Idiopathic pulmonary fibrosis: current treatment options and critical appraisal of nintedanib

Analysis of the safety and efficacy of different plasma concentrations of pirfenidone in patients with idiopathic pulmonary fibrosis

The high incidence and mortality of idiopathic pulmonary fibrosis (IPF) have led to the widespread use of antifibrotic drugs such as pirfenidone; however, the associated adverse reactions greatly vary among individuals and the dose is not fixed. To date, no reliable blood concentration range of pirfenidone is available to monitor adverse reactions and clinical efficacy. This real study assessed the efficacy and safety of different plasma concentrations of pirfenidone in patients with IPF. The study included 99 patients with IPF orally treated with pirfenidone capsules for at least 52 weeks. Ultra-performance liquid chromatography–mass spectrometry was used to analyze drug plasma concentrations. The annual rate of forced vital capacity (FVC) decline, assessed at week 52, was set as the primary end point. Secondary end points were the change from the baseline in the 6-min walk distance (6 MWD) and the time to the first acute exacerbation of IPF, both of which evaluated over 52 weeks. In the total population, the annual FVC decline in the high-concentration group was −90.0 ml per year versus −260.0 ml per year in the low-concentration group, for a between-group difference of 190.3 ml per year. The proportion of patients treated with high plasma concentrations of pirfenidone who showed an absolute decline of ≥10% in FVC% predicted, with a 6 MWD reduction of ≥50 m, or died, was lower than that of patients treated with low plasma concentrations of pirfenidone. High concentrations of pirfenidone reduced the risk of acute exacerbation in patients with IPF. Considerable differences were not observed for the total St. George’s Respiratory Questionnaire score or the rates of death between the high- and low-concentration groups. Mild to moderate adverse events, mainly involving the gastrointestinal system and the skin, were more common in the high-concentration group than in the low-concentration group but did not lead to termination of treatment in most cases. Our results suggest that treatment of IPF with high blood concentration of pirfenidone is both safe and effective. In the case of tolerable adverse reactions, patients with IPF may benefit from high concentrations of pirfenidone.

Targeting the lung epithelium after intravenous delivery by directed evolution of underexplored sites on the AAV capsid

Advances in adeno-associated virus (AAV) engineering have provided exciting new tools for research and potential solutions for gene therapy. However, the lung has not received the same tailored engineering as other major targets of debilitating genetic disorders. To address this, here we engineered the surface-exposed residues AA452-458 of AAV9 capsid proteins at the three-fold axis of symmetry and employed a Cre-transgenic-based screening platform to identify AAV capsids targeted to the lung after intravenous delivery in mice. Using a custom image processing pipeline to quantify transgene expression across whole tissue images, we found that one engineered variant, AAV9.452sub.LUNG1, displays dramatically improved transgene expression in lung tissue after systemic delivery in mice. This improved transduction extends to alveolar epithelial type II cells, expanding the toolbox for gene therapy research for diseases specific to the lung.

The Inflammasome NLR Family Pyrin Domain-Containing Protein 3 (NLRP3) as a Novel Therapeutic Target for Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a dramatic disease without cure. The US Food and Drug Administration-approved drugs, pirfenidone and nintedanib, only slow disease progression. The clinical investigation of novel therapeutic approaches for IPF is an unmet clinical need. Nucleotide-binding oligomerization domain-like receptor or NOD-like receptors are pattern recognition receptors capable of binding a large variety of stress factors. NLR family pyrin domain-containing protein 3 (NLRP3), once activated, promotes IL-1β, IL-18 production, and innate immune responses. Multiple reports indicate that the inflammasome NLRP3 is overactivated in IPF patients, leading to increased production of class I IL and collagens. Similarly, data from animal models of pulmonary fibrosis confirm the role of NLRP3 in the development of chronic lung injury and pulmonary fibrosis. This report provides a review of the evidence of NLRP3 activation in IPF and of NLRP3 inhibition in different animal models of fibrosis, and highlights the recent advances in direct and indirect NLRP3 inhibitors.

The Anti-Fibrotic Effect of Cold Atmospheric Plasma on Localized Scleroderma In Vitro and In Vivo

Cold Atmospheric Plasma (CAP) has shown promising results in the treatment of various skin diseases. The therapeutic effect of CAP on localized scleroderma (LS), however, has not yet been evaluated. We investigated the effects of CAP on LS by comparing human normal fibroblasts (hNF), human TGF-β-activated fibroblasts (hAF), and human localized scleroderma-derived fibroblasts (hLSF) after direct CAP treatment, co-cultured with plasma-treated human epidermal keratinocytes (hEK) and with an experimental murine model of scleroderma. In hAF and hLSF, 2 min CAP treatment with the MicroPlaSterβ^® plasma torch did not affect pro-fibrotic gene expression of alpha smooth muscle actin, fibroblast activating protein, and collagen type I, however, it promoted re-expression of matrix metalloproteinase 1. Functionally, CAP treatment reduced cell migration and stress fiber formation in hAF and hLSF. The relevance of CAP treatment was confirmed in an in vivo model of bleomycin-induced dermal fibrosis. In this model, CAP-treated mice showed significantly reduced dermal thickness and collagen deposition as well as a decrease in both alpha smooth muscle actin-positive myofibroblasts and CD68-positive macrophages in the affected skin in comparison to untreated fibrotic tissue. In conclusion, this study provides the first evidence for the successful use of CAP for treating LS and may be the basis for clinical trials including patients with LS.

DSP rs2076295 variants influence nintedanib and pirfenidone outcomes in idiopathic pulmonary fibrosis: a pilot study

BACKGROUND

The antifibrotic drugs nintedanib and pirfenidone are used for the treatment of idiopathic pulmonary fibrosis (IPF). We analysed the association of common profibrotic polymorphisms in MUC5B (mucin 5B, rs35705950) and DSP (desmoplakin, rs2076295) on antifibrotic treatment outcomes in IPF.

METHODS

MUC5B rs35705950 and DSP rs2076295 were assessed in IPF patients (n = 210, 139 men/71 women) from the Czech EMPIRE registry and age- or sex-matched healthy individuals (n = 205, 125 men/80 women). Genetic data were collated with overall survival (OS), acute exacerbation episodes, worsening lung function and antifibrotic treatment.

RESULTS

We confirmed overexpression of the MUC5B rs35705950*T allele (55.2% versus 20.9%, p < 0.001) and the DSP rs2076295*G allele (80.4% versus 68.3%, p < 0.001) in IPF compared with controls. On antifibrotic drugs, lower mortability was observed in IPF patients with DSP G* allele (p = 0.016) and MUC5B T* allele (p = 0.079). Carriers of the DSP rs2076295*G allele benefitted from nintedanib treatment compared with TT genotype by a longer OS [hazard ratio (HR) = 7.99; 95% confidence interval (CI) = 1.56-40.90; p = 0.013] and a slower decline in lung function (HR = 8.51; 95% CI = 1.68-43.14; p = 0.010). Patients with a TT genotype (rs2076295) benefitted from treatment with pirfenidone by prolonged OS (p = 0.040; HR = 0.35; 95% CI = 0.13-0.95) compared with nintedanib treatment. Both associations were confirmed by cross-validation analysis. After stratifying by MUC5B rs35705950*T allele carriage, no difference in treatment outcome was observed for nintedanib or pirfenidone (p = 0.784). In the multivariate model, smoking, age, forced vital capacity (FVC) and DL_CO (diffuse lung capacity) at the IPF diagnosis were associated with survival.

CONCLUSION

Our real-world study showed that IPF patients with MUC5B T* allele or DSP G* allele profit from antifibrotic treatment by lower mortability. Moreover, carriers of the DSP rs2076295*G allele benefit from treatment with nintedanib, and TT genotype from treatment with pirfenidone. MUC5B rs35705950 did not impact the outcome of treatment with either nintedanib or pirfenidone. Our single-registry pilot study should be confirmed with an independent patient cohort.

Lung function and cardiovascular disease: a two-sample Mendelian randomisation study

BACKGROUND

Observational studies suggest an association between reduced lung function and risk of coronary artery disease and ischaemic stroke, independent of shared cardiovascular risk factors such as cigarette smoking. We use the latest genetic epidemiological methods to determine whether impaired lung function is causally associated with an increased risk of cardiovascular disease.

METHODS AND FINDINGS

Mendelian randomisation uses genetic variants as instrumental variables to investigate causation. Preliminary analysis used two-sample Mendelian randomisation with lung function single nucleotide polymorphisms. To avoid collider bias, the main analysis used single nucleotide polymorphisms for lung function identified from UKBiobank in a multivariable Mendelian randomisation model conditioning for height, body mass index and smoking.Multivariable Mendelian randomisation shows strong evidence that reduced forced vital capacity (FVC) causes increased risk of coronary artery disease (OR 1.32, 95% CI 1.19-1.46 per standard deviation). Reduced forced expiratory volume in 1 s (FEV₁) is unlikely to cause increased risk of coronary artery disease, as evidence of its effect becomes weak after conditioning for height (OR 1.08, 95% CI 0.89-1.30). There is weak evidence that reduced lung function increases risk of ischaemic stroke.

CONCLUSION

There is strong evidence that reduced FVC is independently and causally associated with coronary artery disease. Although the mechanism remains unclear, FVC could be taken into consideration when assessing cardiovascular risk and considered a potential target for reducing cardiovascular events. FEV₁ and airflow obstruction do not appear to cause increased cardiovascular events; confounding and collider bias may explain previous findings of a causal association.

Age-Related Dynamics of Lung-Resident Memory CD8+ T Cells in the Age of COVID-19

Following respiratory viral infections or local immunizations, lung resident-memory T cells (T_RM) of the CD8 lineage provide protection against the same pathogen or related pathogens with cross-reactive T cell epitopes. Yet, it is now clear that, if homeostatic controls are lost following viral pneumonia, CD8 T_RM cells can mediate pulmonary pathology. We recently showed that the aging process can result in loss of homeostatic controls on CD8 T_RM cells in the respiratory tract. This may be germane to treatment modalities in both influenza and coronavirus disease 2019 (COVID-19) patients, particularly, the portion that present with symptoms linked to long-lasting lung dysfunction. Here, we review the developmental cues and functionalities of CD8 T_RM cells in viral pneumonia models with a particular focus on their capacity to mediate heterogeneous responses of immunity and pathology depending on immune status.

Spred2-deficiency enhances the proliferation of lung epithelial cells and alleviates pulmonary fibrosis induced by bleomycin

The mitogen-activated protein kinase (MAPK) pathways are involved in many cellular processes, including the development of fibrosis. Here, we examined the role of Sprouty-related EVH-1-domain-containing protein (Spred) 2, a negative regulator of the MAPK-ERK pathway, in the development of bleomycin (BLM)-induced pulmonary fibrosis (PF). Compared to WT mice, Spred2^−/− mice developed milder PF with increased proliferation of bronchial epithelial cells. Spred2^−/− lung epithelial cells or MLE-12 cells treated with spred2 siRNA proliferated faster than control cells in vitro. Spred2^−/− and WT macrophages produced similar levels of TNFα and MCP-1 in response to BLM or lipopolysaccharide and myeloid cell-specific deletion of Spred2 in mice had no effect. Spred2^−/− fibroblasts proliferated faster and produced similar levels of MCP-1 compared to WT fibroblasts. Spred2 mRNA was almost exclusively detected in bronchial epithelial cells of naïve WT mice and it accumulated in approximately 50% of cells with a characteristic of Clara cells, 14 days after BLM treatment. These results suggest that Spred2 is involved in the regulation of tissue repair after BLM-induced lung injury and increased proliferation of lung bronchial cells in Spred2^−/− mice may contribute to faster tissue repair. Thus, Spred2 may present a new therapeutic target for the treatment of PF.

RELMα is Induced in Airway Epithelial Cells by Oncostatin M Without Requirement of STAT6 or IL-6 in Mouse Lungs In Vivo

Resistin-like molecule alpha (RELMα) and YM-1 are secreted proteins implicated in murine models of alternatively activated macrophage (AA/M2) accumulation and Th2-skewed inflammation. Since the gp130 cytokine Oncostatin M (OSM) induces a Th2-like cytokine and AA/M2 skewed inflammation in mouse lung, we here investigated regulation of RELMα and YM-1. Transient pulmonary overexpression of OSM by Adenovirus vector (AdOSM) markedly induced RELMα and YM-1 protein expression in total lung. In situ hybridization showed that RELMα mRNA was highly induced in airway epithelial cells (AEC) and was co-expressed with CD68 mRNA in some but not all CD68+ cells in parenchyma. IL-6 overexpression (a comparator gp130 cytokine) induced RELMα, but at significantly lower levels. IL-6 (assessing IL-6^-/- mice) was not required, nor was STAT6 (IL-4/13 canonical signalling) for AdOSM-induction of RELMα in AEC. AEC responded directly to OSM in vitro as assessed by pSTAT3 activation. RELMα-deficient mice showed similar inflammatory cell infiltration and cytokine responses to wt in response to AdOSM, but showed less accumulation of CD206+ AA/M2 macrophages, reduced induction of extracellular matrix gene mRNAs for COL1A1, COL3A1, MMP13, and TIMP1, and reduced parenchymal alpha smooth muscle actin. Thus, RELMα is regulated by OSM in AEC and contributes to extracellular matrix remodelling in mouse lung.

Inhibition of tyrosine kinase receptor signaling attenuates fibrogenesis in an ex vivo model of human renal fibrosis

Poor translation from animal studies to human clinical trials is one of the main hurdles in the development of new drugs. Here, we used precision-cut kidney slices (PCKS) as a translational model to study renal fibrosis and to investigate whether inhibition of tyrosine kinase receptors, with the selective inhibitor nintedanib, can halt fibrosis in murine and human PCKS. We used renal tissue of murine and human origins to obtain PCKS. Control slices and slices treated with nintedanib were studied to assess viability, activation of tyrosine kinase receptors, cell proliferation, collagen type I accumulation, and gene and protein regulation. During culture, PCKS spontaneously develop a fibrotic response that resembles in vivo fibrogenesis. Nintedanib blocked culture-induced phosphorylation of platelet-derived growth factor receptor and vascular endothelial growth factor receptor. Furthermore, nintedanib inhibited cell proliferation and reduced collagen type I accumulation and expression of fibrosis-related genes in healthy murine and human PCKS. Modulation of extracellular matrix homeostasis was achieved already at 0.1 μM, whereas high concentrations (1 and 5 μM) elicited possible nonselective effects. In PCKS from human diseased renal tissue, nintedanib showed limited capacity to reverse established fibrosis. In conclusion, nintedanib attenuated the onset of fibrosis in both murine and human PCKS by inhibiting the phosphorylation of tyrosine kinase receptors; however, the reversal of established fibrosis was not achieved.

Idiopathic and immune-related pulmonary fibrosis: diagnostic and therapeutic challenges

Interstitial lung disease (ILD) encompasses a large group of pulmonary conditions sharing common clinical, radiological and histopathological features as a consequence of fibrosis of the lung interstitium. The majority of ILDs are idiopathic in nature with possible genetic predisposition, but is also well recognised as a complication of connective tissue disease or with certain environmental, occupational or drug exposures. In recent years, a concerted international effort has been made to standardise the diagnostic criteria in ILD subtypes, formalise multidisciplinary pathways and standardise treatment recommendations. In this review, we discuss some of the current challenges around ILD diagnostics, the role of serological testing, especially, in light of the new classification of Interstitial Pneumonia with Autoimmune Features (IPAF) and discuss the evidence for therapies targeted at idiopathic and immune-related pulmonary fibrosis.

Cyclic Stretching of Fibrotic Microtissue Array for Evaluation of Anti-Fibrosis Drugs

Introduction

Progression of pulmonary fibrosis, characterized by the deterioration of lung tissue's mechanical properties, is affected by respiratory motion-induced dynamic loading. Since the development of anti-fibrosis drugs faces major hurdles in animal tests and human clinical trials, preclinical models that can recapitulate fibrosis progression under physiologically-relevant cyclic loading hold great promise. However, the integration of these two functions has not been achieved in existing models.

Methods

Recently we developed static human lung microtissue arrays that recapitulate the progressive changes in tissue mechanics during lung fibrogenesis. In the current study, we integrate the lung microtissue array with a membrane stretching system to enable dynamic loading to the microtissues. The effects of a pro-fibrotic agent and anti-fibrosis drugs were tested under cyclic stretching.

Results

Cyclic stretching that mimics respiratory motion was shown to affect the cytoskeletal organization and cellular orientation in the microtissue and cause the increase in microtissue contractility and stiffness. Fibrosis induction using TGF-β1 further promoted fibrosis-related mechanical activity of the lung microtissues. Using this system, we examined the therapeutic effects of two FDA approved anti-fibrotic drugs. Our results showed that Nintedanib was able to fully inhibit TGF-β1 induced force increase but only partially inhibited stretching induced force increase. In contrast, Pirfenidone was able to fully inhibit both TGF-β1 induced force increase and stretching-induced force increase.

Conclusions

Together, these results highlight the pathophysiologically-relevant modeling capability of the current fibrotic microtissue system and demonstrated the potential of this system to be used for anti-fibrosis drug screening.

Role of fibroblast growth factor 23 and klotho cross talk in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia that mainly affects the elderly. Several reports have demonstrated that aging is involved in the underlying pathogenic mechanisms of IPF. α-Klotho (KL) has been well characterized as an "age-suppressing" hormone and can provide protection against cellular senescence and oxidative stress. In this study, KL levels were assessed in human plasma and primary lung fibroblasts from patients with idiopathic pulmonary fibrosis (IPF-FB) and in lung tissue from mice exposed to bleomycin, which showed significant downregulation when compared with controls. Conversely, transgenic mice overexpressing KL were protected against bleomycin-induced lung fibrosis. Treatment of human lung fibroblasts with recombinant KL alone was not sufficient to inhibit transforming growth factor-β (TGF-β)-induced collagen deposition and inflammatory marker expression. Interestingly, fibroblast growth factor 23 (FGF23), a proinflammatory circulating protein for which KL is a coreceptor, was upregulated in IPF and bleomycin lungs. To our surprise, FGF23 and KL coadministration led to a significant reduction in fibrosis and inflammation in IPF-FB; FGF23 administration alone or in combination with KL stimulated KL upregulation. We conclude that in IPF downregulation of KL may contribute to fibrosis and inflammation and FGF23 may act as a compensatory antifibrotic and anti-inflammatory mediator via inhibition of TGF-β signaling. Upon restoration of KL levels, the combination of FGF23 and KL leads to resolution of inflammation and fibrosis. Altogether, these data provide novel insight into the FGF23/KL axis and its antifibrotic/anti-inflammatory properties, which opens new avenues for potential therapies in aging-related diseases like IPF.

Evaluation of Glutathione S-Transferase Inhibition Effects on Idiopathic Pulmonary Fibrosis Therapy with a Near-Infrared Fluorescent Probe in Cell and Mice Models

Idiopathic pulmonary fibrosis (IPF) is a lung-limited and progressive fibrotic disease. The early diagnosis and therapies of IPF are still full of clinical challenges. Glutathione S-transferase (GSTs) plays significant roles in promoting the formation of pulmonary fibrosis. Herein, we report a fluorescent probe (Cy-GST) for the detection of GSTs concentration fluctuations in cells and in mice models. The probe can selectively and sensitively respond to GSTs with an "off-on" type fluorescence switch. Our results demonstrated that the level of intracellular GSTs increase in the pulmonary fibrosis cells and mice models. And the IPF patients hold high levels of GSTs concentrations. Thus, GSTs are likely to play important roles in pulmonary fibrosis. The inhibitor of GSTs TLK117 can reduce the severity of pulmonary fibrosis. The synergistic treatment of TLK117 and pirfenidone have better therapeutic effects than only using pirfenidone in pulmonary fibrosis mice models. The level of GSTs in IPF may be a new potential marker for IPF diagnosis. And the inhibition of GSTs may be a new therapeutic strategy for IPF treatment.

Hydrogel-based delivery of Il-10 improves treatment of bleomycin-induced lung fibrosis in mice

Idiopathic pulmonary fibrosis (IPF) is a life-threatening progressive lung disorder with limited therapeutic options. While interleukin-10 (IL-10) is a potent anti-inflammatory and anti-fibrotic cytokine, its utility in treating lung fibrosis has been limited by its short half-life. We describe an innovative hydrogel-based approach to deliver recombinant IL-10 to the lung for the prevention and reversal of pulmonary fibrosis in a mouse model of bleomycin-induced lung injury. Our studies show that a hyaluronan and heparin-based hydrogel system locally delivers IL-10 by capitalizing on the ability of heparin to reversibly bind IL-10 without bleeding or other complications. This formulation is significantly more effective than soluble IL-10 for both preventing and reducing collagen deposition in the lung parenchyma after 7 days of intratracheal administration. The anti-fibrotic effect of IL-10 in this system is dependent on suppression of TGF-β driven collagen production by lung fibroblasts and myofibroblasts. We conclude that hydrogel-based delivery of IL-10 to the lung is a promising therapy for fibrotic lung disorders.

Human microvasculature-on-a chip: anti-neovasculogenic effect of nintedanib in vitro

Idiopathic pulmonary fibrosis is characterized by a progressive scarring and stiffening of the peripheral lung tissue that decreases lung function. Over the course of the disease, the lung microvasculature undergoes extensive remodeling. There is increased angiogenesis around fibrotic foci and an absence of microvessels within the foci. To elucidate how the anti-fibrotic drug nintedanib acts on vascular remodeling, we used an in vitro model of perfusable microvessels made with primary endothelial cells and primary lung fibroblasts in a microfluidic chip. The microvasculature model allowed us to study the impact of nintedanib on permeability, vascularized area, and cell-cell interactions. The anti-vasculogenic impact of nintedanib was visible at the minimal concentrations of 10 nM, showing a significant increase in vessel permeability. Furthermore, nintedanib decreased microvessel density, diameter, and influenced fibroblast organization around endothelial microvessels. These results show that nintedanib acts on the endothelial network formation and endothelial-perivascular interactions. Advanced in vitro microvasculature models may thus serve to pinpoint the mechanistic effect of anti-fibrotic drugs on the microvascular remodeling in 3D and refine findings from animal studies.

Stability or improvement in forced vital capacity with nintedanib in patients with idiopathic pulmonary fibrosis

In the Phase III INPULSIS® trials, nintedanib reduced the annual rate of decline in forced vital capacity (FVC) versus placebo in patients with idiopathic pulmonary fibrosis (IPF).We conducted post hoc analyses of the distribution of changes in FVC in the INPULSIS® trials and FVC changes in the open-label extension trial INPULSIS®-ON in subgroups of patients based on whether patients had shown an improvement or no decline in FVC in INPULSIS®. Analyses were descriptive.Based on the annual rate of change in FVC, 158 of 638 patients (24.8%) treated with nintedanib and 38 of 423 patients (9.0%) treated with placebo had an improvement/no decline in FVC in the INPULSIS® trials. In patients whose FVC improved/did not decline, median (interquartile range) improvements in FVC at week 52 were 76.5 (31-152) mL and 57.5 (31-103) mL in the nintedanib and placebo groups, respectively. Changes in FVC from baseline to week 48 of INPULSIS®-ON were similar in patients whose FVC improved or declined in the preceding INPULSIS® trial.In the INPULSIS® trials, treatment with nintedanib resulted in a greater proportion of patients with IPF showing an improvement/no decline in FVC compared to taking placebo. Mechanisms underlying improvement in FVC in patients with IPF are unknown.

Small Molecule Tyrosine Kinase Inhibitor Nintedanib Reduces Development of Cardiac Allograft Vasculopathy in Murine Aortic Allografts

BACKGROUND

Nintedanib is a small molecule tyrosine kinase inhibitor that blocks the action of the platelet-derived growth factor receptor (PDGFR), the vascular endothelial growth factor receptor (VEGFR) and the fibroblast growth factor receptor. All of these receptors have been shown to be involved in the development of cardiac allograft vasculopathy (CAV) after heart transplantation. We therefore hypothesized that blocking these tyrosine kinase receptors with nintedanib could prevent CAV.

METHODS

CBA/JRj (H2k) mice underwent an abdominal aortic transplantation with a graft derived from fully allogeneic C57BL/6JRj (H2b) mice. Nintedanib was given daily from the first day after transplantation until harvest on day 14 for polymerase chain reaction analysis of intragraft cytokine expression or harvest on day 30 for histological analysis of the graft.

RESULTS

Nintedanib treatment resulted in significantly reduced neointima formation in the aortic graft compared with untreated control allografts. Interestingly, the immigration of smooth muscle cells into the neointima was markedly reduced while graft infiltrating macrophages and T cells were not altered in nintedanib-treated animals. The expression of the growth factor PDGF was significantly reduced in the nintedanib group going along with a distinctly reduced expression of the corresponding receptors PDGFR α and -β.

CONCLUSIONS

Treatment with nintedanib caused a significant reduction of CAV development after aortic transplantation in mice. We hypothesize the attenuated neointima formation in nintedanib-treated animals to be mediated by a direct inhibition of intimal smooth muscle cell proliferation via reduced expression of PDGF and the appropriate receptors PDGFR α + β.

Blockade of extracellular heat shock protein 90α by 1G6-D7 attenuates pulmonary fibrosis through inhibiting ERK signaling

Pulmonary fibrosis is characterized by lung fibroblast activation and ECM deposition and has a poor prognosis. Heat shock protein 90 (Hsp90) participates in organ fibrosis, and extracellular Hsp90α (eHsp90α) promotes fibroblast activation and migration. This study aimed to investigate whether a selective anti-Hsp90α monoclonal antibody, 1G6-D7, could attenuate lung fibrosis and whether 1G6-D7 presents a protective effect by inactivating the profibrotic pathway. Our results showed that eHsp90α was increased in mice with BLM-induced pulmonary fibrosis and that 1G6-D7 attenuated inflammation and collagen deposition in the lung. TGF-β1 induced eHsp90α secretion, concomitantly promoting HFL-1 activation and ECM synthesis. 1G6-D7-mediated inhibition of eHsp90α significantly blocked these effects, meanwhile inhibiting downstream profibrotic pathways such as ERK, Akt, and P38. Human recombinant (hr)Hsp90α mimicked the effects of TGF-β1, by activating profibrotic pathways and by upregulating LRP-1. Moreover, ERK inhibition effectively blocked the effect of (hr)Hsp90α. In conclusion, 1G6-D7 significantly protects against BLM-induced pulmonary fibrosis by ameliorating fibroblast activation and ECM production, which may be through blocking ERK signaling. Our results suggest a safer molecular therapy, 1G6-D7, in pulmonary fibrosis.

Clinical use of nintedanib in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a rare lung disease characterised by progressive loss of lung function, dyspnoea and cough. IPF has a variable clinical course but a poor prognosis. Nintedanib, a tyrosine kinase inhibitor, is one of two drugs approved for the treatment of IPF. In clinical trials, nintedanib slowed disease progression by reducing the rate of decline in forced vital capacity (FVC) in patients with IPF and mild or moderate lung function impairment. The effect of nintedanib was consistent across patient subgroups defined by baseline characteristics including FVC % predicted, diffusion capacity of the lung for carbon monoxide % predicted and the presence of emphysema. Recently, it has been shown that the rate of decline in FVC and the treatment effect of nintedanib are the same in patients with preserved lung volume (FVC >90% predicted) as in patients with greater impairment in FVC, supporting the value of early treatment of IPF. The adverse events most commonly associated with nintedanib, both in clinical trials and real-world clinical practice, are mild gastrointestinal events, particularly diarrhoea. Side effects are manageable in a majority of patients through symptomatic treatment, dose reductions and treatment interruptions, enabling most patients to stay on treatment in the long term.

Perioperative management of hepatectomy in patients with interstitial pneumonia: a report of three cases and a literature review

PURPOSE

Interstitial pneumonia (IP) is a progressive and irreversible fibrosis and can be fatal if acute exacerbation (AE) occurs. While a useful risk-scoring system has been established for lung surgery, no risk evaluation exists for AE of IP related to non-pulmonary surgery. The objective of this review is to describe the management for patients with IP.

METHODS

We experienced three hepatectomy cases with IP. The first was a 72-year-old male patient diagnosed with hepatocellular carcinoma. Preoperative computed tomography (CT) revealed IP with reticular shadow at the base of both lungs. After hepatectomy, his IP became acutely exacerbated and did not improve with steroid or sivelestat treatment. The second was a 74-year-old male patient diagnosed with hepatocellular carcinoma, and the third was a 75-year-old male patient with liver metastasis. In both these cases, CT revealed a reticular shadow in the lung fields, with increased serum KL-6 levels. We administered pirfenidone for perioperative management, during which time no respiratory complications occurred.

RESULTS

Perioperative management with pirfenidone for hepatectomy accompanied by IP was successful in our cases.

CONCLUSION

We reviewed reports on the perioperative prevention, intraoperative risk factors, and treatment of postoperative AE of IP and summarized the perioperative management techniques for IP patients undergoing non-pulmonary surgery.

Targeting sphingosine-1-phosphate signaling in lung diseases

Sphingosine-1-phosphate (S1P), a simple, bioactive sphingolipid metabolite, plays a key role, both intracellularly and extracellularly, in various cellular processes such as proliferation, survival, migration, inflammation, angiogenesis, and endothelial barrier integrity. The cellular S1P level is low and is tightly regulated by its synthesis and degradation. Sphingosine Kinases (SphKs) 1 and 2, catalyze the ATP-dependent phosphorylation of sphingosine to S1P, while the degradation is mediated by the reversible dephosphorylation catalyzed by the S1P phosphatases and lipid phosphate phosphatases and the irreversible degradation to hexadecenal and ethanolamine phosphate by sphingosine-1-phosphate lyase (S1PL). As a ligand for specific G-protein-coupled receptors, S1P1-5, which are differentially expressed in different cell types, S1P generates downstream signals that play crucial role in developmental and disease related pathologies. In addition to acting extracellularly on receptors located on the plasma membrane, S1P can also act intracellularly, independently of S1P1-5, affecting calcium homeostasis and cell proliferation. The SphKs /S1P /S1PL metabolic pathway is implicated in numerous human pathologies including respiratory disorders, thereby raising the possibility that manipulating intracellular S1P levels could offer therapeutic potential in ameliorating lung diseases. This review focuses on the prospects of targeting S1P signaling and S1P metabolizing enzymes using small molecule inhibitors, receptor agonists, and antagonists in the treatment of lung diseases.

Emodin ameliorates bleomycin-induced pulmonary fibrosis in rats by suppressing epithelial-mesenchymal transition and fibroblast activation

Aberrant activation of TGF-β1 is frequently encountered and promotes epithelial-mesenchymal transition (EMT) and fibroblast activation in pulmonary fibrosis. The present study investigated whether emodin mediates its effect via suppressing TGF-β1-induced EMT and fibroblast activation in bleomycin (BLM)-induced pulmonary fibrosis in rats. Here, we found that emodin induced apoptosis and inhibited cellular proliferation, migration and differentiation in TGF-β1-stimulated human embryonic lung fibroblasts (HELFs). Emodin suppressed TGF-β1-induced EMT in a dose- and time-dependent manner in alveolar epithelial A549 cells. Emodin also inhibited TGF-β1-induced Smad2, Smad3 and Erk1/2 activation, suggesting that Smad2/3 and Erk1/2 inactivation mediated the emodin-induced effects on TGF-β1-induced EMT. Additionally, we provided in vivo evidence suggesting that emodin apparently alleviated BLM-induced pulmonary fibrosis and improved pulmonary function by inhibiting TGF-β1 signaling and subsequently repressing EMT, fibroblast activation and extracellular matrix (ECM) deposition. Taken together, our data suggest that emodin mediates its effects mainly via inhibition of EMT and fibroblast activation and thus has a potential for the treatment of pulmonary fibrosis.

C-type natriuretic peptide ameliorates pulmonary fibrosis by acting on lung fibroblasts in mice

Background

Pulmonary fibrosis has high rates of mortality and morbidity; however, no effective pharmacological therapy has been established. C-type natriuretic peptide (CNP), a member of the natriuretic peptide family, selectively binds to the transmembrane guanylyl cyclase (GC)-B receptor and exerts anti-inflammatory and anti-fibrotic effects in various organs through vascular endothelial cells and fibroblasts that have a cell-surface GC-B receptor. Given the pathophysiological importance of fibroblast activation in pulmonary fibrosis, we hypothesized that the anti-fibrotic and anti-inflammatory effects of exogenous CNP against bleomycin (BLM)-induced pulmonary fibrosis were exerted in part by the effect of CNP on pulmonary fibroblasts.

Methods

C57BL/6 mice were divided into two groups, CNP-treated (2.5 μg/kg/min) and vehicle, to evaluate BLM-induced (1 mg/kg) pulmonary fibrosis and inflammation. A periostin-CNP transgenic mouse model exhibiting CNP overexpression in fibroblasts was generated and examined for the anti-inflammatory and anti-fibrotic effects of CNP via fibroblasts in vivo. Additionally, we assessed CNP attenuation of TGF-β-induced differentiation into myofibroblasts by using immortalized human lung fibroblasts stably expressing GC-B receptors. Furthermore, to investigate whether CNP acts on human lung fibroblasts in a clinical setting, we obtained primary-cultured fibroblasts from surgically resected lungs of patients with lung cancer and analyzed levels of GC-B mRNA transcription.

Results

CNP reduced mRNA levels of the profibrotic cytokines interleukin (IL)-1β and IL-6, as well as collagen deposition and the fibrotic area in lungs of mice with bleomycin-induced pulmonary fibrosis. Furthermore, similar CNP effects were observed in transgenic mice exhibiting fibroblast-specific CNP overexpression. In cultured-lung fibroblasts, CNP treatment attenuated TGF-β–induced phosphorylation of Smad2 and increased mRNA and protein expression of α-smooth muscle actin and SM22α, indicating that CNP suppresses fibroblast differentiation into myofibroblasts. Furthermore, human lung fibroblasts from patients with or without interstitial lung disease substantially expressed GC-B receptor mRNA.

Conclusions

These data suggest that CNP ameliorates bleomycin-induced pulmonary fibrosis by suppressing TGF-β signaling and myofibroblastic differentiation in lung fibroblasts. Therefore, we propose consideration of CNP for clinical application to pulmonary fibrosis treatment.