WHEN is an embryo dead? Is it: a) when it stops growing but still contains cells that could possibly be revived; or b) when it has absolutely no signs of life?
The answer is important because it could decide whether a new source of human embryonic stem cells (hESCs) is deemed ethically acceptable. Although these cells have huge potential, with their ability to turn into any cell type in the body, some people oppose their use because until now, their only source has been human embryos.
鈥淭he question could decide whether human embryonic stem cells can be used鈥�
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Now, Miodrag Stojkovic at the Prince Felipe Research Centre in Valencia, Spain, and his colleagues say they have successfully extracted hESCs from embryos he classes as lifeless. They obtained a single line of hESCs from 13 鈥渁rrested鈥� embryos, which 鈥渄o not resume cell division and cannot be said to be live鈥�, writes Stojkovic in Stem Cells (DOI: 10.1634/stemcells.2006-0377).
But not everyone thinks the embryos were actually dead. 鈥淭hey are arrested, but still metabolically active,鈥� says Stephen Minger of King鈥檚 College London. 鈥淪o technically they鈥檙e still alive, and to spin it bio-politically as an ethical source of hESCs is completely misleading,鈥� he says.
Stojkovic claims that his aim was not to solve the ethical dilemma, but to make the best use of all possible sources of hESCs, even those given up for dead.
