Idiopathic pulmonary fibrosis: lessons from clinical trials over the past 25 years

Kindlin-2 Acts as a Key Mediator of Lung Fibroblast Activation and Pulmonary Fibrosis Progression

Pulmonary fibrosis is a progressive and fatal lung disease characterized by activation of lung fibroblasts and excessive deposition of collagen matrix. We show here that the concentrations of kindlin-2 and its binding partner PYCR1, a key enzyme for proline synthesis, are significantly increased in the lung tissues of human patients with pulmonary fibrosis. Treatment of human lung fibroblasts with TGF-β1 markedly increased the expression of kindlin-2 and PYCR1, resulting in increased kindlin-2 mitochondrial translocation, formation of the kindlin-2-PYCR1 complex, and proline synthesis. The concentrations of the kindlin-2-PYCR1 complex and proline synthesis were markedly reduced in response to pirfenidone or nintedanib, two clinically approved therapeutic drugs for pulmonary fibrosis. Furthermore, depletion of kindlin-2 alone was sufficient to suppress TGF-β1-induced increases of PYCR1 expression, proline synthesis, and fibroblast activation. Finally, using a bleomycin mouse model of pulmonary fibrosis, we show that ablation of kindlin-2 effectively reduced the concentrations of PYCR1, proline, and collagen matrix and alleviate the progression of pulmonary fibrosis in vivo. Our results suggest that kindlin-2 is a key promoter of lung fibroblast activation, collagen matrix synthesis, and pulmonary fibrosis, underscoring the therapeutic potential of targeting the kindlin-2 signaling pathway for control of this deadly lung disease.

Iron deposition-induced ferroptosis in alveolar type II cells promotes the development of pulmonary fibrosis

Ferroptosis is a newly discovered type of regulated cell death, characterized by the iron-dependent accumulation of lipid reactive oxygen species, which has been implicated in numerous human diseases. However, its role in pulmonary fibrosis, a fatal lung disease with unknown etiology, is largely unknown. Here, we investigated the role of ferroptosis in pulmonary fibrosis. We found a large amount of iron deposition in the lung tissue of patients with pulmonary fibrosis. We observed ferroptosis in alveolar type II (ATII) cells, fibrotic lung tissues of BLM-induced pulmonary fibrosis mice. BLM-induced increase in iron level was accompanied by pathological changes, collagen deposition, and ferroptosis in ATII cells, indicating iron deposition-induced ferroptosis, which promoted the development of pulmonary fibrosis. Moreover, deferoxamine (DFO) completely prevented the pro-fibrosis effects of BLM by reducing iron deposition and ferroptosis in ATII cells. Genes associated with intracellular iron metabolism and homeostasis, such as transferrin receptor 1, divalent metal transporter 1, and ferroportin-1, and showed abnormal expression levels in animal tissues and lung epithelial MLE-12 cells, which responded to BLM stimulation. Overall, we demonstrated that BLM-induced iron deposition in MLE-12 cells is prone to both mitochondrial dysfunction and ferroptosis and that DFO reverses this phenotype. In the future, understanding the role of ferroptosis may shed new light on the etiology of pulmonary fibrosis. Ferroptosis inhibitors or genetic engineering of ferroptosis-related genes might offer potential targets to treat pulmonary fibrosis.

Rheumatological evaluation of patients with interstitial lung disease

Objective: Interstitial lung disease (ILD) is a common feature of connective tissue disease (CTD). The diagnosis of CTD-ILD can be challenging and is important for therapeutic decisions. In this study, we aimed to determine whether a systematic rheumatological assessment could help pulmonologists in the diagnosis and care of ILD patients.Method: We conducted an observational single-centre study of patients with ILD. All patients underwent standardized pulmonary and rheumatological evaluations, including clinical evaluation (pulmonary symptoms and musculoskeletal signs), immunological screening, chest high-resolution computed tomography, pulmonary function tests, and ultrasonography (US) of joints and major salivary glands.Results: We included 100 consecutive ILD patients (47% women, mean ± sd age 67 ± 14 years); 15 patients already had CTD. The main extrapulmonary symptoms were joint pain (n = 52), joint swelling (n = 26), and sicca syndrome (n = 33). US of joints revealed synovitis, bone erosion, and tenosynovitis in 37, 17, and 13 patients, respectively. US of major salivary glands detected features associated with Sjögren's syndrome in 13 patients. After rheumatological evaluation, CTD-ILD was confidently diagnosed in 39 patients; diseases were mainly rheumatoid arthritis (n = 20), primary Sjögren's syndrome (n = 17), and inflammatory myopathies (n = 7). The diagnosis of CTD-ILD was associated with the presence of musculoskeletal symptoms and immunological and US abnormalities. The CTD diagnosis led to a therapeutic change in 21 patients.Conclusion: Our findings suggest that musculoskeletal symptoms are frequent in ILD patients, which supports multidisciplinary management, involving the rheumatologist, for evaluating patients with ILD.

Current and future treatment for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fibrosing interstitial lung disease, which is associated with a short survival rate. The decline in forced vital capacity in patients with IPF appears to be almost the same rate regardless of baseline lung function status. This suggests that early treatment would be necessary to prevent further deterioration even lung function is maintained within normal limits. Both pirfenidone and nintedanib significantly slow the decline in lung function, reduce the risk of acute exacerbation, and improve survival rate. However, many individuals with IPF remain untreated. Most IPF patients can tolerate antifibrotic drug therapy, and the dose adjustment has been shown to effectively reduce side effects without modifying efficacy. Although the recent introduction of pirfenidone and nintedanib has led to the slowing of lung function decline, there is no evidence of fibrosis reversal. In the near future, several new drugs are expected to be prescribed to patients with IPF. We are anticipating that some drugs may reverse fibrosis. Fibrosis inhibiting drugs have different pharmacological actions and there are various mechanisms causing fibrosis in the lesion. Therefore, it is imperative to launch efforts to optimize antifibrotic effects through a combination therapy of several drugs. These efforts will hold out hope for patients with IPF.

Metabolic reprogramming: A driver of cigarette smoke-induced inflammatory lung diseases

Cigarette smoking is a well-known risk factor for pulmonary diseases, including chronic obstructive pulmonary disease (COPD), asthma and pulmonary fibrosis. Despite major progress in dissecting the mechanisms associated with disease development and progression, findings only represent one aspect of multifaceted disease. A crucial consequence of this approach is that many therapeutic treatments often fail to improve or reverse the disease state as other conditions and variables are insufficiently considered. To expand our understanding of pulmonary diseases, omics approaches, particularly metabolomics, has been emerging in the field. This strategy has been applied to identify putative biomarkers and novel mechanistic insights. In this review, we discuss metabolic profiles of patients with COPD, asthma, and idiopathic pulmonary fibrosis (IPF) with a focus on the direct effects of cigarette smoking in altering metabolic regulation. We next present cell- and animal-based experiments and point out the therapeutic potential of targeting metabolic reprogramming in inflammatory lung diseases. In addition, the obstacles in translating these findings into clinical practice, including potential adverse effects and limited pharmacological efficacy, are also addressed.

Supportive care of patients with fibrosing interstitial lung disease: answering a great clinical need

The fibrosing interstitial lung diseases (F-ILDs) are a heterogeneous group, including idiopathic pulmonary fibrosis (IPF), connective tissue disease-associated interstitial lung disease, hypersensitivity pneumonitis and asbestosis, among others. The common feature of all F-ILDs is the irreversible replacement of normal lung parenchyma with scar tissue, resulting in impaired gas exchange and culminating in respiratory failure.

Fibrosing interstitial lung disease (F-ILD) significantly reduces quality of life. F-ILD care includes symptom management, end-of-life planning and supportive measures, as well as antifibrotics. Patients and carers should be central to all care decisions.https://bit.ly/2ZAE2Ks

Fibroblasts and their responses to chronic injury in pulmonary fibrosis

The field of pulmonary fibrosis is rapidly expanding as new insights highlight novel mechanisms that influence fibroblast biology and likely promote aberrant and chronic activation of the tissue repair response. Current paradigms suggest repeated epithelial microinjury as a driver for pathology; however, the rapid expansion of pulmonary fibrosis research calls for an overview on how fibroblasts respond to both neighbouring cells and the injury microenvironment. This review seeks to highlight recent discoveries and identify areas that require further research regarding fibroblasts, and their role in pulmonary fibrosis.

Beneficial impact of weight loss on respiratory function in interstitial lung disease patients with obesity

BACKGROUND

Interstitial lung disease (ILD) patients commonly become obese or overweight due to deteriorated daily living activities and the adverse effects of prednisolone. This study aimed to clarify the effect of weight loss on pulmonary function test (PFT) in ILD patients with obesity.

METHODS

Among all consecutive ILD patients with a body mass index (BMI) ≥ 27 kg/m² who received nutrition education for improving obesity between June 2014 and December 2018, we retrospectively included patients who successfully decreased their body weight by over 2 kg and underwent follow-up PFT within 6 months. The results of PFT at baseline and follow-up and the level of Krebs von den Lungen-6 (KL-6) were compared.

RESULTS

Eleven patients (5 men and 6 women; median BMI of 34.1 kg/m²), were enrolled. For PFT at baseline, the percentages of forced vital capacity (%FVC), functional residual capacity (%FRC), and diffusing capacity of the lung for carbon monoxide (%DLCO) were 69.3%, 59.9%, and 54%, respectively. The median KL-6 was 1035 U/mL. The median interval from baseline to the follow-up PFTs was 41 days. Compared to the baseline results of PFT, %FVC, %FRC, and %DLCO significantly increased (p = 0.018, 0.0006, and 0.024, respectively), and the changes in body weight and FVC were strongly correlated (p = 0.0004). In addition, the median serum level of KL-6 at follow-up tended to decrease by 206.5 U/mL (p = 0.083).

CONCLUSION

In ILD patients with obesity, weight loss is important and potentially improves their disease course.

Health-related quality of life of patients with idiopathic pulmonary fibrosis: a systematic review and meta-analysis

Idiopathic pulmonary fibrosis (IPF) is one of the most common forms of interstitial lung disease presenting in persons 50 years and older. Through a comprehensive review of available studies, we aimed to assess health-related quality of life (HRQoL) of people living with IPF and the instruments used in this assessment.Searches were conducted up to May, 2020. Quality appraisal and data extraction were performed using pre-designed forms. Narrative synthesis approach was used to report results of the systematic review and a random effects model was used for the meta-analysis. A leave-one-out sensitivity analysis was performed, and a trim and fill method was used to assess publication bias.The review included 134 studies. The most used instruments to measure HRQoL were St George's Respiratory Questionnaire (SGRQ), Short Form 36 (SF36) and EuroQoL (EQ5D). Standardised mean scores (95% confidence interval) for these instruments were as follows: SGRQ total score: 44.72 (42.21-47.22); SF36 physical component score (PCS): 37.00 (34.74-39.26) SF36 mental component score (MCS): 50.18 (48.41-51.95); King's Brief Interstitial Lung Disease questionnaire total score: 58.38 (55.26-61.51); and EQ5D utility: 0.73 (0.68-0.79). Analysis of standardised means for both SGRQ and SF36 demonstrated worse scores in physical health domains as compared to mental health domains.This systematic review confirms that IPF negatively affected HRQoL, mostly impacting the physical health domains. This study also demonstrated that a diverse number of instruments are used to evaluate HRQoL. In view of this diversity, a standardised approach to measurement of HRQoL for IPF is important to ensure that comparisons made are reliable.

Pulmonary fibrosis alters gut microbiota and associated metabolites in mice: An integrated 16S and metabolomics analysis

AIMS

The "gut-lung axis" reflects intimate connection and bidirectional effect between gut and lung, involving numerous lung diseases. Pulmonary fibrosis is a progressive interstitial lung disease with high fatality rate, so far, its association with gut remains unexplored. We investigated the correlation between pulmonary fibrosis and gut microbiota.

MATERIALS AND METHODS

We collected feces from two pulmonary fibrotic models respectively, and performed a combinatory study using 16S rDNA sequencing and non-targeted metabonomics. Correlation matrix was used to indicate the correlation between microbiome, metabolites and fibrotic indicators, and the possibility of gut microbiota in identifying pulmonary fibrosis was assessed by ROC analysis.

KEY FINDINGS

412 genera of microflora and 26 kinds of metabolites were synchronously altered with same trend in two models but differed observably with control. Among these, 7 microorganisms and 9 metabolites were the typical representatives, which were correlated significantly and highly correlated with fibrotic indicators shown by correlation matrix. ROC analysis indicated that it was dependable to identify pulmonary fibrosis by using gut microorganisms and metabolites in both models (AUC > 0.85, p < 0.01).

SIGNIFICANCE

In summary, our findings first revealed a previously unknown correlation between gut and pulmonary fibrosis in mouse models, which creates novel insights of the interaction between pulmonary fibrosis and gut microbiota.

Potent and Selective Human Prostaglandin F (FP) Receptor Antagonist (BAY-6672) for the Treatment of Idiopathic Pulmonary Fibrosis (IPF)

Idiopathic pulmonary fibrosis (IPF) is a rare and devastating chronic lung disease of unknown etiology. Despite the approved treatment options nintedanib and pirfenidone, the medical need for a safe and well-tolerated antifibrotic treatment of IPF remains high. The human prostaglandin F receptor (hFP-R) is widely expressed in the lung tissue and constitutes an attractive target for the treatment of fibrotic lung diseases. Herein, we present our research toward novel quinoline-based hFP-R antagonists, including synthesis and detailed structure-activity relationship (SAR). Starting from a high-throughput screening (HTS) hit of our corporate compound library, multiple parameter improvements-including increase of the relative oral bioavailability F_rel from 3 to ≥100%-led to a highly potent and selective hFP-R antagonist with complete oral absorption from suspension. BAY-6672 (46) represents-to the best of our knowledge-the first reported FP-R antagonist to demonstrate in vivo efficacy in a preclinical animal model of lung fibrosis, thus paving the way for a new treatment option in IPF.

Australasian interstitial lung disease registry (AILDR): objectives, design and rationale of a bi-national prospective database

Background

Interstitial Lung Disease (ILD) is a group of respiratory conditions affecting the lung interstitium often associated with progressive respiratory failure. There is increasing recognition of the need for improved epidemiological data to help determine best practice and improve standardisation of care. The Australasian ILD Registry (AILDR) is a bi-national registry of patients with all ILD subtypes designed to establish a clinically meaningful database reflecting real world practice in Australasia with an objective to improve diagnostic and treatment pathways through research and collaboration.

Methods

AILDR is a prospective observational registry recruiting patients attending ILD clinics at centres around Australia and New Zealand. Core and non-core data are stored on a secure server. The pilot phase was launched in 2016 consisting of four sites in Australia. Currently in its second phase a further 16 sites have been recruited, including three in New Zealand.

Results

A total of 1061 participants were consented during the pilot phase. Baseline data demonstrated a mean age 68.3 ± 12.5 (SD) years, mean FVC (%predicted) 79.1 ± 20.4 (SD), mean DLCO (%predicted) 58.5 ± 17.9 (SD) and nadir exertional SpO2 (%) 91 ± 6.9 (SD). Idiopathic pulmonary fibrosis (31%) and connective-tissue disease related ILD (21.7%) were the two most common subtypes. Baseline demographics and physiology were not significantly different across the four centres.

Conclusion

AILDR is an important clinical and research tool providing a platform for epidemiological data that will prove essential in promoting understanding of a rare cohort of lung disease and provide foundations for our aspiration to standardise investigation and treatment pathways of ILD across Australasia.

Inhibition of Aurora Kinase B attenuates fibroblast activation and pulmonary fibrosis

Fibroblast activation including proliferation, survival, and ECM production is central to initiation and maintenance of fibrotic lesions in idiopathic pulmonary fibrosis (IPF). However, druggable molecules that target fibroblast activation remain limited. In this study, we show that multiple pro‐fibrotic growth factors, including TGFα, CTGF, and IGF1, increase aurora kinase B (AURKB) expression and activity in fibroblasts. Mechanistically, we demonstrate that Wilms tumor 1 (WT1) is a key transcription factor that mediates TGFα‐driven AURKB upregulation in fibroblasts. Importantly, we found that inhibition of AURKB expression or activity is sufficient to attenuate fibroblast activation. We show that fibrosis induced by TGFα is highly dependent on AURKB expression and treating TGFα mice with barasertib, an AURKB inhibitor, reverses fibroblast activation, and pulmonary fibrosis. Barasertib similarly attenuated fibrosis in the bleomycin model of pulmonary fibrosis. Together, our preclinical studies provide important proof‐of‐concept that demonstrate barasertib as a possible intervention therapy for IPF.

Therapeutic potential of targeting kinase inhibition in patients with idiopathic pulmonary fibrosis

Fibrosis is characterized by excessive accumulation of extracellular matrix components. The fibrotic process ultimately leads to organ dysfunction and failure in chronic inflammatory and metabolic diseases such as pulmonary fibrosis, advanced kidney disease, and liver cirrhosis. Idiopathic pulmonary fibrosis (IPF) is a common form of progressive and chronic interstitial lung disease of unknown etiology. Pathophysiologically, the parenchyma of the lung alveoli, interstitium, and capillary endothelium becomes scarred and stiff, which makes breathing difficult because the lungs have to work harder to transfer oxygen and carbon dioxide between the alveolar space and bloodstream. The transforming growth factor beta (TGF-β) signaling pathway plays an important role in the pathogenesis of pulmonary fibrosis and scarring of the lung tissue. Recent clinical trials focused on the development of pharmacological agents that either directly or indirectly target kinases for the treatment of IPF. Therefore, to develop therapeutic targets for pulmonary fibrosis, it is essential to understand the key factors involved in the pathogenesis of pulmonary fibrosis and the underlying signaling pathway. The objective of this review is to discuss the role of kinase signaling cascades in the regulation of either TGF-β-dependent or other signaling pathways, including Rho-associated coiled-coil kinase, c-jun N-terminal kinase, extracellular signal-regulated kinase 5, and p90 ribosomal S6 kinase pathways, and potential therapeutic targets in IPF.

Pirfenidone: Molecular Mechanisms and Potential Clinical Applications in Lung Disease

Pirfenidone (PFD) is a pharmacological compound with therapeutic efficacy in idiopathic pulmonary fibrosis. It has been chiefly characterized as an antifibrotic agent, although it was initially developed as an antiinflammatory compound because of its ability to diminish the accumulation of inflammatory cells and cytokines. Despite recent studies that have elucidated key mechanisms, the precise molecular activities of PFD remain incompletely understood. PFD modulates fibrogenic growth factors, thereby attenuating fibroblast proliferation, myofibroblast differentiation, collagen and fibronectin synthesis, and deposition of extracellular matrix. This effect is mediated by suppression of TGF-β1 (transforming growth factor-β1) and other growth factors. Here, we appraise the impact of PFD on TGF-β1 production and its downstream pathways. Accumulating evidence indicates that PFD also downregulates inflammatory pathways and therefore has considerable potential as a viable and innovative antiinflammatory compound. We examine the effects of PFD on inflammatory cells and the production of pro- and antiinflammatory cytokines in the lung. In this context, recent evidence that PFD can target inflammasome pathways and ensuing lung inflammation is highlighted. Finally, the antioxidant properties of PFD, such as its ability to inhibit redox reactions and regulate oxidative stress-related genes and enzymes, are detailed. In summary, this narrative review examines molecular mechanisms underpinning PFD and its recognized benefits in lung fibrosis. We highlight preclinical data that demonstrate the potential of PFD as a nonsteroidal antiinflammatory agent and outline areas for future research.

Salvianolic acid B and sodium tanshinone II A sulfonate prevent pulmonary fibrosis through anti-inflammatory and anti-fibrotic process

Pulmonary fibrosis (PF) is an interstitial lung disease characterized by interstitial inflammation and fibrosis. Salvianolic acid B (SAB) and sodium tanshinone IIA sulfonate (STS) are representative components in Salvia miltiorrhiza, which have been reported using in the treatment of PF. The aim of the study was to explain the role of inflammation in the process of PF and to investigate the effect of SAB and STS on inflammation and fibrosis in vitro. The results clearly indicated that lipopolysaccharide (LPS)-stimulated inflammatory response could induce fibroblast proliferation and fibroblast to myofibroblast transformation (FMT). Both SAB and STS significantly inhibited LPS-induced inflammation in vitro, including down-regulated the protein expression levels of IL-1β and TNF-α and the mRNA expression levels of IL1B and TNFA. Furthermore, both SAB and STS inhibited TGF-β1-induced the proliferation in MRC-5 cells and the overexpression of α-SMA and COL1α1, both the protein and mRNA levels. In conclusion, these results indicate that the inflammatory response is necessary for the development of PF, and the therapeutic effect of SAB and STS on PF may be related to anti-inflammatory and anti-fibrotic effects.

Transcriptomic profiling reveals disease-specific characteristics of epithelial cells in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is an incurable disease characterized by progressive lung fibrosis ultimately resulting in respiratory failure and death. Recurrent micro-injuries to the alveolar epithelium and aberrant alveolar wound healing with impaired re-epithelialization define the initial steps of the pathogenic trajectory. Failure of timely alveolar epithelial repair triggers hyper-proliferation of mesenchymal cells accompanied by increased deposition of extracellular matrix into the lung interstitium.

Methods

We previously isolated fibrosis-specific mesenchymal stem cell (MSC)-like cells from lung tissue of patients with interstitial lung diseases. These cells produced factors bearing anti-fibrotic potential and changed their morphology from mesenchymal to epithelial upon culture in an epithelial cell (EC)-specific growth medium. Here, we set out to molecularly characterize these MSC-like cell-derived ECs using global gene expression profiling by RNA-sequencing. Moreover, we aimed at characterizing disease-specific differences by comparing the transcriptomes of ECs from IPF and non-IPF sources.

Results

Our results suggest that differentially expressed genes are enriched for factors related to fibrosis, hypoxia, bacterial colonization and metabolism, thus reflecting many of the hallmark characteristics of pulmonary fibrosis. IPF-ECs showed enrichment of both pro- and anti-fibrotic genes, consistent with the notion of adaptive, compensatory regulation.

Conclusions

Our findings support the hypothesis of a functional impairment of IPF-ECs, which could possibly explain the poor clinical outcome of IPF that roughly compares to those of advanced-stage cancers. Our study provides a valuable resource for downstream mechanistic investigation and the quest for novel therapeutic IPF targets.

Overexpression of TIM-3 in Macrophages Aggravates Pathogenesis of Pulmonary Fibrosis in Mice

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disorder and lacks effective treatments because of unclear mechanisms. Aberrant function of alveolar macrophages is directly linked to pulmonary fibrosis. Here, we show TIM-3 (T-cell immunoglobulin domain and mucin domain-3), a key regulator of macrophage function, aggravates pulmonary fibrosis. TIM-3 mRNA of patients with IPF was analyzed based on the Gene Expression Omnibus and Array Express databases. Lung pathology and profibrotic molecules were assessed in a bleomycin (BLM)-induced pulmonary fibrosis model using wild-type (WT) and TIM-3 transgenic (TIM-3-TG) mice. Macrophage cells, RAW264.7, were then applied to investigate the effect of macrophage TIM-3 under BLM exposure in vitro. Macrophage depletion and adoptive-transfer experiments were finally performed to examine lung morphology and profibrotic molecules. TIM-3 expression was increased both in patients with IPF and in our BLM-induced mouse model. TIM-3-TG mice developed more serious pathological changes in lung tissue and higher expressions of TGF-β1 (transforming growth factor-β1) and IL-10 than WT mice. After BLM treatment, TGF-β1 and IL-10 expression was significantly decreased in RAW264.7 cells after TIM-3 knock-out, whereas it was increased in TIM-3-TG peritoneal macrophages. The scores of pulmonary fibrosis in WT and TIM-3-TG mice were significantly reduced, and there was no difference between them after macrophage depletion. Furthermore, WT mice receiving adoptive macrophages from TIM-3-TG mice also had more serious lung fibrosis and increased expression of TGF-β1 and IL-10 than those receiving macrophages from WT mice. Our findings revealed that overexpressed TIM-3 in alveolar macrophages aggravated pulmonary fibrosis.

Microcystin-LR ameliorates pulmonary fibrosis via modulating CD206+ M2-like macrophage polarization

Idiopathic pulmonary fibrosis (IPF) is a group of chronic interstitial pulmonary diseases characterized by myofibroblast proliferation and extracellular matrix deposition with limited treatment options. Based on our previous observation, we hypothesized microcystin-leucine arginine (LR), an environmental cyanobacterial toxin, could potentially suppress pulmonary fibrosis. In this study, we first demonstrated that chronic exposure of microcystin-LR by oral for weeks indeed attenuated the pulmonary fibrosis both on bleomycin-induced rat and fluorescein isothiocyanate-induced mouse models. Our data further indicated that treatment with microcystin-LR substantially reduced TGF-β1/Smad signaling in rat pulmonary tissues. The experiments in vitro found that microcystin-LR was capable of blocking epithelial–mesenchymal transition (EMT) and fibroblast–myofibroblast transition (FMT) through suppressing the differentiation of CD206⁺ macrophages. Mechanically, microcystin-LR was found to bind to glucose-regulated protein 78 kDa (GRP78) and suppress endoplasmic reticulum unfolded protein response (UPR^ER) signaling pathways. These events led to the modulation of M2 polarization of macrophages, which eventually contributed to the alleviation of pulmonary fibrosis. Our results revealed a novel mechanism that may account for therapeutic effect of microcystin-LR on IPF.

Idiopathic Pulmonary Fibrosis: Best Practice in Monitoring and Managing a Relentless Fibrotic Disease

Idiopathic pulmonary fibrosis (IPF) is a fibrosing interstitial lung disease that is, by definition, progressive. Progression of IPF is reflected by a decline in lung function, worsening of dyspnea and exercise capacity, and deterioration in health-related quality of life. In the short term, the course of disease for an individual patient is impossible to predict. A period of relative stability in forced vital capacity (FVC) does not mean that FVC will remain stable in the near future. Frequent monitoring using multiple assessments, not limited to pulmonary function tests, is important to evaluate disease progression in individual patients and ensure that patients are offered appropriate care. Optimal management of IPF requires a multidimensional approach, including both pharmacological therapy to slow decline in lung function and supportive care to preserve patients' quality of life.

Modeling Progressive Fibrosis with Pluripotent Stem Cells Identifies an Anti-fibrotic Small Molecule

Progressive organ fibrosis accounts for one-third of all deaths worldwide, yet preclinical models that mimic the complex, progressive nature of the disease are lacking, and hence, there are no curative therapies. Progressive fibrosis across organs shares common cellular and molecular pathways involving chronic injury, inflammation, and aberrant repair resulting in deposition of extracellular matrix, organ remodeling, and ultimately organ failure. We describe the generation and characterization of an in vitro progressive fibrosis model that uses cell types derived from induced pluripotent stem cells. Our model produces endogenous activated transforming growth factor β (TGF-β) and contains activated fibroblastic aggregates that progressively increase in size and stiffness with activation of known fibrotic molecular and cellular changes. We used this model as a phenotypic drug discovery platform for modulators of fibrosis. We validated this platform by identifying a compound that promotes resolution of fibrosis in in vivo and ex vivo models of ocular and lung fibrosis.

Protective effects of GHK-Cu in bleomycin-induced pulmonary fibrosis via anti-oxidative stress and anti-inflammation pathways

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a serious lung problem with advancing and diffusive pulmonary fibrosis as the pathologic basis, and with oxidative stress and inflammation as the key pathogenesis. Glycyl-L-histidyl-l-lysine (GHK) is a tripeptide participating into wound healing and regeneration. GHK-Cu complexes improve GHK bioavailability. Thus, the current study aimed to explore the therapeutic role of GHK-Cu on bleomycin (BLM)-induced pulmonary fibrosis in a mouse model.

METHODS

BLM (3 mg/kg) was administered via tracheal instillation (TI) to induce a pulmonary fibrosis model in C57BL/6j mice 21 days after the challenge of BLM. GHK-Cu was injected intraperitoneally (i.p.) at different dosage of 0.2, 2 and 20 μg/g/day in 0.5 ml PBS on alternate day. The histological changes, inflammation response, the collagen deposition and epithelial-mesenchymal transition (EMT) was evaluated in the lung tissue. EMT was evaluated by ɑ-SMA and fibronectin expression in the lung tissue. NF-κB p65, Nrf2 and TGFβ1/Smad2/3 signalling pathways were detected by immunoblotting analysis.

RESULTS

GHK-Cu complex inhibited BLM-induced inflammatory and fibrotic pathological changes, alleviated the inflammatory response in the BALF by reducing the levels of the inflammatory cytokines, TNF-ɑ and IL-6 and the activity of MPO as well as reduced collagen deposition. In addition, the GHK-Cu treatment significantly reversed the MMP-9/TIMP-1 imbalance and partially prevented EMT via Nrf2, NF-κB and TGFβ1 pathways, as well as Smad2/3 phosphorylation.

CONCLUSIONS

GHK-Cu presented a protective effect in BLM-induced inflammation and oxidative stress by inhibiting EMT progression and suppressing TGFβ1/Smad2/3 signalling in pulmonary fibrosis.

Antisynthetase syndrome pathogenesis: knowledge and uncertainties

PURPOSE OF REVIEW

Antisynthetase syndrome (ASyS) is an acquired myopathy characterized by the presence of myositis-specific autoantibodies directed against tRNA-synthetases. ASyS is potentially life threatening due to lung involvement and treatment remains a challenge to date. With symptoms not limited to muscles but also involving lung, skin and joints, ASyS appears specific and has a particular pathogenesis, different from the other inflammatory myopathies. This review is intended to discuss the current understanding of ASyS pathogenesis, pointing its current knowledge and also the crucial prospects that may lead to critical improvement of ASyS care.

RECENT FINDINGS

Regarding ASyS pathogenesis, initiation of the disease seems to arise in a multifactorial context, with first lesions occurring within the lungs. This may lead to aberrant self-antigen exposure and tolerance breakdown. The consequences are abnormal activation of both innate and adaptive immunity, resulting in the patients with favourable genetic background to autoimmune-mediated organ lesions. Immune and nonimmune roles of the antigen, as well as antigen presentation leading to specific T-cell and B-cell activation and to the production of specific autoantibodies belong to the disease process.

SUMMARY

This work aims to detail ASyS pathogenesis understanding, from initiation to the disease propagation and target tissue lesions, in order to considering future treatment directions.

Antifibrotic therapy for fibrotic lung disease beyond idiopathic pulmonary fibrosis

Two antifibrotic medications (nintedanib and pirfenidone) were recommended (conditionally) for the treatment of patients with idiopathic pulmonary fibrosis (IPF) in the 2015 IPF evidence-based guidelines. These medications have been shown to reduce the rate of decline in forced vital capacity among patients with IPF over time and are the only two disease-modulating pharmacological agents approved by regulatory agencies and available for clinical use worldwide. With the evolved standard of care for interstitial lung disease evaluation including routine use of high-resolution computed tomography, fibrotic lung diseases other than IPF are increasingly recognised. In addition, it is becoming evident that genetic and pathophysiological mechanisms as well as disease behaviour in patients manifesting other "non-IPF progressive fibrotic interstitial lung diseases" (non-IPF-PF) may be similar to those in patients with IPF. Thus, it is biologically plausible that pharmacological agents with antifibrotic properties may be efficacious in non-IPF-PF. Indeed, studies are underway or planned to assess the safety and efficacy of nintedanib or pirfenidone among patients with several non-IPF fibrotic lung diseases. In this review, we briefly summarise the use of pirfenidone and nintedanib in IPF as well as the rationale and potential for use of these medications in non-IPF-PF that are being investigated in ongoing and upcoming clinical trials.

The therapy of idiopathic pulmonary fibrosis: what is next?

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease, characterised by progressive scarring of the lung and associated with a high burden of disease and early death. The pathophysiological understanding, clinical diagnostics and therapy of IPF have significantly evolved in recent years. While the recent introduction of the two antifibrotic drugs pirfenidone and nintedanib led to a significant reduction in lung function decline, there is still no cure for IPF; thus, new therapeutic approaches are needed. Currently, several clinical phase I-III trials are focusing on novel therapeutic targets. Furthermore, new approaches in nonpharmacological treatments in palliative care, pulmonary rehabilitation, lung transplantation, management of comorbidities and acute exacerbations aim to improve symptom control and quality of life. Here we summarise new therapeutic attempts and potential future approaches to treat this devastating disease.

Antifibrotic therapy for idiopathic pulmonary fibrosis: time to treat

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with a dismal prognosis. The average life expectancy of untreated patients with IPF is only 3 to 4 years. Decline in forced vital capacity (FVC) in patients with IPF appears to be almost linear, with patients with well-preserved FVC at baseline experiencing the same rate of decline in FVC as patients with more advanced disease. Two antifibrotic therapies have been approved for the treatment of IPF: nintedanib and pirfenidone. These drugs slow decline in lung function and reduce the risk of acute respiratory deteriorations, which are associated with very high morbidity and mortality. Individual clinical trials have not been powered to show reductions in mortality, but analyses of pooled data from clinical trials, as well as observational studies, suggest that antifibrotic therapies improve life expectancy. Despite this, many individuals with IPF remain untreated. In many cases, this is because the physician perceives that the disease is stable and so does not warrant therapy, or has concerns over the potential side-effects of antifibrotic drugs. There remains a need to educate pulmonologists that IPF is a progressive, irreversible and fatal disease and that prompt treatment is critical to preserving patients’ lung function and improving outcomes. Most individuals can tolerate antifibrotic therapy, and dose adjustment has been shown to be effective at reducing side effects without compromising efficacy. In addition to anti-fibrotic therapies, individuals with IPF benefit from a holistic approach to their care that includes symptom management and supportive care tailored to the needs of the individual. An animation illustrating the themes covered in this article will be available at: http://www.usscicomms.com/respiratory/maher/treatment-of-IPF.

Patient Registries in Idiopathic Pulmonary Fibrosis

Over the past decade, several large registries of patients with idiopathic pulmonary fibrosis (IPF) have been established. These registries are collecting a wealth of longitudinal data on thousands of patients with this rare disease. The data collected in these registries will be complementary to data collected in clinical trials because the patient populations studied in registries have a broader spectrum of disease severity and comorbidities and can be followed for a longer period of time. Maintaining the quality and completeness of registry databases presents administrative and resourcing challenges, but it is important to ensuring the robustness of the analyses. Data from patient registries have already helped improve understanding of the clinical characteristics of patients with IPF, the impact that the disease has on their quality of life and survival, and current practices in diagnosis and management. In the future, analyses of biospecimens linked to detailed patient profiles will provide the opportunity to identify biomarkers linked to disease progression, facilitating the development of precision medicine approaches for prognosis and therapy in patients with IPF.

Management of Idiopathic Pulmonary Fibrosis

Objective: Provide information for pharmacists on idiopathic pulmonary fibrosis (IPF) and its treatment. Study Selection and Data Extraction: All articles with data from randomized controlled trials of nintedanib or pirfenidone were reviewed. Data Synthesis: IPF is a progressive and ultimately fatal interstitial lung disease characterized by decline in lung function and worsening dyspnea. It is uncommon and mainly occurs in individuals aged >60 years, particularly men with a history of smoking. Nintedanib and pirfenidone were approved in the United States for the treatment of IPF in 2014 and received conditional recommendations in the 2015 American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Association treatment guidelines. These drugs slow the progression of IPF by reducing the rate of decline in lung function. Their adverse event profile is characterized mainly by gastrointestinal events, which can be managed through dose adjustment and symptom management. Management of IPF should also include smoking cessation, vaccinations, and supportive care such as patient education, pulmonary rehabilitation, and the use of supplemental oxygen as well as optimizing the management of comorbidities. Relevance to Patient Care and Clinical Practice: This review provides clinical pharmacists with information on the course of IPF, what can be expected of current treatments, and how to help patients manage their drug therapy. Conclusions: IPF is a progressive disease, but treatments are available that can slow the progression of the disease. Clinical pharmacists can play an important role in the care of patients with IPF through patient education, monitoring medication compliance and safety, ensuring drugs for comorbidities are optimized, and preventive strategies such as immunizations.

Pulmonary rehabilitation improves survival in patients with idiopathic pulmonary fibrosis undergoing lung transplantation

This study was conducted to evaluate whether a pulmonary rehabilitation program (PRP) is independently associated with survival in patients with idiopathic pulmonary fibrosis (IPF) undergoing lung transplant (LTx). This quasi-experimental study included 89 patients who underwent LTx due to IPF. Thirty-two completed all 36 sessions in a PRP while on the waiting list for LTx (PRP group), and 53 completed fewer than 36 sessions (controls). Survival after LTx was the main outcome; invasive mechanical ventilation (IMV), length of stay (LOS) in intensive care unit (ICU) and in hospital were secondary outcomes. Kaplan-Meier curves and Cox regression models were used in survival analyses. Cox regression models showed that the PRP group had a reduced 54.0% (hazard ratio = 0.464, 95% confidence interval 0.222–0.970, p = 0.041) risk of death. A lower number of patients in the PRP group required IMV for more than 24 hours after LTx (9.0% vs. 41.6% p = 0.001). This group also spent a mean of 5 days less in the ICU (p = 0.004) and 5 days less in hospital (p = 0.046). In conclusion, PRP PRP completion halved the risk of cumulative mortality in patients with IPF undergoing unilateral LTx

Comparison of clinical courses and mortality of connective tissue disease-associated interstitial pneumonias and chronic fibrosing idiopathic interstitial pneumonias

Interstitial lung disease (ILD) is a common pulmonary manifestation of connective tissue diseases (CTD). Prognostic effect of radiological usual interstitial pneumonia (UIP) pattern in CTD-associated interstitial lung disease (CTD-ILD) is unknown. This study aimed to investigate the disease progression and mortality of patients with CTD-ILD and idiopathic interstitial pneumonias (IIP) including idiopathic pulmonary fibrosis (IPF) and idiopathic nonspecific interstitial pneumonia and the prognostic impact of the radiological UIP pattern on both disease groups. The medical records of 91 patients (55 with CTD-ILD and 36 with IIP) diagnosed with ILD at pulmonary medicine department, Faculty of Medicine, Gazi University from 2004 to 2014 were retrospectively reviewed. Patients included whose baseline high-resolution computed tomography (HRCT) scans showed either a UIP or non-UIP pattern. While 67.3% (n = 37) of CTD-ILD patients possessed UIP pattern, 38.9% (n = 14) of IIP patients had UIP pattern in HRCT. Respiratory functions including the forced expiratory volume in the first second (FEV₁ ), functional vital capacity (FVC), and transfer coefficient for carbon monoxide (diffusing capacity of the lung for carbon monoxide [DLCO]) of IIP group at the time of diagnosis were significantly lower than CTD-ILD group (P = .007, P = .002, and P = .019, respectively). There was no significant survival difference between CTD-ILD and IIP by using the log-rank test (P = .76). Multivariate analysis revealed that UIP pattern in HRCT (Hazard ratio: 1.85; 95% Confidence interval = 1.14-3; P = .013), annual FVC (Hazard ratio: 0.521; 95% Confidence interval = 0.32-0.84; P = .007), and annual DLCO declines (Hazard ratio: 0.943; 95% Confidence interval = 0.897-0.991; P = .02) were independent risk factors for mortality in both CTD-ILD and IIP groups. We found that UIP pattern in HRCT and annual losses in respiratory functions were the main determinants of prognosis of ILDs either idiopathic or CTD-associated.

Phase 2 clinical trial of PBI-4050 in patients with idiopathic pulmonary fibrosis

PBI-4050 is a novel orally active small-molecule compound with demonstrated anti-fibrotic activity in several models of fibrosis, including lung fibrosis. We present results from our first clinical study of PBI-4050 in patients with idiopathic pulmonary fibrosis (IPF).

This 12-week open-label study explored the safety, efficacy and pharmacokinetics of daily oral doses of 800 mg PBI-4050 alone and in combination with nintedanib or pirfenidone in patients with predominantly mild or moderate IPF. Nine patients received PBI-4050 alone, 16 patients received PBI-4050 with nintedanib and 16 patients received PBI-4050 with pirfenidone.

PBI-4050 alone or in combination with nintedanib or pirfenidone was well tolerated. Pharmacokinetic profiles for PBI-4050 were similar in the PBI-4050 alone and PBI-4050+nintedanib groups but reduced in the PBI-4050+pirfenidone group, suggesting a drug–drug interaction. There were no significant changes in forced vital capacity (FVC), either in % predicted or mL, from baseline to week 12 for PBI-4050 alone or PBI-4050+nintedanib. In contrast, a statistically significant reduction (p<0.024) in FVC % pred was seen for PBI-4050+pirfenidone after 12 weeks.

There were no safety concerns with PBI-4050 alone or in combination with nintedanib or pirfenidone in IPF patients. The stability of FVC between baseline and week 12 looked encouraging for PBI-4050 alone and in combination with nintedanib.

PBI-4050 alone and in combination with nintedanib demonstrated no safety concerns and showed encouraging results for lung function in IPF patientshttp://ow.ly/olQD30myD0E

The natural history of progressive fibrosing interstitial lung diseases

A proportion of patients with certain types of interstitial lung disease (ILD), including chronic hypersensitivity pneumonitis and ILDs associated with autoimmune diseases, develop a progressive fibrosing phenotype that shows similarities in clinical course to idiopathic pulmonary fibrosis. Irrespective of the clinical diagnosis, these progressive fibrosing ILDs show commonalities in the underlying pathogenetic mechanisms that drive a self-sustaining process of pulmonary fibrosis. The natural history of progressive fibrosing ILDs is characterized by decline in lung function, worsening of symptoms and health-related quality of life, and early mortality. Greater impairment in forced vital capacity or diffusion capacity of the lungs for carbon monoxide, and a greater extent of fibrotic changes on a computed tomography scan, are predictors of mortality in patients with fibrosing ILDs. However, the course of these diseases is heterogenous and cannot accurately be predicted for an individual patient. Data from ongoing clinical trials and patient registries will provide a better understanding of the clinical course and impact of progressive fibrosing ILDs.

Mechanical stress-induced mast cell degranulation activates TGF-β1 signalling pathway in pulmonary fibrosis

BACKGROUND

The role of mast cells accumulating in idiopathic pulmonary fibrosis (IPF) lungs is unknown.

OBJECTIVES

We investigated the effect of fibrotic extracellular matrix (ECM) on mast cells in experimental and human pulmonary fibrosis.

RESULTS

In IPF lungs, mast cell numbers were increased and correlated with disease severity (control vs 60%<FVC<90%, mean difference=-222.7, 95% CI -386.3 to -59.2, p=0.004; control vs FVC<60%, mean difference=-301.7, 95% CI of difference -474.1 to -129.34, p=0.0001; FVC>90% vs 60%<FVC<90%, mean difference=-189.6, 95% CI of difference -353.1 to -26.03, p=0.017; FVC>90% vs FVC<60%, mean difference=-268.6, 95% CI of difference -441.0 to -96.17, p=0.0007). Plasma tryptase levels were increased in IPF and negatively correlated with FVC (control vs FVC<60%, mean difference=-17.12, 95% CI of difference -30.02 to -4.22, p=0.006: correlation curves R=-0.045, p=0.025). In a transforming growth factor (TGF)-β1-induced pulmonary fibrosis model, chymase-positive and tryptase-positive mast cells accumulated in fibrotic lung. Lung tissue was decellularised and reseeded with bone marrow or peritoneum-derived mast cells; cells on fibrotic ECM released more TGF-β1 compared with normal ECM (active TGF-β1: bone marrow-derived mast cell (BMMC)-DL vs BMMC-TGF-β1 p=0.0005, peritoneal mast cell (PMC)-DL vs PMC-TGF-β1 p=0.0003, total TGF-β1: BMMC-DL vs BMMC-TGF-β1 p=0.013, PMC-DL vs PMC-TGF-β1 p=0.001). Mechanical stretch of lungs caused mast cell degranulation; mast cell stabilisers inhibited degranulation (histamine: cont vs doxantrazole p=0.004, β-hexosaminidase: cont vs doxantrazole, mean difference=1.007, 95% CI of difference 0.2700 to 1.744, p=0.007) and TGF-β1 activation (pSmad2/Smad2: cont vs dox p=0.006). Cromoglycate attenuated pulmonary fibrosis in rats (collagen: phosphate-buffered saline (PBS) vs cromoglycate p=0.036, fibrotic area: PBS vs cromoglycate p=0.031).

CONCLUSION

This study suggests that mast cells may contribute to the progression of pulmonary fibrosis.

Prostaglandin E2 inhibits profibrotic function of human pulmonary fibroblasts by disrupting Ca2+ signaling

We have shown that calcium (Ca²⁺) oscillations in human pulmonary fibroblasts (HPFs) contribute to profibrotic effects of transforming growth factor-β (TGF-β) and that disruption of these oscillations blunts features of pulmonary fibrosis. Prostaglandin E₂ (PGE₂) exerts antifibrotic effects in the lung, but the mechanisms for this action are not well defined. We thus sought to explore interactions between PGE₂ and the profibrotic agent TGF-β in pulmonary fibroblasts (PFs) isolated from patients with or without idiopathic pulmonary fibrosis (IPF). PGE₂ inhibited TGF-β-promoted [Ca²⁺] oscillations and prevented the activation of Akt and Ca²⁺/calmodulin-dependent protein kinase-II (CaMK-II) but did not prevent activation of Smad-2 or ERK. PGE₂ also eliminated TGF-β-stimulated expression of collagen A1, fibronectin, and α-smooth muscle actin and reduced stress fiber formation in the HPFs. RNA sequencing revealed that HPFs preferentially express EP₂ receptors relative to other prostanoid receptor subtypes: EP₂ expression is ~10-fold higher than that of EP₄ receptors; EP₁ and EP₃ receptors are barely detectable; and EP₂-receptor expression is ~3.5-fold lower in PFs from IPF patients than in normal HPFs. The inhibitory effects of PGE₂ on synthetic function and stress fiber formation were blocked by selective EP₂ or EP₄ antagonists and mimicked by selective EP₂ or EP₄ agonists, the phosphodiesterase inhibitor isobutylmethylxanthine and forskolin, all of which elevate cellular cAMP concentrations. We conclude that PGE₂, likely predominantly via EP₂ receptors, interferes with Ca²⁺ signaling, CaMK-II activation, and Akt activation in IPF-HPFs and HPFs treated with TGF-β. Moreover, a decreased expression of EP₂ receptors in pulmonary fibroblasts from IPF patients may contribute to the pathophysiology of this disease.

YAP1/Twist promotes fibroblast activation and lung fibrosis that conferred by miR-15a loss in IPF

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic parenchymal lung disease of unknown etiology and lack effective interventions. Using a combination of in vitro and in vivo studies, we found that overexpression of YAP1, a key effector in the Hippo pathway, promoted cell proliferation, migration, and collagen production in lung fibroblasts. Furthermore, the pro-fibrotic action of YAP1 was mediated by transcriptional activation of Twist1 through interacting with its partner TEAD. In contrast, knockdown of YAP1 inhibited extracellular matrix (ECM) deposition, which ultimately ameliorated lung fibrosis in vitro and in vivo. Additionally, we constructed a dysregulated miRNA regulatory network that affects the expression of the Hippo pathway effectors in IPF and identified miR-15a, which is significantly down-regulated in IPF patients, as one of the most essential miRNAs regulating this pathway. Moreover, knockdown of miR-15a resulted in fibroblast activation and lung fibrosis through promoting Twist expression by targeting inhibition of YAP1. In contrast, therapeutic restoration of miR-15a inhibits fibrogenesis in lung fibroblast and abrogated BLM-induced lung fibrosis in mice. These results highlight a role for miR-15a/YAP1/Twist axis in IPF that offer novel strategies for the prevention and treatment of lung fibrosis.

No relevant pharmacokinetic drug-drug interaction between nintedanib and pirfenidone

Nintedanib and pirfenidone are approved treatments for idiopathic pulmonary fibrosis (IPF). This open-label, two-group trial investigated the pharmacokinetic drug-drug interaction between these two drugs in patients with IPF.Subjects not treated with antifibrotics at screening (group 1, n=20) received a single nintedanib dose (150 mg) followed by pirfenidone (titrated to 801 mg thrice daily) for 3 weeks, with a further single nintedanib dose (150 mg) on the last day (day 23). Subjects treated with pirfenidone at screening (group 2, n=17) continued to receive pirfenidone alone (801 mg thrice daily) for 7 days, then co-administered with nintedanib (150 mg twice daily) for a further 7 days, before single doses of both treatments on day 16.In group 1, adjusted geometric mean (gMean) ratios (with/without pirfenidone) were 88.6% and 80.6% for nintedanib area under the plasma concentration-time curve (AUC) and maximum plasma concentration (C_max), respectively. In group 2, gMean ratios (with/without nintedanib) were 97.2% and 99.5% for pirfenidone AUC and C_max, respectively. For all parameters, the 90% confidence intervals included 100%, suggesting similar exposure for administration alone and when co-administered. Both treatments were well tolerated.These data indicate there is no relevant pharmacokinetic drug-drug interaction between nintedanib and pirfenidone when co-administered in IPF patients.

Macitentan reduces progression of TGF-β1-induced pulmonary fibrosis and pulmonary hypertension

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with an unknown cause. Two drugs, nintedanib and pirfenidone, have been shown to slow, but not stop, disease progression. Pulmonary hypertension (PH) is a frequent complication in IPF patients and is associated with poor prognosis. Macitentan is a dual endothelin receptor antagonist that is approved for pulmonary arterial hypertension treatment. We hypothesised that using macitentan to treat animals with pulmonary fibrosis induced by adenoviral vector encoding biologically active transforming growth factor-β1 (AdTGF-β1) would improve the PH caused by chronic lung disease and would limit the progression of fibrosis.Rats (Sprague Dawley) which received AdTGF-β1 were treated by daily gavage of macitentan (100 mg·kg^-1·day^-1), pirfenidone (0.5% food admix) or a combination from day 14 to day 28. Pulmonary artery pressure (PAP) was measured before the rats were killed, and fibrosis was subsequently evaluated by morphometric measurements and hydroxyproline analysis.AdTGF-β1 induced pulmonary fibrosis associated with significant PH. Macitentan reduced the increase in PAP and both macitentan and pirfenidone stopped fibrosis progression from day 14 to day 28. Macitentan protected endothelial cells from myofibroblast differentiation and apoptosis whereas pirfenidone only protected against fibroblast-to-myofibroblast differentiation. Both drugs induced apoptosis of differentiated myofibroblasts in vitro and in vivoOur results demonstrate that dual endothelin receptor antagonism was effective in both PH and lung fibrosis whereas pirfenidone only affected fibrosis.