Procoagulant signalling mechanisms in lung inflammation and fibrosis: novel opportunities for pharmacological intervention? Br J Pharmacol. 2008;153 Suppl 1:S367-S378. [PMID: 18223674 DOI: 10.1038/sj.bjp.0707603]

Anti-fibrotic effects of thrombin inhibition in systemic sclerosis-associated interstitial lung disease: Proof of concept

Introduction

Activation of the coagulation cascade leading to generation of thrombin is well documented in various forms of lung injury including systemic sclerosis-associated interstitial lung disease (SSc-ILD). We previously demonstrated that the direct thrombin inhibitor dabigatran inhibits thrombin-induced profibrotic signaling in lung fibroblasts isolated from scleroderma patients. The objective of this study was to characterize and compare lung fibroblasts from an SSc-ILD patient at baseline and after dabigatran treatment to ascertain this therapy's differential effects on fibrogenic gene expression.

Materials and methods

Lung fibroblasts isolated by bronchoalveolar lavage (BAL) from a SSc-ILD patient before and after receiving dabigatran (Pradaxa®) 75 mg twice daily for 6 months (ClinicalTrials.gov Identifier NCT02426229) were analyzed by RNA sequencing, real-time quantitative reverse transcription polymerase chain reaction (qRT)-PCR, and immunofluorescent staining.

Results

Thrombin inhibition for six-months by oral dabigatran resulted in significantly decreased expression of 708 lung fibroblast genes as compared to basal levels before dabigatran treatment. Using Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, we determined that thrombin-inhibition by dabigatran primarily affected extracellular matrix (ECM) and ECM-related genes. Fibrosis-associated genes, including smooth muscle alpha-actin (SMA, ACTA2), tenascin C, collagen 1 alpha 1 (COL1A1), collagen 3 alpha1 (COL3A1), collagen 8 alpha 2 (COL8A2), collagen 10 alpha 1 (COL10A1), collagen 5 alpha 1 (COL5A1), fibronectin 1, connective tissue growth factor (CTGF), and procollagen-lysine-2-oxoglutarate-5-dioxygenase-2 (PLOD2) were all significantly down regulated following thrombin inhibition by dabigatran treatment. Real-time qRT-PCR and immunofluorescent staining confirmed significant downregulation of the selected genes at the mRNA and protein levels.

Conclusion

Inhibition of thrombin in this SSc-ILD patient treated with low-dose dabigatran etexilate downregulated profibrotic proteins in lung fibroblasts, providing further support for the use of thrombin inhibitors as a therapeutic approach for the treatment of patients with SSc-ILD.

Cellular and Molecular Genetic Mechanisms of Lung Fibrosis Development and the Role of Vitamin D: A Review

Idiopathic pulmonary fibrosis remains a relevant problem of the healthcare system with an unfavorable prognosis for patients due to progressive fibrous remodeling of the pulmonary parenchyma. Starting with the damage of the epithelial lining of alveoli, pulmonary fibrosis is implemented through a cascade of complex mechanisms, the crucial of which is the TGF-β/SMAD-mediated pathway, involving various cell populations. Considering that a number of the available drugs (pirfenidone and nintedanib) have only limited effectiveness in slowing the progression of fibrosis, the search and justification of new approaches aimed at regulating the immune response, cellular aging processes, programmed cell death, and transdifferentiation of cell populations remains relevant. This literature review presents the key modern concepts concerning molecular genetics and cellular mechanisms of lung fibrosis development, based mainly on in vitro and in vivo studies in experimental models of bleomycin-induced pulmonary fibrosis, as well as the latest data on metabolic features, potential targets, and effects of vitamin D and its metabolites.

Therapeutic efficacy of thrombin-preconditioned mesenchymal stromal cell-derived extracellular vesicles on Escherichia coli-induced acute lung injury in mice

BACKGROUND

Acute lung injury (ALI) following pneumonia involves uncontrolled inflammation and tissue injury, leading to high mortality. We previously confirmed the significantly increased cargo content and extracellular vesicle (EV) production in thrombin-preconditioned human mesenchymal stromal cells (thMSCs) compared to those in naïve and other preconditioning methods. This study aimed to investigate the therapeutic efficacy of EVs derived from thMSCs in protecting against inflammation and tissue injury in an Escherichia coli (E. coli)-induced ALI mouse model.

METHODS

In vitro, RAW 264.7 cells were stimulated with 0.1 µg/mL liposaccharides (LPS) for 1 h, then were treated with either PBS (LPS Ctrl) or 5 × 107 particles of thMSC-EVs (LPS + thMSC-EVs) for 24 h. Cells and media were harvested for flow cytometry and ELISA. In vivo, ICR mice were anesthetized, intubated, administered 2 × 107 CFU/100 µl of E. coli. 50 min after, mice were then either administered 50 µL saline (ECS) or 1 × 109 particles/50 µL of thMSC-EVs (EME). Three days later, the therapeutic efficacy of thMSC-EVs was assessed using extracted lung tissue, bronchoalveolar lavage fluid (BALF), and in vivo computed tomography scans. One-way analysis of variance with post-hoc TUKEY test was used to compare the experimental groups statistically.

RESULTS

In vitro, IL-1β, CCL-2, and MMP-9 levels were significantly lower in the LPS + thMSC-EVs group than in the LPS Ctrl group. The percentages of M1 macrophages in the normal control, LPS Ctrl, and LPS + thMSC-EV groups were 12.5, 98.4, and 65.9%, respectively. In vivo, the EME group exhibited significantly lower histological scores for alveolar congestion, hemorrhage, wall thickening, and leukocyte infiltration than the ECS group. The wet-dry ratio for the lungs was significantly lower in the EME group than in the ECS group. The BALF levels of CCL2, TNF-a, and IL-6 were significantly lower in the EME group than in the ECS group. In vivo CT analysis revealed a significantly lower percentage of damaged lungs in the EME group than in the ECS group.

CONCLUSION

Intratracheal thMSC-EVs administration significantly reduced E. coli-induced inflammation and lung tissue damage. Overall, these results suggest therapeutically enhanced thMSC-EVs as a novel promising therapeutic option for ARDS/ALI.

PGC1-Alpha/Sirt3 Signaling Pathway Mediates the Anti-Pulmonary Fibrosis Effect of Hirudin by Inhibiting Fibroblast Senescence

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic lung disease for which there is a lack of effective pharmacological treatments. Hirudin, a natural peptide extracted from leeches, has been used for broad pharmacological purposes. In this study, we investigated the therapeutic effects of hirudin on IPF and its related mechanism of action. By constructing a mouse model of pulmonary fibrosis and treating it with hirudin in vivo, we found that hirudin exerted anti-fibrotic, anti-oxidative, and anti-fibroblast senescence effects. Moreover, using an in vitro model of stress-induced premature senescence in primary mouse lung fibroblasts and treating with hirudin, we observed inhibition of fibroblast senescence and upregulation of PGC1-alpha and Sirt3 expression. However, specific silencing of PGC1-alpha or Sirt3 suppressed the anti-fibroblast senescence effect of hirudin. Thus, the PGC1-alpha/Sirt3 pathway mediates the anti-fibroblast senescence effect of hirudin, potentially serving as a molecular mechanism underlying its anti-fibrosis and anti-oxidative stress effects exerted on the lungs.

Ercc1 DNA repair deficiency results in vascular aging characterized by VSMC phenotype switching, ECM remodeling, and an increased stress response

Cardiovascular diseases are the number one cause of death globally. The most important determinant of cardiovascular health is a person's age. Aging results in structural changes and functional decline of the cardiovascular system. DNA damage is an important contributor to the aging process, and mice with a DNA repair defect caused by Ercc1 deficiency display hypertension, vascular stiffening, and loss of vasomotor control. To determine the underlying cause, we compared important hallmarks of vascular aging in aortas of both Ercc1Δ/- and age-matched wildtype mice. Additionally, we investigated vascular aging in 104 week old wildtype mice. Ercc1Δ/- aortas displayed arterial thickening, a loss of cells, and a discontinuous endothelial layer. Aortas of 24 week old Ercc1Δ/- mice showed phenotypical switching of vascular smooth muscle cells (VSMCs), characterized by a decrease in contractile markers and a decrease in synthetic markers at the RNA level. As well as an increase in osteogenic markers, microcalcification, and an increase in markers for damage induced stress response. This suggests that Ercc1Δ/- VSMCs undergo a stress-induced contractile-to-osteogenic phenotype switch. Ercc1Δ/- aortas showed increased MMP activity, elastin fragmentation, and proteoglycan deposition, characteristic of vascular aging and indicative of age-related extracellular matrix remodeling. The 104 week old WT mice showed loss of cells, VSMC dedifferentiation, and senescence. In conclusion, Ercc1Δ/- aortas rapidly display many characteristics of vascular aging, and thus the Ercc1Δ/- mouse is an excellent model to evaluate drugs that prevent vascular aging in a short time span at the functional, histological, and cellular level.

A comprehensive comparison of the safety and efficacy of drugs in the treatment of idiopathic pulmonary fibrosis: a network meta-analysis based on randomized controlled trials

OBJECTIVE

Randomized controlled trials(RCTs) of multiple drugs for Idiopathic pulmonary fibrosis(IPF) have been reported and achieved a certain degree of efficacy, however, the difference in safety and efficacy of them for IPF is not yet well understood. The aim of this network meta-analysis is to assess their safety and efficacy in the treatment of IPF and differences in this safety and efficacy comprehensively.

METHODS

The PubMed, EMbase, CENTRAL and MEDLINE were retrieved to find out the RCTs of drugs in the treatment of IPF. The retrieval date is from construction to November 10, 2022. Stata 14.0 and RevMan 5.3 was used for statistical analysis.

REGISTRATION NUMBER

CRD42023385689.

RESULTS

Twenty-four studies with a total of 6208 patients were finally included, including RCTs of 13 drugs. The results of safety showed that there' s no difference in the incidence of SAEs of 13 drugs treated with IPF compared to placebo (P>0.05), and it's also found that Warfarin had a higher all-cause mortality for IPF than placebo (OR = 5.63, 95% CI [1.54 to 20.55]). SUCRA' s scatterplot showed that Pirfenidone, Nintedanib, Sildenafil and Imatinib were lower than placebo, and Warfarin, Ambrisentan and N-acetylcysteine were higher than placebo. The results of effectiveness showed that Nintedanib (MD = -0.08, 95% CI [-0.12 to -0.04]) improved FVC (L)absolute change from baseline in patients better than placebo, and Nintedanib (OR=1.81, 95% CI [1.23 to 2.66]), Pirfenidone (OR=1.85, 95%CI [1.26 to 2.71]) and Pamrevlumab (OR=4.11, 95% CI [1.25 to 13.58]) improved the proportion of patients with a decline in FVC ≥10% predicted better than placebo. SUCRA' s scatterplot showed that Pamrevlumab, Pirfenidone and Nintedanib were lower than placebo, and Warfarin and Ambrisentan were higher than placebo.

CONCLUSION

Compared with other drugs, Nintedanib and Pirfenidone can significantly slow the decline of lung function in patients with IPF, and the safety is higher. Therefore, they can be further promoted in clinical practice. Warfarin and Ambrisentan shouldn't be used clinically for IPF as the safety and efficacy of them are poor compared to other drugs and placebo. Pamrevlumab may become important drugs for the treatment of IPF in the future.

Pulmonary involvement from animal toxins: the cellular mechanisms

Venomous animals and their venom have always been of human interest because, despite species differences, coevolution has made them capable of targeting key physiological components of our bodies. Respiratory failure from lung injury is one of the serious consequences of envenomation, and the underlying mechanisms are rarely discussed. This review aims to demonstrate how toxins affect the pulmonary system through various biological pathways. Herein, we propose the common underlying cellular mechanisms of toxin-induced lung injury: interference with normal cell function and integrity, disruption of normal vascular function, and provocation of excessive inflammation. Viperid snakebites are the leading cause of envenomation-induced lung injury, followed by other terrestrial venomous animals such as scorpions, spiders, and centipedes. Marine species, particularly jellyfish, can also inflict such injury. Common pulmonary manifestations include pulmonary edema, pulmonary hemorrhage, and exudative infiltration. Severe envenomation can result in acute respiratory distress syndrome. Pulmonary involvement suggests severe envenomation, thus recognizing these mechanisms and manifestations can aid physicians in providing appropriate treatment.

Evaluation of Cisplatin-Induced Acute Renal Failure Amelioration Using Fondaparinux and Alteplase

Acute renal failure (ARF) is a deleterious condition with increased mortality or healthcare costs or dialysis-dependent end-stage renal disease. The study aims to compare prophylaxis with fondaparinux (Fund) vs. treatment with alteplase (Alt) in ameliorating cisplatin (Cis)-induced ARF. Sixty male mice were equally divided randomly into six groups of control, Cis, Alt, and Cis + Alt groups receiving normal saline for 10 days. All four groups except for the control received Cis (30 mg/kg, i.p.) on day 7, and 6 h later, both the Alt groups received Alt (0.9 mg/kg, i.v.). The animal groups Fund and Fund + Cis received Fund (5 mg/kg, i.p.) for 10 days, and the Fund + Cis group on day 7 received Cis. All the animal groups were euthanized 72 h after the Cis dose. The Fund + Cis group showed significantly increased expression levels of platelet count, retinoid X receptor alpha (RXR-α) and phosphorylated Akt (p-Akt) in addition to decreased levels of urea, blood urea nitrogen (BUN), uric acid, white blood cells (WBCs), red blood cells (RBCs), relative kidney body weight, kidney injury score, glucose, prothrombin (PT), A Disintegrin And Metalloproteinases-10 (ADAM10), extracellular matrix deposition, protease-activated receptor 2 (PAR-2), and fibrinogen expression when compared to the Cis-only group. Meanwhile, the Cis + Alt group showed increased caspase-3 expression in addition to decreased levels of urea, BUN, uric acid, WBCs, RBCs, glucose, platelet count and PT expression with a marked decrease in PAR-2 protein expression compared to the Cis group. The creatinine levels for both the Fund + Cis and Cis + Alt groups were found to be comparable to those of the Cis-only group. The results demonstrate that the coagulation system's activation through the stimulation of PAR-2 and fibrinogen due to Cis-induced ADAM10 protein expression mediated the apoptotic pathway, as indicated by caspase-3 expression through the p-Akt pathway. This is normally accompanied by the loss of RXR-α distal and proximal tubules as lipid droplets. When the animals were pre-treated with the anticoagulant, Fund, the previous deleterious effect was halted while the fibrinolytic agent, Alt, most of the time failed to treat Cis-induced toxicity.

Incidence and risk factors of venous thrombotic events in patients with interstitial lung disease during hospitalization

BACKGROUND

Studies on the incidence of venous thromboembolism (VTE) events in patients with interstitial lung disease (ILD) are limited and the results are inconsistent. The aim of this research was to investigate the incidence and risk factors of VTE in ILD during hospitalization.

MATERIALS AND METHODS

In this retrospective, cross-sectional, observational study, a total of 5009 patients diagnosed with ILD from January 2016 to March 2022 in our hospital were retrospectively included. In ILD patients, VTE including pulmonary thromboembolism (PTE) and deep vein thrombosis (DVT) were screened from the electronic medical record system. Diagnosis of PTE and DVT were performed by CT pulmonary angiography (CTPA), CTV or ultrasound. And then the incidence and risk factors of VTE in different types of ILD were assessed.

RESULTS

Among 5009 patients with ILD, VTE was detected in 129 (2.6%) patients, including 15(0.3%) patients with both PTE and DVT, 34 (0.7%) patients with PTE and 80 (1.6%) patients with DVT. 85.1% of patients with APE were in the intermediate-low risk group. The incidence of VTE in Anti-Neutrophil Cytoplasmic Antibodies -associated vasculitis related ILD (ANCA-AV-ILD), hypersensitivity pneumonitis and idiopathic pulmonary fibrosis (IPF) respectively was 7.9% and 3.6% and 3.5%. In patients with connective tissue disease-associated ILD (CTD-ILD), the incidence of VTE, DVT, PTE, combined PTE and DVT respectively was 3.0%, 2.3%, 0.4% and 0.3%. Among the various risk factors, different ILD categories, age ≥ 80 years (OR 4.178, 95% CI 2.097-8.321, P < 0.001), respiratory failure (OR 2.382, 95% CI 1.533-3.702, P < 0.001) and varicose veins (OR 3.718, 95% CI 1.066-12.964, P = 0.039) were independent risk factors of VTE. The incidence of VTE in patients with ILD increased with the length of time in hospital from 2.2% (< 7 days) to 6.4% (> 21 days).

CONCLUSION

The incidence of VTE during hospitalization in ILD patients was 2.6%, with a 1.6% incidence of DVT, higher than the 0.7% incidence of PTE. Advanced age, ILD categories, respiratory failure and varicose veins as independent risk factors for the development of VTE should be closely monitored.

Development of Adaptive Immunity and Its Role in Lung Remodeling

Asthma is characterized by airflow limitations resulting from bronchial closure, which can be either reversible or fixed due to changes in airway tissue composition and structure, also known as remodeling. Airway remodeling is defined as increased presence of mucins-producing epithelial cells, increased thickness of airway smooth muscle cells, angiogenesis, increased number and activation state of fibroblasts, and extracellular matrix (ECM) deposition. Airway inflammation is believed to be the main cause of the development of airway remodeling in asthma. In this chapter, we will review the development of the adaptive immune response and the impact of its mediators and cells on the elements defining airway remodeling in asthma.

Targeting Histone Deacetylases in Idiopathic Pulmonary Fibrosis: A Future Therapeutic Option

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease with limited therapeutic options, and there is a huge unmet need for new therapies. A growing body of evidence suggests that the histone deacetylase (HDAC) family of transcriptional corepressors has emerged as crucial mediators of IPF pathogenesis. HDACs deacetylate histones and result in chromatin condensation and epigenetic repression of gene transcription. HDACs also catalyse the deacetylation of many non-histone proteins, including transcription factors, thus also leading to changes in the transcriptome and cellular signalling. Increased HDAC expression is associated with cell proliferation, cell growth and anti-apoptosis and is, thus, a salient feature of many cancers. In IPF, induction and abnormal upregulation of Class I and Class II HDAC enzymes in myofibroblast foci, as well as aberrant bronchiolar epithelium, is an eminent observation, whereas type-II alveolar epithelial cells (AECII) of IPF lungs indicate a significant depletion of many HDACs. We thus suggest that the significant imbalance of HDAC activity in IPF lungs, with a "cancer-like" increase in fibroblastic and bronchial cells versus a lack in AECII, promotes and perpetuates fibrosis. This review focuses on the mechanisms by which Class I and Class II HDACs mediate fibrogenesis and on the mechanisms by which various HDAC inhibitors reverse the deregulated epigenetic responses in IPF, supporting HDAC inhibition as promising IPF therapy.

The innate immune response, microenvironment proteinases, and the COVID-19 pandemic: pathophysiologic mechanisms and emerging therapeutic targets

The coronavirus disease 2019 (COVID-19) pandemic, causing considerable mortality and morbidity worldwide, has fully engaged the biomedical community in attempts to elucidate the pathophysiology of COVID-19 and develop robust therapeutic strategies. To this end, the predominant research focus has been on the adaptive immune response to COVID-19 infections stimulated by mRNA and protein vaccines and on the duration and persistence of immune protection. In contrast, the role of the innate immune response to the viral challenge has been underrepresented. This overview focuses on the innate immune response to COVID-19 infection, with an emphasis on the roles of extracellular proteases in the tissue microenvironment. Proteinase-mediated signaling caused by enzymes in the extracellular microenvironment occurs upstream of the increased production of inflammatory cytokines that mediate COVID-19 pathology. These enzymes include the coagulation cascade, kinin-generating plasma kallikrein, and the complement system, as well as angiotensin-generating proteinases of the renin-angiotensin system. Furthermore, in the context of several articles in this Supplement elucidating and detailing the trajectory of diverse profibrotic pathways, we extrapolate these insights to explore how fibrosis and profibrotic pathways participate importantly in the pathogenesis of COVID-19. We propose that the lessons garnered from understanding the roles of microenvironment proteinases in triggering the innate immune response to COVID-19 pathology will identify potential therapeutic targets and inform approaches to the clinical management of COVID-19. Furthermore, the information may also provide a template for understanding the determinants of COVID-19-induced tissue fibrosis that may follow resolution of acute infection (so-called "long COVID"), which represents a major new challenge to our healthcare systems.

Incidence and Prognostic Impact of New-Onset Atrial Fibrillation in Patients with Severe Covid-19: A Retrospective Cohort Study

Background

Corona virus disease 2019 (COVID-19) contributes to cardiovascular complications including arrhythmias due to high inflammatory surge. Nevertheless, the common types of arrhythmia amongst severe COVID-19 is not well described. New onset atrial fibrillation(NOAF) is frequentlyseen in critically ill patients and therefore we aim to assess the incidence of NOAF in severe COVID -19and its association with prognosis.

Methods

This is a retrospective multicentre study including 109 consecutive patients admitted to intensive care units (ICU) with confirmed COVID-19 pneumonia and definitive outcome (death or discharge). The study period was between 11th March and 5th May 2020.

Results

Median age of our population was 59 years (IQR 53-65) and 83% were men. Nearly three-fourth of the population had two or more comorbidities. 14.6% developed NOAF during ICU stay with increased risk amongst older age and with underlying chronic heart failure and chronic kidney disease. NOAF developed earlier during the course of severe COVID-19 infection amongst non-survivors than those survived the illness andstrongly associated with increased in-hospital death (OR 5.4; 95% CI 1.7-17; p=0.004).

Conclusions

In our cohort with severe COVID-19, the incidence of new onset atrial fibrillation is comparatively lower than patients treated in ICU with severe sepsis in general. Presence of NOAF has shown to be a poor prognostic marker in this disease entity.

Chronic hypersensitivity pneumonitis is associated with an increased risk of venous thromboembolism: a retrospective cohort study

Background

Idiopathic pulmonary fibrosis (IPF) and chronic hypersensitivity pneumonitis share commonalities in pathogenesis shifting haemostasis balance towards the procoagulant and antifibrinolytic activity. Several studies have suggested an increased risk of venous thromboembolism in IPF. The association between venous thromboembolism and chronic hypersensitivity pneumonitis has not been studied yet.

Methods

A retrospective cohort study of IPF and chronic hypersensitivity pneumonitis patients diagnosed in single tertiary referral center between 2005 and 2018 was conducted. The incidence of symptomatic venous thromboembolism was evaluated. Risk factors for venous thromboembolism and survival among those with and without venous thromboembolism were assessed.

Results

A total of 411 (259 IPF and 152 chronic hypersensitivity) patients were included (mean age 66.7 ± 8.4 vs 51.0 ± 13.3 years, respectively). There were 12 (4.6%) incident cases of venous thromboembolism in IPF and 5 (3.3%) in chronic hypersensitivity pneumonitis cohort. The relative risk (RR) of venous thromboembolism in chronic hypersensitivity pneumonitis was not significantly different to that found in patients with IPF (7.1 vs 11.8/1000 person-years, RR 1.661 95% CI 0.545–6.019, respectively).

The treatment with systemic steroids (OR 5.38; 95% CI 1.65–18.8, p = 0.006) and GAP stage 3 (OR 7.85; 95% CI 1.49–34.9; p = 0.037) were significant risk factors for venous thromboembolism in IPF. Arterial hypertension and pulmonary hypertension significantly increased risk of venous thromboembolism in chronic hypersensitivity pneumonitis. There were no significant differences in survival between patients with and without venous thromboembolism.

Conclusions

The patients with chronic hypersensitivity pneumonitis have a marked increase in the risk of venous thromboembolism, similar to the patients with IPF. Venous thromboembolism does not affect the survival of patients with IPF and chronic hypersensitivity pneumonitis.

Protease-Activated Receptor-1 Antagonist Protects Against Lung Ischemia/Reperfusion Injury

Protease-activated receptor (PAR)-1 is a thrombin-activated receptor that plays an essential role in ischemia/reperfusion (IR)-induced acute inflammation. PAR-1 antagonists have been shown to alleviate injuries in various IR models. However, the effect of PAR-1 antagonists on IR-induced acute lung injury (ALI) has not yet been elucidated. This study aimed to investigate whether PAR-1 inhibition could attenuate lung IR injury. Lung IR was induced in an isolated perfused rat lung model. Male rats were treated with the specific PAR-1 antagonist SCH530348 (vorapaxar) or vehicle, followed by ischemia for 40 min and reperfusion for 60 min. To examine the role of PAR-1 and the mechanism of SCH530348 in lung IR injury, western blotting and immunohistochemical analysis of lung tissue were performed. In vitro, mouse lung epithelial cells (MLE-12) were treated with SCH530348 or vehicle and subjected to hypoxia-reoxygenation (HR). We found that SCH530348 decreased lung edema and neutrophil infiltration, attenuated thrombin production, reduced inflammatory factors, including cytokine-induced neutrophil chemoattractant-1, interleukin-6 and tumor necrosis factor-α, mitigated lung cell apoptosis, and downregulated the phosphoinositide 3-kinase (PI3K), nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in IR-injured lungs. In addition, SCH530348 prevented HR-induced NF-κB activation and inflammatory chemokine production in MLE12 cells. Our results demonstrate that SCH530348 exerts protective effects by blocking PAR-1 expression and modulating the downstream PI3K, NF-κB and MAPK pathways. These findings indicate that the PAR-1 antagonist protects against IR-induced ALI and is a potential therapeutic candidate for lung protection following IR injury.

Drug Repurposing Prediction and Validation From Clinical Big Data for the Effective Treatment of Interstitial Lung Disease

Interstitial lung diseases (ILDs) are a group of respiratory disorders characterized by chronic inflammation and fibrosis of the pulmonary interstitial tissues. Although the etiology of ILD remains unclear, some drug treatments are among the primary causes of ILD. In the present study, we analyzed the FDA Adverse Event Reporting System and JMDC Inc. insurance claims to identify a coexisting drug that reduced the incidence of ILD associated with the use of an anti-arrhythmic agent, amiodarone, and found that the thrombin inhibitor dabigatran prevented the amiodarone-induced ILD in both clinical datasets. In an experimental validation of the hypothesis, long-term oral treatment of mice with amiodarone caused a gradual decrease in body weight caused by respiratory insufficiency. In the lungs of amiodarone-treated mice, infiltration of macrophages was observed in parallel with a delayed upregulation of the platelet-derived growth factor receptor α gene. In contrast, co-treatment with dabigatran significantly attenuated these amiodarone-induced changes indicative of ILD. These results suggest that dabigatran is effective in preventing drug-induced ILD. This combinatorial approach of drug repurposing based on clinical big data will pave the way for finding a new treatment with high clinical predictability and a well-defined molecular mechanism.

Anticoagulant Use and Bleeding Risk in Central European Patients with Idiopathic Pulmonary Fibrosis (IPF) Treated with Antifibrotic Therapy: Real-World Data from EMPIRE

INTRODUCTION

Nintedanib, a tyrosine kinase receptor inhibitor, may be associated with increased bleeding risk. Thus, patients with an inherited predisposition to bleeding, or those receiving therapeutic doses of anticoagulants or high-dose antiplatelet therapy, have been excluded from clinical trials of nintedanib in idiopathic pulmonary fibrosis (IPF).

OBJECTIVE

Our objective was to examine real-world bleeding events in patients with IPF treated with antifibrotics, including those receiving anticoagulants and/or antiplatelet therapy.

METHODS

The European MultiPartner IPF Registry (EMPIRE) enrolled 2794 patients with IPF: group A (1828: no anticoagulant or antiplatelet treatment), group B (227: anticoagulant treatment), group C (659: antiplatelet treatment), and group D (80: anticoagulant and antiplatelet treatment). Overall, 673 (24.1%) received nintedanib and 933 (33.4%) received pirfenidone. Bleeding events and their relationship to antifibrotic and anticoagulation treatment were characterized.

RESULTS

Group A patients, versus those in groups B, C, and D, were typically younger and generally had the lowest comorbidity rates. A higher proportion of patients in groups A and C, versus group B, received nintedanib. Pirfenidone, most common in group D, was more evenly balanced across groups. In patients with reported bleeding events, seven of eight received nintedanib (groups A, C, and D). Bleeding incidence was 3.0, 0, 1.3, and 18.1 per 10,000 patient-years (groups A, B, C, and D, respectively).

CONCLUSION

Real-world data from EMPIRE showed that patients on anticoagulant medications received nintedanib less frequently, perhaps based on its mechanism of action. Overall, bleeding incidence was low (0.29%: nintedanib 0.25%; pirfenidone 0.04%) and irrespective of anticoagulant or antiplatelet therapy received (P = 0.072).

Risk of recurrent venous thromboembolism and bleeding in patients with interstitial lung disease: a cohort study

Interstitial lung disease (ILD) encompasses various parenchymal lung disorders, which has the potential to increase the risk of venous thromboembolism (VTE). To evaluate, in patients with ILD and VTE, the risk of recurrent VTE during follow-up after stopping anticoagulation. This was a cohort of patients with a first VTE recruited between 1997 and 2015. The primary outcome was adjudicated fatal or nonfatal recurrent VTE after stopping anticoagulation. Main secondary outcomes were major or clinically relevant non-major bleeding under anticoagulation. Among 4314 patients with VTE, 50 had ILD diagnosed before VTE. Of these, anticoagulation was stopped in 30 patients after a median duration of 180 days and continued indefinitely in 20 patients. During a median follow-up of 27.8 months after anticoagulation discontinuation, recurrent VTE occurred in 15 on 30 patients (annual incidence of 19.2 events per 100-person-years [95%CI 12.0-29.3], case-fatality rate of 6.7% [95%CI 1.21-29.8]). The risk of recurrence was threefold higher when VTE was unprovoked and case-fatality rate of recurrence was increased by 3 when VTE index was PE. During the anticoagulant period, (median duration of 8.6 months), 6 patients had a major or clinically relevant bleeding (annual incidence of 7.3 events per 100-person-years [95%CI 3.4-15.1], case-fatality rate of 16.7% [95%CI 3.0-56.4]). In patients with ILD, the risk of recurrent VTE after stopping anticoagulation and the risk of bleeding under anticoagulation were very high. Our results suggest that anticoagulation should not be prolonged beyond 3-6 months of anticoagulation in most of cases.

Echinochrome A Treatment Alleviates Fibrosis and Inflammation in Bleomycin-Induced Scleroderma

Scleroderma is an autoimmune disease caused by the abnormal regulation of extracellular matrix synthesis and is activated by non-regulated inflammatory cells and cytokines. Echinochrome A (EchA), a natural pigment isolated from sea urchins, has been demonstrated to have antioxidant activities and beneficial effects in various disease models. The present study demonstrates for the first time that EchA treatment alleviates bleomycin-induced scleroderma by normalizing dermal thickness and suppressing collagen deposition in vivo. EchA treatment reduces the number of activated myofibroblasts expressing α-SMA, vimentin, and phosphorylated Smad3 in bleomycin-induced scleroderma. In addition, it decreased the number of macrophages, including M1 and M2 types in the affected skin, suggesting the induction of an anti-inflammatory effect. Furthermore, EchA treatment markedly attenuated serum levels of inflammatory cytokines, such as tumor necrosis factor-α and interferon-γ, in a murine scleroderma model. Taken together, these results suggest that EchA is highly useful for the treatment of scleroderma, exerting anti-fibrosis and anti-inflammatory effects.

Antifibrotics in systemic sclerosis

Systemic sclerosis (SSc) is a rare and complex disease, involving multiple organs, with high morbidity and mortality. Fibrosis is the hallmark of SSc, although vascular and inflammatory mechanisms are also implicated in its pathogenesis. Disease management is challenging, due to its heterogeneous presentation, and to the limited number of controlled clinical trials to guide treating clinicians. Immunosuppressive agents have been used to prevent progression, especially in the lung, before irreversible injury occurs, with some, although modest, benefit. Nintedanib, a tyrosine kinase inhibitor, has recently demonstrated safety and efficacy in interstitial lung disease (ILD) associated with SSc, and many other antifibrotics are being assessed as possible beneficial therapies, with promising results. An important unmet need remains, to clarify to which patients, when, and with which agent therapy should be initiated, to achieve optimal outcomes. This review summarizes available evidence for current and emerging antifibrotic therapies in SSc patients.

Association Between Anticoagulation and Survival in Interstitial Lung Disease: An Analysis of the Pulmonary Fibrosis Foundation Patient Registry

BACKGROUND

Aberrations in the coagulation system have been implicated in the pathogenesis of interstitial lung disease (ILD). Anticoagulants have been proposed as a potential therapy in ILD; however, a randomized controlled trial examining warfarin as a treatment for IPF was terminated early due to increased death rates. This has led some to speculate that warfarin specifically may be harmful in ILD, and use of direct oral anticoagulants (DOACs) could result in superior outcomes.

RESEARCH QUESTION

The goal of this study was to delineate the relationship between anticoagulation and outcomes in patients with ILD through an analysis of the Pulmonary Fibrosis Foundation Patient Registry.

STUDY DESIGN AND METHODS

An analysis of all patients in the Pulmonary Fibrosis Foundation Patient Registry was performed. Patients were stratified into three groups: no anticoagulation, DOAC use, or warfarin use. Survival was analyzed by using both Kaplan-Meier curves and Cox proportional hazards models.

RESULTS

Of 1,911 patients included in the analysis, 174 (9.1%) were given anticoagulants; 93 (4.9%) received DOACs, and 81 (4.2%) received warfarin. There was a twofold increased risk of death or transplant for patients receiving DOACS; for warfarin, the risk was over two and half times greater. DOACs were not associated with an increased risk of mortality following adjustment for confounding variables. However, even after adjustment, patients given the anticoagulant warfarin remained at increased risk of mortality. In patients with IPF, warfarin was associated with reduced transplant-free survival, but DOACs were not. There was no statistically significant difference in survival between those receiving warfarin and those receiving a DOAC.

INTERPRETATION

The need for anticoagulation is associated with an increased risk for death or transplant in patients with ILD, in both the IPF and non-IPF population. Further research is required to determine if warfarin and DOACs present varying safety profiles in patients with ILD.

Anticoagulation Management in Severe Coronavirus Disease 2019 Patients on Extracorporeal Membrane Oxygenation

Objective

To explore special coagulation characteristics and anticoagulation management in extracorporeal membrane oxygenation (ECMO)–assisted patients with coronavirus disease 2019 (COVID-19).

Design

Single-center, retrospective observation of a series of patients.

Participants

Laboratory-confirmed severe COVID-19 patients who received venovenous ECMO support from January 20–May 20, 2020.

Interventions

This study analyzed the anticoagulation management and monitoring strategies, bleeding complications, and thrombotic events during ECMO support.

Measurements and Main Results

Eight of 667 confirmed COVID-19 patients received venovenous ECMO and had an elevated D-dimer level before and during ECMO support. An ECMO circuit pack (oxygenator and tubing) was replaced a total of 13 times in all 8 patients, and coagulation-related complications included oxygenator thrombosis (7/8), tracheal hemorrhage (5/8), oronasal hemorrhage (3/8), thoracic hemorrhage (3/8), bleeding at puncture sites (4/8), and cannulation site hemorrhage (2/8).

Conclusions

Hypercoagulability and secondary hyperfibrinolysis during ECMO support in COVID-19 patients are common and possibly increase the propensity for thrombotic events and failure of the oxygenator. Currently, there is not enough evidence to support a more aggressive anticoagulation strategy.

Combination Therapy With Polydeoxyribonucleotide and Pirfenidone Alleviates Symptoms of Acute Respiratory Distress Syndrome in Human Lung Epithelial A549 Cells

PURPOSE

Acute respiratory distress syndrome (ARDS) is characterized by its acute onset of symptoms such as bilateral pulmonary infiltrates, severe hypoxemia, and pulmonary edema. Many patients with ARDS survive in the acute phase, but then die from significant lung fibrosis.

METHODS

The effect of combination therapy with polydeoxyribonucleotide (PDRN) and pirfenidone on ARDS was investigated using human lung epithelial A549 cells. ARDS environment was induced by treatment with lipopolysaccharide and transforming growth factor (TGF)-β. Enzyme-linked immunoassay for connective tissue growth factor (CTGF) and hydroxyproline were conducted. Western blot for collagen type I, fibroblast growth factor (FGF), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 was performed.

RESULTS

In this study, 8-μg/mL PDRN enhanced cell viability. Combination therapy with PDRN and pirfenidone and pirfenidone monotherapy suppressed expressions of CTGF and hydroxyproline and inhibited expressions of collagen type I and FGF. Combination therapy with PDRN and pirfenidone and PDRN monotherapy suppressed expression of TNF-α and IL-1β.

CONCLUSION

The combination therapy with PDRN and pirfenidone exerted stronger therapeutic effect against lipopolysaccharide and TGF-β-induced ARDS environment compared to the PDRN monotherapy or pirfenidone monotherapy. The excellent therapeutic effect of combination therapy with PDRN and pirfenidone on ARDS was shown by promoting the rapid anti-inflammatory effect and inhibiting the fibrotic processes.

Identification and Modulation of Microenvironment Is Crucial for Effective Mesenchymal Stromal Cell Therapy in Acute Lung Injury

Rationale: There are controversial reports on applications of mesenchymal stromal cells (MSCs) in patients with acute respiratory distress syndrome (ARDS). Objectives: We hypothesized that lung microenvironment was the main determinant of beneficial versus detrimental effects of MSCs during ARDS. Methods: Lung proteome was profiled in three models of injury induced by acid instillation and/or mechanical ventilation in mice. Human gene of glutathione peroxidase-1 was delivered before MSC administration; or MSCs carrying human gene of IL-10 or hepatocyte growth factor were administered after lung injury. An inhibitory cocktail against IL-6, fibronectin, and oxidative stress was used in in vitro studies using human small airway epithelial cells and human MSCs after exposure to plasma of patients with ARDS. Measurements and Main Results: Distinct proteomic profiles were observed in three lung injury models. Administration of MSCs protected lung from ventilator-induced injury, whereas it worsened acid-primed lung injuries associated with fibrotic development in lung environment that had high levels of IL-6 and fibronectin along with low antioxidant capacity. Correction of microenvironment with glutathione peroxidase-1, or treatment with MSCs carrying human gene of IL-10 or hepatocyte growth factor after acid-primed injury, reversed the detrimental effects of native MSCs. Proteomic profiles obtained in the mouse models were also similarly observed in human ARDS. Treatment with the inhibitory cocktail in samples of patients with ARDS retained protective effects of MSCs in small airway epithelial cells. Conclusions: MSCs can be beneficial or detrimental depending on microenvironment at the time of administration. Identification of potential beneficiaries seems to be crucial to guide MSC therapy in ARDS.

Current and Emerging Drug Therapies for Connective Tissue Disease-Interstitial Lung Disease (CTD-ILD)

Interstitial lung disease (ILD) can be associated with all connective tissue diseases and is an important cause of morbidity and mortality. The management of connective tissue disease-interstitial lung disease (CTD-ILD) is challenging due substantial heterogeneity in disease behaviour and paucity of controlled clinical trials to guide treating clinicians. Not all patients require treatment, and the decision to treat needs to be individualised based on a patient's observed disease behaviour, baseline and longitudinal lung function measurements, extent of lung involvement on radiology and patient factors including age, co-morbidities and personal preference. If indicated, treatment of the CTD-ILD is largely with immunomodulation, with the aim to prevent progression of the ILD before further irreversible lung injury and disability occurs. Corticosteroids, cyclophosphamide, mycophenolate mofetil and azathioprine are the most common immunosuppressive agents currently used to treat CTD-ILD, demonstrating stability of lung function in case series and a small number of randomised controlled trials in ILD associated with systemic sclerosis. Biological and non-biological disease-modifying anti-rheumatic drugs, and the anti-fibrotics nintedanib and pirfenidone, have revolutionised the treatment of connective tissue diseases and idiopathic ILD, respectively. Furthermore, anti-fibrotics have recently demonstrated safety and efficacy in ILD associated with systemic sclerosis. There remains a critical unmet need to clarify when and in whom to initiate treatment, and which agent(s) to utilise to achieve optimal outcomes for CTD-ILD patients whilst minimising harms through prospective multicentre trials. This review highlights the challenges faced when treating patients with CTD-ILD and summarises available evidence for current, emerging and novel therapies.

Biomarker profiles of coagulopathy and alveolar epithelial injury in acute respiratory distress syndrome with idiopathic/immune-related disease or common direct risk factors

BACKGROUND

Altered coagulation and alveolar injury are the hallmarks of acute respiratory distress syndrome (ARDS). However, whether the biomarkers that reflect pathophysiology differ depending on the etiology of ARDS has not been examined. This study aimed to investigate the biomarker profiles of coagulopathy and alveolar epithelial injury in two subtypes of ARDS: patients with direct common risk factors (dARDS) and those with idiopathic or immune-related diseases (iARDS), which are classified as "ARDS without common risk factors" based on the Berlin definition.

METHODS

This retrospective, observational study included adult patients who were admitted to the intensive care unit (ICU) at a university hospital with a diagnosis of ARDS with no indirect risk factors. Plasma biomarkers (thrombin-antithrombin complex [TAT], plasminogen activator inhibitor [PAI]-1, protein C [PC] activity, procalcitonin [PCT], surfactant protein [SP]-D, and KL-6) were routinely measured during the first 5 days of the patient's ICU stay.

RESULTS

Among 138 eligible patients with ARDS, 51 were excluded based on the exclusion criteria (n = 41) or other causes of ARDS (n = 10). Of the remaining 87 patients, 56 were identified as having dARDS and 31 as having iARDS. Among the iARDS patients, TAT (marker of thrombin generation) and PAI-1 (marker of inhibited fibrinolysis) were increased, and PC activity was above normal. In contrast, PC activity was significantly decreased, and TAT or PAI-1 was present at much higher levels in dARDS compared with iARDS patients. Significant differences were also observed in PCT, SP-D, and KL-6 between patients with dARDS and iARDS. The receiver operating characteristic (ROC) analysis showed that areas under the ROC curve for PC activity, PAI-1, PCT, SP-D, and KL-6 were similarly high for distinguishing between dARDS and iARDS (PC 0.86, P = 0.33; PAI-1 0.89, P = 0.95; PCT 0.89, P = 0.66; and SP-D 0.88, P = 0.16 vs. KL-6 0.90, respectively).

CONCLUSIONS

Coagulopathy and alveolar epithelial injury were observed in both patients with dARDS and with iARDS. However, their biomarker profiles were significantly different between the two groups. The different patterns of PAI-1, PC activity, SP-D, and KL-6 may help in differentiating between these ARDS subtypes.

Therapeutic effects of the rhSOD2-Hirudin fusion protein on bleomycin-induced pulmonary fibrosis in mice

Idiopathic pulmonary fibrosis (IPF) is a disease with a poor prognosis and high mortality, posing a major threat to human health. Increased levels of inflammatory cytokines, reactive oxygen species and coagulation cascade have been extensively reported in IPF. We previously fused Hirudin and human manganese superoxide dismutase (hSOD2) to generate a dual-feature fusion protein, denoted as rhSOD2-Hirudin fusion protein. In this study, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and Hydroxyproline (HYP) assays were used to investigate the effects of rhSOD2-Hirudin protein on thrombin-induced fibroblast proliferation and collagen accumulation in vitro. Subsequently, the mice model of pulmonary fibrosis induced by bleomycin was used for evaluating the anti-inflammatory and anti-fibrotic effects of rhSOD2-Hirudin protein in vivo. Results showed that rhSOD2-Hirudin protein could inhibit the proliferation of fibroblasts and reduce the HYP production in vitro by inhibiting the activity of thrombin. In vivo experiments showed that lung inflammation and fibrosis were significantly decreased in rhSOD2-Hirudin protein-treated mice. Furthermore, rhSOD2-Hirudin protein treatment reduced profibrotic protein and gene expression while reducing the number of inflammatory cells in the lung. In conclusion, rhSOD2-Hirudin protein can effectively attenuate pulmonary fibrosis in vitro and in vivo, mainly by inhibiting the activity of thrombin meanwhile increasing SOD2 levels prevent cells from being damaged by reactive oxygen species, thereby mitigating IPF progression. This study provided important information on the feasibility and efficacy of rhSOD2-Hirudin protein as a novel therapeutic agent for IPF.

Management of Chronic Respiratory Failure in Interstitial Lung Diseases: Overview and Clinical Insights

Interstitial lung diseases (ILDs) may be complicated by chronic respiratory failure (CRF), especially in the advanced stages. Aim of this narrative review is to evaluate the current evidence in management of CRF in ILDs. Many physiological mechanisms underlie CRF in ILDs, including lung restriction, ventilation/perfusion mismatch, impaired diffusion capacity and pulmonary vascular damage. Intermittent exertional hypoxemia is often the initial sign of CRF, evolving, as ILD progresses, into continuous hypoxemia. In the majority of the cases, the development of CRF is secondary to the worsening of the underlying disease; however, associated comorbidities may also play a role. When managing CRF in ILDs, the need for pulmonary rehabilitation, the referral to lung transplant centers and palliative care should be assessed and, if necessary, promptly offered. Long-term oxygen therapy is commonly prescribed in case of resting or exertional hypoxemia with the purpose to decrease dyspnea and improve exercise tolerance. High-Flow Nasal Cannula oxygen therapy may be used as an alternative to conventional oxygen therapy for ILD patients with severe hypoxemia requiring both high flows and high oxygen concentrations. Non-Invasive Ventilation may be used in the chronic setting for palliation of end-stage ILD patients, although the evidence to support this application is very limited.

87-year-old woman with improved pulmonary function following accidental long-term inhalation therapy with dabigatran

Accidental long-term dabigatran etexilate inhalation was associated with subtherapeutic dabigatran serum concentrations in an elderly female patient with restrictive lung disease. A significant improvement in her pulmonary function was noted without other therapy directed towards her bronchopulmonary disease.

The M2a macrophage subset may be critically involved in the fibrogenesis of endometriosis in mice

RESEARCH QUESTION

Recent research has shown that endometriotic lesions are essentially wounds that undergo repeated tissue injury and repair, which results in epithelial-mesenchymal transition, fibroblast-to-myofibroblast transdifferentiation, smooth muscle metaplasia and ultimately fibrosis. Macrophages are a key regulator of tissue repair and fibrogenesis. But do macrophages also play a role in fibrogenesis of endometriosis, and, if yes, which subset of macrophages?

DESIGN

To elucidate the role of macrophages in fibrogenesis of endometriosis, we conducted three experiments in mice. In experiment 1, endometriotic tissue samples from female Balb/C mice with induced endometriosis were serially harvested to evaluate the role of macrophages in fibrogenesis. In experiments 2 and 3, female transgenic mice (C57BL/6J background) expressing the human diphtheria toxin receptor under the control of the CD11b promoter had macrophage depletion by diphtheria toxin injection after induction of endometriosis. Additionally, in experiment 3, adoptive transfer of different subsets of macrophage was carried out after macrophage depletion.

RESULTS

Lesional infiltration of M2 macrophages increased progressively as lesions progressed undisturbed, concomitant with progressive epithelial-mesenchymal transition, fibroblast-to-myofibroblast transdifferentiation and fibrosis. Macrophage depletion after induction of endometriosis significantly reduced lesional infiltration of total macrophages, significantly reduced lesional infiltration of M2 macrophages and significantly reduced lesional fibrotic content and lesion weight (P < 0.05). Finally, adoptive transfer of M2a, but not M1 or M2c macrophages, systemically after macrophage depletion significantly increased the extent of fibrosis in lesions (P = 1.6 × 10^-10).

CONCLUSIONS

The identification of a particular macrophage subset in fibrogenesis of endometriosis should further help to shed new light on the pathophysiology of endometriosis.

Signaling Crosstalk of TGF-β/ALK5 and PAR2/PAR1: A Complex Regulatory Network Controlling Fibrosis and Cancer

Both signaling by transforming growth factor-β (TGF-β) and agonists of the G Protein-coupled receptors proteinase-activated receptor-1 (PAR1) and -2 (PAR2) have been linked to tissue fibrosis and cancer. Intriguingly, TGF-β and PAR signaling either converge on the regulation of certain matrix genes overexpressed in these pathologies or display mutual regulation of their signaling components, which is mediated in part through sphingosine kinases and sphingosine-1-phosphate and indicative of an intimate signaling crosstalk between the two pathways. In the first part of this review, we summarize the various regulatory interactions that have been discovered so far according to the organ/tissue in which they were described. In the second part, we highlight the types of signaling crosstalk between TGF-β on the one hand and PAR2/PAR1 on the other hand. Both ligand–receptor systems interact at various levels and by several mechanisms including mutual regulation of ligand–ligand, ligand–receptor, and receptor–receptor at the transcriptional, post-transcriptional, and receptor transactivation levels. These mutual interactions between PAR2/PAR1 and TGF-β signaling components eventually result in feed-forward loops/vicious cycles of matrix deposition and malignant traits that exacerbate fibrosis and oncogenesis, respectively. Given the crucial role of PAR2 and PAR1 in controlling TGF-β receptor activation, signaling, TGF-β synthesis and bioactivation, combining PAR inhibitors with TGF-β blocking agents may turn out to be more efficient than targeting TGF-β alone in alleviating unwanted TGF-β-dependent responses but retaining the beneficial ones.

Roles of high-mobility group box 1 and thrombin in murine pulmonary fibrosis and the therapeutic potential of thrombomodulin

Cross talk between inflammation and coagulation plays important roles in acute or subacute progressive pulmonary fibrosis characterized by diffuse alveolar damage. Thrombomodulin is a physiological inhibitor of high-mobility group box 1 (HMGB1), and thrombin and may be effective for this condition. This study investigated the roles of HMGB1 and thrombin in the pathophysiology of bleomycin-induced pulmonary fibrosis and the efficacy of recombinant human soluble thrombomodulin (rhTM). Pulmonary fibrosis was induced in wild-type C57BL/6 mice by intratracheal instillation of bleomycin. We first assessed HMGB1, thrombin, transforming growth factor (TGF)-β1, and α-smooth muscle actin (SMA) levels in bronchoalveolar lavage fluid and lung tissue sections over time. Expression of HMGB1 and thrombin was elevated before that of TGF-β1 and α-SMA and remained high during the fibrotic phase after bleomycin instillation. We next examined whether in vitro stimulation with HMGB1 and thrombin induced expression of TGF-β1 and α-SMA in cultured alveolar macrophages and lung fibroblasts, respectively, by performing quantitative PCR, enzyme-linked immunosorbent assay, Western blot, and immunofluorescence analyses. HMGB1 and thrombin stimulation induced TGF-β1 production by alveolar macrophages, and thrombin stimulation also induced α-SMA expression in lung fibroblasts. Finally, we evaluated the effect of rhTM on bleomycin-induced pulmonary fibrosis. Compared with the vehicle control, both early and late-phase administration of rhTM suppressed the fibrotic process. Our results suggest that HMGB1 and thrombin were involved in the pathophysiology of pulmonary fibrosis via production of profibrotic proteins and that rhTM attenuated bleomycin-induced pulmonary fibrosis. rhTM may be a therapeutic option for acute or subacute pulmonary fibrosis.

Metalloproteinase-9 contributes to endothelial dysfunction in atherosclerosis via protease activated receptor-1

The atherosclerotic process begins when vascular endothelial cells undergo pro-inflammatory changes such as aberrant activation to dysfunctional phenotypes and apoptosis, leading to loss of vascular integrity. Our laboratory has demonstrated that exposure of mice to second hand smoke triggers an increase in expression of metalloproteinase-9. Further, metalloproteinase-9 released by second hand smoke-activated leukocytes may propagate pro-atherogenic alterations in endothelial cells. We have shown that levels of metalloproteinase-9 were increased in the plasma from apolipoprotein E deficient (ApoE-/-) mice exposed to second hand smoke relative to non-exposed controls. Moreover, we have collected data from two different, but complementary, treatments of second hand smoke exposed atherosclerotic mice. Animals received either cell specific metalloproteinase-9 directed siRNA to minimize metalloproteinase-9 expression in neutrophils and endothelial cells, or a pharmacological inhibitor of Bruton's tyrosine kinase which indirectly limits metalloproteinase-9 production in neutrophils. These treatments reduced atherosclerotic changes in mice and improved overall vascular health. We also demonstrated that metalloproteinase-9 could activate endothelial cells and induce their apoptosis via cleavage of protease activated receptor-1. In summary, better understanding of metalloproteinase-9's pathogenic capabilities as well as novel signaling pathways involved may lead to development of treatments which may provide additional benefits to atherosclerosis patients with a history of second hand smoke exposure.

Comorbidities in interstitial lung diseases

Fibrosing lung disorders include a large number of diseases with diverse behaviour. Patients can die because of the progression of their illness, remain stable or even improve after appropriate treatment has been instituted. Comorbidities, such as acute and chronic infection, gastro-oesophageal reflux, pulmonary hypertension, lung cancer, cardiovascular diseases, and obstructive sleep apnoea, can pre-exist or develop at any time during the course of the disease and, if unidentified and untreated, may impair quality of life, impact upon the respiratory status of the patients, and ultimately lead to disease progression and death. Therefore, early identification and accurate treatment of comorbidities is essential.

Risk of Pulmonary Embolism and Deep Venous Thrombosis in Systemic Sclerosis: A General Population-Based Study

OBJECTIVE

To determine the risk of venous thromboembolism (VTE) (pulmonary embolism [PE] and deep vein thrombosis [DVT]) in individuals with incident systemic sclerosis (SSc; scleroderma) in the general population.

METHODS

Using a population database that includes all residents of British Columbia, Canada, we conducted a cohort study of all patients with incident SSc and up to 10 age-, sex-, and entry time-matched individuals from the general population. We compared incidence rates of PE, DVT, and VTE between the 2 groups according to SSc disease duration. We calculated hazard ratios (HRs), adjusting for confounders.

RESULTS

Among 1,245 individuals with SSc (83% female, mean age 56 years), the incidence rates of PE, DVT, and VTE were 3.47, 3.48, and 6.56 per 1,000 person-years, respectively, whereas the corresponding rates were 0.78, 0.76, and 1.37 per 1,000 person-years among 12,670 non-SSc individuals. Compared with non-SSc individuals, the multivariable HRs among SSc patients were 3.73 (95% confidence interval [95% CI] 1.98-7.04), 2.96 (95% CI 1.54-5.69), and 3.47 (95% CI 2.14-5.64) for PE, DVT, and VTE, respectively. The age-, sex-, and entry time-matched HRs for PE, DVT, and VTE were highest during the first year after SSc diagnosis (32.77 [95% CI 6.60-162.75], 8.50 [95% CI 3.13-23.04], and 12.03 [95% CI 5.27-27.45], respectively).

CONCLUSION

These findings provide population-based evidence that SSc patients are at a substantially increased risk of VTE, especially within the first year after SSc diagnosis. Increased monitoring for this potentially fatal outcome and its modifiable risk factors is warranted in this patient population.

Asthma is associated with enhanced thrombin formation and impaired fibrinolysis

BACKGROUND

There is evidence that altered blood coagulation and fibrinolysis are involved in the pathogenesis of asthma. Increased thromboembolic risk has been reported in asthmatics.

OBJECTIVE

To investigate whether enhanced thrombin generation and impaired fibrinolysis occur in asthmatics.

METHODS

Plasma thrombin generation profile together with a computational assessment of thrombin dynamics and fibrinolytic capacity expressed as clot lysis time (CLT) were determined in 164 consecutive patients with stable asthma and 72 controls matched for age, gender, weight and smoking.

RESULTS

Asthma patients had 20.2% increased endogenous thrombin potential (ETP), 41.4% higher peak thrombin concentration, 61% higher maximal prothrombin conversion rate, 15.5% faster rate of thrombin formation (all, P < 0.0001) and 10% lower thrombin decay capacity (P = 0.0004) compared with controls. Asthmatics had also 14.4% longer CLT (P = 0.001) associated with 21.3% higher plasminogen activator inhibitor-1 (PAI-1) (P < 0.0001), and 13% higher plasma α2 -macroglobulin (P = 0.0002). Using ETP and CLT above 75th percentile of the control values as the cut-off levels, we found increased risks of enhanced thrombin generation and hypofibrinolysis in asthmatics, also after correction for potential confounders. ETP and CLT were associated inversely with forced expiratory volume in 1 s/vital capacity (FEV1 /VC) index, after adjustment for age and body mass index. Non-allergic asthma (n = 70, 42.6%) was characterized by 17.5% longer CLT (P = 0.02), which positively associated with PAI-1. Thrombin generation profile was not affected by allergy.

CONCLUSION AND CLINICAL RELEVANCE

Asthma is associated with enhanced thrombin generation and impaired fibrinolysis, which might contribute to thromboembolic events in this disease.

Unfavourable effects of medically indicated oral anticoagulants on survival in idiopathic pulmonary fibrosis

Procoagulant and antifibrinolytic activity has been associated with idiopathic pulmonary fibrosis (IPF); however, investigation of anticoagulant therapy in IPF has suggested deleterious effects. This post hoc analysis evaluated the effect of medically indicated anticoagulation on mortality and other clinical outcomes in IPF.Patients randomised to placebo (n=624) from three controlled trials in IPF were analysed by oral anticoagulant use. End-points included all-cause and IPF-related mortality, disease progression, hospitalisation, and adverse events, over 1 year.At baseline, 32 (5.1%) patients randomised to placebo were prescribed anticoagulants for non-IPF indications, 29 (90.6%) of whom received warfarin. Unadjusted analyses demonstrated significantly higher all-cause and IPF-related mortality at 1 year in baseline anticoagulant users versus nonusers (15.6% versus 6.3%, p=0.039 and 15.6% versus 3.9%, p=0.002, respectively). In multivariate analyses, baseline use of anticoagulants was an independent predictor of IPF-related mortality (hazard ratio 4.7, p=0.034), but not other end-points. Rates of bleeding and cardiac events did not differ significantly between groups. In an exploratory analysis, anticoagulant use at any time during the study was an independent predictor of all end-points.This post hoc analysis suggests that anticoagulants used for non-IPF indications may have unfavourable effects in IPF patients. Future studies are needed to explore this relationship further.

Stanniocalcin-1 inhibits thrombin-induced signaling and protects from bleomycin-induced lung injury

Thrombin-induced and proteinase-activated receptor 1 (PAR1)-mediated signaling increases ROS production, activates ERK, and promotes inflammation and fibroblast proliferation in bleomycin-induced lung injury. Stanniocalcin-1 (STC1) activates anti-oxidant pathways, inhibits inflammation and provides cytoprotection; hence, we hypothesized that STC1 will inhibit thrombin/PAR1 signaling and protect from bleomycin-induced pneumonitis. We determined thrombin level and activity, thrombin-induced PAR-1-mediated signaling, superoxide generation and lung pathology after intra-tracheal administration of bleomycin to WT and STC1 Tg mice. Lungs of bleomycin-treated WT mice display: severe pneumonitis; increased generation of superoxide; vascular leak; increased thrombin protein abundance and activity; activation of ERK; greater cytokine/chemokine release and infiltration with T-cells and macrophages. Lungs of STC1 Tg mice displayed none of the above changes. Mechanistic analysis in cultured pulmonary epithelial cells (A549) suggests that STC1 inhibits thrombin-induced and PAR1-mediated ERK activation through suppression of superoxide. In conclusion, STC1 blunts bleomycin-induced rise in thrombin protein and activity, diminishes thrombin-induced signaling through PAR1 to ERK, and inhibits bleomycin-induced pneumonitis. Moreover, our study identifies a new set of cytokines/chemokines, which play a role in the pathogenesis of bleomycin-induced lung injury. These findings broaden the array of potential therapeutic targets for the treatment of lung diseases characterized by thrombin activation, oxidant stress and inflammation.

Airway factor XIII associates with type 2 inflammation and airway obstruction in asthmatic patients

BACKGROUND

Coagulation Factor XIII (FXIII) plays an important role in wound healing by stabilizing fibrin clots and cross-linking extracellular matrix proteins. FXIII is expressed in cells of the monocyte/macrophage and dendritic cell lineages in response to type 2 cytokines.

OBJECTIVE

We sought to determine the association between FXIII and asthma pathobiology.

METHODS

We analyzed the expression of FXIII mRNA and protein levels in bronchoalveolar lavage samples obtained before and after segmental allergen challenge from patients with mild asthma and in induced sputum samples collected from patients with mild-to-moderate and severe asthma.

RESULTS

FXIII mRNA and protein levels were highly upregulated in bronchoalveolar cells and fluid after allergen challenge and mRNA levels correlated with protein levels. In sputum of asthmatic patients, FXIII expression was positively correlated with type 2 immune response and dendritic cell markers (CD209 and CD207). FXIII expression was also associated with increased airflow limitation (FEV1/forced vital capacity and residual volume/total lung capacity ratios) and greater reversibility to β-agonists.

CONCLUSIONS

FXIII expression was upregulated in the airways of asthmatic patients after allergen exposure. Expression in the sputum of asthmatic patients correlated with the type 2 immune response and airflow limitation. Excessive activity of FXIII could contribute to the pathophysiology of airway obstruction in asthmatic patients.

The simultaneous occurrence of both hypercoagulability and hypofibrinolysis in blood and serum during systemic inflammation, and the roles of iron and fibrin(ogen)

Although the two phenomena are usually studied separately, we summarise a considerable body of literature to the effect that a great many diseases involve (or are accompanied by) both an increased tendency for blood to clot (hypercoagulability) and the resistance of the clots so formed (hypofibrinolysis) to the typical, 'healthy' or physiological lysis. We concentrate here on the terminal stages of fibrin formation from fibrinogen, as catalysed by thrombin. Hypercoagulability goes hand in hand with inflammation, and is strongly influenced by the fibrinogen concentration (and vice versa); this can be mediated via interleukin-6. Poorly liganded iron is a significant feature of inflammatory diseases, and hypofibrinolysis may change as a result of changes in the structure and morphology of the clot, which may be mimicked in vitro, and may be caused in vivo, by the presence of unliganded iron interacting with fibrin(ogen) during clot formation. Many of these phenomena are probably caused by electrostatic changes in the iron-fibrinogen system, though hydroxyl radical (OH˙) formation can also contribute under both acute and (more especially) chronic conditions. Many substances are known to affect the nature of fibrin polymerised from fibrinogen, such that this might be seen as a kind of bellwether for human or plasma health. Overall, our analysis demonstrates the commonalities underpinning a variety of pathologies as seen in both hypercoagulability and hypofibrinolysis, and offers opportunities for both diagnostics and therapies.

Permanent alveolar collapse is the predominant mechanism in idiopathic pulmonary fibrosis

Alveolar epithelial cell loss and impaired epithelial cell regeneration are currently accepted as central initiating events in idiopathic pulmonary fibrosis (IPF), but subsequent downstream effects remain uncertain. The most accepted downstream effect is aberrant and dysregulated mesenchymal cell proliferation and excess extracellular matrix (ECM) accumulation. However, biochemical and imaging studies have perhaps somewhat surprisingly indicated little increase in total lung collagen and lung tissue, and have rather shown a substantial decrease in lung aeration and lung air volume. Loss of tissue aeration is a consequence of alveolar collapse, which occurs in IPF as a result of apposition and septal incorporation of denuded basal lamina. Permanent alveolar collapse is well-documented following epithelial injury, has the ability to mimic interstitial fibrosis radiologically and histologically, and is a better supported explanation than dysregulated fibroblast proliferation and excess ECM accumulation for the constellation of findings in patients with IPF.

Pharmacologic therapies for idiopathic pulmonary fibrosis, past and future

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

Promising new treatment targets in patients with fibrosing lung disorders

The processes of lung fibrogenesis and fibrotic healing are common to a number of conditions with different etiologies. The lungs are the only affected organ in some cases, whereas in others, several organ systems are involved. Therapeutic options can be discussed from various perspectives. In this review, we address the localization of therapeutic targets with regard to cell compartments, including secreted ligands, cell surface, plasma membrane-cytosol interplay, cytosol and nucleus. Complex approach using stem cell therapy is also discussed. As the prognosis of patients with these disorders remains grim, treatment combinations targeting different molecules within the cell should sometimes be considered. It is reasonable to assume that blocking specific pathways will more likely lead to disease stabilization, while stem cell-based treatments could potentially restore lung architecture. Gene therapy could be a candidate for preventive care in families with proven specific gene polymorphisms and documented familial lung fibrosis. Chronobiology, that takes into account effect of circadian rhythm on cell biology, has demonstrated that timed drug administration can improve treatment outcomes. However, the specific recommendations for optimal approaches are still under debate. A multifaceted approach to interstitial lung disorders, including cooperation between those doing basic research and clinical doctors as well as tailoring research and treatment strategies toward (until now) unmet medical needs, could improve our understanding of the diseases and, above all, provide benefits for our patients.