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 (w0) and after 2 (w2) and 12 (w12) 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 w2 (8.0±2.9, p=0.001) and w12 (10.0 ± 2.3, p<0.003) compared to w0 (25.5 ± 8.4); and also decreased the expression of MMPs and TIMP-1 in eosinophils at w2 and w12 compared to w0 (p<0.05). In the epithelium, corticosteroids increased MMP-7 and TIMP-1 at w2 and w12, while decreased MMP-9 at w12 (p<0.05). In vessels, corticosteroids increased MMP-9 at w2 and decreased MMP-1 at w12 (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.