Gelatinolytic and type IV collagenolytic activity in bronchiectasis

To evaluate the extracellular matrix (ECM) degradation in bronchiectasis (BE), the level of gelatinolytic and type IV collagenolytic activity was analyzed in bronchoalveolar lavage fluid (BALF) by using zymographies. The BALF of patients with bronchiectasis revealed a high gelatinolytic and type IV collagenolytic activity whereas no such activities were detected in BALF of the healthy controls. Furthermore, the level of degradative activity correlated with the severity of disease with a spectrum varying from patients characterized by frequent pneumonia and bronchitis, mucopurulent and purulent sputum production, and saccular changes of bronchi having high activities of both 92-kd and 72-kd gelatinases type IV collagenases (corresponding to the neutrophil type MMP-9 and fibroblast type MMP-2 activities, respectively) to patients having few clinical symptoms and displaying only a weak activity at the 92-kd area. These findings suggest a role for the matrix metalloproteinases MMP-2 (72-kd gelatinase/type IV collagenase) and MMP-9 (92-kd gelatinase/type IV collagenase) in the degradation of ECM of bronchial wall and lung tissue. In addition, severe bronchiectasis was associated with the presence of low-molecular weight gelatinases reflecting in vivo metalloproteinase activation and/or the presence of microbial-derived gelatinolytic proteinases.