Pirfenidone suppresses bleomycin-induced pulmonary fibrosis and periostin expression in rats

Cinnamic acid mitigates methotrexate-induced lung fibrosis in rats: comparative study with pirfenidone

PURPOSE

Lung fibrosis is a heterogeneous lung condition characterized by excessive accumulation of scarred tissue, leading to lung architecture destruction and restricted ventilation. The current work was conducted to examine the probable shielding influence of cinnamic acid against lung fibrosis induced by methotrexate.

METHODS

Rats were pre-treated with oral administration of cinnamic acid (50 mg/kg/day) for 14 days, whereas methotrexate (14 mg/kg) was orally given on the 5th and 12th days of the experiment. Pirfenidone (50 mg/kg/day) was used as a standard drug. At the end of the experiment, oxidative parameters (malondialdehyde, myeloperoxidase, nitric oxide, and total glutathione) and inflammatory mediators (tumor necrosis factor-α and interleukin-8), as well as transforming growth factor-β and collagen content, as fibrosis indicators, were measured in lung tissue.

RESULTS

Our results revealed that cinnamic acid, as pirfenidone, effectively prevented the methotrexate-induced overt histopathological damage. This was associated with parallel improvements in oxidative, inflammatory, and fibrotic parameters measured. The outcomes of cinnamic acid administration were more or less the same as those of pirfenidone. In conclusion, pre-treatment with cinnamic acid protects against methotrexate-induced fibrosis, making it a promising prophylactic adjuvant therapy to methotrexate and protecting against its possible induction of lung fibrosis.

Protective efficacy of pirfenidone in rats with pulmonary fibrosis induced by bleomycin

BACKGROUND

Bleomycin causes increased production of reactive oxygen species, leads to pulmonary toxicity, fibroblast activation, and fibrosis.

OBJECTIVES

This study aimed to evaluate the protective effect of pirfenidone on bleomycin-induced lung toxicity in rats.

METHODS

Twenty-eight adult rats were randomly divided into 3 groups; Bleomycin (B group, n=10), Bleomycin and Pirfenidone (B-PND group, n=13), and the control group (n=5). The bleomycin regimen was administered for 9 weeks. Pirfenidone was administered at 100 mg/kg daily. Total antioxidant level (TAS), total oxidant level (TOS), tumor necrosis factor (TNF-α), transforming growth factor (TGF-β1), matrix metalloproteinase-2 (MMP-2), plasminogen activator inhibitor (PAI) levels were studied. Histopathologically, sections were stained with Hematoxylin-eosin and Masson-trichrome for grading-scoring according to the Ashcroft score.

RESULTS

Stage 3 fibrosis was observed in 50% of the B group rats, stage 3 and higher fibrosis was never detected in the B-PND group and the difference was statistically significant (p=0.003). When evaluating tissue inflammation, the inflammation was higher in the B-PND group than in the other groups (p<0.001). Pleuritis was detected in all rats in group B, while was not observed in B-PND and control group (p<0.001). The TAS level was found to be significantly higher in group B than in group B-PND (p=0.034), while no difference was found between TOS, TNF-α, MMP-2, PAI, TGF-β1.

CONCLUSIONS

Pirfenidone had a statistically significant protective effect in bleomycin-induced lung fibrosis and pleuritis in rats.  Despite the presence of inflammation in the tissue, no significant changes were observed in inflammation markers in the peripheral blood. Novel serum biomarkers are needed to indicate the presence of inflammation and fibrosis in the lung.

Epithelial Alarmins in Serum and Exhaled Breath in Patients with Idiopathic Pulmonary Fibrosis: A Prospective One-Year Follow-Up Cohort Study

Background: Recently, epithelial alarmins have been shown to play important roles in non-allergen driven respiratory diseases like idiopathic pulmonary fibrosis (IPF). Little is known about the expression of the epithelial alarmins in IPF. Methods: This study aimed to prospectively examine interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP) levels in the serum and exhaled breath condensate (EBC) in patients with IPF before and after one-year of antifibrotic treatment. A total of 82 volunteers, including 52 patients diagnosed with IPF that qualified for antifibrotic therapy as well as 30 controls, were examined. All study participants underwent baseline peripheral blood and EBC sampling. In 35 out of 52 IPF subjects, a follow-up sampling was performed after 12 months of antifibrotic treatment. Concentrations of alarmins in the serum and EBC were evaluated by means of ELISA. Results: Baseline TSLP concentrations were significantly elevated in patients with IPF compared to controls both in the serum (p < 0.05) and EBC (p < 0.0001). Baseline IL-25 and IL-33 serum and EBC levels did not differ significantly between IPF subjects and controls. Prospective analysis of changes in the epithelial alarmin levels showed significantly decreased IL-25 and TSLP EBC concentrations after 12 months of antifibrotic treatment (p < 0.05), which was observed in the subgroup of IPF patients treated with pirfenidone, but not in those treated with nintedanib. In stable patients with IPF over a study period (absolute forced vital capacity (FVC) % of predicted decline/year ≤ 5%, n = 25), a significant decrease in the EBC levels of both IL-25 and TSLP after 12 months of antifibrotic treatment was noted (p < 0.05), whereas, in progressor IPF patients (absolute FVC % of predicted decline/year > 5%, n = 10), a significant decrease was noted in the IL-25 EBC levels only (p < 0.05). Conclusions: Elevated TSLP levels in patients with IPF and their significant decrease in the lung compartment during antifibrotic therapy in stable patients with IPF, but not in progressors, support its significant contribution to pro-fibrotic type 2 immune responses in IPF. Noted changes in the epithelial alarmins concentration in the lung compartment during pirfenidone therapy may suggest its possible interaction with epithelial alarmins pathways in IPF.

Absence of early metabolic response assessed by 18F-FDG PET/CT after initiation of antifibrotic drugs in IPF patients

Background

Idiopathic pulmonary fibrosis (IPF) is characterized by a progressive and irreversible respiratory failure. Non-invasive markers of disease activity are essential for prognosis and evaluation of early response to anti-fibrotic treatments.

Objectives

The aims of this study were to determine whether fluorodeoxyglucose ([18F]-FDG) lung uptake is reduced after initiation of pirfenidone or nintedanib and to assess its possible use as a prognostic factor.

Methods

[18F]-FDG PET/CT was performed in IPF patients and in a murine model of pulmonary fibrosis. PET/CTs were performed at day 8 and day 15 post-instillation of bleomycin in pirfenidone- or vehicule-treated mice. In IPF patients, PET-CT was performed before and 3 months after the initiation of pirfenidone or nintedanib.

Results

In bleomycin-treated mice, pirfenidone significantly reduced the [18F]-FDG uptake compared to vehicule-treated mice at day 15 (p < 0.001), whereas no difference was observed at day 8 after bleomycin administration. In IPF patients, [18F]-FDG lung uptake before and after 3 months of treatment by nintedanib (n = 11) or pirfenidone (n = 14) showed no significant difference regardless the antifibrotic treatment. Moreover, no difference was noticed between patients with progressive or non-progressive disease at one year of follow up.

Conclusions

Pirfenidone significantly reduces the lung [18F]-FDG uptake during the fibrotic phase in a mouse model of IPF. However, these preclinical data were not confirmed in IPF patients 3 months after the initiation of antifibrotic therapy. [18F]-FDG seems therefore not useful in clinical practice to assess the early response of IPF patients to nintedanib or pirfenidone.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-0974-5) contains supplementary material, which is available to authorized users.