Comparative analysis of the alveolar macrophage proteome in ALI/ARDS patients between the exudative phase and recovery phase

Jingfang Granule alleviates bleomycin-induced acute lung injury via CD200-CD200R immunoregulatory pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Jingfang granules (JF), one famous traditional Chinese formula in "She Sheng Zhong Miao Fang" written by Shi-Che Zhang during the Ming Dynasty era, has been widely used to prevent epidemic diseases in history and now was recommended for the treatment of coronavirus disease 2019 (COVID-19) in China. However, the roles of JF against acute lung injury and its mechanisms remain unclear.

AIM OF THE STUDY

Acute lung injury (ALI) and its progressive acute respiratory distress syndrome (ARDS) are a continuum of lung inflammatory disease with high morbidity and mortality in clinic, especially in COVID-19 patients. The present study aims to investigate the effect of JF on ALI and clarify its underlying mechanisms for clinical application in COVID-19 control.

METHODS

Bleomycin-induced ALI mice were given oral gavage daily for seven days with or without Jingfang granules (2, 4 g/kg). The body weight, lung wet/dry weight ratios, lung appearance and tissue histopathology were evaluated. Quantitative real-time PCR, biochemical bronchoalveolar lavage fluids analysis was used to determine the gene expression of proinflammation factor and infiltrated inflammatory cells in lung. Immunofluorescence image and western blot were used to detect the markers of alveolar macrophages (AMs), endothelial cell apoptosis and changes of CD200-CD200R pathway.

RESULTS

Firstly, histopathological analysis showed that JF significantly attenuated pulmonary injury and inflammatory response in ALI mice. Then, cytokine detection, inflammatory cells assay, and JNKs and p38 pathway analysis indicated that the recruitment and activation of alveolar macrophages was the main reason to cause ALI and JF could reverse this variation. Next, immunofluorescence staining and TUNEL assay showed that JF upregulated the expression of CD200 and suppressed the apoptosis of alveolar endothelial cells. Finally, double immunofluorescence staining of CD200 and CD11c indicated that the seriously damaged tissue had the lower CD200 while more AMs infiltration, which was confirmed by RT-PCR analysis of CD200/CD200R.

CONCLUSIONS

Jingfang granules can protect lung from acu te injury and mitigate the recruitment and overactive AMs-induced inflammation via CD200-CD200R immunoregulatory signal axis, which will provide an experimental basis for Jingfang granules clinical applications in COVID-19.

Chemical exposure and alveolar macrophages responses: 'the role of pulmonary defense mechanism in inhalation injuries'

Epidemiological and clinical studies have indicated an association between particulate matter (PM) exposure and acute and chronic pulmonary inflammation, which may be registered as increased mortality and morbidity. Despite the increasing evidence, the pathophysiology mechanism of these PMs is still not fully characterised. Pulmonary alveolar macrophages (PAMs), as a predominant cell in the lung, play a critically important role in these pathological mechanisms. Toxin exposure triggers events associated with macrophage activation, including oxidative stress, acute damage, tissue disruption, remodelling and fibrosis. Targeting macrophage may potentially be employed to treat these types of lung inflammation without affecting the natural immune response to bacterial infections. Biological toxins, their sources of exposure, physical and other properties, and their effects on the individuals are summarised in this article. Inhaled particulates from air pollution and toxic gases containing chemicals can interact with alveolar epithelial cells and immune cells in the airways. PAMs can sense ambient pollutants and be stimulated, triggering cellular signalling pathways. These cells are highly adaptable and can change their function and phenotype in response to inhaled agents. PAMs also have the ability to polarise and undergo plasticity in response to tissue damage, while maintaining resistance to exposure to inhaled agents.

Periplaneta Americana Extract Ameliorates LPS-induced Acute Lung Injury Via Reducing Inflammation and Oxidative Stress

OBJECTIVE

Acute lung injury (ALI) is an acute clinical syndrome characterized by uncontrolled inflammation response, which causes high mortality and poor prognosis. The present study determined the protective effect and underlying mechanism of Periplaneta americana extract (PAE) against lipopolysaccharide (LPS)-induced ALI.

METHODS

The viability of MH-S cells was measured by MTT. ALI was induced in BALB/c mice by intranasal administration of LPS (5 mg/kg), and the pathological changes, oxidative stress, myeloperoxidase activity, lactate dehydrogenase activity, inflammatory cytokine expression, edema formation, and signal pathway activation in lung tissues and bronchoalveolar lavage fluid (BALF) were examined by H&E staining, MDA, SOD and CAT assays, MPO assay, ELISA, wet/dry analysis, immunofluorescence staining and Western blotting, respectively.

RESULTS

The results revealed that PAE obviously inhibited the release of proinflammatory TNF-α, IL-6 and IL-1β by suppressing the activation of MAPK/Akt/NF-κB signaling pathways in LPS-treated MH-S cells. Furthermore, PAE suppressed the neutrophil infiltration, permeability increase, pathological changes, cellular damage and death, pro-inflammatory cytokines expression, and oxidative stress upregulation, which was associated with its blockage of the MAPK/Akt/NF-κB pathway in lung tissues of ALI mice.

CONCLUSION

PAE may serve as a potential agent for ALI treatment due to its anti-inflammatory and anti-oxidative properties, which correlate to the blockage of the MAPK/NF-κB and AKT signaling pathways.

Clinical Value and Mechanism of Long Non-Coding RNA UCA1 in Acute Respiratory Distress Syndrome Induced by Cardiopulmonary Bypass

AIM

Long non-coding RNA (lncRNA) can be used as a biological marker for the diagnosis and treatment of various diseases. The study aimed to detect changes in the expression of lncRNA for urothelial carcinoma associated 1 (UCA1) in patients with cardiopulmonary bypass (CPB)-induced acute respiratory distress syndrome (ARDS). Clinical values and cell function in ARDS were explored.

METHOD

In total, 195 patients without CPB-induced ARDS were included in the control group, and 85 patients with ARDS were included in the ARDS group. Serum UCA1 levels were measured by quantitative real-time polymerase chain reaction. A549 was used for the cell experiments by establishing oxygen-glucose deprivation/reperfusion (OGD/R) cell models, and the cell viability and apoptosis were tested. The concentration of inflammatory factors was tested by an enzyme-linked immunosorbent assay. A luciferase reporting assay was applied for target gene analysis.

RESULTS

Quantitative real-time polymerase chain reaction revealed a gradual increase in serum UCA1 in both control and ARDS cases, and patients with ARDS had higher levels of UCA1 than those in the control group. Serum UCA1 was positively correlated with serum tumour necrosis factor-α and interleukin-6 concentration in patients with ARDS. UCA1 had the ability to distinguish patients with ARDS from those without it. UCA1 inhibition protected against lung injury and inhibited cell inflammation in vitro. MicroRNA (miR-182-5p) was downregulated in OGD/R-induced cell models and sponged by UCA1.

CONCLUSIONS

Elevated expression of UCA1 may be associated with the occurrence of ARDS after CPB surgery. The regulatory role of UCA1 in ARDS might be related to inflammation and downregulated miR-182-5p in alveolar epithelial cells.

Screening and Analysis of Serum Protein Biomarkers Infected by Coronavirus Disease 2019 (COVID-19)

Coronavirus disease 2019 (COVID-19) has spread widely around the world, and in-depth research on COVID-19 is necessary for biomarkers and target drug discovery. This analysis collected serum from six COVID-19-infected patients and six healthy people. The protein changes in the infected and healthy control serum samples were evaluated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatography (HPLC). The differential protein signature in both groups was retrieved and analyzed by the Kyoto Encyclopedia of Gene and Genomes (KEGG), Gene ontology, COG/KOG, protein-protein interaction, and protein domain interactions tools. We shortlisted 24 differentially expressed proteins between both groups. Ten genes were significantly up-regulated in the infection group, and fourteen genes were significantly down-regulated. The GO and KEGG pathway enrichment analysis suggested that the chromosomal part and chromosome were the most enriched items. The oxytocin signaling pathway was the most enriched item of KEGG analysis. The netrin module (non-TIMP type) was the most enriched protein domain in this study. Functional analysis of S100A9, PIGR, C4B, IL-6R, IGLV3-19, IGLV3-1, and IGLV5-45 revealed that SARS-CoV-2 was closely related to immune response.

Differential Protein Expression among Two Different Ovine ARDS Phenotypes-A Preclinical Randomized Study

Despite decades of comprehensive research, Acute Respiratory Distress Syndrome (ARDS) remains a disease with high mortality and morbidity worldwide. The discovery of inflammatory subphenotypes in human ARDS provides a new approach to study the disease. In two different ovine ARDS lung injury models, one induced by additional endotoxin infusion (phenotype 2), mimicking some key features as described in the human hyperinflammatory group, we aim to describe protein expression among the two different ovine models. Nine animals on mechanical ventilation were included in this study and were randomized into (a) phenotype 1, n = 5 (Ph1) and (b) phenotype 2, n = 4 (Ph2). Plasma was collected at baseline, 2, 6, 12, and 24 h. After protein extraction, data-independent SWATH-MS was applied to inspect protein abundance at baseline, 2, 6, 12, and 24 h. Cluster analysis revealed protein patterns emerging over the study observation time, more pronounced by the factor of time than different injury models of ARDS. A protein signature consisting of 33 proteins differentiated among Ph1/2 with high diagnostic accuracy. Applying network analysis, proteins involved in the inflammatory and defense response, complement and coagulation cascade, oxygen binding, and regulation of lipid metabolism were activated over time. Five proteins, namely LUM, CA2, KNG1, AGT, and IGJ, were more expressed in Ph2.

Sevoflurane suppresses NLRP3 inflammasome-mediated pyroptotic cell death to attenuate lipopolysaccharide-induced acute lung injury through inducing GSK-3β phosphorylation and activation

Pyroptosis is a type of programmed cell death, and pyroptosis-associated inflammatory response is closely associated with the pathogenesis of acute lung injury (ALI). Sevoflurane, a common clinical anesthetic, has been reported as therapeutic drug for ALI. However, the detailed mechanisms by which sevoflurane ameliorates ALI have not been fully delineated. In this study, we found that sevoflurane phosphorylated and activated the GSK-3β to suppress LPS-induced pyroptotic cell death, inflammation and ALI. Specifically, in the LPS-induced ALI mice models, sevoflurane attenuated lung damages and fibrosis, and restrained the production of the pro-inflammatory cytokines. Also, LPS increased the expression levels of pyroptosis-related proteins to promote pyroptotic cell death in ALI mice lung tissues, and LPS-induced pyroptotic cell death was reduced by sevoflurane co-treatment. Moreover, the potential underlying mechanisms were uncovered, and we illustrated that sevoflurane promoted GSK-3β activation in LPS-treated ALI mice lung tissues, and re-activation of GSK-3β by the PI3K/Akt pathway inhibitor LY294002 suppressed LPS-induced pyroptotic cell death in vivo. Consistently, in the in vitro macrophages, our data hinted that LPS-induced pyroptotic cell death were also reversed by sevoflurane. Collectively, the above results suggest that sevoflurane re-activated GSK-3β to suppress LPS-induced pyroptotic cell death, inflammation and ALI.

Codonopsis pilosula polysaccharide attenuates Escherichia coli-induced acute lung injury in mice

Acute lung injury (ALI) is an inflammatory lung disease could be caused by bacterial infection. Lipopolysaccharide (LPS), a prototype pathogen-associated molecular pattern (PAMP) from gram-negative bacteria such as Escherichia coli...

Personalized medicine using omics approaches in acute respiratory distress syndrome to identify biological phenotypes

In the last decade, research on acute respiratory distress syndrome (ARDS) has made considerable progress. However, ARDS remains a leading cause of mortality in the intensive care unit. ARDS presents distinct subphenotypes with different clinical and biological features. The pathophysiologic mechanisms of ARDS may contribute to the biological variability and partially explain why some pharmacologic therapies for ARDS have failed to improve patient outcomes. Therefore, identifying ARDS variability and heterogeneity might be a key strategy for finding effective treatments. Research involving studies on biomarkers and genomic, metabolomic, and proteomic technologies is increasing. These new approaches, which are dedicated to the identification and quantitative analysis of components from biological matrixes, may help differentiate between different types of damage and predict clinical outcome and risk. Omics technologies offer a new opportunity for the development of diagnostic tools and personalized therapy in ARDS. This narrative review assesses recent evidence regarding genomics, proteomics, and metabolomics in ARDS research.

Randomised, controlled, open label, multicentre clinical trial to explore safety and efficacy of hyperbaric oxygen for preventing ICU admission, morbidity and mortality in adult patients with COVID-19

INTRODUCTION

COVID-19 may cause severe pneumonitis and trigger a massive inflammatory response that requires ventilatory support. The intensive care unit (ICU)-mortality has been reported to be as high as 62%. Dexamethasone is the only of all anti-inflammatory drugs that have been tested to date that has shown a positive effect on mortality. We aim to explore if treatment with hyperbaric oxygen (HBO) is safe and effective for patients with severe COVID-19. Our hypothesis is that HBO can prevent ICU admission, morbidity and mortality by attenuating the inflammatory response. The primary objective is to evaluate if HBO reduces the number of ICU admissions compared with best practice treatment for COVID-19, main secondary objectives are to evaluate if HBO reduces the load on ICU resources, morbidity and mortality and to evaluate if HBO mitigates the inflammatory reaction in COVID-19.

METHODS AND ANALYSIS

A randomised, controlled, phase II, open label, multicentre trial. 200 subjects with severe COVID-19 and at least two risk factors for mortality will be included. Baseline clinical data and blood samples will be collected before randomisation and repeated daily for 7 days, at days 14 and 30. Subjects will be randomised with a computer-based system to HBO, maximum five times during the first 7 days plus best practice treatment or only best practice treatment. The primary endpoint, ICU admission, is defined by criteria for selection for ICU. We will evaluate if HBO mitigates the inflammatory reaction in COVID-19 using molecular analyses. All parameters are recorded in an electronic case report form. An independent Data Safety Monitoring Board will review the safety parameters.

ETHICS AND DISSEMINATION

The trial is approved by The National Institutional Review Board in Sweden (2020-01705) and the Swedish Medical Product Agency (5.1-2020-36673). Positive, negative and any inconclusive results will be published in peer-reviewed scientific journals with open access.

TRIAL REGISTRATION

NCT04327505. EudraCT number: 2020-001349-37.

The Role of Macrophages in the Pathogenesis of SARS-CoV-2-Associated Acute Respiratory Distress Syndrome

Macrophages are cells that mediate both innate and adaptive immunity reactions, playing a major role in both physiological and pathological processes. Systemic SARS-CoV-2-associated complications include acute respiratory distress syndrome (ARDS), disseminated intravascular coagulation syndrome, edema, and pneumonia. These are predominantly effects of massive macrophage activation that collectively can be defined as macrophage activation syndrome. In this review we focus on the role of macrophages in COVID-19, as pathogenesis of the new coronavirus infection, especially in cases complicated by ARDS, largely depends on macrophage phenotypes and functionalities. We describe participation of monocytes, monocyte-derived and resident lung macrophages in SARS-CoV-2-associated ARDS and discuss possible utility of cell therapies for its treatment, notably the use of reprogrammed macrophages with stable pro- or anti-inflammatory phenotypes.

Non-targeted proteomics of acute respiratory distress syndrome: clinical and research applications

Acute respiratory distress syndrome (ARDS) is characterized by refractory hypoxemia caused by accumulation of pulmonary fluid with a high mortality rate, but the underlying mechanism is not yet fully understood, causing absent specific therapeutic drugs to treat with ARDS. In recent years, more and more studies have applied proteomics to ARDS. Non-targeted studies of proteomics in ARDS are just beginning and have the potential to identify novel drug targets and key pathways in this disease. This paper will provide a brief review of the recent advances in the application of non-targeted proteomics to ARDS.

Can hyperbaric oxygen safely serve as an anti-inflammatory treatment for COVID-19?

INTRODUCTION

SARS-CoV-2 affects part of the innate immune response and activates an inflammatory cascade stimulating the release of cytokines and chemokines, particularly within the lung. Indeed, the inflammatory response during COVID-19 is likely the cause for the development of acute respiratory distress syndrome (ARDS). Patients with mild symptoms also show significant changes on pulmonary CT-scan suggestive of severe inflammatory involvement.

HYPOTHESIS

The overall hypothesis is that HBO2 is safe and reduces the inflammatory response in COVID-19 pneumonitis by attenuation of the innate immune system, increase hypoxia tolerance and thereby prevent organ failure and reduce mortality.

EVALUATION OF THE HYPOTHESIS

HBO2 is used in clinical practice to treat inflammatory conditions but has not been scientifically evaluated for COVID-19. Experimental and empirical data suggests that HBO2 may reduce inflammatory response in COVID-19. However, there are concerns regarding pulmonary safety in patients with pre-existing viral pneumonitis.

EMPIRICAL DATA

Anecdotes from "compassionate use" and two published case reports show promising results.

CONSEQUENCES OF THE HYPOTHESIS AND DISCUSSION

Small prospective clinical trials are on the way and we are conducting a randomized clinical trial.

GTS-21 Reduces Inflammation in Acute Lung Injury by Regulating M1 Polarization and Function of Alveolar Macrophages

BACKGROUND

Acute lung injury (ALI) is a severe outcome of sepsis. Alveolar macrophages (AMs) play key roles in defense, resolution in ALI. The polarization of AMs is dependent on micro environmental stimuli and might influence the progression of ALI. Gainesville Tokushima scientists (GTS)-21, a selective α7 nicotinic acetylcholine receptor agonist of the cholinergic anti-inflammatory pathway (CAP), has recently been established to be promising in the treatment of ALI. However, the molecular mechanism underlying the GTS-21-mediated suppression of inflammatory responses has been explored only partially. In this study, we examined the relation between GTS-21 and AM polarization in ALI.

METHODS

The adoptive transfer of M1 (classically activated) and M2 (alternatively activated)-polarized AMs was performed to AM-depleted ALI mice, along with the administration of GTS-21 in a murine model of lipopolysaccharide (LPS)-induced ALI and in isolated AMs that had been stimulated by LPS in vitro.

RESULTS

The adoptive transfer of M1-polarized AMs aggravated the inflammatory response in the lung in contrast to the adoptive transfer of M2-polarized AMs. GTS-21 protected the lung from the effect of LPS, preventing injury and decreasing the number of AMs, AM-related pro-inflammatory cytokine levels, high mobility group box 1 expression levels in AMs. In addition, GTS-21 significantly diminished the number of M1-polarized AM and increased the number of M2-polarized AM, by flow cytometry, RT-PCR, enzyme-linked immunosorbent assay, and the Arg1 and iNOS activity assays.

CONCLUSION

The GTS-21 substantially ameliorates LPS-induced ALI. This protection is predominantly associated with the inhibition of pulmonary AM M1 polarization and alteration in AM function.

Mdivi-1 attenuates lipopolysaccharide-induced acute lung injury by inhibiting MAPKs, oxidative stress and apoptosis

Sepsis is among the most devastating events in intensive care units. As a complication of sepsis, acute lung injury (ALI) is common and highly associated with poor outcome. The present study demonstrated that abnormal mitochondrial dynamics play a pivotal role in lipopolysaccharide (LPS)-induced ALI. Inhibiting the mitochondrial fission with the specific inhibitor-1 (Mdivi-1) ameliorated ALI as assessed by hematoxylin and eosin (H&E) staining and wet/dry ratio. Furthermore, Mdivi-1 reduced mitogen-activated protein kinases (MAPKs) activation, oxidative stress and apoptosis in the lungs. Plasma pro-inflammation cytokines were also reduced significantly in Mdivi-1-treated mice. In vitro study revealed that Mdivi-1 protected the macrophages from LPS-induced MAPKs activation, oxidative stress and cell apoptosis. Mdivi-1 also inhibited the release of pro-inflammatory cytokines. Morphological analysis showed that Mdivi-1 rescued the macrophages from LPS-induced mitochondrial fragmentation. Moreover, LPS treatment induced significant phosphorylation of Drp1 at Ser616, dephosphorylation at Ser637 and translocation of Drp1 from the cytoplasm to mitochondria, while Mdivi-1 inhibited those effects. Thus, modification of fission to rebuild mitochondrial homeostasis may offer an innovative opportunity for developing therapeutic strategies against ALI.

Macrophage Polarization Favors Epithelial Repair During Acute Respiratory Distress Syndrome

OBJECTIVES

Alveolar macrophage polarization and role on alveolar repair during human acute respiratory distress syndrome remain unclear. This study aimed to determine during human acute respiratory distress syndrome: the alveolar macrophage polarization, the effect of alveolar environment on macrophage polarization, and the role of polarized macrophages on epithelial repair.

DESIGN

Experimental ex vivo and in vitro investigations.

SETTING

Four ICUs in three teaching hospitals.

PATIENTS

Thirty-three patients with early moderate-to-severe acute respiratory distress syndrome were enrolled for assessment of the polarization of alveolar macrophages.

INTERVENTIONS

Polarization of acute respiratory distress syndrome macrophages was studied by flow cytometry and quantitative polymerase chain reaction. Modulation of macrophage polarization was studied in vitro using phenotypic and functional readouts. Macrophage effect on repair was studied using alveolar epithelial cells in wound healing models.

MEASUREMENTS AND MAIN RESULTS

Ex vivo, alveolar macrophages from early acute respiratory distress syndrome patients exhibited anti-inflammatory characteristics with high CD163 expression and interleukin-10 production. Accordingly, early acute respiratory distress syndrome-bronchoalveolar lavage fluid drives an acute respiratory distress syndrome-specific anti-inflammatory macrophage polarization in vitro, close to that induced by recombinant interleukin-10. Culture supernatants from macrophages polarized in vitro with acute respiratory distress syndrome-bronchoalveolar lavage fluid or interleukin-10 and ex vivo acute respiratory distress syndrome alveolar macrophages specifically promoted lung epithelial repair. Inhibition of the hepatocyte growth factor pathway in epithelial cells and hepatocyte growth factor production in macrophages both reversed this effect. Finally, hepatocyte growth factor and soluble form of CD163 concentrations expressed relatively to macrophage count were higher in bronchoalveolar lavage fluid from acute respiratory distress syndrome survivors.

CONCLUSIONS

Early acute respiratory distress syndrome alveolar environment drives an anti-inflammatory macrophage polarization favoring epithelial repair through activation of the hepatocyte growth factor pathway. These results suggest that macrophage polarization may be an important step for epithelial repair and acute respiratory distress syndrome recovery.

NETs promote ALI/ARDS inflammation by regulating alveolar macrophage polarization

Neutrophils activated during acute lung injury (ALI) form neutrophil extracellular traps (NETs) to capture pathogens. However, excessive NETs can cause severe inflammatory reactions. Macrophages are classified as M1 macrophages with proinflammatory effects or M2 macrophages with anti-inflammatory effects. During ALI, alveolar macrophages (AMs) polarize to the M1 phenotype. This study tested the hypothesis that NETs may aggravate ALI or acute respiratory distress syndrome (ARDS) inflammation by promoting alveolar macrophage polarization to the M1 type. Our research was carried out in three aspects: clinical research, animal experiments and in vitro experiments. We determined that NET levels in ARDS patients were positively correlated with M1-like macrophage polarization. NET formation was detected in murine ALI tissue and associated with increased M1 markers and decreased M2 markers in BALF and lung tissue. Treatment with NET inhibitors significantly inhibitor NETs generation, downregulated M1 markers and upregulated M2 markers. Regardless of LPS pre-stimulation, significant secretion of proinflammatory cytokines and upregulated M1 markers were detected from bone marrow-derived macrophages (M0 and M2) cocultured with high concentrations of NETs; conversely, M2 markers were downregulated. In conclusion, NETs promote ARDS inflammation during the acute phase by promoting macrophage polarization to the M1 phenotype. We propose that NETs play an important role in the interaction between neutrophils and macrophages during the early acute phase of ALI.

Dehydrocostus Lactone Suppresses LPS-induced Acute Lung Injury and Macrophage Activation through NF-κB Signaling Pathway Mediated by p38 MAPK and Akt

Acute lung injury (ALI) is a severe clinical disease marked by dysregulated inflammation response and has a high rate of morbidity and mortality. Macrophages, which play diverse roles in the inflammatory response, are becoming therapeutic targets in ALI. In this study we investigated the effects of dehydrocostus lactone (DHL), a natural sesquiterpene, on macrophage activation and LPS-induced ALI. The macrophage cell line RAW264.7 and primary lung macrophages were incubated with DHL (0, 3, 5, 10 and 30 μmol/L) for 0.5 h and then challenged with LPS (100 ng/mL) for up to 8 hours. C57BL/6 mice were intratracheally injected with LPS (5 mg/kg) to induce acute lung injury (ALI) and then treated with a range of DHL doses intraperitoneally (5 to 20 mg/kg). The results showed that DHL inhibited LPS-induced production of proinflammatory mediators such as iNOS, NO, and cytokines including TNF-α, IL-6, IL-1β, and IL-12 p35 by suppressing the activity of NF-κB via p38 MAPK/MK2 and Akt signaling pathway in macrophages. The in vivo results revealed that DHL significantly attenuated LPS-induced pathological injury and reduced cytokines expression in the lung. NF-κB, p38 MAPK/MK2 and Akt signaling molecules were also involved in the anti-inflammatory effect. Collectively, our findings suggested that DHL is a promising agent for alleviating LPS-induced ALI.

Blocking CXCL1-dependent neutrophil recruitment prevents immune damage and reduces pulmonary bacterial infection after inhalation injury

Smoke inhalation associated with structural fires, wildfires, or explosions leads to lung injury, for which innovative and clinically relevant animal models are needed to develop effective therapeutics. We have previously reported that damage-associated molecular patterns (DAMPs) and anti-inflammatory cytokines correlate with infectious complications in patients diagnosed with inhalational injury. In this study, we describe a novel and translational murine model of acute inhalational injury characterized by an accumulation of protein and neutrophils in the bronchoalveolar space, as well as histological evidence of tissue damage. Mice were anesthetized, and a cannula was placed in the trachea and exposed to smoldering plywood smoke three times for 2-min intervals in a smoke chamber. Here we demonstrate that this model recapitulates clinically relevant phenotypes, including early release of double-stranded DNA (dsDNA), IL-10, monocyte chemoattractant protein (MCP)-1, and CXCL1 along with neutrophilia early after injury, accompanied by subsequent susceptibility to opportunistic infection with Pseudomonas aeruginosa. Further investigation of the model, and in turn a reanalysis of patient samples, revealed a late release of the DAMP hyaluronic acid (HA) from the lung. Using nitric oxide synthase-deficient mice, we found that Nos2 was required for increases in IL-10, MCP-1, and HA following injury but not release of dsDNA, CXCL1 expression, early neutrophilia, or susceptibility to opportunistic infection. Depletion of CXCL1 attenuated early neutrophil recruitment, leading to decreased histopathology scores and improved bacterial clearance in this model of smoke inhalation. Together, these data highlight the potential therapeutic benefit of attenuating neutrophil recruitment in the first 24 h after injury in patients.

New Strategies and Challenges in Lung Proteomics and Metabolomics. An Official American Thoracic Society Workshop Report

This document presents the proceedings from the workshop entitled, "New Strategies and Challenges in Lung Proteomics and Metabolomics" held February 4th-5th, 2016, in Denver, Colorado. It was sponsored by the National Heart Lung Blood Institute, the American Thoracic Society, the Colorado Biological Mass Spectrometry Society, and National Jewish Health. The goal of this workshop was to convene, for the first time, relevant experts in lung proteomics and metabolomics to discuss and overcome specific challenges in these fields that are unique to the lung. The main objectives of this workshop were to identify, review, and/or understand: (1) emerging technologies in metabolomics and proteomics as applied to the study of the lung; (2) the unique composition and challenges of lung-specific biological specimens for metabolomic and proteomic analysis; (3) the diverse informatics approaches and databases unique to metabolomics and proteomics, with special emphasis on the lung; (4) integrative platforms across genetic and genomic databases that can be applied to lung-related metabolomic and proteomic studies; and (5) the clinical applications of proteomics and metabolomics. The major findings and conclusions of this workshop are summarized at the end of the report, and outline the progress and challenges that face these rapidly advancing fields.

High-dose dexamethasone induced LPS-stimulated rat alveolar macrophages apoptosis

Prolonged administration of an excessive dose of corticosteroids proved to be harmful for patients with acute lung injury (ALI). A previous study has found that repeated administration of an excessive dose of methylprednisolone reduced alveolar macrophages (AMs) in bronchoalveolar lavage fluid (BALF) with an unknown mechanism. This study aimed to investigate the effect of excessive use of dexamethasone (Dex) on BALF AMs in vitro. Transmission electron microscopy and DNA fragmentation analysis demonstrated that 10^-4 and 10^-5 M Dex induced lipopolysaccharide-stimulated rat AMs apoptosis with downregulation of tumor necrosis factor-α, interleukin (IL)-12 and upregulation of IL-10, transforming growth factor-β. These results indicated that apoptosis might be a novel contribution involved in the detrimental effect of excessive dose of Dex clinically used to treat ALI.

Lower airways inflammation in patients with ARDS measured using endotracheal aspirates: a pilot study

Introduction

Our knowledge of acute respiratory distress syndrome (ARDS) pathogenesis is incomplete. The goal of this pilot study is to investigate the feasibility of measuring lower airways inflammation in patients with ARDS using repeated endotracheal aspirates (ETAs).

Methods

ETAs were obtained within 24 hours by intensive care unit admission from 25 mechanically ventilated patients with ARDS and 10 of them underwent a second ETA within 96 hours after the first sampling. In each sample, cell viability was assessed using trypan blue exclusion method and the total and differential cell counts were measured using Neubauer-improved cell counting chamber and cytospins stained with Diff-Quik.

Results

The median cell viability was 89 (IQR 80–93)%, with a median total cell count of 305 (IQR 130–1270)×10³/mL and a median macrophage, neutrophil, lymphocyte and eosinophil count, respectively, of 19.8 (IQR 5.4–71.6)×10³/mL; 279 (IQR 109–1213)×10³/mL; 0 (IQR 0–0.188)×10³/mL; 0 (IQR 0–1.050)×10³/mL. Eosinophil count in the ETA correlated with the number of blood eosinophils (r=0.4840, p=0.0142). Cell viability and total and differential cell counts were neither significantly different in the second ETA compared with the first ETA nor were unaffected by the presence or absence of bacteria in the blood and/or ETA, or by the ARDS aetiology, apart from the macrophage count which was significantly increased in patients with ARDS associated with acute pancreatitis compared with those associated with pneumonia (p=0.0143).

Conclusions

ETA can be used to investigate the cellularity of the lower airways in patients with ARDS and it is an easy-to-perform and non-invasive procedure. Eosinophil counts in ETA and blood are significantly correlated. The number of macrophages in ETA may be affected by the aetiology of the ARDS.

Mass Spectrometry-based Proteomics in Acute Respiratory Distress Syndrome: A Powerful Modality for Pulmonary Precision Medicine

Objective:

Acute respiratory distress syndrome (ARDS) is an acute and lethal clinical syndrome that is characterized by hypoxemic respiratory failure and diffuse alveolar inflammatory damage. This review aimed to search and discuss the mass spectrometry (MS)-based proteomic studies on different subsets of ARDS patients.

Data Sources:

Original research articles were collected from the PubMed database published in English up to December 2015.

Study Selection:

The literature search was done using the term “(acute lung injury OR acute respiratory distress syndrome) AND (proteomics OR proteome OR mass spectrum OR differential in-gel electrophoresis OR two-dimensional polyacrylamide gel electrophoresis)”. Related original research articles were included and were carefully analyzed.

Results:

Eight original proteomic researches on ARDS patients were found. The common proteomic modalities were two-dimensional (2D) high-performance liquid chromatography-based electronic spray ion-MS/MS and 2D-polyacrylamide gel electrophoresis/differential in-gel electrophoresis-based matrix-assisted laser desorption ionization-time of flight/MS. They compared the proteome between ARDS patients and normal controls and analyzed the dynamic changes of proteome at different ARDS stages or severity. The disturbed proteome in ARDS patients includes plasma acute-phase proteins, inflammatory/immune-associated proteins, and coagulation proteins.

Conclusions:

Although several previous studies have provided some useful information about the lung proteome in ARDS patients and gained several interesting disease-associated biomarkers, clinical proteomic studies in ARDS patients are still in the initial stage. An increased cooperation is still needed to establish a global and faithful database containing disease-specific proteome from the largest ARDS subsets.

Deleted in malignant brain tumors 1 protein is a potential biomarker of acute respiratory distress syndrome induced by pneumonia

Acute respiratory distress syndrome (ARDS) is associated with high mortality and morbidity. Early diagnosis and risk stratification in patients with ARDS should improve prognosis. Unfortunately, no clinical biomarkers are available for use in early diagnosis. Quantitative proteomics is a powerful tool for biomarker discovery in cancer, autoimmune diseases, and ARDS. Here, we employed isobaric tags for relative and absolute quantitation (iTRAQ) technology to identify potential biomarkers for early ARDS diagnosis and predict the risk for increased disease severity induced by pneumonia. We collected the bronchoalveolar lavage fluid (BALF) and plasma from ARDS patients with differing degrees of ARDS severity. We identified 338 proteins dysregulated in ARDS through iTRAQ, 18 of which showed significant differences with at least 1.5-fold differential expression in patients with mild or severe ARDS. Differential plasma expression of pulmonary surfactant associated protein A, apolipoprotein A1, and deleted in malignant brain tumors 1 protein (DMBT1) was verified in plasma samples. Our results indicate that DMBT1 can potentially serve as a biomarker for early ARDS diagnosis and disease severity assessment.

Biomarkers of lung injury in cardiothoracic surgery

Diagnosis of pulmonary dysfunction is currently almost entirely based on a vast series of physiological changes, but comprehensive research is focused on determining biomarkers for early diagnosis of pulmonary dysfunction. Here we discuss the use of biomarkers of lung injury in cardiothoracic surgery and their ability to detect subtle pulmonary dysfunction in the perioperative period. Degranulation products of neutrophils are often used as biomarker since they have detrimental effects on the pulmonary tissue by themselves. However, these substances are not lung specific. Lung epithelium specific proteins offer more specificity and slowly find their way into clinical studies.