New stem cell techniques avoid ethical concerns
The journal Nature published papers on both techniques in its online edition on Sunday. They work well in mice and the researchers believe they could be applied to human stem cells.
The more positive technique comes from Advanced Cell Technology (ACT), a Massachusetts biotechnology company, working with scientists at the University of Wisconsin. In a procedure similar to that used in pre-implantation diagnosis to test human IVF embryos for genetic defects, they removed a single cell from a newly fertilised mouse embryo and grew embryonic stem cells from it.
The ACT group is the first to publish the successful derivation of stem cells from a mammalian embryo without killing it. The mouse embryos developed normally after stem cells were derived from them.
Robert Lanza, head of the ACT team, said that, if applied to humans, the technique would overcome “the most basic objection to embryonic stem cell research: the fact that embryos are deprived of any further potential to develop into a complete human being”.
The technology may eventually make it possible to generate and bank human embryonic stem cells, which would be genetically identical to children born from the transferred IVF embryos. These stem cells could be used decades later for regenerative medicine.
The second technique, from Rudolf Jaenisch and Alexander Meissner at the Whitehead Institute for Biomedical Research in Massachusetts, is an attempt to get round some ethical and religious objections to therapeutic cloning. It is a practical demonstration of an idea first proposed by William Hurlbut of Stanford University, a member of the President's Council on Bioethics.
The theory is that scientists extract stem cells from embryos that are genetically altered to make it impossible to implant in the uterus. Because they cannot develop they are not potential human lives. The Whitehead scientists achieved this in mice by disabling a gene that is essential for implantation.
Commenting on the Nature papers, Irving Weissman, a leading stem cell scientist at Stanford University, said: “Although the efforts cited here will be criticised as a diversion of good science by politics, I believe all of these attempts to advance and translate medical science should be pursued in parallel.”