Read an Buzz blog post on pre-implantation genetic diagnosis, which relies on the same method of removing a single cell from a developing embryo. (This is the screening technique that Laurie is referring to above.) You can also check out a poll on the technique from a few months ago. (Be sure to read the comments, as they're far more interesting than the straight data.)

According to an article in the New York Times ("Stem cell news could intensify political debate," Nicholas Wade; August 24, 2006),

"Although [Dr. Robert Lanza, vice president of Advanced Cell Technology and leader of the research team] used discarded human embryos, he said that anyone who wished to derive human embryonic stem cells without destroying an embryo could use a blastomere removed for [preimplantation genetic diagnosis].

'By growing the biopsied cell overnight,' he said, 'the resulting cells could be used for both PGD and the generation of stem cells without affecting the subsequent chances of having a child.'"

Right now, government funding for embryonic stem cell research is mostly prohibited by the Dickey-Wicker amendment, which says a human embryo cannot be harmed or exposed to undue risk.

So now the debate on federal funding will likely shift to the definition of "undue risk." Obviously, removing a blastomere involves some risk, yet embryos that have undergone PGD seem as healthy as other babies conceived by in vitro fertilization. (In the last decade, more than 2000 babies have been born in the US after PGD.)

Some groups applaud this new development as a way of ending the impasse about the permissibility of embryonic stem cell research.

Others still have ethical qualms.

• The United States Conference of Catholic Bishops opposes both in vitro fertilization and preimplantation genetic diagnosis, as well as any form of embryonic stem cell research, because "of the high death rate of embryos in clinics and because divorcing procreation from the act of love [makes] the embryo seem more a product of manufacture than a gift."
• Dr. Leon Kass, former chairman of the President's Council on Bioethics, said that the long-term risk of preimplantation genetic diagnosis is unknown and that the present [stem cell harvest technique] is inefficient, requiring many embryos to produce a single stem cell line.
• And Dr. Irving Weissman, a stem cell expert at Stanford University, said that the new method, using only blastomeres from PGD, would not provide researchers with cells derived from patients with a specific disease. (Many scientists feel that embryonic stem cells will allow them to explore the basic mechanisms of disease, but they need access to cells with those genes.)

Whoa! Italian-French researchers, published in Nature, say that they transplanted stem cells into dogs with Duchenne muscular distrophy, and the dogs' symptoms greatly improved.

Muscular dystrophy is a group of genetic disorders that causes muscles to weaken over time. It also limits mobility, and shortens life span, and right now there is no cure. Duchenne muscular dystrophy affects one in 3,500 boys, and is caused by a lack of dystrophin, a protein that helps maintain muscles.

The researchers used stem cells from healthy dogs and also from dogs with muscular dystrophy (MD). (They modified the MD dogs' stem cells to "correct" the bad gene.) They injected the stem cells into dogs with MD.

According to this article,

"Four out of the six dogs who received...stem cells [from healthy dogs] saw the return of dystrophin and regained muscle strength. One dog that was injected at an early-stage of the disease retained the ability to walk, and two dogs injected at a late-stage of the disease had their mobility returned. Of the remaining two, one died early and the other, the scientists believe, did not receive enough cells.'

MD dogs injected with their own "corrected" stem cells showed much less improvement, although the dystrophin protein returned. (That's a bummer, because the researchers had hoped that, when and if the treatment is ever used on humans, patients could be injected with their own cells, sparing them from the risk of rejection and a lifetime need for immunosuppressant drugs.)

It's promising, but even if this research is repeated and improved upon, use of stem cells to treat Duchenne muscular dystrophy in humans is still years away.