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.
Once again, embryonic stem cells come from the inner cell mass of the blastocyst. They are differentiated and no longer “totipotent.” They are pluripotent, but cannot form the placenta.
After “disassembly” from the intact organism, the embryo, they are not, themselves, an organism or able to form an organism, without interference (by placing into an embryo). The organism (embryo) will develop along a purposeful, organized course if in a hospitable environment. The embryonic stem cells which have been removed from the embryo become teratomas, not body parts, not recognizable, organized and functional bodies.
Furthermore, it is not actually necessary to begin at the embryonic stage of the cell to grow organs, tissues or specialized cells. In fact, the cells actually specialize and function *only in the proper environment for that cell.*
There was actually a report the other day about the regeneration of limbs in amphibians. The regeneration does not require or utilize embryonic stem cells.
It makes sense that what we want are the partially differentiated cells for each line or even more differentiated precursor cells. There’s less risk of any cells developing into an undesired type of cell this way.
Not necessarily. A couple of years ago, there was a study published re stem cells derived from pre-blastocyst embryos. The main purpose was to show that embryonic stem cells could be obtained without destroying the embryo, using essentially the same technique that is used for PGD, i.e. plucking cells at around the 8 cell stage. The embryo continues to develop normally, and the stem cells are thoroughly totipotent at that point. Obviously the stem cells which would ultimately be used for treatments need to first differentiate to become the inner cell mass of a blastocyst, because that’s a step on the way to becoming all the parts of a fully developed organism (though theoretically, at least, some treatment might be eventually be pursued for which either a whole replacement placenta or certain placental cells would be needed — probably some sort of in utero treatment for developing fetuses).
It’s likely, however, that certain organs we want to grow from inner cell mass stem cells can only be grown if something like a placenta is also present, e.g. to grow a fully functioning heart or kidney, which is simply not going to happen with a free floating cell mass in a beaker, no matter what chemical tricks are played on it. As you pointed out, the inner cell mass stem cells need to be in the right environment to differentiate into the normal set of structures. In some cases, the right environment may be found inside the body of the patient, but even that may require starting with some outer cell mass stem cells, in addition to the inner cell mass stem cells, in order establish the connection to the blood supply. And if the patient’s condition is so poor due to the loss of organ function, the patient’s body may not be a hospitable environment capable of supporting development of a healthy new organ.
We do indeed ultimately want partially differentiated stem cells, but *all* kinds of partially differentiated stem cells. Only certain types of differentiated stem cells are found in a fully developed organism; to get the others requires stem cells that are from a much earlier stage, and for certain types, all the way back to the embryonic stage.
And you have conveniently left out of your calculus the fact that researchers are showing success at 'backing up adult stem cells' to a less differentiated state where these stem cells can then go forward along cardiac or other tissue lines different from where they were drawn. Is that sort of success to be set aside because you want to harangue religious beliefs via emrbyonic stem cell ethical issues? From the cut of your postings, I'd say the latter is your agenda, not the former.
Being quite religious myself, I don’t have any “hatred of religious folk”. But not all religious beliefs are the same. My God wants his children to grow up, not to remain forever helpless infants, leaving everything important up to Big Daddy God.
Various (but probably not all) tissue types can be generated from partially differentiated stem cells, and it’s very doubtful that most complete organs could be generated that way. If stem cells are produced by “backing up” from adult cells, it’s not at all clear that those cells belong to a different individual than the one who provided the starting cells. When people start claiming that full rights as a human person should be accorded to cells that were converted/reverted from a few cells taken from an adult person, that’s getting pretty extreme and impractical.
Do you even know precisely what is an embryo?
Yes, I know what an embryo is. Just because someone disagrees with you doesn’t mean they’re ignorant.
And we have ythis little piece of herring you tried to float: "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." And of course you realize that is a specious assertion, but you made it anyway! ... You do understand why your assertion is false, don't you?
It’s not a “specious assertion”. It’s a near certainty that this will be feasible within the next few years. Embryonic stem cells routinely develop into complete organisms — that’s how each of the billions of people on this planet got here. And the technology to revert stem cells taken from fully developed organisms back to the same condition as embryonic stem cells is very advanced already, and very close to being all the way there.
Per usual,
those who want to destroy one human (embryo) to potentially save another,
conflate “stem cells” with “embryonic stem cells”.
This by you is very inaccurate yet you choose to characterize it as accurate: “... it can also differentiate into *all* those things in the form of complete new organism.” I didn’t realize you were prone to such deceit, even trying to mischaracterize your own words now!
There is no conflating.
Embryonic stem cells have characteristics that enable them to differentiate into an entire new organism, with all the component cell types, tissue types, and organs.
Any stem cells which have been processed so as to have all the characteristics of embryonic stem cells will have the same differentiating abilities as stem cells which started out as embryonic stem cells.
Any stem cells which do not have all the characteristics of embryonic stem cells are limited as to what kinds of cells, tissues, and organs they can differentiate into.
Since you have no interest in science, but only seek to twist it to support your preferred conclusions, I don’t see the point of discussing it with you further. It’s like trying to use scientific information to convince Al Gore that life on Earth isn’t on the verge of being destroyed by human-caused global warming. Al has decided that human-caused global warming is going to have catastrophic results, and he will dismiss any information to the contrary as “deception” perpetrated by people who have some mysterious agenda that requires continuing on a course to global catastrophe. You and Al have a lot in common.
I dare say I comprehend the science at least as well as a liberal doofus like you who plays semantic games to try and cover his ignorance. I have online a little book I wrote which explains embryonic stem cells and the concepts of stem cells, etc. as related to cloning and abortion tissue harvesting, if you really need help. I wrote it for the layperson, even liberals like you.
[http://weneedtalk.blogspot.com is the e-addy, from whence you may click on the html of PDF format and download any or all of it. If you have any questions while reading the little book or consulting the glossary therewith, you know where you can find me.]
BTW, do you even know that the ability to produce a placental cell line is also one of the characteristics of totipotent stem cells? That's why a cell can be removed from in vitro embryos, to do genetic testing, without killing the embryo. The removal must be done before placental differentiation begins, to prevent killing the embryo. But I doubt the killing of an embryo to obtain stem cells even registers in your dark heart.
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