Increased expression of vascular endothelial growth factor and hypoxia inducible factor-1α in lung tissue of patients with chronic bronchitis

Abstract

ObjectivesVascular endothelial growth factor (VEGF) seems to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD), but its site-specific expression in lung tissue and the relationship with hypoxia inducible factor-1 alpha (HIF-1α) expression in chronic bronchitis (CB) type COPD have not been studied. Design and methodsWe evaluated the expression of VEGF and its receptors in various compartments of lung tissue in three groups: non-smokers with normal lung function (non-smokers, n=10), smokers without COPD (healthy smokers, n=10) and smokers with CB (CB, n=10), using immunohistochemical staining and Western blotting. The expression of HIF-1α was assessed by enzyme-linked immunosorbent assay. ResultsCompared with healthy smokers, VEGF expression in CB was significantly increased in bronchiolar epithelium, vascular endothelium and vascular smooth muscle (p<0.05). VEGF receptor (VEGFR)-2 expression in CB was also increased in bronchiolar smooth muscle, vascular endothelium and vascular smooth muscle compared with healthy smokers (p<0.05). The level of HIF-1α was increased in CB compared with healthy smokers and positively correlated with those of VEGF (r=0.64, p<0.05). ConclusionVEGF and VEGFR-2 expressions were up-regulated in CB and increased expression of VEGF was related with HIF-1α. HIF-1α-regulated VEGF overexpression may be a characteristic of chronic bronchitis.