June 25, 2009
New research published online in the journal Nature suggests that adult stem cells, not embryonic stem cells, are appropriate for use in therapies for repairing damaged and diseased muscle. Researchers from Maryland and Indiana report that experiments with mice show the genes involved in muscle development are turned off soon after birth, and are not used by adult stem cells that repair muscle. Lead author Christoph Lepper said "I thought that if they are so important in the embryo, they must be important for adult muscle stem cells. I was totally surprised to find that the muscle stem cells are normal without them."
In their paper the authors note:
"Changes in genetic requirement for muscle stem cells from embryonic to juvenile to adult stages elucidate the inadequacy of applying knowledge gained from developmental studies to adult stem-cell biology. Our discovery should encourage future investigations into how widespread genetic transitions may occur in different adult stem-cell types. Age-dependent differences in stem-cell properties should also urge careful consideration of the age of stem cells used in transplantation-based regenerative medicine."
The implications? Studying embryonic stem cells is an inadequate substitute for directly studying how adult stem cells carry out their normal repair functions in the body, and embryonic stem cells themselves are inadequate substitutes for adult stem cells in medical therapies. In other words, don't use a sledgehammer instead of precision equipment.