"Missing link" stem cells may speed race for cures

By Ben Hirschler

LONDON (Reuters) - Scientists have discovered a new type of embryonic stem cell in mice and rats that should speed up research into regenerative medicine and help in the hunt for cures to a range of diseases.

Two independent teams from Britain's Oxford and Cambridge universities said on Wednesday that so-called rodent epiblast stem cells were very similar to human embryonic stem cells, making them particularly good models for analyzing human health.

The new cells effectively constitute a "missing link" between mouse and human embryonic stem cells, according to Roger Pedersen, leader of the Cambridge group.

Human embryonic stem cells are the source of every cell, tissue and organ in the body. Scientists want to use them to find cures for diseases like Parkinson's, cancer and diabetes, although critics say it is wrong to use any embryo in this way.

Laboratory mice have long been a favourite model for human disease but researchers have been frustrated by the fact that human and mouse stem cells behave very differently.

Now scientists think they may have cracked the problem.

INSIGHT

Two papers published in the journal Nature show that when mouse stem cells are derived from the innermost cell layer -- or epiblast -- of a week-old rodent embryo they are in many ways almost identical to human ones.