Circulating TGF-β1 Levels: Linking Muscle and Trauma

Transforming growth factor-beta 1 (TGF-β1) is a multifunctional growth factor that plays a key role in a variety of human tissues. Three TGF-β1 target cell types are of particular relevance to muscle trauma, involving TGF-β1 effects on (1) inflammatory cells, (2) myocytes, and (3) connective tissue cells. Normal wound healing process with proper immune system participation allows injured muscle to be restored to its original state, whereas abnormal wound healing leads to aberrant mesenchymal differentiation and resultant fibrosis. As the pleiotropic activities of TGF-β1 are highly context-dependent, its role in muscle regeneration following injury is complex, and its potential as a treatment option without unwanted side effects remains unsettled. Interestingly, recent research findings have suggested that circulating TGF-β1 levels are an indicator of disease status. This chapter provides an overview of these findings and proposes an avenue toward validating circulating TGF-β1 as prognostic biomarker following muscle trauma.