Sunday, April 21, 2013

Fat-forming cells found important for muscle repair

The body contains many different highly specialized cells that all have their own function in the various organs we have. Constant renewal is necessary to keep tissues healthy: so-called progenitor cells help replenish tissues and organs by replicating themselves and forming new highly specialized cells, depending on the context they find themselves in. For example, we have progenitor cells that help form fat cells. Despite the fact that most people do not require additional formation of fat, scientists have discovered that such progenitor cells can also help restoring damaged muscles.

Progenitor cells that are involved with making new fat cells are called fibro/adipogenic cells, or FAP cells. Their activity increases with age, oddly enough, and also with prolonged immobility. Although most progenitor cells have only the capability to create new cells from the type that they were programmed for, this is not the case for FAP cells: earlier studies have shown that they are also involved with regenerating connective tissues.

In a recently published study from the University of California in San Francisco, scientists have shown that FAP cells have an additional, important role. In the case of muscle damage, they work closely together with eosinophils, which are part of the first line of defense of the immune system. Together, they help instigate muscle repair by creating new cells. Eosinophils produce a chemical messenger known as IL-4, and this in turn stimulates FAP cells to expand in numbers and specialize into muscle cells, instead of fat cells.

There are many causes of muscle damage, such as a traumatic experience or intoxication. In such cases, it is paramount that the damaged tissues are restored. Equally so, it is important to learn how this is governed in the body, so that we may use these principles to enhance regeneration of muscles, but perhaps also other tissues. In this case, scientists have discovered one of the most important sources of muscle repair. It is interesting to note that the repairs come from a source that one would not expect to be involved.

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