Idiopathic pulmonary fibrosis: Diagnosis, epidemiology and natural history

Thyroid hormone: a resurgent treatment for an emergent concern

The story of thyroid hormone in human physiology is one of mixed emotions. Studying past literature on its use leads one to believe that it serves only a few functions in a handful of diseases. In reality, the pathophysiological role of thyroid hormone is an uncharted expanse. Over the past few decades, research on thyroid hormone has been understandably monopolized by studies of hypo- and hyperthyroidism and cancers. However, in our focused pursuit, we have neglected to observe its role in systems that are not so easily relatable. Recent evidence in lung disease suggests that the thyroid hormone is capable of preserving mitochondria in an indirect manner. This is an exciting revelation given the profound implications of mitochondrial dysfunction in several lung diseases. When paired with known links between thyroid hormone and fibrotic pathways, thyroid hormone-based therapies become more enticing for research. In this article, we inspect the sudden awareness surrounding thyroid hormone and discuss why it is of paramount importance that further studies scrutinize the potential of thyroid hormone, and/or thyromimetics, as therapies for lung diseases.

Bleomycin-enhanced alternative splicing of fibroblast growth factor receptor 2 induces epithelial to mesenchymal transition in lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is an important public health problem, and it has few treatment options given its poorly understood etiology; however, epithelial to mesenchymal transition (EMT) of pneumocytes has been implicated as a factor. Herein, we aimed to explore the underlying mechanisms of lung fibrosis mediated by EMT, with a focus on the alternative splicing of fibroblast growth factor receptor 2 (FGFR2), using bleomycin (BLM)-induced lung fibrotic and transgenic mouse models. We employed BLM-induced and surfactant protein C (SPC)-Cre and LacZ double transgenic mouse models. The results showed that EMT occurred during lung fibrosis. BLM inhibited the expression of epithelial splicing regulatory protein 1 (ESRP1), resulting in enhanced alternative splicing of FGFR2 to the mesenchymal isoform IIIc. BLM-induced lung fibrosis was also associated with the activation of TGF-β/Smad signaling. These findings have implications for rationally targetted strategies to therapeutically address IPF.

Idiopathic pulmonary fibrosis in West Highland white terriers: An update

Canine idiopathic pulmonary fibrosis (CIPF) affects middle-aged to older dogs of a single breed, mainly the West Highland white terrier (WHWT), which is suggestive of a genetic predisposition. CIPF causes exercise intolerance, restrictive dyspnoea and coughing. Coarse crackles are heard on thoracic auscultation. Abnormal blood gas parameters and a shortened '6-min-walking test' distance are common; secondarily induced pulmonary hypertension and/or airway collapse are frequent. These features of CIPF mimic those of idiopathic pulmonary fibrosis (IPF) in humans and therefore identify CIPF as a possible spontaneously arising model for study of human IPF. However, computed tomographic and histopathological findings of CIPF are not identical to those of human IPF. As in human IPF, the aetiology of CIPF is not yet fully elucidated. There are no curative treatments and the prognosis is poor. This paper reviews advances in understanding of the clinical description and natural history of CIPF, the investigation of biomarkers and the exploration of possible aetiologies and mechanistic hypotheses.

Occupational and Environmental Risk Factors for Chronic Fibrosing idiopathic Interstitial Pneumonia in South Korea

OBJECTIVE

We studied the association of occupational and environmental agents with chronic fibrosing idiopathic interstitial pneumonia (IIP) in South Korea.

METHODS

We recruited 92 patients with chronic fibrosing IIP and 92 matched controls who had normal chest radiograph findings by age and gender. We used a structured exposure questionnaire to evaluate potential occupational and environmental risk factors for chronic fibrosing IIP, with adjustments for age, smoking, and clinical risk factors.

RESULTS

We used conditional logistic regression models to analyze associations with chronic fibrosing IIP adjusted for age, smoking and clinical risk factors. Exposure to stone, sand, or silica significantly increased the risk of chronic fibrosing IIP (odds ratio = 5.01; 95% confidence interval, 1.07-24.21) CONCLUSIONS:: Our findings indicate that exposure to stone, sand, and silica might constitute a risk factor for developing chronic fibrosing IIP in the Korean population.

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

Background

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

Methods

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

Results

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

Conclusions

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

Electronic supplementary material

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

Función pulmonar, capacidad funcional y calidad de vida en pacientes con fibrosis pulmonar idiopática. Revisión de la literatura

Introducción. La fibrosis pulmonar idiopática (FPI) es un tipo de enfermedad intersticial, crónica y progresiva que suele manifestarse con disnea y deterioro progresivo de la tolerancia al ejercicio y a las actividades de la vida diaria, llegando a comprometer el nivel psicológico y la interacción social.Objetivos. Seleccionar y sintetizar información acerca de la respuesta de la capacidad funcional, la función pulmonar y la calidad de vida relacionada con la salud en pacientes con FPI luego de ser sometidos a un programa de rehabilitación pulmonar.Materiales y métodos. Revisión de la literatura desde 2000 a 2016, utilizando las bases de datos PubMed y ScienceDirect.Resultados. Se seleccionaron 10 ensayos clínicos randomizados. Se observó tendencia al aumento significativo en la distancia recorrida en test de marcha de 6 minutos. Respecto a la función pulmonar, los resultados variaron entre las poblaciones estudiadas. En la calidad de vida relacionada con la salud se observó mejora en los pacientes sometidos a rehabilitación, pero los niveles de disnea mostraron resultados discordantes.Conclusión. Se evidenciaron beneficios en términos de capacidad funcional y calidad de vida relacionada con la salud, pero los estudios siguen siendo escasos y con poblaciones pequeñas; los efectos de los programas de rehabilitación no se mantienen a los 6 meses de evaluación post-entrenamiento.

Idiopathic pulmonary fibrosis: A guide for nurse practitioners

Idiopathic pulmonary fibrosis (IPF) is a rare disease characterized by decline in lung function, dyspnea, and cough. The clinical course of IPF is variable and unpredictable. Early referral to specialists is key to ensure timely and accurate diagnosis. Two antifibrotic drugs (nintedanib and pirfenidone) have been approved for the treatment of IPF.

Idiopathic pulmonary fibrosis (IPF) is a rare disease characterized by decline in lung function, dyspnea, and cough. The clinical course of IPF is variable and unpredictable. Early referral to specialists is key to ensure timely and accurate diagnosis. Two antifibrotic drugs (nintedanib and pirfenidone) have been approved for the treatment of IPF.

A Serological Biomarker of Versican Degradation is Associated with Mortality Following Acute Exacerbations of Idiopathic Interstitial Pneumonia

Background

Idiopathic interstitial pneumonia (IIP) is characterized by an increased rate of extracellular matrix (ECM) remodeling resulting in fibrosis. Acute exacerbations of IIP represent periods of increased disease activity, thus we hypothesized that ECM remodeling was altered during acute exacerbations and investigated this by serological neo-epitope biomarkers.

Methods

Patients who were sequentially admitted to the hospital with acute exacerbations of IIP were retrospectively analyzed for ECM remodeling at time of exacerbation (AE-IIP) and at clinical stability (S-IIP). Biomarkers released by matrix metalloproteinase-mediated degradation of collagen type I (C1M), III (C3M), IV (C4M), and VI (C6M), elastin (ELM7), versican (VCANM), biglycan (BGM), and C-reactive protein (CRPM) were assessed in serum by competitive ELISAs utilizing neo-epitope specific monoclonal antibodies.

Results

Sixty-eight patients at AE-IIP and 29 at S-IIP were included in this retrospective analysis. Of these, 28 and 11 patients, respectively, had idiopathic pulmonary fibrosis. At AE-IIP, serum levels of C4M (p = 0.002) and C6M (p = 0.024) were increased as compared with S-IIP, while ELM7 (p = 0.024) and VCANM (p < 0.0001) were decreased. Lower VCANM levels at AE-IIP were associated with increased risk of mortality (HR 0.64 [95% CI 0.43–0.94], p = 0.022).

Conclusions

The ECM remodeling profile was significantly altered during acute exacerbations of IIP, and a biomarker of versican degradation was related to mortality outcome. These results indicate that biomarkers of ECM remodeling may be useful in the non-invasive evaluation of acute exacerbations of IIP. Especially versican degradation, as measured serologically by VCANM, may have prognostic potential and help guide treatment for acute exacerbations.

Chitosan-alginate nano-carrier for transdermal delivery of pirfenidone in idiopathic pulmonary fibrosis

Pirfenidone (PFD) is one of the pyridine family components with anti-inflammatory, antifibrotic effects and US FDA approved for the treatment of idiopathic pulmonary fibrosis (IPF). Presently, PFD is administered orally and this has setbacks. Hence, it is important to eliminate the pharmacotherapeutic limitations of PFD. This research was carried out to study the possibility of transdermal delivery of PFD using chitosan-sodium alginate nanogel carriers. In order to synthesize chitosan-sodium alginate nanoparticles loaded with PFD, the pre-gelation method was used. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR) analyses were used for the characterization. Drug encapsulation and release manner were studied using UV spectroscopy. Ex vivo permeation examinations were performed using Franz diffusion cell and fluorescence microscopy. The results showed that nanoparticles having spherical morphology and size in the range of 80 nm were obtained. In vitro drug release profile represents sustained release during 24 h, while 50% and 94% are the loading capacity and efficiency, respectively. Also, the skin penetration of PFD loaded in nanoparticles was significantly increased as compared to PFD solution. The obtained results showed that synthesized nanoparticles can be considered as promising carriers for PFD delivery.

IL-13 induces periostin and eotaxin expression in human primary alveolar epithelial cells: Comparison with paired airway epithelial cells

Alveolar epithelial cells are critical to the pathogenesis of pulmonary inflammation and fibrosis, which are associated with overexpression of type 2 cytokine IL-13. IL-13 is known to induce the production of profibrotic (e.g., periostin) and pro-inflammatory (e.g., eotaxin-3) mediators in human airway epithelial cells, but it remains unclear if human primary alveolar epithelial cells increase periostin and eotaxin expression following IL-13 stimulation. The goals of this study are to determine if alveolar epithelial cells increase periostin and eotaxin expression upon IL-13 stimulation, and if alveolar and airway epithelial cells from the same subjects have similar responses to IL-13. Paired alveolar and airway epithelial cells were isolated from donors without any lung disease, and cultured under submerged or air-liquid interface conditions with or without IL-13. Up-regulation of periostin protein and mRNA was observed in IL-13-stimulated alveolar epithelial cells, which was comparable to that in IL-13-stimulated paired airway epithelial cells. IL-13 also increased eotaxin-3 expression in alveolar epithelial cells, but the level of eotaxin mRNA was lower in alveolar epithelial cells than in airway epithelial cells. Our findings demonstrate that human alveolar epithelial cells are able to produce periostin and eotaxin in responses to IL-13 stimulation. This study suggests the need to further determine the contribution of alveolar epithelial cell-derived mediators to pulmonary fibrosis.

Trends in mortality from idiopathic pulmonary fibrosis in the European Union: an observational study of the WHO mortality database from 2001-2013

Idiopathic pulmonary fibrosis (IPF) is the most common of the idiopathic interstitial pneumonias and is characterised by progressive accumulation of scar tissue in the lungs. The objective of this study was to describe the current mortality rates due to IPF in Europe, based on the World Health Organization (WHO) mortality database.We used country-level data for IPF mortality, identified in the WHO mortality database using International Classification of Diseases 10th Edition (ICD-10) codes, for the period 2001-2013. Joinpoint analysis was performed to describe trends throughout the observation period.The median mortality was 3.75 per 100 000 (interquartile range (IQR) 1.37-5.30) and 1.50 per 100 000 (IQR 0.65-2.02) for males and females, respectively. IPF mortality increased in the majority of the European Union (EU) countries with the exceptions of Denmark, Croatia, Austria and Romania. There was a significant disparity in rates across Europe, in the range 0.41-12.1 per 100 000 for men and 0.24-5.63 per 100 000 for women. The most notable increases were observed in the United Kingdom and Finland. Rates were also substantially higher in males, with sex disparity increasing across the period.The reported IPF mortality appears to be increasing across the EU; however, there is substantial variation in mortality trends and overall reported mortality rates between countries.

Thyroid hormone inhibits lung fibrosis in mice by improving epithelial mitochondrial function

Thyroid hormone (TH) is critical for the maintenance of cellular homeostasis during stress responses, but its role in lung fibrosis is unknown. Here we found that the activity and expression of iodothyronine deiodinase 2 (DIO2), an enzyme that activates TH, were higher in lungs from patients with idiopathic pulmonary fibrosis than in control individuals and were correlated with disease severity. We also found that Dio2-knockout mice exhibited enhanced bleomycin-induced lung fibrosis. Aerosolized TH delivery increased survival and resolved fibrosis in two models of pulmonary fibrosis in mice (intratracheal bleomycin and inducible TGF-β1). Sobetirome, a TH mimetic, also blunted bleomycin-induced lung fibrosis. After bleomycin-induced injury, TH promoted mitochondrial biogenesis, improved mitochondrial bioenergetics and attenuated mitochondria-regulated apoptosis in alveolar epithelial cells both in vivo and in vitro. TH did not blunt fibrosis in Ppargc1a- or Pink1-knockout mice, suggesting dependence on these pathways. We conclude that the antifibrotic properties of TH are associated with protection of alveolar epithelial cells and restoration of mitochondrial function and that TH may thus represent a potential therapy for pulmonary fibrosis.

Long-Term Effects of TCM Yangqing Kangxian Formula on Bleomycin-Induced Pulmonary Fibrosis in Rats via Regulating Nuclear Factor-κB Signaling

Objective

We aimed to evaluate the therapeutic effects and long-term effects of YKF and dissect the potential mechanisms.

Materials and Methods

IPF rats were given YKF, prednisone, or pirfenidone, respectively, from day 1 to day 42, followed by a 28-day nonintervention interval through day 70. Forced vital capacity (FVC), histopathology, hydroxyproline (HYP) contents, lung coefficient, blood inflammatory cell populations, inflammatory cytokine levels of the lung tissues, and the expression of proteins involved in nuclear factor- (NF-) κB signaling pathway were evaluated on days 7, 14, 28, 42, and 70.

Results

HYP contents, Ashcroft scores, lung coefficient, and pulmonary fibrosis blood cell populations increased significantly in IPF rats, while FVC declined. All the above-mentioned parameters were improved in treatment groups from day 7 up to day 70, especially in YKF group. The mRNA and protein expressions of tumor necrosis factor- (TNF-) α significantly decreased, while interferon- (IFN-) γ significantly increased, and phosphorylations of cytoplasm inhibitor of nuclear factor kappa-B kinase β (IKKβ), inhibitor of nuclear factor kappa-B α (IκBα), and NF-κB were obviously downregulated in YKF group from day 7 to day 70.

Conclusion

YKF has beneficial protective and long-term effects on pulmonary fibrosis by anti-inflammatory response and alleviating fibrosis.

Novel insights in cough and breathing patterns of patients with idiopathic pulmonary fibrosis performing repeated 24-hour-respiratory polygraphies

Background

The main symptoms of patients with idiopathic pulmonary fibrosis (IPF) are cough and dyspnea. IPF leads to a restrictive lung disorder impacting daytime and nocturnal breathing patterns. In this pilot study we assessed the course of day- and nighttime respiration, oxygenation, and cough over a period of 8 months as well as differences between wakefulness and sleep in IPF patients.

Methods

Repetitive 24-h respiratory polygraphies (RP) and pulmonary function tests were performed at baseline and after 3, 4, 7 and 8 months. Cough-index, oxygenation parameters (SpO2, time with SpO2 < 90%, desaturation index), respiratory rate and heart rate were assessed for differences between wakefulness and sleep. The first and the last RP were compared to identify changes of these parameters over time. Statistical analyses were performed with Wilcoxon signed rank tests.

Results

Nine IPF patients (8 male, median age 67 years (IQR 60, 77) with 37 valid 24-h RPs were included. Eight patients (88.9%) received antifibrotic treatment. Cough was more prevalent during wakefulness with a median cough-index of 14.8/h (IQR 10.9, 16.8) and 1.6/h (IQR 1.3–2.8) during sleep, p = 0.0039. Oxygenation parameters showed no difference, while respiratory- and heart rate were significantly higher during wakefulness. Despite stable pulmonary function tests over 8 months, the initially elevated respiratory rate increased further during wakefulness (baseline RR median 25.7/min (IQR 19.8, 26.6) vs. RR median 32.2/min (IQR 26.5, 40.9) at follow-up, p = 0.0273). The other respiratory parameters remained stable over time.

Conclusion

Cough in IPF patients is more prevalent during wakefulness than during sleep. Further studies with a larger sample size and longer a follow-up period are needed to evaluate the role of the respiratory rate during wakefulness as a potential clinical follow up parameter in IPF.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0674-y) contains supplementary material, which is available to authorized users.

The role of TRPV4 in fibrosis

The transient receptor potential vanilloid 4 (TRPV4) is a highly Ca²⁺-permeable non-selective cation channel in TRPV family. Accumulating evidence hints that TRPV4 play a significant role in a wide diversity of pathologic changes. Fibrosis is a kind of chronic disease which was characterized by the formation of excessive accumulation of extracellular matrix (ECM) components in tissues and organs. In recent years, a growing body of studies showed that TRPV4 acted as a crucial regulator in the progression of fibrosis including myocardial fibrosis, cystic fibrosis, pulmonary fibrosis, hepatic fibrosis and pancreatic fibrosis, suggesting TRPV4 may be a potential therapeutic vehicle in fibrotic diseases. However, the mechanisms by which TRPV4 regulates fibrosis are still undefined. In this review, firstly, we intend to sum up the collective knowledge of TRPV4. Then we provided the latent mechanism between TRPV4 and fibrosis. We also elaborated the distinct signaling pathways focus on TRPV4 with fibrosis. Finally, we discussed its potential as a novel therapeutic target for fibrosis.

Overexpression of OSM and IL-6 impacts the polarization of pro-fibrotic macrophages and the development of bleomycin-induced lung fibrosis

Although recent evidence indicates that gp130 cytokines, Oncostatin M (OSM) and IL-6 are involved in alternative programming of macrophages, their role in lung fibrogenesis is poorly understood. Here, we investigated the effect of transient adenoviral overexpression of OSM or IL-6 in mice during bleomycin-induced lung fibrosis. Lung fibrosis and M2-like macrophage accumulation were assessed by immunohistochemistry, western blotting, gene expression and flow cytometry. Ex-vivo isolated alveolar and bone marrow-derived macrophages were examined for M2-like programming and signalling. Airway physiology measurements at day 21 demonstrated that overexpression of OSM or IL-6 exacerbated bleomycin-induced lung elastance, consistent with histopathological assessment of extracellular matrix and myofibroblast accumulation. Flow cytometry analysis at day 7 showed increased numbers of M2-like macrophages in lungs of mice exposed to bleomycin and OSM or IL-6. These macrophages expressed the IL-6Rα, but were deficient for OSMRβ, suggesting that IL-6, but not OSM, may directly induce alternative macrophage activation. In conclusion, the gp130 cytokines IL-6 and OSM contribute to the accumulation of profibrotic macrophages and enhancement of bleomycin-induced lung fibrosis. This study suggests that therapeutic strategies targeting these cytokines or their receptors may be beneficial to prevent the accumulation of M2-like macrophages and the progression of fibrotic lung disease.

Beneficial effects of bile acid receptor agonists in pulmonary disease models

INTRODUCTION

Bile acids act as steroid hormones, controlling lipid, glucose and energy metabolism, as well as inflammation and fibrosis. Their actions are implemented through activation of nuclear (FXR, VDR, PXR) and membrane G protein-coupled (TGR5, S1PR2) receptors. Areas covered: This review discusses the potential of FXR and TGR5 as therapeutic targets in the treatment of pulmonary disorders linked to metabolism and/or inflammation. Obeticholic acid (OCA) is the most clinically advanced bile acid-derived agonist for FXR-mediated anti-inflammatory and anti-fibrotic effects. It therefore represents an attractive pharmacological approach for the treatment of lung conditions characterized by vascular and endothelial dysfunctions. Expert opinion: Inflammation, vascular remodeling and fibrotic processes characterize the progression of pulmonary arterial hypertension (PAH) and idiopathic pulmonary fibrosis (IPF). These processes are only partially targeted by the available therapeutic options and still represent a relevant medical need. The results hereby summarized demonstrate OCA efficacy in preventing experimental lung disorders, i.e. monocrotaline-induced PAH and bleomycin-induced fibrosis, by abating proinflammatory and vascular remodeling progression. TGR5 is also expressed in the lung, and targeting the TGR5 pathway, using the TGR5 agonist INT-777 or the dual FXR/TGR5 agonist INT-767, could also contribute to the treatment of pulmonary disorders mediated by inflammation and fibrosis.

Spermidine-mediated poly(lactic-co-glycolic acid) nanoparticles containing fluorofenidone for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a progressive, fatal lung disease with poor survival. The advances made in deciphering this disease have led to the approval of different antifibrotic molecules, such as pirfenidone and nintedanib. An increasing number of studies with particles (liposomes, nanoparticles [NPs], microspheres, nanopolymersomes, and nanoliposomes) modified with different functional groups have demonstrated improvement in lung-targeted drug delivery. In the present study, we prepared, characterized, and evaluated spermidine (Spd)-modified poly(lactic-co-glycolic acid) (PLGA) NPs as carriers for fluorofenidone (AKF) to improve the antifibrotic efficacy of this drug in the lung. Spd-AKF-PLGA NPs were prepared and functionalized by modified solvent evaporation with Spd and polyethylene glycol (PEG)-PLGA groups. The size of Spd-AKF-PLGA NPs was 172.5±4.3 nm. AKF release from NPs was shown to fit the Higuchi model. A549 cellular uptake of an Spd-coumarin (Cou)-6-PLGA NP group was found to be almost twice as high as that of the Cou-6-PLGA NP group. Free Spd and difluoromethylornithine (DFMO) were preincubated in A549 cells to prove uptake of Spd-Cou-6-PLGA NPs via a polyamine-transport system. As a result, the uptake of Spd-Cou-6-PLGA NPs significantly decreased with increased Spd concentrations in incubation. At higher Spd concentrations of 50 and 500 µM, uptake of Spd-Cou-6-PLGA NPs reduced 0.34- and 0.49-fold from that without Spd pretreatment. After pretreatment with DFMO for 36 hours, cellular uptake of Spd-Cou-6-PLGA NPs reached 1.26-fold compared to the untreated DFMO group. In a biodistribution study, the drug-targeting index of Spd-AKF-PLGA NPs in the lung was 3.62- and 4.66-fold that of AKF-PLGA NPs and AKF solution, respectively. This suggested that Spd-AKF-PLGA NPs accumulated effectively in the lung. Lung-histopathology changes and collagen deposition were observed by H&E staining and Masson staining in an efficacy study. In the Spd-AKF-PLGA NP group, damage was further improved compared to the AKF-PLGA NP group and AKF-solution group. The results indicated that Spd-AKF-PLGA NPs are able to be effective nanocarriers for anti-pulmonary fibrosis therapy.

Exogenous nitric oxide enhances the prophylactic effect of aminoguanidine, a preferred iNOS inhibitor, on bleomycin-induced fibrosis in the lung: Implications for the direct roles of the NO molecule in vivo

OBJECTIVE

Inducible nitric oxide synthase (iNOS) aggravates and endothelial nitric oxide synthase (eNOS) ameliorates fibrosis in the lung. Our previous study demonstrated that aminoguanidine (AG), a preferred iNOS inhibitor, prevents bleomycin-induced injury and fibrosis in the lung. The diethylenetriamine nitric oxide adduct (DETA/NO) is a slow-release NO donor. Here, to clarify the exact role of the nitric oxide (NO) molecule in the pathogenesis of pulmonary fibrosis in vivo, we observed the effects of inhalation of aerosolized DETA/NO on fibrosis in the lungs of bleomycin-exposed rats with AG treatment, including the effects on the myofibroblast number, collagen deposition, peroxynitrite anion (ONOO^-) formation, and injury in the lung.

DESIGN AND METHODS

Rats received a single intratracheal instillation of bleomycin or normal saline (NS) on day 0, followed by a daily intraperitoneal injection of AG or NS from day 1 to day 13. Each group was additionally given a daily inhalation of DETA/NO or placebo from day 1 to day 13. On day 14, half of the rats in each group was euthanized, and plasma nitrite and nitrate (NOx), myofibroblasts, type I collagen, ONOO^- and injury in the lung were estimated by the Griess reaction, western blotting, immunohistochemical staining, sirius red staining, and hematoxylin and eosin (HE) staining, respectively. On day 28, the other half of the rats in each group was euthanized, and the total collagen of the lung was evaluated by hydroxyproline assay.

RESULTS

① At the day 14 time point, AG reduced the plasma NOx level in bleomycin rats, while this drug had no significant effect on sham rats. Inhalation of aerosolized DETA/NO increased the plasma NOx level of bleomycin + AG rats, sham rats and sham + AG rats. However, due to large areas of airspace obliteration in the lungs of bleomycin rats, DETA/NO inhalation had no significant effect on the plasma NOx level in these rats. ② At the day 14 time point, AG reduced ONOO^- formation (marked by nitrotyrosine, NT), injury, myofibroblast number, and type I collagen deposition in the lungs of bleomycin rats, while this drug had no significant impact on the above parameters in the lungs of sham rats. Interestingly, DETA/NO inhalation enhanced the preventive effects afforded by AG on myofibroblast number and type I collagen deposition, but had no significant impact on ONOO^- and injury in lung. ③ At the day 28 time point, because rats were not exposed to DETA/NO after day 13, there was no significant difference of the plasma NOx level in sham rats, sham + AG rats, bleomycin rats, and bleomycin + AG rats between DETA/NO inhalation and placebo inhalation. Interestingly, rats administered both DETA/NO and AG still showed a reduction in total collagen of the entire lung compared to rats administered AG alone at this time point.

CONCLUSIONS

Exogenous NO enhances the prophylactic effect afforded by AG on the myofibroblast number and collagen deposition in the lungs of bleomycin-treated rats in vivo. These results suggest that NO has a direct antifibrotic effect in lungs, except for the formation of ONOO^- in the development of pulmonary fibrosis in vivo.

Impact of interstitial lung disease on mortality of patients with rheumatoid arthritis

To identify the prevalence of interstitial lung disease (ILD) in Korean patients with rheumatoid arthritis (RA) and assess its effect on mortality. A total of 3555 patients with RA, with chest X-ray or chest computed tomography (CT) data at enrollment were extracted from the KORean Observational study Network for Arthritis cohort, a nationwide prospective cohort for patients with RA in Korea. The patients were classified into two groups: (1) an ILD group by chest X-ray or chest CT scan, and (2) a non-ILD group by these modalities. After comparing the characteristics of the groups at enrollment, mortalities were compared using the log-rank test. To explore the impact of ILD on mortality, Cox proportional hazard models were used. Sixty-four patients (1.8%) were identified with ILD. Male and older patients were more common in the ILD group. During a mean follow-up of 24 months, 6 patients (9.4%) in the ILD group and 25 patients (0.7%) in the non-ILD group died; the survival rate was significantly worse in the ILD group (p < 0.01). On adjusted analysis, ILD was significantly associated with increased mortality (HR 7.89, CI 3.16-19.69, p < 0.01); the risk of death in patients with ILD was even higher than in patients with cardiovascular disease (CVD, HR 4.10, CI 1.79-9.37, p < 0.01). The prevalence of ILD was 1.8% in Korean patients with RA. ILD is a major risk factor for mortality in patients with RA.

Inhibition of Cell Apoptosis and Amelioration of Pulmonary Fibrosis by Thrombomodulin

Pulmonary fibrosis is the terminal stage of a group of idiopathic interstitial pneumonias, of which idiopathic pulmonary fibrosis is the most frequent and fatal form. Recent studies have shown that recombinant human thrombomodulin (rhTM) improves exacerbation and clinical outcome of idiopathic pulmonary fibrosis, but the mechanism remains unknown. This study evaluated the mechanistic pathways of the inhibitory activity of rhTM in pulmonary fibrosis. Transgenic mice overexpressing human transforming growth factor-β1 that develop spontaneously pulmonary fibrosis, and wild-type mice treated with bleomycin were used as models of lung fibrosis. rhTM was administered to mice by i.p. injection or by the intranasal route. Therapy with rhTM significantly decreased the concentration of high mobility group box1, interferon-γ, and fibrinolytic markers, the expression of growth factors including transforming growth factor-β1, and the degree of lung fibrosis. rhTM significantly suppressed apoptosis of lung epithelial cells in in vivo and in vitro experiments. The results of the present study demonstrated that rhTM can inhibit bleomycin-induced pulmonary fibrosis and transforming growth factor-β1-driven exacerbation and progression of pulmonary fibrosis, and that apart from its well-recognized anticoagulant and anti-inflammatory properties, rhTM can also suppress apoptosis of lung epithelial cells.

Lung microbiome and host immune tone in subjects with idiopathic pulmonary fibrosis treated with inhaled interferon-γ

Therapies targeting inflammation reveal inconsistent results in idiopathic pulmonary fibrosis (IPF). Aerosolised interferon (IFN)-γ has been proposed as a novel therapy. Changes in the host airway microbiome are associated with the inflammatory milieu and may be associated with disease progression. Here, we evaluate whether treatment with aerosolised IFN-γ in IPF impacts either the lower airway microbiome or the host immune phenotype.

Patients with IPF who enrolled in an aerosolised IFN-γ trial underwent bronchoscopy at baseline and after 6 months. 16S rRNA sequencing of bronchoalveolar lavage fluid (BALF) was used to evaluate the lung microbiome. Biomarkers were measured by Luminex assay in plasma, BALF and BAL cell supernatant. The compPLS framework was used to evaluate associations between taxa and biomarkers.

IFN-γ treatment did not change α or β diversity of the lung microbiome and few taxonomic changes occurred. While none of the biomarkers changed in plasma, there was an increase in IFN-γ and a decrease in Fit-3 ligand, IFN-α2 and interleukin-5 in BAL cell supernatant, and a decrease in tumour necrosis factor-β in BALF. Multiple correlations between microbial taxa common to the oral mucosa and host inflammatory biomarkers were found.

These data suggest that the lung microbiome is independently associated with the host immune tone and may have a potential mechanistic role in IPF.

Lower airway microbiome and immunological tone are associated in IPF, an effect independent of IFN-γ treatmenthttp://ow.ly/cTDo30bsJiN

IL-13 and idiopathic pulmonary fibrosis: Possible links and new therapeutic strategies

The recent advances in the knowledge of immunological aspects of many pulmonary diseases, allowed to identify cells, biological functions, cytokines, and receptors that are preferentially involved in each disease. This is the case of asthma, where IL-13 (together with IL-4) is recognized as a central mediator. The role of IL-13 is strictly related, via complex signaling pathways, to eosinophil recruitment and activation, to mucus secretion, periostin generation and to fibrogenic processes (which are part of the remodeling process). These peculiar roles of IL-13 have suggested the hypothesis of its role in Idiopathic Pulmonary Fibrosis, and consequently of its antagonists in the treatment of such disease. We review herein the immunological roles of IL-13 in asthma and IPF, and the currently ongoing attempts to treat IPF by IL-13 antagonism strategies.

Anti-fibrotic effects of chronic treatment with the selective FXR agonist obeticholic acid in the bleomycin-induced rat model of pulmonary fibrosis

Farnesoid X receptor (FXR) activation by obeticholic acid (OCA) has been demonstrated to inhibit inflammation and fibrosis development in liver, kidney and intestine in multiple disease models. FXR activation has also been demonstrated to suppress the inflammatory response and to promote lung repair after lung injury. This study investigated the protective effects of OCA treatment (3 or 10mg/kg/day) on inflammation, tissue remodeling and fibrosis in the bleomycin-induced pulmonary fibrosis rat model. Effects of OCA treatment on morphological and molecular alterations of the lung, as well as remodeling of the alveoli and the right ventricle were also evaluated. Lung function was assessed by measuring airway resistance to inflation. In the acute phase (7days), bleomycin promoted an initial thickening and fibrosis of the lung interstitium, with upregulation of genes related to epithelial proliferation, tissue remodeling and hypoxia. At 28days, an evident increase in the deposition of collagen in the lungs was observed. This excessive deposition was accompanied by an upregulation of transcripts related to the extracellular matrix (TGFβ1, SNAI1 and SNAI2), indicating lung fibrosis. Administration of OCA protected against bleomycin-induced lung damage by suppressing molecular mechanisms related to epithelial-to-mesenchymal transition (EMT), inflammation and collagen deposition, with a dose-dependent reduction of proinflammatory cytokines such as IL-1β and IL-6, as well as TGF-β1 and SNAI1 expression. Pirfenidone, a recently approved treatment for idiopathic pulmonary fibrosis (IPF), significantly counteracted bleomycin-induced pro-fibrotic genes expression, but did not exert significant effects on IL-1β and IL-6. OCA treatment in bleomycin-challenged rats also improved pulmonary function, by effectively normalizing airway resistance to inflation and lung stiffness in vivo. Results with OCA were similar, or even superior, to those obtained with pirfenidone. In conclusion, our results suggest an important protective effect of OCA against bleomycin-induced lung fibrosis by blunting critical mediators in the pathogenesis of IPF.

The earlier, the better: Impact of early diagnosis on clinical outcome in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a complex disease with a highly variable clinical course and generally poor prognosis. Classified as a rare disease, significant increases in incidence have been recorded worldwide in recent years. Left untreated IPF is extremely debilitating with substantial personal, social and economic implications.

OBJECTIVES

To discuss how IPF is diagnosed and managed in real life clinical practice with particular reference to Italy and to determine how new and effective therapies can be incorporated into a patient-centred management approach in order to improve the lives of patients with IPF.

OUTCOMES

Barriers to early diagnosis are discussed. Cited reasons for delays in diagnosing IPF in Italy include: inherent difficulties in diagnosis; lack of knowledge/awareness of the condition among point-of-contact healthcare professionals; delays in referral to centres of excellence and underestimation of symptoms by both patients and healthcare workers. Valid therapeutic options with demonstrated efficacy in slowing the decline in lung function are now available for patients with IPF. The ASCEND trial confirmed the effects of pirfenidone, approved for the treatment of IPF on the basis of the four phase III trials. Nintedanib, a tyrosine kinase inhibitor that targets the PDGF receptors α/β, FGF receptors 1 to 3, and VEGF receptors 1-3, is approved in the USA and the EU for the treatment of IPF. The TOMORROW and the INPULSIS placebo controlled trials in patients with IPF confirm the efficacy and safety of nintedanib and recent interim analyses endorse its long-term effects in slowing disease progression.

CONCLUSIONS

The importance of early and accurate diagnosis of IPF cannot be underestimated and it is the duty of all healthcare professionals to be vigilant to the symptoms of IPF and to involve a multidisciplinary team in diagnosing and managing IPF early in the course of disease.

Influences of innate immunity, autophagy, and fibroblast activation in the pathogenesis of lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by accumulation of extracellular matrix (ECM) and impaired gas exchange. The pathobiological mechanisms that account for disease progression are poorly understood but likely involve alterations in innate inflammatory cells, epithelial cells, and fibroblasts. Thus we seek to review the most recent literature highlighting the complex roles of neutrophils and macrophages as both promoters of fibrosis and defenders against infection. With respect to epithelial cells and fibroblasts, we review the data suggesting that defective autophagy promotes the fibrogenic potential of both cell types and discuss new evidence related to matrix metalloproteinases, growth factors, and cellular metabolism in the form of lactic acid generation that may have consequences for promoting fibrogenesis. We discuss potential cross talk between innate and structural cell types and also highlight literature that may help explain the limitations of current IPF therapies.