RESUMO
Background: Idiopathic pulmonary fibrosis (IPF) is a heterogeneous and progressive fibrosing interstitial lung disease with a poor prognosis. However, there are currently no effective biomarker that can reliably predict the prognosis for IPF in clinic. The serum level of soluble suppression of tumorigenicity-2 (sST2), which is involved in the immune response, has proven to be a prognostic predictor for various diseases. Previous studies have confirmed that the immune dysfunction plays an important role in the pathogenesis of IPF and the serum sST2 concentrations in patients with IPF are elevated. However, the relationship between sST2 and the prognosis of IPF remains unknown. Methods: A total of 83 patients with IPF and 20 healthy controls from 2016 to 2021 were enrolled and demographic variables, indices of lung function testing as well as the biomarkers including the sST2 were obtained at baseline. During follow-up, the primary endpoint was defined as all-cause death and clinical deterioration. Cox hazard models and Kaplan-Meier method were used to assess the prognostic value of various indices including sST2. Results: Mean duration of follow-up was 29 months, during which 49 patients had an event, and of them, 35 patients died. The sST2 level was higher in the IPF patients compared with the healthy controls. Although the sST2 level did not directly predict all-cause death in the present study, it was proved to be an independent predictor of event-free survival. Multivariate forward stepwise model which was adjusted by age, sex, and body surface area (BSA) showed that the overexpression of sST2 increased the hazard ratio [1.005, 95% confidence interval (CI): 1.001-1.010]. A higher sST2 serum level heralded more deterioration and the poor outcomes. Moreover, the effect of sST2 on the prognosis of IPF may not necessarily involve the development of IPF-related pulmonary hypertension (PH). Conclusions: In our study, the sST2 serum level was significantly elevated and a higher serum level of sST2 predicted more deterioration and poor outcomes in patients with IPF. Thus, sST2 can serve as a valuable prognostic biomarker for the outcome of IPF. However, further multicenter clinical trials of larger sample size are needed in the future.
RESUMO
BACKGROUND: Aberrant activation of epidermal growth factor receptor (EGFR) signaling pathway is associated with the pathogenesis of pulmonary hypertension (PH). However, the effect of icotinib, a first generation of EGFR tyrosine kinase inhibitor (EGFR-TKI), on PH remains to be elucidated. METHODS: PH rat model was established by a single intraperitoneal injection of monocrotaline (MCT, 60 mg/kg). Icotinib (15, 30, and 60 mg/kg/day) was administered by oral gavage from the day of MCT injection. After 4 weeks, hemodynamic parameters and histological changes of the pulmonary arterial vessels were assessed, and the phenotypic switching of pulmonary arterial smooth muscle cells (PASMCs) was determined in vivo. Moreover, the effects of icotinib (10 µM) on epidermal growth factor (EGF, 50 ng/ml)-stimulated proliferation, migration, and phenotypic switching of human PASMCs were explored in vitro. RESULTS: Icotinib significantly reduced the right ventricular systolic pressure and right ventricle hypertrophy index in rats with MCT-induced PH. Moreover, icotinib improved MCT-induced pulmonary vascular remodeling. The expression of contractile marker (smooth muscle 22 alpha (SM22α)) and synthetic markers (osteopontin (OPN) and vimentin) in pulmonary artery was restored by icotinib treatment. In vitro, icotinib suppressed EGF-induced PASMCs proliferation and migration. Meanwhile, icotinib inhibited EGF-induced downregulation of α-smooth muscle actin and SM22α and upregulation of OPN and Collagen I in PASMCs, suggesting that icotinib could inhibit EGF-induced phenotypic switching of PASMCs. Mechanistically, these effects of icotinib were associated with the inhibition of EGFR-Akt/ERK signaling pathway. CONCLUSIONS: Icotinib can attenuate MCT-induced pulmonary vascular remodeling and improve PH. This effect of icotinib might be attributed to preventing PASMC dysfunction by inhibiting EGFR-Akt/ERK signaling pathway.