Bronchial asthma is an inflammatory disease of the airways that is associated with airway remodeling. The vascular endothelial growth factor (VEGF) is a potent, multifunctional cytokine that contributes to angiogenesis and inflammation. Matrix metalloproteinase-9 (MMP-9) is a major proteolytic enzyme that induces bronchial remodeling in asthma. However, there is no data available on the possible role of the VEGF or on the potential relationship between the VEGF and MMP-9 in acute asthma. Therefore, the VEGF was studied to determine whether or not it participates in airway inflammation during acute asthma. An additional aim of this study was to determine whether or not the VEGF levels correlated with the MMP-9 levels in the sputum of acute asthma patients.

Both the VEGF and MMP-9 levels were measured by an enzyme immunoassay and zymographic analysis in the sputum of patients with either stable asthma or with acute asthma. The VEGF and MMP-9 levels were also evaluated during a spontaneous asthma attack.

The VEGF levels were significantly higher in the sputum of acute asthmatic patients than in either the stable patients the control subjects. The VEGF levels in the sputum during asthma exacerbation were significantly higher than those on the remission days, and those levels decreased after decreased after asthma therapy. In acute asthmatic patients, the VEGF levels in the sputum correlated with the number of neutrophils and eosinophils. In addition, a significant correlation was established between the VEGF and MMP-9 levels in the sputum.

These results suggest that VEGF overproduction is associated with airway inflammation during acute asthma and is related to the MMP-9 function.