The Stem-Cell Controversy Continues

My colleague Phil Gaspar recently forwarded  a collumn by Arthur Caplan of the University of Pennsylvania Center for Bioethics to me on the ongoing issues related to stem-cell research, attacking the recent breakthroughs in obtaining those cells without destroying embryos. An excerpt:

Lanza’s current research involves pulling cells known as blastomeres out of human embryos. He took a human embryo in a lab dish to the eight-cell stage of development and took off a single cell. Then he reported growing stem cells from that single cell. Lanza declared that “this removes the last rational reason for opposing” embryonic stem cell research.

But does producing stem cells from blastomeres give us a chance to reach consensus on the ethics of embryonic stem cell research? Hardly.

First, it is not at all certain that the cells grown from embryos at the eight-cell stage of development are exactly the same and just as potent as those taken from a two-day old embryo. If not, they won’t be as useful to medical researchers.

Second, in pulling off a cell this early in embryonic development, some critics of research on embryos are going to oppose Lanza’s idea either because you are putting an embryo at risk or because it is still possible that twinning could have occurred and so each of the blastomere cells need to be treated as potential people and thus not destroyed.

Third, who exactly is going to offer up their embryos for this sort of a biopsy? Not couples who just are trying to have babies since they won’t want anyone lopping cells off their embryos no matter how reassuring the scientists who want them might be that it is safe to do. And if the blastomeres come from embryos being tested for diseases as is done in some clinics — a process known as preimplantation diagnosis — then who is going to want to grow stem cell lines from genetically diseased source cells?

Finally, and most importantly, in order to get at blastomeres you still need to create embryos at infertility clinics. When you do that, you will always wind up with more embryos than you need because we still aren't that good at producing them in the lab. This means there will always be surplus embryos, which will either be frozen or destroyed.

Ultimately this so-called "breakthrough" does little to quiet the critics of embryo destruction or the proponents of stem cell research using human embryos, such as myself, since why not use the unwanted extra embryos rather than going through the rigmarole of pulling cells out of those that make it to the eight-cell stage?

Today, Ron Green of Dartmouth University replied to Phil, who again passed it on. Another excerpt (below the fold):

Caplan asks "if the blastomeres come from embryos being tested for diseases as is done in some clinics - a process known as preimplantation diagnosis - then who is going to want to grow stem cell lines from genetically diseased source cells?" This is a genuinely ignorant remark. In Preimplantation Genetic Diagnosis, on average, half of the embryos test negative for the familial mutation. This means that there is an ample source of healthy embryos--embryos from which a blastomere must be removed for the PGD procedure--that can each supply a cell for stem cell derivation. (Cells from affected embryos can be used to make very valuable model disease lines.) Since these are families seriously affected by disease, since the cell derivation procedure can be based on the same single cell (grown out) used for the PGD, and since the resulting stem cell lines will be immunologically compatible with and beneficial for each embryo that implants, there is every reason
to believe that hundreds of the thousands of PGD couples will cooperate with this research.

I could repeat this analysis of virtually everything Caplan says. In his role as public bioethicist, he sometimes speaks before he examines the issues. This is one example.

He also refers us to his testimony on the issue at website of the California Stem Cell Report:

Dr. Lanza has also shown that the extracted individual cells cannot reasonably be regarded as individual or independent human beings. No cells extracted at this stage of embryonic growth could go on to full term development.

There are two remaining ethical concerns that I would like to address. First, there is the connection between this new method and both IVF and preimplantation genetic diagnosis (PGD). Some people object to both these technologies because they involve the manipulation of embryos and because parents using these procedures can elect not to implant some of the embryos produced in this way. But this objection is made by only a small minority. The overwhelming majority of Americans support both procedures. IVF helps infertile couples have children and PGD allows those who carry dread genetic diseases to have healthy children. Both procedures help people have children that otherwise would never have been conceived or born. In this respect, both are profoundly “pro-life.”

Second, there is the concern that the embryos used in this research did not survive the experiment. Since the publication of the Nature report some critics have emphasized this fact even though it remains true that the method developed by ACT scientists requires no further destruction of any embryos. I would like to point out that because this research was privately funded, this experiment was legal. It was also approved by ACT’s Ethics Advisory Board and by an additional institutional review board that was mandated under Massachusetts law. The embryos used were donated by people who had fully consented to the research and understood, and even required, that the embryos would not be allowed to go on to further development.
It is not unique that the initial research needed to develop morally acceptable methods or materials do not meet everyone’s approval, but this does not impugn the methods or materials produced as a result of that research. One example is the polio vaccines we use today. Some of the initial research on these vaccines was conducted with a technique that required the use of tissues from aborted fetuses. Later, this approach was replaced by other methods.

Almost no one today refuses polio vaccination for their children on the grounds that they object to the methods used in the first experiments. I would point out that even President Bush has been willing to use the harmless downstream results of research to which he objects. All of the stem cell lines being used in federally funded research today were produced by embryos that were destroyed for this purpose before the President’s August 2001 directive. The President could have said that none of these lines should be used because they were created in a way he regards as morally objectionable. But he did not. He concluded that so long as no future harm is done, this valuable resource could be used.

Thanks to this research breakthrough, we are in exactly the same position today. If Congress were to approve legislation that funded research on lines generated by this new method, and if President Bush were to permit such legislation to pass into law, both the members of Congress and the President could honestly turn to the American people and say that no human embryo ever again needs to be harmed or destroyed to produce the stem cell lines we need for federally funded research.

Many scientists believe that we need several hundred new federally funded stem cell lines in order to have the genetic diversity needed for research. Well over 2,000 PGD procedures are conducted in this country each year. If just one out of three of the couples using this procedure authorized the harmless derivation of a cell line from the extracted cell of each of the embryos they chose to implant, we could produce at least fifty new cell lines every year from now on. The derivation of these cell lines would cause no harm to any of the donor embryos, a fact of critical importance for both the ethical and legal authorization of this research.

As I've said before, we're reaching the stage where the only people who will remain opposed to this research are the hard core of folks who think that you should never do anything to any embryo ever. When the potential benefits of this research are set against the possibilities of harm to embryos, this faction will shrink to a smaller and smaller fringe of the moral world. Unfortunately, that fringe currently has a great deal of power in Washington, D.C., including the Presidency of the United States.

For now, the moral issue will continue to be hashed out where they should be -- among scientists and ethicists who are genuinely struggling to find a way through the moral complexities that this research evokes. When the stem-cell obstructionists are finally reduced to ranting from soapboxes in central part, instead of from prestigeous bioethics centers, we'll all be better off.