, including nerve cells, bone and beating heart," said Young Chung, a senior scientist with the company and one of the top researchers on the project.

Meanwhile, the Whitehead Institute bio-genetic team has succeeded in creating genetically altered mouse embryos unable to implant in a uterus and thus generate life.

Under this procedure, the DNA of the donor nucleus is altered before it is transferred into an egg cell so that the resulting blastocyst has no chance of becoming a viable embryo.

However, embryonic stem cells remain able to divide and replicate themselves -- and can be harvested without destroying what some consider to be life, according to the announcement.

"The purpose of our study was to provide a scientific basis for the ethical debate," said Rudolf Jaenisch, the lead author of the study, which is to be published in the journal Nature.

Both scientific teams said they saw no reasons why their cell extraction methods could not work in humans.

However, Jaenisch warned that human embryonic stem cells are extraordinarily complicated and scientists must be able to use "all known tools and techniques" in order to realize the full therapeutic potential of the field.

In what appeared to be a veiled shot at congressional efforts to further limit stem cell research, Robert Lanza, medical director at ACT, said "it would be tragic" not to pursue all options and methods available to scientists to get these new technologies to patients.

The US House of Representatives in recent years has twice passed anti-cloning legislation that would ban the creation of human embryos through cloning, also known as somatic cell nuclear transfers. The bills stalled in the Senate.

While hailing the two studies late on Sunday, the Coalition for the Advancement of Medical Research reminded that under the House measures, the researchers could have faced criminal charges if they experimented with human cells.

"It is imperative to expand the current federal stem cell policy, and ensure that somatic cell nuclear transfer remains legal in the United States," the coalition said in a statement.
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