Effects of antifibrotic agents on TGF-β1, CTGF and IFN-γ expression in patients with idiopathic pulmonary fibrosis

SummaryIdiopathic pulmonary fibrosis (IPF) is a deadly disease, largely unresponsive to treatment with corticosteroids and immunosuppressives. The aim of this randomized, prospective, open-label study was to characterize the molecular effects of IFN-γ-1b and colchicine, on biomarkers expression associated with fibrosis (TGF-β, CTGF) and immunomodulatory/antimicrobial activity (IFN-γ), in the lungs of patients with IPF.Fourteen (14) patients with an established diagnosis of IPF received either 200 μg of IFN-γ-1b subcutaneously three times per week, or 1 mg of oral colchicine per day, for 24 months. Using RT-PCR assay, we evaluated the transcription levels of transforming growth factor β1 (TGF-β1), connective-tissue growth factor (CTGF), and interferon-γ (IFN-γ) genes in lung tissue before and after treatment with IFN-γ-1b or colchicine.Marked mRNA expression of TGF-β1 and CTGF, but complete lack of interferon-γ was detected in fibrotic lung tissue at entry. After treatment, both groups exhibited increased expression of IFN-γ gene at 6 months that was sustained at 24 months. The expression of CTGF and TGF-β1 remained almost stable before and after treatment, in the IFN-γ-1b group, while TGF-β1 was statistically decreased after therapy, in the colchicine group (p=0.0002). Significant difference in DLCO (% pred), was found between the two treatment groups in favor of IFN-γ-1b group (p=0.04). In addition, the IFN-γ-1b group showed stability in arterial PO2 while the colchicine group significantly deteriorated (p=0.02).In conclusion, we report the effect of antifibrotic agents (IFN-γ-1b and colchicine) in TGF-β, CTGF, and endogenous IFN-γ gene expression, in human fibrosis. However, extended studies are needed to verify the pathophysiological consequences of these findings.