How a test for elastic fiber breakdown products in sputum could speed development of a treatment for pulmonary emphysema.

Pulmonary emphysema is a devastating disease for which there is no effective treatment. The development of therapeutic agents for this disorder has been hampered by the lack of clinical or biochemical tests which can rapidly evaluate drug efficacy. Since emphysema is associated with degradation of elastic fibers, the authors propose measuring the content of the elastin-specific amino acids, desmosine and isodesmosine, in sputum as a more immediate means of monitoring therapeutic interventions. Sputum samples would be chemically degraded to separate the component amino acids of elastic fibers, then measured for the total quantity of desmosine and isodesmosine, using any one of a number of established methods for quantifying these compounds, including radioimmunoassay, chromatography, or mass spectrometry. Such techniques allow for detection of nanogram quantities of desmosine and isodesmosine, and the procurement of ample amounts of induced sputum from the lower respiratory tract should improve the chances of detecting these amino acids. If proven valid, such a test could serve as a convenient marker for assessing lung injury in pulmonary emphysema, thereby facilitating rapid evaluation of new forms of treatment for this disease. The test might also prove to be a useful screening procedure for persons who smoke or otherwise have a greater than normal risk of developing emphysema.