Stem cell researchers give old musc...( Berkeley - Old muscle got a shot of ...)

Berkeley - Old muscle got a shot of youthful vigor in a stem cell experiment by bioengineers at the University of California, Berkeley, setting the path for research on new treatments for age-related degenerative conditions such as muscle atrophy or Alzheimer's and Parkinson's diseases.

In a new study to be published June 15 in an advanced online issue of the journal Nature, researchers identified two key regulatory pathways that control how well adult stem cells repair and replace damaged tissue. They then tweaked how those stem cells reacted to those biochemical signals to revive the ability of muscle tissue in old mice to repair itself nearly as well as the muscle in the mice's much younger counterparts.

Irina Conboy, an assistant professor of bioengineering and an investigator at the Berkeley Stem Cell Center and at the California Institute for Quantitative Biosciences (QB3), led the research team conducting this study.

Because the findings relate to adult stem cells that reside in existing tissue, this approach to rejuvenating degenerating muscle eliminates the ethical and medical complications associated with transplanting tissues grown from embryonic stem cells.

"We are one step closer to having a point of intervention where we can rejuvenate the body's own stem cells so we don't have to suffer from some of the debilitating diseases associated with aging," said the study's lead author, Morgan Carlson, a recent Ph.D. graduate of Conboy's lab.

The researchers focused on the interplay of two competing molecular pathways that control the stem cells, which sit next to the mature, differentiated cells that make up our working body parts. When the mature cells are damaged or wear out, the stem cells are called into action to begin the process of rebuilding.

"We don't realize it, but as we grow our bodies are constantly being remodeled," said Conboy. "We are constantly falling apart, but we don't n
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