Scientists have shown that, contrary to prevailing wisdom, muscles contain stem cells that can repair, replace and strengthen injured tissue. Writing in Nature Stanford researcher Helen Blau and her colleagues have identified a collection of chemical markers that can be used to identify a population of muscle stem cells.
Dubbed "satellite cells" because these small round bodies usually loiter at the edges of muscles, when injected into an injured muscle they can rapidly begin to divide, producing more stem cells and new muscle tissue.
The team made the discovery by genetically labelling the cells with a coloured marker protein before injecting them into mice with damaged leg muscles. This technique enabled the researchers to follow the progress of the same mouse over a period of time by using a sensitive camera that could pick up the increasing intensity of the coloured stem cells as they grew.
"We were able to show that the injected cells increased their own numbers, contributed to existing muscle and also produced entirely new muscle in these mice," points out Blau. The results are very exciting because now researchers are able to readily identify the muscle stem cells they can turn their attention to discovering ways to activate them in people with muscle-wasting diseases, or use them to repair muscles in trauma patients.
"That's the next step," says Blau.