Treatment of idiopathic pulmonary fibrosis with etanercept: an exploratory, placebo-controlled trial

Therapeutic Targeting of IL-11 for Chronic Lung Disease

Interleukin (IL)-11 was originally recognized as an immunomodulatory and hematopoiesis-inducing cytokine. However, although IL-11 is typically not found in healthy individuals, it is now becoming evident that IL-11 may play a role in diverse pulmonary conditions, including IPF, asthma, and lung cancer. Additionally, experimental strategies targeting IL-11, such as humanized antibodies, have recently been developed, revealing the therapeutic potential of IL-11. Thus, further insight into the underlying mechanisms of IL-11 in lung disease may lead to the ability to interfere with pathological conditions that have a clear need for disease-modifying treatments, such as IPF. In this review, we outline the effects, expression, signaling, and crosstalk of IL-11 and focus on its role in lung disease and its potential as a therapeutic target.

The Protective Effects of Nebulized Nano-Curcumin Against Bleomycin-Induced Pulmonary Fibrosis in Rats

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive fatal disease affecting the lung, and currently there is no efficient therapy for this condition. Curcumin, as a natural anti-inflammatory and antioxidant agent, could repress the pulmonary fibrosis (PF) caused by Bleomycin (BLM). Objectives: The aim of the research was to evaluate the protective activity of a nano-formulation of curcumin administered by inhalation on BLM-induced PF in rats. Methods: Eighty rats were randomly divided into eight experimental groups. Group one (control) that received saline intratracheally (IT) and subjected to vehicle inhalation. Group two to eight each received a single dose of BLM (5 IU/kg, IT) along with vehicle inhalation, oral prednisolone, oral curcumin, curcumin inhalation, and nano-curcumin inhalation with the doses of 50, 100, and 200 µg/kg, respectively. In the control and other groups, BLM was injected intratracheally on the first day of the experiment. In the treatment groups, curcumin suspension was prepared in distilled water and applied through nebulization for 21 consecutive days after BLM intratracheal administration. Then the rats were euthanized, and inflammatory cytokines (TNF-α, TGF-β, PDGF), hydroxyproline, and IL-10 (as a protective cytokine) were measured. Also, lung histopathological features were examined. Results: The synthesized nano-formulation reduced the overall hydroxyproline content of lungs in BLM-treated rats (P < 0.002). In addition, TNF-α, TGF-β, and PDGF levels significantly increased in the lungs of BLM-instilled rats (P < 0.001). However, the nano-formulation of curcumin (200 µg/kg) significantly decreased the levels of these inflammatory cytokines (P < 0.001) and increased IL-10 level (P = 0.0144) compared with the control group. Conclusions: The nebulization of nano-curcumin is suggested as a novel approach for the treatment of PF induced by BLM in rats. Our findings revealed that the inhalation (as a safe local drug delivery system approach) of the nano-curcumin at a dose of 200 µg/kg (formulated by cyclodextrin) could effectively protect the lung against PF.

Regulatory Immune Cells in Idiopathic Pulmonary Fibrosis: Friends or Foes?

The immune system is receiving increasing attention for interstitial lung diseases, as knowledge on its role in fibrosis development and response to therapies is expanding. Uncontrolled immune responses and unbalanced injury-inflammation-repair processes drive the initiation and progression of idiopathic pulmonary fibrosis. The regulatory immune system plays important roles in controlling pathogenic immune responses, regulating inflammation and modulating the transition of inflammation to fibrosis. This review aims to summarize and critically discuss the current knowledge on the potential role of regulatory immune cells, including mesenchymal stromal/stem cells, regulatory T cells, regulatory B cells, macrophages, dendritic cells and myeloid-derived suppressor cells in idiopathic pulmonary fibrosis. Furthermore, we review the emerging role of regulatory immune cells in anti-fibrotic therapy and lung transplantation. A comprehensive understanding of immune regulation could pave the way towards new therapeutic or preventive approaches in idiopathic pulmonary fibrosis.

Adherence, Persistence, and Effectiveness in Real Life. Multicenter Long-Term Study on the Use of Pirfenidone and Nintedanib in the Treatment of Idiopathic Pulmonary Fibrosis

BACKGROUND

In the treatment of idiopathic pulmonary fibrosis (IPF), nintedanib and pirfenidone, with their different mechanisms of action, lead to a reduction in the rate of progression of the fibrosis process measured by the reduction of functional decline, and, in particular, the decrease in forced vital capacity (FVC) and of the diffusion capacity of the lungs for carbon monoxide (DLCO). The objective of this study was to analyze real-life adherence, persistence and efficacy in the use of pirfenidone and nintedanib in the treatment of IPF.

METHODS

A non-interventional multicenter retrospective observational pharmacological study in real-life treat-ment at 1 and 2 years was conducted. Furthermore, we analyzed the levels of FVC and DLCO at 6 and 12 months, respectively, from the start of treatment.

RESULTS

We identified 144 patients in the period between January 2013 and April 2019. From the point of view of adherence, there is no difference between the two drugs, even though patients who used pirfenidone had increasingly higher values: 0.90 vs 0.89, in the first year, and 0.91 vs 0.84, in the second year. In the first year of treatment, the percentage of persistent patients was 67% and 76%, while in the second year, it dropped to 47% and 53% for pirfenidone and nintedanib, respectively.

CONCLUSION

The stratification of the adherence values as a function of the response to treatment in terms of FVC at 12 months for both study drugs showed that patients with optimal response scored adherence of more than 90%.

New Insights into Pathomechanisms and Treatment Possibilities for Lung Silicosis

Inhalation of silica particles is an environmental and occupational cause of silicosis, a type of pneumoconiosis. Development of the lung silicosis is a unique process in which the vicious cycle of ingestion of inhaled silica particles by alveolar macrophages and their release triggers inflammation, generation of nodular lesions, and irreversible fibrosis. The pathophysiology of silicosis is complex, and interactions between the pathomechanisms have not been completely understood. However, elucidation of silica-induced inflammation cascades and inflammation-fibrosis relations has uncovered several novel possibilities of therapeutic targeting. This article reviews new information on the pathophysiology of silicosis and points out several promising treatment approaches targeting silicosis-related pathways.

Prevention and Treatment of Stricturing Crohn's Disease - Perspectives and Challenges

Introduction: Fibrostenosis is a hallmark of Crohn's disease (CD), remains a challenge in today's clinical management of inflammatory bowel disease patients and represents a key event in the disease course necessitating improved preventative strategies and a multidisciplinary approach to diagnosis and management. With the advent of anti-fibrotic therapies and well-defined clinical endpoints for stricturing CD, there is promise to impact the natural history of disease.Areas covered: This review summarizes current evidence in the natural history of stricturing Crohn's disease, discusses management approaches as well as future perspectives on intestinal fibrosis.Expert opinion: Currently, there are no specific therapies to prevent progression to fibrosis or to treat it after it becomes clinically apparent. In addition to the international effort by the Stenosis Therapy and Anti-Fibrotic Research (STAR) consortium to standardize definitions and propose endpoints in the management of stricturing CD, further research to improve our understanding of mechanisms of intestinal fibrosis will help pave the way for the development of future anti-fibrotic therapies.

Therapeutic targets in lung tissue remodelling and fibrosis

Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-β induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.

Immune dysregulation as a driver of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) affects hundreds of thousands of people worldwide, reducing their quality of life and leading to death from respiratory failure within years of diagnosis. Treatment options remain limited, with only two FDA-approved drugs available in the United States, neither of which reverse the lung damage caused by the disease or prolong the life of individuals with IPF. The only cure for IPF is lung transplantation. In this review, we discuss recent major advances in our understanding of the role of the immune system in IPF that have revealed immune dysregulation as a critical driver of disease pathophysiology. We also highlight ways in which an improved understanding of the immune system's role in IPF may enable the development of targeted immunomodulatory therapies that successfully halt or potentially even reverse lung fibrosis.

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.

Endothelial cells, neutrophils and platelets: getting to the bottom of an inflammatory triangle

Severe fibrotic and thrombotic events permeate the healthcare system, causing suffering for millions of patients with inflammatory disorders. As late-state consequences of chronic inflammation, fibrosis and thrombosis are the culmination of pathological interactions of activated endothelium, neutrophils and platelets after vessel injury. Coupling of these three cell types ensures a pro-coagulant, cytokine-rich environment that promotes the capture, activation and proliferation of circulating immune cells and recruitment of key pro-fibrotic cell types such as myofibroblasts. As the first responders to sterile inflammatory injury, it is important to understand how endothelial cells, neutrophils and platelets help create this environment. There has been a growing interest in this intersection over the past decade that has helped shape the development of therapeutics to target these processes. Here, we review recent insights into how neutrophils, platelets and endothelial cells guide the development of pathological vessel repair that can also result in underlying tissue fibrosis. We further discuss recent efforts that have been made to translate this knowledge into therapeutics and provide perspective as to how a compound or combination therapeutics may be most efficacious when tackling fibrosis and thrombosis that is brought upon by chronic inflammation.

Identification of key modules and hub genes associated with lung function in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease, characterized by a decline in lung function. To date, the pathophysiologic mechanisms associated with lung dysfunction remain unclear, and no effective therapy has been identified to improve lung function.

Methods

In the present study, we used weighted gene co-expression network analysis (WGCNA) to identify key modules and hub genes associated with lung function in IPF. Three datasets, containing clinical information, were downloaded from Gene Expression Omnibus. WGCNA was performed on the GSE32537 dataset. Differentially expressed gene s (DEGs) between IPF patients and healthy controls were also identified to filter hub genes. The relationship between hub genes and lung function was then validated using the GSE47460 and GSE24206 datasets.

Results

The red module, containing 267 genes, was positively correlated with the St. George’s Respiratory Questionnaire score (r = 0.37, p < 0.001) and negatively correlated with the percent predicted forced vital capacity (FVC% predicted) (r =  − 0.46, p < 0.001) and the percent predicted diffusion capacity of the lung for carbon monoxide (Dlco% predicted) (r =  − 0.42, p < 0.001). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis suggested that the genes in the red module were primarily involved in inflammation and immune pathways. Based on Module Membership and Gene Significance, 32 candidate hub genes were selected in the red module to construct a protein-protein interaction network . Based on the identified DEGs and the degree of connectivity in the network, we identified three hub genes, including interleukin 6 (IL6), suppressor of cytokine signaling-3 (SOCS3), and serpin family E member 1 (SERPINE1). In the GSE47460 dataset, Spearman correlation coefficients between Dlco% predicted and expression levels of IL6, SERPINE1, SOCS3 were –0.32, –0.41, and –0.46, respectively. Spearman correlation coefficients between FVC% predicted and expression levels of IL6, SERPINE1, SOCS3 were –0.29, –0.33, and –0.27, respectively. In the GSE24206 dataset, all three hub genes were upregulated in patients with advanced IPF.

Conclusion

We identified three hub genes that negatively correlated with the lung function of IPF patients. Our results provide insights into the pathogenesis underlying the progressive disruption of lung function, and the identified hub genes may serve as biomarkers and potential therapeutictargets for the treatment of IPF patients.

Fibroblast-enriched endoplasmic reticulum protein TXNDC5 promotes pulmonary fibrosis by augmenting TGFβ signaling through TGFBR1 stabilization

Pulmonary fibrosis (PF) is a major public health problem with limited therapeutic options. There is a clear need to identify novel mediators of PF to develop effective therapeutics. Here we show that an ER protein disulfide isomerase, thioredoxin domain containing 5 (TXNDC5), is highly upregulated in the lung tissues from both patients with idiopathic pulmonary fibrosis and a mouse model of bleomycin (BLM)-induced PF. Global deletion of Txndc5 markedly reduces the extent of PF and preserves lung function in mice following BLM treatment. Mechanistic investigations demonstrate that TXNDC5 promotes fibrogenesis by enhancing TGFβ1 signaling through direct binding with and stabilization of TGFBR1 in lung fibroblasts. Moreover, TGFβ1 stimulation is shown to upregulate TXNDC5 via ER stress/ATF6-dependent transcriptional control in lung fibroblasts. Inducing fibroblast-specific deletion of Txndc5 mitigates the progression of BLM-induced PF and lung function deterioration. Targeting TXNDC5, therefore, could be a novel therapeutic approach against PF.

Pulmonary fibrosis is a major public health problem with unclear mechanism and limited therapeutic options. Here the authors show that a fibroblast-enriched endoplasmic reticulum protein, TXNDC5, promotes pulmonary fibrosis by stabilizing TGFBR1 and show the potential of TXNDC5 as a therapeutic target against pulmonary fibrosis.

Cellular signalling pathways mediating the pathogenesis of chronic inflammatory respiratory diseases: an update

Respiratory disorders, especially non-communicable, chronic inflammatory diseases, are amongst the leading causes of mortality and morbidity worldwide. Respiratory diseases involve multiple pulmonary components, including airways and lungs that lead to their abnormal physiological functioning. Several signaling pathways have been reported to play an important role in the pathophysiology of respiratory diseases. These pathways, in addition, become the compounding factors contributing to the clinical outcomes in respiratory diseases. A range of signaling components such as Notch, Hedgehog, Wingless/Wnt, bone morphogenetic proteins, epidermal growth factor and fibroblast growth factor is primarily employed by these pathways in the eventual cascade of events. The different aberrations in such cell-signaling processes trigger the onset of respiratory diseases making the conventional therapeutic modalities ineffective. These challenges have prompted us to explore novel and effective approaches for the prevention and/or treatment of respiratory diseases. In this review, we have attempted to deliberate on the current literature describing the role of major cell signaling pathways in the pathogenesis of pulmonary diseases and discuss promising advances in the field of therapeutics that could lead to novel clinical therapies capable of preventing or reversing pulmonary vascular pathology in such patients.

Mechanical ventilation for acute respiratory failure due to idiopathic pulmonary fibrosis versus connective tissue disease-associated interstitial lung disease: Effectiveness and risk factors for death

INTRODUCTION

Relatively little is known about the effects of mechanical ventilation (MV; including invasive MV [IMV] and noninvasive ventilation) on clinical outcomes of patients with idiopathic pulmonary fibrosis (IPF) and connective tissue disease-associated interstitial lung disease (CTD-ILD) in the intensive care unit (ICU) and risk factors for ICU death remain to be determined.

OBJECTIVES

Our objective was to determine and compare mortality rates between IPF and CTD-ILD patients receiving MV and to identify risk factors for ICU death in these patients.

METHODS

We conducted a retrospective cohort study in respiratory ICUs of three university hospitals in China during a 7-year period. We compared clinical data and outcomes between patients with IPF and those with CTD-ILD and performed logistic regression analyses to identify risk factors for ICU death.

RESULTS

Of the 94 patients in the analyses, 63 were diagnosed with IPF and 31 were diagnosed with CTD-ILD. ICU mortality was significantly higher in the IPF group than in the CTD-ILD group (86% vs 68%; P = 0.041) and was significantly lower in patients receiving noninvasive ventilation than in those receiving IMV (62% vs 88%; P = 0.004). Risk factors for ICU death were disease progression as the principal cause of acute respiratory failure and IMV.

CONCLUSION

Based on current clinical practice in three ICUs, the mortality rate in IPF patients receiving MV might reach 86% and is higher than in CTD-ILD patients. IMV might be initiated cautiously, especially in patients with disease progression as the principal cause of acute respiratory failure.

Evolution and treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and devastating disease of unknown etiology, characterized by irreversible morphological changes, ultimately leading to lung fibrosis and death. In recent years, significant progress has been achieved in understanding the pathogenesis of IPF. Moreover, we assisted to the conceptual change of the pathogenic hypothesis that currently considers IPF as a primarily fibrotic driven disease. However, despite the undeniable progress, the diagnosis of IPF remains still very complex requiring the presence of a team of experts to achieve the highest level of diagnostic confidence. The advent of antifibrotics has radically changed the treatment landscape of IPF and new promising drugs are currently under evaluation. Furthermore, a more extensive use of non-pharmacological treatments has also to be encouraged in all patients both to reduce symptoms and improve quality of life.

Treatment of Rheumatoid Arthritis-Associated Interstitial Lung Disease: Lights and Shadows

Rheumatoid arthritis (RA) is a chronic and systemic inflammatory disease affecting 0.5–1% of the population worldwide. Interstitial lung disease (ILD) is a serious pulmonary complication of RA and it is responsible for 10–20% of mortality, with a mean survival of 5–8 years. However, nowadays there are no therapeutic recommendations for the treatment of RA-ILD. Therapeutic options for RA-ILD are complicated by the possible pulmonary toxicity of many disease modifying anti-rheumatic drugs (DMARDs) and by their unclear efficacy on pulmonary disease. Therefore, joint and lung involvement should be evaluated independently of each other for treatment purposes. On the other hand, some similarities between RA-ILD and idiopathic pulmonary fibrosis and the results of the recent INBIULD trial suggest a possible future role for antifibrotic agents. From this perspective, we review the current literature describing the pulmonary effects of drugs (immunosuppressants, conventional, biological and target synthetic DMARDs and antifibrotic agents) in patients with RA and ILD. In addition, we suggest a framework for the management of RA-ILD patients and outline a research agenda to fill the gaps in knowledge about this challenging patient cohort.

Brazilian guidelines for the pharmacological treatment of idiopathic pulmonary fibrosis. Official document of the Brazilian Thoracic Association based on the GRADE methodology

Idiopathic pulmonary fibrosis (IPF) is a form of chronic interstitial lung disease of unknown cause, which predominantly affects elderly men who are current or former smokers. Even though it is an uncommon disease, it is of great importance because of its severity and poor prognosis. In recent decades, several pharmacological treatment modalities have been investigated for the treatment of this disease, and the classic concepts have therefore been revised. The purpose of these guidelines was to define evidence-based recommendations regarding the use of pharmacological agents in the treatment of IPF in Brazil. We sought to provide guidance on the practical issues faced by clinicians in their daily lives. Patients of interest, Intervention to be studied, Comparison of intervention and Outcome of interest (PICO)-style questions were formulated to address aspects related to the use of corticosteroids, N-acetylcysteine, gastroesophageal reflux medications, endothelin-receptor antagonists, phosphodiesterase-5 inhibitors, pirfenidone, and nintedanib. To formulate the PICO questions, a group of Brazilian specialists working in the area was assembled and an extensive review of the literature on the subject was carried out. Previously published systematic reviews with meta-analyses were analyzed for the strength of the compiled evidence, and, on that basis, recommendations were developed by employing the Grading of Recommendations Assessment, Development and Evaluation approach. The authors believe that the present document represents an important advance to be incorporated in the approach to patients with IPF, aiming mainly to improve its management, and can become an auxiliary tool for defining public policies related to IPF.

A pathologic two-way street: how innate immunity impacts lung fibrosis and fibrosis impacts lung immunity

Lung fibrosis is characterised by the accumulation of extracellular matrix within the lung and is secondary to both known and unknown aetiologies. This accumulation of scar tissue limits gas exchange causing respiratory insufficiency. The pathogenesis of lung fibrosis is poorly understood, but immunologic‐based treatments have been largely ineffective. Despite this, accumulating evidence suggests that innate immune cells and receptors play important modulatory roles in the initiation and propagation of the disease. Paradoxically, while innate immune signalling may be important for the pathogenesis of fibrosis, there is also evidence to suggest that innate immune function against pathogens may be impaired, leading to dysregulated and/or impaired host defence. This review summarises the evidence for this pathologic two‐way street, highlights new concepts of pathogenesis and recommends future directions for research emphasis.

Differing severities of acute exacerbations of idiopathic pulmonary fibrosis (IPF): insights from the INPULSIS® trials

Background

Given the broad definition of an acute exacerbation of IPF, it is likely that acute exacerbations are heterogeneous in their aetiology, severity and clinical course. We used pooled data from the INPULSIS® trials of nintedanib versus placebo to investigate whether acute exacerbations reported as serious adverse events were associated with higher mortality than those reported as non-serious adverse events and to assess the effect of nintedanib on these types of events.

Methods

Adverse events considered by an investigator to be an acute exacerbation were adjudicated as a confirmed acute exacerbation, suspected acute exacerbation, or not an acute exacerbation. Time to first investigator-reported acute exacerbation or confirmed/suspected acute exacerbation reported as a serious adverse event or non-serious adverse event over the 52-week treatment period was assessed post-hoc. Deaths were assessed based on data collected over the 52-week treatment period.

Results

Of 63 patients who had ≥1 investigator-reported acute exacerbation, 48 (76.2%) had a first acute exacerbation reported as a serious adverse event. Thirty-six (3.4%) patients had ≥1 confirmed/suspected acute exacerbation, of whom 31 had a first event reported as a serious adverse event. Investigator-reported acute exacerbations reported as serious adverse events occurred in 23 patients in the nintedanib group and 26 in the placebo group. Confirmed/suspected acute exacerbations reported as serious adverse events occurred in 10 and 21 patients in these groups, respectively. Nintedanib significantly reduced the risk of a first acute exacerbation reported as a serious adverse event (HR 0.57 [95% CI: 0.32, 0.99]; p = 0.0476) and the risk of a first confirmed/suspected acute exacerbation reported as a serious adverse event (HR 0.30 [95% CI: 0.14, 0.64]; p = 0.0019) versus placebo. A higher proportion of patients with investigator-reported acute exacerbations reported as serious adverse events died than patients with acute exacerbations reported as non-serious adverse events (61.2% versus 7.1%).

Conclusion

Different severities of acute exacerbation of IPF may exist. Acute exacerbations reported as serious adverse events in the INPULSIS® trials were associated with high mortality. Nintedanib significantly reduced the risk of acute exacerbations reported as serious adverse events.

Trial registration

ClinicalTrials.govNCT01335464 and NCT01335477.

Biologic Treatments in Interstitial Lung Diseases

Interstitial lung diseases (ILD) represent a group of heterogeneous parenchymal lung disorders with complex pathophysiology, characterized by different clinical and radiological patterns, ultimately leading to pulmonary fibrosis. A considerable proportion of these disease entities present with no effective treatment, as current therapeutic regimens only slow down disease progression, thus leaving patients, at best case, with considerable functional disability. Biologic therapies have emerged and are being investigated in patients with different forms of ILD. Unfortunately, their safety profile has raised many concerns, as evidence shows that they might cause or exacerbate ILD status in a subgroup of patients. This review article aims to summarize the current state of knowledge on their role in patients with ILD and highlight future perspectives.

Dually Efficacious Medicine Against Fibrosis and Cancer

Although there is a contemporary consensus of managing a severe disease with multi-targeted approach-based therapeutic combinations, it should not be ignored that certain patho-biological pathways are shared by distinct medical conditions and can be exploited to develop an exceptional type of medication conferring a dual efficacy. This article thus presents a spectrum of emerging molecular targets that substantially contribute to the pathogenesis of both fibrotic and neoplastic disorders, including kinase activities, cytokine cascades, and protein dynamics among others. Moreover, recently approved therapeutic agents in this regard have been sorted out to corroborate the drug’s ability upon targeting each one of these molecular pathways to treat fibrosis and cancer simultaneously. It not only streamlines an overlapping mechanistic profile in the pathogenesis across these two medical conditions, but also inspires clinicians and pharmaceutical innovation to tackle concomitant diseases, such as fibrosis and cancer, with an optimally efficacious medication.

Psychometric properties and minimal important differences of SF-36 in Idiopathic Pulmonary Fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a rare disease with a median survival of 3-5 years after diagnosis with limited treatment options. The aim of this study is to assess the psychometric characteristics of the Short Form 36 Health Status Questionnaire (SF-36) in IPF and to provide disease specific minimally important differences (MID).

METHODS

Data source was the European IPF Registry (eurIPFreg). The psychometric properties of the SF-36 version 2 were evaluated based on objective clinical measures as well as subjective perception. We analysed acceptance, feasibility, discrimination ability, construct and criterion validity, responsiveness and test-retest-reliability. MIDs were estimated via distribution and anchor-based approaches.

RESULTS

The study population included 258 individuals (73.3% male; mean age 67.3 years, SD 10.7). Of them 75.2% (194 individuals) had no missing item. The distribution of several items was skewed, although floor effect was acceptable. Physical component score (PCS) correlated significantly and moderately with several anchors, whereas the correlations of mental component score (MCS) and anchors were only small. The tests showed mainly significant lower HRQL in individuals with long-term oxygen therapy. Analyses in stable individuals did not show significant changes of HRQL except for one dimension and anchor. Individuals with relevant changes of the health status based on the anchors had significant changes in all SF-36 dimensions and summary scales except for the dimension PAIN. PCS and MCS had mean MIDs of five and six, respectively. Mean MIDs of the dimensions ranged from seven to 21.

CONCLUSION

It seems that the SF-36 is a valid instrument to measure HRQL in IPF and so can be used in RCTs or individual monitoring of disease. Nevertheless, the additional evaluation of longitudinal aspects and MIDs can be recommended to further analyse these factors. Our findings have a great potential impact on the evaluation of IPF patients.

TRIAL REGISTRATION

The eurIPFreg and eurIPFbank are listed in https://clinicaltrials.gov ( NCT02951416 ).

TRAIL signals through the ubiquitin ligase MID1 to promote pulmonary fibrosis

BACKGROUND

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) has previously been demonstrated to play a pro-inflammatory role in allergic airways disease and COPD through the upregulation of the E3 ubiquitin ligase MID1 and the subsequent deactivation of protein phosphatase 2A (PP2A).

METHODS

Biopsies were taken from eight IPF patients presenting to the Second Affiliated Hospital of Jilin University, China between January 2013 and February 2014 with control samples obtained from resected lung cancers. Serum TRAIL, MID1 protein and PP2A activity in biopsies, and patients' lung function were measured. Wild type and TRAIL deficient Tnfsf10-/- BALB/c mice were administered bleomycin to induce fibrosis and some groups were treated with the FTY720 analogue AAL(s) to activate PP2A. Mouse fibroblasts were treated with recombinant TRAIL and fibrotic responses were assessed.

RESULTS

TRAIL in serum and MID1 protein levels in biopsies from IPF patients were increased compared to controls. MID1 levels were inversely associated while PP2A activity levels correlated with DLco. Tnfsf10-/- and mice treated with the PP2A activator AAL(s) were largely protected against bleomycin-induced reductions in lung function and fibrotic changes. Addition of recombinant TRAIL to mouse fibroblasts in-vitro increased collagen production which was reversed by PP2A activation with AAL(s).

CONCLUSION

TRAIL signalling through MID1 deactivates PP2A and promotes fibrosis with corresponding lung function decline. This may provide novel therapeutic targets for IPF.

Attenuation of lipopolysaccharide-induced lung inflammation by ascorbic acid in rats: Histopathological and ultrastructural study

Introduction:

Lipopolysaccharide is a bacterial endotoxin that induces acute lung injury in experimental animals, which is similar to acute respiratory distress syndrome in humans. The induced tissue trauma ends in fibrosis. Understanding the pathogenesis is important in the prevention and treatment of the complications. This study was assigned to investigate the long-term lipopolysaccharide-induced lung injury and the postulated protective effect of ascorbic acid on these changes.

Materials and methods:

Twenty-four adult male albino rats were divided into three groups. Group I was the controls, group II received lipopolysaccharide and group III received lipopolysaccharide and ascorbic acid. After 30 days of starting treatment, lung tissue samples were obtained.

Results:

Group II lung tissues showed marked thickening of the alveolar septa with collapsed alveolar sacs, detached bronchial epithelium, inflammatory cell infiltration and excessive deposition of collagen. Group III showed mild thickening of the alveolar walls, scanty inflammatory cell infiltration, mild parabronchial fibrosis and less marked collagen deposition. α-Smooth muscle actin staining of group II showed marked expression of the actin-positive cells. Less potential expression of the dye was found in group III. Ultrastructural examination of group II showed evident structural changes in pneumocytes with capillary basement membrane irregularity and interruption compared to uniform basement membrane in group III with less prominent intracellular changes in pneumocytes.

Conclusion:

Ascorbic acid attenuated the inflammatory response and fibrosis in the lungs of rats treated with lipopolysaccharide as evidenced by the histological, immunohistochemical and ultrastructural studies.

Utility of the six-minute walk test in patients with idiopathic pulmonary fibrosis

The six-minute walk test (6MWT) is a simple test that is widely used to assess functional exercise capacity in patients with idiopathic pulmonary fibrosis (IPF). Patients with IPF have reduced exercise capacity due to a number of factors, such as impaired respiratory mechanics and circulatory problems. As a self-paced and usually submaximal exercise test, the 6MWT reflects the exercise level of everyday activities. Variables measured during the 6MWT, such as six-minute walk distance (6MWD) and desaturation, are strong predictors of mortality in patients with IPF. However, the results of a 6MWT are affected by numerous factors, including age, body size, comorbidities and the use of supplemental oxygen during the test, and these need to be borne in mind when interpreting the results of individual and serial tests. Clinical studies, including trials of potential therapies for IPF, have differed in the methodology used to implement the 6MWT, hindering the comparison of results across studies. In this review, I describe the utility of the 6MWT in patients with IPF and provide recommendations for standardisation of the test for use both in clinical practice and research. A brief video on how to set up and administer the 6MWT is available at http://www.usscicomms.com/respiratory/lancaster/6mwt/

Combination of Salvia miltiorrhiza and ligustrazine attenuates bleomycin-induced pulmonary fibrosis in rats via modulating TNF-α and TGF-β

Background

Idiopathic pulmonary fibrosis (IPF), a chronic, progressive, fibrosing interstitial lung disease, is associated with extremely poor prognosis, and lacks effective treatment. The frequently used immunosuppressive therapies such as dexamethasone (DEX) are often associated with side effects. Recently, combination of two Chinese herbal medicine preparations, Salvia miltiorrhiza and ligustrazine (SML), serves as an alternative medicine for treatment of IPF in clinical practices in China. The aim of this study is to compare the anti-fibrotic effect of SML with that of DEX and to investigate the underlying mechanisms.

Methods

A rat model of bleomycin (BLM) induced pulmonary fibrosis was used in this study. Ninety rats were assigned to six groups: control group; BLM-group; BLM and dexamethasone group (BLM + DEX); BLM + low-dose SML; BLM + medium-dose SML and BLM + high-dose SML. Rats were sacrificed on day 7, 14 and 28 after treatment. The extent of alveolitis and fibrosis was observed by H&E and Masson’s trichrome staining. The expressions of TNF-α, TGF-β1 and SMAD4 were determined and quantified by immunohistochemical analysis. The serum levels of TNF-α and TGF-β1 were further quantified by ELISA kits.

Results

Both DEX and SML treatment attenuated BLM-induced lung injury and pathological collagen deposition in rats, showing improved alveolitis and fibrosis scores on day 7, 14, 28, compared to the BLM group (p < 0.05). The anti-fibrotic effect of SML was in a dose-dependent manner, and the medium- and high-dose SML showed comparable effect with DEX on day 14 and 28. Expressions of TNF-α, TGF-β1 and SMAD4 were significantly decreased in the DEX- and SML-treated groups compared with BLM groups (p < 0.05). Medium- and high-dose SML showed better repression of TNF-α, TGF-β1 and SMAD4 expression compared to DEX at all time points (p < 0.05). Notably, SML at different dosages did not affect serum levels of alanine aminotransferase, aspartate aminotransferase and creatinine.

Conclusions

SML is safe and effective in repressing BLM-induced pulmonary fibrosis, which might be through modulating the expression of TNF-α and TGF-β1. Our findings advocate the use of SML for IPF, which might serve as a better treatment option over DEX.

Electronic supplementary material

The online version of this article (10.1186/s13020-018-0194-9) contains supplementary material, which is available to authorized users.

The Burden of Illness of Idiopathic Pulmonary Fibrosis: A Comprehensive Evidence Review

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a debilitating condition with significant morbidity and poor survival. Since 2010, there has been increased activity in the development of treatments that aim to delay progression of the disease.

OBJECTIVE

Our study involves a comprehensive review of the literature for evidence on health-related quality of life (HRQoL), healthcare resource use (HCRU) and costs, and an assessment of the burden of illness of the condition.

METHODS

We carried out a systematic literature review (SLR) to identify economic evaluations and HRQoL studies. We searched EMBASE, MEDLINE and MEDLINE In Process for relevant studies from database origins to April 2017. Alongside the presentation of the study characteristics and the available evidence, we carried out a qualitative comparison using reference population estimates for HRQoL and national health expenditure for costs.

RESULTS

Our search identified a total of 3241 records. After removing duplicates and not relevant articles, we analysed 124 publications referring to 88 studies published between 2000 and 2017. Sixty studies were HRQoL and 28 were studies on costs or HCRU. We observed an exponential growth of publications in the last 3-5 years, with the majority of the studies conducted in Europe and North America. Among the HRQoL studies, and despite regional differences, there was some agreement between estimates on the absolute and relative level of HRQoL for patients with IPF compared with the general population. Regarding costs, after adjustments for the cost years and currency, the suggested annual per capita cost of patients with IPF in North America was estimated around US$20,000, 2.5-3.5 times higher than the national healthcare expenditure. Additionally, studies that analysed patients with IPF alongside a matched control cohort suggested a significant increase in resource use and cost.

CONCLUSION

The reviewed evidence indicates that IPF has considerable impact on HRQoL, relative to the general population levels. Furthermore, in studies of cost and resource use, most estimates of the burden were consistent in suggesting an excess cost for patients with IPF compared with a control cohort or the national health expenditure. This confirms IPF as a growing threat for public health worldwide, with considerable impact to the patients and healthcare providers.

The Role of Immune and Inflammatory Cells in Idiopathic Pulmonary Fibrosis

The contribution of the immune system to idiopathic pulmonary fibrosis (IPF) remains poorly understood. While most sources agree that IPF does not result from a primary immunopathogenic mechanism, evidence gleaned from animal modeling and human studies suggests that innate and adaptive immune processes can orchestrate existing fibrotic responses. This review will synthesize the available data regarding the complex role of professional immune cells in IPF. The role of innate immune populations such as monocytes, macrophages, myeloid suppressor cells, and innate lymphoid cells will be discussed, as will the activation of these cells via pathogen-associated molecular patterns derived from invading or commensural microbes, and danger-associated molecular patterns derived from injured cells and tissues. The contribution of adaptive immune responses driven by T-helper cells and B cells will be reviewed as well. Each form of immune activation will be discussed in the context of its relationship to environmental and genetic factors, disease outcomes, and potential therapies. We conclude with discussion of unanswered questions and opportunities for future study in this area.

Global Gene Expression Analysis in an in vitro Fibroblast Model of Idiopathic Pulmonary Fibrosis Reveals Potential Role for CXCL14/CXCR4

Idiopathic Pulmonary Fibrosis (IPF) is a progressive disorder that is marked by an over accumulation of activated fibroblast populations. Despite the improved understanding of many mechanisms within this disease, global gene expression analysis has few focused studies on the fibroblast, the central effector cell of progressive fibrosis. We present a unique analysis of IPF pulmonary fibroblasts as they transition through cell culture and identify in vitro altered cellular processes. Fibroblasts were isolated from diseased (n = 8) and non-diseased (n = 4) lungs. Global gene expression analysis was carried out at the initial point of isolation and after 3 weeks of culture. We identify several genes that are altered by removal of the fibroblast from the IPF environment. Comparison of this subset of genes to four previously published whole lung analyses refined our list to a small subset of key fibroblast specific genes important in IPF. Application of STRING database analysis and confirmation via in-vitro and histological assay highlights the CXCL14/CXCR4 chemokine axis with a possible role in the progression and/or activation of fibroblasts within the IPF lung. Our findings, present a possible therapeutic target for IPF and a model for the study and discovery of novel protein and processes in this terrible disease.

Drugs and Targets in Fibrosis

Fibrosis contributes to the development of many diseases and many target molecules are involved in fibrosis. Currently, the majority of fibrosis treatment strategies are limited to specific diseases or organs. However, accumulating evidence demonstrates great similarities among fibroproliferative diseases, and more and more drugs are proved to be effective anti-fibrotic therapies across different diseases and organs. Here we comprehensively review the current knowledge on the pathological mechanisms of fibrosis, and divide factors mediating fibrosis progression into extracellular and intracellular groups. Furthermore, we systematically summarize both single and multiple component drugs that target fibrosis. Future directions of fibrosis drug discovery are also proposed.

New insights on patient-reported outcome measures in idiopathic pulmonary fibrosis: only PROMises?

PURPOSE OF REVIEW

In a chronic, progressive and ultimately fatal disease like idiopathic pulmonary fibrosis (IPF), the maintenance of patients' quality of life should be regarded as a major aim of treatment. Although better knowledge and two antifibrotic drugs are now available in IPF, the individual response to treatment and its acceptance remain poorly explored. This review summarizes recent advances in research on patient-reported outcomes and their measures, indispensable instruments to investigate how patients feel and function, and how the disease impacts their lives.

RECENT FINDINGS

In IPF, there is a paucity of specific well-validated patient-reported outcome measures (PROMs). The use of generic PROMs in past IPF trials revealed a poor correlation of such questionnaires with established endpoints of treatment response. Several attempts are currently ongoing to develop specific IPF PROMs. The King's Brief Interstitial Lung Disease health status questionnaire and the Tool to Assess Quality of Life in IPF are promising questionnaires developed by using institutional recommendations and are currently being validated in large cohorts.

SUMMARY

Well-validated relevant PROMs can be employed for multiple purposes: as outcome measures for daily care or for driving therapeutic decisions, as efficacy endpoints in clinical trials, or as tools to collect useful data for healthcare policy makers in order to improve access and quality of care.

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

Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal disease. A major breakthrough in treatment came when, after decades of clinical trials which failed to identify an efficacious treatment regimen, two therapies were successful in Phase-III trials. The advent of these therapies, nintedanib and pirfenidone, meant that for the first time IPF patients had two treatment options that could reduce disease progression. This review summarises the key lessons to be obtained from the clinical trials that led to the current international clinical practice guidelines for the treatment of IPF and provides insights for the design of future clinical trials that are needed if we are to improve outcomes that are clinically meaningful to IPF patients.

The disturbed redox-balance in pulmonary fibrosis is modulated by the plant flavonoid quercetin

Idiopathic pulmonary fibrosis (IPF) is characterized by a disturbed pulmonary redox balance associated with inflammation. To restore this balance, antioxidants are often suggested as therapy for IPF but previous clinical trials with these compounds and their precursors have not been successful in the clinic. The exogenous antioxidant quercetin, which has a versatile antioxidant profile and is effective in restoring a disturbed redox balance, might be a better candidate. The aim of this study was to evaluate the protective effect of quercetin on oxidative and inflammatory markers in IPF. Here, we demonstrate that IPF patients have a significantly reduced endogenous antioxidant defense, shown by a reduced total antioxidant capacity and lowered glutathione and uric acid levels compared to healthy controls. This confirms that the redox balance is disturbed in IPF. Ex vivo incubation with quercetin in blood of both IPF patients and healthy controls reduces LPS-induced production of the pro-inflammatory cytokines IL-8 and TNFα. This anti-inflammatory effect was more pronounced in the blood of the patients. Our pro-fibrotic in vitro model, consisting of bleomycin-triggered BEAS-2B cells, shows that quercetin boosts the antioxidant response, by increasing Nrf2 activity, and decreases pro-inflammatory cytokine production in a concentration-dependent manner. Collectively, our findings implicate that IPF patients may benefit from the use of quercetin to restore the disturbed redox balance and reduce inflammation.

Model-based Meta-Analysis on the Efficacy of Pharmacological Treatments for Idiopathic Pulmonary Fibrosis

Recently, the US Food and Drug Administration (FDA) approved the first two drugs (pirfenidone and nintedanib) indicated for the treatment of idiopathic pulmonary fibrosis (IPF). The purpose of this analysis was to leverage publicly available data to quantify comparative efficacy of compounds that are approved or in development. An analysis-ready database was developed, and the analysis dataset is composed of summary-level data from 43 arms in 20 trials, with treatment durations ranging from 8-104 weeks. A hierarchical multivariable regression model with nonparametric placebo estimation was used to fit the longitudinal profile of change from baseline of percent predicted forced vital capacity (%predicted FVC) data. Pirfenidone and nintedanib were the only drugs identified to have significant estimated positive treatment effects. Model simulations were performed to further evaluate the covariate and time course of treatment effects on longitudinal change from baseline %predicted FVC to inform future trial designs and support decision making.

Pharmacotherapy for idiopathic pulmonary fibrosis: current landscape and future potential

Over the past two and a half decades, many clinical trials have been designed to determine the safety and efficacy of pharmacotherapy for patients with idiopathic pulmonary fibrosis (IPF). However, so far, only two drugs (pirfenidone and nintedanib) have been found to have an impact on disease progression as defined by reducing the rate of decline in forced vital capacity over a year among IPF patients with mild to moderate impairment in lung function. These two drugs have been approved for treatment of IPF by regulatory agencies and are currently in clinical use worldwide. This article summarises the current landscape of pharmacotherapy for IPF and highlights the prospects and potential of new therapies that are currently being pursued in clinical trials.

The landscape of treatment for IPF is on new turf with nintedanib, pirfenidone and new clinical trialshttp://ow.ly/bav230eQPgl

Cholesterol-modified Hydroxychloroquine-loaded Nanocarriers in Bleomycin-induced Pulmonary Fibrosis

An increasing number of reports have suggested the use of hydroxychloroquine (HCQ) as an adjunct anti-cancer treatment to enhance the chemotherapeutic response, as well as for the treatment of several fibrotic skin diseases and cystic fibrosis. In this study, we synthesized a cholesterol-modified HCQ (Chol-HCQ) and hypothesized that a systemic delivery system with Chol-HCQ nanocarriers could be effective for the treatment of bleomycin-induced pulmonary fibrosis. Chol-HCQ significantly inhibits the proliferation of rat lung fibroblasts, regulates inflammation and ameliorates bleomycin-induced pulmonary fibrosis in rats. It regulates the expression of pro-inflammatory cytokines, such as TNF-α; reduces the infiltration of inflammatory neutrophils; and inhibits the phosphorylation of NF-κB. Chol-HCQ also reduces the expression of connective tissue growth factor (CTGF) and phosphorylation of extracellular regulated protein kinase (p-ERK) in rats with bleomycin-induced pulmonary fibrosis. Chol-HCQ nanocarriers reduce early pulmonary inflammation and inhibit the CTGF/ERK signalling pathway in bleomycin-induced pulmonary fibrosis. These results demonstrate that Chol-HCQ liposomes suppress pulmonary inflammation and reduce pulmonary fibrosis induced by bleomycin. The systemic administration safety of Chol-HCQ liposomes was confirmed after intravenous administration for 28 days in rats. The present study provides evidence that Chol-HCQ liposomes may be a potential therapeutic agent for inflammation associated with pulmonary fibrosis.

Idiopathic Pulmonary Fibrosis: The Association between the Adaptive Multiple Features Method and Fibrosis Outcomes

RATIONALE

Adaptive multiple features method (AMFM) lung texture analysis software recognizes high-resolution computed tomography (HRCT) patterns.

OBJECTIVES

To evaluate AMFM and visual quantification of HRCT patterns and their relationship with disease progression in idiopathic pulmonary fibrosis.

METHODS

Patients with idiopathic pulmonary fibrosis in a clinical trial of prednisone, azathioprine, and N-acetylcysteine underwent HRCT at study start and finish. Proportion of lung occupied by ground glass, ground glass-reticular (GGR), honeycombing, emphysema, and normal lung densities were measured by AMFM and three radiologists, documenting baseline disease extent and postbaseline change. Disease progression includes composite mortality, hospitalization, and 10% FVC decline.

MEASUREMENTS AND MAIN RESULTS

Agreement between visual and AMFM measurements was moderate for GGR (Pearson's correlation r = 0.60, P < 0.0001; mean difference = -0.03 with 95% limits of agreement of -0.19 to 0.14). Baseline extent of GGR was independently associated with disease progression when adjusting for baseline Gender-Age-Physiology stage and smoking status (hazard ratio per 10% visual GGR increase = 1.98, 95% confidence interval [CI] = 1.20-3.28, P = 0.008; and hazard ratio per 10% AMFM GGR increase = 1.36, 95% CI = 1.01-1.84, P = 0.04). Postbaseline visual and AMFM GGR trajectories were correlated with postbaseline FVC trajectory (r = -0.30, 95% CI = -0.46 to -0.11, P = 0.002; and r = -0.25, 95% CI = -0.42 to -0.06, P = 0.01, respectively).

CONCLUSIONS

More extensive baseline visual and AMFM fibrosis (as measured by GGR densities) is independently associated with elevated hazard for disease progression. Postbaseline change in AMFM-measured and visually measured GGR densities are modestly correlated with change in FVC. AMFM-measured fibrosis is an automated adjunct to existing prognostic markers and may allow for study enrichment with subjects at increased disease progression risk.

Fibroblast paracrine TNF-α signaling elevates integrin A5 expression in idiopathic pulmonary fibrosis (IPF)

Background

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a poor prognosis. Inflammatory cytokines play a significant role in IPF pathology. However, the fibroblast itself is also believed to be the primary effector in IPF. We hypothesized that the fibroblasts themselves secrete pro-inflammatory cytokines that could propagate IPF by affecting normal neighboring cells. Thus, we explored the effects of IPF fibroblast derived media on normal fibroblast characteristics.

Methods

Primary IPF/normal tissue derived fibroblast cultures were established and their supernatants were collected (IPF/N-SN, respectively). These supernatants were added to normal fibroblasts. Cell death (caspase-3, western blot), proliferation, viability (WST-1), migration (scratch test) and cell detachment (crystal violet and fibronectin adhesion assays) were tested. 10 inflammatory cytokines were measured by ELISA-based quantitative array. Integrin α5 (ITGA5), pIκBα, p/total STAT3 levels were measured by western blot/IHC. TNF-α involvement was confirmed using Infliximab ®, anti-TNF-α mAb.

Results

The IPF-SN facilitated fibroblast cell detachment and reduced cell migration (p < 0.05). Nevertheless, these effects were reversed when cells were seeded on fibronectin. The exposure to the IPF-SN also elevated ITGA5 levels, the fibronectin receptor, in addition to NFκB pathway activation (pIκBα↑ 150%, p < 0.05). In accordance, IPF derived fibroblasts were found to express higher ITGA5 than the normal cells (44%↑, p < 0.05). ITGA5 was also expressed in the fibroblastic foci.

The IPF-SN contained high TNF-α levels (3-fold, p < 0.05), and Infliximab pretreatment successfully reversed all the above observations.

Conclusion

We suggest a possible mechanism in which IPF fibroblast secreted TNF-α modifies neighboring fibroblast cell behavior.