Our findings are in agreement with the reported elevation of VEGF in the sputum of healthy smokers and with the decrease of both VEGF and VEGF receptor expression in COPD and with the in vitro study by Volpi et al demonstrating increased production of VEGF in pulmonary smooth muscle cells and fibroblasts in response to cigarette smoke extract, acrolein, crotonaldehyde and 4-HNE treatments [31]. Here, VEGFA is linked to chronic obstructive pulmonary disease.