133 Corticosteroid Rreatment Reduces Tissue Eosinophilia and the Expression of Matrix Metalloproteinases (MMP-1, MMP-2, MMP-7, MMP-9) and Their Tissue Inhibitor (TIMP-1) in Nasal Polyps

BACKGROUND: Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) may play an important role in both inflammation and remodeling of nasal polyposis. The aim of the current study was to compare the expression levels of MMPs and TIMP-1 between nasal mucosa and polyps, and to evaluate the effect of corticosteroid treatment in their expression in nasal polyps. METHODS: Nasal mucosa (NM, n = 12) were obtained from patients undergoing nasal corrective surgery while nasal polyp biopsies (NP, n = 33) were obtained from patients before (week 0) and after 2 (week 2) and 12 (week 12) weeks of corticoisteroid treatment (oral prednisone for 2 weeks and intranasal budesonide for 12 weeks). Matrix metalloproteases (MMP-1, MMP-2, MMP-7, MMP-9) and tissue inhibitor of metalloproteinases type 1 (TIMP-1) expression was evaluated by immunohistochemistry in tissue structural cells (epithelium, glands, vessels) and eosinophils. RESULTS: MMP and TIMP-1 expression were found in the epithelium, glands, vessels (in both NM and NP), and in eosinophils (only in NP). Expression of MMP-7 in epithelium (34% of tissues) and MMP-9 (19%) in glands was lower (P < 0.05) in NP than in NM (78 and 67%, respectively). Corticoisteroid treatment reduced tissue eosinophilia (Eos/5 fields) at week 2 (8.0 ± 2.9, P = 0.001) and week 12 (10.0 ± 2.3, P < 0.003) compared to week 0 (25.5 ± 8.4); and also decreased the expression of MMPs and TIMP-1 in eosinophils at week 2 and week 12 compared to week 0 (P < 0.05). In the epithelium, corticosteroids increased MMP-7 and TIMP-1 at week 2 and week 12, while decreased MMP-9 at week 12 (P < 0.05). In vessels, corticosteroids increased MMP-9 at week 2 and decreased MMP-1 at week 12 (P < 0.05). No effects were found in the glands. CONCLUSIONS: Treatment of nasal polyposis with corticosteroids reduces both tissue eosinophilia and MMP expression in eosinophils while modifying the expression of remodeling markers in nasal polyp structural cells.