Versican and collagen-III expression in bronchial and pulmonary muscular arteries in COPD patients

Abstract

Background: We demonstrated that COPD patients have thicker bronchial and pulmonary muscular arteries (MA) compared with never and non-obstructed smokers. The composition of the extracellular matrix of these altered MA has been not fully described. Objectives: To investigate the expression of versican and collagen-III in bronchial and pulmonary MA in the lungs of mild/moderate COPD patients. Methods: Eighteen mild/moderate COPD subjects (67±8y, FEV 1 : 67±15%pred), 14 non-obstructed smokers (64±8y, FEV 1 : 95±10%pred) and 11 never-smoking controls (CTRL) (51±12y, FEV 1 : 108±15%pred) were studied. Lung tissue obtained during surgery (ethical approval obtained) was used to analyze the expression of versican and collagen III in the tunica intima/media (measured together) and adventitia, using immunohistochemistry and image analysis. Fractional areas of each layer were expressed as mean±SD. Results: COPD patients showed higher versican expression in the adventitia of bronchial (COPD: 36.9±20, CTRL:19.4±9, p=0.03) and pulmonary (COPD:47.5±15, CTRL:26.4±17, p=0.008) MA compared to CTRL. Positive correlations were observed between the expression of versican in adventitia of both bronchial and pulmonary MA and age, FEV 1 and FEV 1 /FVC. No differences were observed in the expression of collagen III among the three groups. However, negative correlations between collagen III expression in the intima/media of bronchial and pulmonary MA and pack-years were observed. In pulmonary MA, the collagen III expression was also negatively associated with FEV 1 /FVC. Conclusions: Increased versican content and collagen III composition in the MA of COPD patients are associated with clinical/functional parameters.