GELATINOLYTIC AND TYPE-IV COLLAGENOLYTIC ACTIVITY IN BRONCHIECTASIS

To evaluate the extracellular matrix (ECM) degradation in bronchiectas is (BE), the level of gelatinolytic and type IV collagenolytic activit y was analyzed in bronchoalveolar lavage fluid (BALF) by using zymogra phies. The BALF of patients with bronchiectasis revealed a high gelati nolytic 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 a nd bronchitis, mucopurulent and purulent sputum production, and saccul ar changes of bronchi having high activities of both 92-kd and 72-kd g elatinases 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 th e 92-kd area. These findings suggest a role for the matrix metalloprot einases MMP-2 (72-kd gelatinase/type IV collagnease) 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 associat ed with the presence of low-molecular weight gelatinases reflecting in vivo metalloproteinase activation and/or the presence of microbial-de rived gelatinolytic proteinases.