Heme oxygenase-1 expression in chronic rhinosinusitis with eosinophilic infiltration

Objectives

Chronic rhinosinusitis (CRS) with eosinophilic infiltration is a type of intractable rhinosinusitis often associated with asthma. The oxidants are well known to induce aggravate asthma. Heme oxygenase-1 (HO-1), a cytoprotective enzyme against oxidant, has been extensively studied in airway diseases. However, no study that observed HO-1 in both epithelial and subepithelial tissues of CRS has been reported.

Methods

Part of each specimen derived from the nasal polyps of CRS with and without eosinophilic infiltration was promptly fixed for hematoxylin–eosin staining and immunohistochemical analysis for HO-1 and macrophages.

Results

We found that the expression of HO-1 in the epithelial layers of CRS without eosinophilic infiltration was significantly enhanced as compared with that of CRS with eosinophilic infiltration. On the other hand, the number of macrophages with HO-1 positive reactions was significantly greater in CRS with eosinophilic infiltration compared with CRS without eosinophilic infiltration.

Conclusions

Our study suggests that both a reduction of HO-1 expression in epithelial cells and an increase of infiltration of macrophages positive for HO-1 are related to the epithelial damage of CRS with eosinophilic infiltration.