Jun 27, 2007
The journal Nature features two studies in which scientists extracted rodent embryonic stem cells which closely resembled their human counterparts.
Previously extracted animal stem cells behaved very differently.
Substituting rodent for human embryonic stem cells could speed up research, as they would be easier to obtain, and less controversial to use.
The "epiblast stem cells", as they have been named, were taken from the rat or mouse embryo at a slightly later stage of its development than previous rodent embryonic stem cells.
Professor Roger Pederson, who led a team of scientists at Cambridge University, said they constituted "the missing link between mouse and human embryonic stem cells".
"On a molecular level, epiblast stem cells are more similar to human embryonic stem cells than to mouse embryonic stem cells."
Independently, scientists at Oxford University, made the same findings, a coincidence which both teams said bolstered each other's research.
Many scientists believe stem cells from embryos - rather than adults - are the most useful as they have the potential to become virtually any type of cell in the human body.
This means they offer great potential for "regenerative medicine", in which doctors hope they might be able to replace tissue that is damaged by disease.
Parkinson's and Alzheimer's are among the neurological diseases which are thought most likely to benefit from stem cell therapies, but they are also said to offer hope for conditions as diverse as heart disease, arthritis, diabetes, and burns.
But there are both practical and ethical issues surrounding the use of human embryos for stem cell research.
Scientists currently have to rely on obtaining surplus embryos from IVF clinics for their work, while some of those with religious convictions are unhappy at experimenting on and then destroying human life - even if it does pave the way to potentially life-saving treatment.
Despite the high hopes, so far there have been no major breakthroughs which suggest treatments are imminent.
The two studies do not in themselves offer cures for anything, but independent experts say they could dramatically speed up research if the findings really do stand up.
"In the future it should be much more straightforward to translate results obtained in lab rodents using these epiblast cells into procedures for stem cell therapies in humans," said Professor Harry Moore of the Centre for Stem Cell Biology in Sheffield.
"We would certainly want to use these new epiblast lines to test out the potential of therapies we are developing with human embryonic stem cells."
Professor Pederson himself said he thought the first clinical applications of stem cells were about five years away.
"Those would be very early studies that involve a human individual. I think we can envisage larger scale clinical trials occurring within a decade, certainly."