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Effect of endothelin inhibition on lung fibroblasts on patients with systemic sclerosis
A Corrado1, A Neve, E Costantino
1Rheumatology Clinic Department of Medical and Surgical Sciences University of Foggia, Foggia, Italy - fp.cantatore@unifg.it.
Aim:
The aim of the study was to investigate the effect of selective ETRA Sitaxsentan on viability and differentiation into myofibroblasts of lung fibroblasts derived from SSc-ILD patients and the ability of this drug to modify the lung fibroblast synthesis of VEGF, type I collagen and fibronectin.
Methods:
Primary human lung fibroblast cultures were obtained from BAL of SSc-ILD patients. Cell cultures were exposed for 48 h to crescent concentrations of Sitaxsentan (10 -6M to 10 -4M). In these experimental conditions we evaluated cell viability through crystal violet staining, the production and mRNA expression of VEGF, fibronectin and type I collagen respectively through ELISA and real-Time PCR. Further, we detected alpha-Smooth Muscle Actin (α-SMA) through immunocytochemical assay.
Results:
The lowest concentration of sitaxsentan (10-6M) did not affect fibroblasts viability; conversely at higher concentrations, sitaxsentan induced a significant inhibition of cell viability. Synthesis and mRNA expression of VEGF, type 1 collagen and fibronectin were significantly reduced in treated lung fibroblasts compared to the untreated ones, in a dose-dependent manner. At higher concentrations, Sitaxsentan reduced the expression of α-SMA.
Conclusion:
The results of this study show that sitaxentan is able in vitro to reduce both cell viability than production of VEGF and extra-cellular matrix components in SSc lung fibroblasts, confirming the anti-fibrotic potential of ETRA in SSc. The decreased expression of α-SMA in treated cells indicate that sitaxsentan may inhibit the fibroblast differentiation toward a myo-fibroblast phenotype and further support the hypothesis that the selective ETRAs may be beneficial in patients with SSc-ILD as anti fibrotic agents.
Insights
Sitaxsentan, an endothelin receptor antagonist (ETRA), reduced lung fibroblast viability and extracellular matrix production in Scleroderma-associated Interstitial Lung Disease (SSc-ILD) models. This suggests ETRAs may be effective anti-fibrotic agents for SSc-ILD.
Area of Science:
- Pulmonary Medicine
- Fibrosis Research
- Pharmacology
Background:
- Scleroderma-associated interstitial lung disease (SSc-ILD) is characterized by progressive lung fibrosis.
- Lung fibroblasts play a key role in the pathogenesis of SSc-ILD by synthesizing extracellular matrix components.
- Selective endothelin receptor antagonists (ETRAs) have shown potential in treating fibrotic conditions.
Purpose of the Study:
- To investigate the in vitro effects of the selective ETRA, Sitaxsentan, on lung fibroblasts from SSc-ILD patients.
- To assess Sitaxsentan's impact on fibroblast viability, differentiation into myofibroblasts, and synthesis of key fibrotic markers.
Main Methods:
- Primary human lung fibroblasts from SSc-ILD patients were cultured and treated with varying concentrations of Sitaxsentan.
- Cell viability was assessed using crystal violet staining.
- Production and mRNA expression of VEGF, type I collagen, and fibronectin were quantified using ELISA and real-time PCR.
- Alpha-smooth muscle actin (α-SMA) expression, a marker of myofibroblast differentiation, was evaluated via immunocytochemistry.
Main Results:
- Sitaxsentan inhibited lung fibroblast viability at higher concentrations in a dose-dependent manner.
- Treatment with Sitaxsentan significantly reduced the synthesis and mRNA expression of VEGF, type I collagen, and fibronectin.
- Sitaxsentan decreased α-SMA expression at higher concentrations, indicating inhibition of myofibroblast differentiation.
Conclusions:
- Sitaxsentan demonstrates in vitro anti-fibrotic potential by reducing lung fibroblast viability and extracellular matrix component production in SSc-ILD models.
- The drug's ability to decrease α-SMA expression suggests it may inhibit fibroblast differentiation into myofibroblasts.
- These findings support the potential therapeutic benefit of selective ETRAs as anti-fibrotic agents for SSc-ILD patients.
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