New approaches to the management of COPD

Airflow limitation in COPD is a result partially of bronchospasm, but it is also caused by a reduction in airway caliber, the number of small airways, airway collapse because of loss of connective tissue support, excess mucus in the airways, and edema of the airway wall. Structural changes also occu r because of long-term destruction of interstitial connective tissue, inclu ding elastin. Therefore, in addition to the traditional aim of reversing br onchospasm with bronchodilators, disease-modifying approaches are being inv estigated. The enzyme neutrophil elastase is implicated in the induction of bronchial disease causing structural changes in lungs, impairment of mucoc iliary clearance, and impairment of host defenses. The precise mechanism pa thway of neutrophil elastase is uncertain, but the effects of influencing t he pathway in order to slow disease progression are being investigated. Oxi dants may also have a role in the development of COPD, with increased level s activating airway cells and cytokine production.