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Ethics dilemma obstructs embryonic stem cell research
Monday, March 26, 2001 By Byron Spice, Science Editor, Post-Gazette
Tissue engineering was so much simpler back in the days when it was so much harder. At least, from Alan Russell's perspective, it was simpler in ethical and moral terms. No one ever lost much sleep, for instance, over using foreskins to make artificial skin for burn patients, explained Russell, executive director of the Pittsburgh Tissue Engineering Initiative.
Today, ambitions have ballooned, as biotechnologists work on ways to treat strokes with neuron transplants, use polymer coatings to keep coronary arteries from narrowing and eventually grow replacement livers, muscles and other tissues. But one of the hottest topics in tissue engineering -- embryonic stem cells -- also is its most troubling.
Scientists believe almost any type of cell in the body could be produced from these embryonic stem cells, perhaps leading to cures for such diseases as diabetes, Parkinson's and muscular dystrophy. But the only way to obtain those cells is to destroy human embryos, a fact that has landed tissue engineering in the midst of the abortion controversy.
"There's a lot of 'Sophie's Choices' in this," said Russell, a biochemist and molecular biologist who heads the University of Pittsburgh's chemical engineering department.
Stem cells will be on the minds of 400 to 500 tissue engineering researchers expected to attend the three-day Engineering Tissue Growth international conference that begins tomorrow at the Marriott City Center. Several researchers will be presenting papers regarding stem cells -- the adult-derived type, not the embryonic type -- and how they might be used for such tasks as repairing the central nervous system.
Embryonic stem cell research, now performed by only a handful of researchers, could soon burgeon, depending on the outcome of a debate within the Bush administration and the Congress.
The National Institutes of Health last year issued guidelines for funding research on embryonic stem cells. The research would be performed using left-over embryos produced by in-vitro fertilization clinics that would otherwise be discarded.
Many abortion foes, contending that the unimplanted embryos are every bit as human as a fetus, have opposed the NIH plans. President Bush has expressed his personal opposition to this type of research and has asked Health and Human Services Secretary Tommy Thompson -- an abortion foe but, as Wisconsin governor, a supporter of embryonic stem cell research -- to review the guidelines.
Biotechnology experts worry that without such research, U.S. biotech companies might fall behind those in other countries, notably Britain, that allow embryonic stem cell experiments. Last week, a committee of the Canadian Institutes for Health Research proposed allowing embryonic cell research.
At the heart of the issue, said Michael Brannigan, executive director of the Center for Ethics Studies at LaRoche College, is whether an embryo has "moral status" -- whether it has such basic human rights as the right to exist.
"The issue of moral status is one that philosophers have been debating for decades," Brannigan said. For those who believe embryos have moral status, it isn't possible to justify destroying an embryo to obtain its stem cells. Abortion foes, moreover, fear that allowing experimentation on embryos creates a "slippery slope" that could be used to justify abortions as well.
"One can't discredit that line of thinking," Brannigan acknowledged, though he personally is not convinced of an embryo's moral status. Proponents of the research maintain that the embryo doesn't have moral status, he added, and that manipulating or destroying embryos is justified, particularly if it is done to achieve a greater good.
Russell is personally conflicted. An embryo is human life, he said, emphasizing that he was not speaking on behalf of the tissue engineering group he heads. "It's not just a clump of cells; that clump of cells is a life." Yet he finds it difficult to conceive of even adult-derived stem cell research being able to advance without embryonic stem cell research.
Adult-derived stem cells, such as the stem cells in bone marrow that give rise to all of the blood cells, originally were thought to have much less potential than embryonic stem cells.
The adult cells normally produce only a narrow range of cells -- blood cells, or muscle cells, or brain cells, depending on the type of stem cell. But experiments at Pitt and other research centers in recent years now suggest that adult-derived stem cells can be reprogrammed, so that a blood stem cell can give rise to, say, a liver cell or a brain cell.
Using adult-derived stem cells in this way would allow researchers to sidestep the moral minefield of embryos. "But the reality is none of us really know the potential [of adult-derived stem cells] yet," Russell said. For the foreseeable future, parallel experiments with both adult-derived and embryonic stem cells will be needed until scientists understand the capabilities of each type.
"You're going to have to find a way to find and collect embryonic cells if the work with adult-derived cells is going to make sense," Russell maintained. He admitted he doesn't know how that can be done yet.
Moreover, the federal government needs to develop a national tissue engineering policy to make sure these questions are addressed properly, he said. He fears that, if the NIH goes ahead with embryonic stem cell research, adult-derived cell work will languish as scientists gravitate to what appears to be the more promising cell type. Priorities should be set to maintain funding for both types of stem cells, he said.
The Engineering Tissue Growth conference begins tomorrow at the Marriott City Center. More than 70 experts will make presentations and actor/director/research advocate Christopher Reeve will speak at a closing dinner Thursday night. For more information, call RiverPoint TradeShows at 412-471-3974
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