September 24, 2006
Human Embryonic Stem Cells Extracted From Dead Embryos

In a move that might provide a away around ethical objections to other ways to create human embryonic stem cells scientists were able to extract human embryonic stem cells from embryos that had ceased to grow

The journal STEM CELLS(R) today announced that scientists were able, for the first time, to derive pluripotent human embryonic stem cells (hESCs) from non-viable early human embryos.

The team, led by Professor Miodrag Stojkovic, derived hESCs using surplus and donated embryos that had stopped their cleavage. The scientists demonstrated that these non-viable embryos could be used under suitable laboratory conditions for derivation of hESCs and for study of early human development.

This progress, published in STEM CELLS(R), encourages other scientists to perform hESC research using both viable and non-viable pre-implantation embryos in their attempt to understand and fight debilitating diseases.

The professor who did these experiments is hopeful this approach will get around ethical objections to the destruction of embryos to extract stem cells.

'This should get round opposition to stem cell science because live embryos will no longer need to be used in all experiments,' said Professor Miodrag Stojkovic, the researcher who carried out the experiments at the Centre for Stem Cell Biology at Newcastle University last year.

The embryos used were from attempts at in vitro fertilization where the embryos stopped growing even before implantation.

Stojkovic's experiments were carried out while he was working at the Centre for Stem Cell Biology at Newcastle last year. In a paper, published last week online on the website of the journal Stem Cells, Stojkovic reveals he and his colleagues took 13 embryos, created by IVF. All 13 had stopped developing a few days after conception. 'They were in a very early stage of development,' said Stojkovic, now head of Sintocell, the Serbian medical research centre.

The team then waited 24 hours to check that the embryos were no longer dividing before beginning their experiments.

Some ethicists still see problems with this approach.

But other stem cell scientists and ethicists quickly raised a host of reasons that the advance may have little practical impact on the stormy research field. Among them are concerns that cells from dead embryos may be genetically abnormal, and the lack of a definitive test for proving that an embryo has no lingering potential for life.

How to get around the genetic abormality problem? In theory doctors could take embryos from pregnant women who die from trauma such as from car accidents. The removal of cells from embryos to use for therapy development would be analogous to using organs. But I'm guessing that the early stage pregnancies where the embryos still have pluripotent (highly flexible) stem cells aren't going to be recognized either by the mother or by emergency room workers.

It could turn out that some of the IVF embryos stop dividing for epigenetic (chemical state around the genes rather than the genes themselves) reasons. If that turns out to be the case then some stem cells extracted using this technique might turn out to be in good genetic shape.

The full paper is available with free access.Here's the abstract excerpted from the paper (PDF format).

Human embryonic stem cells (hESC) hold huge promise in modern regenerative medicine, drug discovery, and as a model for studying early human development. However, usage of embryos and derivation of hESC for research and potential medical application has resulted in polarised ethical debates since the process involves destruction of viable developing human embryos. Here we describe that not only developing embryos (morulae and blastocysts) of both good and poor quality but also arrested embryos could be used for the derivation of hESC. Analysis of arrested embryos demonstrated that these embryos express pluripotency marker genes such OCT4, NANOG and REX1. Derived hESC lines also expressed specific pluripotency markers (TRA-1-60, TRA-1-81, SSEA4, alkaline phosphatase, OCT4, NANOG, TERT and REX1) and differentiated under in vitro and in vivo conditions into derivates of all three germ layers. All the new lines including line derived from late arrested embryo have normal karyotype. These results demonstrate that arrested embryos are additional valuable resources to surplus and donated developing embryos and should be used to study early human development or derive pluripotent hESC.

Share |      Randall Parker, 2006 September 24 07:58 PM  Biotech Stem Cells


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