Vascular remodelling in COPD airways

The role played by bronchial vasculature in the remodelling process occurring in the airways of smokers with and without COPD has been poorly investigated.Vascular endothelial growth factor (VEGF) is the most potent and widely distributed angiogenic factor known to date. αvβ3 integrin, an adhesion molecule expressed only at low levels on resting endothelium, is upregulated in new capillaries proliferating in response to angiogenic stimuli. We performed an immunohistochemical study on bronchial biopsies taken from 8 non-smokers, 9 smokers with normal lung function (GOLD 0) and 9 smokers with moderate COPD (GOLD 2). We evaluated in the lamina propria: 1) the number of vessels and the percentage of vascular area 2) the cellular expression of VEGF and 3) the vascular expression of αvβ3. Results did show that the number of vessels, the vascular area, the cellular expression of VEGF, the number and percentage of αvβ3 positive vessels were significantly higher in both GOLD 0 and 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 VEGF expression was detected in the GOLD 2 than in the GOLD 0 group. Our data suggest that angiogenesis of bronchial vessels is a significant component of the airway remodelling occurring in symptomatic smokers with normal lung function and with COPD. The angiogenetic process seems to be independent by the development of airway obstruction and not related to its severity.