Vascular endothelial growth factor correlates with matrix metalloproteinase-9 in the pleural effusion

Vascular endothelial growth factor (VEGF) is a potent, multifunctional cytokine that contributes to angiogenesis and inflammation. Matrix metalloproteinase-9 (MMP-9) is one of the major proteolytic enzymes that degrade various components of the extracellular matrix. Few data are available on the potential relationship between VEGF and MMP-9 in the accumulation of pleural effusion. We examined levels of VEGF and MMP-9 by means of enzyme immunoassay, zymographic analysis, and Western blot analysis in the patients with liver cirrhosis, tuberculosis, or lung cancer. The levels of VEGF and MMP-9 were significantly increased in the pleural fluids and sera of patients with tuberculosis and were even higher in patients with lung cancer compared with the patients with liver cirrhosis. A significant correlation was established between the level of VEGF and the level of MMP-9 in the pleural effusion. These results suggest that overproduction of VEGF and MMP-9 is associated with accumulation of the pleural effusion in tuberculosis and lung cancer. The relationship between VEGF and MMP-9 in the pleural effusion may have a role in the pathogenesis of pleural fluid formation.