Rationale: Vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) are mediators of airway inflammation and remodeling in asthma.
Objectives: This study investigates a potential relationship between VEGF and MMP-9, and the mechanisms by which VEGF signaling regulates MMP-9 expression in asthma.
Methods: We evaluated whether levels of VEGF correlated with levels of MMP-9 in the sputum of asthma patients, and the effect of VEGF receptor inhibitors on MMP-9 expression in murine model of asthma.
Measurements and main results: We have found that levels of VEGF and MMP-9 are significantly higher in the sputum of patients with asthma than in healthy control subjects, and a significant correlation is found between the levels of VEGF and MMP-9. This study with the ovalbumin-induced model of asthma revealed the following typical pathophysiologic features of asthma in the lungs: increased numbers of inflammatory cells of the airways, airway hyperresponsiveness, increased vascular permeability, and increased levels of MMP-9 and VEGF. Administration of VEGF receptor inhibitors reduced the pathophysiologic signs of asthma and decreased the increased expression of MMP-9 after ovalbumin inhalation.
Conclusions: These results indicate that there is a close relationship between VEGF and MMP-9 expression and that inhibition of VEGF receptor down-regulates the expression of MMP-9. These findings suggest that VEGF signaling regulates MMP-9 expression and plays a critical role in initiation and maintenance of asthma.