The Need for Real-Time Measurement of Lung Injury in Developing an Effective Treatment for Pulmonary Emphysema

Chronic obstructive pulmonary disease (COPD) is characterized by diffuse inflammation of the airways and parenchyma of the lung. In its most devastating form, the disease produces widespread emphysematous changes in the lung, characterized by dilatation and rupture of alveoli, marked impairment of gas exchange, and eventual respiratory failure. The development of therapeutic agents for COPD, and pulmonary emphysema in particular, has been hampered by the lack of clinical or biochemical tests which can rapidly and reliably determine drug efficacy. The only recognized endpoint for evaluating new treatments, pulmonary function studies, may take years to detect a significant effect. This delay is due to the fact that pulmonary emphysema progresses at a relatively slow rate, and the available methods for measuring the loss of lung function are not particularly sensitive. Since elastic fiber degradation is an important feature of pulmonary emphysema, the authors propose measuring specific breakdown products of these fibers in sputum as a more immediate means of monitoring therapeutic interventions. In addition to facilitating rapid evaluation of new forms of treatment for pulmonary emphysema, this assay might also prove to be a useful screening procedure for persons who smoke or otherwise have a greater than normal risk of developing this disease.