Posted on 05/13/2008 2:48:10 PM PDT by neverdem
Until about a decade ago, there was only one way to make an embryo—the old-fashioned technique of combining an egg with a sperm. Then came Dolly the cloned sheep in 1996. Scottish scientists created her by injecting the nucleus of a breast cell from one sheep into the enucleated egg of another sheep. Dolly was essentially genetically identical to the donor of the breast cell nucleus.
Since then researchers have used reproductive cloning to produce mice, cats, dogs, horses, cows, goats, pigs, and other mammals. As valuable as reproductive cloning is for producing livestock and research animals, most researchers were excited by the prospect of using cloning to create human embryonic stem cells. These stem cells produced by therapeutic cloning might be used to grow perfect transplants to replace and repair damaged tissues and organs.
Therapeutic cloning to produce transplants fell directly into the heated abortion debate. From the pro-life point of view, cloned human embryos, like all other embryos, have the same moral status as adult human beings. The moral status of five-day embryos is still contested. Hoping to avoid controversy, researchers searched for sources of cells that would have the valuable properties of embryonic stem cells (self-renewing and transformable into any type of cell), but would be acceptable to pro-lifers.
One proposal is to create human stem cells using altered nuclear transfer (ANT). Championed by Stanford University bioethicist William Hurlbut, the technique is essentially the same as regular cloning except that it uses RNA interference to disable a single crucial gene so that the cloned entity cannot implant into a womb and thus cannot grow into a fully developed embryo. In ANT all of the genes involved would be human, even the one that has been deliberately broken.
A number of prominent Roman Catholic thinkers recently endorsed ANT as a morally acceptable way to produce human embryonic stem cells. So whether or not an entity can house a human soul evidently depends on the timing of the operation of a single gene. Other theologians question this, asking why such a cloned entity should not be considered a defective human embryo deserving of same the moral solicitude owed to disabled adult human beings.
The search for a morally unproblematic source of stem cells continued. Last fall, Shinya Yamanaka and his colleagues at Kyoto University in Japan and another team at the University of Wisconsin announced the good news that they had been able to transform adult human skin cells into cells that act very much like embryonic stem cells. Yamanaka took skin cells and inserted four genes—Oct4, Sox2, Klf4 and Myc—that are expressed in embryonic stem cells, causing the skin cells to revert to the embryonic state. These induced pluripotent stem (iPS) cells are generating a huge amount of excitement among stem researchers and were even hailed as the end of the stem cell wars.
Well, not quite. The Kyoto and Wisconsin researchers used skin cells originally derived from human fetuses in their research. Still, such cells are not necessary to generate new iPS cells; they were just convenient. But let's approach the moral issue from another direction.
It turns out that, at least in mice, injecting iPS cells into mouse blastocysts creates chimeric mice. The iPS cells are incorporated into the developing mouse embryo and form part of the tissues and organs of new mouse pups. Researchers at the Whitehead Institute in Massachusetts have gone even further. They created a mouse comprised entirely of iPS cells. The iPS cells form an embryo after they are embedded into tetraploid embryonic cells that grow into a placenta. There is no apparent reason why this technique wouldn't work in humans.
In April, this insight caused The Independent to hyperventilate, "Now we have the technology that can make a cloned child." The Independent quotes stem cell researchers Robert Lanza: "It raises the same issues as reproductive cloning and although the technology for reproductive cloning in humans doesn't exist, with this breakthrough we now have a working technology whereby anyone, young or old, fertile or infertile, straight or gay can pass on their genes to a child by using just a few skin cells." Maybe so, but iPS cell research raises an even more intriguing question.
Back in 1999, during a hearing of the National Bioethics Advisory Commission, then-Director of the National Institutes of Health Harold Varmus made the intriguing observation that "It may eventually become possible to take a cell from any one of our organs and to expose it to the right set of environmental stimuli and to encourage that cell to return to a more primitive stage in the hierarchy of stem cells. Under those conditions, one might in fact generate the cell with as great a potential as a pluripotent cell from a very mature cell." Nine years later Yamanaka proved that Varmus was prophetic.
Varmus continued, "One might even in fact imagine generating a cell that is totipotent [able to develop into a complete organism] in that manner." In other words, researchers may one day take human cells all the way back to the embryonic stage, at which point they could be implanted into a womb, where they could eventually develop into complete human beings. This is the direction in which iPS cell research is heading. So instead of switching off one gene to make sure that an entity is not worthy of their moral concern, pro-lifers may soon have to worry about the opposite, pushing an adult cell so far back in its developmental stage that switching on a single gene will turn it into an embryo.
Advances in stem cell research may be provoking a kind of "God of the Gaps" retreat on the moral status of embryos. People who subscribe to God of the Gaps thinking believe that the hand of God can be seen in those things which science cannot explain. In this case, the closing gaps in the details of molecular biology are forcing pro-lifers into an uncomfortable corner where they have to decide whether or not a cell can be imbued with a soul by turning a single gene on or off.
Ronald Bailey is reason's science correspondent.
People who subscribe to 'Naturalism of the Gaps' thinking believe that undiscovered natural processes can be invoked to resolve those things which science cannot explain.
stem cell ping
He’s certainly trying to be provocative, but I don’t believe they’ll be able to revert to a pristine, totipotent state of a brand new, diploid, fertilzed ovum, IMHO. Normal embryological development is only in one direction. Using extraneous RNA interference doesn’t qualify.
Let’s remove from the equation “when the soul becomes present”, let’s ask the atheists what the ethics are and when it should be considered an equal PERSON (or persons).
No reason we couldn't have folks around without souls already ~ maybe we might call them sociopaths.
Let's say we figure out what the "soul switch" is and then develop an injectible "fix" for that problem.
Would it be considered ethical or unethical to create souls in humans without souls?
(NOTE: this is like counting the number of angels dancing on the head of a pin of course, but this whole business can be flipped around and aimed right at the sociopaths who PREFER embryonic stem cells. It threatens them with their own science. Further, imagine the guilt pangs they feel after growing a soul. Another avenue of debate might be what the anti-vaccination people would do?)
I’ve been trying to get this point across the anti-embryonic stem cell contingent on FR a few years now. As soon as any stem cell from any source is perfected as a therapeutic tool, it will also be capable of being turned into a viable embryo. Cells are made of specific molecules in specific arrangements, and science is progressing very rapidly in its ability to rearrange the molecules in any way that’s wanted. A stem cell that can be coaxed to develop into a replacement heart OR kidney OR liver OR pancreas can also be coaxed to develop into ALL of those along with all the other parts of normal living body. In the end, it makes no difference whether the starting cell came from an embryo or from umbilical cord blood or from adult skin.
And people who subscribe to reality see that there’s no conflict between those two ideas.
BTW, if the objective is to get stem cells that can be used to repair/grow/replace specific organs, or organ systems, why would we wish to reset a cell all the way back to the embryonic level? Wouldn't we be happy to have the stemcells specific to the organ in question?
I’ll let God decide whether or not to give life to the creations of man.
Major organs aren’t made of just one kind of cell, and they require a fully stocked bloodstream to develop normally. You can’t just put a bunch of heart cells in a petri dish and get them to grow into a functioning heart. Location in relation to other cells of other types is critical to what cells develop into. It isn’t just being a “heart cell” that makes a cell divide and develop into a heart. And interestly, researchers recently took some non-heart cells, added some chemical goodies (probably derived from human blood/tissue) to the petri dish soup, and got the free floating cells to start contracting rhythmically like heart muscle cells. What may become possible in some cases is to transplant some partially differentiated cells into the patient’s body, adjacent to the organ that needs replacing, and have them take their cue from the environment and grow into a replacement organ in situ. That could theoretically work for some organs and under some conditions, but wouldn’t work when the organ that needs replacing is something like an endocrine or exocrine gland that is producing critically defective hormones or failing to produce needed hormones, since the environment would be inherently inhospitable to proper development. Obviously in situ growth wouldn’t work for organs that have been damaged by an infectious disease that is still present, such as tuberculosis or incurable strains of hepatitis, since the presence of the infectious organism would ensure that the replacement organ was thoroughly infected and damaged right from the start.
As for “why would we need embryonic stem cells in the first place”, you’re missing the point. No matter where they came from, they WOULD be embryonic stem cells, perfectly capable of developing into a new living organism, so there would no clear ethical difference in stopping the development of the embryonic cells that came from adult cells so they’d just become a certain organ or cell type, and doing the same thing with cells that came from an embryo.
The answer would be NO because the "determination" of whether that person had "full rights to exist" could be determined by being something "not quite equal to a human".
All animals are equal, some are more equal than others.
If one "race" of "subhumans" can be harvested for parts for the "full human" race, then it is genetic cannibalism.
All of this talk of "ethical" sources for embyonic stem cells for testing purposes dances around two issues:
(A) Why worry about it being "ethical" if the abortionists' line about it not being a human until it is delivered through the uterus (and even then it may not have the right to live) is "true".
(B) They make excuses that this is for "testing" purposes. If "success" is found with fetal stem cells, then they will need to harvest MANY more for practical application in the medical world.
Thanks for the ping.
Ping of interest.
Study: Painkillers Don't Help Elderly
Cornell researchers study bacterium big enough to see -- the Shaquille O'Neal of bacteria better pics
FReepmail me if you want on or off my health and science ping list.
Actually, people who subscribe to reality recognize that the ideas are opposite and antagonistic and the only difference is which philosophical worldview a person accepts as definitive.
To say there is no conflict is just Hegelian synthesis.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.