Two studies released today take further steps toward creating human stem cells without harming embryos, but are not expected to change dramatically the policy disagreements over embryonic stem-cell research.
Both studies, conducted in mice models and published in the journal Nature, attempt to resolve the core objection to such research — that embryos are destroyed to obtain their stem cells.
Andrew La Barbera, scientific director of the American Society for Reproductive Medicine, said the studies are “very significant advances,” although scientists don’t know whether the procedures would work in humans.
The first study — conducted by a team led by Robert Lanza of Advanced Cell Technology — uses a procedure known as single cell embryo biopsy, used to look for genetic defects, in which a cell is removed from an eight-celled embryo and tested.
The team took a cell from a mouse embryo and used the cell to develop stem cells without destroying the embryo.
The second study used the cloning technique to produce an embryo that is incapable of implanting in a uterus and developing to term, but still produces stem cells. In the cloning process, the nucleus of a body cell is combined with an egg to produce a cloned embryo. In the study, the body cell was stripped of the gene needed to produce a placenta and implant the embryo in the uterus.
Daniel Perry, president of the Coalition for the Advancement of Medical Research — which is pushing President Bush to expand his 2001 policy limiting federal funds for embryonic stem-cell research — said the new studies “show that good science occurs when researchers continue to press the horizons of regenerative medicine.”
Conservative groups expressed cautious optimism, but reiterated some of their moral concerns.
“It’s encouraging that scientists are even thinking about the ethical problems of embryonic stem-cell research,” said David Prentice, senior fellow for life sciences at Family Research Council. “But I don’t think these two techniques solve the ethical problems.”
Mr. Prentice said it is still not clear whether the embryo in the Lanza study will suffer long-term damage from the procedure. And he said the second study is morally flawed because it is “specifically creating a defective embryo” for research.
The studies could give a boost to House and Senate legislation that would provide federal funding to study methods of producing embryonic stem cells without harming embryos. But neither side wanted the new studies to divert attention from policy priorities.
For Mr. Prentice and other conservatives, the priority is securing a Senate vote on a House-passed bill that expands funding and research on umbilical cord blood, which is being used to treat some ailments.
“We continue to ignore the ethical answer we already have,” he said.
For Mr. Perry, the priority is allowing federal funding for research that uses leftover embryos from in vitro fertilization clinics. “That’s a much bigger issue than these papers,” he said.