Thursday, July 24, 2008| As noted by Darryn Bennett in her July 16 article, new methods of reprogramming adult skin cells offer an alternative to human embryonic stem cells, but “other ethical questions surrounding access and the testing process” remain.

Indeed, others have claimed that reprogramming — or what scientists call “induced pluripotent cells” — will end the ethical debate over stem cell research. But the collective sigh of ethical relief may be premature. 

As widely reported, the new reprogramming method began with the discovery of a combination of just four genes that would, in the hands of researchers, induce ordinary skin cells to revert to an earlier stage of development. The result was pluripotent stem cells that have or mimic the therapeutic potential of embryo-derived stem cells. This scientific breakthrough has been rightly hailed as a huge advance. For one thing, the new method bypasses the need to use embryos for the production of pluripotent stem cells. The new cells come from skin cells rather than blastocysts — the very early stage embryos from in vitro fertilization (IVF) clinics that are the source of human embryonic (ES) cells. The new method is also an alternative to the production of pluripotent cells through Somatic Nuclear Cell Transfer (SCNT) — therapeutic cloning, which raises ethical suspicion not only because of its human cloning potential, but because it requires healthy young women to undergo the health risks of hormone treatments and surgery to provide the hundreds of eggs (oocytes) required to produce each genetically matched cell line. The new method is both embryo- and woman-friendly.

But is it really true that the ethical problems associated with research on human embryonic stem cells are now behind us?

The existence of the new stem cell technique doesn’t mean that scientists will simply abandon the use of embryonic stem cells. Until the new technique is sufficiently refined, scientists will still need to use the old methods. The new technique, in its current form, requires genetic engineering that results in permanent genetic changes. Until the new technique can be modified so that genetic modification isn’t necessary, the safety of the resulting cells for human therapeutics will be in question. Many scientists have cautioned that experimentation with the new technique will have to proceed alongside the older embryonic method for at least several years. The reported end of the ethical questions associated with human embryonic stem cell research is thus something of an exaggeration.

Also raising a new set of ethical questions is the reprogramming technique.

Ordinary skin cells, since they are genetically identical to their donor, will carry information about the donor’s genetic identity. This gives rise to ethical and legal questions about the donor’s privacy rights. Legal and ethical issues also arise about the ownership of the donor’s genetic material.

What’s more, the new technique also uncovers ethical questions that have been overshadowed by concerns about the moral status of the human embryo. One such question concerns the appropriate limits on experiments with grafting or mixing human and animal cells, such as placing human neural cells into non-human brains. How can scientists best protect experimental subjects in early clinical trials from the inflated hopes generated by hyperactive media attention? Should the new technique prove effective, still other ethical questions will come to the fore: Who will have access to the novel drugs and therapies as they become available? How, as Bennett rightly asks, will we meet the challenge of ensuring that the poor and underinsured in California (and elsewhere) have access to therapies and drugs developed with public money? How will we manage the social consequences of longer, healthier lives?

Historically, new technologies very seldom solve ethical questions; they just give rise to fresh ones. But this isn’t altogether a bad thing. With the concerns about the moral status of the embryo put to rest, the new reprogramming method of producing stem cells will allow the national conversation to take up a wider range of ethical issues surrounding the issue. As hopes for stem cell therapies become clinical realities, these issues become critically important, and now is the time for us to start talking about them.

Mary Devereaux, Ph.D. is a fellow at the San Diego Center for Ethics and member of the UC San Diego Research Ethics Program. You can contact her at

Jeanne F. Loring, Ph.D. is the director of the Center for Regenerative Medicine at Scripps Research Institute in La Jolla. You can contact her at

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