Epithelial-mesenchymal transition in chronic rhinosinusitis (CRS) and the prognostic value of α-SMA in postoperative outcomes of patients with CRS

Tissue remodeling is the pathological basis of the symptoms encountered in chronic rhinosinusitis (CRS). Epithelial-mesenchymal transition (EMT) may participate in this process. The present study was designed to investigate the involvement of EMT in CRS. In addition, the prognostic value of the EMT biomarker alpha-smooth muscle actin (alpha-SMA) was assessed in patients with CRS who underwent endoscopic sinus surgery (ESS). A total of 13 patients with CRS without nasal polyps (CRSsNP), 13 patients with CRS with nasal polyps (CRSwNP) and 13 control subjects were enrolled. The expression of EMT markers was determined in sinonasal specimens by qPCR, western blot and immunofluorescence assays. EMT features were evaluated in primary nasal epithelial cells (NECs) with transforming growth factor (TGF)-beta 1 stimulation. The associations were assessed between alpha-SMA expression and the clinical features of CRS. Epithelial and mesenchymal markers were overexpressed in the sinonasal specimens of both CRSsNP and CRSwNP patients. Alterations in the expression pattern were more apparent in the CRSsNP patients. Following incubation of primary NECs with TGF-beta 1, a mesenchymal shape was acquired. In addition, NECs that co-expressed alpha-SMA and cytokeratin were readily detected and the protein levels of alpha-SMA were elevated. In contrast to alpha-SMA, the levels of E-cadherin were decreased. The protein levels of alpha-SMA were negatively correlated with endoscopic scores and several postoperative symptoms. In conclusion, partial EMT occurred in patients with CRS, notably in CRSsNP patients. Moreover, primary NECs could undergo EMT following TGF-beta 1 treatment in vitro. In addition, alpha-SMA could be considered an efficient predictor for postoperative endoscopic and symptomatic outcomes in patients with CRS treated with ESS.