Pharmacotherapy of acute lung injury and the acute respiratory distress syndrome

A Narrative Review on the Administration of Inhaled Prostaglandins in Critically Ill Adult Patients With Acute Respiratory Distress Syndrome

OBJECTIVE

To describe the effect of inhaled prostaglandins on both oxygenation and mortality in critically ill patients with acute respiratory distress syndrome (ARDS), with a focus on safety and efficacy in coronavirus disease 2019 (COVID-19)-associated ARDS and non-COVID-19 ARDS.

DATA SOURCES

A literature search of MEDLINE was performed using the following search terms: inhaled prostaglandins, inhaled epoprostenol, inhaled nitric oxide, ARDS, critically ill. All abstracts were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Relevant English-language reports and studies conducted in humans between 1980 and June 2023 were considered.

DATA SYNTHESIS

Data regarding inhaled prostaglandins and their effect on oxygenation are limited but show a benefit in patients who respond to therapy, and data pertaining to their effect on mortality is scarce. Concerns exist regarding the formulation of inhaled epoprostenol (iEPO) utilized in addition to modes of medication delivery; however, the limited data surrounding their use have shown a reasonable safety profile. Other avenues and beneficial effects may exist with inhaled prostaglandins, such as use in COVID-19-associated ARDS or non-COVID-19 ARDS patients undergoing noninvasive mechanical ventilation or during patient transport.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

The use of inhaled prostaglandins can be considered in critically ill patients with COVID-19-associated ARDS or non-COVID-19 ARDS who are experiencing difficulties with oxygenation refractory to nonpharmacologic strategies.

CONCLUSIONS

The use of iEPO and other inhaled prostaglandins requires further investigation to fully elucidate their effects on clinical outcomes, but it appears these medications may have a potential benefit in COVID-19-associated ARDS and non-COVID-19 ARDS patients with refractory hypoxemia but with little effect on mortality.

Synthetic steroid of 5α-Androst-3β,5α,6β-Triol alleviates acute lung injury via inhibiting inflammation and oxidative stress

Acute lung injury (ALI) is a severe and potentially fatal respiratory condition with limited treatment options. The pathological evolution of ALI is driven by persistent inflammation, destruction of the pulmonary vascular barrier and oxidative stress. Evidence from prior investigations has identified 5α-androst-3β,5α,6β-Triol (TRIOL), a synthetic analogue of the naturally occurring neuroprotective compound cholestane-3β,5α,6β-triol, possesses notable anti-inflammatory and antioxidative properties. However, the precise effects of TRIOL on alleviating lung injury along with the mechanisms, have remained largely unexplored. Here, TRIOL exhibited pronounced inhibitory actions on lipopolysaccharide (LPS)-induced inflammation and oxidative stress damage in both lung epithelial and endothelial cells. This protective effect is achieved by its ability to mitigate oxidative stress and restrain the inflammatory cascade orchestrated by nuclear factor-kappa B (NF-κB), thereby preserving the integrity of the pulmonary epithelial barrier. We further validated that TRIOL can attenuate LPS-induced lung injury in rats and mice by reducing inflammatory cell infiltration and improving pulmonary edema. Furthermore, TRIOL decreased the pro-inflammatory factors and increased of anti-inflammatory factors induced by LPS. In conclusion, our study presents TRIOL as a promising novel candidate for the treatment of ALI.

Targeted Delivery of the Pan-Inflammasome Inhibitor MM01 as an Alternative Approach to Acute Lung Injury Therapy

Acute lung injury (ALI) is a severe pulmonary disorder responsible for high percentage of mortality and morbidity in intensive care unit patients. Current treatments are ineffective, so the development of efficient and specific therapies is an unmet medical need. The activation of NLPR3 inflammasome during ALI produces the release of proinflammatory factors and pyroptosis, a proinflammatory form of cell death that contributes to lung damage spreading. Herein, it is demonstrated that modulating inflammasome activation through inhibition of ASC oligomerization by the recently described MM01 compound can be an alternative pharmacotherapy against ALI. Besides, the added efficacy of using a drug delivery nanosystem designed to target the inflamed lungs is determined. The MM01 drug is incorporated into mesoporous silica nanoparticles capped with a peptide (TNFR-MM01-MSNs) to target tumor necrosis factor receptor-1 (TNFR-1) to proinflammatory macrophages. The prepared nanoparticles can deliver the cargo in a controlled manner after the preferential uptake by proinflammatory macrophages and exhibit anti-inflammatory activity. Finally, the therapeutic effect of MM01 free or nanoparticulated to inhibit inflammatory response and lung injury is successfully demonstrated in lipopolysaccharide-mouse model of ALI. The results suggest the potential of pan-inflammasome inhibitors as candidates for ALI therapy and the use of nanoparticles for targeted lung delivery.

Efficacy of CU06-1004 via regulation of inflammation and endothelial permeability in LPS-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is a life-threatening condition that fundamentally results from inflammation and edema in the lung. There are no effective treatments available for clinical use. Previously, we found that as a leakage blocker CU06-1004 prevents endothelial barrier disruption and enhances endothelial cell survival under inflammatory conditions. In this study, we aimed to elucidate the effect of CU06-1004 in terms of prevention of inflammation and endothelial dysfunction in an ALI mouse model.

METHODS

An ALI model was established that included intraperitoneal administration of LPS. Following LPS administration, survival rates and lung wet/dry ratios were assessed. Histological analysis was performed using hematoxylin and eosin staining. Scanning electron microscopy was used to examine alveolar and capillary morphology. Cytokines such as IL-1β, IL-6, and TNF-α were analyzed using an ELISA assay of bronchoalveolar lavage fluid (BALF) and serum. Neutrophil infiltration was observed in BALF using Wright-Giemsa staining, and myeloperoxidase (MPO) activity was assessed. Pulmonary vascular leakage was confirmed using Evans-blue dye, and the expression of junctional proteins was evaluated using immunofluorescent staining. Expression of adhesion molecules was observed using immunofluorescence staining. NF-κB activation was determined using immunohistochemistry and western blot analysis.

RESULTS

Survival rates and pulmonary edema were ameliorated with CU06-1004 treatment. Administration of CU06-1004 normalized histopathological changes induced by LPS, and alveolar-capillary wall thickening was reduced. Compared with the LPS-challenged group, after CU06-1004 treatment, the infiltration of immune cells was decreased in the BALF, and MPO activity in lung tissue was reduced. Similarly, in the CU06-1004 treatment group, pro-inflammatory cytokines were significantly inhibited in both BALF and serum. Evans-blue leakage was reduced, and the expression of junctional proteins was recovered in the CU06-1004 group. Adhesion molecules were downregulated and NF-κB activation was inhibited after CU06-1004 treatment.

CONCLUSIONS

These results suggested that CU06-1004 had a therapeutic effect against LPS-induced ALI via alleviation of the inflammatory response and protection of vascular integrity.

Pharmacologic therapies of ARDS: From natural herb to nanomedicine

Acute respiratory distress syndrome (ARDS) is a common critical illness in respiratory care units with a huge public health burden. Despite tremendous advances in the prevention and treatment of ARDS, it remains the main cause of intensive care unit (ICU) management, and the mortality rate of ARDS remains unacceptably high. The poor performance of ARDS is closely related to its heterogeneous clinical syndrome caused by complicated pathophysiology. Based on the different pathophysiology phases, drugs, protective mechanical ventilation, conservative fluid therapy, and other treatment have been developed to serve as the ARDS therapeutic methods. In recent years, there has been a rapid development in nanomedicine, in which nanoparticles as drug delivery vehicles have been extensively studied in the treatment of ARDS. This study provides an overview of pharmacologic therapies for ARDS, including conventional drugs, natural medicine therapy, and nanomedicine. Particularly, we discuss the unique mechanism and strength of nanomedicine which may provide great promises in treating ARDS in the future.

CXC Chemokines in the Pathogenesis of Pulmonary Disease and Pharmacological Relevance

Chemokines and their receptors play important roles in the pathophysiology of many diseases by regulating the cellular migration of major inflammatory and immune players. The CXC motif chemokine subfamily is the second largest family, and it is further subdivided into ELR motif CXC (ELR+) and non-ELR motif (ELR-) CXC chemokines, which are effective chemoattractants for neutrophils and lymphocytes/monocytes, respectively. These chemokines and their receptors are expected to have a significant impact on a wide range of lung diseases, many of which have inflammatory or immunological underpinnings. As a result, manipulations of this subfamily of chemokines and their receptors using small molecular agents and other means have been explored for potential therapeutic benefit in the setting of several lung pathologies. Furthermore, encouraging preclinical data has necessitated the progression of a few of these drugs into clinical trials in order to make the most effective use of interventions in the development of viable targeted therapeutics. The current review presents the understanding of the roles of CXC ligands (CXCLs) and their cognate receptors (CXCRs) in the pathogenesis of several lung diseases such as allergic rhinitis, COPD, lung fibrosis, lung cancer, pneumonia, and tuberculosis. The potential therapeutic benefits of pharmacological or other CXCL/CXCR axis manipulations are also discussed.

STING inhibitor ameliorates LPS-induced ALI by preventing vascular endothelial cells-mediated immune cells chemotaxis and adhesion

Acute lung injury (ALI) is a common and devastating clinical disorder featured by excessive inflammatory responses. Stimulator of interferon genes (STING) is an indispensable molecule for regulating inflammation and immune response in multiple diseases, but the role of STING in the ALI pathogenesis is not well elucidated. In this study, we explored the molecular mechanisms of STING in regulating lipopolysaccharide (LPS)-induced lung injury. Mice were pretreated with a STING inhibitor C-176 (15, 30 mg/kg, i.p.) before LPS inhalation to induce ALI. We showed that LPS inhalation significantly increased STING expression in the lung tissues, whereas C-176 pretreatment dose-dependently suppressed the expression of STING, decreased the production of inflammatory cytokines including TNF-α, IL-6, IL-12, and IL-1β, and restrained the expression of chemokines and adhesion molecule vascular cell adhesion protein-1 (VCAM-1) in the lung tissues. Consistently, in vitro experiments conducted in TNF-α-stimulated HMEC-1cells (common and classic vascular endothelial cells) revealed that human STING inhibitor H-151 or STING siRNA downregulated the expression levels of adhesion molecule and chemokines in HMEC-1cells, accompanied by decreased adhesive ability and chemotaxis of immunocytes upon TNF-α stimulation. We further revealed that STING inhibitor H-151 or STING knockdown significantly decreased the phosphorylation of transcription factor STAT1, which subsequently influenced its binding to chemokine CCL2 and adhesive molecule VCAM-1 gene promoter. Collectively, STING inhibitor can alleviate LPS-induced ALI in mice by preventing vascular endothelial cells-mediated immune cell chemotaxis and adhesion, suggesting that STING may be a promising therapeutic target for the treatment of ALI.

New Insights into the Role of the Complement System in Human Viral Diseases

The complement system (CS) is part of the human immune system, consisting of more than 30 proteins that play a vital role in the protection against various pathogens and diseases, including viral diseases. Activated via three pathways, the classical pathway (CP), the lectin pathway (LP), and the alternative pathway (AP), the complement system leads to the formation of a membrane attack complex (MAC) that disrupts the membrane of target cells, leading to cell lysis and death. Due to the increasing number of reports on its role in viral diseases, which may have implications for research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), this review aims to highlight significant progress in understanding and defining the role of the complement system in four groups of diseases of viral etiology: (1) respiratory diseases; (2) acute liver failure (ALF); (3) disseminated intravascular coagulation (DIC); and (4) vector-borne diseases (VBDs). Some of these diseases already present a serious global health problem, while others are a matter of concern and require the collaboration of relevant national services and scientists with the World Health Organization (WHO) to avoid their spread.

Mesenchymal Stem Cell-Derived Exosome Therapy of Microbial Diseases: From Bench to Bed

Microbial diseases are a global health threat, leading to tremendous casualties and economic losses. The strategy to treat microbial diseases falls into two broad categories: pathogen-directed therapy (PDT) and host-directed therapy (HDT). As the typical PDT, antibiotics or antiviral drugs directly attack bacteria or viruses through discerning specific molecules. However, drug abuse could result in antimicrobial resistance and increase infectious disease morbidity. Recently, the exosome therapy, as a HDT, has attracted extensive attentions for its potential in limiting infectious complications and targeted drug delivery. Mesenchymal stem cell-derived exosomes (MSC-Exos) are the most broadly investigated. In this review, we mainly focus on the development and recent advances of the application of MSC-Exos on microbial diseases. The review starts with the difficulties and current strategies in antimicrobial treatments, followed by a comprehensive overview of exosomes in aspect of isolation, identification, contents, and applications. Then, the underlying mechanisms of the MSC-Exo therapy in microbial diseases are discussed in depth, mainly including immunomodulation, repression of excessive inflammation, and promotion of tissue regeneration. In addition, we highlight the latest progress in the clinical translation of the MSC-Exo therapy, by summarizing related clinical trials, routes of administration, and exosome modifications. This review will provide fundamental insights and future perspectives on MSC-Exo therapy in microbial diseases from bench to bedside.

N-Acetylcysteine in Mechanically Ventilated Rats with Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome: The Effect of Intravenous Dose on Oxidative Damage and Inflammation

Treatment of acute respiratory distress syndrome (ARDS) is challenging due to its multifactorial aetiology. The benefit of antioxidant therapy was not consistently demonstrated by previous studies. We evaluated the effect of two different doses of intravenous (i.v.) N-acetylcysteine (NAC) on oxidative stress, inflammation and lung functions in the animal model of severe LPS-induced lung injury requiring mechanical ventilation. Adult Wistar rats with LPS (500 μg/kg; 2.2 mL/kg) were treated with i.v. NAC 10 mg/kg (NAC10) or 20 mg/kg (NAC20). Controls received saline. Lung functions, lung oedema, total white blood cell (WBC) count and neutrophils count in blood and bronchoalveolar lavage fluid, and tissue damage in homogenized lung were evaluated. NAC significantly improved ventilatory parameters and oxygenation, reduced lung oedema, WBC migration and alleviated oxidative stress and inflammation. NAC20 in comparison to NAC10 was more effective in reduction of oxidative damage of lipids and proteins, and inflammation almost to the baseline. In conclusion, LPS-instilled and mechanically ventilated rats may be a suitable model of ARDS to test the treatment effects at organ, systemic, cellular and molecular levels. The results together with literary data support the potential of NAC in ARDS.

Potential therapeutic interventions of plant-derived isoflavones against acute lung injury

Acute lung injury (ALI) is a life-threatening syndrome that possibly leads to high morbidity and mortality as no therapy exists. Several natural ingredients with negligible adverse effects have recently been investigated to possibly inhibit the inflammatory pathways associated with ALI at the molecular level. Isoflavones, as phytoestrogenic compounds, are naturally occurring bioactive compounds that represent the most abundant category of plant polyphenols (Leguminosae family). A broad range of therapeutic activities of isoflavones, including antioxidants, chemopreventive, anti-inflammatory, antiallergic and antibacterial potentials, have been extensively documented in the literature. Our review exclusively focuses on the possible anti-inflammatory, antioxidant role of botanicals'-derived isoflavones against ALI and their immunomodulatory effect in experimentally induced ALI. Despite the limited scope covering their molecular mechanisms, isoflavones substantially contributed to protecting from ALI via inhibiting toll-like receptor 4 (TLR4)/Myd88/NF-κB pathway and subsequent cytokines, chemokines, and adherent proteins. Nonetheless, future research is suggested to fill the gap in elucidating the protective roles of isoflavones to alleviate ALI concerning antioxidant potentials, inhibition of the inflammatory pathways, and associated molecular mechanisms.

Mesoporous silica nanoparticles for pulmonary drug delivery

Over the last years, respiratory diseases represent a clinical concern, being included among the leading causes of death in the world due to the lack of effective lung therapies, mainly ascribed to the pulmonary barriers affecting the delivery of drugs to the lungs. In this way, nanomedicine has arisen as a promising approach to overcome the limitations of current therapies for pulmonary diseases. The use of nanoparticles allows enhancing drug bioavailability at the target site while minimizing undesired side effects. Despite different approaches have been developed for pulmonary delivery of drugs, including the use of polymers, lipid-based nanoparticles, and inorganic nanoparticles, more efforts are required to achieve effective pulmonary drug delivery. This review provides an overview of the clinical challenges in main lung diseases, as well as highlighted the role of nanomedicine in achieving efficient pulmonary drug delivery. Drug delivery into the lungs is a complex process limited by the anatomical, physiological and immunological barriers of the respiratory system. We discuss how nanomedicine can be useful to overcome these pulmonary barriers and give insights for the rational design of future nanoparticles for enhancing lung treatments. We also attempt herein to display more in detail the potential of mesoporous silica nanoparticles (MSNs) as promising nanocarrier for pulmonary drug delivery by providing a comprehensive overview of their application in lung delivery to date while discussing the use of these particles for the treatment of respiratory diseases.

Targeted-lung delivery of dexamethasone using gated mesoporous silica nanoparticles. A new therapeutic approach for acute lung injury treatment

Acute lung injury (ALI) is a critical inflammatory syndrome, characterized by increased diffuse inflammation and severe lung damage, which represents a clinical concern due to the high morbidity and mortality in critical patients. In last years, there has been a need to develop more effective treatments for ALI, and targeted drug delivery to inflamed lungs has become an attractive research field. Here, we present a nanodevice based on mesoporous silica nanoparticles loaded with dexamethasone (a glucocorticoid extensively used for ALI treatment) and capped with a peptide that targets the TNFR1 receptor expressed in pro-inflammatory macrophages (TNFR-Dex-MSNs) and avoids cargo leakage. TNFR-Dex-MSNs nanoparticles are preferentially internalized by pro-inflammatory macrophages, which overexpressed the TNFR1 receptor, with the subsequent cargo release upon the enzymatic hydrolysis of the capping peptide in lysosomes. Moreover, TNFR-Dex-MSNs are able to reduce the levels of TNF-α and IL-1β cytokines in activated pro-inflammatory M1 macrophages. The anti-inflammatory effect of TNFR-Dex-MSNs is also tested in an in vivo ALI mice model. The administered nanodevice (intravenously by tail vein injection) accumulated in the injured lungs and the controlled dexamethasone release reduces markedly the inflammatory response (TNF-α IL-6 and IL-1β levels). The attenuation in lung damage, after treatment with TNFR-Dex-MSNs, is also confirmed by histopathological studies. Besides, the targeted-lung dexamethasone delivery results in a decrease of dexamethasone derived side-effects, suggesting that targeted nanoparticles can be used for therapy in ALI and could help to overcome the clinical limitations of current treatments.

Cisatracurium attenuates LPS-induced modulation of MMP3 and junctional protein expression in human microvascular endothelial cells

Acute respiratory distress syndrome (ARDS) is a life-threatening form of acute lung injury (ALI) associated with hypoxemic lung damage and inflammation. Matrix metalloproteinase protein-3 (MMP3 or Stromelysin-1) is known to promote vascular injury in ALI/ARDS. Cisatracurium, a nicotinic neuromuscular blocker, is used in ARDS patients to decrease mechanical ventilator dyssynchrony, increase oxygenation, and improve mortality. However, the magnitude and the underlying mechanisms of these potential benefits of cisatracurium remains unclear. We investigated the effect of cisatracurium on lipopolysaccharide-induced MMP3 expression in human microvascular endothelial cells. In our results, cisatracurium treatment significantly decreased LPS-induced MMP3 expression and increased expression of cell junction proteins such as vascular endothelial cadherin (VE-cadherin) and claudin-5.

The Effect of Exogenous Surfactant on Moderate and Severe Stages of COVID-19 Induced ARDS: the Pilot Study of a Clinical Trial

COVID-19 pandemic has created a global health challenge. Many pharmaceuticals have been repurposed as potential treatments, though many have not been promising. Due to the inflammatory and destructive effects of the virus on alveolar cells, the effect of exogenous surfactant was assessed as a potential treatment of lung dysfunction in COVID-19 patients. In this pilot study of the clinical trial, 49 patients aged 35-80 years with COVID-19 admitted in ICU entered the study (22 patients intubated and 23 had face masks; 4 patients in the control arm). The treatment arm patients received two consecutive doses of surfactant. P/F ratio (based on serial blood gas analyses before and 12 hours after 2 doses of surfactant) and also, clinical outcomes were assessed.in COVID-19 adult patients, surfactant significantly improved pulmonary P/F ratio both in intubated and face mask COVID-19 patients (increasing from 119.2 ± 51.7 to 179.4 ± 115.5). The rate of extubation was much better than similar country-wide studies. Surfactant significantly alleviates the respiratory status in moderate to severe COVID-19 ARDS with two consecutive 100 mg doses of surfactant (with 6 hours' interval) though previous studies have been controversial, regarding the effect of surfactant in general forms of ARDS. Higher doses might have better effects, mandating more trials.

MicroRNA-145 plays a role in mitochondrial dysfunction in alveolar epithelial cells in lipopolysaccharide-induced acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) causes substantial mortalities. Alveolar epithelium is one of the main sites of cell injuries in ARDS. As an important kind of microRNAs (miRNAs), microRNA-145 (miR-145) has been studied in various diseases, while its role in ARDS has not been investigated.

METHODS

Lipopolysaccharide (LPS) was intratracheally instilled to establish a rat ARDS model. Cytokines from bronchoalveolar lavage fluid (BALF) were measured using rat tumor necrosis factor-α and interleukin-6 enzyme-linked immunosorbent assay kits (R&D Systems), and the pathological structures were evaluated using hematoxylin and eosin (H&E) staining and transmission electron microscope; the lung miR-145 messenger RNA (mRNA) was detected using quantitative polymerase chain reaction. Bioinformatics focused on the target genes and possible pathways of gene regulation.

RESULTS

A rat model of LPS-induced ARDS was successfully established. The miR-145 was down-regulated in the LPS-induced ARDS lung, and mitochondrial dysfunction was observed in alveolar epithelial cells, most obviously at 72 hours after LPS. TargetScan and miRDB databases were used to predict the target genes of miR-145. A total of 428 overlapping genes were identified, seven genes were associated with mitochondrial function, and Ogt, Camk2d, Slc8a3, and Slc25a25 were verified. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched in the mitogen-activated protein kinase (MAPK) signaling pathway, and Gene Ontology (GO) biological process was mainly enriched in signal transduction and transcription regulation.

CONCLUSIONS

The miR-145 is down-regulated in LPS-induced ARDS, and affects its downstream genes targeting mitochondrial functions.

Lisofylline mitigates cardiac inflammation in a mouse model of obesity through improving insulin secretion and activating cardiac AMPK signaling pathway

Obesity has emerged as a leading cause of death in the last few decades, mainly due to associated cardiovascular diseases. Obesity, inflammation, and insulin resistance are strongly interlinked. Lisofylline (LSF), an anti-inflammatory agent, demonstrated protection against type 1 diabetes, as well as reduced obesity-induced insulin resistance and adipose tissue inflammation. However, its role in mitigating cardiac inflammation associated with obesity is not well studied. Mice were divided into 4 groups; the first group was fed regular chow diet, the second was fed regular chow diet and treated with LSF, the third was fed high fat diet (HFD), and the fourth was fed HFD and treated with LSF. Cardiac inflammation was interrogated via expression levels of TNF α, interleukins 6 and 10, phosphorylated STAT4 and lipoxygenases 12 and 12/15. Apoptosis and expression of the survival gene, AMPK, were also evaluated. We observed that LSF alleviated obesity-induced cardiac injury indirectly by improving both pancreatic β-cell function and insulin sensitivity, as well as, directly via upregulation of cardiac AMPK expression and downregulation of cardiac inflammation and apoptosis. LSF may represent an effective therapy targeting obesity-induced metabolic and cardiovascular complications.

Effect of different dosages of dexamethasone therapy on lung function and inflammation in an early phase of acute respiratory distress syndrome model

Inflammation associated with acute respiratory distress syndrome (ARDS) can damage the alveolar epithelium and surfactant and worsen the respiratory failure. Glucocorticoids (GC) appear to be a rational therapeutic approach, but the effect is still unclear, especially for early administration and low-dose. In this study we compared two low doses of dexamethasone in early phase of surfactant-depleted model of acute respiratory distress syndrome (ARDS). In the study, lung-lavaged New Zealand rabbits with respiratory failure (PaO(2)<26.7 kPa in FiO(2) 1.0) were treated with intravenous dexamethasone (DEX): 0.5 mg/kg (DEX-0.5) and 1.0 mg/kg (DEX-1.0), or were untreated (ARDS). Animals without ARDS served as controls. Respiratory parameters, lung edema, leukocyte shifts, markers of inflammation and oxidative damage in the plasma and lung were evaluated. Both doses of DEX improved the lung function vs. untreated animals. DEX-1.0 had faster onset with significant improvement in gas exchange and ventilation efficiency vs. DEX-0.5. DEX-1.0 showed a trend to reduce lung neutrophils, local oxidative damage, and levels of TNFalpha, IL-6, IL-8 more effectively than DEX-0.5 vs. ARDS group. Both dosages of dexamethasone significantly improved the lung function and suppressed inflammation in early phase ARDS, while some additional enhancement was observed for higher dose (1 mg/kg) of DEX.

COVID-19-Associated dyslipidemia: Implications for mechanism of impaired resolution and novel therapeutic approaches

The current coronavirus disease 2019 (COVID‐19) pandemic presents a global challenge for managing acutely ill patients and complications from viral infection. Systemic inflammation accompanied by a “cytokine storm,” hemostasis alterations and severe vasculitis have all been reported to occur with COVID‐19, and emerging evidence suggests that dysregulation of lipid transport may contribute to some of these complications. Here, we aim to summarize the current understanding of the potential mechanisms related to COVID‐19 dyslipidemia and propose possible adjunctive type therapeutic approaches that modulate lipids and lipoproteins. Specifically, we hypothesize that changes in the quantity and composition of high‐density lipoprotein (HDL) that occurs with COVID‐19 can significantly decrease the anti‐inflammatory and anti‐oxidative functions of HDL and could contribute to pulmonary inflammation. Furthermore, we propose that lipoproteins with oxidized phospholipids and fatty acids could lead to virus‐associated organ damage via overactivation of innate immune scavenger receptors. Restoring lipoprotein function with ApoA‐I raising agents or blocking relevant scavenger receptors with neutralizing antibodies could, therefore, be of value in the treatment of COVID‐19. Finally, we discuss the role of omega‐3 fatty acids transported by lipoproteins in generating specialized proresolving mediators and how together with anti‐inflammatory drugs, they could decrease inflammation and thrombotic complications associated with COVID‐19.

Treatment of Paraquat-Induced Lung Injury With an Anti-C5a Antibody: Potential Clinical Application

OBJECTIVES

Complement activation product C5a plays a critical role in systemic inflammatory response syndrome induced by viruses, bacteria, and toxic agents including paraquat poisoning. This study is to explore the efficiency of anti-C5a-based intervention on systemic inflammatory responses induced by paraquat poisoning.

DESIGN

Study of cynomolgus macaque model and plasma from paraquat-poisoning patients.

SETTING

Laboratory investigation.

SUBJECTS

Cynomolgus macaque (n = 12) and samples of plasma from patients (n = 16).

INTERVENTIONS

The neutralizing antihuman C5a antibody (IFX-1) was administered to investigate the new treatment strategy for paraquat-induced systemic inflammatory responses in cynomolgus macaque model. In addition, C5a activation in plasma of paraquat patients was blocked by IFX-1 to investigate the blockade role of anti-C5a antibody in activation of inflammatory cells.

MEASUREMENTS AND MAIN RESULTS

Dysregulated complement activation and the subsequent cytokine storm were found in patients with acute lung injury and in a primate model of paraquat poisoning. Targeted inhibition of C5a by IFX-1 led to marked alleviation of systemic inflammatory responses and multiple organ damage in the primate model. In addition, blockade of C5a activity in plasma from patients completely inhibited activation of CD11b on blood granulocytes from normal donors, suggesting that IFX-1 may alleviate the excessive activation of inflammatory responses and have clinical utility for patients with acute lung injury.

CONCLUSIONS

Anti-C5a antibodies such as IFX-1 may be used as effective therapeutics for treatment of those suffering from systemic inflammatory responses induced by chemical poisoning like paraquat.

Ulinastatin ameliorates LPS‑induced pulmonary inflammation and injury by blocking the MAPK/NF‑κB signaling pathways in rats

Ulinastatin, a urinary trypsin inhibitor (UTI) is commonly used to treat patients with acute inflammatory disease. However, the underlying mechanisms of its anti‑inflammatory effect in acute lung injury (ALI) are not fully understood. The present study aimed to investigate the protective effect of UTI and explore its potential mechanisms by using a rat model of lipopolysaccharide (LPS)‑induced ALI. Rats were treated with 5 mg/kg LPS by intratracheal instillation. The histological changes in LPS‑induced ALI was evaluated using hematoxylin and eosin staining and the myeloperoxidase (MPO) activity was determined using ELISA. The wet/dry ratio (W/D ratio) of the lungs was used to assess the severity of pulmonary edema and Evans blue dye was used to evaluate the severity of lung vascular leakage. The results demonstrated that LPS administration induced histological changes and significantly increased the lung W/D ratio, MPO activity and Evans blue dye extravasation compared with the control group. However, treatment with UTI attenuated LPS‑induced ALI in rats by modifying histological changes and reducing the lung W/D ratio, MPO activity and Evans blue dye extravasation. In addition, LPS induced the secretion of numerous pro‑inflammatory cytokines in bronchoalveolar lavage fluid (BALF), including tumor necrosis factor‑α, interleukin (IL)‑6, IL‑1β and interferon‑γ; however, these cytokines were strongly reduced following treatment with UTI. In addition, UTI was able to reduce cellular counts in BALF, including neutrophils and leukocytes. Western blotting demonstrated that UTI significantly blocked the LPS‑stimulated MAPK and NF‑κB signaling pathways. The results of the present study indicated that UTI could exert an anti‑inflammatory effect on LPS‑induced ALI by inhibiting the MAPK and NF‑κB signaling pathways, which suggested that UTI may be considered as an effective drug in the treatment of ALI.

Protective Effects of Chymostatin on Paraquat-Induced Acute Lung Injury in Mice

This study aims to evaluate the role of chymostatin in paraquat-induced acute lung injury. Institute of Cancer Research mice were randomly distributed into the NS, DMSO, chymostatin, paraquat or chymostatin treatment groups. Six mice from each group were intraperitoneally injected with chloral hydrate at 0, 1, 2, 4, 8, 12, 24 and 48 h after treatment administration. Blood samples were collected through cardiac puncture. Lung tissues were stained with haematoxylin and eosin for the observation of lung histology. The degree of pulmonary oedema was determined on the basis of lung wet-to-dry ratio (W/D). The serum activity of cathepsin G was determined through substrate fluorescence assay. The serum levels of endothelial cell-specific molecule-1 (endocan), tumour necrosis factor-a (TNF-a), interleukin-1β (IL-1β), IL-6 and high-mobility group box protein 1 (HMGB1) were determined through enzyme-linked immunosorbent assay. The expression levels of endocan and nuclear NF-κBp65 in the lung were quantified through Western blot. Chymostatin alleviated the pathological changes associated with acute alveolitis in mice; decreased the lung W/D ratio, the activity of cathepsin G and the serum concentrations of TNF-a, IL-1β, IL-6 and HMGB1; and increased the serum concentration of endocan. Western blot results revealed that chymostatin up-regulated endocan expression and down-regulated nuclear NF-κBp65 expression in the lung. Chymostatin reversed the inflammatory effects of paraquat-induced lung injury by inhibiting cathepsin G activity to up-regulate endocan expression and indirectly inhibit NF-κBp65 activity.

Isolation, culture, and characterization of chicken lung-derived mesenchymal stem cells

Using lung tissues separated from 12-day-old chicken embryos, we attempted to obtain a novel population of stem cells, namely, chicken lung-derived mesenchymal stem cells (LMSCs), which exhibit spindle-like morphology. The results of colony-forming assay and population doubling assay demonstrated that LMSCs had enormous colony-forming, self-renewal, and proliferative potential. When appropriately induced, LMSCs could differentiate into osteoblasts, adypocytes, chondrocytes, and neurons; in other words, LMSCs had cross-embryonic layer differentiation potential under corresponding induction conditions. Aside from colony-forming, self-renewal, and multilineage differentiation capabilities, LMSCs were characterized by specific cell phenotypes. The results of immunohistochemistry and flow cytometry demonstrated that LMSCs consistently expressed OCT-4 - a specific gene marker expressed in pluripotent stem cells - and markers associated with MSCs such as CD29, CD73, CD90, and CD105. However, LMSCs lacked hematopoietic cell surface molecules such as CD34 and CD45. Primary LMSCs could be subcultured to passage 24 at most in vitro and karyotype analysis demonstrated that LMSCs possessed genomic stability. These unique characteristics were consistent with the characteristics of MSCs, which had been isolated from other tissues. This provides a foundation for LMSCs as a promising avenue for cellular transplantation therapy, regenerative medicine, and tissue engineering.

Anti-inflammatory effects and mechanism of the total flavonoids from Artemisia scoparia Waldst. et kit. in vitro and in vivo

Artemisia scoparia Waldst. et Kit. is traditionally used for the treatment of jaundice urinary retention, itching wet sores, infectious icteric hepatitis and influenza in Uighur medicine. This study aimed to further illuminate the anti-inflammatory effects and mechanism of the total flavonoids (ASTF) from Artemisia scoparia Waldst. et Kit. In vitro, RAW 264.7 cells were pretreated with ASTF 1 h before stimulation with LPS (1 μg/mL) for 24 h. Then, the concentrations of NO, PGE₂, TNF-α, IL-6 and MCP-1 in the medium were determined. Intracellular oxidative stress was detected using DCFH-DA. Immunofluorescent analysis, western blot and qRT-PCR were carried out to illuminate the mechanism of anti-inflammatory effects of ASTF. In vivo, mice were given an intragastric administration of ASTF 1 h before an intranasal administration of LPS. After 24 h, bronchoalveolar lavage fluid (BALF) was collected to measure the number of total cells, macrophage and neutrophils. The levels of TNF-α and IL-6 in BALF were quantified by ELISA kits. Lung specimens were isolated for histopathological examinations and lung wet-to-dry weight (W/D) ratio. We found that ASTF significantly inhibited the production of NO, PGE₂, TNF-α, IL-6, MCP-1 and reactive oxygen species (ROS) in LPS-stimulated RAW 264.7 cells. ASTF can obviously inhibit the degredation of IκBa and inhibit the nucleus translocations of p-NF-κB p65, p-ERK1/2 and p-p38 in RAW 264.7 cells stimulated by LPS. ASTF also markedly decreased the protein and mRNA expression of TNF-α and IL-6 in a dose-dependent manner. When pretreated with ASTF, alveolar hemorrhage and neutrophil infiltration, as well as pulmonary histopathologic changes, were substantially suppressed in lung tissues in the murine acute lung injury model. The lung wet-to-dry weight (W/D) ratio was strongly decreased. These results suggested that ASTF showed important anti-inflammatory activity and might provide protective effects against LPS-induced ALI. The anti-inflammatory effect of ASTF might attribute to its suppression of NF-κB and MAPK signaling pathway.

Effects of indole alkaloids from leaf of Alstonia scholaris on post-infectious cough in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Leaf of Alstonia scholaris (L.) R. Br. (Apocynaceae), a wide used ethic-medicine in many Asia and Africa counties, has also been recorded as the common traditional Chinese medicine for treatment of illnesses in respiratory system by Dai people.

AIM OF THE STUDY

To provide experimental data of clinical adaption of total indole alkaloids (TA) from leaf of A. scholaris for treating post-infectious cough in phase II clinical trial.

MATERIALS AND METHODS

To model post-infectious cough, all animals except control group were instilled intra-tracheal with lipopolysaccharide (LPS) (80 μg/50 µL/mouse), followed by subsequent exposure to cigarette smoke (CS) for 30 min per day for a total of 30 days. Mice were orally given TA at dose of 10, 25, 50 mg/kg, and four main alkaloids (Sch: scholaricine, Epi: 19-epischolaricine, Val: vallesamine, Pic: picrinine) once daily. Cellular infiltration was assessed in the broncho-alveolar lavage fluid (BALF). Expression of interleukin-6 (IL-6) and C-reactive protein (CRP) in the serum was determined, the superoxide dismutase (SOD) activity as well as malondialdehyde (MDA) content in the serum and homogenate were examined. Finally, histopathological examination in the lungs was assessed by H. E. staining.

RESULTS

After administration of TA and four major alkaloids respectively, the symptoms of cough in mice were obviously attenuated. Total white blood cells (WBC) and neutrophils (NEU) amounts in BALF were reduced obviously and the pathological damage of lung was also attenuated. There was also significant reduction in IL-6, CRP, MDA and a marked improvement in SOD.

CONCLUSIONS

The efficacy of indole alkaloids against post-infectious cough (PIC) was shown in the down-regulation of inflammatory cells, cytokines, and the balance of antioxidants. What's more, the pharmacological effects of TA were better than single indole alkaloid, which might be related to the synergic effect of four major alkaloids.

C5L2, the Second C5a Anaphylatoxin Receptor, Suppresses LPS-Induced Acute Lung Injury

LPS-induced lung injury in the mouse is one of the most robust experimental models used for studies of acute lung injury (ALI) and acute respiratory distress syndrome in humans. Prior clinical and experimental studies support an important role for complement activation, particularly production of C5a, in the pathophysiology of human ALI/acute respiratory distress syndrome. In the mouse model, however, the precise role of C5a and its receptors is unclear. C5L2, an enigmatic second receptor for C5a, has been characterized, and results have generated substantial debate regarding its in vivo function. Our previous work with human neutrophils revealed a unique role for C5L2 in negatively modulating C5a-C5a receptor (C5aR)-mediated cellular activation, in which antibody-mediated blockade of C5L2 resulted in augmented C5a-C5aR responses. Here, we demonstrate that C5L2^-/- mice (BALB/c background) administered intranasal LPS exhibit significantly more airway edema and hemorrhage than do wild-type animals. Bronchoalveolar lavage fluid and lung homogenates have significantly more neutrophils and myeloperoxidase activity, as well as proinflammatory cytokines and chemokines. When a blocking antibody against the C5aR was administered before LPS administration, the increased neutrophilic infiltration and cytokine levels were reversed. Thus, our data show not only that C5a contributes significantly to LPS-induced ALI in the mouse, but also that C5L2 plays an important antiinflammatory role in this model through actions resulting at least in part from negative modulation of C5a receptor activation.

Identification and validation of distinct biological phenotypes in patients with acute respiratory distress syndrome by cluster analysis

RATIONALE

We hypothesised that patients with acute respiratory distress syndrome (ARDS) can be clustered based on concentrations of plasma biomarkers and that the thereby identified biological phenotypes are associated with mortality.

METHODS

Consecutive patients with ARDS were included in this prospective observational cohort study. Cluster analysis of 20 biomarkers of inflammation, coagulation and endothelial activation provided the phenotypes in a training cohort, not taking any outcome data into account. Logistic regression with backward selection was used to select the most predictive biomarkers, and these predicted phenotypes were validated in a separate cohort. Multivariable logistic regression was used to quantify the independent association with mortality.

RESULTS

Two phenotypes were identified in 454 patients, which we named 'uninflamed' (N=218) and 'reactive' (N=236). A selection of four biomarkers (interleukin-6, interferon gamma, angiopoietin 1/2 and plasminogen activator inhibitor-1) could be used to accurately predict the phenotype in the training cohort (area under the receiver operating characteristics curve: 0.98, 95% CI 0.97 to 0.99). Mortality rates were 15.6% and 36.4% (p<0.001) in the training cohort and 13.6% and 37.5% (p<0.001) in the validation cohort (N=207). The 'reactive phenotype' was independent from confounders associated with intensive care unit mortality (training cohort: OR 1.13, 95% CI 1.04 to 1.23; validation cohort: OR 1.18, 95% CI 1.06 to 1.31).

CONCLUSIONS

Patients with ARDS can be clustered into two biological phenotypes, with different mortality rates. Four biomarkers can be used to predict the phenotype with high accuracy. The phenotypes were very similar to those found in cohorts derived from randomised controlled trials, and these results may improve patient selection for future clinical trials targeting host response in patients with ARDS.

Plasma membrane wounding and repair in pulmonary diseases

Various pathophysiological conditions such as surfactant dysfunction, mechanical ventilation, inflammation, pathogen products, environmental exposures, and gastric acid aspiration stress lung cells, and the compromise of plasma membranes occurs as a result. The mechanisms necessary for cells to repair plasma membrane defects have been extensively investigated in the last two decades, and some of these key repair mechanisms are also shown to occur following lung cell injury. Because it was theorized that lung wounding and repair are involved in the pathogenesis of acute respiratory distress syndrome (ARDS) and idiopathic pulmonary fibrosis (IPF), in this review, we summarized the experimental evidence of lung cell injury in these two devastating syndromes and discuss relevant genetic, physical, and biological injury mechanisms, as well as mechanisms used by lung cells for cell survival and membrane repair. Finally, we discuss relevant signaling pathways that may be activated by chronic or repeated lung cell injury as an extension of our cell injury and repair focus in this review. We hope that a holistic view of injurious stimuli relevant for ARDS and IPF could lead to updated experimental models. In addition, parallel discussion of membrane repair mechanisms in lung cells and injury-activated signaling pathways would encourage research to bridge gaps in current knowledge. Indeed, deep understanding of lung cell wounding and repair, and discovery of relevant repair moieties for lung cells, should inspire the development of new therapies that are likely preventive and broadly effective for targeting injurious pulmonary diseases.

Comparison of inhaled milrinone, nitric oxide and prostacyclin in acute respiratory distress syndrome

AIM

To evaluate the safety and efficacy of inhaled milrinone in acute respiratory distress syndrome (ARDS).

METHODS

Open-label prospective cross-over pilot study where fifteen adult patients with hypoxemic failure meeting standard ARDS criteria and monitored with a pulmonary artery catheter were recruited in an academic 24-bed medico-surgical intensive care unit. Random sequential administration of iNO (20 ppm) or nebulized epoprostenol (10 μg/mL) was done in all patients. Thereafter, inhaled milrinone (1 mg/mL) alone followed by inhaled milrinone in association with inhaled nitric oxide (iNO) was administered. A jet nebulization device synchronized with the mechanical ventilation was use to administrate the epoprostenol and the milrinone. Hemodynamic measurements and partial pressure of arterial oxygen (PaO₂) were recorded before and after each inhaled therapy administration.

RESULTS

The majority of ARDS were of pulmonary cause (n = 13) and pneumonia (n = 7) was the leading underlying initial disease. Other pulmonary causes of ARDS were: Post cardiopulmonary bypass (n = 2), smoke inhalation injury (n = 1), thoracic trauma and pulmonary contusions (n = 2) and aspiration (n = 1). Two patients had an extra pulmonary cause of ARDS: A polytrauma patient and an intra-abdominal abscess Inhaled nitric oxide, epoprostenol, inhaled milrinone and the combination of inhaled milrinone and iNO had no impact on systemic hemodynamics. No significant adverse events related to study medications were observed. The median increase of PaO₂ from baseline was 8.8 mmHg [interquartile range (IQR) = 16.3], 6.0 mmHg (IQR = 18.4), 6 mmHg (IQR = 15.8) and 9.2 mmHg (IQR = 20.2) respectively with iNO, epoprostenol, inhaled milrinone, and iNO added to milrinone. Only iNO and the combination of inhaled milrinone and iNO had a statistically significant effect on PaO₂.

CONCLUSION

When comparing the effects of inhaled NO, milrinone and epoprostenol, only NO significantly improved oxygenation. Inhaled milrinone appeared safe but failed to improve oxygenation in ARDS.

Lung protection by inhalation of exogenous solubilized extracellular matrix

Decellularized extracellular matrix (ECM) contains complex tissue-specific components that work in concert to promote tissue repair and constructive remodeling and has been used experimentally and clinically to accelerate epithelial wound repair, leading us to hypothesize that lung-derived ECM could mitigate acute lung injury. To explore the therapeutic potential of ECM for noninvasive delivery to the lung, we decellularized and solubilized porcine lung ECM, then characterized the composition, concentration, particle size and stability of the preparation. The ECM preparation at 3.2 mg/mL with average particle size <3 μm was tested in vitro on human A549 lung epithelial cells exposed to 95% O2 for 24 hours, and in vivo by tracheal instillation or nebulization into the lungs of rats exposed intermittently or continuously to 90% O2 for a cumulative 72 hours. Our results showed that the preparation was enriched in collagen, reduced in glycosaminoglycans, and contained various bioactive molecules. Particle size was concentration-dependent. Compared to the respective controls treated with cell culture medium in vitro or saline in vivo, ECM inhalation normalized cell survival and alveolar morphology, and reduced hyperoxia-induced apoptosis and oxidative damage. This proof-of-concept study established the methodology, feasibility and therapeutic potential of exogenous solubilized ECM for pulmonary cytoprotection, possibly as an adjunct or potentiator of conventional therapy.

Regulation of S1P receptors and sphingosine kinases expression in acute pulmonary endothelial cell injury

Background

Acute lung injury and acute respiratory distress syndrome (ALI/ARDS) is a severe clinical syndrome with mortality rate as high as 30–40%. There is no treatment yet to improve pulmonary endothelial barrier function in patients with severe pulmonary edema. Developing therapies to protect endothelial barrier integrity and stabilizing gas exchange is getting more and more attention. Sphingosine-1-phosphate (S1P) is able to enhance the resistance of endothelial cell barrier. S1P at physiological concentrations plays an important role in maintaining endothelial barrier function. Proliferation, regeneration and anti-inflammatory activity that mesenchymal stem cells (MSCs) exhibit make it possible to regulate the homeostatic control of S1P.

Methods

By building a pulmonary endothelial cell model of acute injury, we investigated the regulation of S1P receptors and sphingosine kinases expression by MSCs during the treatment of acute lung injury using RT-PCR, and investigated the HPAECs Micro-electronics impedance using Real Time Cellular Analysis.

Results

It was found that the down-regulation of TNF-α expression was more significant when MSC was used in combination with S1P. The combination effection mainly worked on S1PR2, S1PR3 and SphK2. The results show that when MSCs were used in combination with S1P, the selectivity of S1P receptors was increased and the homeostatic control of S1P concentration was improved through regulation of expression of S1P metabolic enzymes.

Discussions

The study found that, as a potential treatment, MSCs could work on multiple S1P related genes simultaneously. When it was used in combination with S1P, the expression regulation result of related genes was not simply the superposition of each other, but more significant outcome was obtained. This study establishes the experimental basis for further exploring the efficacy of improving endothelial barrier function in acute lung injury, using MSCs in combination with S1P and their possible synergistic mechanism.

Curcumin inhibits paraquat induced lung inflammation and fibrosis by extracellular matrix modifications in mouse model

OBJECTIVE

Paraquat (PQ), a potent herbicide can cause severe toxicity. We report here that fibroproliferation phase of acute lung injury (ALI) is initiated much earlier (within 48 h) after PQ intoxication than previously reported (after 2 weeks) and we aimed to study the protective effects of intranasal curcumin as new therapeutic strategy in mouse model.

METHODS

Mice (Park's strain) were divided into five experimental groups (I) control, received only saline (0.9 % NaCl) (II) PQ, mice intoxicated with PQ (50 mg/kg, i.p., single dose); (III) curcumin, treated with curcumin (5 mg/kg, i.n) an hour before PQ administration; (IV)Veh, DMSO (equal volume to curcumin) given an hour before PQ exposure; (V) DEXA, mice treated with dexamethasone (1 mg/kg, i.p) before an hour of PQ intoxication. After 48 h of the PQ exposure, all mice were sacrificed and samples were analyzed.

RESULTS

Pretreatment with intranasal curcumin (5 mg/kg) could modify the PQ-intoxication (50 mg/kg, i.p) induced structural remodeling of lung parenchyma at an early phase of acute lung injury. Significant increase in inflammatory cell count, reactive oxygen species and hydroxyproline levels were decreased after curcumin pretreatment (all p < 0.05). Histological examination and zymography results were also found consistent.

CONCLUSION

Our results show that curcumin pretreatment decreased the expression of alpha smooth muscle actin (α-SMA), matrix metalloproteinases-9 (MMP-9) and changed the expression of tissue inhibitors of metalloproteinase (TIMP-1) after PQ intoxication. Single toxic dose of PQ has initiated fibroproliferation within 48 h and intranasal curcumin may prove as new therapeutic strategy for PQ induced ALI and fibroproliferation.

The Src family tyrosine kinases src and yes have differential effects on inflammation-induced apoptosis in human pulmonary microvascular endothelial cells

Endothelial cells are essential for normal lung function: they sense and respond to circulating factors and hemodynamic alterations. In inflammatory lung diseases such as acute respiratory distress syndrome, endothelial cell apoptosis is an inciting event in pathogenesis and a prominent pathological feature. Endothelial cell apoptosis is mediated by circulating inflammatory factors, which bind to receptors on the cell surface, activating signal transduction pathways, leading to caspase-3-mediated apoptosis. We hypothesized that yes and src have differential effects on caspase-3 activation in human pulmonary microvascular endothelial cells (hPMVEC) due to differential downstream signaling effects. To test this hypothesis, hPMVEC were treated with siRNA against src (siRNAsrc), siRNA against yes (siRNAyes), or their respective scramble controls. After recovery, the hPMVEC were treated with cytomix (LPS, IL-1β, TNF-α, and IFN-γ). Treatment with cytomix induced activation of the extracellular signal-regulated kinase (ERK) pathway and caspase-3-mediated apoptosis. Treatment with siRNAsrc blunted cytomix-induced ERK activation and enhanced cleaved caspase-3 levels, while treatment with siRNAyes enhanced cytomix-induced ERK activation and attenuated levels of cleaved caspase-3. Inhibition of the ERK pathway using U0126 enhanced cytomix-induced caspase-3 activity. Treatment of hPMVEC with cytomix induced Akt activation, which was inhibited by siRNAsrc. Inhibition of the phosphatidylinositol 3-kinase/Akt pathway using LY294002 prevented cytomix-induced ERK activation and augmented cytomix-induced caspase-3 cleavage. Together, our data demonstrate that, in hPMVEC, yes activation blunts the ERK cascade in response to cytomix, resulting in greater apoptosis, while cytomix-induced src activation induces the phosphatidylinositol 3-kinase pathway, which leads to activation of Akt and ERK and attenuation of apoptosis.

MicroRNA Regulation of Acute Lung Injury and Acute Respiratory Distress Syndrome

The acute respiratory distress syndrome (ARDS), a severe form of acute lung injury (ALI), is a very common condition associated with critically ill patients, which causes substantial morbidity and mortality worldwide. Despite decades of research, effective therapeutic strategies for clinical ALI/ARDS are not available. In recent years, microRNAs (miRNAs), small non-coding molecules have emerged as a major area of biomedical research as they post-transcriptionally regulate gene expression in diverse biological and pathological processes, including ALI/ARDS. In this context, this present review summarizes a large body of evidence implicating miRNAs and their target molecules in ALI/ARDS originating largely from studies using animal and cell culture model systems of ALI/ARDS. We have also focused on the involvement of miRNAs in macrophage polarization, which play a critical role in regulating the pathogenesis of ALI/ARDS. Finally, the possible future directions that might lead to novel therapeutic strategies for the treatment of ALI/ARDS are also reviewed. J. Cell. Physiol. 231: 2097-2106, 2016. © 2016 Wiley Periodicals, Inc.

Effect of total alkaloids from Alstonia scholaris on airway inflammation in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Alstonia scholaris (Apocynaceae) have been traditionally used for treatment of respiratory diseases in "dai" ethnopharmacy for hundreds years, especially for cough, asthma, phlegm, chronic obstructive pulmonary disease and so on. The formulas including the leaf extract have also been prescribed in hospitals and sold over the retail pharmacies.

AIM OF THE STUDY

A. scholaris is used as a traditional herbal medicine for the treatment of respiratory tract inflammation. However, there is no scientific evidence to validate the use of total alkaloids of A. scholaris in the literature. Here, we investigated the protective activity of total alkaloids (TA), extracted from the leaves of Alstonia scholaris, against lipopolysaccharide (LPS)-induced airway inflammation (AI) in rats.

MATERIALS AND METHODS

200 μg/μL LPS was instilled intratracheally in each rat, and then the modeling animals were divided into six groups (n=10, each) randomly: sham group, LPS group, Dexamethasone [1.5mg/kg, intra-gastricly (i.g.)] group, and three different doses (7.5, 15, and 30 mg/kg, i.g.) of total alkaloids-treated groups. Corresponding drugs or vehicles were orally administered once per day for 7 days consecutively. The concentration of albumin (ALB), alkaline phosphatase (AKP), lactate dehydrogenase (LDH), and the number of inflammatory cells in bronchoalveolar lavage fluid (BALF) were determined by fully automatic biochemical analyzer and blood counting instrument. Nitric oxide (NO) level, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activities were examined by multiskan spectrum, and histological change in the lungs was analyzed by H.E. staining. The levels of inflammatory cytokine tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) were measured using ELISA.

RESULTS

Total alkaloids decreased the percentage of neutrophil, number of WBC, levels of ALB, AKP and LDH in the BALF, while increased the content of ALB in serum. It also improved SOD activity and increased NO level in the lungs, serum and BALF, and reduced the concentration of MDA in the lungs. Total alkaloids also inhibited the production of inflammatory cytokines TNF-α and IL-8 in the BALF and lung. Finally, histopathological examination indicated that total alkaloids attenuated tissue injury of the lungs in LPS-induced AI.

CONCLUSIONS

Total alkaloids have an inhibitory effect against LPS-induced airway inflammation in rats.

Emerging therapies for the prevention of acute respiratory distress syndrome

The development of acute respiratory distress syndrome (ARDS) carries significant risk of morbidity and mortality. To date, pharmacological therapy has been largely ineffective for patients with ARDS. We present our personal review aimed at outlining current and future directions for the pharmacological prevention of ARDS. Several available risk-stratification or prediction score strategies for identification of patients at risk of ARDS have been reported. Although not ready for clinical everyday use, they are and will be instrumental in the ongoing and future trials of pharmacoprevention of ARDS.Several systemic medications established the potential role in ARDS prevention based on the preclinical studies and observational data. Due to potential for systemic adverse effects to neutralize any pharmacological benefits of systemic therapy, inhaled medications appear particularly attractive candidates for ARDS prevention. This is because of their direct delivery to the site of proposed action (lungs), while the pulmonary epithelial surface is still functional.We postulate that overall morbidity and mortality rates from ARDS in the future will be contingent upon decreasing the overall incidence of ARDS through effective identification of those at risk and early application of proven supportive care and pharmacological interventions.

Postperfusion lung syndrome: physiopathology and therapeutic options

Postperfusion lung syndrome is rare but can be lethal. The underlying mechanism remains uncertain but triggering inflammatory cascades have become an accepted etiology. A better understanding of the pathophysiology and the roles of inflammatory mediators in the development of the syndrome is imperative in the determination of therapeutic options and promotion of patients' prognosis and survival. Postperfusion lung syndrome is similar to adult respiratory distress syndrome in clinical features, diagnostic approaches and management strategies. However, the etiologies and predisposing risk factors may differ between each other. The prognosis of the postperfusion lung syndrome can be poorer in comparison to acute respiratory distress syndrome due to the secondary multiple organ failure and triple acid-base imbalance. Current management strategies are focusing on attenuating inflammatory responses and preventing from pulmonary ischemia-reperfusion injury. Choices of cardiopulmonary bypass circuit and apparatus, innovative cardiopulmonary bypass techniques, modified surgical maneuvers and several pharmaceutical agents can be potential preventive strategies for acute lung injury during cardiopulmonary bypass.

Pulmonary histopathologic abnormalities and predictor variables in autopsies of burned pediatric patients

Pulmonary abnormalities occur in 30-80% of fatalities after burn. The objective of our study is to investigate lung pathology in autopsy tissues of pediatric burn patients.

METHODS

Three scientists with pathology training in pediatric burn care reviewed masked autopsy slides of burned children who died after admission to a burn center from 2002 to 2012 (n=43). Autopsy lung tissue was assigned scores for histologic abnormalities in 9 categories, including alveolar and interstitial fibrosis, hyaline membranes, and type II epithelial cell proliferation. Scores were then tested for correlation with age, TBSA burn, number of days between burn and death, time between burn and admission, and the presence of inhalation injury using analyses with linear models.

RESULTS

Type II epithelial cell proliferation was significantly more common in cases with a longer time between burn and admission (p<0.02). Interstitial fibrosis was significantly more severe in cases with longer survival after burn (p<0.01). The scores for protein were significantly higher in cases with longer survival after burn (p<0.03). Enlarged air spaces were significantly more prominent in cases with longer survival after burn (p<0.01), and in cases with the presence of inhalation injury (p<0.01).

CONCLUSIONS

Histological findings associated with diffuse alveolar damage (DAD), which is the pathological correlate of the acute respiratory distress syndrome (ARDS), were seen in approximately 42% of autopsies studied. Protein-rich alveolar edema, which is the abnormality that leads to ARDS, may occur from multiple causes, including inhalation injury.

High tidal volume decreases adult respiratory distress syndrome, atelectasis, and ventilator days compared with low tidal volume in pediatric burned patients with inhalation injury

BACKGROUND

Inhalation injury, which is among the causes of acute lung injury and acute respiratory distress syndrome (ARDS), continues to represent a significant source of mortality in burned patients. Inhalation injury often requires mechanical ventilation, but the ideal tidal volume strategy is not clearly defined in burned pediatric patients. The aim of this study was to determine the effects of low and high tidal volume on the number of ventilator days, ventilation pressures, and incidence of atelectasis, pneumonia, and ARDS in pediatric burned patients with inhalation injury within 1 year post burn injury.

METHODS

From 1986 to 2014, inhalation injury was diagnosed by bronchoscopy in pediatric burned patients (n = 932). Patients were divided into 3 groups: unventilated (n = 241), high tidal volume (HTV, 15 ± 3 mL/kg, n = 190), and low tidal volume (LTV, 9 ± 3 mL/kg, n = 501).

RESULTS

High tidal volume was associated with significantly decreased ventilator days (p < 0.005) and maximum positive end expiratory pressure (p < 0.0001) and significantly increased maximum peak inspiratory pressure (p < 0.02) and plateau pressure (p < 0.02) compared with those in patients with LTV. The incidence of atelectasis (p < 0.0001) and ARDS (p < 0.02) was significantly decreased with HTV compared with LTV. However, the incidence of pneumothorax was significantly increased in the HTV group compared with the LTV group (p < 0.03).

CONCLUSIONS

High tidal volume significantly decreases ventilator days and the incidence of both atelectasis and ARDS compared with low tidal volume in pediatric burned patients with inhalation injury. Therefore, the use of HTV may interrupt sequences leading to lung injury in our patient population.

The effects of exogenous surfactant treatment in a murine model of two-hit lung injury

BACKGROUND

Because pulmonary endogenous surfactant is altered during acute respiratory distress syndrome, surfactant replacement may improve clinical outcomes. However, trials of surfactant use have had mixed results. We designed this animal model of unilateral (right) lung injury to explore the effect of exogenous surfactant administered to the injured lung on inflammation in the injured and noninjured lung.

METHODS

Mice underwent hydrochloric acid instillation (1.5 mL/kg) into the right bronchus and prolonged (7 hours) mechanical ventilation (25 mL/kg). After 3 hours, mice were treated with 1 mL/kg exogenous surfactant (Curosurf®) (surf group) or sterile saline (NaCl 0.9%) (vehicle group) in the injured (right) lung or did not receive any treatment (hydrochloric acid, ventilator-induced lung injury). Gas exchange, lung compliance, and bronchoalveolar inflammation (cells, albumin, and cytokines) were evaluated. After a significant analysis of variance (ANOVA) test, Tukey post hoc test was used for statistical analysis.

RESULTS

At least 8 to 10 mice in each group were analyzed for each evaluated variable. Surfactant treatment significantly increased both the arterial oxygen tension to fraction of inspired oxygen ratio and respiratory system static compliance (P = 0.027 and P = 0.007, respectively, for surf group versus vehicle). Surfactant therapy increased indices of inflammation in the acid-injured lung compared with vehicle: inflammatory cells (685 [602-773] and 216 [125-305] × 1000/mL, respectively; P < 0.001) and albumin in bronchoalveolar lavage (BAL) (1442 ± 588 and 743 ± 647 μg/mL, respectively; P = 0.027). These differences were not found (P = 0.96 and P = 0.54) in the contralateral (uninjured) lung (inflammatory cells 131 [78-195] and 119 [87-149] × 1000/mL and albumin 135 ± 100 and 173 ± 115 μg/mL).

CONCLUSIONS

Exogenous surfactant administration to an acid-injured right lung improved gas exchange and whole respiratory system compliance. However, markers of inflammation increased in the right (injured) lung, although this result was not found in the left (uninjured) lung. These data suggest that the mechanism by which surfactant improves lung function may involve both uninjured and injured alveoli.

Therapeutic Effects of Bone Marrow-Derived Mesenchymal Stem Cells in Models of Pulmonary and Extrapulmonary Acute Lung Injury

Bone marrow-derived mesenchymal stem cells (MSCs) offer a promising therapy for acute lung injury (ALI). However, whether the same MSC treatments possess similar potential for different ALI models is not fully clear. The present study evaluated the distribution and therapeutic effects of intravenous MSC administration for the treatment of intratracheal lipopolysaccharide (LPS)-induced intrapulmonary ALI and intravenous LPS/zymosan-induced extrapulmonary ALI, matched with lung injury severity, at 30 min and 1, 3, and 7 days. We found that MSC transplantation attenuated lung injury and inhibited lung inflammation in both ALI models. The benefits of MSCs were more significant in the intrapulmonary ALI mice. In vivo and ex vivo fluorescence imaging showed that MSCs primarily homed into the lung. However, more MSCs were recruited into the lungs of the intrapulmonary ALI mice than those of the extrapulmonary ALI mice over the time course. A few MSCs were also detected in the liver and spleen at days 3 and 7. In addition, the two ALI models showed different extrapulmonary organ dysfunction. A lower percentage of cell apoptosis and SDF-1α levels was found in the liver and spleen of the intrapulmonary ALI mice than in those of the extrapulmonary ALI mice. These results suggested that the two ALI models were accompanied with different degrees of extrapulmonary organ damage, which resulted in differences in the trafficking and accumulation of MSCs to the injured lung and consequently accounted for different therapeutic effects of MSCs for lung repair in the two ALI models. These data suggest that intravenous administration of MSCs has a greater potential for the treatment of intrapulmonary ALI than extrapulmonary ALI matched with lung injury severity; these differences were due to more recruitment of MSCs in the lungs of intrapulmonary ALI mice than those of extrapulmonary ALI mice. This finding may contribute to the clinical use of MSCs for the treatment of ALI.

DNaseI protects against Paraquat-induced acute lung injury and pulmonary fibrosis mediated by mitochondrial DNA

BACKGROUND

Paraquat (PQ) poisoning is a lethal toxicological challenge that served as a disease model of acute lung injury and pulmonary fibrosis, but the mechanism is undetermined and no effective treatment has been discovered.

METHODS AND FINDINGS

We demonstrated that PQ injures mitochondria and leads to mtDNA release. The mtDNA mediated PBMC recruitment and stimulated the alveolar epithelial cell production of TGF-β1 in vitro. The levels of mtDNA in circulation and bronchial alveolar lavage fluid (BALF) were elevated in a mouse of PQ-induced lung injury. DNaseI could protect PQ-induced lung injury and significantly improved survival. Acute lung injury markers, such as TNFα, IL-1β, and IL-6, and marker of fibrosis, collagen I, were downregulated in parallel with the elimination of mtDNA by DNaseI. These data indicate a possible mechanism for PQ-induced, mtDNA-mediated lung injury, which may be shared by other causes of lung injury, as suggested by the same protective effect of DNaseI in bleomycin-induced lung injury model. Interestingly, increased mtDNA in the BALF of patients with amyopathic dermatomyositis-interstitial lung disease can be appreciated.

CONCLUSIONS

DNaseI targeting mtDNA may be a promising approach for the treatment of PQ-induced acute lung injury and pulmonary fibrosis that merits fast tracking through clinical trials.