Stem cells from `dead' embryo
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Criteria for embryo's death not clearly defined
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SCIENTISTS SAY they have created a stem cell line from a human embryo that had stopped developing naturally, and so was considered dead. Using such embryos might ease ethical concerns about creating such cells, they suggested.
One expert said the technique makes harvesting stem cells no more ethically troublesome than organ donation. But others said it still carries scientific and ethical problems.
Human stem cells
Scientists want to use human embryonic stem cells to study diseases and create transplant tissue for treating illnesses such as diabetes and Parkinson's disease.
Such cells are taken from human embryos that are a few days old, and the harvesting process destroys the embryo. That raises ethical objections. The new work, published online by the journal Stem Cells, comes from Miodrag Stojkovic of the Prince Felipe Research Center in Valencia, Spain, with colleagues there and in England.
They studied embryos donated by an in vitro fertilisation clinic with the patients' consent.
Part of the work focused on 132 `arrested' embryos, those that had stopped dividing for 24 or 48 hours after reaching various stages of development.
Thirteen of these embryos had developed more than the others, reaching 16 to 24 cells before cell division stopped. Scientists were able to create a stem cell line from just one of these embryos.
These stem cells performed normally on a series of tests, Stojkovic said in a telephone interview. He said he did not know whether the result indicated a solution to ethical concerns about embryonic stem cells. The point of the research was to show that such embryos provide an additional source of the cells beyond healthy embryos, rather than to set up any kind of a competition, he said.
Ethical dilemma
Both sources should be used, he said. But others said the approach fails to solve the ethical problems.
Dr. Donald W. Landry, director of the division of experimental therapeutics at the Columbia University Medical Center in New York, says an embryo is dead if its cells irreversibly stop working together to function as a single organism.
But even under that definition, Pacholczyk said, scientists know too little about early embryos to discern when one is truly dead. — AP
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