CAIRNS, AUSTRALIA--Confirming earlier predictions, stem cell expert Robert Lanza of Advanced Cell Technology in Worcester, Massachusetts, announced today that his team has succeeded in producing human embryonic stem (ES) cells without destroying embryos. Lanza is currently in discussions with the National Institutes of Health (NIH) to determine whether the new technique--reported here at the 5th International Society for Stem Cell Research--sidesteps U.S. restrictions on federal funding for ES cell research.
Lanza first broached the possibility last August, when his team showed that a single cell, known as a blastomere, from an eight-cell human embryo could be used to generate a line of bona fide ES cells. The same technique, known as preimplantation genetic diagnosis, is used to biopsy laboratory-made embryos for genetic abnormalities. After the single blastomere is removed, the seven-cell embryo goes on to develop normally.
So in theory, blastomeres could be removed from human embryos to make ES cell lines without destroying the embryo. But when Lanza's team first did the work, they had to destroy embryos, in part to enable multiple biopsies from a single embryo. A press release accompanying the paper, which appeared in Nature, implied that no embryos had been destroyed in the generation of the ES cells. That misunderstanding put Lanza into the middle of a firestorm that saw him having to explain his research to the U.S. Congress.
Now, Lanza reports that his team has reproduced the work--this time without destroying embryos. After removing the blastomere, the researchers suspended it in a microdrop of culture medium with the donor embryo close by. Signals from the donor embryo coaxed the blastomere to keep proliferating. Eventually, the blastomeres were removed to a group of mouse support cells that helped maintain the human cells as ES cells. Meanwhile, the original blastocyst embryo was safely returned to the freezer. "These are the first human embryonic stem cells in existence to be made without destroying an embryo," said Lanza, whose team is preparing the findings for publication.
Lanza is now waiting on the findings of a legal review within NIH to determine whether the technique will get around the current federal funding ban on stem cell research (ScienceNOW, 7 June). Lanza has also submitted a grant proposal to test his cell lines alongside two other types of stem cells that are also considered "ethically acceptable." Among other things, the work would compare the ability of the cells to give rise to different tissues or tumors.
"It's fascinating to see the explosion of these alternative pathways to making stem cells," says Laurie Zoloth, an ethicist at Northwestern University's Feinberg School of Medicine in Chicago, Illinois. "These findings allow us to move on from vexing issues like the moral status of the embryo and egg extraction to issues [such as] ... who will get the treatments."