Abstract
Rationale: Vascular remodeling plays a central role in asthma and COPD and bradykinin (BK) is a vasoactive peptide involved in asthma. Objective: To investigate the role of angiogenic factors in relation to BK receptors in asthma and COPD.
Methods: Bronchial biopsies from 33 COPD subjects, 24 old (>=50yrs) asthmatics (OA), 18 old control smokers (OCS), 11 old control non-smokers (OCNS), 15 young (<=40yrs) asthmatics and 10 young control non-smokers were immunostained for CD31, VEGF, angiogenin and BK receptors (B2R and B1R). Fibroblast co-localization of relevant molecules was performed by immunofluorescence. BK-induced VEGF and angiogenin release was studied (ELISA) in human bronchial fibroblasts from asthma and COPD.
Results: In bronchial submucosa of OA, CD31+ and VEGF+cell numbers were higher than OCNS (p<0.05). Angiogenin+, B2R+and B1R+cell numbers in OA were higher than in OCNS, OCS and COPD (p<0.01). Angiogenin+ cell numbers were higher in COPD than both OC groups (p<0.05). In all asthmatics the number of B2R+ cells was positively related to the number of B1R+cells (rs=0.43), angiogenin+cells (rs=0.42) and CD31+cells (rs=0.46) (p<0.01). Angiogenin+ cell numbers were negatively related to FEV1(rs=-0.415, p=0.008). We showed that most bronchial asthmatic fibroblasts expressed B2R, VEGF and angiogenin. BK (10-6M) induced significant angiogenin release in fibroblasts from asthma and COPD.
Conclusions: Unlike COPD, this study suggests the involvement of BK receptors in bronchial vascular remodeling in asthma.
- © 2013 ERS