'Missing link' stem cells found

Two independent teams of researchers have discovered a new type of embryonic stem cell in rodents which, they say, is the missing link between mouse and human embryonic stem cells.

New findings suggest that mouse and human embryonic stem cells are very similar

The teams - one based at Cambridge University and one at Oxford University - hope the discovery, and its virtually simultaneous verification, will change the way we think about human embryonic stem (ES) cells. The epiblast stem cells, as they have been termed, could accelerate understanding of stem cell development and help the derivation of stem cells in other species - including livestock and disease-prone mice used in research - thereby providing better models for researchers involved in stem cell research.
Professor Roger Pedersen whose laboratory led the Cambridge team said: “On a molecular level, epiblast stem cells are more similar to human embryonic stem cells than to mouse embryonic stem cells. The differences between mouse and human embryonic stem cells that we had attributed to species differences may actually come down to the developmental stages from which the cells emerge.”

The new mouse stem cells, which were taken from a later stage of development than the usual blastocyst stage, were maintained using the same growth factors as those used in the culture of human ES cells. The two British teams were able to produce stable cell lines which were used to work out how the novel cells remain pluripotent or begin to specialise during early development.

Because epiblast stem cells are so similar to human embryonic stem cells they will provide better models for human ES cells and will help move stem cell research toward potential therapies.

Sir Richard Gardner, who led the Oxford team said: “These findings suggest that human embryonic stem cells originate at a later stage of development than previously thought. Having both studies reach the same conclusions at the same time allows other researchers to use this new information immediately in their research. The fact that both studies made this discovery almost simultaneously is a clear sign of the momentum picking up in stem cell research. We are reaching a critical mass of understanding about these cells which should enable us to make the most of them in coming years.”