Activated eggs offer route to stem cells

A technique that could sidestep many of the limitations and ethical concerns that plague the production of human embryonic stem cells was unveiled late last month by a team of US and Russian researchers. The group managed to derive embryonic stem cells from an unfertilized egg - avoiding the need to use viable embryos.

"This is one of the papers we've been waiting for," says George Daley, a stem-cell expert at the Children's Hospital in Boston, Massachusetts, who was not part of the collaboration. But he and others caution that more work needs to be done before the method can be tried in the clinic. And the technique's dependence on access to fresh, unfertilized eggs - a controversial resource - is also likely to limit its application.

The team, led by Elena Revazova and Jeffrey Janus of Lifeline Cell Technology, a biotechnology company in Walkersville, Maryland, created embryos by activating an unfertilized egg using chemicals rather than fertilizing it with sperm (E. S. Revazova et al. Cloning Stem Cells 9, doi:10.1089/clo.2007.0033; 2007). Some lizards, birds and insects can...