Remodeling in asthma and COPD--differences and similarities

Asthma and chronic obstructive pulmonary disease (COPD) are both inflammatory disorders. Diagnosis of these diseases is based upon limitation of expiratory airflow. The pathophysiological correlates to this impaired lung function are complex but they are associated with the development of structural changes in the airways and lung parenchyma. These remodeling processes differ between the two diseases. In asthma, airways obstruction is predominately located in the large airways, although recent studies indicate that inflammation and structural changes also is present in other compartments of the lungs. In COPD, remodeling of the small airways and lung parenchyma are the main correlates to the limitation of expiratory airflow. However, both asthma and COPD are heterogeneous disorders including various phenotypes and there is a considerable overlap between the two diseases.

In the present review, airway remodeling in asthma and COPD will be discussed in three different compartments of the airways: large airways, small airways and lung parenchyma. Different inflammatory cells will be mentioned, as well as markers of remodeling.

In COPD and severe asthma, current anti-inflammatory pharmacotherapy does not restore lung function impairment fully. It is therefore recognized that research aiming to explore mechanisms of airway remodeling should be encouraged.