Researchers Report Growing Stem Cells From Dead Embryos
Saturday, September 23, 2006
Researchers reported Thursday that they had cultivated a colony of human embryonic stem cells from an apparently dead embryo, a strategy some have suggested might be less controversial than conventional approaches that require the destruction of living embryos.
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 do you know when an embryo is dead?" asked Eric M. Meslin, director of the Indiana University Center for Bioethics.
The work, reported in the online journal Stem Cells, was led by Miodrag Stojkovic of Sintocell in Serbia and the Centre for Stem Cell Biology and Developmental Genetics at England's University of Newcastle upon Tyne.
The team started with 13 embryos that had been created in a fertility clinic by in vitro fertilization (IVF) and had stopped developing after a few days. When those "arrested" embryos showed no progress after 24 hours, the team deemed them "generally regarded as dead," dissected them and cultivated their cells.
The hope was that a few cells might still have the potential to grow, even if the embryo as a whole did not -- just as viable organs can be retrieved from dead people. And it worked: From those cells, one healthy colony of stem cells grew.
"Usage of arrested embryos offers an attractive option," especially in countries where research on live embryos is restricted, the team concluded.
Many IVF embryos fail to develop, suggesting that the approach might boost the supply of stem cells for study, some experts said. But many of those embryos have abnormalities -- the very reason they stopped developing -- and so would be of questionable value in research, several said.
"Anything that makes it possible for science to advance in this area is to be applauded," said R. Alta Charo, a bioethicist and law professor at the University of Wisconsin at Madison. "But this should not be used as an excuse not to finance the most promising forms of research we already know about," she said, referring to work done on healthy embryos already slated for destruction at fertility clinics.
President Bush recently vetoed legislation that would have allowed federal funding of such studies.
Even if everyone could agree that arrested embryos are dead, it is not clear how the approach could satisfy those who believe that embryos have the same moral standing as born people. Researchers certainly cannot expropriate body parts from people after they die without advance consent, some noted.
"You can't wait for a person to die and say, 'Now I'm going to do to them what I couldn't do when they were alive,' " Meslin said.
At the same time, he said, scientists are unenthusiastic about using cells from faulty embryos.
"Both sides might agree here that this is a route that's not going to be very productive," Meslin said.
The new research was immediately rejected by British representatives of the Catholic Church, who decried the work because it depends on the use of embryos made by in vitro fertilization. The church opposes IVF because it separates sex from reproduction.