Increased Expression of Vascular Endothelial Growth Factor and Hypoxia Inducible Factor-1α in Lung Tissue of Patients with Chronic Bronchitis

Objectives: Vascular 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 Methods: We 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.

Results: Compared 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).

Conclusion: VEGF 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.