WASHINGTON Researchers at a U.S. company trying to push the margins of stem cell research said on Friday they had grown human embryonic stem cells using a non-controversial method that did not harm the embryos.
They said they had grown several lines, or batches, of the cells using a single cell taken from an embryo, which they then froze unharmed.
"We generated three new lines," Dr. Robert Lanza of Advanced Cell Technology Inc. told Reuters.
"These are first human embryonic cell lines in existence that didn't result from the destruction of an embryo."
Lanza gave a brief summary of the work to a meeting of the International Society for Stem Cell Research in Cairns, Australia this week. He plans to publish details in a medical journal.
ACT hopes the approach might bypass objections to human embryonic stem cell research. U.S. President George W. Bush vetoed a bill this week that would have broadened federal funding of such work.
Researchers say these cells, taken from days-old embryos, might provide a way to regenerate all sorts of tissues, blood and perhaps even organs. And studying them might help them learn how to reprogram ordinary cells.
Some countries, such as Britain, encourage this work. But opponents such as Bush say it is immoral to destroy a human embryo.
Last year, Lanza's team reported they had derived stem cells from a human embryo by taking just one cell at a time.
In theory, this would be the same as is done already in some fertility clinics when parents get embryos tested for genetic defects so they can conceive children free of diseases such as cystic fibrosis.
This method, called pre-implantation genetic diagnosis or PGD, has been shown to be safe, with healthy babies born after it is performed.
But Lanza said he did not want to waste any embryos, so he in fact used more than one cell from the embryo for his experiment last year, destroying the embryo. Critics of human embryo research denounced his work.
This time, his team used just a single cell from each of three embryos and then froze the embryos. "These embryos remain frozen. They are still alive," Lanza said.
One contains a genetic defect that will doom it, called trisomy 16. "Those embryos can never go past the first trimester. Even if the embryo were implanted it could not give rise to a viable child," Lanza added.
"If that is not going to satisfy them, I don't know what is going to."
"Despite the veto, and particularly in light of this new advance, we call on the National Institutes of Health to reflect the will of the American people and approve funding for research applications of our single cell blastomere technology," William Caldwell Chairman and Chief Executive Officer of ACT, said in a statement.
Now Lanza hopes to team up with other researchers who have found alternative sources of embryonic-like stem cells to compare the methods.
They include former colleague Dr. Anthony Atala, now of Wake Forest University in North Carolina, who has discovered embryonic-like stem cells in the amniotic fluid that surrounds fetuses in the womb.
And he says his team has also found a way to produce red blood cells from human embryonic stem cells, perhaps offering a way to some day produce large quantities of human blood for transfusions and other uses. That work also has yet to be published.