Google+
Close
The Real Good News on Stem Cells
Beyond the hype, some real hope.


Text  


A stem-cell study published in the journal Nature last week set off a media frenzy. Headlines in all the major newspapers promised pluripotent (i.e., embryonic or embryonic-type) stem cells without the destruction of embryos. That’s what many people on both sides of the debate over embryo-destructive stem-cell research had been hoping for. But, alas, it turned out to be all hype.

Advertisement
Nevertheless, the general story of which it forms just one small part — the story of emerging techniques to derive embryonic-like stem cells without harming embryos — may well turn out to be the scientific (and perhaps the political) good news story of the year. Some of headlines may turn out to have been right, even if the details they provided for this particular effort turned out to be all wrong.

The specific story as recounted in the press was roughly this: Researchers were able to remove a single cell from a living human embryo without destroying that embryo. The single cell was then developed in culture into an embryonic stem cell. Since the removal of single cells from eight-cell embryos is a regular practice in some assisted-reproduction clinics (as part of a process of screening embryos for genetic abnormalities), this could be done routinely without harming human embryos and could allow for new stem cell lines with no ethical problems.

But it turned out not to be true. First, the study did not involve the removal of one cell from an embryo that then continued to develop. Instead, researchers disaggregated 16 living embryos, killing them all, and took an average of six cells from each. The 91 resulting embryonic cells were then placed near one another in dishes and allowed to divide. Some divided, while others died, and from the cells that divided researchers were able to produce two lines of embryonic stem cells. In other words, the study did virtually nothing to prove the point that Advanced Cell Technology (the company that carried out the experiments) had argued in the press: that single cells removed from an early embryo and cultured by themselves can produce lines of embryonic stem cells.

So far as I am aware, only the Los Angeles Times took note of this little wrinkle in ACT’s heavily publicized tale, but even the Times didn’t pay it much heed. The paper noted: “Although the embryos were destroyed in this experiment, Lanza said it was not necessary to destroy the embryos for the procedure to work.” If it was not necessary, why did his team do it? Certainly they would have had a better story to tell if they hadn’t. In reality, the fact they had to resort to the technique they used, culturing numerous cells from the same embryo near each other on a dish, suggests they tried to use just single cells but failed. In other words, the ACT study did not show it is possible to extract a single cell from an eight-cell embryo and produce a line of stem cells.

Second, even if it were possible to derive stem cells this way, the notion that removing a single cell from a developing embryo has no negative effect upon the tiny human individual as he or she develops from the embryonic stage into and through the fetal, infant, child, and adolescent stages and into adulthood is at the very least unsupported. As I mentioned, such “blastomere biopsy” is sometimes done to perform genetic testing on IVF embryos. You won’t find it difficult to guess why. This “pre-implantation genetic diagnosis” is performed in a eugenic effort to “weed out” those found to be unfit because they are likely to suffer from genetic diseases. This is deeply troubling in itself.  More to the point for present purposes, however, is the fact that there have been essentially no studies on the health effects of cell removal on the children who began life as embryos subjected to blastomere biopsy. Some estimates suggest more than 1,000 children worldwide have been born following such a procedure, but there has been no longitudinal study of their health and well-being.

Dr. Andrew La Barbera, scientific director of the American Society for Reproductive Medicine, which represents doctors who conduct these kinds of biopsies on embryos, could give no greater assurance to the New York Times than that “there is no sign yet that they have any greater risk of disease than other in vitro fertilization babies, but the society needs more data to be sure.” Given that there have also been no efforts to look for signs, this is hardly comforting.

It is also not clear if cells removed from embryos at that very early stage do not themselves, when isolated, have the ability to develop as full individual embryos. The question here is whether embryo biopsy amounts to a form of induced identical twinning. That question, too, suggests the ethics of this proposed technique are very much in doubt.

ACT’s scientist-salesmen imprudently dismissed these concerns in the press, and hyped their findings. “There is no rational reason left to oppose this research,” Dr. Robert Lanza, ACT’s vice president told the New York Times. This was mere bravado. It did not, and will not, make serious questions go away.  Indeed, the media is now in full retreat from the original story, and reporters are not at all happy with ACT for having sold them a bill of goods.

Last year the President’s Council on Bioethics carefully considered embryo biopsy among other techniques for developing embryonic-like stem cells without doing harm to human embryos. The Council concluded decisively and (uncharacteristically for the quarrelsome group) unanimously that the technique described in this week’s publication could not be ethically pursued in humans. But the Council report also considered other possible ethically uncontroversial ways forward, and it is that larger picture — the emerging range of options for non-embryo-destructive means of producing pluripotent stem cells — that is the real story of the past year. It is a very positive story, and one that seems increasingly likely to put our troubling societal division over stem cells behind us.

After all, what really stands out about the ACT study is its fundamental aim. Stem-cell researchers are recognizing the need to find ways of doing their work that do not involve the destruction of human embryos. This is truly a welcome development.

Those of us who defend embryonic human life have vigorously supported non-embryo-destructive methods of obtaining pluripotent cells. We are not opposed to stem-cell research, or even embryonic-stem-cell research, as such. We are opposed only to practices that harm or destroy human embryos — who are, as all the leading works of modern embryology attest, human individuals at the earliest stage of development. If research did not require the destruction or exploitation of human embryos, we would be fully prepared to support it.

President Bush and a huge bipartisan majority in Congress have also voiced support for ethically unproblematic ways forward. “Researchers are investigating new techniques that might allow doctors and scientists to produce stem cells just as versatile as those derived from human embryos without harming life,” the president said last month, “we must continue to explore these hopeful alternatives, so we can advance the cause of scientific research while staying true to the ideals of a decent and humane society.” Also last month, the Senate passed a bill that would provide funds for research that sought the same kinds of cells now derived from human embryos, but without requiring the use of such embryos. Support for this bill came from both parties and from across the ideological spectrum from Sam Brownback to Edward Kennedy. The vote was unanimous. It garnered a large majority in the House too, but (due to the spite and deceptive last-minute tactics of a small minority of House members) not the two thirds needed to pass it under the governing rule. So President Bush has said his administration will take what actions it can on its own initiative to promote such promising ethical avenues of science.

Despite the exposure of the ACT research as pure hype, it is increasingly clear that such sources are coming. One possibility is “altered nuclear transfer.” This research, being pursued at MIT and elsewhere, seeks to fuse ordinary body cells, obtained harmlessly from donors, with oocyte cytoplasm in such a way as to produce donor-specific pluripotent stem cells without producing or destroying a human embryo. Another possibility is “dedifferentiation.” Last August, Harvard scientists showed they could “reprogram” an ordinary human skin cell back to the pluripotent state. No embryo was produced in the process, yet stem cells were generated. Their experiment still has some kinks to clear away, but just a few weeks ago a group of Japanese scientists showed they could eliminate many of those and turn a skin cell into the precise equivalent of an embryonic stem cell. Their work was in mice, and perhaps that is why it did not receive the degree of attention that the ACT study grabbed, but it was if anything more promising and exciting — and would have been even if the ACT study had been what the ACT publicity machine had cracked it up to be.

Similar techniques are being explored around the world, and it now seems that a new mood is overtaking the field. If nothing else, the work of the ACT scientists implicitly acknowledges the need to find sources of stem cells that do not require embryo destruction. This acknowledgement by stem cell scientists, met as it has been by support and encouragement from the president, Congress, and with last week’s flurry of news also the general public, points the way out of a needless controversy over stem-cell research, and toward scientific promise all Americans can support.

The real news, then, is not about one grossly hyped study published by a publicity-hungry biotech firm. Rather, it is about the promise that pluripotent-stem-cell science can proceed without human embryo-killing. It is very good news.

 – Robert P. George is McCormick Professor of Jurisprudence and director of the James Madison Program in American Ideals and Institutions at Princeton. George serves on the President’s Council on Bioethics.



Text