Corticosteroids for idiopathic pulmonary fibrosis

NLRP3 inflammasome activation contributes to the development of the pro-fibrotic phenotype of lung fibroblasts

Idiopathic pulmonary fibrosis (IPF) is an irreversible progressive interstitial lung disease of unknown cause. The poorly understood pathophysiology of IPF poses substantial challenges to the development of effective anti-lung fibrotic drugs. The NLRP3 inflammasome, a key component of the innate immune system, has recently been linked to the pathogenesis of lung fibrosis. However, the specific contributions of NLRP3 inflammasomes to determination of the pro-fibrotic phenotype of lung fibroblasts, which play a central role in the production of extracellular matrix protein, remain to be investigated. Therefore, the present study was performed to elucidate the involvement of NLRP3 inflammasome signalling pathways in modulation of lung fibroblast proliferation and differentiation. We found that activation of NLRP3 inflammasomes increased in lung fibroblasts derived from individuals with pulmonary fibrosis and in normal lung fibroblasts stimulated with transforming growth factor β and platelet-derived growth factor. Importantly, blockage of NLRP3 inflammasome signalling, either by gene silencing of NLRP3 or using pharmacological inhibitors of NLRP3, caspase-1, or IL-1 receptor, inhibited the proliferation, differentiation, and extracellular matrix protein synthesis of activated lung fibroblasts. Moreover, induction of the reactive oxygen species/thioredoxin-interacting protein axis, an upstream signalling pathway of NLRP3 inflammasomes, was essential for maintenance of the pro-fibrotic phenotype of lung fibroblasts. Interestingly, treatments with pharmacological inhibitors of NLRP3 inflammasomes prevented the progression of bleomycin-induced pulmonary fibrosis in mice. Collectively, these findings suggest that aberrant activation of NLRP3 inflammasomes is a critical event in the pathogenesis of IPF and that targeting NLRP3 inflammasomes may serve as a therapeutic strategy for IPF.

Emerging pharmacological options in the treatment of idiopathic pulmonary fibrosis (IPF)

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a progressive-fibrosing lung disease with a median survival of less than 5 years. Currently, two agents, pirfenidone and nintedanib are approved for this disease, and both have been shown to reduce the rate of decline in lung function in patients with IPF. However, both have significant adverse effects and neither completely arrest the decline in lung function.

AREAS COVERED

Thirty experimental agents with unique mechanisms of action that are being evaluated for the treatment of IPF are discussed. These agents work through various mechanisms of action, these include inhibition of transcription nuclear factor k-B on fibroblasts, reduced expression of metalloproteinase 7, the generation of more lysophosphatidic acids, blocking the effects of transforming growth factor ß, and reducing reactive oxygen species as examples of some unique mechanisms of action of these agents.

EXPERT OPINION

New drug development has the potential to expand the treatment options available in the treatment of IPF patients. It is expected that the adverse drug effect profiles will be more favorable than current agents. It is further anticipated that these new agents or combinations of agents will arrest the fibrosis, not just slow the fibrotic process.

Cellular therapies for idiopathic pulmonary fibrosis: current progress and future prospects

Idiopathic pulmonary fibrosis (IPF) is an interstitial, fibrotic lung disease characterized by progressive damage. Lung tissues with IPF are replaced by fibrotic tissues with increased collagen deposition, modified extracellular matrix, all which overall damages the alveoli. These changes eventually impede the gas exchange function of the alveoli, and eventually leads to fatal respiratory failure of the lung. Investigations have been conducted to further understand IPF's pathogenesis, and significant progress in understanding its development has been made. Additionally, two therapeutic treatments, Nintedanib and Pirfenidone, have been approved and are currently used in medical applications. Moreover, cell-based treatments have recently come to the forefront of developing disease therapeutics and are the focus of many current studies. Furthermore, a sizable body of research encompassing basic, pre-clinical, and even clinical trials have all been amassed in recent years and hold a great potential for more widespread applications in patient care. Herein, this article reviews the progress in understanding the pathogenesis and pathophysiology of IPF. Additionally, different cell types used in IPF therapy were reviewed, including alveolar epithelial cells (AECs), circulating endothelial progenitors (EPCs), mixed lung epithelial cells, different types of stem cells, and endogenous lung tissue-specific stem cells. Finally, we discussed the contemporary trials that employ or explore cell-based therapy for IPF.

Stem cell-based therapy for fibrotic diseases: mechanisms and pathways

Fibrosis is a pathological process, that could result in permanent scarring and impairment of the physiological function of the affected organ; this condition which is categorized under the term organ failure could affect various organs in different situations. The involvement of the major organs, such as the lungs, liver, kidney, heart, and skin, is associated with a high rate of morbidity and mortality across the world. Fibrotic disorders encompass a broad range of complications and could be traced to various illnesses and impairments; these could range from simple skin scars with beauty issues to severe rheumatologic or inflammatory disorders such as systemic sclerosis as well as idiopathic pulmonary fibrosis. Besides, the overactivation of immune responses during any inflammatory condition causing tissue damage could contribute to the pathogenic fibrotic events accompanying the healing response; for instance, the inflammation resulting from tissue engraftment could cause the formation of fibrotic scars in the grafted tissue, even in cases where the immune system deals with hard to clear infections, fibrotic scars could follow and cause severe adverse effects. A good example of such a complication is post-Covid19 lung fibrosis which could impair the life of the affected individuals with extensive lung involvement. However, effective therapies that halt or slow down the progression of fibrosis are missing in the current clinical settings. Considering the immunomodulatory and regenerative potential of distinct stem cell types, their application as an anti-fibrotic agent, capable of attenuating tissue fibrosis has been investigated by many researchers. Although the majority of the studies addressing the anti-fibrotic effects of stem cells indicated their potent capabilities, the underlying mechanisms, and pathways by which these cells could impact fibrotic processes remain poorly understood. Here, we first, review the properties of various stem cell types utilized so far as anti-fibrotic treatments and discuss the challenges and limitations associated with their applications in clinical settings; then, we will summarize the general and organ-specific mechanisms and pathways contributing to tissue fibrosis; finally, we will describe the mechanisms and pathways considered to be employed by distinct stem cell types for exerting anti-fibrotic events.

Triamcinolone acetonide alleviates benign biliary stricture by ameliorating biliary fibrosis and inflammation

We conducted a comprehensive series of molecular biological studies aimed at unraveling the intricate mechanisms underlying the anti-fibrotic effects of triamcinolone acetonide (TA) when used in conjunction with fully covered self-expandable metal stents (FCSEMS) for the management of benign biliary strictures (BBS). To decipher the molecular mechanisms responsible for the anti-fibrotic effects of corticosteroids on gallbladder mucosa, we conducted a comprehensive analysis. This analysis included various methodologies such as immunohistochemistry, ELISA, real-time PCR, and transcriptome analysis, enabling us to examine alterations in factors related to fibrosis and inflammation at both the protein and RNA levels. Overall, our findings revealed a dose-dependent decrease in fibrosisrelated signaling with higher TA concentrations. The 15 mg of steroid treatment (1X) exhibited anti-fibrosis and anti-inflammatory effects after 4 weeks, whereas the 30 mg of steroid treatment (2X) rapidly reduced fibrosis and inflammation within 2 weeks in BBS. Transcriptomic analysis results consistently demonstrated significant downregulation of fibrosis- and inflammation-related pathways and genes in steroid-treated fibroblasts. Use of corticosteroids, specifically TA, together with FCSEMS was effective for the treatment of BBS, ameliorating fibrosis and inflammation. Our molecular biological analysis supports the potential development of steroid-eluted FCSEMS as a therapeutic option for BBS in humans resulting from various surgical procedures. [BMB Reports 2024; 57(4): 200-205].

Systemic corticosteroids in fibrotic lung disease: a systematic review and meta-analysis

OBJECTIVES

We aimed to assess the available evidence for corticosteroids in fibrotic interstitial lung disease (fILD) to inform the randomised embedded multifactorial adaptive platform ILD.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched Embase, Medline, Cochrane CENTRAL and Web of Science databases from inception to April 17 2023.

ELIGIBILITY CRITERIA

We included studies that compared corticosteroids with standard care, placebo or no treatment in adult patients with fILD.

DATA EXTRACTION AND SYNTHESIS

We report on the change in forced vital capacity (FVC) and mortality. We used random-effects meta-analysis to estimate relative risk (RR) for dichotomous outcomes, and mean difference (MD) and standardised MDs for continuous outcomes, with 95% CIs.

RESULTS

Of the 13 229 unique citations identified, we included 10 observational studies comprising 1639 patients. Corticosteroids had an uncertain effect on mortality compared with no treatment (RR 1.03 (95% CI 0.85 to 1.25); very low certainty evidence). The effect of corticosteroids on the rate of decline in FVC (% predicted) was uncertain when compared with no treatment (MD 4.29% (95% CI -8.26% to 16.83%); very low certainty evidence). However, corticosteroids might reduce the rate of decline in FVC in patients with non-idiopathic pulmonary fibrosis (IPF) fILD (MD 10.89% (95% CI 5.25% to 16.53%); low certainty evidence), while an uncertain effect was observed in patients with IPF (MD -3.80% (95% CI -8.94% to 1.34%); very low certainty evidence).

CONCLUSIONS

The current evidence on the efficacy and safety of corticosteroids in fILD is limited and of low certainty. Randomised trials are needed to address this significant research gap.

Genetic Programs Between Steroid-Sensitive and Steroid-Insensitive Interstitial Lung Disease

The effectiveness of corticosteroids (GCs) varies greatly in interstitial lung diseases (ILDs). In this study, we aimed to compare the gene expression profiles of patients with cryptogenic organizing pneumonia (COP), idiopathic pulmonary fibrosis (IPF), and non-specific interstitial pneumonia (NSIP) and identify the molecules and pathways responsible for GCs sensitivity in ILDs. Three datasets (GSE21411, GSE47460, and GSE32537) were selected. Differentially expressed genes (DEGs) among COP, IPF, NSIP, and healthy control (CTRL) groups were identified. Functional enrichment analysis and protein-protein interaction network analysis were performed to examine the potential functions of DEGs. There were 128 DEGs when COP versus CTRL, 257 DEGs when IPF versus CTRL, 205 DEGs when NSIP versus CTRL, and 270 DEGs when COP versus IPF. The DEGs in different ILDs groups were mainly enriched in the inflammatory response. Further pathway analysis showed that "interleukin (IL)-17 signaling pathway" (hsa04657) and "tumor necrosis factor (TNF) signaling pathway" were associated with different types of ILDs. A total of 10 genes associated with inflammatory response were identified as hub genes and their expression levels in the IPF group were higher than those in the COP group. Finally, we identified two GCs' response-related differently expressed genes (FOSL1 and DDIT4). Our bioinformatics analysis demonstrated that the inflammatory response played a pathogenic role in the progression of ILDs. We also illustrated that the inflammatory reaction was more severe in the IPF group compared to the COP group and identified two GCs' response-related differently expressed genes (FOSL1 and DDIT4) in ILDs.

In vitro co-culture studies and the crucial role of fibroblast-immune cell crosstalk in IPF pathogenesis

IPF is a fatal lung disease characterized by intensive remodeling of lung tissue leading to respiratory failure. The remodeling in IPF lungs is largely characterized by uncontrolled fibrosis. Fibroblasts and their contractile phenotype the myofibroblast are the main cell types responsible for typical wound healing responses, however in IPF, these responses are aberrant and result in the overactivation of fibroblasts which contributes to the inelasticity of the lung leading to a decrease in lung function. The specific mechanisms behind IPF pathogenesis have been elusive, but recently the innate and adaptive immunity have been implicated in the fibrotic processes of the disease. In connection with this, several in vitro co-culture models have been used to investigate the specific interactions occurring between fibroblasts and immune cells and how this contributes to the pathobiology of IPF. In this review, we discuss the in vitro models that have been used to examine the abnormal interactions between fibroblasts and cells of the innate and adaptive immune system, and how these contribute to the fibrotic processes in the lungs of IPF patients.

Pulmonary inflammation and fibroblast immunoregulation: from bench to bedside

In recent years, there has been an explosion of interest in how fibroblasts initiate, sustain, and resolve inflammation across disease states. Fibroblasts contain heterogeneous subsets with diverse functionality. The phenotypes of these populations vary depending on their spatial distribution within the tissue and the immunopathologic cues contributing to disease progression. In addition to their roles in structurally supporting organs and remodeling tissue, fibroblasts mediate critical interactions with diverse immune cells. These interactions have important implications for defining mechanisms of disease and identifying potential therapeutic targets. Fibroblasts in the respiratory tract, in particular, determine the severity and outcome of numerous acute and chronic lung diseases, including asthma, chronic obstructive pulmonary disease, acute respiratory distress syndrome, and idiopathic pulmonary fibrosis. Here, we review recent studies defining the spatiotemporal identity of the lung-derived fibroblasts and the mechanisms by which these subsets regulate immune responses to insult exposures and highlight past, current, and future therapeutic targets with relevance to fibroblast biology in the context of acute and chronic human respiratory diseases. This perspective highlights the importance of tissue context in defining fibroblast-immune crosstalk and paves the way for identifying therapeutic approaches to benefit patients with acute and chronic pulmonary disorders.

Immune Mechanisms of Pulmonary Fibrosis with Bleomycin

Fibrosis and structural remodeling of the lung tissue can significantly impair lung function, often with fatal consequences. The etiology of pulmonary fibrosis (PF) is diverse and includes different triggers such as allergens, chemicals, radiation, and environmental particles. However, the cause of idiopathic PF (IPF), one of the most common forms of PF, remains unknown. Experimental models have been developed to study the mechanisms of PF, and the murine bleomycin (BLM) model has received the most attention. Epithelial injury, inflammation, epithelial-mesenchymal transition (EMT), myofibroblast activation, and repeated tissue injury are important initiators of fibrosis. In this review, we examined the common mechanisms of lung wound-healing responses after BLM-induced lung injury as well as the pathogenesis of the most common PF. A three-stage model of wound repair involving injury, inflammation, and repair is outlined. Dysregulation of one or more of these three phases has been reported in many cases of PF. We reviewed the literature investigating PF pathogenesis, and the role of cytokines, chemokines, growth factors, and matrix feeding in an animal model of BLM-induced PF.

The novel role of ER protein TXNDC5 in the pathogenesis of organ fibrosis: mechanistic insights and therapeutic implications

Fibrosis-related disorders account for an enormous burden of disease-associated morbidity and mortality worldwide. Fibrosis is defined by excessive extracellular matrix deposition at fibrotic foci in the organ tissue following injury, resulting in abnormal architecture, impaired function and ultimately, organ failure. To date, there lacks effective pharmacological therapy to target fibrosis per se, highlighting the urgent need to identify novel drug targets against organ fibrosis. Recently, we have discovered the critical role of a fibroblasts-enriched endoplasmic reticulum protein disulfide isomerase (PDI), thioredoxin domain containing 5 (TXNDC5), in cardiac, pulmonary, renal and liver fibrosis, showing TXNDC5 is required for the activation of fibrogenic transforming growth factor-β signaling cascades depending on its catalytic activity as a PDI. Moreover, deletion of TXNDC5 in fibroblasts ameliorates organ fibrosis and preserves organ function by inhibiting myofibroblasts activation, proliferation and extracellular matrix production. In this review, we detailed the molecular and cellular mechanisms by which TXNDC5 promotes fibrogenesis in various tissue types and summarized potential therapeutic strategies targeting TXNDC5 to treat organ fibrosis.

Immunophenotyping of Acute Inflammatory Exacerbations of Lung Injury Driven by Mutant Surfactant Protein-C: A Role for Inflammatory Eosinophils

Acute inflammatory exacerbations (AIEs) represent immune-driven deteriorations of many chronic lung conditions, including COPD, asthma, and pulmonary fibrosis (PF). The first line of therapy is represented by broad-spectrum immunomodulation. Among the several inflammatory populations mobilizing during AIEs, eosinophils have been identified as promising indicators of an active inflammatory exacerbation. To better study the eosinophil-parenchymal crosstalk during AIE-PF, this work leverages a clinically relevant model of inflammatory exacerbations triggered by inducible expression of a mutation in the alveolar epithelial type 2 cell Surfactant Protein-C gene [SP-C^I73T]. Unbiased single-cell sequencing analysis of controls and SP-C^I73T mutants at a time coordinated with peak eosinophilia (14 days) defined heightened inflammatory activation, chemotaxis, and survival signaling (IL-6, IL-4/13, STAT3, Glucocorticoid Receptor, mTOR, and MYC) in eosinophils. To study the impact of eosinophils in inflammatory exacerbations, the SP-C^I73T line was crossed with eosinophil lineage deficient mice (GATA1^Δdbl) to produce the SP-C^I73TGATA1^KO line. Time course analysis (7-42 days) demonstrated improved lung histology, survival, and reduced inflammation in SP-C^I73TGATA1^KO cohorts. Spectral flow cytometry of tissue digests confirmed eosinophil depletion in GATA1^KO mice and the absence of a compensatory shift in neutrophils and immature monocyte recruitment. Eosinophil deletion resulted in progressive monocyte-derived macrophage accumulation (14 days post-injury), combined with declines in CD3⁺CD4⁺ lymphocyte and B220⁺ B cell abundance. Histochemical analysis revealed atypical inflammatory cell activation in SP-C^I73TGATA1^KO mice, with reduced numbers of Arg-1⁺ and iNOS⁺ cells, but increases in tgfb1 mRNA expression in bronchoalveolar lavage cells and tissue. Dexamethasone treatment (1 mg/kg daily, i.p.) was utilized to investigate corticosteroid efficacy in highly eosinophilic exacerbations induced by mutant SP-C^I73T. Dexamethasone successfully reduced total and eosinophil (CD11b⁺SigF⁺CD11c^-) counts at 14 days and was linked to reduced evidence of structural damage and perivascular infiltrate. Together, these results illustrate the deleterious role of eosinophils in inflammatory events preceding lung fibrosis and demonstrate the efficacy of corticosteroid treatment in highly eosinophilic exacerbations induced by mutant SP-C^I73T.

Targeting Chitinase 1 and Chitinase 3-Like 1 as Novel Therapeutic Strategy of Pulmonary Fibrosis

Chitinase 1 (CHIT1) and chitinase 3-like-1 (CHI3L1), two representative members of 18-Glycosyl hydrolases family, are significantly implicated in the pathogenesis of various human diseases characterized by inflammation and remodeling. Notably, dysregulated expression of CHIT1 and CHI3L1 was noted in the patients with pulmonary fibrosis and their levels were inversely correlated with clinical outcome of the patients. CHIT1 and CHI3L1, mainly expressed in alveolar macrophages, regulate profibrotic macrophage activation, fibroblast proliferation and myofibroblast transformation, and TGF-β signaling and effector function. Although the mechanism or the pathways that CHIT1 and CHI3L1 use to regulate pulmonary fibrosis have not been fully understood yet, these studies identify CHIT1 and CHI3L1 as significant modulators of fibroproliferative responses leading to persistent and progressive pulmonary fibrosis. These studies suggest a possibility that CHIT1 and CHI3L1 could be reasonable therapeutic targets to intervene or reverse established pulmonary fibrosis. In this review, we will discuss specific roles and regulatory mechanisms of CHIT1 and CHI3L1 in profibrotic cell and tissue responses as novel therapeutic targets of pulmonary fibrosis.

A review on importance of bioactive compounds of medicinal plants in treating idiopathic pulmonary fibrosis (special emphasis on isoquinoline alkaloids)

Background

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease of unknown cause which disrupts the normal lung architecture and functions by deregulating immune responses and ultimately leads to the death of the individual. A number of factors can lead to its development and currently there is no cure for this disease.

Main text

There are synthetic drugs available to relieve the symptoms and decelerate its development by targeting pathways involved in the development of IPF, but there had also been various side effects detected by their usage. It is known since decades that medicinal plants and their compounds have been used all over the world in natural medicines to cure various diseases. This review article is focused on the effects of various natural bioactive compounds of 26 plant extracts that show prophylactic and therapeutic properties against the disease and so can be used in treating IPF replacing synthetic drugs and reducing the side effects.

Short conclusion

This review includes different mechanisms that cause pulmonary fibrosis along with compounds that can induce fibrosis, drugs used for the treatment of pulmonary fibrosis, diagnosis, the biochemical tests used for the experimental study to determine the pathogenesis of disease with a special note on Isoquinoline alkaloids and their role in reducing various factors leading to IPF thus providing promising therapeutic approach.

Therapeutic and diagnostic targeting of fibrosis in metabolic, proliferative and viral disorders

Fibrosis is a common denominator in many pathologies and crucially affects disease progression, drug delivery efficiency and therapy outcome. We here summarize therapeutic and diagnostic strategies for fibrosis targeting in atherosclerosis and cardiac disease, cancer, diabetes, liver diseases and viral infections. We address various anti-fibrotic targets, ranging from cells and genes to metabolites and proteins, primarily focusing on fibrosis-promoting features that are conserved among the different diseases. We discuss how anti-fibrotic therapies have progressed over the years, and how nanomedicine formulations can potentiate anti-fibrotic treatment efficacy. From a diagnostic point of view, we discuss how medical imaging can be employed to facilitate the diagnosis, staging and treatment monitoring of fibrotic disorders. Altogether, this comprehensive overview serves as a basis for developing individualized and improved treatment strategies for patients suffering from fibrosis-associated pathologies.

The Epithelial-Immune Crosstalk in Pulmonary Fibrosis

Interactions between the lung epithelium and the immune system involve a tight regulation to prevent inappropriate reactions and have been connected to several pulmonary diseases. Although the distal lung epithelium and local immunity have been implicated in the pathogenesis and disease course of idiopathic pulmonary fibrosis (IPF), consequences of their abnormal interplay remain less well known. Recent data suggests a two-way process, as illustrated by the influence of epithelial-derived periplakin on the immune landscape or the effect of macrophage-derived IL-17B on epithelial cells. Additionally, damage associated molecular patterns (DAMPs), released by damaged or dying (epithelial) cells, are augmented in IPF. Next to “sterile inflammation”, pathogen-associated molecular patterns (PAMPs) are increased in IPF and have been linked with lung fibrosis, while outer membrane vesicles from bacteria are able to influence epithelial-macrophage crosstalk. Finally, the advent of high-throughput technologies such as microbiome-sequencing has allowed for the identification of a disease-specific microbial environment. In this review, we propose to discuss how the interplays between the altered distal airway and alveolar epithelium, the lung microbiome and immune cells may shape a pro-fibrotic environment. More specifically, it will highlight DAMPs-PAMPs pathways and the specificities of the IPF lung microbiome while discussing recent elements suggesting abnormal mucosal immunity in pulmonary fibrosis.

Spontaneous Lung Fibrosis Resolution Reveals Novel Antifibrotic Regulators

Fibroblast activation is transient in successful wound repair but persistent in fibrotic pathologies. Understanding fibroblast deactivation during successful wound healing may provide new approaches to therapeutically reverse fibroblast activation. To characterize the gene programs that accompany fibroblast activation and reversal during lung fibrosis resolution, we used RNA sequencing analysis of flow sorted Col1α1-GFP-positive and CD45-, CD31-, and CD326-negative cells isolated from the lungs of young mice exposed to bleomycin. We compared fibroblasts isolated from control mice with those isolated at Days 14 and 30 after bleomycin exposure, representing the peak of extracellular matrix deposition and an early stage of fibrosis resolution, respectively. Bleomycin exposure dramatically altered fibroblast gene programs at Day 14. Principal component and differential gene expression analyses demonstrated the predominant reversal of these trends at Day 30. Upstream regulator and pathway analyses of reversing "resolution" genes identified novel candidate antifibrotic genes and pathways. Two genes from these analyses that were decreased in expression at Day 14 and reversed at Day 30, Aldh2 and Nr3c1, were selected for further analysis. Enhancement of endogenous expression of either gene by CRISPR activation in cultured human idiopathic pulmonary fibrosis fibroblasts was sufficient to reduce profibrotic gene expression, fibronectin deposition, and collagen gel compaction, consistent with roles for these genes in fibroblast deactivation. This combination of RNA sequencing analysis of freshly sorted fibroblasts and hypothesis testing in cultured idiopathic pulmonary fibrosis fibroblasts offers a path toward identification of novel regulators of lung fibroblast deactivation, with potential relevance to understanding fibrosis resolution and its failure in human disease.

Role of CCR2+ Myeloid Cells in Inflammation Responses Driven by Expression of a Surfactant Protein-C Mutant in the Alveolar Epithelium

Acute inflammatory exacerbations (AIE) represent precipitous deteriorations of a number of chronic lung conditions, including pulmonary fibrosis (PF), chronic obstructive pulmonary disease and asthma. AIEs are marked by diffuse and persistent polycellular alveolitis that profoundly accelerate lung function decline and mortality. In particular, excess monocyte mobilization during AIE and their persistence in the lung have been linked to poor disease outcome. The etiology of AIEs remains quite uncertain, but environmental exposure and genetic predisposition/mutations have been identified as two contributing factors. Guided by clinical evidence, we have developed a mutant model of pulmonary fibrosis leveraging the PF-linked missense isoleucine to threonine substitution at position 73 [I73T] in the alveolar type-2 cell-restricted Surfactant Protein-C [SP-C] gene [SFTPC]. With this toolbox at hand, the present work investigates the role of peripheral monocytes during the initiation and progression of AIE-PF. Genetic ablation of CCR2⁺ monocytes (SP-C^I73TCCR2^KO) resulted in improved lung histology, mouse survival, and reduced inflammation compared to SP-C^I73TCCR2^WT cohorts. FACS analysis of CD11b⁺CD64^-Ly6C^hi monocytes isolated 3 d and 14 d after SP-C^I73T induced injury reveals dynamic transcriptional changes associated with “Innate Immunity’ and ‘Extracellular Matrix Organization’ signaling. While immunohistochemical and in situ hybridization analysis revealed comparable levels of tgfb1 mRNA expression localized primarily in parenchymal cells found nearby foci of injury we found reduced effector cell activation (C1q, iNOS, Arg1) in SP-C^I73TCCR2^KO lungs as well as partial colocalization of tgfb1 mRNA expression in Arg1⁺ cells. These results provide a detailed picture of the role of resident macrophages and recruited monocytes in the context of AIE-PF driven by alveolar epithelial dysfunction.

Nintedanib and immunomodulatory therapies in progressive fibrosing interstitial lung diseases

Background

In the INBUILD trial in patients with chronic fibrosing interstitial lung diseases (ILDs) and a progressive phenotype, nintedanib reduced the rate of ILD progression with adverse events that were manageable for most patients. We investigated the potential impact of immunomodulatory therapies on the efficacy and safety of nintedanib.

Methods

Subjects with fibrosing ILDs other than idiopathic pulmonary fibrosis, who had shown progression of ILD within the prior 24 months despite management in clinical practice, were randomized to receive nintedanib or placebo. Certain immunomodulatory therapies were restricted for the first 6 months. We analyzed post-hoc the rate of decline in forced vital capacity (FVC) over 52 weeks in subgroups by glucocorticoid use at baseline and in analyses excluding subjects or FVC measurements taken after initiation of restricted immunomodulatory or antifibrotic therapies.

Results

Of 663 subjects, 361 (54.4%) were taking glucocorticoids at baseline (353 at a dose of ≤ 20 mg/day). In the placebo group, the adjusted rate of decline in FVC (mL/year) over 52 weeks was numerically greater in subjects taking than not taking glucocorticoids at baseline (− 206.4 [SE 20.2] vs − 165.8 [21.9]). The difference between the nintedanib and placebo groups was 133.3 (95% CI 76.6, 190.0) mL/year in subjects taking glucocorticoids at baseline and 76.1 (15.0, 137.2) mL/year in subjects who were not (interaction P = 0.18). The effect of nintedanib on reducing the rate of FVC decline in analyses excluding subjects or measurements taken after initiation of restricted immunomodulatory or antifibrotic therapies was similar to the primary analysis. The adverse event profile of nintedanib was similar between subjects who did and did not use prohibited or restricted therapies at baseline or during treatment with trial drug.

Conclusions

In patients with progressive fibrosing ILDs, the effect of nintedanib on reducing FVC decline was not influenced by the use of immunomodulatory therapies. Nintedanib can be used in combination with immunomodulatory therapies in patients with progressive fibrosing ILDs.

Trial registration ClinicalTrials.gov, NCT02999178. Registered 21 December 2016, https://clinicaltrials.gov/ct2/show/NCT02999178

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01668-1.

Airway Redox Homeostasis and Inflammation Gone Awry: From Molecular Pathogenesis to Emerging Therapeutics in Respiratory Pathology

As aerobic organisms, we are continuously and throughout our lifetime subjected to an oxidizing atmosphere and, most often, to environmental threats. The lung is the internal organ most highly exposed to this milieu. Therefore, it has evolved to confront both oxidative stress induced by reactive oxygen species (ROS) and a variety of pollutants, pathogens, and allergens that promote inflammation and can harm the airways to different degrees. Indeed, an excess of ROS, generated intrinsically or from external sources, can imprint direct damage to key structural cell components (nucleic acids, sugars, lipids, and proteins) and indirectly perturb ROS-mediated signaling in lung epithelia, impairing its homeostasis. These early events complemented with efficient recognition of pathogen- or damage-associated recognition patterns by the airway resident cells alert the immune system, which mounts an inflammatory response to remove the hazards, including collateral dead cells and cellular debris, in an attempt to return to homeostatic conditions. Thus, any major or chronic dysregulation of the redox balance, the air-liquid interface, or defects in epithelial proteins impairing mucociliary clearance or other defense systems may lead to airway damage. Here, we review our understanding of the key role of oxidative stress and inflammation in respiratory pathology, and extensively report current and future trends in antioxidant and anti-inflammatory treatments focusing on the following major acute and chronic lung diseases: acute lung injury/respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and cystic fibrosis.

Idiopathic Pulmonary Fibrosis: Pathogenesis and the Emerging Role of Long Non-Coding RNAs

Idiopathic pulmonary fibrosis (IPF) is a progressive chronic disease characterized by excessing scarring of the lungs leading to irreversible decline in lung function. The aetiology and pathogenesis of the disease are still unclear, although lung fibroblast and epithelial cell activation, as well as the secretion of fibrotic and inflammatory mediators, have been strongly associated with the development and progression of IPF. Significantly, long non-coding RNAs (lncRNAs) are emerging as modulators of multiple biological processes, although their function and mechanism of action in IPF is poorly understood. LncRNAs have been shown to be important regulators of several diseases and their aberrant expression has been linked to the pathophysiology of fibrosis including IPF. This review will provide an overview of this emerging role of lncRNAs in the development of IPF.

Retrospective immunohistological study of autopsied lungs in patients with acute exacerbation of interstitial pneumonia managed with extracorporeal membrane oxygenation

Background

Acute exacerbation of interstitial pneumonia (AE-IP) is a life-threatening pulmonary condition that involves various pathogeneses. In patients with AE-IP who need mechanical ventilation with high driving pressure and oxygen concentration, veno-venous extracorporeal membrane oxygenation (V-V ECMO) may diminish alveolar epithelial damage by decreasing ventilator settings. The pathophysiological benefit of this therapeutic option is not well investigated.

Methods

We retrospectively collected 15 autopsied patients with AE-IP who were treated with mechanical ventilation in the intensive care unit (ICU) at Hiroshima University Hospital (Hiroshima, Japan) between 2010 and 2016. The patients were grouped by whether they were managed with mechanical ventilation only (the ventilator group, n=6) or with mechanical ventilation and V-V ECMO (the ECMO group, n=9).

Results

The median age of the ventilator and ECMO group patients were similar (65 and 64 years, respectively). The severity score APACHE II in the ECMO group (35.0) is significantly higher than that of ventilator group (14.5) (P=0.006). Ventilator days were significantly shorter in the ventilator group (17.5 days) than in the ECMO group (30.0 days) (P=0.04). Compared with the ECMO group, the ventilator group had a stronger Masson-trichrome stain grade (4 vs. 6, P=0.04) and higher immunoreactivity grades for Krebs von den Lungen-6 (4 vs. 6, P=0.04) and IL-8 (3 vs. 6, P=0.02). Between the ventilator and ECMO groups, the immunoreactivity grades of angiopoietin 2 (4 vs. 1, P=0.08) and receptor for advanced glycation end products (2 vs. 1, P=0.52) did not differ.

Conclusions

The lungs of mechanically ventilated AE-IP patients treated with V-V ECMO had decreased fibrosis, endothelial injury, and inflammation. This finding suggests the lung-protective efficacy of adjunctive V-V ECMO therapy.

Elevation of IL-6 and IL-33 Levels in Serum Associated with Lung Fibrosis and Skeletal Muscle Wasting in a Bleomycin-Induced Lung Injury Mouse Model

Weight loss due to skeletal muscle atrophy in patients with chronic pulmonary disease is negatively correlated with clinical outcome. Pulmonary fibrosis is a chronic and progressive interstitial lung disease characterized by the dysregulated deposition of the extracellular matrix (ECM) with the destruction of normal tissue, resulting in end-stage organ failure. BLM-induced fibrosis is one of several different experimental models of pulmonary fibrosis, characterized by inflammation and excessive ECM deposition. We directly induced mouse lung injury by the intratracheal administration of bleomycin and monitored the physiological and biochemical changes in lung and skeletal muscle tissues by using lung function testing, ELISA, Western blotting, and immunohistochemistry. Here, we found that BLM-induced lung fibrosis with thickened interstitial lung tissue, including fibronectin and collagen, was correlated with the increased serum concentrations of IL-6 and IL-33 and accompanied by reduced lung function, including FRC (functional residual capacity), C chord (lung compliance), IC (inspiratory capacity), VC (vital capacity), TLC (total lung capacity), and FVC (forced vital capacity) (p < 0.05). The activity of AKT in lung tissue was suppressed, but conversely, the activity of STAT3 was enhanced during lung fibrosis in mice. In addition, we found that the amount of sST2, the soluble form of the IL-33 receptor, was dramatically decreased in lung fibrosis tissues. The skeletal muscle tissue isolated from lung injury mice increased the activation of STAT3 and AMPK, accompanied by an increased amount of Atrogin-1 protein in BLM-induced lung fibrosis mice. The mouse myoblast cell-based model showed that IL-6 and IL-33 specifically activated STAT3 and AMPK signaling, respectively, to induce the expression of the muscle-specific proteolysis markers MuRF1 and Atrogin-1. These data suggested that increased levels of IL-6 and IL-33 in the serum of mice with BLM-induced lung injury may cause lung fibrosis with thickened interstitial lung tissue accompanied by reduced lung function and muscle mass through the activation of STAT3 and AMPK signals.

Epithelial Expression of an Interstitial Lung Disease-Associated Mutation in Surfactant Protein-C Modulates Recruitment and Activation of Key Myeloid Cell Populations in Mice

Patients with idiopathic pulmonary fibrosis (IPF) often experience precipitous deteriorations, termed "acute exacerbations" (AE), marked by diffuse alveolitis and altered gas exchange, resulting in a significant loss of lung function or mortality. The missense isoleucine to threonine substitution at position 73 (I73T) in the alveolar type 2 cell-restricted surfactant protein-C (SP-C) gene (SFTPC) has been linked to clinical IPF. To better understand the sequence of events that impact AE-IPF, we leveraged a murine model of inducible SP-C^I73T (SP-C^I73T/I73TFlp^+/- ) expression. Following administration of tamoxifen to 8-12-wk-old mice, an upregulation of Sftpc^I73T initiated a diffuse lung injury marked by increases in bronchoalveolar lavage fluid (BALF) protein and histochemical evidence of CD45⁺ and CD11b⁺ cell infiltrates. Flow cytometry of collagenase-digested lung cells revealed a transient, early reduction in SiglecF^hiCD11b^lowCD64^hiCD11c^hi macrophages, countered by the sequential accumulation of SiglecF^loCD11b⁺CD64^-CD11c^-CCR2⁺Ly6C⁺ immature macrophages (3 d), Ly6G⁺ neutrophils (7 d), and SiglecF^hiCD11b^hiCD11c^lo eosinophils (2 wk). By mRNA analysis, BALF cells demonstrated a time-dependent phenotypic shift from a proinflammatory (3 d) to an anti-inflammatory/profibrotic activation state, along with serial elaboration of monocyte and eosinophil recruitment factors. The i.v. administration of clodronate effectively reduced total BALF cell numbers, CCR2⁺ immature macrophages, and eosinophil influx while improving survival. In contrast, resident macrophage depletion from the intratracheal delivery of clodronate liposomes enhanced Sftpc^I73T -induced mortality. These results using Sftpc^I73T mice provide a detailed ontogeny for AE-IPF driven by alveolar epithelial dysfunction that induces a polycellular inflammation initiated by the early influx of proinflammatory CCR2⁺Ly6C^hi immature macrophages.

Curcumin inhibits the TGF-β1-dependent differentiation of lung fibroblasts via PPARγ-driven upregulation of cathepsins B and L

Pulmonary fibrosis is a progressive disease characterized by a widespread accumulation of myofibroblasts and extracellular matrix components. Growing evidences support that cysteine cathepsins, embracing cathepsin B (CatB) that affects TGF-β1-driven Smad pathway, along with their extracellular inhibitor cystatin C, participate in myofibrogenesis. Here we established that curcumin, a potent antifibrotic drug used in traditional Asian medicine, impaired the expression of both α-smooth muscle actin and mature TGF-β1 and inhibited the differentiation of human lung fibroblasts (CCD-19Lu cells). Curcumin induced a compelling upregulation of CatB and CatL. Conversely cystatin C was downregulated, which allowed the recovery of the peptidase activity of secreted cathepsins and the restoration of the proteolytic balance. Consistently, the amount of both insoluble and soluble type I collagen decreased, reaching levels similar to those observed for undifferentiated fibroblasts. The signaling pathways activated by curcumin were further examined. Curcumin triggered the expression of nuclear peroxisome proliferator-activated receptor γ (PPARγ). Contrariwise PPARγ inhibition, either by an antagonist (2-chloro-5-nitro-N-4-pyridinyl-benzamide) or by RNA silencing, restored TGF-β1-driven differentiation of curcumin-treated CCD-19Lu cells. PPARγ response element (PPRE)-like sequences were identified in the promoter regions of both CatB and CatL. Finally, we established that the transcriptional induction of CatB and CatL depends on the binding of PPARγ to PPRE sequences as a PPARγ/Retinoid X Receptor-α heterodimer.

Interstitial Pneumonia With Autoimmune Features: An Emerging Challenge at the Intersection of Rheumatology and Pulmonology

Interstitial lung disease (ILD) remains a cause of significant morbidity and mortality in patients with connective tissue disease (CTD)-associated ILD. While some patients meet clear classification criteria for a systemic rheumatic disease, a subset of patients do not meet classification criteria but still benefit from immunosuppressive therapy. In 2015, the American Thoracic Society and European Respiratory Society described classification criteria for interstitial pneumonia with autoimmune features (IPAF) to identify patients with lung-predominant CTD who lack sufficient features of a systemic rheumatic disease to meet classification criteria. Although these criteria are imperfect, they are an important attempt to classify the patient with undifferentiated disease for future study. Rheumatologists play a key role in the evaluation of potential IPAF in patients, especially as many patients with a myositis-spectrum disease (e.g., non-Jo-1 antisynthetase syndrome, anti-melanoma differentiation-associated protein 5 antibody inflammatory myositis, or anti-PM/Scl antibody-associated inflammatory myositis) would be classified under IPAF using the currently available criteria for inflammatory myositis, and would therefore benefit from rheumatologic comanagement. The aim of this review was to describe the historical context that led to the development of these criteria and to discuss the limitations of the current criteria, diagnostic challenges, treatment options, and strategies for disease monitoring.

Acute exacerbation of idiopathic pulmonary fibrosis: a 10-year single-centre retrospective study

Introduction

In 2016, an international working group proposed a revised definition and new diagnostic criteria for the acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF). Based on these criteria, AE-IPF was diagnosed regardless of the presence or absence of a known trigger and categorised as triggered (T-AE) or idiopathic (I-AE) AE-IPF. However, the clinical characteristics of the newly defined AE-IPF and clinical differences between T-AE and I-AE are unresolved.

Methods

We retrospectively analysed 64 patients with AE-IPF (I-AE (42), T-AE (22)) admitted to our hospital over a 10- year period.

Results

I-AE and T-AE cases did not show differences in in-hospital and long-term outcomes (in-hospital mortality: I-AE 52.4%, T-AE 59.1%, p=0.61; long-term mortality: p=0.68). In the I-AE group, significantly more patients received corticosteroid therapy before an AE (I-AE 35.7%, T-AE 4.5%; p=0.01). Significantly more patients in the T-AE group had lung cancer (I-AE 7.1%, T-AE 59.1%, p<0.001). I-AE occurred more frequently in winter while T-AE did not show seasonality. The white blood cell (WBC) count and haemoglobin (Hb) level were independent predictors of in-hospital deaths in I-AE (WBC: OR 1.87; 95% CI 1.09 to 4.95, p=0.01; Hb: OR 0.26, 95%  CI 0.04 to 0.78, p=0.01) but not T-AE.

Discussion

With the introduction of new criteria for AE-IPF, a retrospective study over a 10-year period showed a lack of prognostic difference between I-AE and T-AE. The WBC count and Hb level predicted in-hospital outcome in I-AE cases.

An Open-Label, Phase II Study of the Safety of Pirfenidone in Patients with Idiopathic Pulmonary Fibrosis (PIPF-002)

INTRODUCTION

PIPF-002 was a phase 2, multicenter, open-label study of pirfenidone in patients with idiopathic pulmonary fibrosis (IPF) or other types of pulmonary fibrosis (PF). PIPF-002 terminated after pirfenidone became commercially available in the United States. The goal of PIPF-002 was to characterize the long-term safety of pirfenidone in these patients.

METHODS

Between August 2003 and September 2006, 83 patients (IPF: 81, PF: 2) enrolled. Patients received pirfenidone in three divided doses daily, with the maintenance dose and schedule determined by enrollment group assignment. Treatment continued until patient withdrawal or study termination (2015). Treatment-emergent adverse events (TEAEs) were assessed by descriptive statistics.

RESULTS

At baseline, median age was 70 years, mean percent predicted forced vital capacity was 67.7%, 33.7% of patients had cardiac disorders, 51.8% had gastroesophageal reflux disease, and 63.9% were receiving concomitant prednisone. Median pirfenidone dose and exposure duration were 2400 mg/day and 3.0 years, respectively. Cumulative total exposure was 279.7 patient-exposure years (PEY). Most patients (98.8%) reported ≥ 1 TEAE, with an overall incidence rate of 460.5 per 100 PEY. The most frequent TEAEs (incidence rate per 100 PEY) were nausea (23.6), IPF progression (16.1), fatigue (11.8), dyspnea (11.4), upper respiratory tract infection (11.4), and cough (10.7). Serious TEAEs were reported in 49 patients; the most frequent serious TEAEs were IPF progression and pneumonia. The most common reason for discontinuation was TEAEs (35 patients; 12.5 patients per 100 PEY), most frequently IPF progression and nausea. Overall, 21 patients died (7.5 per 100 PEY); 16 deaths were IPF-related.

CONCLUSIONS

Long-term safety and tolerability of pirfenidone findings in this study were consistent with the known safety profile of pirfenidone; no new safety signals were identified. These data support the continued use of pirfenidone in patients with IPF.

FUNDING

F. Hoffmann-La Roche Ltd./Genentech, Inc.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT00080223. Plain language summary available for this article.

Epithelial cell-derived cytokines CST3 and GDF15 as potential therapeutics for pulmonary fibrosis

While wound healing is completed, the epithelium functions to normalize the interstitial context by eliminating fibroblasts excited during matrix reconstruction. If not, tissues undergo pathologic fibrosis. Pulmonary fibrosis is a fatal and hardly curable disorder. We here tried to identify epithelium-derived cytokines capable of ameliorating pulmonary fibrosis. Human lung fibroblasts were inactivated in epithelial cell-conditioned media. Cystatin C (CST3) and growth differentiation factor 15 (GDF15) were found to be enriched in the conditioned media and to inhibit the growth and activation of lung fibroblasts by inactivating the TGF–Smad pathway. In mouse and human lungs with interstitial fibrosis, CST3 and GDF15 expressions were markedly reduced, and the restoration of these cytokines alleviated the fibrotic changes in mouse lungs. These results suggest that CST3 and GDF15 are bona fide regulators to prevent excessive proliferation and activation of fibroblasts in injured lungs. These cytokines could be potential therapeutics for ameliorating interstitial lung fibrosis.

A model of human lung fibrogenesis for the assessment of anti-fibrotic strategies in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease with limited therapeutic options. KCa3.1 ion channels play a critical role in TGFβ1-dependent pro-fibrotic responses in human lung myofibroblasts. We aimed to develop a human lung parenchymal model of fibrogenesis and test the efficacy of the selective KCa3.1 blocker senicapoc. 2 mm3 pieces of human lung parenchyma were cultured for 7 days in DMEM ± TGFβ1 (10 ng/ml) and pro-fibrotic pathways examined by RT-PCR, immunohistochemistry and collagen secretion. Following 7 days of culture with TGFβ1, 41 IPF- and fibrosis-associated genes were significantly upregulated. Immunohistochemical staining demonstrated increased expression of ECM proteins and fibroblast-specific protein after TGFβ1-stimulation. Collagen secretion was significantly increased following TGFβ1-stimulation. These pro-fibrotic responses were attenuated by senicapoc, but not by dexamethasone. This 7 day ex vivo model of human lung fibrogenesis recapitulates pro-fibrotic events evident in IPF and is sensitive to KCa3.1 channel inhibition. By maintaining the complex cell-cell and cell-matrix interactions of human tissue, and removing cross-species heterogeneity, this model may better predict drug efficacy in clinical trials and accelerate drug development in IPF. KCa3.1 channels are a promising target for the treatment of IPF.

The Processes and Mechanisms of Cardiac and Pulmonary Fibrosis

Fibrosis is the formation of fibrous connective tissue in response to injury. It is characterized by the accumulation of extracellular matrix components, particularly collagen, at the site of injury. Fibrosis is an adaptive response that is a vital component of wound healing and tissue repair. However, its continued activation is highly detrimental and a common final pathway of numerous disease states including cardiovascular and respiratory disease. Worldwide, fibrotic diseases cause over 800,000 deaths per year, accounting for ~45% of total deaths. With an aging population, the incidence of fibrotic disease and subsequently the number of fibrosis-related deaths will rise further. Although, fibrosis is a well-recognized cause of morbidity and mortality in a range of disease states, there are currently no viable therapies to reverse the effects of chronic fibrosis. Numerous predisposing factors contribute to the development of fibrosis. Biological aging in particular, interferes with repair of damaged tissue, accelerating the transition to pathological remodeling, rather than a process of resolution and regeneration. When fibrosis progresses in an uncontrolled manner, it results in the irreversible stiffening of the affected tissue, which can lead to organ malfunction and death. Further investigation into the mechanisms of fibrosis is necessary to elucidate novel, much needed, therapeutic targets. Fibrosis of the heart and lung make up a significant proportion of fibrosis-related deaths. It has long been established that the heart and lung are functionally and geographically linked when it comes to health and disease, and thus exploring the processes and mechanisms that contribute to fibrosis of each organ, the focus of this review, may help to highlight potential avenues of therapeutic investigation.

Pulmonary delivery of liposomal dry powder inhaler formulation for effective treatment of idiopathic pulmonary fibrosis

Dry powder inhaler Liposomes were prepared to investigate the effectiveness of pulmonary delivery of Colchicine and Budesonide for Idiopathic Pulmonary fibrosis. Budesonide (BUD) and Colchicine (COL) liposomes were prepared by thin layer film hydration method (TFH) using 1,2-Dipalmitoyl-sn-glycero-3- phosphoglycerol sodium (DPPG), Hydrogenated Soyaphosphotidylcholine (HSPC), Soyaphosphatidylcholine (SPC), cholesterol (CHOL) and drug in different weight ratios. The optimum lipid composition for BUD (74.22 ± 0.97%) was DPPG: HSPC: CHOL (4:5:1) and for COL (50.94 ± 2.04%) was DPPG: SPC: CHOL (3:6:1). These compositions retained drug for a longer period of time so selected for further study. Liposomes were found to be spherical in shape with mean size below 100 nm. Liposomes lyophilized using Mannitol as carrier and cryoprotectant showed high entrapment efficiency (97.89 - 98.6%). The powder was dispersed through an Andersen cascade impactor to evaluate the performance of the aerosolized powder. It was found that prepared liposomal dry powder inhaler (DPIs) sustained the drug release up to 24 hours. Optimized Budesonide DPI Formulation B2 (86.53 ± 1.9%), Colchicine DPI Formulation C2 (90.54 ± 2.3 %) and BUD and COL DPI Combination M2 (89.91 ± 1.8%, 91.23 ± 1.9%). Histopathological results, measurements of lung hydroxyproline content, Myeloperoxidase activity indicated that liposomal dry powder inhaler administration attenuates lung fibrosis induced by bleomycin. Long term stability studies indicated that lyophilised BUD and COL liposomes were stable for 6 months at (25 °C ± 2 °C, 60% ± 5% RH) and refrigerated conditions (2 - 8 °C). These results supported that combination of budesonide and colchicine liposomal dry powder inhaler pulmonary drug delivery for treatment of idiopathic Pulmonary Fibrosis exhibits prolonged drug retention at targeted site and reduces the systemic exposure.

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.

Retrospective observational study of trends in hospital admissions for idiopathic pulmonary fibrosis in Spain (2004-2013) using administrative data

OBJECTIVE

To assess changes in incidence, diagnostic procedures, comorbidity profiles, length of hospital stay (LOHS), economic costs and in-hospital mortality (IHM) associated with idiopathic pulmonary fibrosis (IPF).

METHODS

We identified patients hospitalised with IPF in Spain from 2004 to 2013. Data were collected from the National Hospital Discharge Database.

RESULTS

The study population comprised 22 214 patients. Overall crude incidence increased from 3.82 to 6.98 admissions per 100 000 inhabitants from 2004 to 2013 (p<0.05). The percentage of lung biopsies decreased significantly from 10.68% in 2004 to 9.04% in 2013 (p<0.05). The percentage of patients with a Charlson comorbidity index ≥2 was 15.14% in 2004, increasing to 26.95% in 2013 (p<0.05). IHM decreased from 14.77% in 2004 to 13.72% in 2013 (adjusted OR 0.98; 95% CI 0.97 to 0.99). Mean LOHS was 11.87±11.18 days in 2004, decreasing to 10.20±11.12 days in 2013 (p<0.05). The mean cost per patient increased from €4838.51 in 2004 to €5410.90 in 2013 (p<0.05).

CONCLUSIONS

The frequency of hospital admissions for IPF increased during the study period, as did healthcare costs. However, IHM and LOHS decreased.

Efficacy of antioxidant in idiopathic pulmonary fibrosis: A systematic review and meta-analysis

Idiopathic pulmonary fibrosis (IPF) is a chronic oxido-inflammatory disorder of the lung. Oxidative stress is widely recognized as a central feature of IPF. Antioxidant therapy has been proposed as an effective treatment for IPF. An array of clinical trials describing the therapeutic impact of these drugs have been reporting albeit with conflicting evidence points. We performed a meta-analysis of trials in which efficacy of antioxidant therapy was compared with control in IPF. Systematic literature search was conducted in PubMed, EMBASE, the Cochrane Library, CPCI-S (Conference Proceedings Citation Index-Science), ICTRP (International Clinical Trials Registry Platform), and Google Scholar till June 2016 by two independent researchers. Various outcomes such as changes in pulmonary function tests (change in vital capacity [ΔVC], change in forced vital capacity [ΔFVC], change in percentage of predicted vital capacity [Δ%VC], and change in percentage of predicted carbon monoxide diffusing capacity [Δ%DLco]), changes in 6 minutes walking test distance (Δ6MWT), rates of adverse events, and rates of death, were included. All statistical analyses were performed using RevMan V.5.3. Twelve studies (n = 1062) were identified that used antioxidants (N-acetylcysteine and lecithinized superoxide dismutase) as a treatment for IPF. Overall, there was no association of antioxidant therapy with ΔFVC (SMD = 0.27, 95% CI:-0.07 to 0.61; P = 0.12), ΔFVC (%) (SMD = -0.10, 95% CI:-0.56 to 0.36; P = 0.66) and 6MWT (SMD = -0.04, 95% CI:-0.11 to 0.20; P = 0.59) in IPF patients. However, combined antioxidant therapy was found to be associated with %VC (SMD = 0.37, 95% CI: 0.09 to 0.64; P = 0.008) and Δ%DLco (SMD = 0.15, 95% CI: 0.00 to 0.29; P = 0.05) in IPF patients. Strong evidence was obtained that the antioxidants increased adverse effects adverse events (OR = 1.56, 95% CI: 0.75 to 3.24; P = 0.23) but it did not associate mortality (OR = 0.96, 95% CI: 0.44 to 2.11; P = 0.92). The use of significant clinical heterogeneity, low statistical power, high dropout rates, duration of follow-ups, and dosing regimens of antioxidant agents. Combined antioxidant therapy seems to be a safe and effective therapy for IPF patients which provides a more beneficial effect in terms of VC, and DLco rather than monotherapy. Further randomized controlled trials with homogeneous outcome measures are needed.

Baicalin attenuates bleomycin-induced pulmonary fibrosis via adenosine A2a receptor related TGF-β1-induced ERK1/2 signaling pathway

BACKGROUND

Baicalin has been reported to have anti-fibrosis effect; however, its mechanism still remains to be elucidated. Adenosine A2a receptor (A2aR) is a novel inflammation regulator, and transforming growth factor-β1 (TGF-β1)-induced extracellular signal regulated kinase1/2 (ERK1/2) signaling pathway plays an important role in idiopathic pulmonary fibrosis (IPF). This study was to explore the relationship of A2aR and TGF-β1-induced ERK1/2 in bleomycin (BLM)-induced pulmonary fibrosis in mice, and to investigate whether A2aR mediate the anti-fibrosis effect of Baicalin on BLM-induced pulmonary fibrosis.

METHODS

The A2aR-/- and A2aR+/+ mice were respectively divided into three groups: control group, model group, baicalin group. Pulmonary fibrosis was induced in mice of model groups by intratracheal instillation of bleomycin, and baicalin was administered in mice of baicalin groups daily for 28 days. Histopathological and ultrastructural changes of lung tissues were evaluated. Lung coefficient and the levels of hydroxyproline (HYP) in lung tissues were measured at the same time. The levels of serum TGF-β1 were measured by ELISA. The expression of TGF-β1, ERK1/2, p-ERK1/2 and A2aR were detected by western blot and immunohistochemical staining techniques.

RESULTS

Severe lung fibrosis was observed in the bleomycin-treated mice on day 28. The histopathological findings and collagen content of lung tissues were much severer/higher in A2aR-/- mice than in A2aR+/+ mice. We also showed that TGF-β1 and p-ERK1/2 were upregulated in bleomycin-treated mice and expressed higher in A2aR-/- mice compared to A2aR+/+ mice. Besides, bleomycin-treated A2aR+/+ mice had increased A2aR level in lungs. However, long-term treatment with baicalin in A2aR-/- and A2aR+/+ mice significantly ameliorated the histopathological changes in lungs. Moreover, Increased TGF-β1 and p-ERK1/2 expressions in bleomycin-treated A2aR-/- and A2aR+/+ mice were obviously diminished by baicalin. The baicalin-treated A2aR-/- mice had severer lung fibrosis and higher expressions of TGF-β1 and p-ERK1/2 than A2aR+/+ mice. Baicalin has also upregulated the expression of A2aR in A2aR+/+ mice.

CONCLUSIONS

Genetic inactivation of A2aR exacerbated the pathological processes of bleomycin-induced pulmonary fibrosis. Together, baicalin could inhibit BLM-induced pulmonary fibrosis by upregulating A2aR, suggesting A2aR as a therapeutic target of baicalin for the treatment of pulmonary fibrosis.

Update on diagnosis and treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a type of chronic fibrosing interstitial pneumonia, of unknown etiology, which is associated with a progressive decrease in pulmonary function and with high mortality rates. Interest in and knowledge of this disorder have grown substantially in recent years. In this review article, we broadly discuss distinct aspects related to the diagnosis and treatment of idiopathic pulmonary fibrosis. We list the current diagnostic criteria and describe the therapeutic approaches currently available, symptomatic treatments, the action of new drugs that are effective in slowing the decline in pulmonary function, and indications for lung transplantation.

Attenuation of lung fibrosis in mice with a clinically relevant inhibitor of glutathione-S-transferase π

Idiopathic pulmonary fibrosis (IPF) is a debilitating lung disease characterized by excessive collagen production and fibrogenesis. Apoptosis in lung epithelial cells is critical in IPF pathogenesis, as heightened loss of these cells promotes fibroblast activation and remodeling. Changes in glutathione redox status have been reported in IPF patients. S-glutathionylation, the conjugation of glutathione to reactive cysteines, is catalyzed in part by glutathione-S-transferase π (GSTP). To date, no published information exists linking GSTP and IPF to our knowledge. We hypothesized that GSTP mediates lung fibrogenesis in part through FAS S-glutathionylation, a critical event in epithelial cell apoptosis. Our results demonstrate that GSTP immunoreactivity is increased in the lungs of IPF patients, notably within type II epithelial cells. The FAS-GSTP interaction was also increased in IPF lungs. Bleomycin- and AdTGFβ-induced increases in collagen content, α-SMA, FAS S-glutathionylation, and total protein S-glutathionylation were strongly attenuated in Gstp-/- mice. Oropharyngeal administration of the GSTP inhibitor, TLK117, at a time when fibrosis was already apparent, attenuated bleomycin- and AdTGFβ-induced remodeling, α-SMA, caspase activation, FAS S-glutathionylation, and total protein S-glutathionylation. GSTP is an important driver of protein S-glutathionylation and lung fibrosis, and GSTP inhibition via the airways may be a novel therapeutic strategy for the treatment of IPF.

Efficacy of N-Acetylcysteine in Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

There are a number of conflicting reports describing the clinical outcomes of using N-acetylcysteine for the treatment of idiopathic pulmonary fibrosis. We have, therefore, performed a meta-analysis to evaluate the efficacy of N-acetylcysteine, compared with control, for the treatment of idiopathic pulmonary fibrosis.Original controlled clinical trials evaluating the efficacy of N-acetylcysteine for the treatment of idiopathic pulmonary fibrosis were included in the analysis. Searches for relevant articles were carried out in July 2014 by 2 independent researchers using PubMed, Embase, Cochrane Central, and Google Scholar. Change in forced vital capacity, change in percentage of predicted vital capacity, change in percentage of predicted carbon monoxide diffusing capacity, changes in 6 minutes walking test distance, rate of adverse events, and rate of death were expressed as outcomes using RevMan 5.0.1.Five trials, with a total of 564 patients, were included in this meta-analysis. The meta-analysis showed that the control group had significant decreases in percentage of predicted vital capacity (standardized mean difference [SMD] = 0.37; 95% confidence interval [CI]: 0.13 to -0.62; P = 0.003) and 6 minutes walking test distance (SMD = 0.25; 95% CI: 0.02-0.48; P = 0.04). There were no statistically significant differences in forced vital capacity (SMD = 0.07; 95% CI: -0.13-0.27; P = 0.52), percentage of predicted carbon monoxide diffusing capacity (SMD = 0.12; 95% CI: -0.06-0.30; P = 0.18), rates of adverse events (odd ratio = 4.50; 95% CI: 0.19-106.41; P = 0.35), or death rates (odd ratio = 1.79; 95% CI: 0.3-5.12; P = 0.28) between the N-acetylcysteine group and the control group.N-Acetylcysteine was found to have a significant effect only on decreases in percentage of predicted vital capacity and 6 minutes walking test distance. N-acetylcysteine showed no beneficial effect on changes in forced vital capacity, changes in predicted carbon monoxide diffusing capacity, rates of adverse events, or death rates.

New perspectives on management of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive parenchymal lung disease characterized by a median survival of 3-5 years following diagnosis. The diagnosis is based on clinical, radiological and histopathological evaluation. Therefore, a multidisciplinary team is needed to reach the correct diagnosis. For a long time, supportive care and lung transplantation in selected cases, have been considered the only possible treatments for IPF. In the last decade many studies have investigated IPF pathogenesis, leading to an improved knowledge of the mechanisms underlying the disease and to the approval of two new drugs for IPF treatment (pirfenidone and nintedanib). The therapeutic approach of IPF cannot be limited to the administration of antifibrotic drugs, but it is necessary for improving the quality of life of patients and for facilitating, as far as possible, the performance of normal daily activities and relationships. IPF patients are also afflicted by disease-related complications such as gastroesophageal reflux, pulmonary hypertension, acute exacerbations and an increased risk of developing lung cancer. The clinician who treats IPF patients, should also treat these possible complications to slow disease progression, thus maintaining the possibility of a pulmonary transplantation.

Inflammatory response mechanisms exacerbating hypoxemia in coexistent pulmonary fibrosis and sleep apnea

Mediators of inflammation, oxidative stress, and chemoattractants drive the hypoxemic mechanisms that accompany pulmonary fibrosis. Patients with idiopathic pulmonary fibrosis commonly have obstructive sleep apnea, which potentiates the hypoxic stimuli for oxidative stress, culminating in systemic inflammation and generalized vascular endothelial damage. Comorbidities like pulmonary hypertension, obesity, gastroesophageal reflux disease, and hypoxic pulmonary vasoconstriction contribute to chronic hypoxemia leading to the release of proinflammatory cytokines that may propagate clinical deterioration and alter the pulmonary fibrotic pathway. Tissue inhibitor of metalloproteinase (TIMP-1), interleukin- (IL-) 1α, cytokine-induced neutrophil chemoattractant (CINC-1, CINC-2α/β), lipopolysaccharide induced CXC chemokine (LIX), monokine induced by gamma interferon (MIG-1), macrophage inflammatory protein- (MIP-) 1α, MIP-3α, and nuclear factor- (NF-) κB appear to mediate disease progression. Adipocytes may induce hypoxia inducible factor (HIF) 1α production; GERD is associated with increased levels of lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and tumor necrosis factor alpha (TNF-α); pulmonary artery myocytes often exhibit increased cytosolic free Ca2+. Protein kinase C (PKC) mediated upregulation of TNF-α and IL-1β also occurs in the pulmonary arteries. Increased understanding of the inflammatory mechanisms driving hypoxemia in pulmonary fibrosis and obstructive sleep apnea may potentiate the identification of appropriate therapeutic targets for developing effective therapies.

Pharmacologic therapies for idiopathic pulmonary fibrosis, past and future

Idiopathic pulmonary fibrosis (IPF) is a severe, progressive fibrotic disease of the lung of unknown etiology that affects approximately 150,000 patients in the United States. It carries a median survival of two to three years, but clinical course can vary markedly from patient to patient. There has been no established treatment for IPF, but recent advances in coordinated clinical trials through groups such as IPFnet and academia-industry partnerships have allowed this relatively rare disease to be studied in much greater depth. Historically, the default therapy for IPF was a combination of prednisone, N-acetylcysteine, and azathioprine, but recent trials have shown that this regimen actually increases mortality. An enormous body of work in recent years, spanning the bench to the bedside, has radically altered our understanding of the molecular mechanisms underlying IPF. Newer modalities, particularly those involving monoclonal antibodies targeted at specific pathways known to contribute to the fibrotic process, have generated a great deal of excitement in the field, and recent clinical trials on therapies such as pirfenidone and nintedanib herald a new era in targeted IPF therapies.