Embryonic stem cells

Recent reports of scientists creating "ethical" embryonic stem cells are false or misleading. And there is reason to be very concerned.

Forbes described it as a "medical milestone" and a scientific "breakthrough" with a headline "Scientists Harvest Stem Cells Without Destroying Embryo," while the Washington Post headline read "New Method Makes Embryo-Safe Stem Cells." "Firm makes ‘ethical’ embryo stem cells" was the headline from Reuters . The BBC ran with "’Ethical’ stem cell lines created" and a blurb stating, "Human embryonic stem cell lines have been generated without embryos being destroyed, according to researchers." But this isn’t quite right: As the original report in Nature and their accompanying news coverage make clear, the researchers did, in fact, destroy many human embryos in the process of creating these stem-cell lines. This, of course, belies the content of the headlines and also calls into question the ethical reliability of those involved in this research project.

The report is significant, though, since researchers produced stem-cell lines from cells removed from the human embryo at the 8-cell stage. Previously, all embryonic stem-cell lines were produced from cells in the embryo at the subsequent blastocyst stage. Removing cells from the embryo at this later stage kills the embryo that is dismembered in this process. Now, however, researchers are hopeful that they can remove a cell from a human embryo at an earlier stage of development without killing the embryo from whom that cell is removed, and still create a new stem-cell line. Furthermore¯and this is their crucial ethical argument¯cells are already being removed (sometimes) from 8-cell stage IVF embryos for preimplantation genetic diagnosis (to test for genetic diseases), and these embryos are then implanted and show no signs of deformity. Or so their argument goes.

In essence, the new report says that a single cell can be removed from an embryo at the 8-cell stage, and the remaining 7-celled embryo will continue to develop unaffected. The single cell removed would then be cultured to produce embryonic stem cells. Everyone is a winner.

But not so fast. For this "new" report isn’t really new at all. In fact, when first proposed it was soundly rejected. The President’s Council on Bioethics unanimously rejected this very proposal one year ago in its white paper Alternative Sources of Human Pluripotent Stem Cells . The council concluded that it would be unethical to perform this procedure on human embryos because the potential for harm posed "by embryo biopsy and blastomere removal on a born child the embryo might become [are] solely for research [to benefit others and] of no benefit to him or her." The council concluded that tests could be performed on animals, but they did not see "how results from animal experimentation could alter this assessment of ethical propriety in humans." In sum, there is the possibility for risk to the mature human being resulting from cell removal during the embryonic stage of his or her life. And the only way ever to know how much harm this may cause in humans would be to test it on humans . Subjecting any human being to that unknown risk via research would be unacceptable. And so the council¯some of whom do not believe that the early human embryo merits full moral status¯unanimously rejected this proposal one year ago.

Yet there are other reasons not only to be reserved in one’s enthusiasm for yesterday’s report but also to be disturbed.

First, the single cell removed from the 8-cell embryo might be totipotent, i.e., capable of actively developing itself (once separated) into a mature human. But if that is so, then this single cell, once separated, is now a whole human embryo itself. Just as the natural phenomenon of monozygotic twining occurs when a single cell breaks off from the early embryo and goes on to develop into the next, more mature stage of the human being, so too might a single cell when artificially removed. In effect, the proposed procedure might be artificially producing a twin and then treating it as a stem cell or a progenitor of a stem cell. Hence, this proposal would ethically be no different from other forms of embryo destruction.

Second, where will scientists obtain the embryos to use for this research? This research will require thousands of human embryos, and IVF "spares" will not be sufficient. Furthermore, what will happen with the 7-cell embryos after biopsy? Will they remain perpetually frozen, or will they all be implanted? Of course, this raises questions about the entire Artificial Reproduction Technologies (ART) industry. ART is currently largely unregulated, allowing technicians to create as many embryonic human beings as they wish, and then freeze, discard, or implant whatever proportion they choose. Thus, if human beings in the embryonic stage are deliberately created via IVF for this procedure, what will be their fate? Will they be transferred to a womb, left in a suspended state in a freezer, or discarded with the trash?

Third, to a certain extent the entire discussion of IVF "spares" (or the intentional creation of IVF embryos for research) is a distraction from what embryonic stem-cell researchers really want: cloned human embryos. Why? Because a cloned human embryo will have the same genotype as the adult from which it was cloned. Thus, all the stem-cell lines created from this cloned embryo would be exempt from one of the major hurdles of all modern medical therapies: immune rejection. To make stem-cell therapies work, physicians will need to create stem-cell lines with the same genotype as the patient they are trying to cure. This, of course, could only be accomplished by means of the creation of a cloned embryo. (Of course adult stem-cell therapies avoid immune rejection because they are taken directly from the patient in need of treatment.)

But there is another option: the direct creation of pluripotent (embryonic-type) stem cells without the creation, use, or destruction of any human embryo. There are currently two proposals on the table to accomplish just this. The first procedure, proposed by William Hurlbut (professor of neurological science at Stanford), is known as Altered Nuclear Transfer Oocyte Assisted Reprogramming (ANT-OAR). Garnering broad support both from the scientific community (such as heavyweight stem-cell researcher Markus Grompe, director of the Oregon Stem Cell Center and a member of the board of the International Society for Stem Cell Research) and from the pro-life and Catholic communities , many see it as the best path (in addition to the highly successful adult stem-cell therapies) moving forward. ANT-OAR is a technological means of directly creating an embryonic stem cell through the fusion of an altered somatic cell nucleus and an enucleated ovum. The ovum’s cytoplasm causes the epigenetic reprogramming of the somatic cell, returning it to a pluripotent state, while the alteration of the somatic cell’s nucleus prior to transfer prevents it from being reprogrammed beyond the pluripotent state to a totipotent state, i.e., into a human embryo. Hence, no embryo is created, no embryo is destroyed. To read more about the technique, see here and here .

The second proposal relies upon dedifferentiation (reprogramming) of an adult somatic cell back to a state of pluripotency. As the human being matures, his or her cells differentiate as they become highly specialized tissue types. Scientists are now working to dedifferentiate these adult cells and return them to a state prior to specialization. This procedure is much like ANT-OAR, but seeks to reprogram a somatic cell without any nuclear transfer and thus without need for any ova. Further research into both of these procedures should be met with broad support.

In the end, the scientific community must affirm its commitment to search for cures while also respecting the innate dignity not only of the people they seek to help but also of all human beings, at whatever stage of their development. Only stem-cell research (and all other research) proposals that treat the embryonic human being as a subject of full moral worth can succeed.