Remodeling of bronchial and pulmonary muscular arteries in mild/moderate COPD

Pulmonary hypertension is well documented in severe COPD but little is known about vascular remodeling in mild/moderate patients. Aim:To investigate bronchial and pulmonary muscular arteries morphology and the expression of elastic fibers (EF) and collagen I in the lungs of mild/moderate COPD patients. Methods:Lung tissue of 18 COPD subject (FEV1:67±15%pred), 14 non-obstructed smokers(NOS) (FEV1:95±10%pred) and 11 never-smoking controls(CTRL) (FEV1:108±15%pred) was used to analyze the morphology of bronchial and pulmonary muscular arteries and the expression of EF and collagen I in the tunica intima, media and adventitia, using immune- and histochemistry and image analysis. Values (mean±SD) were expressed as (stained) area⁄vessel outer perimeter (μm2⁄μm) and as staining density (collagen I). Results:The intimal areas of pulmonary (CTRL=8.87±4.3, COPD=14.7±5, p=0.04) and the adventitia of bronchial arteries (CTRL=27.7±11.4, COPD=50.6±23.7, p=0.007) were larger in COPD patients than in CTRL. Higher EF expression was observed in adventitia of bronchial arteries of NOS group (8.8±13.2) than CTRL (3.1±1.3, p=0.04). The CTRL group had higher collagen I staining density in the adventitia of bronchial (CTRL=81.6±35.8; NOS=32.8±15; COPD=40.9±25.4, p=0.002) and pulmonary (CTRL=96.5±23.2; NOS=54.8±24; COPD=69.6±19.1, p=0.0005) arteries than NOS and COPD. Within COPD group, negative correlations were observed between the intimal area of pulmonary arteries and FEV1 (R=-0.57, p=0.04) and FEV1⁄FVC (R=-0.56, p=0.04). Conclusions:Remodeling of bronchial and pulmonary muscular arteries occurs in mild⁄moderate COPD, is associated with impaired lung function and it might contribute to the development of pulmonary hypertension.