The amazing stem cells.


Specialized Adult Stem Cells Re-Grow Fingertips
Last Updated: August 24, 2011.


Study finds they are not 'jack of all trades' cells, as previously thought.


WEDNESDAY, Aug. 24 (HealthDay News) -- Specialized adult stem cells are make it possible for mammals to re-grow the tips of injured fingers or toes, rather than a "jack of all trades" cell type formed in response to serious injury, a new study shows.

Researchers from Stanford University found the regenerating stem cells are tissue-specific, meaning each has a particular job regenerating bone, skin, tendon, vessels or nerves.

The findings call into question a popular theory that damaged extremities are regenerated by a bump of cells considered "pluripotent," meaning that they are able to grow into a variety of cell types. This versatile bump of repair cells is called a blastema, but it appears to have nothing to do with fingertip regeneration.

"We've shown conclusively that what was thought to be a blastema is instead simply resident stem cells that are already committed to become specific tissue types," said Dr. Irving Weissman, director of Stanford's Institute for Stem Cell Biology and Regenerative Medicine in a news release. "The controversy about limb regeneration in mammals should be over."

Mice and some humans have the ability to re-grow the tips of injured fingers or toes. To better understand how they do this, Stanford researchers labeled specific tissue types of mice with fluorescent colors before cutting off a small part of the mice's toes. Over the course of three months, they examined the regenerated tissue.


Mice and some humans? why some humans and not every human. Hmm.

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