Analysis of syndecan-1 and TGF-β expression in the nasal mucosa and nasal polyps

Abstract

Objective Increased understanding of cytokines and their associated proteoglycans will contribute to the investigation of the formation of nasal polyps. Recently, some studies have suggested that syndecan-1 ectodomains are shed in response to low respiratory infection, but no studies regarding nasal and paranasal diseases have been reported. Transforming growth factor-beta (TGF-β) is involved in the regulation of nasal polyps, especially in processes crucial to the initiation, maintenance, and resolution of inflammatory responses. In the nasal mucosa and nasal polyps, we analyzed the expression of syndecan-1, which readily promotes infection, and TGF-β, which plays a role in syndecan-1 activity. Methods Fifteen patients who underwent turbinectomy for the treatment of nasal obstruction and seventeen patients with nasal polyps who underwent nasal endoscopic sinus surgery were included in this study. The localization of syndecan-1 and TGF-β in the nasal mucosa and nasal polyps was investigated by immunohistochemistry, and mRNA transcript levels of syndecan-1 and TGF-β were examined using quantitative real-time PCR. Results Immunohistochemical staining revealed that the expression of syndecan-1 in the nasal mucosa and nasal polyps was co-localized with TGF-β. The mean mRNA expression values for syndecan-1 and TGF-β were higher in nasal polyps compared to the nasal mucosa. Conclusions This is the first report showing expression of syndecan-1 in the nasal mucosa and nasal polyps. In nasal polyps, syndecan-1 expression may be increased by an unknown mechanism, permitting infection and inducing larger nasal polyps. We hypothesize that the accumulation of TGF-β, which is involved in the pathophysiological development of nasal polyps, may result in a change in the binding properties of syndecan-1 at inflammatory sites.