Posted on 07/08/2009 7:40:47 PM PDT by neverdem
Less than two years ago, it looked like the ethical debate over human embryonic stem cells might be coming to an end. In November 2007, two research groups, one at the University of Wisconsin-Madison and another at Kyoto University in Japan, announced that they had succeeded in directly reprogramming human skin cells into stem cells. Earlier this year, Canadian and British researchers reported even better news. They have developed a new way to create such cells without using viruses, which pose a risk of producing tumors by damaging the transformed cells' genes.
Yesterday, as many as 700 new stem cell lines were approved for use in federally funded research by the National Institutes of Health, reversing the policy of the George W. Bush administration to restrict funding to just a handful of approved cell lines on ethical grounds.
With the new stem cell lines comes a new round in the debate over cells and souls. "These guidelines encourage researchers to go out and destroy embryos for taxpayer-funded research," Richard Doerflinger of the U.S. Conference of Catholic Bishops told The Washington Post. "You and I were once human embryos, and each embryo has the inherent potential to grow into you and me."
Stem cells derived from skin cells sidestep the ethical concerns that some people have about destroying embryos to produce stem cells because they supposedly cannot develop into human fetuses, much less full-term babies. But is that so? In 2007, a team of researchers led by Massachusetts Institute of Technology biologist Rudolf Jaenisch showed that stem cells from mouse skin cells—induced pluripotent stem cells (iPSCs)—could be grown into mouse embryos. The team achieved this feat by injecting stem cells produced from mouse skin into special tetraploid blastocysts which can produce only placental tissue. Tetraploid blastocysts are produced by jamming mouse zygotes together so that they join to create cells that have twice the DNA of normal cells. The pre-implantation embryos composed of tetraploid cells and iPSCs can develop to term after being transferred into the womb of a surrogate mother. In other words, mouse skin cells can be transformed into mouse embryos. There is no reason to believe that this would not also work for human skin cells.
This development has prompted a biologist and a bioethicist to take on the argument that the "natural potentiality" of human embryos to develop themselves means that they must be accorded the full moral respect we give to adult human beings. As Duquesne University bioethicist Gerard Magill and Stowers Institute for Medical Research president and biologist William Neaves assert in the March 2009 issue of The Kennedy Institute of Ethics Journal (subscription required), "a reprogrammed human cell is not fundamentally different from a nuclear-transfer or natural fertilization zygote in its ability to become a fetus."
They acknowledge that a conventionally produced or cloned zygote makes its own placenta while the reprogrammed skin cells must be provided one. Is that enough to make a difference in the cells' moral status? Magill and Neaves don't think so. They point out that placental cells need signals from embryonic cells in order for a placenta to develop as well. Magill and Neaves go on to speculate about the possibility of using direct reprogramming to create induced totipotent stem cells from skin cells. In this case, the reprogrammed skin cells would have the capacity, if installed in a womb, to produce all embryonic stem cell lineages including placental cells.
Magill and Neaves conclude that the fact that ordinary body cells can be transformed into embryos argues against according a special moral status to early stage embryos, describing them as "matter that is inadequate for the so-called form of human personhood."
Naturally their argument has opponents. In the same journal issue, University of Utah neurobiologist Maureen Condic, Franciscan University of Steubenville bioethicist Patrick Lee, and Princeton University professor of jurisprudence Robert George claim that the details of biology of embryos and iPSCs make all the moral difference. Specifically, they assert that stem cells and iPSCs "will participate in embryonic development if they are injected into an embryo that is incapable of forming [an inner cell mass]." What can they mean by "injected into an embryo"? Are Condic, Lee, and George calling a tetraploid blastocyst—a group of cells that can only become placental tissue—an embryo? It is a very odd kind of "embryo" that can only form placental tissue, which is not tissue that can grow into a body.
The ethical analysis offered by Condic, Lee, and George turns chiefly on the question of whether or not a placenta is "a component of a supportive environment or a component of the embryo." They argue that Magill and Neaves are wrong to say that a "zygote makes its own placenta, while the reprogrammed skin cell must be provided with one, but the placenta never becomes part of the embryo itself." On their view, the fact that a regular zygote (conventionally produced or cloned) can produce the cells that make a placenta is ethically decisive.
If this is so, then it would seem that Condic, Lee, and George must be committed, at least, to the idea that an entity comprised of a tetraploid blastocyst and reprogrammed human skin cells must be the moral equivalent of a conventionally produced embryo—that is, the human equivalent of the mouse embryo produced by the MIT biologists.
Condic, Lee, and George apparently take their final stand when they argue that totipotency, the ability to produce both body cells and placental cells, requires the regulatory molecules in egg cytoplasm. "The oocyte is not simply a source of generic, chemical 'reprogramming factors,' it is a highly structured cell with unique material composition and a unique organization of these components—all of which are required for totipotency."
Perhaps Condic, Lee, and George are right. Maybe true induced totipotent* stem cells are impossible and it will always take the regulatory factors in human eggs to produce viable conventional, cloned, or iPSC human embryos. But do they really want to bet against researchers figuring out what those regulatory factors are and then using them to reprogram skin cells? Back in 1997, it was settled scientific doctrine that mammals could never be cloned; then along came a sheep named Dolly. In fact, Condic, Lee, and George may be wrong when they assert that human stem cells and iPSCs cannot make placental cells. Current data do not rule out the possibility that stem cells and iPSCs may be totipotent.
If it turns out that it is possible to reprogram skin cells directly into complete embryos, one can hope that the increasingly desperate and convoluted arguments against human embryonic stem cell research made by Condic, Lee, George, and other opponents will finally collapse.
As our biological knowledge and prowess increase, it is likely that opponents of stem cell research will one day be relegated to claiming that the moral status of a human cell depends on how a single molecule is positioned on a strand of DNA. More moral insight might be garnered from arguments about how many angels can dance on the head of a pin.
CORRECTION: Condic, Lee, and George are skeptical of the possibility of true induced totipotent stem cells, not true induced pluripotent stem cells.
Ronald Bailey is Reason magazine's science correspondent.
stem cell ping!
Do skin cells have soul?
Just the ones with lots of melanin.
I’ve been trying to point this out for several years on FR. Yes, “adult” stem cells have tremendous potential, but much of that potential can come only after they’ve been converted into embryonic stem cells, which are just as capable of turning into full blown organisms as a embryo created from a sperm and an egg. It’s only a matter of time — and apparently not much more time — before this process is perfected.
God wants his children to grow up. Deal with it.
WOW! Intriguing!
Just the ones with lots of melanin.
Dark humor.
LOL. Melanin. That made my night.
You presume to know the mind of God (”God wants ...”), but you can’t help the smarmy jibes (”Deal with it”). True to your usual form, GS. Even a good stiff drink wouldn’t help the bitterness festering inside of you.
BTT
Cong. Report Says Government Caused Financial Crisis; Sessions' Questions on Sotomayor
Ward Churchill smack down by courts
Some noteworthy articles about politics, foreign or military affairs, IMHO, FReepmail me if you want on or off my list.
The writer lost control of the discussion by calling everything a "stem cell".
Bailey is definitely not “better than ever.” Unless it’s at clouding the argument with straw men and what appears to be deliberate obfuscation, as in muawiyah’s example of blurring the lines between “embryonic stem cells” and “stem cells.”
A blastocyst, by definition, is an embryo. Bailey should know that. While the tetraploid blastocyst is not a normal embryo, it is an embryo.
The International Society of Stem Cell Researchers glossary:
http://www.isscr.org/glossary/index.htm#blastocyst
If you’ve been paying attention, the functions of the stem cells that we’ve been looking for are only found in cells that are differentiated to a certain degree.
In the meantime, Shrinker, embryonic stem cells are not “totipotent,” in that they can’t form the placenta.
Purposeful, technical acts are required to produce the blastocyst and inject the induced embryonic-like stem cells. It would take different, even more technical purposeful acts to produce a truly “totipotent” stem cell ine capable of forming an embryo from skin cells.
This experiment is gross and inelegant experimentation - rather like a teenager using an icepick to gig a frog on the side of the riverbank just to see it die: Completely unnecessary and without merit, as well as immoral.
It’s easy enough to decide not to create and destroy human embryos, not to clone human embryos, and not to implant human stem cells into human embryos (either
. . . (either normal or abnormal).
Thanks for the ping!
Does anyone have a problem with creating embryonic stem cells? The problem most have is with destroying such already existing cells which have the capability to continue to thrive and become a human.
The embryo is already a human. The embryo is an organism, not a subunit of same. The methodology being experimented with will fabricate a human, an organism. Embryo is an age in the lifetime begun at conception of an organism, by whatever means.
Thanks for the link!
The point is that we’re fast approaching the point where ALL types of stem cells will have the capability to “continue to thrive and become human” — including those taken from the blood or skin or marrow of an adult human and nudged back to totipotency. And nudging back to totipotency is the only way to get stem cells that are not embryonic in origin to fulfill all the therapeutic potential of stem cells. Once you’ve taken an adult stem cell back to where it can differentiate into a heart or a kidney or a brain or a spinal cord or an eye, it can also differentiate into *all* those things in the form of complete new organism. Are we then going to have the religious objectors to embryonic stem cell research/therapy start howling in protest against adult stem cell research/therapy?
Well the, can we have your liver?
I might give you part of it if you really needed it. But you’d really be much better off having one grown from your own stem cells, that had been reverted to embryonic stem cells, that *could* have become a baby clone of yourself, but were instead tampered with to become only a new liver for you. Genetic match, so no need to take anti-rejection drugs for the rest of your life. This is where things are headed, so you need to start thinking about whether you’re going to regard stem cells that were taken from your body as “babies” just because the lab has reverted them to totipotency so that they *could* become babies.
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