Scientists have created embryonic stem cells using dead embryos, it was revealed today. By avoiding the need to deliberately destroy an embryo, the technique could offer a way of producing embryonic stem cell lines that would be ethically acceptable to pro-life groups.
Embryonic stem cells are capable of turning into any cell or tissue type in the body, and scientists think they offer great potential to treat diseases such as Alzheimer's. But to create a stem cell line scientists have had to destroy an embryo - typically one that is surplus to requirements during IVF treatment.
Now Miodrag Stojkovic at Sintocell in Leskovac, Serbia and his team has shown that it is possible to establish stem cell lines from embryos that have stopped dividing. Some embryos are not implanted during IVF treatment because they have visible defects. The new findings suggest that these could be used to make stem cells lines.
"My purpose was to demonstrate in a scientific manner that these arrested embryos - dead embryos - could be used for scientific purposes," said Dr Stojkovic, who was part of the British team that cloned the first human embryo in 2005. He said he supports the use of living embryos to harvest stem cells, but added that using dead embryos might allow scientists to circumvent restrictions, in countries such as the United States, on using live embryos to create stem cells.
The study, which is published in the journal Stem Cell, used very early embryos that are bundles of between 4 and 24 cells. Out of 13 embryos that stopped dividing at 6 to 7 days old, cells extracted from 5 of these went on to develop structures typical of stem cells. The scientists were able to establish a stem cell line from one of these. By comparison, using living 4-day-old embryos, the team was able to establish 2 new stem cell lines.
However, Helen Watt, director of the catholic Linacre Centre for Healthcare Ethics said ethical concerns remained. "If the aim in waiting for natural death - or what we guess is natural death - is to satisfy legal or political concerns, the death of these embryos may even be intended, not merely foreseen," she said.
Dr Watt added that the Catholic church had "serious moral concerns" about IVF anyway. "Use of IVF embryos - even dead embryos - would normally involve close complicity with IVF practitioners, of a kind which could not be justified."
Robin Lovell-Badge, a leading stem cell scientist at the National Institute for Medical Research in London, said the researchers could not be sure that an embryo was truly dead.
"They have no proof that this embryo, if it had been transferred back into a womb perhaps a day or two days earlier, would not have produced a baby," he said, "You can never answer that question."
The problem, he said, is that conditions in the lab can never be as favorable as they would be in the womb, so an embryo that could have survived there might appear inviable in the petri dish. "The culture conditions are never perfect, and just by slightly mishandling an embryo you can compromise its ability to develop."
But Robert Lanza, a stem cell expert at Advanced Cell Technology in Worcester, Massachusetts, welcomed the study. "We need to pursue all the options open to us," he said. "The question is whether we will be able to convince the politicians that it makes any difference."
In a separate study published in Cloning and Stem Cells, Dr Lanza's team showed that it is possible to repair eye disease in rats using human embryonic stem cells. The rats he used had damage similar to age-related macular degeneration, a disease that afflicts 30 million people worldwide, typically those over 60. The study involved injecting stem cells into the space below the retina.