[Role of bronchial smooth muscle in inflammation]

We now have to consider the airway smooth muscle as an actor of the bronchial inflammation in asthma. In addition to its bronchoconstricting role in response to mediators secreted by the adjacent cells and tissues, that may be considered as to be passive regarding the airway inflammation, the airway smooth muscle may now be considered as pro-inflammatory, since it has the potential of synthesizing and secreting a variety of chemokines and growth factors that will favor cell proliferation, and attraction of inflammatory cells. The airway smooth muscle may modify its phenotype from a contractile to a secretory or a proliferative phenotype. These differentiation states of the bronchial smooth muscle may be studied experimentally by culturing the airway smooth muscle. The demonstration of the occurrence and/or coexistence of such differentiation states in vivo will help understand the exact role of the bronchial smooth muscle in the airway inflammation in asthma.