Evidence of angiogenesis in bronchial biopsies of smokers with and without airway obstruction.

An immunohistochemical study was performed on bronchial biopsies taken from 8 non-smokers and 18 smokers divided, according to global health initiative on obstructive lung diseases (GOLD) classification of COPD, into two groups, GOLD 0 and GOLD 2, each of 9 subjects. The number of vessels and the percentage of vascular area in the lamina propria were evaluated by mAb anti-collagen IV. Cellular expression of VEGF and vascular expression of αvβ3 integrin were evaluated by the specific monoclonal antibodies. An image processing and analysis system was used to quantify the immunohistochemical data. The number of vessels, the vascular area, the cellular expression of VEGF, the number and percentage of αvβ3 positive vessels were significantly higher in GOLD 0 and in GOLD 2 smokers than in non-smokers. The comparison between GOLD 0 and GOLD 2 smokers did show a weak but significantly lower number of vessels in GOLD 2, while the vascular area and the percentage of αvβ3 positive vessels did not differ between the two groups. A higher cellular VEGF expression was detected in the GOLD 2 than in the GOLD 0 group. Angiogenesis of bronchial vessels is a component of the airway remodelling occurring in symptomatic smokers with normal lung function and with COPD, it seems independent by the development of airway obstruction and not related to its severity.