Expression of heme oxygenase-1 in eosinophilic and non-eosinophilic chronic rhinosinusitis with nasal polyps: modulation by cytokines.

Background: Oxidative stress is characteristic of chronic airway inflammatory diseases such as asthma, chronic obstructive pulmonary disease and chronic rhinosinusitis with nasal polyps (CRSwNP). Heme oxygenase (HO)-1 has been proposed to be a cytoprotective enzyme against oxidative stress in CRSwNP. However, the expression and regulation of HO-1 in eosinophilic CRSwNP (ECRS) and non-eosinophilic CRSwNP (non-ECRS) subsets has not been well documented.

Methods: Nasal polyps and uncinate process tissues were enrolled from 40 CRSwNP patients (ECRS, 17; non-ECRS, 23) and 20 control subjects, respectively. The messenger RNA (mRNA) and protein expression of HO-1 was examined using qRT-PCR, immunohistochemistry, and Western blot staining. Moreover, the stimulatory effects of several cytokines (interferon γ [IFN-γ], interleukin [IL]-5, and IL-13, etc.) on HO-1 mRNA expression in cultured nasal explants were evaluated.

Results: The mRNA and protein expression of HO-1 was significantly increased in polyp tissues compared with healthy controls (p < 0.05), and the non-ECRS subset showed significantly increased HO-1 expression compared with the ECRS subset (p < 0.05). Moreover, in cultured nasal explant, HO-1 mRNA was significantly upregulated in the presence of IFN-γ, IL-27, IL-5, IL-13, and IL-17A, but was significantly inhibited by transforming growth factor β1 (TGF-β1) (p < 0.05).

Conclusion: Our findings indicate that HO-1 was differentially expressed and regulated in ECRS and non-ECRS patients.