Proteoglycan changes in the extracellular matrix of lung tissue from patients with pulmonary emphysema

To characterize the changes in the extracellular matrix in smoking-related pulmonary emphysema, we undertook immunohistochemical studies in lung tissu es from controls (n = 7), from patients with mild (n = 11) and severe (n = 8) emphysema, and from patients with lung fibrosis (n = 6). We studied coll agens, laminin, flbronectin, proteoglycans (PGs), and beta 1-integrins. The majority of the patients with severe emphysema showed diminished staining for the interstitial PGs, decorin and biglycan, in the peribronchiolar area , compared with patients in the control and fibrosis groups. Only a minorit y of patients with mild emphysema showed this diminished staining. In contr ast, decorin and biglycan were well preserved in the perivascular area of a ll of the specimens from the emphysema group. Heparan sulfate PG staining w as diminished in the respiratory airspace walls of patients with emphysema and fibrosis. Staining for Types I, III, and IV collagen, as well as for la minin, fibronectin, and the integrins, showed no differences between the fo ur groups. The specific loss of interstitial PGs may be crucial for elastic recoil loss and subsequent bronchiolar obstruction, as seen in patients wi th smoking-related emphysema.