Stem Cells to Solve Ethical Dilemmas

New ways of creating embryonic stem cells without killing viable embryos are being reported, and this could potentially solve the biggest bioethical debate of the Bush administration.

On one hand, embryonic stem cells were made from a genetically abnormal embryo designed to be incapable of developing, and on the other hand, there was the attempt to fashion stem cells from an embryo without damaging it. The new methods offer laboratory answers to the moral questions raised by the destruction of human embryos and could result in the availability of more federal grants for one of the most promising fields of biomedical research.

William Hurlbut of Stanford University, a member of a White House bioethics advisory council, called it "a starting point for an important new dialogue" on possible "technological solutions for the moral problems surrounding human embryonic stem cell research."

Now the new question raising is about what sorts of laboratory creations deserve human status. Biochemist Fazale Rana at Reasons to Believe, a Christian group in Southern California opposed to human embryonic stem cell research says that the research is "right there on that boundary between what I would consider ethically permissible and potentially ethically troubling."

The debate is centered on the definition of "embryo," considered by some people to have the same moral status as a human being. In the new experiments, researchers crafted stem cell lines from lab creations characterized as "nonviable" entities.

Jaydee Hanson, director of human genetics at the International Center for Technology Assessment, a Washington, D.C., nonprofit organization that opposes some kinds of cloning and stem cell research on moral grounds states that "This is an attempt to solve an ethical issue through a scientific redefinition that really doesn't solve the issue."

President Bush made the production of any new stem cell lines ineligible for federal grants because such work involves the destruction of human embryos in 2001, and opposed cloning embryos, which scientists advocate as a way of creating specialized stem cell lines carrying disease genes or the DNA of an individual patient. This inspired California's $3 billion Proposition 71 initiative, which voters approved in the 2004 general election, as to pursue research banned from receiving federal support.

Stem cell researchers Rudolf Jaenisch and Alexander Meissner of the Whitehead Institute at the Massachusetts Institute of Technology showed how embryonic stem cells can be produced from a type of research cloning known as "alternate nuclear transfer": they devised a way to block the activity of a gene from an adult cell that would have allowed the cell to develop into an embryo once in the uterus. This way, the cell is nonviable because it lacks the ability to "establish the fetal-maternal connection" in the uterus; the abnormal DNA was then inserted into the nucleus of an egg whose own DNA had been removed.

Researchers showed though that they could still generate a specialized stem cell line, which would have the same DNA as that of the adult cell used to produce the cloned embryo and aimed to make "patient-specific" embryonic stem cells without destroying any potential life.

Another team of researchers led by Robert Lanza and Young Ching of Advanced Cell Technology, a Massachusetts biotech company, used another method: they used a single cell, known as a "blastomere," snipped from a developing embryo at the eight-cell stage. Known as "pre-implantation genetic diagnosis," the goal is to screen out disease-carrying embryos.

But the new approaches have only been tested on laboratory mice, and there's no guarantee similar results can be obtained in humans. Researchers insisted that an entity such as that produced in the MIT experiments has "no inherent principle of unity, no coherent drive in the direction of the mature human form."

"The tinkering doesn't change the essential nature of the cloned entity," said Hanson, of the International Center for Technology Assessment. "The only reason it's not an embryo is definitional."

Douglas Melton, a stem cell scientist at Harvard University, doubts critics of stem cell research will be stopped by the alteration of a single gene, because an altered embryo may still be considered an embryo.

Single cells transplanted into the uterus of the respective species are capable of propagating viable offspring and therefore, even if removing a single cell doesn't interfere with the developmental potential of the embryo, the isolated cell itself could be considered capable of embryo status.

Rudolf Jaenisch says that, despite all the arguments, it's still conceivable that special cloning or other techniques might be an acceptable compromise to allow expanding the federal role in stem cell research: "If one used this argument to protect cells developed through nuclear transfer because with further manipulation they might become a living clone, then every cell of our body would deserve the chance to become a human being. In not cloning them, each of us would be barring millions of individuals from getting a chance to live."

James Battey, head of a stem cell task force at the National Institutes of Health says that it is not clear yet if stem cells created by either of the new methods would qualify for federal grants.

Bernard Lo, a prominent bioethics expert at UCSF who also advises the California Prop. 71 program, called on those who object to stem cell research to consider the alternative derivation methods: "This work is really driven by a desire on the part of scientists to address the moral concerns some people have. So those people should say now if it doesn't settle the problem."

Stem cell strides may help resolve ethical dilemmas