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Stem Cells Without Embryo Destruction
Nature is reporting that biologists have revealed the details for two different techniques to derive stem cells without embryo destruction that have been purely theoretical until now. While both methods work in mice and could, in principle, be applied to human embryos, scientists, ethicists and politicians are split over two techniques’ merits.
One method, developed by Rudolf Jaenisch and Alexander Meissner of the Massachusetts Institute of Technology, is described as a variant of therapeutic cloning and is dubbed altered nuclear transfer (ANT). In this method a gene in the patient’s donated cell is switched off before the nucleus is transferred into a fertilized egg. The resulting egg grows into a normal ball of cells called a blastocyst from which ES cells can be derived, but the deactivated gene means that the ball lacks the ability to implant in a uterus and so develop into a baby.
The second method, developed by a team led by Robert Lanza of Advanced Cell Technology in Worcester, Massachusetts, involves plucking single cells called blastomeres from eight-cell embryos. The new ES lines are derived from the blastomere, while the embryos go on to form apparently healthy babies. This raises the possibility of deriving fresh stem-cell lines from human embryos being used for in vitro fertilization before they are transferred to the uterus.
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Having the cake and eating it too? by LordDilly
So I’m taking it that this means that if stem cells can be harvested without embryo distruction, that means that embryonic stem cell research could be conducted in a manner free from the ethical dilemma faced in the old method i.e. from aborted or viable fetus’ that would have otherwise been destroyed. (Mayhap I just put myself in the running for the Captain Obvious award) Of course there is still the ethical consideration of potential biotech that might be gleaned from any advance- cloning, ect. Will be interesting to follow.
Hazy Ethics by Valerie
The "ethics" in these two methods of obtaining ES cells are very complicated.
ANT allows for an otherwise normal embryo to result that is unable to implant, and thus grow into a baby. As Brad mentioned, the same would occur if you created embryos via IVF and simply did not place them back in the uterus. Intra-uterine devices, a method of birth control, also do the same thing, as they create an endometrial environment which is hostile to embryo implantation. Plan B, or the "morning after pill" has a similar effect. The Catholic Church and other churches consider IUDs and Plan B abortifacients. So preventing a normal embryo from implantation by any means (including genetic alteration), and thus calling it "non-viable" seems rather dishonest.
PGD is also ethically tricky. For one, the cell that is "biopsied" from a developing embryo could itself develop into an independent, fully formed baby. In essence, you could call that cell a zygote (the cell formed from the fusion of the original sperm and egg.) If you biopsied half of the blastocyst cells, you’d make a twin in the same way that nature does. If you just take one, you could have a similar result.
Two, PGD can injure the developing embryo. Working with a Reproductive Endocrinologist, we must counsel patients about that procedure that the embryos can die even if they are genetically normal. (Older mothers with higher chances of aneuploidy usually ask about PGD.) (The PGD link I provided is excellent if you want to read more about it.)
So the ethics of these new methods are anything but cut and dried. Ultimately the question eclipses the usual "at what point does life begin?" and goes on to "is potential life life?"
Perspective accounts for much by bradsmith
Many posts have been made centering around the purpose and viability of an embryo. While most would agree that much of the debate boils down to an unclear definition of the onset of life, I do think that perspective has something to do with it. As to the purpose of an embryonic cell, from a cell biologists perspective, it is merely to undergo it’s cell cycle. By this I mean, growth, nuclear replication, division, and so on. Which it an ANT modified culture does. A cell seeks only to complete this cycle, and not to meet any end result. That is the "life" of a cell. Or in this case…a clump of cells.
I post this in order to clarify some of the discussion I have had with Brandon over whether ANT truely represents an option of obtaining stem cells without the destruction of an embryo. I think you have classified an embryo as something greater than cells, or having a greater purpose. Perhaps it’s all of the biology classes that I have had brandon, that prohibt me to concede to the limited scope of viability that we have discussed.