The predictive role of serum and bronchoalveolar lavage cytokines and adhesion molecules for acute respiratory distress syndrome development and outcome

Ameliorative effect of pedunculoside on sepsis-induced acute lung injury, inflammation and pulmonary fibrosis in mice model via suppressing AKT/NF-κB pathway

BACKGROUND/OBJECTIVES

Sepsis-induced acute lung injury (ALI) is the typical complications of sepsis with a high global incidence and mortality. Inhibition of inflammatory response is a crucial and effective strategy for sepsis-induced ALI. Pedunculoside (PE) has been shown to have an anti-inflammatory effect on various diseases. However, the effect and mechanism of PE on sepsis-induced ALI remain unknown.

MATERIALS/METHODS

A mice model of sepsis-induced ALI was constructed by cecal ligation and puncture (CLP). The effect of PE on the CLP-induced mice were assessed using pathological staining, terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL), reverse transcription quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA) and western blot assays.

RESULTS

PE reduced pathological symptoms and scores, apoptosis and the W/D ratio of lung tissues in CLP-induced mice. Besides, PE decreased the level of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α), pulmonary fibrosis and the expression of fibrosis markers. Mechanically, PE inhibited AKT/NF-κB signaling in CLP-induced mice. Activation of AKT/NF-κB pathway abolished the ameliorative effect of PE on the pathological symptoms, the release of inflammatory factors and pulmonary fibrosis of CLP-induced mice.

CONCLUSION

PE improved inflammation and pulmonary fibrosis by inhibiting AKT/NF-κB pathway in CLP-induced mice.

Acute Respiratory Distress Syndrome: Definition, Diagnosis, and Routine Management

Acute respiratory distress syndrome (ARDS) is an acute inflammatory lung injury characterized by severe hypoxemic respiratory failure, bilateral opacities on chest imaging, and low lung compliance. ARDS is a heterogeneous syndrome that is the common end point of a wide variety of predisposing conditions, with complex pathophysiology and underlying mechanisms. Routine management of ARDS is centered on lung-protective ventilation strategies such as low tidal volume ventilation and targeting low airway pressures to avoid exacerbation of lung injury, as well as a conservative fluid management strategy.

Biomarker Signatures of Severe Acute Kidney Injury in a Critically Ill Cohort of COVID-19 and Non-COVID-19 Acute Respiratory Illness

Kidney and lung injury are closely inter-related during acute respiratory illness, but the molecular risk factors that these organ injuries share are not well defined.

OBJECTIVES

We identified plasma biomarkers associated with severe acute kidney injury (AKI) during acute respiratory illness, and compared them to biomarkers associated with severe acute respiratory failure (ARF).

DESIGN SETTINGS AND PARTICIPANTS

Prospective observational cohort study enrolling March 2020 through May 2021, at three hospitals in a large academic health system. We analyzed 301 patients admitted to an ICU with acute respiratory illness.

MAIN OUTCOMES AND MEASURES

Outcomes were ascertained between ICU admission and day 14, and included: 1) severe AKI, defined as doubling of serum creatinine or new dialysis and 2) severe ARF, which included new or persistent need for high-flow oxygen or mechanical ventilation. We measured biomarkers of immune response and endothelial function, pathways related to adverse kidney and lung outcomes, in plasma collected within 24 hours of ICU admission. Severe AKI occurred in 48 (16%), severe ARF occurred in 147 (49%), and 40 (13%) patients experienced both. Two-fold higher concentrations of soluble tumor necrosis factor receptor-1 (sTNFR-1) (adjusted relative risk [aRR], 1.56; 95% CI, 1.24-1.96) and soluble triggering receptor on myeloid cells-1 (sTREM-1) (aRR, 1.85; 95% CI, 1.42-2.41), biomarkers of innate immune activation, were associated with higher risk for severe AKI after adjustment for age, sex, COVID-19, and Acute Physiology and Chronic Health Evaluation-III. These biomarkers were not significantly associated with severe ARF. Soluble programmed cell death receptor-1 (sPDL-1), a checkpoint pathway molecule, as well as soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular adhesion molecule-1 (sVCAM-1), molecules involved with endothelial-vascular leukocyte adhesion, were associated with both severe AKI and ARF.

CONCLUSIONS AND RELEVANCE

sTNFR-1 and sTREM-1 were linked strongly to severe AKI during respiratory illness, while sPDL-1, sICAM-1 and sVCAM-1 were associated with both severe AKI and ARF. These biomarker signatures may shed light on pathophysiology of lung-kidney interactions, and inform precision medicine strategies for identifying patients at high risk for these organ injuries.

Effect of preoperative pulse oximeter oxygen saturation on postoperative prolonged mechanical ventilation in patients with tetralogy of Fallot

Background

As an easily accessible and intervened clinical indicator, preoperative pulse oximeter oxygen saturation (SpO₂) is an important factor affecting the prognosis of patients with tetralogy of Fallot (TOF). However, whether SpO₂ is associated with postoperative mechanical ventilation (MV) time remains unknown. Therefore, this study aimed to investigate the impact of preoperative SpO₂ on postoperative prolonged mechanical ventilation (PMV) in children with TOF.

Materials and methods

The study included children younger than 18 years who underwent corrective operations for TOF between January 2016 and December 2018 in Fuwai Hospital, China. Univariate and multivariate logistic regression analyses were used to evaluate the influence of preoperative SpO₂ on postoperative PMV. After identifying SpO₂ as an independent risk factor for PMV, patients were further divided into two groups according to the cutoff value of SpO₂, and propensity score matching (PSM) analysis was used to eliminate the effect of confounding factors. The logistic regression was used to compare the outcomes between the two groups after PSM.

Results

A total of 617 patients were finally enrolled in this study. By the univariable and multivariate logistic analysis, four independent risk factors for PMV were determined, namely, SpO₂, surgical technique, aortic cross-clamp time, and intraoperative minimum temperature. According to the outcomes of 219 paired patients after PSM, the incidence of PMV was significantly higher in patients with lower preoperative SpO₂ (P = 0.022). Also, there was significant increase in mechanical ventilation time (P = 0.019), length of intensive care unit stay (P = 0.044), postoperative hospital stay (P = 0.006), hospital stay (P = 0.039), and hospitalization cost (P = 0.019) at the lower preoperative SpO₂ level.

Conclusion

Low preoperative SpO₂ represents an independent risk factor of postoperative PMV in children with TOF.

The exogenous surfactant pre-treatment attenuates ventilator-induced lung injury in adult rats

Mechanical ventilation is an essential supportive therapy in the treatment of critical patients, and it aims to maintain adequate gas exchange; however, it can also contribute to inflammation and oxidative stress, thus leading to lung injury. We tested the hypothesis that exogenous surfactant administration will be protective against ventilator-induced lung injury in adult healthy Wistar rats both because of its anti-inflammatory properties as well as its role in preventing alveolar collapse at end-expiration. Thus, the effect of intranasal instillation of a bovine exogenous surfactant was tested in Wistar rats submitted to mechanical ventilation. The animals were divided into four groups: (1) CONTROL; (2) SURFACTANT; (3) Mechanical ventilation (MV); (4) MV with pre-treatment with surfactant (MVSURFACTANT). The MV and MVSURFACTANT were submitted to MV with high tidal volume (12 mL/kg) for 1 h. After the experimental protocol, all animals were euthanized and the arterial blood, bronchoalveolar lavage fluid and lungs were collected for biochemical, immunoenzymatic assay, arterial blood gases, and morphometric analyzes. The Wistar rats that received exogenous surfactant (Survanta®) by intranasal instillation before MV demonstrated reduced levels of leukocytes, inflammatory biomarkers such as CCL2, IL-1, IL-6 and TNF-α. Furthermore, it prevented oxidative damage by reducing lipid peroxidation and protein carbonylation as well as histological pattern changes of pulmonary parenchyma. Our data indicate that exogenous surfactant attenuated lung inflammation and redox imbalance induced by mechanical ventilation in healthy adult rats suggesting a preventive effect on ventilator-induced lung injury.

Association of platelet count with all-cause mortality from acute respiratory distress syndrome: A cohort study

Background

The purpose of this study was to investigate whether platelet count was associated with mortality in acute respiratory distress syndrome (ARDS) patients.

Methods

We analyzed patients with ARDS from Multi‐parameter Intelligent Monitoring in Intensive Care Database III (MIMIC‐III). Platelet count was measured at the time of intensive care unit (ICU) admission. The cox proportional hazard model and subgroup analysis were used to determine the relationship between the platelet count and mortality of ARDS, as well as the consistency of its association. The primary outcome of this study was 365‐day mortality from the date of ICU admission.

Result

This study enrolled a total of 395 critically ill patients with ARDS. After adjustment for age, gender and ethnicity, the multivariate cox regression model showed that the hazard ratios (HRs) (95% confidence intervals [CIs]) of platelet count <192 × 10⁹/L and >296 × 10⁹/L were 2.08 (1.43, 3.04) and 1.35 (0.91, 2.01), respectively, compared with the reference (192–296 ×10⁹/L). After adjusting for confounding factors, lower platelet count (<192 × 10⁹/L) was associated with increased mortality (adjusted HR, 1.71; 95% CI 1.06–2.76, p = 0.0284). However, there was no similar trend in the 30‐day (adjusted HR,1.02; 95% CI 0.54–1.94) or 90‐day (adjusted HR, 1.65; 95% CI 0.94–2.89) mortality. In the subgroup analysis, lower platelet count showed significant interactions with specific populations (p interaction = 0.0413), especially in patients with atrial fibrillation.

Conclusion

Taken together, our analysis showed that platelet count is an independent predictor of mortality in critically ill patients with ARDS.

Colivelin, a synthetic derivative of humanin, ameliorates endothelial injury and glycocalyx shedding after sepsis in mice

Endothelial dysfunction plays a central role in the pathogenesis of sepsis-mediated multiple organ failure. Several clinical and experimental studies have suggested that the glycocalyx is an early target of endothelial injury during an infection. Colivelin, a synthetic derivative of the mitochondrial peptide humanin, has displayed cytoprotective effects in oxidative conditions. In the current study, we aimed to determine the potential therapeutic effects of colivelin in endothelial dysfunction and outcomes of sepsis in vivo. Male C57BL/6 mice were subjected to a clinically relevant model of polymicrobial sepsis by cecal ligation and puncture (CLP) and were treated with vehicle or colivelin (100-200 µg/kg) intraperitoneally at 1 h after CLP. We observed that vehicle-treated mice had early elevation of plasma levels of the adhesion molecules ICAM-1 and P-selectin, the angiogenetic factor endoglin and the glycocalyx syndecan-1 at 6 h after CLP when compared to control mice, while levels of angiopoietin-2, a mediator of microvascular disintegration, and the proprotein convertase subtilisin/kexin type 9, an enzyme implicated in clearance of endotoxins, raised at 18 h after CLP. The early elevation of these endothelial and glycocalyx damage biomarkers coincided with lung histological injury and neutrophil inflammation in lung, liver, and kidneys. At transmission electron microscopy analysis, thoracic aortas of septic mice showed increased glycocalyx breakdown and shedding, and damaged mitochondria in endothelial and smooth muscle cells. Treatment with colivelin ameliorated lung architecture, reduced organ neutrophil infiltration, and attenuated plasma levels of syndecan-1, tumor necrosis factor-α, macrophage inflammatory protein-1α and interleukin-10. These therapeutic effects of colivelin were associated with amelioration of glycocalyx density and mitochondrial structure in the aorta. At molecular analysis, colivelin treatment was associated with inhibition of the signal transducer and activator of transcription 3 and activation of the AMP-activated protein kinase in the aorta and lung. In long-term outcomes studies up to 7 days, co-treatment of colivelin with antimicrobial agents significantly reduced the disease severity score when compared to treatment with antibiotics alone. In conclusion, our data support that damage of the glycocalyx is an early pathogenetic event during sepsis and that colivelin may have therapeutic potential for the treatment of sepsis-associated endothelial dysfunction.

Association between inflammatory biomarkers and acute respiratory distress syndrome or acute lung injury risk : A systematic review and meta-analysis

Background

The relationship between acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) and levels of certain inflammatory factors remains controversial. The purpose of this meta-analysis was to summarize the available studies evaluating the association between levels of inflammatory factors and ARDS/ALI incidence.

Methods

We searched the PubMed, EmBase, and Cochrane databases for studies published up to July 2017. For each inflammatory factor, a random effects model was employed to pool results from different studies.

Results

We identified 63 studies that included 6243 patients in our meta-analysis. Overall, the results indicated that the levels of angiopoietin (ANG)-2 (standard mean difference, SMD: 1.34; P < 0.001), interleukin (IL)-1β (SMD: 0.92; P = 0.012), IL‑6 (SMD: 0.66; P = 0.005), and tumor necrosis factor (TNF)-α (SMD: 0.98; P = 0.001) were significantly higher in patients with ARDS/ALI than in unaffected individuals. No significant differences were observed between patients with ARDS/ALI and unaffected individuals in terms of the levels of IL‑8 (SMD: 0.61; P = 0.159), IL-10 (SMD: 1.10; P = 0.231), and plasminogen activator inhibitor (PAI)-1 (SMD: 0.70; P = 0.060).

Conclusions

ARDS/ALI is associated with a significantly elevated levels of ANG‑2, IL-1β, IL‑6, and TNF‑α, but not with IL‑8, IL-10, and PAI‑1 levels.

Supplementary Information

The online version of this article (10.1007/s00508-021-01971-3) contains supplementary material, which is available to authorized users.

Protective effect of dexmedetomidine in cecal ligation perforation-induced acute lung injury through HMGB1/RAGE pathway regulation and pyroptosis activation

Dexmedetomidine (DEX) has been reported to attenuate cecal ligation perforation (CLP)-stimulated acute lung injury (ALI) by downregulating HMGB1 and RAGE. This study aimed to further investigate the specific mechanisms of RAGE and its potential-related mechanisms of DEX on ALI models in vitro and in vivo. The in vitro and in vivo ALI models were established by lipopolysaccharide treatment in MLE-12 cells and CLP in mice, respectively. The effect of DEX on pathological alteration was investigated by HE staining. Thereafter, the myeloperoxidase (MPO) activity and inflammatory cytokine levels were respectively detected to assess the lung injury of mice using commercial kits. The expression levels of HMGB1, RAGE, NF-κB, and pyroptosis-related molecules were detected by RT-qPCR and Western blot. HE staining showed that lung injury, increased inflammatory cell infiltration, and lung permeability was found in the ALI mice, and DEX treatment significantly attenuated lung tissue damage induced by CLP. The MPO activity and inflammatory cytokines (TNF-α, IL-1β, and NLRP3) levels were also significantly reduced after DEX treatment compared with those in the ALI mice. Moreover, DEX activated the HMGB1/RAGE/NF-κB pathway and upregulated the pyroptosis-related proteins. However, the protective DEX effect was impaired by RAGE overexpression in ALI mice and MLE-12 cells. Additionally, DEX treatment significantly suppressed HMGB1 translocation from the nucleus region to the cytoplasm, and this effect was reversed by RAGE overexpression. These findings suggested that DEX may be a useful ALI treatment, and the protective effects on ALI mice may be through the inhibition of HMGB1/RAGE/NF-κB pathway and cell pyroptosis.

COVID-19: Lung-Centric Immunothrombosis

The respiratory tract is the major site of infection by SARS-CoV-2, the virus causing COVID-19. The pulmonary infection can lead to acute respiratory distress syndrome (ARDS) and ultimately, death. An excessive innate immune response plays a major role in the development of ARDS in COVID-19 patients. In this scenario, activation of lung epithelia and resident macrophages by the virus results in local cytokine production and recruitment of neutrophils. Activated neutrophils extrude a web of DNA-based cytoplasmic material containing antimicrobials referred to as neutrophil extracellular traps (NETs). While NETs are a defensive strategy against invading microbes, they can also serve as a nidus for accumulation of activated platelets and coagulation factors, forming thrombi. This immunothrombosis can result in occlusion of blood vessels leading to ischemic damage. Herein we address evidence in favor of a lung-centric immunothrombosis and suggest a lung-centric therapeutic approach to the ARDS of COVID-19.

GYY4137 alleviates sepsis-induced acute lung injury in mice by inhibiting the PDGFRβ/Akt/NF-κB/NLRP3 pathway

AIMS

GYY4137 [GYY, morpholin-4-ium-4-methoxyphenyl (morpholino) phosphinodithioate] is a novel and perfect hydrogen sulfide (H₂S) donor that is stable in vivo and in vitro. H₂S, along with CO and NO, has been recognized as the third physiological gas signaling molecule that plays an active role in fighting various lung infections. However, the mechanism by which GYY4137 affects cecal ligation and puncture (CLP)-induced acute lung injury (ALI) is not understood. This study aimed to investigate whether GYY4137 inhibits the activation of the pyrin domain-containing protein 3 (NLRP3) inflammasome by inhibiting the PDGFRβ/Akt/NF-κB pathway.

MAIN METHODS

The model of CLP-induced ALI was established in vivo. The mice were subsequently treated with GYY4137 (25 μg/g and 50 μg/g) to simulate the realistic conditions of pathogenesis. Western blotting and immunohistochemical staining were used to examine protein expression, hematoxylin and eosin staining was used for the histopathological analysis, and the levels of inflammatory factors were determined using enzyme-linked immunosorbent assays (ELISAs).

KEY FINDINGS

GYY4137 significantly increased the 7-day survival of mice with septic peritonitis and protected against CLP-induced ALI, including decreasing neutrophil infiltration, improving sepsis-induced lung histopathological changes, diminishing lung tissue damage, and attenuating the severity of lung injury in mice. The protective effect of GYY4137 was undoubtedly dose-dependent. We discovered that GYY4137 reduced the levels of the p-PDGFRβ, p-NF-κB, ASC, NLRP3, caspase-1, and p-Akt proteins in septic mouse lung tissue. Akt regulates the generation of proinflammatory cytokines in endotoxemia-associated ALI by enhancing the nuclear translocation of NF-κB.

SIGNIFICANCE

These results indicate a new molecular mechanism explaining the effect of GYY4137 on the treatment of CLP-induced ALI in mice.

The acute respiratory distress syndrome biomarker pipeline: crippling gaps between discovery and clinical utility

Recent innovations in translational research have ushered an exponential increase in the discovery of novel biomarkers, thereby elevating the hope for deeper insights into "personalized" medicine approaches to disease phenotyping and care. However, a critical gap exists between the fast pace of biomarker discovery and the successful translation to clinical use. This gap underscores the fundamental biomarker conundrum across various acute and chronic disorders: how does a biomarker address a specific unmet need? Additionally, the gap highlights the need to shift the paradigm from a focus on biomarker discovery to greater translational impact and the need for a more streamlined drug approval process. The unmet need for biomarkers in acute respiratory distress syndrome (ARDS) is for reliable and validated biomarkers that minimize heterogeneity and allow for stratification of subject selection for enrollment in clinical trials of tailored therapies. This unmet need is particularly highlighted by the ongoing SARS-CoV-2/COVID-19 pandemic. The unprecedented numbers of COVID-19-induced ARDS cases has strained health care systems across the world and exposed the need for biomarkers that would accelerate drug development and the successful phenotyping of COVID-19-infected patients at risk for development of ARDS and ARDS mortality. Accordingly, this review discusses the current state of ARDS biomarkers in the context of the drug development pipeline and highlight gaps between biomarker discovery and clinical implementation while proposing potential paths forward. We discuss potential ARDS biomarkers by category and by context of use, highlighting progress in the development continuum. We conclude by discussing challenges to successful translation of biomarker candidates to clinical impact and proposing possible novel strategies.

Bronchoalveolar lavage and plasma Antithrombin and cytokines in inhalation and burn injury: a pilot study

Systemic inflammatory response syndrome (SIRS) is initiated during the acute phase of thermal injury. The objective was to determine the SIRS impact on cytokine and Antithrombin (AT) levels in smoke inhalation and burn injury. This observational pilot study compared plasma and bronchoalveolar lavage fluid (BAL) cytokine and AT levels in the first six days post smoke inhalation and burn injury. Twenty-five patients, 14 with inhalation + burn injury > 10% total body surface area (TBSA) and 11 with inhalation injury and ≤ 10% TBSA participated. Human Th1/Th2 cytometric bead array kit from BD Biosciences Pharmingen determined cytokine levels; AT levels with Sigma Diagnostics and spectrophotometry. Results indicated no significant age difference between the two groups (42.1 ± 7.2) versus 49.6 ± 6.4 years. On admission, the inhalation group had 5.4 ± 3.9% TBSA compared to 35.0 ± 22.2% TBSA in the inhalation + burn group, P < 0.001. Comparing groups, AT plasma levels were significantly decreased (P = 0.025) and IL-2 levels significantly increased (P = 0.025) in the inhalation + burn group compared to the inhalation group; there was no significant difference in BAL AT or cytokine levels. Combined group plasma AT levels (65.41 ± 4.44%) were significantly increased compared to BAL AT levels (1.06 ± 0.71%), P < 0.001. In contrast, BAL TNF-α levels (35.61 ± 16.01 pg/ml) were significantly increased in relation to the plasma levels (4.68 ± 1.27 pg/ml), P = 0.02. On days 1-2, AT plasma levels were significantly decreased in the inhalation + burn group (41.01 ± 5.24%) compared to the inhalation group (81.02 ± 10.99%), P = 0.002. IL-6 plasma levels were higher in the inhalation + burn group compared to the inhalation group on admission, but both levels decreased by days 3-6. IL-6 BAL levels were elevated in both groups on days 1-2 and decreased by days 3-6. In the first six days of resuscitation, all plasma cytokines were increased in the two groups compared to controls. AT plasma and BAL levels were significantly reduced in both groups, contributing to the coagulopathy. Increased BAL TNF-α and IL-6 levels may have contributed to the pulmonary perturbations during the initial SIRS response in both groups.

An NMR based panorama of the heterogeneous biology of acute respiratory distress syndrome (ARDS) from the standpoint of metabolic biomarkers

Acute respiratory distress syndrome (ARDS), manifested by intricate etiology and pathophysiology, demands careful clinical surveillance due to its high mortality and imminent life support measures. NMR based metabolomics provides an approach for ARDS which culminates from a wide spectrum of illness thereby confounding early manifestation and prognosis predictors. ¹ H NMR with its manifold applications in critical disease settings can unravel the biomarker of ARDS thus holding potent implications by providing surrogate endpoints of clinical utility. NMR metabolomics which is the current apogee platform of omics trilogy is contributing towards the possible panacea of ARDS by subsequent validation of biomarker credential on larger datasets. In the present review, the physiological derangements that jeopardize the whole metabolic functioning in ARDS are exploited and the biomarkers involved in progression are addressed and substantiated. The following sections of the review also outline the clinical spectrum of ARDS from the standpoint of NMR based metabolomics which is an emerging element of systems biology. ARDS is the main premise of intensivists textbook, which has been thoroughly reviewed along with its incidence, progressive stages of severity, new proposed diagnostic definition, and the preventive measures and the current pitfalls of clinical management. The advent of new therapies, the need for biomarkers, the methodology and the contemporary promising approaches needed to improve survival and address heterogeneity have also been evaluated. The review has been stepwise illustrated with potent biometrics employed to selectively pool out differential metabolites as diagnostic markers and outcome predictors. The following sections have been drafted with an objective to better understand ARDS mechanisms with predictive and precise biomarkers detected so far on the basis of underlying physiological parameters having close proximity to diseased phenotype. The aim of this review is to stimulate interest in conducting more studies to help resolve the complex heterogeneity of ARDS with biomarkers of clinical utility and relevance.

Inhibition of miR-221 alleviates LPS-induced acute lung injury via inactivation of SOCS1/NF-κB signaling pathway

The role of inflammation response has been well documented in the development of acute lung injury (ALI). However, little is known about the functions of miRNAs in the regulation of inflammation in ALI. The aim of this study was to explore the effects of miRNAs in the regulation of inflammation in ALI and to elucidate the biomolecular mechanisms responsible for these effects. The expression profiles of miRNAs in lung tissues from lipopolysaccharide (LPS)-induced ALI mice model were analyzed using a microarray. It was observed that microRNA-221-3p (miR-221) was significantly increased in lung tissues in ALI mice. The inhibition of miR-221 attenuated lung injury including decreased lung W/D weight ratio and lung permeability and survival rates of ALI mice, as well as apoptosis, whereas its agomir-mediated upregulation exacerbated the lung injury. Concomitantly, miR-221 inhibition significantly reduced LPS-induced pulmonary inflammation, while LPS-induced pulmonary inflammation was aggravated by miR-221 upregulation. Of note, suppressor of cytokine signaling-1 (SOCS1), an effective suppressor of the NF-κB signaling pathway, was found to be a direct target of miR-221 in RAW264.7 cells. Overexpression of SOCS1 by pcDNA-SOCS1 plasmids markedly reversed the miR-221 inhibition-mediated inhibitory effects on inflammation and apoptosis in LPS-treated RAW264.7 cells. Finally, it was found that miR-221 inhibition suppressed LPS induced the activation of the NF-κB signaling pathway, as demonstrated by downregulation of phosphorylated-IκBα, p-p65 and upregulation of IκBα, whilst miR-221 overexpression had an opposite result in ALI mice. Our findings demonstrate that inhibition of miR-221 can alleviate LPS-induced inflammation via inactivation of SOCS1/NF-κB signaling pathway in ALI mice.

Inference of Cellular Immune Environments in Sputum and Peripheral Blood Associated with Acute Exacerbations of COPD

Introduction

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States, with high associated costs. Most of the cost burden results from acute exacerbations of COPD (AE-COPD), events associated with heightened symptoms and mortality. Cellular mechanisms underlying AE-COPD are poorly understood, likely because they arise from dysregulation of complex immune networks across multiple tissue compartments.

Methods

To gain systems-level insight into cellular environments relevant to exacerbation, we applied data-driven modeling approaches to measurements of immune factors (cytokines and flow cytometry) measured previously in two different human tissue environments (sputum and peripheral blood) during the stable and exacerbated state.

Results

Using partial least squares discriminant analysis, we identified a unique signature of cytokines in serum that differentiated stable and AE-COPD better than individual measurements. Furthermore, we found that models integrating data across tissue compartments (serum and sputum) trended towards being more accurate. The resulting paracrine signature defining AE-COPD events combined elevations of proteins associated with cell adhesion (sVCAM-1, sICAM-1) and increased levels of neutrophils and dendritic cells in blood with elevated chemoattractants (IP-10 and MCP-2) in sputum.

Conclusions

Our results supported a new hypothesis that AE-COPD is driven by immune cell trafficking into the lung, which requires expression of cell adhesion molecules and raised levels of innate immune cells in blood, with parallel upregulated expression of specific chemokines in pulmonary tissue. Overall, this work serves as a proof-of-concept for using data-driven modeling approaches to generate new insights into cellular processes involved in complex pulmonary diseases.

Neutrophils in the initiation and resolution of acute pulmonary inflammation: understanding biological function and therapeutic potential

Acute respiratory distress syndrome (ARDS) is the often fatal sequelae of a broad range of precipitating conditions. Despite decades of intensive research and clinical trials there remain no therapies in routine clinical practice that target the dysregulated and overwhelming inflammatory response that characterises ARDS. Neutrophils play a central role in the initiation, propagation and resolution of this complex inflammatory environment by migrating into the lung and executing a variety of pro-inflammatory functions. These include degranulation with liberation of bactericidal proteins, release of cytokines and reactive oxygen species as well as production of neutrophil extracellular traps. Although these functions are advantageous in clearing bacterial infection, the consequence of associated tissue damage, the contribution to worsening acute inflammation and prolonged neutrophil lifespan at sites of inflammation are deleterious. In this review, the importance of the neutrophil will be considered, together with discussion of recent advances in understanding neutrophil function and the factors that influence them throughout the phases of inflammation in ARDS. From a better understanding of neutrophils in this context, potential therapeutic targets are identified and discussed. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

GYY4137 attenuates LPS-induced acute lung injury via heme oxygenase-1 modulation

GYY4137, a slow-releasing hydrogen sulfide (H₂S) donor, has been reported to exert anti-inflammatory activity and protect against sepsis. Heme oxygenase-1 (HO-1) is an important anti-inflammatory heat shock protein and plays a similar effect on sepsis. This study investigated the role of GYY4137 in acute lung injury (ALI) via HO-1 regulation. Lung injury was assessed in mice challenged with intratracheal lipopolysaccharide (LPS) and the mechanism of anti-inflammatory effects of GYY4137 was investigated in mice and RAW264.7 cells. GYY4137 reduced the LPS-mediated pulmonary injury and neutrophil infiltration, and inhibited the LPS-induced production of proinflammatory cytokines, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Moreover, GYY4137 suppressed the LPS-evoked NF-κB activation in RAW264.7 cells. GYY4137, not time-expired GYY4137 significantly induced HO-1 expression compared with the LPS group. The beneficial effects of GYY4137 above were reversed by the HO-1 inhibitor tin protoporphyrin (SnPP). These results suggest an anti-inflammatory effect and a therapeutic role of GYY4137 in LPS-induced ALI via HO-1 regulation.

Prognosis value of Serum Cytokine levels among burn-induced ards patients

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Sodium butyrate alleviates LPS-induced acute lung injury in mice via inhibiting HMGB1 release

Sodium butyrate (SB) is a short chain 4-carbon fatty acid salt naturally exists in animal fats. Previous studies have proven that sodium butyrate has many beneficial functions such as anti-tumor and anti-inflammatory actions. In the current study we investigated the effect and possible mechanism of sodium butyrate in LPS-induced acute lung injury (ALI). ALI was induced by intratracheal administration of LPS (10 mg/kg) in male BALB/c mice. Sodium butyrate (500 mg/kg) was administered intraperitoneally 30 min prior to LPS exposure. We found that sodium butyrate significantly protected animals from LPS-induced ALI as evidenced by decreased the lung wet to dry weight ratio, total cells, neutrophils, macrophages, myeloperoxidase (MPO) activity, and lung histological damage compared to vehicle control. Sodium butyrate pretreatment markedly inhibited the production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Furthermore, sodium butyrate pretreatment dramatically suppressed HMGB1 release and NF-κ B activation. Together, these results suggest that sodium butyrate pretreatment protects mice from LPS-induced acute lung injury, possibly through the modulation of HMGB1 and inflammatory responses.

Effects of Ketamine on Icam-1 Expression during Lipopolysaccharide Induced Acute Lung Injury in Rats

Introduction

Intercellular adhesion molecule-1 (ICAM-1) serves very important roles in lung injury, and increases in ICAM-1 are associated with severity of lung injury. We intended to examine whether ketamine could have favourable effects on ICAM-1 expression in lipopolysaccharide (LPS)-induced acute lung injury in the rat.

Methods

The acute lung injury was induced by instilling LPS into the tracheas of 72 anaesthetised rats. The animals were divided into four groups including a sham group with intratracheal saline, an LPS group with intratracheal LPS and intraperitoneal saline, and two ketamine treatment groups with intratracheal LPS and treated with 1 mg/kg or 10 mg/kg doses of intraperitoneal ketamine hydrochloride. Half of the animals were sacrificed at three hours and the remaining animals were sacrificed at six hours. Real time PCR was performed on the lung tissues obtained. Concentration of the soluble ICAM-1 was measured in the bronchoalveolar lavage fluid. Expression of ICAM-1 was measured.

Results

The transcriptional activity of ICAM-1 mRNA increased 9.92 fold in the LPS group compared to the sham group but decreased by 84.1% and 83.3%, respectively, in the 1 and 10 mg/kg ketamine treatment groups. The concentration of soluble ICAM-1 in bronchoalveolar lavage fluid increased 2.23 fold in the LPS group compared to the sham group while decreasing by 75.0% and 74.5% respectively in the 1 mg/kg and 10 mg/kg ketamine treatment groups. The intensity of immunohistochemical staining for ICAM-1 was also decreased in both ketamine treatment groups.

Conclusion

Ketamine attenuates ICAM-1 expression during acute lung injury in rats. (Hong Kong j.emerg.med. 2011;18:397-405)

Isoliquiritigenin Activates Nuclear Factor Erythroid-2 Related Factor 2 to Suppress the NOD-Like Receptor Protein 3 Inflammasome and Inhibits the NF-κB Pathway in Macrophages and in Acute Lung Injury

Among the cellular response mechanisms, the nuclear factor erythroid-2 related factor 2 (Nrf2) pathway is considered a survival pathway that alleviates oxidative injury, while both the NOD-like receptor protein 3 (NLRP3) and NF-κB pathways are pro-inflammatory pathways that cause damage to cells. These pathways are implicated in the development and resolution of acute lung injury (ALI). Isoliquiritigenin (ISL), a flavonoid from the liquorice compound, is suggested to be a regulator of the above pathways, but the mechanisms of how the NLRP3/NF-κB pathway interacts with Nrf2 and its protective effects in ALI remain unknown. In the present study, ISL inhibited reactive oxygen species (ROS) generation and cytotoxicity induced by t-BHP and pro-inflammatory enzymes production induced by LPS in RAW 264.7 cells. Such cytoprotective effects coincided with the induction of AMP-activated protein kinase (AMPK)/Nrf2/antioxidant response element (ARE) signaling and the suppression of the NLRP3 and NF-κB pathways. Consistent with these findings, ISL treatment significantly alleviated lung injury in LPS-induced ALI mice, which was reflected by reductions in histopathological changes, pulmonary edema, and protein leakage. At the same time, the increased levels of inflammatory cell exudation and pro-inflammatory mediators, the enhanced production of ROS, myeloperoxidase, and malondialdehyde, and the depleted expression of GSH and superoxide dismutase induced by LPS were ameliorated by ISL. Furthermore, ISL notably activated AMPK/Nrf2/ARE signaling and inhibited LPS-induced NLRP3 and NF-κB activation in the lung. Moreover, although inhibition of the LPS-induced histopathological changes and ROS production were attenuated in Nrf2-deficient mice, the repression of the NLRP3 and NF-κB pathways by ISL was Nrf2-dependent and Nrf2-independent, respectively. In conclusion, our results are the first to highlight the beneficial role and relevant mechanisms of ISL in LPS-induced ALI and provide novel insight into its application.

Point-of-care washing of allogeneic red blood cells for the prevention of transfusion-related respiratory complications (WAR-PRC): a protocol for a multicenter randomised clinical trial in patients undergoing cardiac surgery

INTRODUCTION

The transfusion-related respiratory complications, transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO), are leading causes of transfusion-related morbidity and mortality. At present, there are no effective preventive strategies with red blood cell (RBC) transfusion. Although mechanisms remain incompletely defined, soluble biological response modifiers (BRMs) within the RBC storage solution may play an important role. Point-of-care (POC) washing of allogeneic RBCs may remove these BRMs, thereby mitigating their impact on post-transfusion respiratory complications.

METHODS AND ANALYSIS

This is a multicenter randomised clinical trial of standard allogeneic versus washed allogeneic RBC transfusion for adult patients undergoing cardiac surgery testing the hypothesis that POC RBC washing is feasible, safe, and efficacious and will reduce recipient immune and physiologic responses associated with transfusion-related respiratory complications. Relevant clinical outcomes will also be assessed. This investigation will enrol 170 patients at two hospitals in the USA. Simon's two-stage design will be used to assess the feasibility of POC RBC washing. The primary safety outcomes will be assessed using Wilcoxon Rank-Sum tests for continuous variables and Pearson chi-square test for categorical variables. Standard mixed modelling practices will be employed to test for changes in biomarkers of lung injury following transfusion. Linear regression will assess relationships between randomised group and post-transfusion physiologic measures.

ETHICS AND DISSEMINATION

Safety oversight will be conducted under the direction of an independent Data and Safety Monitoring Board (DSMB). Approval of the protocol was obtained by the DSMB as well as the institutional review boards at each institution prior to enrolling the first study participant. This study aims to provide important information regarding the feasibility of POC washing of allogeneic RBCs and its potential impact on ameliorating post-transfusion respiratory complications. Additionally, it will inform the feasibility and scientific merit of pursuing a more definitive phase II/III clinical trial.

REGISTRATION

ClinicalTrials.gov registration number is NCT02094118 (Pre-results).

The Prognostic Value of Soluble Intercellular Adhesion Molecule 1 Plasma Level in Children With Acute Lung Injury

OBJECTIVE

The objective of this study was to evaluate the prognostic significance of soluble intercellular adhesion molecule 1 (sICAM-1) measurement in plasma for the prediction of outcome of acute lung injury (ALI) in children that may allow early recognition of critical cases.

METHODS

The study was performed as a prospective, controlled cohort study involving 40 children with ALI and 30 healthy children. The plasma level of sICAM-1 was measured at days 1 and 3 of development of ALI for the patient group and measured only once for the control group. C-Reactive protein was measured in both groups on day 1 only.

RESULTS

There was significant increase in sICAM-1 in the patient group than in the control group ( P = .001*). The mortality rate reached 55% in children with ALI. The ceased group had significantly higher plasma sICAM-1 levels both at days 1 and 3 than the survived group ( P < .001*), and there was positive correlation between plasma sICAM-1 level and both duration of mechanical ventilation and the death rate, but more significant correlation was observed with plasma sICAM-1 levels at day 3 than day 1.

CONCLUSION

Plasma sICAM-1 level served as a good predictor biomarker for both mechanical ventilation duration and the mortality risk in children with ALI.

Soluble Adhesion Molecules During Ex Vivo Lung Perfusion Are Associated With Posttransplant Primary Graft Dysfunction

Ex vivo lung perfusion (EVLP) enables assessment of marginal donor lungs for transplantation. We aimed to discover biomarkers in EVLP perfusate that could predict development of primary graft dysfunction (PGD). From September 2008 to August 2013, 100 clinical EVLPs were performed. Eleven patients developed PGD grade 3 within 72 h after transplant. The non-PGD group consisted of 34 patients without PGD grade 3. Nonbilateral lung transplants or transplant after extracorporeal life support were excluded from analyses. Soluble intercellular adhesion molecule 1 (sICAM-1), soluble VCAM-1 (sVCAM-1), and soluble E selectin (sE-selectin) levels, as markers of endothelial activation, were measured in the perfusate of EVLP by enzyme-linked immunosorbent assay and were correlated with clinical outcome. Levels of sICAM-1 at 1 h and sVCAM-1 at 1 and 4 h were significantly higher in the PGD group compared with the non-PGD group. The sE selectin levels were not statistically different between the study groups. Higher levels of sVCAM-1 at 1 and 4 h were statistically significantly associated with PGD either alone or after adjustment for other PGD risk factors. These adhesion molecules may help identify donor lungs at higher risk of PGD during EVLP.

Artesunate Protects Against Sepsis-Induced Lung Injury Via Heme Oxygenase-1 Modulation

Artesunate, a derivative of artemisinin, has anti-inflammatory properties and exerts protective roles in sepsis. Heme oxygense-1 (HO-1) inhibits the inflammatory response through reduction of proinflammatory cytokines and leukocyte influx into tissues. The present study investigated the effects of artesunate on HO-1 and septic lung injury. Cecal ligation and puncture (CLP) was employed to induce septic lung injury. Mice pretreated with artesunate (AS) (15 mg/kg) exhibited decreased sepsis-induced mortality and lung injury and alleviated lung pathological changes and neutrophil infiltration. In addition, AS lowered the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the serum and bronchoalveolar lavage fluid (BALF) and inhibited cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase isoform (iNOS) expression and NF-κB activation in lung tissue. In addition, AS enhanced NF-E2-related factor-2 (Nrf2) activation and HO-1 expression and enzymatic activity in lung tissue. However, the protective effects of AS on sepsis-induced lung injury were eliminated by ZnPP IX, an HO-1 competitive inhibitor. Therefore, AS plays protective roles in septic lung injury related to the upregulation of HO-1. These findings suggest an effective and applicable treatment to sepsis-induced lung injury and provide new insights into the molecular mechanisms and actions of AS.

Aetiology, outcomes & predictors of mortality in acute respiratory distress syndrome from a tertiary care centre in north India

BACKGROUND & OBJECTIVES

Acute respiratory distress syndrome (ARDS) is a common disorder in critically ill patients and is associated with high mortality. There is a paucity of literature on this condition from developing countries. This prospective observational study was designed to find out the aetiology, outcomes and predictors of mortality in ARDS.

METHODS

Sixty four consecutive patients who satisfied American-European Consensus Conference (AECC) definition of ARDS from medical Intensive Care Unit (ICU) of a tertiary care centre in New Delhi, India, were enrolled in the study. Demographic, biochemical and ventilatory variables were recorded for each patient. Baseline measurements of serum interleukin (IL)-1β, IL-6, tumour necrosis factor-alpha (TNF-α), procalcitonin (PCT) and high sensitivity C-reactive protein (hsCRP) were performed.

RESULTS

Common causes of ARDS included pneumonia [44/64 (68.7%)], malaria [9/64 (14.1%)] and sepsis [8/64 (12.5%]. Eight of the 64 (12.5%) patients had ARDS due to viral pneumonia. The 28-day mortality was 36/64 (56.2%).Independent predictors of mortality included non-pulmonary organ failure, [Hazard ratio (HR) 7.65; 95% CI 0.98-59.7, P=0.05], Simplified Acute Physiology Score (SAPS-II) [HR 2.36; 95% CI 1.14-4.85, P=0.02] and peak pressure (P peak ) [HR 1.13; 95% CI 1.00-1.30, P = 0.04] at admission.

INTERPRETATION & CONCLUSIONS

Bacterial and viral pneumonia, malaria and tuberculosis resulted in ARDS in a considerable number of patients. Independent predictors of mortality included non-pulmonary organ failure, SAPS II score and P peak at baseline. Elevated levels of biomarkers such as TNF-α, PCT and hsCRP at admission might help in identifying patients at a higher risk of mortality.

Proteomic study of acute respiratory distress syndrome: current knowledge and implications for drug development

The acute respiratory distress syndrome (ARDS) is a common cause of acute respiratory failure, and is associated with substantial mortality and morbidity. Dozens of clinical trials targeting ARDS have failed, with no drug specifically targeting lung injury in widespread clinical use. Thus, the need for drug development in ARDS is great. Targeted proteomic studies in ARDS have identified many key pathways in the disease, including inflammation, epithelial injury, endothelial injury or activation, and disordered coagulation and repair. Recent studies reveal the potential for proteomic changes to identify novel subphenotypes of ARDS patients who may be most likely to respond to therapy and could thus be targeted for enrollment in clinical trials. Nontargeted studies of proteomics in ARDS are just beginning and have the potential to identify novel drug targets and key pathways in the disease. Proteomics will play an important role in phenotyping of patients and developing novel therapies for ARDS in the future.

Adhesion Molecules: Master Controllers of the Circulatory System

This manuscript will review our current understanding of cellular adhesion molecules (CAMs) relevant to the circulatory system, their physiological role in control of vascular homeostasis, innate and adaptive immune responses, and their importance in pathophysiological (disease) processes such as acute lung injury, atherosclerosis, and pulmonary hypertension. This is a complex and rapidly changing area of research that is incompletely understood. By design, we will begin with a brief overview of the structure and classification of the major groups of adhesion molecules and their physiological functions including cellular adhesion and signaling. The role of specific CAMs in the process of platelet aggregation and hemostasis and leukocyte adhesion and transendothelial migration will be reviewed as examples of the complex and cooperative interplay between CAMs during physiological and pathophysiological processes. The role of the endothelial glycocalyx and the glycobiology of this complex system related to inflammatory states such as sepsis will be reviewed. We will then focus on the role of adhesion molecules in the pathogenesis of specific disease processes involving the lungs and cardiovascular system. The potential of targeting adhesion molecules in the treatment of immune and inflammatory diseases will be highlighted in the relevant sections throughout the manuscript.

Soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1) Is Elevated in Bronchoalveolar Lavage Fluid of Patients with Acute Respiratory Distress Syndrome

INTRODUCTION

Pulmonary vascular endothelial activation has been implicated in acute respiratory distress syndrome (ARDS), yet little is known about the presence and role of endothelial activation markers in the alveolar space in ARDS. We hypothesized that endothelial activation biomarkers would be differentially expressed in bronchoalveolar lavage fluid from patients with ARDS compared with healthy volunteers, and that biomarker concentrations would be associated with ARDS severity.

METHODS

We performed a cross-sectional analysis of data from 26 intubated patients with ARDS undergoing evaluation for clinically suspected ventilator-associated pneumonia and five healthy volunteers. Patients underwent bronchoalveolar lavage a median of five days after intubation. Healthy volunteers also underwent bronchoalveolar lavage. Endothelial activation biomarkers (soluble vascular cell adhesion molecule-1 [sVCAM-1], soluble endothelial selectin [sESEL], angiopoietin-1 [Ang-1] and angiopoietin-2 [Ang-2]) were measured in bronchoalveolar lavage fluid. Clinically suspected ventilator-associated pneumonia was confirmed with microbiologic culture data.

RESULTS

Patients with ARDS had significantly higher median sVCAM-1 concentrations in the bronchoalveolar lavage fluid compared with healthy volunteers (985 vs 119 pg/mL, p = 0.03). Additionally, there was a trend toward greater bronchoalveolar lavage fluid sVCAM-1 concentrations among patients with moderate/severe compared to mild ARDS (1395 vs 209 pg/mL, p = 0.06). We did not detect significant differences in bronchoalveolar lavage fluid levels of sESEL, Ang-1 or Ang-2 between patients with ARDS and healthy volunteers. Median bronchoalveolar lavage fluid biomarker levels did not differ between patients with and without microbiologically-confirmed ventilator-associated pneumonia.

CONCLUSIONS

sVCAM-1 concentrations were significantly higher in the bronchoalveolar lavage fluid of patients with ARDS compared to healthy controls, and tended to be higher in moderate/severe ARDS compared to mild ARDS. Our findings add to the growing evidence supporting the concept that endothelial activation plays an important mechanistic role in the pathogenesis of ARDS. Further studies are necessary to characterize the role and/or clinical significance of sVCAM-1 and other endothelial activation markers present in the alveolar space in ARDS.

A Pathophysiologic Approach to Biomarkers in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is an acute-onset hypoxic condition with radiographic bilateral lung infiltration. It is characterized by an acute exudative phase combining diffuse alveolar damage and lung edema followed by a later fibroproliferative phase. Despite an improved understanding of ARDS pathobiology, our ability to predict the development of ARDS and risk-stratify patients with the disease remains limited. Biomarkers may help to identify patients at the highest risk of developing ARDS, assess response to therapy, predict outcome, and optimize enrollment in clinical trials. After a short description of ARDS pathobiology, here, we review the scientific evidence that supports the value of various ARDS biomarkers with regard to their major biological roles in ARDS-associated lung injury and/or repair. Ongoing research aims at identifying and characterizing novel biomarkers, in order to highlight relevant mechanistic explorations of lung injury and repair, and to ultimately develop innovative therapeutic approaches for ARDS patients. This review will focus on the pathophysiologic, diagnostic, and therapeutic implications of biomarkers in ARDS and on their utility to ultimately improve patient care.

Protective and immunomodulatory effect of flos Lonicerae japonicae by augmenting IL-10 expression in a murine model of acute lung inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Lonicerae japonicae has shown antibacterial, anti-inflammatory, antipyretic, antioxidant, antiviral, and protective effects in animal models of chronic obstructive pulmonary disease.

AIM OF THE STUDY

To investigate the effects of Flos L. japonicae (FLJ), a traditional Chinese medicinal herb, on acute lung inflammation induced by lipopolysaccharide (LPS), in vivo, using a murine model.

MATERIALS AND METHODS

Thirty 6-week-old female BALB/c mice were challenged with intratracheal LPS before treatment with FLJ or vehicle. FLJ was examined for its capacity to influence an LPS-induced increase in IL-10 and decrease in TNF-α, IL-1β and IL-6 as measured in murine bronchoalveolar lavage (BALF).

RESULTS

FLJ increased nuclear Sp1 binding activity thereby enhancing the expression of IL-10 and decreased nuclear NF-κB binding activities thereby inhibiting the expression of TNF-α, IL-1β and IL-6 in the lung. The up-regulation of Sp1 activity by FLJ was through incremental phosphorylation of ERK. By contrast, the down-regulation of NF-κB activity by FLJ was through suppression of the phosphorylation of IκB, p38, and JNK.

CONCLUSIONS

We demonstrated FLJ has protective activity against LPS-induced lung inflammatory cytokine release. Anti-inflammatory cytokine, IL-10, may prove beneficial in the treatment of endotoxin-associated lung inflammation.

Protective effects of protocatechuic acid on acute lung injury induced by lipopolysaccharide in mice via p38MAPK and NF-κB signal pathways

The study aims to investigate the effects of protocatechuic acid (PCA) separated from Chinese herbs, on acute lung injury (ALI) induced by lipopolysaccharide (LPS) in mice. The mouse model was induced by intraperitoneal injection of LPS at the dose of 5mg/kg body weight. Three doses of PCA (30, 15, 5 mg/kg) were administered to mice with intraperitoneal injection one hour prior to LPS exposure. Six hours later after LPS administration, the effect of PCA on ALI mice was assessed via histopathological examination by HE staining, inflammatory cytokine production by ELISA assay and RT-PCR, p38MAPK and NF-κB activation by Western blot analysis. We found that PCA administration significantly ameliorated lung histopathological changes and decreased protein concentration in the bronchoalveolar lavage fluid. Furthermore, the overproduction of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) was reduced by PCA. Additionally, PCA at the dose of 30 mg/kg could block the activation of p38MAPK and NF-κB signal pathways induced by LPS. In conclusion, our findings demonstrate that PCA possesses a protective effect on LPS-induced ALI in mice via suppression of p38MAPK and NF-κB signal pathways. Therefore, PCA may be useful in the therapy of lung inflammatory diseases, especially for ALI.

The Esophageal Pressure-Guided Ventilation 2 (EPVent2) trial protocol: a multicentre, randomised clinical trial of mechanical ventilation guided by transpulmonary pressure

INTRODUCTION

Optimal ventilator management for patients with acute respiratory distress syndrome (ARDS) remains uncertain. Lower tidal volume ventilation appears to be beneficial, but optimal management of positive end-expiratory pressure (PEEP) remains unclear. The Esophageal Pressure-Guided Ventilation 2 Trial (EPVent2) aims to examine the impact of mechanical ventilation directed at maintaining a positive transpulmonary pressure (PTP) in patients with moderate-to-severe ARDS.

METHODS AND ANALYSIS

EPVent2 is a multicentre, prospective, randomised, phase II clinical trial testing the hypothesis that the use of a PTP-guided ventilation strategy will lead to improvement in composite outcomes of mortality and time off the ventilator at 28 days as compared with a high-PEEP control. This study will enrol 200 study participants from 11 hospitals across North America. The trial will utilise a primary composite end point that incorporates death and days off the ventilator at 28 days to test the primary hypothesis that adjusting ventilator pressure to achieve positive PTP values will result in improved mortality and ventilator-free days.

ETHICS AND DISSEMINATION

Safety oversight will be under the direction of an independent Data and Safety Monitoring Board (DSMB). Approval of the protocol was obtained from the DSMB prior to enrolling the first study participant. Approvals of the protocol as well as informed consent documents were also obtained from the Institutional Review Board of each participating institution prior to enrolling study participants at each respective site. The findings of this investigation, as well as associated ancillary studies, will be disseminated in the form of oral and abstract presentations at major national and international medical specialty meetings. The primary objective and other significant findings will also be presented in manuscript form. All final, published manuscripts resulting from this protocol will be submitted to PubMed Central in accordance with the National Institute of Health Public Access Policy.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov under number NCT01681225.

Protective effects and mechanisms of mogroside V on LPS-induced acute lung injury in mice

CONTEXT

Mogroside V, a compound isolated from Momordica grosvenori Swingle, which belongs to the Cucurbitaceae, is a traditional Chinese medicine reported to have anti-inflammatory potential in murine macrophages and a murine ear edema model.

OBJECTIVE

To investigate the effects and mechanisms of action of this compound in a model of acute lung injury (ALI) induced by lipopolysaccharides (LPS).

MATERIALS AND METHODS

Female BALB/c mice were treated with commercial mogroside V (2.5, 5 and 10 mg/kg) for 1 h prior to intranasal injection of LPS (10 μg in 50 μl). After 12 h, airway inflammation in the ALI model was determined by the wet/dry weight (W/D) ratio, myeloperoxidase (MPO) activity of lung tissue, leukocyte recruitment and cytokine levels in the bronchoalveolar lavage fluid (BALF). Additionally, lung tissue was examined by histology and western blotting to investigate the changes in pathology and the signalling in the presence and absence of mogroside V.

RESULTS

Mogroside V at 5 and 10 mg/kg inhibited airway inflammation induced by LPS as measured by the decrease in the histological changes (44 and 67.3% reduction in lung injury score, respectively), a 28.9 and 55.3% reduction in lung MPO activity, and inflammatory cell counts, interleukin-1β (IL-1β, 382 and 280 pg/ml, respectively), IL-6 (378 and 232 pg/ml, respectively) and tumor necrosis factor-α (TNF-α, 12.5 and 7.8 ng/ml, respectively) levels in the BALF. Additionally, mogroside V treatment reduced the activation of cyclooxygenase 2 (COX-2), inducible NO synthase (iNOS), and the nuclear factor (NF)-κB.

DISCUSSIONS AND CONCLUSIONS

Together, these data suggest that mogroside V has the potential to protect against LPS-induced airway inflammation in a model of ALI.

Baicalein, an active component of Scutellaria baicalensis, protects against lipopolysaccharide-induced acute lung injury in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Baicalein (BE), a phenolic flavonoid extracted mainly from the root of Scutellaria baicalensis Georgi, a Chinese herb, is traditionally used in oriental medicine. Several studies have demonstrated that BE exerts many beneficial effects including anti-inflammatory and antioxidant activities. However, its effect on acute lung injury (ALI) and the molecular mechanisms involved remain unclear and warrant further investigation. The aim of the study is to investigate whether BE improves lipopolysaccharide (LPS, intratracheally, i.t.)-induced ALI in rats, and further study the underlying mechanisms of its activity.

MATERIAL AND METHODS

Rats were administrated with LPS (5mg/kg/body weight, i.t.) through a 24-gauge catheter to establish the ALI model. The effects of BE on the levels of pro-inflammatory cytokines, nitrite/nitrate in bronchoalveolar lavage fluid, and the expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and nuclear factor-kappa B (NF-κB) activation as well as the histopathological changes were evaluated.

RESULTS

Results showed that BE (20mg/kg, i.p.) treatment markedly attenuated LPS-induced lung edema, elevation of the levels of IL-1β, TNF-α, IL-6, CINC-3, and nitrite/nitrate in bronchoalveolar lavage fluid accompanied by a remarkable improvement of lung histopathological symptoms. The LPS-enhanced inflammatory cell infiltration and myeloperoxidase activity, O2(-) formation and the expression of inducible nitric oxide synthase and nitrotyrosin in lungs were all attenuated by BE. Notably, BE could augment Nrf2/HO-1 cascade, but inhibited NF-κB activation in LPS-instilled lungs that was strongly reversed by blocking HO-1 activity.

CONCLUSION

This study is the first to demonstrate that BE protects against LPS-induced ALI in rats. The underlying mechanisms may include inhibition of NF-κB-mediated inflammatory responses and upregulation of Nrf2/HO-1 pathway, which ultimately alleviates the pathological symptoms of ALI.

NLRP3 deletion protects from hyperoxia-induced acute lung injury

Inspiration of a high concentration of oxygen, a therapy for acute lung injury (ALI), could unexpectedly lead to reactive oxygen species (ROS) production and hyperoxia-induced acute lung injury (HALI). Nucleotide-binding domain and leucine-rich repeat PYD-containing protein 3 (NLRP3) senses the ROS, triggering inflammasome activation and interleukin-1β (IL-1β) production and secretion. However, the role of NLRP3 inflammasome in HALI is unclear. The main aim of this study is to determine the effect of NLRP3 gene deletion on inflammatory response and lung epithelial cell death. Wild-type (WT) and NLRP3(-/-) mice were exposed to 100% O2 for 48-72 h. Bronchoalveolar lavage fluid and lung tissues were examined for proinflammatory cytokine production and lung inflammation. Hyperoxia-induced lung pathological score was suppressed in NLRP3(-/-) mice compared with WT mice. Hyperoxia-induced recruitment of inflammatory cells and elevation of IL-1β, TNFα, macrophage inflammatory protein-2, and monocyte chemoattractant protein-1 were attenuated in NLRP3(-/-) mice. NLRP3 deletion decreased lung epithelial cell death and caspase-3 levels and a suppressed NF-κB levels compared with WT controls. Taken together, this research demonstrates for the first time that NLRP3-deficient mice have suppressed inflammatory response and blunted lung epithelial cell apoptosis to HALI.

Lung-derived mediators induce cytokine production in downstream organs via an NF-κB-dependent mechanism

In the setting of acute lung injury, levels of circulating inflammatory mediators have been correlated with adverse outcomes. Previous studies have demonstrated that injured, mechanically ventilated lungs represent the origin of the host inflammatory response; however, mechanisms which perpetuate systemic inflammation remain uncharacterized. We hypothesized that lung-derived mediators generated by mechanical ventilation (MV) are amplified by peripheral organs in a "feed forward" mechanism of systemic inflammation. Herein, lung-derived mediators were collected from 129X1/SVJ mice after 2 hours of MV while connected to the isolated perfused mouse lung model setup. Exposure of liver endothelial cells to lung-derived mediators resulted in a significant increase in G-CSF, IL-6, CXCL-1, CXCL-2, and MCP-1 production compared to noncirculated control perfusate media (P < 0.05). Furthermore, inhibition of the NF-κB pathway significantly mitigated this response. Changes in gene transcription were confirmed using qPCR for IL-6, CXCL-1, and CXCL-2. Additionally, liver tissue obtained from mice subjected to 2 hours of in vivo MV demonstrated significant increases in hepatic gene transcription of IL-6, CXCL-1, and CXCL-2 compared to nonventilated controls. Collectively, this data demonstrates that lung-derived mediators, generated in the setting of MV, are amplified by downstream organs in a feed forward mechanism of systemic inflammation.

Therapeutic effect of C-phycocyanin extracted from blue green algae in a rat model of acute lung injury induced by lipopolysaccharide

C-Phycocyanin (CPC), extracted from blue green algae, is a dietary nutritional supplement due to its several beneficial pharmacological effects. This study was conducted to evaluate whether CPC protects against lipopolysaccharide- (LPS-) induced acute lung injury (ALI) in rats. Rats were challenged with LPS (5 mg/kg body weight) intratracheally to induce ALI. After 3 h LPS instillation, rats were administrated with CPC (50 mg/kg body weight, i.p.) for another 3 h. Our results showed that posttreatment with CPC significantly inhibited LPS-induced elevation of protein concentration, nitrite/nitrate level, release of proinflammatory cytokines, the number of total polymorphonuclear cells in bronchoalveolar lavage fluid, and lung edema evidenced by decrease of lung wet/dry weight ratio accompanied by a remarkable improvement of lung histopathological alterations. Furthermore, CPC significantly attenuated LPS-induced myeloperoxidase activity, O2 (-) formation, expression of inducible nitric oxide synthase, and cyclooxygenase-2 as well as nuclear factor-kappa B (NF- κ B) activation in lungs. Additionally, CPC significantly downregulated proapoptotic proteins such as caspase-3 and Bax, but upregulated antiapoptotic proteins such as Bcl-2 and Bcl-XL in lungs exposed to LPS. These findings indicate that CPC could be potentially useful for treatment of LPS-related ALI by inhibiting inflammatory responses and apoptosis in lung tissues.

The protective effect of alpha-lipoic Acid in lipopolysaccharide-induced acute lung injury is mediated by heme oxygenase-1

Alpha-lipoic acid (ALA), occurring naturally in human food, is known to possess antioxidative and anti-inflammatory activities. Induction of heme oxygenase-1 (HO-1) has been reported to exhibit a therapeutic effect in several inflammatory diseases. The aim of study was to test the hypothesis that the protection of ALA against lipopolysaccharide-(LPS-) induced acute lung injury (ALI) is mediated by HO-1. Pre- or posttreatment with ALA significantly inhibited LPS-induced histological alterations of ALI, lung tissue edema, and production of proinflammatory cytokine, cytokine inducible neutrophil chemoattractant-3, and nitrite/nitrate in bronchoalveolar lavage fluid. In addition, the inflammatory responses including elevation of superoxide formation, myeloperoxidase activity, polymorphonuclear neutrophils infiltration, nitrotyrosine, inducible nitric oxide synthase expression and nuclear factor-kappa B (NF-κB) activation in lung tissues of LPS-instilled rats were also markedly reduced by ALA. Interestingly, treatment with ALA significantly increased nuclear factor-erythroid 2-related factor 2 (Nrf2) activation and HO-1 expression in lungs of ALI. However, blocking HO-1 activity by tin protoporphyrin IX (SnPP), an HO-1 inhibitor, markedly abolished these beneficial effects of ALA in LPS-induced ALI. These results suggest that the protection mechanism of ALA may be through HO-1 induction and in turn suppressing NF-κB-mediated inflammatory responses.

Shikonin attenuates lipopolysaccharide-induced acute lung injury in mice

BACKGROUND

Shikonin, a natural naphthoquinone pigment extracted from the root of Lithospermum erythrorhizon, has shown a variety of pharmacologic properties including anti-inflammatory effect. In the present study, we analyzed the role of shikonin in acute lung injury induced by lipopolysaccharide (LPS) in mice.

MATERIALS AND METHODS

Sixty male BALB/C mice were randomly allocated into six groups (n = 10, each): control group, shikonin group (50 mg/kg), LPS group, and three different doses (12.5, 25, and 50 mg/kg) for shikonin-treated groups. Shikonin or vehicle was given with an intragastric administration 1 h before an intratracheal instillation of LPS (5 mg/kg). The severity of pulmonary injury was evaluated 6 h after LPS challenge.

RESULTS

Shikonin pretreatment significantly attenuated LPS-induced pulmonary histopathologic changes, alveolar hemorrhage, and neutrophil infiltration. The lung wet-to-dry weight ratios, as the index of pulmonary edema, were markedly decreased by shikonin pretreatment. Moreover, shikonin decreased the productions of the proinflammatory cytokines including tumor necrosis factor alpha and interleukin 1β and the concentration of total proteins in the bronchoalveolar lavage fluid. Shikonin pretreatment also reduced the concentrations of myeloperoxidase and nitric oxide in lung tissues. In addition, shikonin pretreatment significantly suppressed LPS-induced activation of cyclooxygenase 2 and inducible nitric oxide synthase and the nuclear factor κB DNA-binding activity in lung tissues.

CONCLUSIONS

This study indicates that shikonin may have a protective effect against LPS-induced acute lung injury, and the potential mechanism of this action may attribute partly to the inhibition of inducible nitric oxide synthase and cyclooxygenase 2 expression by downregulating nuclear factor κB activation.

Pentoxifylline reduces tumor necrosis factor-α and HIV-induced vascular endothelial activation

Untreated HIV infection is associated with endothelial dysfunction and subsequent cardiovascular disease, likely due to both direct effects of the virus and to indirect effects of systemic inflammation on the vasculature. We have recently shown that treatment with the antiinflammatory agent pentoxifylline (PTX) improved in vivo endothelial function and reduced circulating levels of the inflammatory markers vascular cell adhesion molecule-1 (VCAM-1) and interferon-gamma-induced protein (IP-10) in HIV-infected patients. To delineate the mechanisms underlying this therapeutic effect, we tested whether clinically relevant concentrations of PTX suppress VCAM-1 or IP-10 release in cultivated human lung microvascular endothelial cells. Indeed, we found that tumor necrosis factor (TNF)-α-induced VCAM-1 was reduced with concentrations of PTX in the low nanomolar range, comparable to plasma levels in PTX-treated groups. We also investigated the effect of HIV proteins and found that HIV transactivator of transcription (HIV-Tat) and HIV-envelope-derived recombinant gp120 enhanced TNF-α-induced VCAM-1 gene expression in lung microvascular and coronary macrovascular endothelial cells, respectively. In addition, PTX and a NF-κB-specific inhibitor reduced this enhanced VCAM-1 gene induction in microvascular and macrovascular endothelial cells. These results provide novel insights in how the antiinflammatory agent PTX can directly reduce HIV-associated proinflammatory endothelial activation, which may underlie vascular dysfunction and coronary vascular diseases.

Biomarkers in acute lung injury

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) result in high permeability pulmonary edema causing hypoxic respiratory failure with high morbidity and mortality. As the population ages, the incidence of ALI is expected to rise. Over the last decade, several studies have identified biomarkers in plasma and bronchoalveolar lavage fluid providing important insights into the mechanisms involved in the pathophysiology of ALI. Several biomarkers have been validated in subjects from the large, multicenter ARDS clinical trials network. Despite these studies, no single or group of biomarkers has made it into routine clinical practice. New high throughput "omics" techniques promise improved understanding of the biologic processes in the pathogenesis in ALI and possibly new biomarkers that predict disease and outcomes. In this article, we review the current knowledge on biomarkers in ALI.