Free sample! |
CAIRNS: Researchers who were lauded last year for making stem cells without destroying human embryos, then accused of hyping data, now say they've done it for real. Thousands of people die each year waiting for organ transplants. One day human embryonic stem cells could fill the shortfall. The drawback is that to get human embryonic stem cells – with an accompanying quagmire of ethical issues – human embryos must currently be destroyed. Right? Maybe no longer. At an international meeting on stem cell research held in Cairns, Australia, Robert Lanza of Advanced Cell Technology in Worcester, Massachusetts, announced he had "produced the first human embryonic stem cells in existence to be made without destroying an embryo." "Till now the most vexing issue for embryo research has been the moral status of the embryo. These findings allow us to move on to issues of social justice; such as – who will get the treatments?" commented Laurie Zoloth an ethicist at Northwestern University in Chicago. Fall from grace In August 2006 Lanza showed the proof-of-principle in the British journal Nature (see, New stem cell technique eliminates ethical issues, Cosmos Online). The technique takes advantage of embryo biopsy - a standard procedure in IVF clinics. One cell from an eight-cell embryo is prised away to be tested for genetic diseases like cystic fibrosis. The remaining embryo carries on developing, unharmed. If the test shows the embryo to be healthy, it is implanted in a uterus. Thousands of babies have been born this way. What Lanza's group announced last year was that they could take the single cell or blastomere, and coax it to become an endlessly proliferating stem cell. Although these cells can't form embryos, they can form major types of human tissue just as bone fide embryonic stem cells do. So, cells could be removed from human embryos to make embryonic stem cell lines without destroying the embryo. When the Nature paper came out, Lanza was lauded: in one stroke he appeared to have cut an ethical Gordian knot strangling stem cell research. But the fall from glory was swift: a closer reading of the paper showed that in fact human embryos had been destroyed to produce the embryonic stem cells Indeed, the Nature paper had never claimed anything to the contrary. "We were demonstrating a proof of principle that blastomeres could be used to make embryonic stem cells, " Lanza told Cosmos Online. The reason for destroying the embryos at the time, was so that multiple biopsies could be done from a single embryo, meaning that fewer embryos overall were used to test the technique. Lanza never claimed that human embryos were not destroyed in his research. The reason for the confusion was a misleading press release issued by Nature that Lanza hadn't seen beforehand. It implied that no embryos had been destroyed in the generation of the embryonic stem cells. That misunderstanding saw Lanza come under heavy fire from everyone from church leaders to politicians. He ended up having to explain his research to irate U.S. lawmakers. "It was mind-boggling that it became such an issue," said Lanza. Redeemed promise But on Tuesday, Lanza redeemed the promise of his previous work by announcing a solution to the ethical problems at the 5th International Society for Stem Cell Research meeting. He told the audience his team had made embryonic stem cells from three human embryos that were now safely frozen away. These embryos should be viable since they were treated just the same as other biopsied embryos that go on to produce babies. In the latest technique, he described how a single cell (a blastomere) was removed from the eight-cell embryo, and then both the donor embryo and cell were grown side-by-side in the culture dish. This is necessary because the donor embryo sends signals that coax the cell to develop and multiply. After five days, the clump of blastomere cells is weaned off the mother embryo, and transferred to another dish where it is now nurtured by established human embryonic stem cells. Finally, the blastomeres join their ranks, and become human embryonic stem cells themselves. Meanwhile the original donor embryo is safely returned to the freezer. Lanza is now waiting on the findings of a legal review within the U.S. National Institutes of Health to determine whether the technique for making the new cell lines would sidestep an existing U.S. federal research ban. Scientists need to make more human embryonic stem cell lines to advance their research, but they are banned from using U.S. federal funds because current techniques to make them destroy human embryos – something that U.S. President George W. Bush strongly oppose: Bush has twice vetoed the U.S. Congress from allowing funding to create new human embryonic stem cell lines. 
|
COSMOS newsletter!Receive regular updates highlighting the latest in science from COSMOS. |
||
