26 - Airway Remodelling

Abstract

Publisher Summary Structural changes in the airway walls involving extracellular-matrix remodeling are prominent features of asthma. These changes are driven by the mediators released as a consequence of chronic allergic inflammation. Changes in a matrix have the capacity to influence airway function in asthma. However, it is not clear how each of the many changes that occur in the airway wall contribute to alter airway function in asthma. Conversely, geometric considerations would result in exaggerated airway narrowing for a given degree of smooth muscle shortening as the airway wall is thickened by the deposition of these molecules internal to the smooth muscle. Elastin and cartilage degradation in the airway walls would be expected to result in decreased airway wall stiffness and increased airway narrowing for a given amount of force generated by the smooth muscle. Degradation of matrix associated with the smooth muscle may both decrease the stiffness of the parallel elastic component and uncouple smooth muscle from the load provided by lung recoil, thereby allowing exaggerated smooth-muscle shortening. An increase in muscle mass may be associated with an increase, a decrease, or no change in smooth-muscle contractility. If an increase in muscle mass is not associated with any other phenotypic changes, it would be expected to contribute to exaggerated airway narrowing.