In vivo relationship between collagenase‐2 and interleukin‐8 but not tumour necrosis factor‐α in chronic rhinosinusitis with nasal polyposis

Abstract

Background: The characteristic feature of chronic rhinosinusitis with nasal polyposis (CRSwNP) is eosinophilic inflammation of the sinus mucosa; a type of inflammation also seen in asthmatic airways. Similar histopathologic findings of airway remodelling are present in both diseases. Remodelling is tightly controlled by matrix metalloproteinases (MMP). Increase of collagenase‐2 (MMP‐8) expression in the bronchial epithelial cells has been described in asthmatic patients, but it has not been studied in CRSwNP. Methods: The concentrations and degree of activation of MMP‐8 were analysed by immunofluorometric assay and Western blotting, respectively, in sinus mucus samples from CRSwNP patients and in nasal lavages from healthy controls in relation to inductive cytokines interleukin‐8 (IL‐8) and tumour necrosis factor‐α (TNF‐α). Results: Significantly elevated levels of MMP‐8 and IL‐8 but not TNF‐α were found in CRSwNP patients relative to controls. In particular, the activation of mesenchymal‐type MMP‐8 but not polymorphonuclear‐type MMP‐8 was associated with elevated IL‐8 levels. Conclusions: The IL‐8 and MMP‐8 seemingly form an inductive cytokine‐proteinase cascade in CRSwNP pathogenesis. Together they provide a target for novel therapies and a diagnostic tool for monitoring CRSwNP treatment.