Preventive effect of irbesartan on bleomycin-induced lung injury in mice

Time course of histopathology of bleomycin-induced pulmonary fibrosis using an intratracheal sprayer in mice

Idiopathic pulmonary fibrosis (IPF) is a poor prognosis disease that affects approximately 5 million people worldwide, and the detailed mechanisms underlying the pathogenesis of IPF remain unclear. Bleomycin-induced pulmonary fibrosis has been widely used as a representative animal model of IPF that induces fibrosis in lung tissue. The lungs of rodent consist of five lobes and each bronchus enters each lobe of the lung at a different bifurcation angle, path length, and diameter. The method of administration of bleomycin is considered as important thing to establish appropriate animal models. We conducted a time-dependent histopathological study to examine how pulmonary fibrosis develops in each lung lobe when bleomycin was intratracheally sprayed in ICR mice. And we then explored the suitable points for evaluation of anti-fibrotic agents in this model. As a result, we found that homogeneous fibrosis was induced in the 5 lobes of the lungs following initial inflammation. The expression of transforming growth factor (TGF)-β1 and phospho-Smad2 (pSmad2) was observed from Day 1, and their positivity increased until Day 21. In conclusion, we have observed a detailed time course of histological changes in bleomycin-induced pulmonary fibrosis in ICR mice using the aerosolization technique. We found that our protocol can induce a highly homogeneous lesion in the lung and that the most suitable time point to assess anti-fibrotic agents is 14 days after treatment in this model.

Irbesartan eases lipopolysaccharide-induced lung injury In Vitro and In Vivo

Acute lung injury (ALI) is classified as a devastating pulmonary disorder contributing to significant incidence and fatality rate. Irbesartan (IRB) is an angiotensin II receptor blocker that has been proposed to protect against oleic acid-induced ALI. To this end, the current study is concentrated on ascertaining the role of IRB in ALI and figuring out the probable action mechanism. First, cell counting kit-8 (CCK-8) appraised the viability of human pulmonary microvascular endothelial cells (HPMVECs) exposed to ascending concentrations of IRB. HPMVEC injury model and a mouse model of ALI induced by lipopolysaccharide (LPS) were pretreated by IRB. In vitro, cell viability was estimated by CCK-8 assay, and lactate dehydrogenase (LDH) release was tested by LDH assay kit. Enzyme-linked immunosorbent assay (ELISA) and Western blotting estimated the expression levels of inflammatory factors. Fluorescein isothiocyanate-dextran was used to assess HPMVEC permeability. Western blotting examined the expression of adherent and tight junction proteins. In vivo, hematoxylin and eosin staining evaluated lung tissue damage and lung wet/dry (W/D) weight was measured. ELISA analyzed the levels of inflammatory factors in the serum and bronchoalveolar lavage fluid (BALF), and Western blotting examined the expression of inflammatory factors. The total cell, neutrophil, and macrophage numbers in BALF were determined using a cell counter. Lung capillary permeability was assayed by Evans blue albumin and total protein concentration in BALF was measured using bicinchoninic acid method. Immunofluorescence assay and Western blotting examined the expression of adherent and tight junction proteins in lung tissues. It was observed that IRB dose-dependently enhanced the viability while reduced LDH release, inflammatory response as well as permeability in LPS-challenged HPMVECs in vitro. In addition, LPS-stimulated lung tissue damage, pulmonary edema, inflammatory response as well as lung capillary permeability in vivo were all reversed following IRB treatment. Collectively, IRB treatment might elicit protective behaviors against LPS-triggered ALI.

Geranylgeranylacetone, an inducer of heat shock protein 70, attenuates pulmonary fibrosis via inhibiting NF-κB/NOX4/ROS signalling pathway in vitro and in vivo

Idiopathic pulmonary fibrosis (IPF) is a devastating and progressive pulmonary disease which is characterized by epithelial cell damage and extracellular collagen deposition. To date, the therapeutic options for IPF are still very limited, so the relevant mechanisms need to be explored. Heat shock protein 70 (HSP70), which has protective versus antitumor effects on cells under stress, is a member of the heat shock protein family. In the current study, qRT-PCR, western blotting, immunofluorescence staining, and migration assays were used to explore the Epithelial-mesenchymal transition (EMT) process in BEAS-2B cells. Moreover, the role of GGA in the process of pulmonary fibrosis was detected by HE, Masson staining, pulmonary function test and immunohistochemistry in C57BL/6 mice. Our results indicated that GGA, as an inducer of HSP70, enhanced the transformation of BEAS-2B cells from epithelial to mesenchymal cells through the NF-κB/NOX4/ROS (reactive oxygen species) signalling pathway and could significantly reduce apoptosis of BEAS-2B cells induced by TGF-β1(Transforming growth factor β1) in vitro. In vivo studies demonstrated that HSP70-inducing drugs, such as GGA, attenuated pulmonary fibrosis progression induced by bleomycin (BLM). Collectively, these results suggested that overexpression of HSP70 attenuated pulmonary fibrosis induced by BLM in C57BL/6 mice and EMT process induced by TGF-β1 through NF-κB/NOX4/ROS pathway in vitro. Thus, HSP70 might be a potential therapeutic strategy for human lung fibrosis.

GGA (geranylgeranylacetone) ameliorates bleomycin-induced lung inflammation and pulmonary fibrosis by inhibiting apoptosis and oxidative stress

BACKGROUND

Fibrosis is a response to ongoing cellular injury, disruption, and tissue remodeling, the pathogenesis of which is unknown, and is characterized by extracellular matrix deposition. The antifibrotic effect of Geranylgeranylacetone (GGA), as an inducer of Heat shock protein 70 (HSP70), in liver, kidney and pulmonary fibrosis has been supported by multiple preclinical evidence. However, despite advances in our understanding, the precise roles of HSP70 in fibrosis require further investigation. The purpose of this study was to investigate whether GGA could participate in the progression of pulmonary fibrosis in mice through apoptosis, oxidative stress and inflammation.

METHODS AND RESULTS

B-cell lymphoma-2(Bcl-2) and Bcl2-Associated X (Bax) are two proteins related to apoptosis. Anti-apoptotic factor Bcl-2 and pro-apoptotic factor Bax are often involved in the apoptotic process in the form of dimer. Immunofluorescence and Western blot results showed that bleomycin (BLM) and transforming growth factor-β (TGF-β) inhibited Bcl-2 expression and promoted Bax expression in vitro and in vivo, respectively. In contrast, GGA treatment reverses this change. Reactive oxygen species (ROS), Malondialdehyde (MDA) and superoxide dismutase (SOD) are markers of oxidative stress, which often reflect oxidative injury of cells. The detection of ROS, MDA and SOD expression showed that TGF-β and BLM treatment could significantly promote oxidative stress, while GGA treatment could alleviate oxidative stress damage. In addition, BLM significantly elevated Tumor necrosis factor-α(TNF-α), Interleukin1β (IL-1β) and Interleukin 6 (IL-6), while scutellarin reversed the above alterations except for that of GGA.

RESULTS

Taken together, GGA suppressed apoptotic, oxidative stress and inflammation in BLM-induced pulmonary fibrosis.

Immune Mechanisms of Pulmonary Fibrosis with Bleomycin

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

Autophagy modulation by irbesartan mitigates the pulmonary fibrotic alterations in bleomycin challenged rats: Comparative study with rapamycin

AIMS

In pulmonary fibrosis, autophagy handles the maintenance of alveolar epithelial cells, prevents epithelial-mesenchymal transition (EMT), and controls collagen turnover. The mammalian target of rapamycin (mTOR) and its translational-dependent proteins are essential regulators of autophagy. Irbesartan (IRB) has earlier ameliorative effects in experimental pulmonary fibrosis. The current study aimed to explore therapeutic autophagy-modulated pulmonary fibrotic changes by IRB versus rapamycin (RAPA) in bleomycin (BLM)-challenged rats.

MATERIALS AND METHODS

A single intratracheal BLM dose at day (0), IRB in different doses (10, 20, and 40 mg/kg) or RAPA (2.5 mg/kg) was given daily for 14 continuous days.

KEY FINDINGS

IRB significantly diminished the fibrotic lung scores. Pulmonary levels of transforming growth factor (TGF)-β1 and hydroxyproline exhibited marked attenuation in IRB (40 mg/kg)-treated rats compared to other treated groups. IRB (40 mg/kg) was not significantly different from RAPA. It downregulated the fibrotic lung phosphorylated mammalian target of rapamycin (p-mTOR) levels and augmented lung Unc-51-like autophagy activating kinase 1 (ULK1), LC3-I and LC3-II more than IRB (10 and 20 mg/kg)-treated fibrotic groups.

SIGNIFICANCE

Autophagic effects via the mTOR signalling pathway may play a role in IRB's antifibrotic effects. Consideration of IRB as a therapeutic antifibrotic agent in pulmonary fibrosis needs further experimental and clinical long-term validation, especially in comorbid with primary hypertension, heart failure, and diabetic renal insults.

Association Between Antihypertensive Use and Hospitalized Pneumonia in Patients With Stroke: A Korean Nationwide Population-Based Cohort Study

BACKGROUND

We aimed to examine the association between antihypertensive use and the incidence of hospitalized pneumonia in patients with a history of stroke.

METHODS

In this case-crossover study, we obtained data from the Korean National Health Insurance Service-National Sample Cohort database. We included the data of patients with history of stroke who were admitted with a disease code of pneumonia. We analyzed the patients' exposure to antihypertensives in the 30 (single case period), 90-120, and 150-180 days (2 control periods) before the onset of pneumonia using conditional logistic regression analysis. Additionally, sensitivity analysis and subgroup analysis according to diabetes status, age, and documented disability were performed.

RESULTS

Angiotensin II receptor blocker (ARB) use was associated with a reduced risk of hospitalized pneumonia (adjusted odds ratio [OR] [95% confidence interval; 95% CI]: 0.718 [0.576-0.894]). However, the use of angiotensin converting enzyme inhibitors and other antihypertensives were not associated with a change in hospitalized pneumonia incidence (adjusted OR [95% CI]: 0.902, [0.603-1.350] and 0.788 [0609-1.018], respectively). Subgroup analysis revealed that ARB use was associated with a reduced incidence of hospitalized pneumonia in patients with a history of stroke who were older than 65 years, but not in younger (≤ 65 years) group (adjusted OR [95% CI]: 0.687 [0.536-0.880]).

CONCLUSION

ARB use is associated with a reduced incidence of hospitalized pneumonia in patients with a history of stroke, especially in older adults.

Olmesartan Attenuates Single-Lung Ventilation Induced Lung Injury via Regulating Pulmonary Microbiota

Single-lung ventilation (SLV) associated acute lung injury is similar to ischemia reperfusion (IR) injury which is usually occurred during lung surgery. Olmesartan (Olm), a novel angiotensin receptor blocker (ARB), has been reported to ameliorate organ IR injury. Several recent studies have shown that lung microbiota may be involved in pulmonary diseases, but the effect of pulmonary microbiota in SLV-induced lung injury has not been reported. This study aims to determine the mechanism of how Olm attenuates SLV induced lung injury. Our data showed that 7 days Olm treatment before modeling markedly alleviated SLV-induced lung injury by suppressing inflammation and reactive oxygen species. Bronchoalveolar lavage fluid samples from the injured side were collected for 16S rRNA gene-based sequencing analysis and 53 different bacteria at the genus and species levels were identified. Furthermore, the injured lung samples were collected for metabolomics analysis using liquid chromatography-mass spectrometry analyses to explore differential metabolites. The Kyoto Encyclopedia of Genes and Genomes (KEGG) was applied to analyze the correlation between differential metabolites and lung microbiota. A total of 38 pathways were identified according to differential metabolites and 275 relevant pathways were enriched via analyzing the microbial community, 24 pathways were both identified by analyzing either metabolites or microbiota, including pyrimidine metabolism, purine metabolism, aminoacyl-tRNA biosynthesis and ATP-binding cassette transporter. Besides classical blockage of the renin-angiotensin II system, Olm could also alleviate SLV-induced lung injury by rewiring the interaction between pulmonary microbiota and metabolites.

Development of mode of action networks related to the potential role of PPARγ in respiratory diseases

The peroxisome proliferator-activated receptor γ (PPARγ) is a key transcription factor, operating at the intercept of metabolic control and immunomodulation. It is ubiquitously expressed in multiple tissues and organs, including lungs. There is a growing body of information supporting the role of PPARγ signalling in respiratory diseases. The aim of the present study was to develop mode of action (MoA) networks reflecting the relationships between PPARγ signalling and the progression/alleviation of a spectrum of lung pathologies. Data mining was performed using the resources of the NIH PubMed and PubChem information systems. By linking available data on pathological/therapeutic effects of PPARγ modulation, knowledge-based MoA networking at different levels of biological organization (molecular, cellular, tissue, organ, and system) was performed. Multiple MoA networks were developed to relate PPARγ modulation to the progress or the alleviation of pulmonary disorders, triggered by diverse pathogenic, genetic, chemical, or mechanical factors. Pharmacological targeting of PPARγ signalling was discussed with regard to ligand- and cell type-specific effects in the context of distinct disease inductor- and disease stage-dependent patterns. The proposed MoA networking analysis allows for a better understanding of the potential role of PPARγ modulation in lung pathologies. It presents a mechanistically justified basis for further computational, experimental, and clinical monitoring studies on the dynamic control of PPARγ signalling in respiratory diseases.

The Role of Hypertension and Renin-angiotensin-aldosterone System Inhibitors in Bleomycin-induced Lung Injury

INTRODUCTION

The risk factors for bleomycin-induced lung injury (BLI), a fatal complication of cancer chemotherapy, are not well-established. The renin-angiotensin-aldosterone system (RAAS) has recently been suggested to play a role in the development of lung injury. This study clarified the impact of hypertension (HTN) and the administration of RAAS inhibitors on BLI occurrence in patients treated with bleomycin-containing regimens.

PATIENTS AND METHODS

We retrospectively analyzed the data of 190 patients treated with a bleomycin-containing regimen for Hodgkin lymphoma or germ cell tumors at our institutions from 2004 to 2018.

RESULTS

Overall, 190 patients received bleomycin, and symptomatic BLI occurred in 21 (11.1%) cases. In the multivariate analysis, age ≥ 65 years (odd ratio, 10.90; 95% confidence interval, 3.72-32.20; P < .001) and history of HTN (odds ratio, 3.32; 95% confidence interval, 1.07-10.30; P = .04) were found to be significant risk factors for BLI onset. BLI occurred in 3.6% (n = 5) of patients with no risk, 11.8% (n = 2) of those whose only risk factor was HTN, 31.6% (n = 6) of those whose only risk factor was age ≥ 65 years, and 57.1% (n = 8) of those with both risk factors (P < .001). BLI-induced mortality rates in each group were 0.0% (n = 0), 5.9% (n = 1), 10.5% (n = 2), and 42.9% (n = 6) (P < .001), respectively. Among 31 patients with HTN, BLI incidence was 12.5% in patients who were administered RAAS inhibitors and 53.3% in those who were not (P = .02).

CONCLUSION

Older age and history of HTN were independent risk factors for the development of BLI, and the administration of RAAS inhibitors might reduce the onset of BLI.

Candesartan could ameliorate the COVID-19 cytokine storm

BACKGROUND

Angiotensin receptor blockers (ARBs) reducing inflammation and protecting lung and brain function, could be of therapeutic efficacy in COVID-19 patients.

METHODS

Using GSEA, we compared our previous transcriptome analysis of neurons injured by glutamate and treated with the ARB Candesartan (GSE67036) with transcriptional signatures from SARS-CoV-2 infected primary human bronchial epithelial cells (NHBE) and lung postmortem (GSE147507), PBMC and BALF samples (CRA002390) from COVID-19 patients.

RESULTS

Hundreds of genes upregulated in SARS-CoV-2/COVID-19 transcriptomes were similarly upregulated by glutamate and normalized by Candesartan. Gene Ontology analysis revealed expression profiles with greatest significance and enrichment, including proinflammatory cytokine and chemokine activity, the NF-kappa B complex, alterations in innate and adaptive immunity, with many genes participating in the COVID-19 cytokine storm.

CONCLUSIONS

There are similar injury mechanisms in SARS-CoV-2 infection and neuronal injury, equally reduced by ARB treatment. This supports the hypothesis of a therapeutic role for ARBs, ameliorating the COVID-19 cytokine storm.

Irbesartan ameliorates myocardial fibrosis in diabetic cardiomyopathy rats by inhibiting the TGFβ1/Smad2/3 pathway

Myocardial fibrosis (MF) is an important pathological change in diabetic cardiomyopathy. The aim of the present study was to investigate whether irbesartan serves a role in improving MF in a diabetic rat model. Fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels were measured in rats using biochemical methods. Heart weight index (HWI), left ventricular weight index (LVWI), left ventricular systolic pressure (LVSP) and left ventricular end-diastolic pressure (LVEDP) were also measured, whilst type I collagen and hydroxyproline content in myocardial tissue was quantified. Western blotting was used to measure the expression of transforming growth factor β1 (TGFβ1), phosphorylated (p)-Smad2/3 and collagen type I α 1 chain (COL1A1) inmyocardial tissues or rat cardiac fibroblast (RCF) cells. Cell proliferation was measured using EdU staining. Procollagen type III N-terminal peptide (PIIINP) content, FBG, TC, TG and LDL-C levels were found to be significantly higher, whilst HDL-C levels were found to be significantly lower in rats in the diabetic group. Those in the diabetic group also exhibited significantly elevated HWI, LVWI, LVEDP, myocardial tissue type I collagen content and hydroxyproline content values, but significantly reduced LVSP. Changes in the aforementioned indicators were reversed after treatment with irbesartan, where the protein expression levels of TGFβ1 and p-Smad2/3 in myocardial tissue were also significantly reduced. In RCF cells, irbesartan significantly reversed high glucose-induced upregulation of TGFβ1 expression, Smad2/3 phosphorylation and COL1A1 expression, as well as reducing cell proliferation and rat type I PICP and PIIINP levels. Application of pirfenidone produced additive effects on reducing the expression levels of the proteins aforementioned when combined with irbesartan. Therefore, the present results demonstrated that irbesartan reduced the activity of the TGFβ1/Smad2/3 pathway and ameliorated diabetic MF by downregulating the expression of TGFβ1.

Association of Angiotensin Modulators With the Course of Idiopathic Pulmonary Fibrosis

BACKGROUND

Angiotensin peptides have been implicated in idiopathic pulmonary fibrosis (IPF) pathogenesis. Angiotensin modulators are used to treat arterial hypertension, a frequent comorbidity of IPF. This post hoc analysis evaluated associations of antihypertensive treatments with disease-related outcomes in IPF.

METHODS

All patients randomized to placebo (n = 624) in the CAPACITY and ASCEND studies were categorized by antihypertensive treatment at baseline. Outcomes of disease progression (first occurrence of ≥ 10% absolute decline in % predicted FVC, ≥ 50-m decline in 6-min walk distance, or death) and all-cause mortality were assessed over 52 weeks.

RESULTS

At baseline, 111 and 121 patients were receiving an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin II receptor blocker (ARB), respectively; 392 were receiving neither. In multivariable analyses adjusted for differences in baseline characteristics compared with the non-ACEi/ARB group, ACEi treatment (hazard ratio [HR], 0.6 [95% CI, 0.4-0.9]; P = .026), but not ARB (HR, 0.9 [95% CI, 0.6-1.2]; P = .413), was associated with slower disease progression. Furthermore, the increase in all-cause mortality associated with cardiovascular disease was not observed in the ACEi group (HR, 1.1 [95% CI, 0.5-2.9]; P = .782), which presented a similar percentage of IPF-related mortality as the non-ACEi/ARB group (3.6% vs 3.6%). In contrast, patients in the ARB group had greater risk of all-cause mortality (HR, 2.5 [95% CI, 1.2-5.2]). These observations were validated in a pooled analysis that included patients from the INSPIRE trial.

CONCLUSIONS

Prospective clinical trials are needed to evaluate whether angiotensin modulators may be beneficial to clinical outcomes in IPF.

TRIAL REGISTRY

ClinicalTrials.gov; Nos.: NCT01366209, NCT00287716, NCT00287729, NCT00075998; URL: www.clinicaltrials.gov).

Suppressive effects of type I angiotensin receptor antagonists, candesartan and irbesartan on allergic asthma

The effects of candesartan and irbesartan, antagonists of the type I angiotensin II receptor, were investigated on allergic asthma. The antigen-induced degranulation was measured by evaluating β-hexosaminidase activity in vitro. Additionally, a murine ovalbumin-induced allergic asthma model was used to test the in vivo efficacy. It was observed that while candesartan inhibited the antigen-induced degranulation in rat RBL-2H3 mast cells, irbesartan did not. Administration of candesartan and irbesartan decreased the number of immune cells in the bronchoalveolar lavage fluid and reduced the expression of Th2 (IL-4, IL-5, and IL-13) and Th1 cytokines (IL-2 and IFN-γ) in the lung tissues of mice with ovalbumin-induced allergic asthma. Histological studies revealed that both antagonists reduced inflammation and mucin production in the lungs. Therefore, these findings provide evidence that candesartan and irbesartan could have potential applications as anti-allergic agents.

Cannabidiol prevents haloperidol-induced vacuos chewing movements and inflammatory changes in mice via PPARγ receptors

The chronic use of drugs that reduce the dopaminergic neurotransmission can cause a hyperkinetic movement disorder called tardive dyskinesia (TD). The pathophysiology of this disorder is not entirely understood but could involve oxidative and neuroinflammatory mechanisms. Cannabidiol (CBD), the major non-psychotomimetic compound present in Cannabis sativa plant, could be a possible therapeutic alternative for TD. This phytocannabinoid shows antioxidant, anti-inflammatory and antipsychotic properties and decreases the acute motor effects of classical antipsychotics. The present study investigated if CBD would attenuate orofacial dyskinesia, oxidative stress and inflammatory changes induced by chronic administration of haloperidol in mice. Furthermore, we verified in vivo and in vitro (in primary microglial culture) whether these effects would be mediated by PPARγ receptors. The results showed that the male Swiss mice treated daily for 21 days with haloperidol develop orofacial dyskinesia. Daily CBD administration before each haloperidol injection prevented this effect. Mice treated with haloperidol showed an increase in microglial activation and inflammatory mediators in the striatum. These changes were also reduced by CBD. On the other hand, the levels of the anti-inflammatory cytokine IL-10 increased in the striatum of animals that received CBD and haloperidol. Regarding oxidative stress, haloperidol induced lipid peroxidation and reduced catalase activity. This latter effect was attenuated by CBD. The combination of CBD and haloperidol also increased PGC-1α mRNA expression, a co-activator of PPARγ receptors. Pretreatment with the PPARγ antagonist, GW9662, blocked the behavioural effect of CBD in our TD model. CBD also prevented LPS-stimulated microglial activation, an effect that was also antagonized by GW9662. In conclusion, our results suggest that CBD could prevent haloperidol-induced orofacial dyskinesia by activating PPARγ receptors and attenuating neuroinflammatory changes in the striatum.

Pathogenesis of systemic sclerosis: recent insights of molecular and cellular mechanisms and therapeutic opportunities

Systemic sclerosis (SSc) is a complex disease characterized by early microvascular abnormalities, immune dysregulation and chronic inflammation, and subsequent fibrosis of the skin and internal organs. Excessive fibrosis, distinguishing hallmark of SSc, is the end result of a complex series of interlinked vascular injury and immune activation, and represents a maladaptive repair process. Activated vascular, epithelial, and immune cells generate pro-fibrotic cytokines, chemokines, growth factors, lipid mediators, autoantibodies, and reactive oxygen species. These paracrine and autocrine cues in turn induce activation, differentiation, and survival of mesenchymal cells, ensuing tissue fibrosis through increased collagen synthesis, matrix deposition, tissue rigidity and remodeling, and vascular rarefaction. This review features recent insights of the pathogenic process of SSc, highlighting three major characteristics of SSc, microvasculopathy, excessive fibrosis, and immune dysregulation, and sheds new light on the understanding of molecular and cellular mechanisms contributing to the pathogenesis of SSc and providing novel avenues for targeted therapies.

Novel Anti-fibrotic Therapies

Fibrosis is a major player in cardiovascular disease, both as a contributor to the development of disease, as well as a post-injury response that drives progression. Despite the identification of many mechanisms responsible for cardiovascular fibrosis, to date no treatments have emerged that have effectively reduced the excess deposition of extracellular matrix associated with fibrotic conditions. Novel treatments have recently been identified that hold promise as potential therapeutic agents for cardiovascular diseases associated with fibrosis, as well as other fibrotic conditions. The purpose of this review is to provide an overview of emerging antifibrotic agents that have shown encouraging results in preclinical or early clinical studies, but have not yet been approved for use in human disease. One of these agents is bone morphogenetic protein-7 (BMP7), which has beneficial effects in multiple models of fibrotic disease. Another approach discussed involves altering the levels of micro-RNA (miR) species, including miR-29 and miR-101, which regulate the expression of fibrosis-related gene targets. Further, the antifibrotic potential of agonists of the peroxisome proliferator-activated receptors will be discussed. Finally, evidence will be reviewed in support of the polypeptide hormone relaxin. Relaxin is long known for its extracellular remodeling properties in pregnancy, and is rapidly emerging as an effective antifibrotic agent in a number of organ systems. Moreover, relaxin has potent vascular and renal effects that make it a particularly attractive approach for the treatment of cardiovascular diseases. In each case, the mechanism of action and the applicability to various fibrotic diseases will be discussed.

Cells and Culture Systems Used to Model the Small Airway Epithelium

The pulmonary epithelium is divided into upper, lower, and alveolar (or small) airway epithelia and acts as the mechanical and immunological barrier between the external environment and the underlying submucosa. Of these, the small airway epithelium is the principal area of gas exchange and has high immunological activity, making it a major area of cell biology, immunology, and pharmaceutical research. As animal models do not faithfully represent the human pulmonary system and ex vivo human lung samples have reliability and availability issues, cell lines, and primary cells are widely used as small airway epithelial models. In vitro, these cells are mostly cultured as monolayers (2-dimensional cultures), either media submerged or at air-liquid interface. However, these 2-dimensional cultures lack a three dimension-a scaffolding extracellular matrix, which establishes the intercellular network in the in vivo airway epithelium. Therefore, 3-dimensional cell culture is currently a major area of development, where cells are cultured in a matrix or are cultured in a manner that they develop ECM-like scaffolds between them, thus mimicking the in vivo phenotype more faithfully. This review focuses on the commonly used small airway epithelial cells, their 2-dimensional and 3-dimensional culture techniques, and their comparative phenotype when cultured under these systems.

Cardiovascular and antacid treatment and mortality in oxygen-dependent pulmonary fibrosis: A population-based longitudinal study

BACKGROUND AND OBJECTIVE

Severe idiopathic pulmonary fibrosis is associated with an increased risk of cardiovascular disease and gastro-oesophageal reflux, which may influence prognosis. We evaluated associations between cardiovascular and antacid medications, and mortality, in oxygen-dependent pulmonary fibrosis (PF) of unknown cause.

METHODS

Prospective population-based study of adults starting long-term oxygen therapy (LTOT) for PF in Sweden 2005-2009. PF of unknown cause was defined by excluding patients with known or probable secondary PF. Time-dependent associations between medications and all-cause mortality were analysed using extended Cox regression, adjusting for potential confounders including age, sex, vital capacity, blood gases, body mass index, performance status, comorbidity and concurrent medications.

RESULTS

Of 462 included patients, 329 (71%) died under observation. No patient was lost to follow-up. Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEI/ARB) were associated with reduced adjusted mortality (HR 0.63; 0.47-0.85) and antiplatelet drugs with increased mortality (HR 1.49; 1.11-2.00), largely driven by higher mortality in women. There were no associations with mortality for antacid treatments, β-blockers, diuretics or statins.

CONCLUSION

In oxygen-dependent PF, treatment with ACEI/ARB was associated with improved survival, antiplatelet drugs with decreased survival, whereas there was no association between antacid, β-blocker, diuretic or statin treatment and survival.

Inferring new drug indications using the complementarity between clinical disease signatures and drug effects

BACKGROUND

Drug repositioning is the process of finding new indications for existing drugs. Its importance has been dramatically increasing recently due to the enormous increase in new drug discovery cost. However, most of the previous molecular-centered drug repositioning work is not able to reflect the end-point physiological activities of drugs because of the inherent complexity of human physiological systems.

METHODS

Here, we suggest a novel computational framework to make inferences for alternative indications of marketed drugs by using electronic clinical information which reflects the end-point physiological results of drug's effects on the biological activities of humans. In this work, we use the concept of complementarity between clinical disease signatures and clinical drug effects. With this framework, we establish disease-related clinical variable vectors (clinical disease signature vectors) and drug-related clinical variable vectors (clinical drug effect vectors) by applying two methodologies (i.e., statistical analysis and literature mining). Finally, we assign a repositioning possibility score to each disease-drug pair by the calculation of complementarity (anti-correlation) and association between clinical states ("up" or "down") of disease signatures and clinical effects ("up", "down" or "association") of drugs. A total of 717 clinical variables in the electronic clinical dataset (NHANES), are considered in this study.

RESULTS

The statistical significance of our prediction results is supported through two benchmark datasets (Comparative Toxicogenomics Database and Clinical Trials). We discovered not only lots of known relationships between diseases and drugs, but also many hidden disease-drug relationships. For example, glutathione and edetic-acid may be investigated as candidate drugs for asthma treatment. We examined prediction results by using statistical experiments (enrichment verification, hyper-geometric and permutation test P<0.009 in Comparative Toxicogenomics Database and Clinical Trials) and presented evidences for those with already published literature.

CONCLUSION

The results show that electronic clinical information is a feasible data resource and utilizing the complementarity (anti-correlated relationships) between clinical signatures of disease and clinical effects of drugs is a potentially predictive concept in drug repositioning research. It makes the proposed approach useful to identity novel relationships between diseases and drugs that have a high probability of being biologically valid.

Targeting complement anaphylatoxin C5a receptor in hyperoxic lung injury in mice

Receptor binding of complement anaphylatoxin C5a results in proinflammatory activation of numerous diseases, but the role of receptor-mediated action during hyperoxic lung injury has, to the best of our knowledge, not yet been investigated. The contribution of the C5a receptor (C5aR) to hyperoxic lung injury in mice was investigated in this study. The effect of C5aR on hyperoxic lung injury in Balb/c mice was examined employing a C5aR antagonist (C5aRA). The mice were ventilated with 100% oxygen for 36 h with or without the administration of C5aRA. C5aR expression levels in non‑treated or 100% oxygen-treated mice were assessed by reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry. The body weight and the relative lung weight of the mice, and the morphological changes in the lung were then determined. The total cell counts and the number of macrophages, neutrophils and lymphocytes in bronchoalveolar lavage fluid (BALF) were determined using cytocentrifuge slides and a hemocytometer. The levels of interleukin-6 (IL-6), monocyte chemotactic protein (MCP-1) and tumor necrosis factor-α (TNF-α) in BALF and the myeloperoxidase (MPO) activity in the lung tissue were measured by enzyme-linked immunosorbent assay. The relative levels of CD68 and F4/80 messenger ribonucleic acid (mRNA) expression in the lung tissue were detected by RT-PCR. The TNF-α, IL-6 and MCP-1 protein expression levels in the lung tissue were assessed by western blot analysis. The results revealed hyperoxia-induced morphological changes, lung injury and increased expression levels of C5aR in lung tissue. The hyperoxia-induced increases in the total cell count and the number of macrophages, neutrophils and lymphocytes in the BALF were all significantly reduced in the mice receiving C5aRA. Treatment with C5aRA also attenuated the morphological changes and reduced MPO activity, and CD68 and F4/80 mRNA expression levels in the lung tissue, as well as the levels of IL-6, MCP-1 and TNF-α in BALF and lung tissue. In conclusion, C5a-C5aR action accelerated hyperoxia-induced lung injury, but this hyperoxic lung injury was attenuated by treatment with C5aRA.

Complement anaphylatoxin C4a inhibits C5a-induced neointima formation following arterial injury

Interactions between complement anaphylatoxins have been investigated in numerous fields; however, their functions during arterial remodeling following injury have not been studied. The inhibitory effect of complement anaphylatoxin C4a on neointima formation induced by C5a following arterial injury was investigated. Mice were subjected to wire-induced endothelial denudation of the femoral artery and treated with C5a alone or C5a + C4a for two weeks. C4a significantly inhibited C5a-induced neointima formation and the expression of CD68, F4/80, tumor necrosis factor-α (TNF‑α), interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1). In vitro, although C4a did not directly inhibit the migration, proliferation or the expression of vascular cell adhesion molecule-1 (VCAM-1) of C5a-induced vascular smooth muscle cells (VSMCs), C5a-pretreated conditioned medium‑induced migration, proliferation and VCAM-1 expression of VSMCs were suppressed when VSMCs were exposed to conditioned medium from C4a-pretreated macrophages. In addition, C5a-induced TNF-α, IL-6 and MCP-1 expression, Ca2+ influx and extracellular signal-regulated kinase (ERK) activation in macrophages were suppressed by C4a. C4a inhibits C5a-induced neointima formation, not by acting directly on VSMCs, but via a macrophage-mediated reaction by inhibiting the Ca2+-dependent ERK pathway in macrophages.

Spironolactone attenuates bleomycin-induced pulmonary injury partially via modulating mononuclear phagocyte phenotype switching in circulating and alveolar compartments

Background

Recent experimental studies provide evidence indicating that manipulation of the mononuclear phagocyte phenotype could be a feasible approach to alter the severity and persistence of pulmonary injury and fibrosis. Mineralocorticoid receptor (MR) has been reported as a target to regulate macrophage polarization. The present work was designed to investigate the therapeutic potential of MR antagonism in bleomycin-induced acute lung injury and fibrosis.

Methodology/Principal Findings

We first demonstrated the expression of MR in magnetic bead-purified Ly6G-/CD11b+ circulating monocytes and in alveolar macrophages harvested in bronchoalveolar lavage fluid (BALF) from C57BL/6 mice. Then, a pharmacological intervention study using spironolactone (20mg/kg/day by oral gavage) revealed that MR antagonism led to decreased inflammatory cell infiltration, cytokine production (downregulated monocyte chemoattractant protein-1, transforming growth factor β1, and interleukin-1β at mRNA and protein levels) and collagen deposition (decreased lung total hydroxyproline content and collagen positive area by Masson’ trichrome staining) in bleomycin treated (2.5mg/kg, via oropharyngeal instillation) male C57BL/6 mice. Moreover, serial flow cytometry analysis in blood, BALF and enzymatically digested lung tissue, revealed that spironolactone could partially inhibit bleomycin-induced circulating Ly6C^hi monocyte expansion, and reduce alternative activation (F4/80+CD11c+CD206+) of mononuclear phagocyte in alveoli, whereas the phenotype of interstitial macrophage (F4/80+CD11c-) remained unaffected by spironolactone during investigation.

Conclusions/Significance

The present work provides the experimental evidence that spironolactone could attenuate bleomycin-induced acute pulmonary injury and fibrosis, partially via inhibition of MR-mediated circulating monocyte and alveolar macrophage phenotype switching.