Increased expression of matrix metalloproteinase-9 in nasal polyps

To investigate the role of gelatinases in nasal polyposis, a common and dis abling airway disease characterized by chronic inflammation and tissue remo delling, matrix metalloproteinase-2 (MMP-2) and MMP-9 expression was invest igated in the nasal polyps (NP) of 24 patients undergoing ethmoidectomy and compared with 15 control nasal mucosal (CM) samples obtained from snorers during turbinectomy, Tissue samples were either frozen for enzymatic analys is or paraffin was-embedded for immunohistochemistry, Zymography and quanti tative image analysis showed that MMP-9 active forms were significantly inc reased (p<0.05) in NPs compared to CM (44 +/- 40 versus 13 +/- 19 x 10(3) A U/10 <mu>g protein), while MMP-2 expression was similar in both tissues. Co ncomitant studies of gelatinase immunoexpression showed that MMP-9 expressi on was enhanced (4- to 16-fold) in surface epithelium, glands (p<0.05), and submucosal inflammatory cells (p<0.05). In addition, MMP-9 positivity was markedly increased in endothelial cells (p<0.01). In situ zymography demons trated marked gelatinolytic activity, consistent with the immunolocalizatio n of MMP-2 and MMP-9. These results suggest up-regulation of active MMP-9 i n the glands and vessels characteristic of NPs, It is concluded that MMP-9 may play a role in the upper airway remodelling observed during nasal polyp osis. Copyright (C) 2000 John Wiley & Sons, Ltd.