Epidemiology and survival of idiopathic pulmonary fibrosis from national data in Canada

Functional Improvement at One Year in Fibrotic Interstitial Lung Diseases-Prognostic Value of Baseline Biomarkers and Anti-Inflammatory Therapies

BACKGROUND

The clinical spectrum of fibrotic interstitial lung diseases (ILDs) is highly heterogeneous. We aimed to evaluate the prognostic value of widely available baseline biomarkers for the improvement of lung function in patients with fibrotic ILDs.

METHODS

This registry-based study included 142 patients with fibrotic ILDs as defined by the presence of reticulation, traction bronchiectasis or honeycombing on initial high-resolution computed tomography (HRCT). Functional improvement at 1 year was defined as a relative increase of 5% in forced vital capacity (FVC) or of 10% in diffusion capacity for carbon monoxide (DLCO). The prognostic value of baseline biomarkers was evaluated for all patients and the subgroup with anti-inflammatory treatment.

RESULTS

At one year, 44 patients showed improvement while 73 showed disease progression. Multivariate analyses found prognostic significance for age < 60 years (OR 5.4; 95%CI 1.9-15.4; p = 0.002), lactate dehydrogenase (LDH) >250 U/L (OR 2.5; 95%CI 1.1-5.8; p = 0.043) and blood monocyte count < 0.8 G/L (OR 3.5; 95%CI 1.1-11.3; p = 0.034). In 84 patients undergoing anti-inflammatory treatment, multivariate analysis revealed age < 60 years (OR 8.5 (95%CI 2.1-33.4; p = 0.002) as the only significant variable.

CONCLUSION

Younger age, a higher LDH and lower blood monocyte count predicted functional improvement in fibrotic ILD patients, while in those treated with anti-inflammatory drugs, only age had significant implications.

Dynamic 3D in vitro lung models: applications of inorganic nanoparticles for model development and characterization

Being a vital organ exposed to the external environment, the lung is susceptible to a plethora of pathogens and pollutants. This is reflected in high incidences of chronic respiratory diseases, which remain a leading cause of mortality world-wide and pose a persistent global burden. It is thus of paramount importance to improve our understanding of these pathologies and provide better therapeutic options. This necessitates the development of representative and physiologically relevant in vitro models. Advances in bioengineering have enabled the development of sophisticated models that not only capture the three-dimensional architecture of the cellular environment but also incorporate the dynamics of local biophysical stimuli. However, such complex models also require novel approaches that provide reliable characterization. Within this review we explore how 3D bioprinting and nanoparticles can serve as multifaceted tools to develop such dynamic 4D printed in vitro lung models and facilitate their characterization in the context of pulmonary fibrosis and breast cancer lung metastasis.

Interstitial Lung Disease and Progressive Pulmonary Fibrosis: a World Trade Center Cohort 20-Year Longitudinal Study

PURPOSE

World Trade Center (WTC) exposure is associated with obstructive airway diseases and sarcoidosis. There is limited research regarding the incidence and progression of non-sarcoidosis interstitial lung diseases (ILD) after WTC-exposure. ILD encompasses parenchymal diseases which may lead to progressive pulmonary fibrosis (PPF). We used the Fire Department of the City of New York's (FDNY's) WTC Health Program cohort to estimate ILD incidence and progression.

METHODS

This longitudinal study included 14,525 responders without ILD prior to 9/11/2001. ILD incidence and prevalence were estimated and standardized to the US 2014 population. Poisson regression modeled risk factors, including WTC-exposure and forced vital capacity (FVC), associated with ILD. Follow-up time ended at the earliest of incident diagnosis, end of study period/case ascertainment, transplant or death.

RESULTS

ILD developed in 80/14,525 FDNY WTC responders. Age, smoking, and gastroesophageal reflux disease (GERD) prior to diagnosis were associated with incident ILD, though FVC was not. PPF developed in 40/80 ILD cases. Among the 80 cases, the average follow-up time after ILD diagnosis was 8.5 years with the majority of deaths occurring among those with PPF (PPF: n = 13; ILD without PPF: n = 6).

CONCLUSIONS

The prevalence of post-9/11 ILD was more than two-fold greater than the general population. An exposure-response gradient could not be demonstrated. Half the ILD cases developed PPF, higher than previously reported. Age, smoking, and GERD were risk factors for ILD and PPF, while lung function was not. This may indicate that lung function measured after respirable exposures would not identify those at risk for ILD or PPF.

Alveolar epithelial cells of lung fibrosis patients are susceptible to severe virus-induced injury

Patients with pulmonary fibrosis (PF) often experience exacerbations of their disease, characterised by a rapid, severe deterioration in lung function that is associated with high mortality. Whilst the pathobiology of such exacerbations is poorly understood, virus infection is a trigger. The present study investigated virus-induced injury responses of alveolar and bronchial epithelial cells (AECs and BECs, respectively) from patients with PF and age-matched controls (Ctrls). Air-liquid interface (ALI) cultures of AECs, comprising type I and II pneumocytes or BECs were inoculated with influenza A virus (H1N1) at 0.1 multiplicity of infection (MOI). Levels of interleukin-6 (IL-6), IL-36γ and IL-1β were elevated in cultures of AECs from PF patients (PF-AECs, n = 8-11), being markedly higher than Ctrl-AECs (n = 5-6), 48 h post inoculation (pi) (P<0.05); despite no difference in H1N1 RNA copy numbers 24 h pi. Furthermore, the virus-induced inflammatory responses of PF-AECs were greater than BECs (from either PF patients or controls), even though viral loads in the BECs were overall 2- to 3-fold higher than AECs. Baseline levels of the senescence and DNA damage markers, nuclear p21, p16 and H2AXγ were also significantly higher in PF-AECs than Ctrl-AECs and further elevated post-infection. Senescence induction using etoposide augmented virus-induced injuries in AECs (but not viral load), whereas selected senotherapeutics (rapamycin and mitoTEMPO) were protective. The present study provides evidence that senescence increases the susceptibility of AECs from PF patients to severe virus-induced injury and suggests targeting senescence may provide an alternative option to prevent or treat the exacerbations that worsen the underlying disease.

Idiopathic pulmonary fibrosis (IPF): Diagnostic routes using novel biomarkers

Idiopathic pulmonary fibrosis (IPF) diagnosis is still the diagnosis of exclusion. Differentiating from other forms of interstitial lung diseases (ILDs) is essential, given the various therapeutic approaches. The IPF course is now unpredictable for individual patients, although some genetic factors and several biomarkers have already been associated with various IPF prognoses. Since its early stages, IPF may be asymptomatic, leading to a delayed diagnosis. The present review critically examines the recent literature on molecular biomarkers potentially useful in IPF diagnostics. The examined biomarkers are grouped into breath and sputum biomarkers, serologically assessed extracellular matrix neoepitope markers, and oxidative stress biomarkers in lung tissue. Fibroblasts and complete blood count have also gained recent interest in that respect. Although several biomarker candidates have been profiled, there has yet to be a single biomarker that proved specific to the IPF disease. Nevertheless, various IPF biomarkers have been used in preclinical and clinical trials to verify their predictive and monitoring potential.

Residential greenness and incident idiopathic pulmonary fibrosis: A prospective study

BACKGROUND

The impact of residential greenness on incident idiopathic pulmonary fibrosis (IPF) is unknown. We aimed to assess the association between residential greenness and incident IPF, identify underlying pathways, and further evaluate the effect among different genetic subgroups.

METHODS

469,348 participants in the UK Biobank were included and followed until December 2020. Normalized difference vegetation index (NDVI) within 300-, 500-, 1000-, and 1500-m buffers (NDVI300m, NDVI500m, NDVI1000m, and NDVI1500m) were employed as indicators of greenness. The polygenic risk score (PRS) was constructed based on 13 independent SNPs. Cox models were fitted to assess the association of residential greenness with incident IPF. Casual mediation analyses were applied to evaluate potential mediators.

FINDINGS

After a median follow-up of 11.85 years, 1574 IPF cases were identified. We found residential greenness inversely associated with incident IPF. The HRs (95%CIs) for each interquartile increase of NDVI300m, NDVI500m, NDVI1000m, NDVI1500m were 0.93 (0.87, 0.99), 0.92 (0.86, 0.98), 0.89 (0.83, 0.95), and 0.89 (0.83, 0.95), respectively. The association was stronger among individuals with intermediate or high genetic risk. In mediation analyses, the main mediators identified were PM2.5 and NO2, with proportion mediated estimated to be 31.92% and 40.61% respectively for NDVI300m.

INTERPRETATION

Residential greenness was associated with reduced risk of incident IPF.

Advanced 3D In Vitro Lung Fibrosis Models: Contemporary Status, Clinical Uptake, and Prospective Outlooks

Fibrosis has been characterized as a global health problem and ranks as one of the primary causes of organ dysfunction. Currently, there is no cure for pulmonary fibrosis, and limited therapeutic options are available due to an inadequate understanding of the disease pathogenesis. The absence of advanced in vitro models replicating dynamic temporal changes observed in the tissue with the progression of the disease is a significant impediment in the development of novel antifibrotic treatments, which has motivated research on tissue-mimetic three-dimensional (3D) models. In this review, we summarize emerging trends in preparing advanced lung models to recapitulate biochemical and biomechanical processes associated with lung fibrogenesis. We begin by describing the importance of in vivo studies and highlighting the often poor correlation between preclinical research and clinical outcomes and the limitations of conventional cell culture in accurately simulating the 3D tissue microenvironment. Rapid advancement in biomaterials, biofabrication, biomicrofluidics, and related bioengineering techniques are enabling the preparation of in vitro models to reproduce the epithelium structure and operate as reliable drug screening strategies for precise prediction. Improving and understanding these model systems is necessary to find the cross-talks between growing cells and the stage at which myofibroblasts differentiate. These advanced models allow us to utilize the knowledge and identify, characterize, and hand pick medicines beneficial to the human community. The challenges of the current approaches, along with the opportunities for further research with potential for translation in this field, are presented toward developing novel treatments for pulmonary fibrosis.

Brg1/PRMT5 nuclear complex epigenetically regulates FOXO1 in IPF mesenchymal progenitor cells

We have discovered intrinsically fibrogenic mesenchymal progenitor cells (MPCs) in the human idiopathic pulmonary fibrosis (IPF) lung. IPF MPCs display a durably distinct transcriptome, suggesting that they have undergone epigenetic modifications. Prior studies indicate that the chromatin remodeler Brg1 associates with the arginine methyltransferase PRMT5 to epigenetically regulate transcription factors. We hypothesize that a Brg1/PRMT5 nuclear complex epigenetically regulates critical nodes in IPF MPC self-renewal signaling networks. IPF and control MPCs were isolated from primary mesenchymal cell lines established from IPF and control patients. RNA-sequencing identified increased expression of the FOXO1 transcription factor in IPF MPCs compared with controls, a result we confirmed by Q-PCR and Western blot analysis. Immunoprecipitation identified a CD44/Brg1/PRMT5 nuclear complex in IPF MPCs. Chromatin immunoprecipitation assays showed that PRMT5 and its methylation mark H3R2me2 are enriched on the FOXO1 promoter. We show that loss of Brg1 and PRMT5 function decreases FOXO1 expression and impairs IPF MPC self-renewal, and that loss of FOXO1 function decreases IPF MPC self-renewal and expression of the SOX2 and OCT4 stemness markers. Our findings indicate that the FOXO1 gene is overexpressed in IPF MPCs in a CD44/Brg1/PRMT5 nuclear complex-dependent manner. Our data suggest that Brg1 alters chromatin accessibility, enriching PRMT5 occupancy on the FOXO1 promoter, and PRMT5 methylates histone H3 arginine 2 (H3R2) on the FOXO1 promoter, increasing its expression. Our data are in accord with the concept that this coordinated interplay is responsible for promoting IPF MPC self-renewal and maintaining a critical pool of fibrogenic MPCs that drive IPF progression.NEW & NOTEWORTHY Our research offers valuable understanding regarding the epigenetic control of IPF MPC. The data we obtained strongly support the idea that the coordination between chromatin remodeling and histone methylation plays a key role in regulating transcription factors. Specifically, our findings indicate that FOXO1, an essential transcription factor, likely governs the self-renewal of IPF MPC, which is crucial for maintaining a critical pool of fibrogenic MPCs. This interplay could be an important therapeutic target.

Acute Exacerbation of Idiopathic Pulmonary Fibrosis With Concurrent Cardiac Amyloidosis: A Technetium Pyrophosphate Study

Amyloidosis presents a diagnostic challenge, particularly when concomitant with severe conditions like acute exacerbations of idiopathic pulmonary fibrosis (IPF). In this report, we detail the case of a 73-year-old patient with acute exacerbation of IPF and simultaneous emergence of cardiac amyloidosis. The patient's clinical journey began with persistent exertional dyspnea, progressing to hypoxemia on admission. Chest CT scans showed extensive ground-glass opacities, consolidations, and pre-existing honeycombing-like cysts and reticular shadows, accompanied by a right-sided pleural effusion. The therapeutic strategy for acute exacerbation of IPF encompassed methylprednisolone pulse therapy, tacrolimus, and nintedanib, augmented with intravenous immunoglobulin and recombinant thrombomodulin. Concurrently, heart failure with preserved ejection fraction was managed with a pharmacological trio: empagliflozin, diuretics, and eplerenone. A hypertrophied heart and low limb voltage prompted an investigation for cardiac amyloidosis, which 99mTechnetium pyrophosphate (99mTc-PYP) scintigraphy confirmed, yielding a probable diagnosis. Following steroid tapering, the patient was discharged home. This case prompted an investigation into the potential role of amyloidosis in pulmonary pathology. Our retrospective review of 10 patients, including four with cardiac amyloidosis, who underwent 99mTc-PYP scintigraphy, revealed a nonsignificant yet notable trend of increased pulmonary accumulation in cardiac amyloidosis cases (median (interquartile range): 5.4×104 (5.3-13.1×104) vs. 3.6×104 (2.4-5.1×104), p=0.0667). Notably, the pulmonary counts in this patient exceeded the negative cohort's mean values, hinting at a possible contribution of amyloid deposition to pulmonary pathology. This study, pioneering in evaluating lung field accumulation of 99mTc-PYP in cardiac amyloidosis, may provide novel insights into the influence of amyloidosis on pulmonary conditions.

High S100A9 level predicts poor survival, and the S100A9 inhibitor paquinimod is a candidate for treating idiopathic pulmonary fibrosis

BACKGROUND

S100A9 is a damage-associated molecular pattern protein that may play an important role in the inflammatory response and fibrotic processes. Paquinimod is an immunomodulatory compound that prevents S100A9 activity. Its safety and pharmacokinetics have been confirmed in human clinical trials. In this study, we investigated the effects of paquinimod in preventing the development of lung fibrosis in vivo and examined the prognostic values of circulatory and lung S100A9 levels in patients with idiopathic pulmonary fibrosis (IPF).

METHODS

The expression and localisation of S100A9 and the preventive effect of S100A9 inhibition on fibrosis development were investigated in a mouse model of bleomycin-induced pulmonary fibrosis. In this retrospective cohort study, the S100A9 levels in the serum and bronchoalveolar lavage fluid (BALF) samples from 76 and 55 patients with IPF, respectively, were examined for associations with patient survival.

RESULTS

S100A9 expression was increased in the mouse lungs, especially in the inflammatory cells and fibrotic interstitium, after bleomycin administration. Treatment with paquinimod ameliorated fibrotic pathological changes and significantly reduced hydroxyproline content in the lung tissues of mice with bleomycin-induced pulmonary fibrosis. Additionally, we found that paquinimod reduced the number of lymphocytes and neutrophils in BALF and suppressed endothelial-mesenchymal transition in vivo. Kaplan-Meier curve analysis and univariate and multivariate Cox hazard proportion analyses revealed that high levels of S100A9 in the serum and BALF were significantly associated with poor prognoses in patients with IPF (Kaplan-Meier curve analysis: p=0.037 (serum) and 0.019 (BALF); multivariate Cox hazard proportion analysis: HR=3.88, 95% CI=1.06 to 14.21, p=0.041 (serum); HR=2.73, 95% CI=1.05 to 7.10, p=0.039 (BALF)).

CONCLUSIONS

The present results indicate that increased S100A9 expression is associated with IPF progression and that the S100A9 inhibitor paquinimod is a potential treatment for IPF.

Using Remote Technology to Engage Patients with Interstitial Lung Diseases in a Home Exercise Program: A Pilot Study

INTRODUCTION

The access and compliance of patients with interstitial lung diseases (ILDs) to exercise programs (EPs) remain challenges.

OBJECTIVES

We assessed the dropout rate, intervention completion, compliance with data acquisition and submission, safety, and satisfaction of a home EP delivered via video conference (EPVC group) or self-directed (EPSD group) to patients with ILD. Pre- and post-intervention changes in patient outcomes (dyspnea, fatigue, exercise capacity, lung function, and quality of life) were secondarily explored.

MATERIAL AND METHODS

Groups performed an eight-week virtual EP three times/week. Video conferences were led by a registered respiratory therapist, whereas self-directed exercises were completed following a pre-recorded video. Participants submitted spirometry, heart rate, and SpO2 results weekly to the research team.

RESULTS

Fourteen patients with ILD were equally assigned to the EPVC and EPSD groups, but three from the EPSD group dropped out after the initial assessment (dropout rate of 42.8% in the EPSD group). Eleven patients (mean age of 67 ± 12 years) completed 96.5% of sessions. Compliance with data acquisition and submission was optimal (≥97.6% in both groups), and no adverse events were reported. Changes in overall fatigue severity were significantly different between groups (p = 0.014, Cohen's r = 0.64).

CONCLUSIONS

The results suggest that a structured virtual EP delivered via video conference or pre-recorded video can be feasible, safe, and acceptable for patients with ILD.

Epidemiology of myasthenia gravis in the United States

Introduction

Global studies of epidemiology of myasthenia gravis (MG) have pointed to increasing prevalence of this rare autoimmune disorder affecting the neuromuscular synapse; however, no new data for the USA were available for decades. We aimed to estimate the incidence rate and prevalence of MG in a large-scale insured US population.

Methods

We conducted a population-based retrospective cohort study to estimate the annual incidence and prevalence of MG cases in the USA during 2017. Using a previously validated algorithm, we identified cases of MG in two Truven Health MarketScan databases, which during 2017 included a sample of approximately 20 million commercially insured and Medicare recipients, plus 10 million Medicaid recipients. We report crude incidence and prevalence and calculated age-and sex-standardized estimates for the USA based on the 2017 American Community Survey. We estimated the number of adult cases during 2021 by extrapolating from the stratified estimates to the population size from the 2021 American Community Survey.

Results

From the US commercially/Medicare-insured cohort, we calculated an age-and sex-standardized incidence of 68.5 new cases per million person-years with an adjusted prevalence of 316.4 per million. Within the Medicaid-insured population, similar yet slightly lower numbers emerged: the adjusted incidence was 49.7 new cases per million person-years, and the adjusted prevalence rate was 203.7 cases per million. Given our results, we were able to estimate that there were approximately 82,715 US adults living with MG in 2021 (or an estimated 320.2 cases per million adults in the USA). We observed a strong effect of age and sex when stratifying the identified incidence rate and prevalence, with a pattern of female preponderance among the younger age brackets, a male preponderance for older cases in the commercially/Medicare-insured cohort, and the disease incidence and prevalence steadily increasing with age.

Discussion

Our updated US population-based estimates of MG epidemiology demonstrate an increase in the previously reported incidence and prevalence from over 20 years ago, in keeping with developments in westernized, industrialized countries. Notable findings of steadily increasing prevalence with age, driven by robust increases in elderly males, prompts questions for basic-translational research, therapeutics, and public health.

Osteopontin: an essential regulatory protein in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic lung disease characterized by abnormal proliferation and activation of fibroblasts, excessive accumulation of extracellular matrix (ECM), inflammatory damage, and disrupted alveolar structure. Despite its increasing morbidity and mortality rates, effective clinical treatments for IPF remain elusive. Osteopontin (OPN), a multifunctional ECM protein found in various tissues, has been implicated in numerous biological processes such as bone remodeling, innate immunity, acute and chronic inflammation, and cancer. Recent studies have highlighted the pivotal role of OPN in the pathogenesis of IPF. This review aims to delve into the involvement of OPN in the inflammatory response, ECM deposition, and epithelial-mesenchymal transition (EMT) during IPF, and intends to lay a solid theoretical groundwork for the development of therapeutic strategies for IPF.

QFAE-nB alleviates pulmonary fibrosis by inhibiting the STING pathway in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Pulmonary fibrosis (PF) is an irreversible lung disease that severely affects human respiratory function. Traditionally, the natural plant Quzhou Fructus Arantii (QFA) has therapeutic effects on respiratory diseases. However, the effects and the mechanism of anti-fibrotic have not been elucidated.

AIM OF THE STUDY

In this study, QFAE-nB was extracted from QFA, the aims of this study include understanding the correlation between Bleomycin (BLM)-induced PF and STING pathway in mice, as well as exploring the role and mechanisms of QFAE-nB in the treatment of PF.

MATERIALS AND METHODS

QFAE-nB was extracted from QFA, six main chemical components in QFAE-nB were identified by HPLC-QTOF-MS/MS, and quantitative analysis was conducted by HPLC. qPCR and Western blot were used to verify the molecular mechanism of QFAE-nB, and the anti-fibrotic effect of QFAE-nB was determined by hematoxylin-eosin (HE) staining and Masson staining as well as immunohistochemistry. TREX1-KO and STING-KO mice were used to verify the relationship between STING and PF and the important target action of QFAE-nB.

RESULTS

Six main flavonoids in QFAE-nB were identified as eriocitrin (0.76%), neoeriocitrin (2.79%), narirutin (4.31%), naringin (35.41%), hesperidin (1.74%), and neohesperidin (27.18%). The results showed that BLM-induced PF was associated with its exacerbated release of proinflammatory factors and chemokines in lung tissues. In addition, QFAE-nB alleviated BLM-induced lung fibrosis in mice by inhibiting the activation of the STING signaling pathway and reducing the signal transduction of TBK1-IRF3 and TBK1-NF-κB pathways. Notably, knockout of the TREX1 gene caused massive inflammation and even induced PF in the lung tissues, whereas QFAE-nB effectively alleviated inflammation and reduced PF. The deletion of the STING gene suppressed BLM-induced PF and inflammation, but STING-KO mice treated with QFAE-nB showed even lower expression levels of proinflammatory factors and chemokine.

CONCLUSIONS

The STING pathway plays an important role in PF, and QFAE-nB alleviates PF by mainly targeting the inhibition of the STING pathway to reduce inflammation. Together, the study paves the way for targeting the STING pathway in PF treatment.

Polydatin alleviates bleomycin-induced pulmonary fibrosis and alters the gut microbiota in a mouse model

To investigate the effect and mechanism of polydatin on bleomycin (BLM)-induced pulmonary fibrosis in a mouse model. The lung fibrosis model was induced by BLM. The contents of TNF-α, LPS, IL-6 and IL-1β in lung tissue, intestine and serum were detected by ELISA. Gut microbiota diversity was detected by 16S rDNA sequencing; R language was used to analyse species composition, α-diversity, β-diversity, species differences and marker species. Mice were fed drinking water mixed with four antibiotics (ampicillin, neomycin, metronidazole, vancomycin; antibiotics, ABx) to build a mouse model of ABx-induced bacterial depletion; and faecal microbiota from different groups were transplanted into BLM-treated or untreated ABx mice. The histopathological changes and collagen I and α-SMA expression were determined. Polydatin effectively reduced the degree of fibrosis in a BLM-induced pulmonary fibrosis mouse model; BLM and/or polydatin affected the abundance of the dominant gut microbiota in mice. Moreover, faecal microbiota transplantation (FMT) from polydatin-treated BLM mice effectively alleviated lung fibrosis in BLM-treated ABx mice compared with FMT from BLM mice. Polydatin can reduce fibrosis and inflammation in a BLM-induced mouse pulmonary fibrosis model. The alteration of gut microbiota by polydatin may be involved in the therapeutic effect.

A novel BRD4 degrader, ARV-825, attenuates lung fibrosis through senolysis and antifibrotic effect

BACKGROUND

Recent studies suggest that cellular senescence is related to the pathogenesis of idiopathic pulmonary fibrosis. However, cellular senescence has yet to be targeted therapeutically in clinical practice. ARV825, a recently developed BRD4 degrader, has been reported as a novel senolytic drug. Conversely, it has also been reported that BRD4 regulates the pro-fibrotic gene expression of fibroblasts. Therefore, this study focuses on the senolytic and anti-fibrotic effects of ARV825 and evaluated these effects on lung fibrosis.

METHODS

Lung fibroblasts were induced to senescence through serial passage. The expression of senescence markers and pro-fibrotic markers were determined through quantitative PCR or immunoblot analysis. Lung fibrosis was induced in mice through intratracheal administration of bleomycin. Mice treated with ARV825 underwent histological analysis of lung fibrosis using the Ashcroft score. Total lung collagen was quantified through a hydroxyproline assay. Respiratory mechanics analysis was performed using the flexiVent system.

RESULTS

For senescent cells, ARV825 induced the expression of an apoptosis marker while reducing the expression of BRD4 and senescence markers. On the other hand, for early passage pre-senescent cells, ARV825 reduced the expression of collagen type 1 and α-smooth muscle actin. In an experimental mouse model of lung fibrosis, ARV825 attenuated lung fibrosis and improved lung function. Immunohistochemical staining revealed a significant decrease in the number of senescent alveolar type 2 cells in lung tissue due to ARV825 treatment.

CONCLUSIONS

These results suggest that ARV825 may impact the progressive and irreversible course of fibrotic lung diseases.

Low-level ambient sulfur dioxide exposure and genetic susceptibility associated with incidence of idiopathic pulmonary fibrosis: A national prospective cohort study

BACKGROUND

The association between long-term air pollution exposure and the development of idiopathic pulmonary fibrosis (IPF) has been established, but the evidence regarding the effect of low levels of air pollution, especially ambient sulfur dioxide (SO2), is limited. Besides, the combined effect and interaction between genetic susceptibility and ambient SO2 on IPF remain uncertain.

METHODS

This study retrieved data from 402,042 participants who were free of IPF at baseline in the UK Biobank. The annual mean concentration of ambient SO2 was estimated for each participant based on their residential addresses using a bilinear interpolation method. Cox proportional hazard models were used to examine the relationship between ambient SO2 and incident IPF. We further generated a polygenic risk score (PRS) for IPF and estimated the combined effects of genetic susceptibility and ambient SO2 on incident IPF.

RESULTS

After a median follow-up of 11.78 years, 2562 cases of IPF were identified. The results indicated that each 1 μg/m3 increase in ambient SO2 was associated with a hazard ratio (HR) (95% confidence interval [CI]) of 1.67 (1.58, 1.76) for incident IPF. The study found statistically significant synergistic additive interaction between genetic susceptibility and ambient SO2. Individuals with high genetic risk and high ambient SO2 exposure had a higher risk of developing IPF (HR = 7.48, 95% CI:5.66, 9.90).

CONCLUSION

The study suggests that long-term exposure to ambient SO2, even at concentrations lower than current air quality guidelines set by the Word Health Organization and European Union, may be an important risk factor for IPF. This risk is more pronounced among people with a high genetic risk. Therefore, these findings emphasize the need to consider the potential health effects of SO2 exposure and the necessity for stricter air quality standards.

A systematic review of the research progress of traditional Chinese medicine against pulmonary fibrosis: from a pharmacological perspective

Pulmonary fibrosis is a chronic progressive interstitial lung disease caused by a variety of etiologies. The disease can eventually lead to irreversible damage to the lung tissue structure, severely affecting respiratory function and posing a serious threat to human health. Currently, glucocorticoids and immunosuppressants are the main drugs used in the clinical treatment of pulmonary fibrosis, but their efficacy is limited and they can cause serious adverse effects. Traditional Chinese medicines have important research value and potential for clinical application in anti-pulmonary fibrosis. In recent years, more and more scientific researches have been conducted on the use of traditional Chinese medicine to improve or reduce pulmonary fibrosis, and some important breakthroughs have been made. This review paper systematically summarized the research progress of pharmacological mechanism of traditional Chinese medicines and their active compounds in improving or reducing pulmonary fibrosis. We conducted a systematic search in several main scientific databases, including PubMed, Web of Science, and Google Scholar, using keywords such as idiopathic pulmonary fibrosis, pulmonary fibrosis, interstitial pneumonia, natural products, herbal medicine, and therapeutic methods. Ultimately, 252 articles were included and systematically evaluated in this analysis. The anti-fibrotic mechanisms of these traditional Chinese medicine studies can be roughly categorized into 5 main aspects, including inhibition of epithelial-mesenchymal transition, anti-inflammatory and antioxidant effects, improvement of extracellular matrix deposition, mediation of apoptosis and autophagy, and inhibition of endoplasmic reticulum stress. The purpose of this article is to provide pharmaceutical researchers with information on the progress of scientific research on improving or reducing Pulmonary fibrosis with traditional Chinese medicine, and to provide reference for further pharmacological research.

Topological data analysis identifies molecular phenotypes of idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a debilitating, progressive disease with a median survival time of 3-5 years. Diagnosis remains challenging and disease progression varies greatly, suggesting the possibility of distinct subphenotypes.

METHODS AND RESULTS

We analysed publicly available peripheral blood mononuclear cell expression datasets for 219 IPF, 411 asthma, 362 tuberculosis, 151 healthy, 92 HIV and 83 other disease samples, totalling 1318 patients. We integrated the datasets and split them into train (n=871) and test (n=477) cohorts to investigate the utility of a machine learning model (support vector machine) for predicting IPF. A panel of 44 genes predicted IPF in a background of healthy, tuberculosis, HIV and asthma with an area under the curve of 0.9464, corresponding to a sensitivity of 0.865 and a specificity of 0.89. We then applied topological data analysis to investigate the possibility of subphenotypes within IPF. We identified five molecular subphenotypes of IPF, one of which corresponded to a phenotype enriched for death/transplant. The subphenotypes were molecularly characterised using bioinformatic and pathway analysis tools identifying distinct subphenotype features including one which suggests an extrapulmonary or systemic fibrotic disease.

CONCLUSIONS

Integration of multiple datasets, from the same tissue, enabled the development of a model to accurately predict IPF using a panel of 44 genes. Furthermore, topological data analysis identified distinct subphenotypes of patients with IPF which were defined by differences in molecular pathobiology and clinical characteristics.

A polo-like kinase inhibitor identified by computational repositioning attenuates pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease with few effective therapeutic options. Recently, drug repositioning, which involves identifying novel therapeutic potentials for existing drugs, has been popularized as a new approach for the development of novel therapeutic reagents. However, this approach has not yet been fully utilized in the field of pulmonary fibrosis.

METHODS

The present study identified novel therapeutic options for pulmonary fibrosis using a systematic computational approach for drug repositioning based on integration of public gene expression signatures of drug and diseases (in silico screening approach).

RESULTS

Among the top compounds predicted to be therapeutic for IPF by the in silico approach, we selected BI2536, a polo-like kinase (PLK) 1/2 inhibitor, as a candidate for treating pulmonary fibrosis using an in silico analysis. However, BI2536 accelerated mortality and weight loss rate in an experimental mouse model of pulmonary fibrosis. Because immunofluorescence staining revealed that PLK1 expression was dominant in myofibroblasts while PLK2 expression was dominant in lung epithelial cells, we next focused on the anti-fibrotic effect of the selective PLK1 inhibitor GSK461364. Consequently, GSK461364 attenuated pulmonary fibrosis with acceptable mortality and weight loss in mice.

CONCLUSIONS

These findings suggest that targeting PLK1 may be a novel therapeutic approach for pulmonary fibrosis by inhibiting lung fibroblast proliferation without affecting lung epithelial cells. In addition, while in silico screening is useful, it is essential to fully determine the biological activities of candidates by wet-lab validation studies.

Incidence and prevalence of interstitial lung diseases worldwide: a systematic literature review

Interstitial lung disease (ILD) is a collective term representing a diverse group of pulmonary fibrotic and inflammatory conditions. Due to the diversity of ILD conditions, paucity of guidance and updates to diagnostic criteria over time, it has been challenging to precisely determine ILD incidence and prevalence. This systematic review provides a synthesis of published data at a global level and highlights gaps in the current knowledge base. Medline and Embase databases were searched systematically for studies reporting incidence and prevalence of various ILDs. Randomised controlled trials, case reports and conference abstracts were excluded. 80 studies were included, the most described subgroup was autoimmune-related ILD, and the most studied conditions were rheumatoid arthritis (RA)-associated ILD, systemic sclerosis associated (SSc) ILD and idiopathic pulmonary fibrosis (IPF). The prevalence of IPF was mostly established using healthcare datasets, whereas the prevalence of autoimmune ILD tended to be reported in smaller autoimmune cohorts. The prevalence of IPF ranged from 7 to 1650 per 100 000 persons. Prevalence of SSc ILD and RA ILD ranged from 26.1% to 88.1% and 0.6% to 63.7%, respectively. Significant heterogeneity was observed in the reported incidence of various ILD subtypes. This review demonstrates the challenges in establishing trends over time across regions and highlights a need to standardise ILD diagnostic criteria.PROSPERO registration number: CRD42020203035.

Protective role of baicalin in the dynamic progression of lung injury to idiopathic pulmonary fibrosis: A meta-analysis

BACKGROUND AND PURPOSE

The pathological progression of lung injury (LI) to idiopathic pulmonary fibrosis (IPF) is a common feature of the development of lung disease. At present, effective strategies for preventing this progression are unavailable. Baicalin has been reported to specifically inhibit the progression of LI to IPF. Therefore, this meta-analysis aimed to assess its clinical application and its potential as a therapeutic drug for lung disease based on integrative analysis.

METHODS

We systematically searched preclinical articles in eight databases and reviewed them subjectively. The CAMARADES scoring system was used to assess the degree of bias and quality of evidence, whereas the STATA software (version 16.0 software) was used for statistical analysis, including a 3D analysis of the effects of dosage frequency of baicalin in LI and IPF. The protocol of this meta-analysis is documented in the PROSPERO database (CRD42022356152).

RESULTS

A total of 23 studies and 412 rodents were included after several rounds of screening. Baicalin was found to reduce the levels of TNF-α, IL-1β, IL-6, HYP, TGF-β and MDA and the W/D ratio and increase the levels of SOD. Histopathological analysis of lung tissue validated the regulatory effects of baicalin, and the 3D analysis of dosage frequency revealed that the effective dose of baicalin is 10-200 mg/kg. Mechanistically, baicalin can prevent the progression of LI to IPF by modulating p-Akt, p-NF-κB-p65 and Bcl-2-Bax-caspase-3 signalling. Additionally, baicalin is involved in signalling pathways closely related to anti-apoptotic activity and regulation of lung tissue and immune cells.

CONCLUSION

Baicalin at the dose of 10-200 mg/kg exerts protective effects against the progression of LI to IPF through anti-inflammatory and anti-apoptotic pathways.

Sex- and Race-Based Differences in the Treatment of Interstitial Lung Diseases in North America and Australasia

BACKGROUND

Biological sex, gender, and race are important considerations in patients with interstitial lung diseases (ILDs).

RESEARCH QUESTION

Does a patient's sex assigned at birth, and race, influence ILD treatment initiation?

STUDY DESIGN AND METHODS

Patients with ILD from three longitudinal prospective registries were compared in this observational study. ILD-related medications included antifibrotics and immunomodulating medications. Race was dichotomized as "White" vs "non-White." Time to treatment initiation was determined from the date of the initial ILD registry visit to the date of first medication initiation. Proportions of treated patients were compared between groups by χ2 test. Cox proportional analysis was used to determine how sex and race were associated with time to treatment initiation stratified by ILD diagnosis.

RESULTS

A total of 4,572 patients were included across all cohorts. The proportion of men who received treatment was higher than for women in the Canadian cohort (47% vs 40%; P < .001), and the proportion of White patients who received treatment was also higher compared with non-White patients (46% vs 36%; P < .001). In contrast, the proportion of treated men in the Chicago cohort was lower compared with women (56% vs 64%; P = .005), and that of White patients was lower compared with non-White patients (56% vs 69%; P < .001). No sex- or race-based differences in proportions of patients treated were found in the Australasian cohort. White race was significantly associated with earlier treatment initiation compared with non-White race across diagnoses in the Canadian cohort, whereas the opposite association was found in the Australasian cohort.

INTERPRETATION

Sex- and race-based differences exist in the initiation of ILD treatment, with variability across different cohorts in different countries. Reasons for these differences need to be further explored in future studies.

Tanreqing injection protects against bleomycin-induced pulmonary fibrosis via inhibiting STING-mediated endoplasmic reticulum stress signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Idiopathic pulmonary fibrosis (IPF), characterized by excessive collagen deposition, is a progressive and typically fatal lung disease without effective therapeutic methods. Tanreqing injection (TRQ), a Traditional Chinese Patent Medicine, has been widely used to treat inflammatory respiratory diseases clinically.

AIM OF THE STUDY

The present work aims to elucidate the therapeutic effects and the possible mechanism of TRQ against pulmonary fibrosis.

METHODS

The pulmonary fibrosis murine model were constructed by the intratracheal injection of bleomycin (BLM). 7 days later, TRQ-L (2.6 ml/kg) and TRQ-H (5.2 ml/kg) were administered via intraperitoneal injection respectively for 21 days. The efficacy and underlying molecular mechanism of TRQ were investigated.

RESULTS

Here, we showed that TRQ significantly inhibited BLM-induced lung edema and pulmonary function. TRQ markedly reduced BLM-promoted inflammatory cell infiltration in BALF and inflammatory cytokines release (TNF-α, IL-6, and IL-1β) in serum and lung tissues. Meanwhile, TRQ also alleviated BLM-induced collagen synthesis and deposition. Simultaneously, TRQ attenuated BLM-induced pulmonary fibrosis through regulating the expression of fibrotic hallmarks, manifested by down-regulated α-SMA and up-regulated E-cadherin. Moreover, we found that TRQ significantly prevented STING, p-P65, BIP, p-PERK, p-eIF2α, and ATF4 expression in lung fibrosis mice.

CONCLUSIONS

Taken together, our results indicated that TRQ positively affects inflammatory responses and lung fibrosis by regulating STING-mediated endoplasmic reticulum stress (ERS) signal pathway.

Nationwide epidemiologic study for fibrosing interstitial lung disease (F-ILD) in South Korea: a population-based study

BACKGROUND

Fibrosing interstitial lung disease (F-ILD) is a major public health concern due to its poor prognosis. Recent clinical evidence shows that antifibrotic approaches such as pirfenidone and nintedanib provide better clinical outcome prediction in idiopathic pulmonary fibrosis (IPF) as well as selected progressive fibrosing ILD (PF-ILD) patients. Having epidemiologic insight into these diseases will be essential for the efficient utilization of these therapeutic resources. This study aimed to estimate the current prevalence, incidence, and mortality of F-ILD classified as idiopathic pulmonary fibrosis (IPF), PF-ILD other than IPF, and non-progressive F-ILD and their temporal trend in Korea.

METHODS

Population-based retrospective cohort study was conducted using the Korean Health Insurance Review and Assessment (HIRA) database (2011-2018). Patients with IPF were identified using ICD-10 code, RID code, and differential diagnosis approach. By leveraging medical records available from claim data and referencing those used in clinical trials, rigorous diagnostic criteria for PF-ILD detection were implemented.

RESULTS

For the past eight years, the prevalence of IPF and PF-ILD has progressively increased, while non-progressive F-ILD has remained stable. IPF, PF-ILD, and non-progressive F-ILD prevalence per 100,000 in 2018 were 16.9, 10.4, and 11.7, respectively. The incidence of IPF in 2018 was more than twice that of 2012. The incidence of PF-ILD in 2018 was 1.5 times higher than that in 2012. In 2018, the mortalites were 10.3% and 12.2% for IPF and PF-ILD, respectively. The mortality rate of PF-ILD was greater than that of IPF in all years. Unclassifiable PF-ILD and rheumatoid arthritis-PF-ILD had the highest proportion and mortality among the PF-ILD subtypes.

CONCLUSION

The prevalence and incidence of IPF and PF-ILD have been steadily increasing in recent years. The mortality rate of PF-ILD remained consistently high and exceeded those of IPF in all years.

Therapeutic strategies targeting pro-fibrotic macrophages in interstitial lung disease

Idiopathic pulmonary fibrosis (IPF) is the representative phenotype of interstitial lung disease where severe scarring develops in the lung interstitium. Although antifibrotic treatments are available and have been shown to slow the progression of IPF, improved therapeutic options are still needed. Recent data indicate that macrophages play essential pro-fibrotic roles in the pathogenesis of pulmonary fibrosis. Historically, macrophages have been classified into two functional subtypes, "M1" and "M2," and it is well described that "M2" or "alternatively activated" macrophages contribute to fibrosis via the production of fibrotic mediators, such as TGF-β, CTGF, and CCL18. However, highly plastic macrophages may possess distinct functions and phenotypes in the fibrotic lung environment. Thus, M2-like macrophages in vitro and pro-fibrotic macrophages in vivo are not completely identical cell populations. Recent developments in transcriptome analysis, including single-cell RNA sequencing, have attempted to depict more detailed phenotypic characteristics of pro-fibrotic macrophages. This review will outline the role and characterization of pro-fibrotic macrophages in fibrotic lung diseases and discuss the possibility of treating lung fibrosis by preventing or reprogramming the polarity of macrophages. We also utilized a systematic approach to review the literature and identify novel and promising therapeutic agents that follow this treatment strategy.

Mass cytometry identifies characteristic immune cell subsets in bronchoalveolar lavage fluid from interstitial lung diseases

Immune cells have been implicated in interstitial lung diseases (ILDs), although their phenotypes and effector mechanisms remain poorly understood. To better understand these cells, we conducted an exploratory mass cytometry analysis of immune cell subsets in bronchoalveolar lavage fluid (BALF) from patients with idiopathic pulmonary fibrosis (IPF), connective-tissue disease (CTD)-related ILD, and sarcoidosis, using two panels including 64 markers. Among myeloid cells, we observed the expansion of CD14⁺ CD36^hi CD84^hiCCR2^- monocyte populations in IPF. These CD14⁺ CD36^hi CD84^hi CCR2^- subsets were also increased in ILDs with a progressive phenotype, particularly in a case of acute exacerbation (AEx) of IPF. Analysis of B cells revealed the presence of cells at various stages of differentiation in BALF, with a higher percentage of IgG memory B cells in CTD-ILDs and a trend toward more FCRL5⁺ B cells. These FCRL5⁺ B cells were also present in the patient with AEx-IPF and sarcoidosis with advanced lung lesions. Among T cells, we found increased levels of IL-2R⁺ TIGIT⁺ LAG3⁺ CD4⁺ T cells in IPF, increased levels of CXCR3⁺ CD226⁺ CD4⁺ T cells in sarcoidosis, and increased levels of PD1⁺ TIGIT⁺ CD57⁺ CD8⁺ T cells in CTD-ILDs. Together, these findings underscore the diverse immunopathogenesis of ILDs.

Exploring the comorbidity mechanisms between asthma and idiopathic pulmonary fibrosis and the pharmacological mechanisms of Bu-Shen-Yi-Qi decoction therapy via network pharmacology

Backgrounds

Asthma and idiopathic pulmonary fibrosis (IPF) are common chronic diseases of the respiratory system in clinical practice. However, the relationship and molecular links remain unclear, and the current treatment’s efficacy is disappointing. Bu-Shen-Yi-Qi (BSYQ) decoction has proven effective in treating various chronic airway inflammatory diseases, including asthma and IPF. But the underlying pharmacological mechanisms are still to be elucidated.

Methods

This study searched the proteins related to asthma and IPF via TTD, CTD, and DisGeNET databases and then submitted to the STRING to establish the protein–protein interaction (PPI) network. The co-bioinformatics analysis was conducted by Metascape. The active ingredients of BSYQ decoction were screened from TCMSP, ETCM, BATMAN-TCM databases, and HPLC/MS experiment. The corresponding targets were predicted based on TCMSP, ETCM, and BATMAN-TCM databases. The shared targets for asthma and IPF treatment were recognized, and further GO and KEGG analyses were conducted with the DAVID platform. Finally, molecule docking via Autodock Vina was employed to predict the potential binding mode between core potential compounds and targets.

Results

Finally, 1333 asthma-related targets and 404 IPF-related proteins were retrieved, 120 were overlapped between them, and many of the asthma-related proteins fall into the same statistically significant GO terms with IPF. Moreover, 116 active ingredients of BSYQ decoction were acquired, and 1535 corresponding targets were retrieved. Eighty-three potential compounds and 56 potential targets were recognized for both asthma and IPF treatment. GO and KEGG analysis indicated that the inflammation response, cytokine production, leukocyte differentiation, oxygen level response, etc., were the common pathological processes in asthma and IPF, which were regulated by BSYQ decoction. Molecule docking further predicted the potential binding modes between the core potential compounds and targets.

Conclusion

The current study successfully clarified the complex molecule links between asthma and IPF and found the potential common targets. Then we demonstrated the efficacy of BSYQ decoction for asthma and IPF treatment from the angle of network pharmacology, which may provide valuable references for further studies and clinical use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03637-7.

Efficacy and safety of traditional Chinese medicine treatment for idiopathic pulmonary fibrosis: An exploratory, randomized, double-blinded and placebo controlled trial

Background and objective: Idiopathic pulmonary fibrosis (IPF) is a critical disease, with limited treatments available. Clinical practices show that traditional Chinese medicine (TCM) has certain efficacy. This study was preliminarily to evaluate the efficacy and safety of TCM treatment based on syndrome differentiation in IPF. Methods: A study design of exploratory, multi-centers, randomized, double-blinded, placebo controlled trial has been adopted. A total of 80 IPF patients from four sub-centers were enrolled. All the patients were randomly assigned into TCM group (TCMG) or control group (CG) in 1:1. Patients in TCMG were given CM granules, as patients in CG given with the placebo of CM granule. All the patients received a 26-week treatment. The efficacy was assessed by acute exacerbations (AEs) of IPF, pulmonary function, clinical symptoms, dyspnea scores (mMRC), health-related quality of life (HRQoL), 6-min walk test (6MWT) and all-cause mortality. Safety has also been assessed. Results: A total of 67 patients completed the trial with 35 in TCM group and 32 in control group. Meaningful differences have been observed in mean changes in AEs (-1.56 times; 95% CI, -2.69 to -0.43, p = 0.01), DLco% (5.29; 95% CI, 0.76 to 9.81, p = 0.02), cough scores (-0.38 points; 95% CI, -0.73 to -0.04, p = 0.03), and 6MWT (30.43 m; 95% CI, 2.85 to 58.00, p = 0.03), with no statistical differences in FEV1, FVC, expectoration, chest tightness, Shortness of breath, Fatigue, Cyanosis, mMRC, CAT, SF-36, and SGRQ total scores in 26 weeks after treatment than before treatment. At of the end of follow-up, a total of 10 patients died, including three and seven in the TCM and control group respectively. And the HR (Hazard ratio) for CM granules in all-cause mortality was 0.39 (95% CI, 0.10-1.52). The drug-related adverse events were not observed. Conclusion: CM granules, as compared with placebo, could reduce frequencies of AEs, improve pulmonary function, HRQoL, exercise capacity and symptoms and signs for IPF to some extent with acceptable side-effect.

Functional Au nanoparticles for engineering and long-term CT imaging tracking of mesenchymal stem cells in idiopathic pulmonary fibrosis treatment

Idiopathic pulmonary fibrosis (IPF) therapy has always been a big and long-standing challenge in clinical practice due to the lack of miraculous medicine. Mesenchymal stem cells (MSCs)-based therapy has recently emerged as a promising candidate for redefining IPF therapy. Enhancing the therapeutic efficacy of MSCs and understanding of their growth, migration and differentiation in harsh lung microenviroments are two keys to improving the stem cell-based IPF treatment. Herein, a non-viral dual-functional nanocarrier is fabricated by a one-pot approach, using protamine sulfate stabilized Au nanoparticles (AuPS), to genetically engineer MSCs for simultaneous IPF treatment and monitoring the biological behavior of the MSCs. AuPS exhibits superior cellular uptake ability, which results in efficient genetic engineering of MSCs to overexpress hepatocyte growth factor for enhanced IPF therapy. In parallel, the intracellular accumulation of AuPS improves the CT imaging contrast of MSCs, allowing visual tracking of the therapeutic engineered MSCs up to 48 days. Overall, this work has described for the first time a novel strategy for enhanced therapeutic efficacy and long-term CT imaging tracking of transplanted MSCs in IPF therapy, providing great prospect for stem cell therapy of lung disease.

Incidence, prevalence, and national burden of interstitial lung diseases in India: Estimates from two studies of 3089 subjects

Background and objective

The epidemiology of interstitial lung diseases (ILDs) in developing countries remains unknown. The objective of this study was to estimate the incidence, prevalence, and national burden of ILDs in India.

Methods

Data of consecutive subjects (aged >12 years) with ILDs included in a registry between March 2015 and February 2020 were analyzed retrospectively. The proportion of each ILD subtype was determined. The crude annual incidence and prevalence of ILDs for our region were estimated. Subsequently, the primary estimates of the national annual incident and prevalent burden of ILD and its subtypes were calculated. Alternative estimates for each ILD subtype were calculated using the current and a large, previous Indian study (n = 1,084). Data were analyzed using SPSS version 22 and are presented descriptively.

Results

A total of 2,005 subjects (mean age, 50.7 years; 47% men) were enrolled. Sarcoidosis (37.3%) was the most common ILD subtype followed by connective tissue disease (CTD)-related ILDs (19.3%), idiopathic pulmonary fibrosis (IPF, 17.0%), and hypersensitivity pneumonitis (HP, 14.4%). The crude annual incidence and prevalence of ILDs were 10.1–20.2 and 49.0–98.1, respectively per 100,000 population. The best primary estimates for the crude national burden of all ILDs, sarcoidosis, CTD-ILD, IPF, HP, and other ILDs (in thousands) were 433–867, 213–427, 75–150, 51–102, 54–109, and 39–78. The respective alternative estimates (in thousands) were sarcoidosis, 127–254; CTD-ILD, 81–162; IPF, 46–91; HP, 130–261; other ILDs, 49–98.

Conclusion

In contrast to developed countries, sarcoidosis and HP are the ILDs with the highest burden in India.

La fibrose pulmonaire idiopathique

La fibrose pulmonaire idiopathique (FPI) est une maladie pulmonaire chronique, évolutive et mortelle dont l’origine est inconnue. Elle se caractérise par une cicatrisation aberrante de l’épithélium alvéolaire aboutissant à une accumulation de matrice extracellulaire (MEC). Les foyers fibroblastiques, constitués de fibroblastes et de myofibroblastes, sont responsables de la production excessive de MEC. Les deux seules molécules thérapeutiques disponibles sur le marché permettent seulement de ralentir l’évolution de la maladie. Dans cette revue, nous présentons les mécanismes impliqués dans la progression de la maladie, ses traitements et les modèles d’étude.

Hsp90 in Human Diseases: Molecular Mechanisms to Therapeutic Approaches

The maturation of hemeprotein dictates that they incorporate heme and become active, but knowledge of this essential cellular process remains incomplete. Studies on chaperon Hsp90 has revealed that it drives functional heme maturation of inducible nitric oxide synthase (iNOS), soluble guanylate cyclase (sGC) hemoglobin (Hb) and myoglobin (Mb) along with other proteins including GAPDH, while globin heme maturations also need an active sGC. In all these cases, Hsp90 interacts with the heme-free or apo-protein and then drives the heme maturation by an ATP dependent process before dissociating from the heme-replete proteins, suggesting that it is a key player in such heme-insertion processes. As the studies on globin maturation also need an active sGC, it connects the globin maturation to the NO-sGC (Nitric oxide-sGC) signal pathway, thereby constituting a novel NO-sGC-Globin axis. Since many aggressive cancer cells make Hbβ/Mb to survive, the dependence of the globin maturation of cancer cells places the NO-sGC signal pathway in a new light for therapeutic intervention. Given the ATPase function of Hsp90 in heme-maturation of client hemeproteins, Hsp90 inhibitors often cause serious side effects and this can encourage the alternate use of sGC activators/stimulators in combination with specific Hsp90 inhibitors for better therapeutic intervention.

Management of BMI Is a Potential New Approach for the Prevention of Idiopathic Pulmonary Fibrosis

Aims: Current idiopathic pulmonary fibrosis (IPF) therapies usually show a poor outcome or treatment efficacy. The search for new risk factors has significant implications in preventing, delaying, and treating IPF. The association between obesity and the risk of IPF is not clear. This study aimed to investigate the role of different obesity types in IPF risk, which provides the possibility of weight loss as a new approach for IPF prevention.

Methods: We conducted a two-sample Mendelian randomization (MR) analysis to assess the causal effect of obesity on IPF risk. We collected summary data of genetically determined obesity-related traits, including body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) from large-scale consortia (the sample size ranging from 232,101 to 681,275), and genetic association with IPF from one of the largest meta-analyses including 2,668 cases. A total of 35–469 single nucleotide polymorphisms were selected as instrumental variables for obesity-related traits. We further performed multivariable MR to estimate the independent effect of BMI and WC on the risk of IPF.

Results: Increased BMI and WC were associated with higher risk of IPF [odds ratio (OR) = 1.51, 95% confidence interval (CI) (1.22–1.87), p = 1.27 × 10^–4, and OR = 1.71, 95% CI (1.08–2.72), p = 2.33 × 10^–2, respectively]. Similar results for the BMI and WC were obtained in the replicated analysis. Subsequently, only the result for BMI survived following the multiple testing correction and showed good consistency with the weighted median estimator. Sensitivity analyses indicated that there was no heterogeneity or horizontal pleiotropy for MR estimations. Further multivariable MR suggested that the BMI showed the same direction and similar magnitude with that in the univariable MR analysis. There was little evidence to support the causal role of WHR on the risk of IPF in this study.

Conclusion: Genetically determined BMI demonstrates a causal risk for IPF, which offers a novel insight into probing potential mechanisms. Meanwhile, these results also suggest that weight loss may be beneficial to IPF prevention.

Mortality and survival in idiopathic pulmonary fibrosis: a systematic review and meta-analysis

Background

: There are substantial advances in diagnosis and treatment for idiopathic pulmonary fibrosis (IPF), but without much evidence available on recent mortality and survival trends.

Methods

: A narrative synthesis approach was used to investigate the mortality trends, then meta-analyses for survival trends were carried out based on various time periods.

Results

: Six studies reported the mortality data for IPF in 22 countries, and 62 studies (covering 63 307 patients from 20 countries) reported survival data for IPF. Age-standardised mortality for IPF varied from approximately 0.5 to 12 per 100 000 population per year after year 2000. There were increased mortality trends for IPF in Australia, Brazil, Belgium, Canada, Czech Republic, Finland, France, Germany, Hungary, Italy, Lithuania, Netherlands, Poland, Portugal, Spain, Sweden, and UK, while Austria, Croatia, Denmark, Romania, and US showed decreased mortality trends. The overall 3-year and 5-year cumulative survival rates (CSRs) were 61.8% (95% CI, 58.7–64.9; I2=97.1%) and 45.6% (95% CI, 41.5–49.7; I2=97.7%), respectively. Prior to 2010, the pooled 3-year CSRs was 59.9% (95% CI, 55.8–64.1; I2>95.8%), then not significantly (p=0.067) increased to 66.2% (95% CI, 62.9–69.5; I2=92.6%) in the 2010s decade. After excluding three studies in which no patients received antifibrotics after year 2010, the pooled 3-year CSRs significantly (p=0.039) increased to 67.4% (95% CI, 63.9–70.9; I2=93.1%) in the 2010s decade.

Discussion

: IPF is a diagnosis associated with high mortality. There was no observed increasing survival trend for patients with IPF before year 2010, with then a switch to an improvement, which is probably multifactorial.

Connective-Tissue Growth Factor (CTGF/CCN2) Contributes to TGF-β1-Induced Lung Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease characterized by progressive and excessive accumulation of myofibroblasts and extracellular matrix in the lung. Connective-tissue growth factor (CTGF) exacerbates pulmonary fibrosis in radiation-induced lung fibrosis, and in this study, we demonstrate upregulation of CTGF in a rat lung fibrosis model induced by an adenovirus vector encoding active TGF-β1 (AdTGF-β1). We show that CTGF is also upregulated in patients with IPF. Expression of CTGF was upregulated in vascular smooth muscle cells cultured from fibrotic lungs on days 7 and 14 as well as endothelial cells sorted from fibrotic lungs on days 14 and 28. These findings suggest contributions of different cells in maintaining the fibrotic phenotype during fibrogenesis. Treatment of fibroblasts with recombinant CTGF along with TGF-β increases pro-fibrotic markers in fibroblasts, confirming the synergistic effect of recombinant CTGF with TGF-β in inducing pulmonary fibrosis. Also, fibrotic extracellular matrix upregulated CTGF expression, compared with normal extracellular matrix, suggesting that not only profibrotic mediators, but also a profibrotic environment contributes to fibrogenesis. We also showed that pamrevlumab, a CTGF inhibitory antibody, partially attenuates fibrosis in the model. These results suggest that pamrevlumab could be an option for treatment of pulmonary fibrosis.

[Epidemiology of fibrosing interstitial lung diseases in the department of Haute Garonne]

EPIDemio study is a multicenter, prospective and observational study. The objective is to estimate the prevalence and incidence of fibrosing interstitial lung diseases (ILDs) in the department of Haute Garonne (31) in France. Fifty-five pulmonologists from the Toulouse university hospital and 8 private establishments participated in this study. Two hundred and fifty-six cases of fibrosing ILDs were reported (gross overall prevalence: 22.8/100,000 and estimated 30.1/100,000. Idiopathic ILDs represent 55.8% of fibrosing ILDs ahead of systemic disease-related ILDs (24.6%) and ILDs associated with environmental exposure (13.3%). Idiopathic pulmonary fibrosis (IPF) represents 35.9% of fibrosing ILDs, which corresponds to a minimal prevalence of 8.2/100,000 and an estimated prevalence of 11.2/100,000. This study confirms epidemiological data collected in France and Europe.

Ageing mechanisms that contribute to tissue remodeling in lung disease

Age is a major risk factor for chronic respiratory diseases such as idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and certain phenotypes of asthma. The recent COVID-19 pandemic also highlights the increased susceptibility of the elderly to acute respiratory distress syndrome (ARDS), a diffuse inflammatory lung injury with often long-term effects (ie parenchymal fibrosis). Collectively, these lung conditions are characterized by a pathogenic reparative process that, rather than restoring organ function, contributes to structural and functional tissue decline. In the ageing lung, the homeostatic control of wound healing following challenge or injury has an increased likelihood of being perturbed, increasing susceptibility to disease. This loss of fidelity is a consequence of a diverse range of underlying ageing mechanisms including senescence, mitochondrial dysfunction, proteostatic stress and diminished autophagy that occur within the lung, as well as in other tissues, organs and systems of the body. These ageing pathways are highly interconnected, involving localized and systemic increases in inflammatory mediators and damage associated molecular patterns (DAMPs); along with corresponding changes in immune cell function, metabolism and composition of the pulmonary and gut microbiomes. Here we comprehensively review the roles of ageing mechanisms in the tissue remodeling of lung disease.

Sex Differences in the Incidence and Outcomes of Patients Hospitalized by Idiopathic Pulmonary Fibrosis (IPF) in Spain from 2016 to 2019

(1) Background: To assess sex differences in the incidence, characteristics, procedures and outcomes of patients admitted with idiopathic pulmonary fibrosis (IPF); and to analyze variables associated with in-hospital mortality (IHM). (2) Methods: We analyzed data collected by the Spanish National Hospital Discharge Database, 2016-2019. (3) Results: We identified 13,278 hospital discharges (66.4% men) of IPF (primary diagnosis 32.33%; secondary diagnosis: 67.67%). Regardless of the diagnosis position, IPF incidence was higher among men than women, increasing with age. Men had 2.74 times higher IPF incidence than women. Comorbidity was higher for men in either primary or secondary diagnosis. After matching, men had higher prevalence of pulmonary embolism and pneumonia, and women of congestive heart failure, dementia, rheumatoid disease and pulmonary hypertension. Invasive ventilation, bronchoscopy and lung transplantation were received more often by men than women. IHM was higher among men with IPF as primary diagnosis than among women and increased with age in both sexes and among those who suffered cancer, pneumonia or required mechanical ventilation. (4) Conclusions: Incidence of IPF was higher among men than women, as well as comorbidity and use of bronchoscopy, ventilation and lung transplantation. IHM was worse among men than women with IPF as primary diagnosis, increasing with age, cancer, pneumonia or mechanical ventilation use.

All-cause mortality of patients with idiopathic pulmonary fibrosis: a nationwide population-based cohort study in Korea

Most epidemiologic studies of patients with idiopathic pulmonary fibrosis (IPF) have been conducted in North America and Europe. Moreover, there are limited data concerning the cause of death and cause-specific mortality rate of IPF patients in population-based studies. We analyzed information from the Korean National Health Insurance Service database from 2006 to 2016. Patients with a diagnosis code of IPF were extracted from the database and we included those who satisfied the narrow definition of IPF diagnosis. Age- and sex-matched controls were randomly selected at a case-to-control rate of 1:3. We included 42,777 patients newly diagnosed with IPF during the study period. Their mean age was 64.6 years, and 65.4% were male. The age-standardized mortality rates were 85.66 (95% confidence interval [CI] 84.45–86.89) per 1000 person-years. The survival rates of IPF patients 1, 2, 3, 5, and 10 years after IPF diagnosis were 84.5%, 77.4%, 71.9%, 62.9%, and 48.4%, respectively. The standardized mortality ratio of IPF patients compared to that of the normal population was 4.66. The leading cause of death in IPF patients was respiratory causes, followed by cancer. Patients with IPF in Korea showed significantly higher mortality compared to the general population.

Global incidence and prevalence of idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive debilitating lung disease with considerable morbidity. Heterogeneity in epidemiologic studies means the full impact of the disease is unclear.

METHODS

A targeted literature search for population-based, observational studies reporting incidence and/or prevalence of IPF from January 2009 to April 2020 was conducted. Identified studies were aggregated by country. For countries with multiple publications, a weighted average was determined. Incidence and prevalence data were adjusted for between-study differences where possible. The final model included adjusted estimates of incidence and prevalence per 10,000 of the population with 95% confidence intervals. As prevalence estimates vary depending on the definitions used, estimates were based on a specific case definition of IPF.

RESULTS

Overall, 22 studies covering 12 countries met the inclusion criteria, with 15 reporting incidence and 18 reporting prevalence estimates. The adjusted incidence estimates (per 10,000 of the population) ranged from 0.35 to 1.30 in Asia-Pacific countries, 0.09 to 0.49 in Europe, and 0.75 to 0.93 in North America. Unadjusted and adjusted incidence estimates were consistent. The adjusted prevalence estimates ranged from 0.57 to 4.51 in Asia-Pacific countries, 0.33 to 2.51 in Europe, and 2.40 to 2.98 in North America. South Korea had the highest incidence and prevalence estimates. When prevalence estimates were compared to country-specific rare disease thresholds, IPF met the definition of a rare disease in all countries except South Korea. There were notable geographic gaps for IPF epidemiologic data.

CONCLUSIONS

Due to differences in study methodologies, there is worldwide variability in the reported incidence and prevalence of IPF. Based on the countries included in our analysis, we estimated the adjusted incidence and prevalence of IPF to be in the range of 0.09-1.30 and 0.33-4.51 per 10,000 persons, respectively. According to these prevalence estimates, IPF remains a rare disease. For consistency, future epidemiologic studies of IPF should take age, sex, smoking status, and the specificity of case definitions into consideration.

Comorbidities of Patients With Idiopathic Pulmonary Fibrosis in Four Latin American Countries. Are There Differences by Country and Altitude?

Background: Comorbidities in idiopathic pulmonary fibrosis (IPF) affect quality of life, symptoms, disease progression and survival. It is unknown what are the comorbidities in patients with IPF in Latin America (LA) and if there are differences between countries. Our objective was to compare IPF comorbidities in four countries and analyze possible differences by altitude. Methods: Patients with IPF according 2012 ATS/ERS/JRS/ALAT guidelines, from two cities with an altitude of ≥2,250 m: Mexico City (Mexico) and Bogotá (Colombia) and from three at sea level: Buenos Aires (Argentina) and Lima and Trujillo (Peru). Comorbidities and pulmonary function tests were taken from clinical records. Possible pulmonary hypertension (PH) was defined by findings in the transthoracic echocardiogram of systolic pulmonary arterial pressure (sPAP) >36 mmHg or indirect signs of PH in the absence of other causes of PH. Emphysema as the concomitant finding of IPF criteria on chest tomography plus emphysema in the upper lobes. ANOVA or Kruskal Wallis and χ²-tests were used for comparison. Results: Two hundred and seventy-six patients were included, 50 from Argentina, 86 from Colombia, 91 from Mexico and 49 from Peru. There prevalence of PH was higher in Colombia and Mexico (p < 0.001), systemic arterial hypertension in Argentina (p < 0.015), gastro-esophageal reflux and dyslipidemia in Colombia and Argentina (p < 0.001) and diabetes mellitus in Mexico (p < 0.007). Other comorbidities were obesity (28.4%), coronary artery disease (15.2%) and emphysema (14.9%), with no differences between countries. There was more PH in the altitude cities than those at sea level (51.7 vs. 15.3%, p < 0.001). In patients from Bogotá and Mexico City, arterial oxygen pressure, saturation (p < 0.001) and carbon monoxide diffusing capacity (p = 0.004) were significantly lower than in cities at sea level. Conclusions: In this study with a significant number of patients, we were able to describe and compare the comorbidities of IPF in four LA countries, which contributes to the epidemiological data of this disease in the region. The main results were the differences in comorbidities between the countries and more PH in the subjects residing in the cities of higher altitude, a finding that should be validated in future studies.

Morbidity and mortality reduction associated with polysomnography testing in idiopathic pulmonary fibrosis: a population-based cohort study

Background

It is not well-known if diagnosing and treating sleep breathing disorders among individuals with idiopathic pulmonary fibrosis (IPF) improves health outcomes. We evaluated the association between receipt of laboratory-based polysomnography (which is the first step in the diagnosis and treatment of sleep breathing disorders in Ontario, Canada) and respiratory-related hospitalization and all-cause mortality among individuals with IPF.

Methods

We used a retrospective, population-based, cohort study design, analyzing health administrative data from Ontario, Canada, from 2007 to 2019. Individuals with IPF were identified using an algorithm based on health administrative codes previously developed by IPF experts. Propensity score matching was used to account for potential differences in 41 relevant covariates between individuals that underwent polysomnography (exposed) and individuals that did not undergo polysomnography (controls), in order minimize potential confounding. Respiratory-related hospitalization and all-cause mortality were evaluated up to 12 months after the index date.

Results

Out of 5044 individuals with IPF identified, 201 (4.0%) received polysomnography, and 189 (94.0%) were matched to an equal number of controls. Compared to controls, exposed individuals had significantly reduced rates of respiratory-related hospitalization (hazard ratio [HR] 0.43, 95% confidence interval [CI] 0.24–0.75), p = 0.003) and all-cause mortality (HR 0.49, 95% CI 0.30–0.80), p = 0.004). Significantly reduced rate of respiratory-related hospitalization (but not all-cause mortality) was also observed among those with >  = 1 respiratory-related hospitalization (HR 0.38, 95% CI 0.15–0.99) and systemic corticosteroid receipt (HR 0.37, 95% CI 0.19–0.94) in the year prior to the index date, which reflect sicker subgroups of persons.

Conclusions

Undergoing polysomnography was associated with significantly improved clinically-important health outcomes among individuals with IPF, highlighting the potential importance of incorporating this testing in IPF disease management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01555-x.

Fibrotic extracellular matrix induces release of extracellular vesicles with pro-fibrotic miRNA from fibrocytes

RATIONALE

Extracellular vesicles (EVs) are small lipid vesicles, and EV-coupled microRNAs (miRNAs) are important modulators of biological processes. Fibrocytes are circulating bone marrow-derived cells that migrate into the injured lungs and contribute to fibrogenesis. The question of whether EV-coupled miRNAs derived from fibrocytes are able to regulate pulmonary fibrosis has not been addressed yet.

METHODS

Pulmonary fibrosis was induced in rats by intratracheal administration of an adenoviral gene vector encoding active transforming growth factor-β1 (TGF-β1) or control vector. Primary fibrocytes and fibroblasts were cultured from rat lungs and were sorted by anti-CD45 magnetic beads. Human circulating fibrocytes and fibrocytes in bronchoalveolar lavage fluid (BALF) were isolated by fibronectin-coated dishes. Fibrocytes were cultured on different stiffness plates or decellularised lung scaffolds. We also determined the effects of extracellular matrix (ECM) and recombinant TGF-β1 on the cellular and EV-coupled miRNA expression of fibrocytes.

RESULTS

The EVs of fibrocytes derived from fibrotic lungs significantly upregulated the expression of col1a1 of fibroblasts. Culturing on rigid plates or fibrotic decellularised lung scaffolds increased miR-21-5 p expression compared with soft plates or normal lung scaffolds. Dissolved ECM collected from fibrotic lungs and recombinant TGF-β1 increased miR-21-5 p expression on fibrocytes, and these effects were attenuated on soft plates. Fibrocytes from BALF collected from fibrotic interstitial pneumonia patients showed higher miR-21-5 p expression than those from other patients.

CONCLUSIONS

Our results indicate that ECM contributes to fibrogenesis through biomechanical and biochemical effects on miRNA expression in fibrocytes.

Human antigen R promotes lung fibroblast differentiation to myofibroblasts and increases extracellular matrix production

Idiopathic pulmonary fibrosis (IPF) is a disease of progressive scarring caused by excessive extracellular matrix (ECM) deposition and activation of α-SMA-expressing myofibroblasts. Human antigen R (HuR) is an RNA binding protein that promotes protein translation. Upon translocation from the nucleus to the cytoplasm, HuR functions to stabilize messenger RNA (mRNA) to increase protein levels. However, the role of HuR in promoting ECM production, myofibroblast differentiation, and lung fibrosis is unknown. Human lung fibroblasts (HLFs) treated with transforming growth factor β1 (TGF-β1) showed a significant increase in translocation of HuR from the nucleus to the cytoplasm. TGF-β-treated HLFs that were transfected with HuR small interfering RNA had a significant reduction in α-SMA protein as well as the ECM proteins COL1A1, COL3A, and FN1. HuR was also bound to mRNA for ACTA2, COL1A1, COL3A1, and FN. HuR knockdown affected the mRNA stability of ACTA2 but not that of the ECM genes COL1A1, COL3A1, or FN. In mouse models of pulmonary fibrosis, there was higher cytoplasmic HuR in lung structural cells compared to control mice. In human IPF lungs, there was also more cytoplasmic HuR. This study is the first to show that HuR in lung fibroblasts controls their differentiation to myofibroblasts and consequent ECM production. Further research on HuR could assist in establishing the basis for the development of new target therapy for fibrotic diseases, such as IPF.

IL-24 deficiency protects mice against bleomycin-induced pulmonary fibrosis by repressing IL-4-induced M2 program in macrophages

Idiopathic pulmonary fibrosis (IPF) is the most common type of idiopathic interstitial pneumonia and has one of the poorest prognosis. However, the molecular mechanisms underlying IPF progression remain largely unknown. In this study, we determined that IL-24, an IL-20 subfamily cytokine member, was increased both in the serum of IPF patients and the bronchoalveolar lavage fluid (BALF) of mice following bleomycin (BLM)-induced pulmonary fibrosis. As a result, IL-24 deficiency protected mice from BLM-induced lung injury and fibrosis. Specifically, loss of IL-24 significantly attenuated transforming growth factor β1 (TGF-β1) production and reduced M2 macrophage infiltration in the lung of BLM-induced mice. Mechanistically, IL-24 alone did not show a perceptible impact on the induction of M2 macrophages, but it synergized with IL-4 to promote M2 program in macrophages. IL-24 suppressed IL-4-induced expression of suppressor of cytokine signaling 1 (SOCS1) and SOCS3, through which it enhanced signal transducer and activator of transcription 6/peroxisome proliferator-activated receptor gamma (STAT6/PPARγ) signaling, thereby promoting IL-4-induced production of M2 macrophages. Collectively, our data support that IL-24 synergizes with IL-4 to promote macrophage M2 program contributing to the development of pulmonary fibrosis.

Snail-mediated partial epithelial mesenchymal transition augments the differentiation of local lung myofibroblast

The pathogenesis of pulmonary fibrosis diseases is considered to be related with environmental exposures, but the exact mechanism is unclear and there are no effective treatments. The contribution of epithelial-mesenchymal transition (EMT) to lung fibrosis has been controversial. It was found that partial EMT might play a vital role in renal fibrosis. We also found that partial EMT might be involved in fibrosis diseases. In this study, we used a silicosis animal model of pulmonary fibrosis to observe whether partial EMT existed in pulmonary fibrosis disease and a co-culture system culturing fibroblasts and alveolar epithelial cells stimulated by TGF-β1 to evaluate the probable effects of partial EMT, thus determined the probable role of partial EMT in pulmonary fibrosis diseases. In vivo, the results revealed that partial EMT might exist in silica-induced lung fibrosis model and Snail which is a potent EMT inducer was involved during the process. In vitro, a co-culture system was used to evaluate the effects of EMT in murine alveolar epithelial type II (ATII) cells on the activation of underlying murine lung fibroblasts into myofibroblasts. The results showed that epithelial cells undergoing EMT promoted the differentiation of lung myofibroblast and this epithelial-mesenchymal crosstalk was mainly controlled by Snail. Following Snail silencing the EMT and the activation of NIH-3T3 into myofibroblast were obviously inhibited. It indicated that targeting this novel Snail might be a viable strategy for the treatment of lung fibrosis diseases.

Proteomics in idiopathic pulmonary fibrosis: the quest for biomarkers

Idiopathic pulmonary fibrosis (IPF) is a debilitating chronic progressive and fibrosing lung disease that culminates in the destruction of alveolar integrity and dismal prognosis. Its etiology is unknown and pathophysiology remains unclear. While great advances have been made in elucidating the pathogenesis mechanism, considerable gaps related to information on pathogenetic pathways and key protein targets involved in the clinical course of the disease exist. These issues need to be addressed for better clinical management of this highly challenging disease. Omics approach has revolutionized the entire area of disease understanding and holds promise in its translation to clinical biomarker discovery. This review outlines the contribution of proteomics towards identification of important biomarkers in IPF in terms of their clinical utility, i.e. prognosis, differential diagnosis, disease progression and treatment monitoring. The major dysregulated pathways associated with IPF are also discussed. Based on numerous proteomics studies on human and animal models, it is proposed that IPF pathogenesis involves complex interactions of several pathways such as oxidative stress, endoplasmic reticulum stress, unfolded protein response, coagulation system, inflammation, abnormal wounding, fibroblast proliferation, fibrogenesis and deposition of extracellular matrix. These pathways and their key path-changing mediators need further validation in large well-planned multi-centric trials at various geographical locations for successful development of clinical biomarkers of this confounding disease.