Effect of beclomethasone dipropionate on basic fibroblast growth factor levels in induced sputum samples from asthmatic patients

Background: Airway remodeling in asthma refers to certain structural changes and is regulated by several growth factors. One molecule of potential relevance to these pathologic changes is basic fibroblast growth factor (bFGF). Objectives: To examine the relationship between bFGF levels and type III collagen synthesis in asthmatic airways and the effect of inhaled corticosteroid therapy on bFGF levels. Methods: We simultaneously measured bFGF, vascular endothelial growth factor (VEGF), and procollagen type 111 peptide (P-III-P) levels in induced sputum samples from 17 asthmatic patients and 10 controls. Sputum induction was performed before and after I year of inhaled beclomethasone dipropionate therapy. Results: Before beclomethasone dipropionate therapy, mean (SD) VEGF and bFGF levels were significantly higher in asthmatic patients (VEGF: 4,270 [650] pg/mL; bFGF: 46.4 [20.0] pg/mL; P < .001 for both) than in controls (VEGF: 1,730 [1,140] pg/mL; bFGF: 6.0 [3.0] pg/mL). Although P-III-P was detected in none of the controls, P-III-P levels could be measured in all the asthmatic patients. No significant correlation was found between P-III-P and VEGF levels in asthmatic patients. However, a close correlation was found between bFGF and P-III-P levels in these patients (r = 0.84; P < .001). After 1 year of beclomethasone dipropionate therapy. VEGF levels were significantly decreased, whereas bFGF and P-III-P levels did not differ before vs after therapy. There remained a significant correlation between bFGF and P-III-P levels even after beclomethasone dipropionate therapy. Conclusions: A close correlation between bFGF and P-III-P levels was observed in asthmatic airways. However, corticosteroid therapy might not prevent airway remodeling via the bFGF-dependent pathway.