BIOTECHNOLOGY researchers said they have developed a new way of producing stem cells that ultimately may not require the destruction of human embryos.
The announcement met with a cacophony of reaction from scientists and ethicists on both sides of the debate over stem-cell research. Several admired the science but said it was unlikely to quell the heated controversy over the morality of the research.
While many experts see stem cells as a potential source of treatments for degenerative or otherwise incurable conditions, many religious and ethical authorities object to stem-cell extraction as devaluing nascent human life. Since 2001, the U.S. has refused to fund any research involving other than a handful of already-existing stem-cell lines, many of them of limited usefulness to scientists.
The research team that said it has developed this new way of producing stem cells is from Advanced Cell Technology Inc., a biotechnology company in Alameda, Calif.
The team conducted its experiments with single cells extracted from tiny human embryos, each consisting of eight to 10 cells. By culturing those extracted cells in just the right way, the scientists were able to nudge some of them into developing as stem cells, the primordial building blocks capable of producing nerves, organs and every other type of tissue.
Until now, deriving new lines of stem cells has required researchers to suck out clumps of cells from five-day-old embryos -- typically unneeded ones, frozen during in-vitro fertilization procedures, that may otherwise face destruction. The process destroys the embryos.
Advanced Cell officials say their new technique offers the prospect of deriving new lines by simply extracting a single cell from an early-stage embryo. That process is already used in IVF clinics that scan for genetic flaws in newly fertilized embryos in order to determine which ones are most likely to grow into children. Extracting a cell or two generally doesn't appear to interfere with later fetal or childhood development, although the procedure can risk damaging the embryo
"You'd have a cell line and put the embryo at no increased jeopardy at all," says Robert Lanza, the Advanced Cell researcher who led the team. "On top of that, not only is there not a risk, but a benefit," he says, because the derived stem-cell line would be genetically matched to a child born from the same embryo, making it a theoretically convenient and safe source of cells for later medical treatment.
The Advanced Cell research, however, didn't focus specifically on the task of producing stem-cell lines by extracting a single cell without harming an embryo. As reported in their study published in today's edition of the journal Nature, the researchers experimented on 16 embryos and extracted a total of 91 individual cells for culturing. That procedure destroyed many of the embryos in question, Dr. Lanza said.
"It looks like they took the embryos apart and tried to create stem-cell lines from each of those cells" said Arnold Kriegstein, head of the stem-cell biology program at the University of California at San Francisco. But the work showed that single cells could be coaxed into becoming stem cells, which Dr. Kriegstein called "a significant achievement."
Extrapolating the results to single-cell extractions that don't harm viable embryos should be a straightforward task, says Dr. Lanza. Extrapolating the results to single-cell extractions that don't harm viable embryos, he says, should be a straightforward task.
"In terms of the actual biopsy and subsequent procedures, it's the same," he said. "It's just semantics." Dr. Lanza said that in some cases the team only took one or two cells from an embryo, and he added that some of the embryos experimented on continued to grow normally for another few days until they were again frozen.
The Advanced Cell team managed to produce two seemingly viable stem-cell lines from the 91 extracted cells and showed that the stem cells could give rise to a variety of tissue types. It remains unclear whether the newly produced lines, which derive from earlier-stage embryos than most existing stem cells, differ from other cell lines in any significant way. The results will also need to be confirmed in other laboratories.
Advanced Cell officials say they hope the results will mark a turning point for stem-cell research. Scientists working without federal funding are so far mostly focused on unraveling the mysteries of how the cells produce different tissue types. Commercially, the field is populated largely by tiny companies like Advanced Cell, which has plans to move ahead with early-stage clinical trials involving the cells in the next year or so.
Stem-cell related treatments, however, are likely at least a decade or more away. Among the hurdles are a lack of basic understanding of what makes the cells grow and repair damaged tissue and exactly how to use them as transplants without provoking immune-system reactions and other side effects.
Larger pharmaceutical and biotechnology companies have mostly steered clear of the field, in part because of the ethical controversy and the lack of federal research support. Advanced Cell Chief Executive William Caldwell, however, said he believes an embryo-safe method of deriving stem cells may help spark large-company interest in the area.
"I think this is going to help address the problem and the issues they have" with stem-cell derivation, Mr. Caldwell said. Advanced Cell, which is currently raising new funds in a private offering to bolster its meager cash reserves, hopes to sign a development partnership with a larger company by the end of the year.
Success or failure in that regard may depend on the extent to which the new technique succeeds in defusing moral qualms over the research. Several scientists and ethicists doubted any placating would happen. William Hurlbut, a Stanford University professor who serves on the White House bioethics council, worries that even single-cell biopsy may pose an unacceptable risk to embryos.
Others note that no one knows whether a single cell extracted from an early-stage embryo might also have the capability of developing into an individual human being. If the cell does have that potential, then destroying it to make a stem-cell line would still be morally problematic. "This thing is supposed to solve an ethical problem, but the ethical problem is not solved," says Davor Solter, the director of developmental-biology research at Germany's Max-Planck Institute of Immunobiology.
Dr. Lanza said there is no evidence to suggest that a single cell from such embryos can develop into an individual.
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