From theglobeandmail.com

TORONTO — A team of Canadian scientists has made a discovery about how human embryonic stem cells develop that could change the direction of research into what has been dubbed the Holy Grail of regenerative medicine.

Embryonic stem (ES) cells give rise to every tissue in the body — from the liver and heart to the bones and brain. Scientists around the world are working to understand how they might be harnessed to cure a wide variety of diseases, from growing a whole new organ to replacing brain cells damaged by Parkinson's or Alzheimer's.

In a paper published online Wednesday in the journal Nature, researchers at McMaster University say they have discovered that stem cells have a far more complex relationship with the cells around them — and that knowledge could open up entirely new avenues of research.

Previous studies in mice have shown that various types of stem cells hole up in little nests of cells known as niches, and these niches are located in specific spots within various tissues, said principal investigator Mick Bhatia, scientific director of the McMaster Stem Cell and Cancer Research Institute.

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