Background: Chronic rhinosinusitis (CRS) and nasal polyposis (NP) are histopathologically characterized by different gross morphological aspects. Transforming growth factor (TGF) beta1 plays an important role in tissue remodeling, which is poorly understood in chronic diseases of the sinuses.
Methods: The expression of TGF-beta1 was analyzed by enzyme-linked immunosorbent assay, quantitative reverse-transcription polymerase chain reaction, and immunohistochemistry in nasal tissue from controls (n = 6), CRS (n = 19), or NP (n = 19).
Results: CRS presented significantly higher concentrations of TGF-beta1 at protein (p = 0.0008) and mRNA levels (p = 0.025) when compared with NP samples. In CRS, TGF-beta1+ staining of the extracellular matrix was found abundantly and related to fibrosis. In contrast, no TGF-beta1 staining was found in the pseudocyst areas in NP.
Conclusion: CRS was histologically characterized by fibrosis, which was reflected by a significantly higher expression of TGF-beta1 at RNA and protein levels when compared with NP. We show that TGF-beta1 expression is related to fibrosis, differentiating CRS without polyps from NP.