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US scientists report creating ‘ethical’ human embryonic stem cells in the laboratory, a technique that could bypass the need for embryos to be destroyed.
David Macauley, CEO of the UK Stem Cell Foundation, said:
“This is a remarkable achievement which addresses one of the major constraints to advancing research – the provision of reliable sources of clinical grade embryonic stem cells. ACT is a prime example of the vital role that the private sector can play in realising the commercial potential in stem cells for the benefit of all. It is inspiring to see scientific innovation being used to address the ethical questions often associated with stem cell research.”
Prof Robin Lovell-Badge, Head of Developmental Genetics, MRC National Institute for Medical Research, said:
“While perhaps a clever trick, I do not feel that this is much of an advance. The success rates were low as only 2% of cells isolated from the embryos gave rise to embryonic stem (ES) cell lines – in other words, at this rate it would only work for 1 in 50 embryos. And while the technique may provide an added bonus for couples undergoing PGD, to have an embryonic stem cell line matched to a child born after the procedures for future therapeutic use, it is very unlikely to be taken up by any one else. I am also unconvinced by the ethical arguments. Spare IVF embryos used to derive ES cell lines would have been destroyed anyway.”
Professor Peter Braude, Professor of Obstetrics and Gynaecology, Kings College London and St Thomas’ Hospital, said:
“Whilst this is a huge technical achievement and informs us about the plasticity of individual cells of the human embryo at the 8 to 16 cell stage, I am more sceptical about its clinical usefulness. We don’t undertake embryo biopsy willy-nilly, as it is better not to remove a cell from a developing embryo unless one really has to. We do it for preimplantation genetic diagnosis (PGD) for good medical reasons and for carefully calculated risk benefits. The cell is destroyed in the testing, so either two cells have to removed, or the single cell cultured overnight so that it divides, potentially delaying diagnosis, and presumably also jeaopardising stem cell development. I certainly cannot see why one would wish to try and remove a cell from a healthy embryo with such a low odds of developing a stem cell line from it when many thousands of useful cells can be harvested from the baby’s placenta at birth, if one needed to do it. Equally I am not persuaded by arguments that this is a more ethical way of getting stem cell lines, as it is not impossible that biopsy compromises the developing embryo from which one removes the cell.
“What is exciting is that there were embryos where only a few cells survived intact (grade III and IV)– not good enough to implant after IVF or to freeze – where stem cell lines could still be created from these ‘non-viable’ embryos. This may be acceptable to those who have ethical reservations about use of whole embryos, whatever their source, in stem cell generation procedures.”
Dr Stephen Minger, Stem Cell Biologist, Kings College London, said:
“This is a very interesting set of results from a scientific standpoint, and suggests that we may be able to increase the efficiency of human embryonic stem cell derivation from PGD embryos by culturing 6 or 8 individual blastomeres (or cells) from each cleavage-stage embryo rather than a single inner cell mass from the developmentally older blastocyst. But this work will be seized on by groups who will view this as a means of potentially generating stem cell lines by removing a single cell from normal embryos for stem cell derivation without destroying the embryo proper, despite the fact that thousands of IVF embryos are normally discarded every year. So from a practical perspective, this work has little direct relevance to stem cell derivation, but will add further fuel to the biopolitical debate about embryo research and stem cell derivation.”
Professor John M. Harris, Professor of Bioethics, University of Manchester, said:
“The science is wonderfully interesting and important and will convince those who already accept Pre-Implantation Genetic Diagnosis that the use of these cells is ethical. However hard line objectors to embryo research and use will probably still argue that if the removed cell might be toti-potent or if it could be returned to toti-potency, as seems possible, then it is effectively an embryo which will be wrongfully destroyed to make cell lines. The use of embryonic cells will only become non-controversial when it is accepted that the early embryo is of little or no moral significance.”
Professor Chris Shaw, Neurologist, Institute of Psychiatry, King’s College London, said:
“This is a useful alternative source for embryonic stem cells but it side-steps the crucial ethical question “What happens to those embryo’s found to have a genetic mutation and those that are healthy but excess to requirement?” If they are not going to be implanted they must eventually be destroyed. Isn’t it better that the donors are given the option of donating the unwanted blastocysts to advance medical research, rather than being frozen indefinitely?”
Professor Ian Wilmut, Head of the Department of Gene Expression and Development at the Roslin Institute, said:
“It would be very unfortunate if this result was used to discourage embryo donation because the authors make unjustified claims for their techniques. Cell lines have been obtained, but it is rather mis-leading to suggest that efficiency was equivalent to that with entire embryos. The authors themselves point out that further studies are required to confirm the potential of the cell lines.
“The authors imply that stem cell line derivation from one cell was as efficient as it would have been had the entire embryo been cultured. It is not clear if that was the case. The establishment of two lines from the equivalent of 35 high quality fresh embryos would be a disappointingly low efficiency.
“In making their comparison with other work it is important to realise that the authors selected good quality embryos whereas most other labs used all of the embryos that were available to them. After selection of high quality embryos for transfer to the woman, there would inevitably be fewer embryos of this standard, but all of the poorer quality embryos would be included.
“Finally, it seems that all of the cells of the embryo were cultured within the same drop for an initial period and in these circumstances cells may be dependent upon one another. Cells simply do not like being left alone.”