Expression of matrix metalloproteinase-2 and matrix metalloproteinase-9 in recurrent chronic rhinosinusitis with nasal polyposis

Matrix metalloproteinase (MMP) is involved in the upper airway remodeling process. We hypothesized that MMP had an additive effect on the formation of recurrent nasal polyp. We also investigated the association between the functional promoter polymorphism of MMPs and the intensity of labeling index. Expressions of MMP-2 and MMP-9 were assessed via immunohistochemical staining and compared between different groups, including recurrent nasal polyps, nonrecurrent nasal polyps, and control nasal mucosa. Two promoter functional single-nucleotide polymorphisms (rs3918242 for MMP-9 and rs243865 for MMP-2) were selected to correlate with staining intensity. Expression of MMP-9 was significantly enhanced in gland for recurrent nasal polyp (p = 0.016) and nonrecurrent nasal polyp (p = 0.005) compared to the control. MMP-2 positivity was significantly increased in surface epithelium for recurrent nasal polyp (p = 0.004) compared to the control (p = 0.061). However, there was no significant difference in MMP-9 and MMP-2 expressions between recurrent and nonrecurrent nasal polyps. Genetic polymorphism of MMP-2 and MMP-9 functional promoters was not associated with the intensity of labeling index. These results suggested that up-regulation of MMP-9 in gland and MMP-2 in surface epithelium was characteristic of both recurrent and nonrecurrent nasal polyps. Pathogenesis of recurrent nasal polyps may involve a mechanism other than MMP.