Increased expression of matrix metalloproteinase-2 in nasal polyps.

Objective --The formation and growth of nasal polyps requires remodeling of the extracellular matrix. Matrix metalloproteinases (MMPs) are a family of endopeptidases that can collectively degrade almost all extracellular matrix components. The aim of this study was to investigate the role of MMPs in nasal polyps. Material and Methods --The expression of MMP-2 and -9 was investigated in the nasal polyps of 20 patients undergoing endonasal sinus surgery and compared with that in control nasal mucosal samples obtained from 20 non-allergic hypertrophic rhinitis patients. Tissue samples were either homogenized for reverse transcriptase polymerase chain reaction analysis or frozen for immunohistochemistry. Results --MMP-2 mRNA expression was observed only in the nasal polyp samples and not in the control tissues. MMP-9 mRNA was not expressed in either type of tissue. Similarly, MMP-2 expression was observed in the nasal polyps of chronic sinusitis patients but not in the inferior turbinate mucosa of the control subjects. MMP-2 positivity was present in basal cells in the surface epithelium and in infiltrating cells in subepithelial tissues. MMP-9-positive cells were not observed in either nasal polyps or inferior turbinates. These results suggest that MMP-2 expression is characteristic of nasal polyps. Conclusion --MMP-2 may play a role in the remodeling of nasal polyps. [ABSTRACT FROM AUTHOR]