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> Comment
on the "Official Website of Altered Nuclear
Transfer(ANT)" (new) > On the moral status of cells generated through Altered Nuclear Transfer > On the moral status of cells generated without genetic material from a male sperm cell (parthenotes) > On the moral status of cells generated through Oocyte Assisted Reprogramming (OAR) Comment on the "Official Website of Altered Nuclear Transfer(ANT)" (www.alterednucleartransfer.com) April 10, 2006
We are convinced that the issue of
distinguishing between a sick-embryo
and a pseudo-embryo is a key one to break through in the fight for the
rights of the embryo. ANT and OAR have the great merit of bringing this
issue into focus. But it is crucial to establish a criterion allowing
us to solve the issue. We propose the Direct Inhibition of the
Appearance of Neural Activity (DIANA). The Editors of Embryoperson See the presentations
in www.embryoperson.org
:
On the moral status of cells generated through Altered Nuclear Transfer October 17, 2005 Alexander Meissner and Rudolf Jaenisch report first experimental results about the generation of pluripotent embryonic stem (ES) cells through Altered Nuclear Transfer (ANT) in mice (Nature, published online 16.10.2005, doi:10.1038/nature04257). This technique was proposed by the Stanford bioethicist William Hurlbut as a method of generating human ES cells without destroying human embryos. ANT creates abnormal nuclear transfer blastocysts that are inherently unable to implant into the uterus but would be capable of generating customized ES cells. Because of preimplantation lethality, the ANT-derived cells are supposed to be “pseudo-embryos” (non-embryonic biological entities), which do not deserve the moral status of true embryos. However we think that Hurlbut’s proposal should be questioned. Indeed a human egg undergoing an abnormal and lethal growth in a very early developmental stage can very well be a sick true embryo and not only a “pseudo-embryo”. Engineering deliberately a sick embryo unable to implant is morally the same as simply not implanting a normal embryo. In order to establish a scientific basis for distinguishing between a sick embryo and a “pseudo-embryo” we propose to consider the cells called parthenotes, which are generated by stimulating human eggs to start cleaving without the addition of any genetic material from a sperm or other separate source. These parthenotes can implant into the uterus wall, and develop till the stage when heart beating and blood circulation appears. Nevertheless, because of deficiencies in their epigenetic information, they cannot go beyond and unfold spontaneous fetal motility (Kono T. et al., 1996). Such parthenotes can be considered to share the same moral status as a brain dead adult. If one considers moral to obtain organs from a brain dead, nothing speaks against obtaining ES cells from such parthenotes. We call SIENA¹ (Specific Inhibition of the Emergence of Neural Activity) a genomic alteration that tolerates healthy development till reaching heart beating and blood circulation, but inhibits the emergence of the brain activity responsible for spontaneous fetal motility. SIENA¹ alterations (as for instance those that parthenotes exhibit) generate pseudo-embryos. Other alterations generate sick embryos. The fact that in a well functioning uterus an embryo unfolds
spontaneous movements and not only heart beating and blood circulation,
depends on the embryonic genetic and epigenetic information, and not on
any information coming from the maternal organism. In this sense
implantation is irrelevant for the moral status The Editors of Embryoperson ¹Instead of this concept we use meanwhile the concept DIANA. See the presentation "DIANA genomic alterations"
On the moral status of cells generated without genetic material from a male sperm cell (parthenotes). September 22, 2005 As BBC News 2005/09/09 reports, a team of the Roslin Institute (Edinburgh) has created six parthenotes stimulating human eggs to start dividing like an embryo without the addition of any genetic material from a male sperm cell. The Edinburgh-based team hopes to obtain embryonic stem (ES) cells from the parthenotes and use them to investigate their potential in laboratory research and in medical treatments. Parthenotes can implant into the uterus wall, and develop till the stage when heart beating and blood circulation appears. Nevertheless, because alterations in the genomic information (gene expression program), they cannot go beyond and unfold spontaneous fetal motility. Therefore, parthenotes cannot be considered as true human embryos but should rather be considered to share the same moral status as a brain dead adult (see presentation). If one considers moral to obtain organs from a brain dead, nothing speaks against obtaining ES cells from parthenotes. By contrast, destroying in vitro fertilization embryos to harvest ES cells is a violation of the human rights. Parthenotes are pseudo-embryos, i.e. non-embryonic entities exhibiting only an embryo-like development , and one should avoid to call them embryos. Also the term ‘virgin conception’ is confusing, for parthenotes should not be considered human persons. The Editors of Embryoperson On the moral status of cells generated through Oocyte Assisted Reprogramming (OAR) A number of advocates of embryo-free methods for generating pluripotent human have published a joint statement (Joint Statement 2005) supporting a proposal put forth by Markus Grompe: Oocyte Assisted Reprogramming (OAR) (Grompe and George 2005; Vogel 2005). In OAR one intends to fuse a somatic cell with an enucleated oocyte, but previously altering the input somatic cell or the oocyte so as to preclude formation of a human embryo. Grompe proposes to overexpress a gene like nanog before fusion, which might promote nuclear reprogramming of the donor somatic cell directly to an embryonic stem cell, and avoid generating any entity mimicking embryonic development. For OAR to be considered morally unobjectionable, it is important to show that the single cells resulting through OAR are pluripotent stem cells and not single-celled embryos. Even if backers of OAR hope that this is the case, they acknowledge that one cannot reach this conclusion before obtaining clear results with animals. Indeed, the fact that nanog is highly expressed in the ICM and in the ESCs but not in oocytes or single-celled embryos, does not necessarily mean that nanog overexpression in a oocyte leads to the complete failure of early embryonic development. The cells of the single-celled or two-celled stages and the ESCs derived from the ICM of a blastocyst have quite different gene expression patterns. For the time being, the only experiments with such stages did not involve ‘overexpression’ but ‘deletion’ of nanog, and show that this deletion does not prevent early cleavage stages of embryogenesis including formation of the ICM but does prevent the formation of an epiblast (Mitsui et al. 2003). This result stresses the importance of nanog expression for building the proper embryo. By contrast it is not yet known how behaves a fertilized egg resulting from an oocyte, which was injected with a nanog vector. A nanog-expressing fertilized egg will most likely be capable of undergoing early cleavage otherwise OAR would be useless. But it may be difficult to distinguish the resulting cells from true embryonic blastomeres. In this case one could not rule out that such cells form a true embryo affected by an injure leading to preimplantation lethality, which could be rescued through an appropriate therapy as for instance tetraploid complementation. Then, additionally to nanog overexpression, it would be necessary to introduce a SIENA¹ alteration (see presentation) for granting an ethically unobjectionable method, the same way as for ANT. Therefore, experiments with nanog-expressing fertilized eggs in mice and primates are crucial. Only such experiments can tell us whether a morally unobjectionable OAR will be in the end more practical than generating pluripotent stem cells from parthenotes. Notice also that up till now no ape is born through SCNT. This means that in primates reprogramming somatic cells is at least a highly defective technique. It is therefore important to exclude that OAR cells fail to develop because defective reprogramming rather than nanog expression. The Editors of Embryoperson ¹Instead of this concept we use meanwhile the
concept DIANA. See the presentation "DIANA genomic
alterations" References
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