Effects of N-acetylcysteine treatment in acute respiratory distress syndrome: A meta-analysis

Metagenomic Analysis of Gut Microbiome of Persistent Pulmonary Hypertension of the Newborn

Persistent pulmonary hypertension of the newborn (PPHN) is one of the most common diseases in the neonatal intensive care unit which severely affects neonatal survival. Gut microbes play an increasingly important role in human health, but there are rarely reported how gut microbiota contribute to PPHN. In our study, the metagenomic sequencing of feces from 12 PPHN's neonates and 8 controls were performed to expose the relation between neonatal gut microbes and PPHN disease. Firstly, we found that the abundance of Actinobacteria, Proteobacteria, Bacteroidetes were significantly increased in PPHN compared with controls, but the Firmicutes components was reduced. And some pathogenic strains (like Vibrio metschnikovii) were significantly enriched in the PPHN compared with controls. Secondly, functional annotation of genes found that PPHN up-regulated transmembrane transport, but down-regulated ribosome and ATP binding. Lastly, microbial metabolic pathway enrichment analysis indicated that some metabolic pathway in PPHN were conflicting and contradictory, showed that an abnormally increased metabolism, disturbed protein synthesis and genomic instability in the PPHN neonate. Our results contribute to understanding the changes in the species and function of gut microbiota in PPHN, thus providing a theoretical basis for the explanation and treatment of PPHN.

The interplay between mitophagy and mitochondrial ROS in acute lung injury

Mitochondria orchestrate the production of new mitochondria and the removal of damaged ones to dynamically maintain mitochondrial homeostasis through constant biogenesis and clearance mechanisms. Mitochondrial quality control particularly relies on mitophagy, defined as selective autophagy with mitochondria-targeting specificity. Most ROS are derived from mitochondria, and the physiological concentration of mitochondrial ROS (mtROS) is no longer considered a useless by-product, as it has been proven to participate in immune and autophagy pathway regulation. However, excessive mtROS appears to be a pathogenic factor in several diseases, including acute lung injury (ALI). The interplay between mitophagy and mtROS is complex and closely related to ALI. Here, we review the pathways of mitophagy, the intricate relationship between mitophagy and mtROS, the role of mtROS in the pathogenesis of ALI, and their effects and related progression in ALI induced by different conditions.

Effects of acetylcysteine on micro-inflammation and pulmonary ventilation in chronic obstructive pulmonary disease exacerbation

BACKGROUND

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a serious complication of chronic obstructive pulmonary disease, often characterized by increased morbidity and mortality. In traditional Chinese medicine, AECOPD is linked to phlegm-heat and blood-stasis, presenting symptoms like thick sputum, fever, and chest pain. It has been shown that acetylcysteine inhalation in conjunction with conventional therapy significantly reduced inflammatory markers and improved lung function parameters in patients with AECOPD, suggesting that acetylcysteine may be an important adjunctive therapy for patients with phlegm-heat-blood stasis type AECOPD.

AIM

To investigate the effect of acetylcysteine on microinflammation and lung ventilation in patients with phlegm-heat and blood-stasis-type AECOPD.

METHODS

One hundred patients with phlegm-heat and blood-stasis-type AECOPD were randomly assigned to two groups. The treatment group received acetylcysteine inhalation (10% solution, 5 mL, twice daily) along with conventional therapy, whereas the control group received only conventional therapy. The treatment duration was 14 d. Inflammatory markers (C-reactive protein, interleukin-6, and tumor necrosis factor-alpha) in the serum and sputum as well as lung function parameters (forced expiratory volume in one second, forced vital capacity, and peak expiratory flow) were assessed pre- and post-treatment. Acetylcysteine inhalation led to significant reductions in inflammatory markers and improvements in lung function parameters compared to those in the control group (P < 0.05). This suggests that acetylcysteine could serve as an effective adjunct therapy for patients with phlegm-heat and blood-stasis-type AECOPD.

RESULTS

Acetylcysteine inhalation significantly reduced inflammatory markers in the serum and sputum and improved lung ventilation function parameters in patients with phlegm-heat and blood-stasis type AECOPD compared with the control group. These differences were statistically significant (P < 0.05). The study concluded that acetylcysteine inhalation had a positive effect on microinflammation and lung ventilation function in patients with this type of AECOPD, suggesting its potential as an adjuvant therapy for such cases.

CONCLUSION

Acetylcysteine inhalation demonstrated significant improvements in reducing inflammatory markers in the serum and sputum, as well as enhancing lung ventilation function parameters in patients with phlegm-heat and blood-stasis type AECOPD. These findings suggest that acetylcysteine could serve as a valuable adjuvant therapy for individuals with this specific type of AECOPD, offering benefits for managing microinflammation and optimizing lung function.

An update on the pharmacological management of acute respiratory distress syndrome

INTRODUCTION

Acute respiratory distress syndrome (ARDS) is characterized by acute inflammatory injury to the lungs, alterations in vascular permeability, loss of aerated tissue, bilateral infiltrates, and refractory hypoxemia. ARDS is considered a heterogeneous syndrome, which complicates the search for effective therapies. The goal of this review is to provide an update on the pharmacological management of ARDS.

AREAS COVERED

The difficulties in finding effective pharmacological therapies are mainly due to the challenges in designing clinical trials for this unique, varied population of critically ill patients. Recently, some trials have been retrospectively analyzed by dividing patients into hyper-inflammatory and hypo-inflammatory sub-phenotypes. This approach has led to significant outcome improvements with some pharmacological treatments that previously failed to demonstrate efficacy, which suggests that a more precise selection of ARDS patients for clinical trials could be the key to identifying effective pharmacotherapies. This review is provided after searching the main studies on this topics on the PubMed and clinicaltrials.gov databases.

EXPERT OPINION

The future of ARDS therapy lies in precision medicine, innovative approaches to drug delivery, immunomodulation, cell-based therapies, and robust clinical trial designs. These should lead to more effective and personalized treatments for patients with ARDS.

Exploring the role of antioxidants in sepsis-associated oxidative stress: a comprehensive review

Sepsis is a potentially fatal condition characterized by organ dysfunction caused by an imbalanced immune response to infection. Although an increased inflammatory response significantly contributes to the pathogenesis of sepsis, several molecular mechanisms underlying the progression of sepsis are associated with increased cellular reactive oxygen species (ROS) generation and exhausted antioxidant pathways. This review article provides a comprehensive overview of the involvement of ROS in the pathophysiology of sepsis and the potential application of antioxidants with antimicrobial properties as an adjunct to primary therapies (fluid and antibiotic therapies) against sepsis. This article delves into the advantages and disadvantages associated with the utilization of antioxidants in the therapeutic approach to sepsis, which has been explored in a variety of animal models and clinical trials. While the application of antioxidants has been suggested as a potential therapy to suppress the immune response in cases where an intensified inflammatory reaction occurs, the use of multiple antioxidant agents can be beneficial as they can act additively or synergistically on different pathways, thereby enhancing the antioxidant defense. Furthermore, the utilization of immunoadjuvant therapy, specifically in septic patients displaying immunosuppressive tendencies, represents a promising advancement in sepsis therapy.

Impact of antioxidants on PM2.5 oxidative potential, radical level, and cytotoxicity

Antioxidants are typically seen as agents that mitigate environmental health risks due to their ability to scavenge free radicals. However, our research presents a paradox where these molecules, particularly those within lung fluid, act as prooxidants in the presence of airborne particulate matter (PM2.5), thus enhancing PM2.5 oxidative potential (OP). In our study, we examined a range of antioxidants found in the respiratory system (e.g., vitamin C, glutathione (GSH), and N-acetylcysteine (NAC)), in plasma (vitamin A, vitamin E, and β-carotene), and in food (tert-butylhydroquinone (TBHQ)). We aimed to explore antioxidants' prooxidant and antioxidant interactions with PM2.5 and the resulting OP and cytotoxicity. We employed OH generation assays and electron paramagnetic resonance assays to assess the pro-oxidative and anti-oxidative effects of antioxidants. Additionally, we assessed cytotoxicity interaction using a Chinese hamster ovary cell cytotoxicity assay. Our findings revealed that, in the presence of PM2.5, all antioxidants except vitamin E significantly increased the PM2.5 OP by generating more OH radicals (OH generation rate: 0.16-24.67 pmol·min-1·m-3). However, it's noteworthy that these generated OH radicals were at least partially neutralized by the antioxidants themselves. Among the pro-oxidative antioxidants, vitamin A, β-carotene, and TBHQ showed the least ability to quench these radicals, consistent with their observed impact in enhancing PM2.5 cytotoxicity (PM2.5 LC50 reduced to 91.2 %, 88.8 %, and 75.1 % of PM2.5's original level, respectively). Notably, vitamin A and TBHQ-enhanced PM2.5 OP were strongly associated with the presence of metals and organic compounds, particularly with copper (Cu) contributing significantly (35 %) to TBHQ's pro-oxidative effect. Our study underscores the potential health risks associated with the interaction between antioxidants and ambient pollutants.

Anti-inflammatory therapies for acute respiratory distress syndrome

INTRODUCTION

Treatments for the acute respiratory distress syndrome (ARDS) are mainly supportive, and ventilatory management represents a key approach in these patients. Despite progress in pharmacotherapy, anti-inflammatory strategies for the treatment of ARDS have shown controversial results. Positive outcomes with pharmacologic and nonpharmacologic treatments have been found in two different biological subphenotypes of ARDS, suggesting that, with a personalized medicine approach, pharmacotherapy for ARDS can be effective.

AREAS COVERED

This article reviews the literature concerning anti-inflammatory therapies for ARDS, focusing on pharmacological and stem-cell therapies, including extracellular vesicles.

EXPERT OPINION

Despite advances, ARDS treatments remain primarily supportive. Ventilatory and fluid management are important strategies in these patients that have demonstrated significant impacts on outcome. Anti-inflammatory drugs have shown some benefits, primarily in preclinical research and in specific clinical scenarios, but no recommendations are available from guidelines to support their use in patients with ARDS, except in particular settings such as different subphenotypes, specific etiologies, or clinical trials. Personalized medicine seems promising insofar as it may identify specific subgroups of patients with ARDS who may benefit from anti-inflammatory treatment. However, additional efforts are needed to move subphenotype characterization from bench to bedside.

N-acetylcysteine reduces severity and mortality in COVID-19 patients: A systematic review and meta-analysis

Objectives

Recent clinical studies suggest that oxidative stress is one of the key players in the pathogenesis of coronavirus disease 2019 (COVID-19), and N-acetylcysteine (NAC), a potent antioxidant, has been shown to improve clinical outcomes in COVID-19 patients. We conducted a systematic review and meta-analysis of the literature published on the therapeutic intervention of NAC on COVID-19 infection.

Methods

We searched PubMed, Google Scholar, and Science Direct. We identified and screened eight studies with 20,503 participants, including 2,852 in the NAC-treated group and 17,651 in the placebo group, which reported the effect of NAC on COVID-19 infection. A meta-analysis was performed using forest plots under fixed effect estimates based on the standardized mean difference (SMD) and risk ratio (RR).

Results

Pooled analysis showed that NAC was associated with lower mortality in patients with COVID-19 compared with the placebo group [RR, 0.65; (95% CI: 0.56 to 0.75); p < 0.0001]. Similarly, C-reactive protein (CRP) [SMD, -0.32; (95% CI: -56 to -0.09); p = 0.0070] and D-dimer [SMD, -0.35, (95% CI: -0.59 to -0.10; p = 0.0062] levels were significantly decreased, and the oxygenation marker, PaO2/FiO2 ratio, was increased in the NAC-treated group compared with the placebo group [SMD, 0.76; (95% CI: 0.48 to 1.03); p < 0.0001].

Conclusion

Although the number of included studies was minimal, this meta-analysis suggests that NAC may have a positive effect on COVID-19 outcomes, specifically, a significant decrease in CRP and D-dimer levels and a significant increase in oxygen saturation, which decreased mortality. We have also presented a comprehensive review of the role and mechanisms of NAC in patients with COVID-19.

THE ROLE OF NEUTROPHIL EXTRACELLULAR TRAPS (NETS) IN THE IMMUNOPATHOGENESIS OF SEVERE COVID-19: POTENTIAL IMMUNOTHERAPEUTIC STRATEGIES REGULATING NET FORMATION AND ACTIVITY

The role of neutrophil granulocytes (NG) in the pathogenesis of COVID-19 is associated with the recruitment of NG into inflammatory foci, activation of their functions and enhanced formation of neutrophil extracellular networks (NETs). In this review, we analyzed a fairly large volume of scientific literature devoted to the peculiarities of the formation of NETs, their role in the pathogenesis of COVID-19, participation in the occurrence of immunothrombosis, vasculitis, acute respiratory distress syndrome, cytokine storm syndrome, multi-organ lesions. Convincing data are presented that clearly indicate the significant involvement of NETs in the immunopathogenesis of COVID-19 and the associated severe complications resulting from the intensification of the inflammation process, which is key for the course of infection caused by the SARS-CoV-2 virus. The presented role of NG and NETs, along with the role of other immune system cells and pro-inflammatory cytokines, is extremely important in understanding the development of an overactive immune response in severe COVID-19. The obtained scientific results, available today, allow identifying the possibilities of regulatory effects on hyperactivated NG, on the formation of NETs at various stages and on limiting the negative impact of already formed NETs on various tissues and organs. All of the above should help in the creation of new, specialized immunotherapy strategies designed to increase the chances of survival, reduce the severity of clinical manifestations in patients with COVID-19, as well as significantly reduce mortality rates. Currently, it is possible to use existing drugs and a number of new drugs are being developed, the action of which can regulate the amount of NG, positively affect the functions of NG and limit the intensity of NETs formation. Continuing research on the role of hyperactive NG and netosis, as well as understanding the mechanisms of regulation of the phenomenon of formation and restriction of NETs activity in severe COVID-19, apparently, are a priority, since in the future the new data obtained could become the basis for the development of targeted approaches not only to immunotherapy aimed at limiting education and blocking negative effects already formed NETs in severe COVID-19, but also to immunotherapy, which could be used in the complex treatment of other netopathies, first of all, autoimmune diseases, auto-inflammatory syndromes, severe purulent-inflammatory processes, including bacterial sepsis and hematogenous osteomyelitis.

Challenges in ARDS Definition, Management, and Identification of Effective Personalized Therapies

Over the last decade, the management of acute respiratory distress syndrome (ARDS) has made considerable progress both regarding supportive and pharmacologic therapies. Lung protective mechanical ventilation is the cornerstone of ARDS management. Current recommendations on mechanical ventilation in ARDS include the use of low tidal volume (VT) 4-6 mL/kg of predicted body weight, plateau pressure (PPLAT) < 30 cmH2O, and driving pressure (∆P) < 14 cmH2O. Moreover, positive end-expiratory pressure should be individualized. Recently, variables such as mechanical power and transpulmonary pressure seem promising for limiting ventilator-induced lung injury and optimizing ventilator settings. Rescue therapies such as recruitment maneuvers, vasodilators, prone positioning, extracorporeal membrane oxygenation, and extracorporeal carbon dioxide removal have been considered for patients with severe ARDS. Regarding pharmacotherapies, despite more than 50 years of research, no effective treatment has yet been found. However, the identification of ARDS sub-phenotypes has revealed that some pharmacologic therapies that have failed to provide benefits when considering all patients with ARDS can show beneficial effects when these patients were stratified into specific sub-populations; for example, those with hyperinflammation/hypoinflammation. The aim of this narrative review is to provide an overview on current advances in the management of ARDS from mechanical ventilation to pharmacological treatments, including personalized therapy.

N-acetylcysteine as adjuvant therapy for hospitalized Covid-19 patients: A single-center prospective cohort study

Background

Whilst over two years have passed since the COVID-19 pandemic's emergence, the proper management of the disease remains challenging. N-acetylcysteine (NAC) as a potentially effective therapeutic option has been suggested by studies, while the exact clinical role of this agent is yet to be evaluated.

Methods

This prospective case-control study was conducted in a major referral respiratory center in Tehran, Iran. We enrolled 217 patients treated with an intravenous daily dose of 1500 mg NAC as a case group; and 245 control patients who did not receive NAC. Two groups were matched based on other treatments, socio-demographics, medical history, and comorbidities.

Results

After ten days of adjuvant therapy with NAC, patients in the NAC group and control group had median room-air SpO2 of 91% and 88%, respectively (P=0.02). Also, the SpO2 to FiO2 ratio had a median of 463 and 421 in the case and control groups, respectively (P=0.01). Furthermore, the case group's hospitalization period was three days shorter (P=0.002). Further, cough, dyspnea, and decreased appetite were reported to have a significantly lower incidence in the case group (P=0.03, 0.001, 0.008).

Conclusion

We showed that a daily intravenous dose of NAC in hospitalized COVID-19 patients could shorten the hospital stay and improve some clinical symptoms; however, it does not remarkably improve the risk of ICU admission and the 28 days in-hospital mortality rate.

Profound Effect of Pulmonary Surfactant on the Treatment of Preterm Infants with Respiratory Distress Syndrome

Inherited diseases caused by dysfunction of pulmonary surfactant metabolism or surfactant dysfunction have recently been considered the underlying causes of neonatal and pediatric respiratory diseases. Respiratory distress syndrome in premature infants is a common respiratory disease in pediatrics. It is caused by underdeveloped lungs in infants and a lack of active substances on the surface of the alveoli, which leads to insufficiency of lung function, which can lead to difficulty breathing, increased heart rate, facial bruising, and more. Neonatal Respiratory Distress Syndrome is a very dangerous disease with a high mortality rate and a great threat to children's lives and health. Therefore, enough attention and treatment should be caused in clinical practice. Natural pulmonary surfactant (PS) has achieved positive effects in the treatment of neonatal respiratory distress syndrome (RDS), reducing neonatal mortality, the application of mechanical ventilation, and the occurrence of late complications. To further explore the role of pulmonary surfactants in the treatment of neonatal respiratory distress syndrome, to analyze the best time to use PS to prevent RDS, this paper has selected premature infants with RDS received by the neonatal department of a hospital in a province from March 2019 to October 2020 to compare the efficacy of pulmonary surfactant (PS) in preterm infants with respiratory distress syndrome (RDS). The experiment has found that the average mechanical ventilation time (5.1 d) and oxygen therapy time (7.3 d) in the early group are shorter than the average mechanical ventilation time (6.4 d) and oxygen therapy time (10.6 d) in the late group. It has been demonstrated that early administration of pulmonary surfactant (PS) therapy is of great help in improving respiratory distress syndrome in premature infants.

The Role of Antioxidant Agent (N-Acetylcysteine) in Oleic Acid-Induced Acute Lung Injury in a Rat Model

Context

Reactive oxygen species (ROS) produced by inflammatory cells play a major role in mediating lung injury in sepsis or hyperoxic lung injury.

Aims

N-Acetylcysteine (NAC), an antioxidant, was examined in this research to see whether it helps prevent acute lung injury (ALI).

Materials and methods

Experiments were performed on Charles-Foster strain healthy male adult albino rats. All the animals were randomly divided into one control and two experimental groups. In control/group I, saline was administered, and cardiorespiratory parameters were recorded. Oleic acid (OA) was administered in group II to produce ALI. In group III, OA was administered to NAC-pretreated rats, and cardiorespiratory parameters were recorded to observe the effect of NAC on ALI. This study used analysis of variance (ANOVA) with two factors and a post hoc test (multiple comparisons - least significant difference (LSD) test) for statical analysis. For determining survival time, the Mantel-Cox test and Kaplan-Meier survival curves were used. A P value < 0.05 was considered significant.

Results

Respiratory arrest, pulmonary edema, and reduced partial pressure of oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) ratio were all indications of OA-induced ALI in rats. The animals in the NAC + OA group had better respiratory and cardiac statistics than those in the OA alone group, and their survival duration was extended. However, NAC pretreatment could not protect the animals against the development of pulmonary edema.

Conclusions

These observations indicate that NAC (an antioxidant agent) protected rats against ALI in the initial phase and prolonged the survival time but failed to prevent the development of pulmonary edema.

Treatment for acute respiratory distress syndrome in adults: A narrative review of phase 2 and 3 trials

INTRODUCTION

Ventilatory management and general supportive care of acute respiratory distress syndrome (ARDS) in the adult population have led to significant clinical improvements, but morbidity and mortality remain high. Pharmacologic strategies acting on the coagulation cascade, inflammation, oxidative stress, and endothelial cell injury have been targeted in the last decade for patients with ARDS, but only a few of these have shown potential benefits with a meaningful clinical response and improved patient outcomes. The lack of availability of specific pharmacologic treatments for ARDS can be attributed to its complex pathophysiology, different risk factors, huge heterogeneity, and difficult classification into specific biological phenotypes and genotypes.

AREAS COVERED

In this narrative review, we briefly discuss the relevance and current advances in pharmacologic treatments for ARDS in adults and the need for the development of new pharmacological strategies.

EXPERT OPINION

Identification of ARDS phenotypes, risk factors, heterogeneity, and pathophysiology may help to design clinical trials personalized according to ARDS-specific features, thus hopefully decreasing the rate of failed clinical pharmacologic trials. This concept is still under clinical investigation and needs further development.

Dendrimer nanotherapy for severe COVID-19 attenuates inflammation and neurological injury markers and improves outcomes in a phase2a clinical trial

Hyperinflammation triggered by SARS-CoV-2 is a major cause of disease severity, with activated macrophages implicated in this response. OP-101, a hydroxyl-polyamidoamine dendrimer-N-acetylcysteine conjugate that specifically targets activated macrophages, improves outcomes in preclinical models of systemic inflammation and neuroinflammation. In this multicenter, randomized, double-blind, placebo-controlled, adaptive phase 2a trial, we evaluated safety and preliminary efficacy of OP-101 in patients with severe COVID-19. Twenty-four patients classified as having severe COVID-19 with a baseline World Health Organization seven-point ordinal scale of ≥5 were randomized to receive a single intravenous dose of placebo (n = 7 patients) or OP-101 at 2 (n = 6), 4 (n = 6), or 8 mg/kg (n = 5 patients). All study participants received standard of care, including corticosteroids. OP-101 at 4 mg/kg was better than placebo at decreasing inflammatory markers; OP-101 at 4 and 8 mg/kg was better than placebo at reducing neurological injury markers, (neurofilament light chain and glial fibrillary acidic protein). Risk for the composite outcome of mechanical ventilation or death at 30 and 60 days after treatment was 71% (95% CI: 29%, 96%) for placebo and 18% (95% CI: 4%, 43%; P = 0.021) for the pooled OP-101 treatment arms. At 60 days, 3 of 7 patients given placebo and 14 of 17 OP-101-treated patients were surviving. No drug-related adverse events were reported. These data show that OP-101 was well tolerated and may have potential to treat systemic inflammation and neuronal injury, reducing morbidity and mortality in hospitalized patients with severe COVID-19.

Do Diet and Dietary Supplements Mitigate Clinical Outcomes in COVID-19?

The coronavirus disease 2019 (COVID-19) has caused a pandemic and upheaval that health authorities and citizens around the globe are still grappling with to this day. While public health measures, vaccine development, and new therapeutics have made great strides in understanding and managing the pandemic, there has been an increasing focus on the potential roles of diet and supplementation in disease prevention and adjuvant treatment. In the literature, the impact of nutrition on other respiratory illnesses, including the common cold, pneumonia, and influenza, has been widely demonstrated in both animal and human models. However, there is much less research on the impact related to COVID-19. The present study discusses the potential uses of diets, vitamins, and supplements, including the Mediterranean diet, glutathione, zinc, and traditional Chinese medicine, in the prevention of infection and severe illness. The evidence demonstrating the efficacy of diet supplementation on infection risk, disease duration, severity, and recovery is mixed and inconsistent. More clinical trials are necessary in order to clearly demonstrate the contribution of nutrition and to guide potential therapeutic protocols.

Lung targeted liposomes for treating ARDS

Acute Respiratory Distress Syndrome (ARDS), associated with Covid-19 infections, is characterized by diffuse lung damage, inflammation and alveolar collapse that impairs gas exchange, leading to hypoxemia and patient’ mortality rates above 40%. Here, we describe the development and assessment of 100-nm liposomes that are tailored for pulmonary delivery for treating ARDS, as a model for lung diseases. The liposomal lipid composition (primarily DPPC) was optimized to mimic the lung surfactant composition, and the drug loading process of both methylprednisolone (MPS), a steroid, and N-acetyl cysteine (NAC), a mucolytic agent, reached an encapsulation efficiency of 98% and 92%, respectively. In vitro, treating lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages with the liposomes decreased TNFα and nitric oxide (NO) secretion, while NAC increased the penetration of nanoparticles through the mucus. In vivo, we used LPS-induced lung inflammation model to assess the accumulation and therapeutic efficacy of the liposomes in C57BL/6 mice, either by intravenous (IV), endotracheal (ET) or IV plus ET nanoparticles administrations.

Using both administration methods, liposomes exhibited an increased accumulation profile in the inflamed lungs over 48 h. Interestingly, while IV-administrated liposomes distributed widely throughout the lung, ET liposomes were present in lungs parenchyma but were not detected at some distal regions of the lungs, possibly due to imperfect airflow regimes. Twenty hours after the different treatments, lungs were assessed for markers of inflammation. We found that the nanoparticle treatment had a superior therapeutic effect compared to free drugs in treating ARDS, reducing inflammation and TNFα, IL-6 and IL-1β cytokine secretion in bronchoalveolar lavage (BAL), and that the combined treatment, delivering nanoparticles IV and ET simultaneously, had the best outcome of all treatments. Interestingly, also the DPPC lipid component alone played a therapeutic role in reducing inflammatory markers in the lungs. Collectively, we show that therapeutic nanoparticles accumulate in inflamed lungs holding potential for treating lung disorders.

Significance

In this study we compare intravenous versus intratracheal delivery of nanoparticles for treating lung disorders, specifically, acute respiratory distress syndrome (ARDS). By co-loading two medications into lipid nanoparticles, we were able to reduce both inflammation and mucus secretion in the inflamed lungs. Both modes of delivery resulted in high nanoparticle accumulation in the lungs, intravenously administered nanoparticles reached lung endothelial while endotracheal delivery reached lung epithelial. Combining both delivery approaches simultaneously provided the best ARDS treatment outcome.

The effects of N-acetylcysteine on recovery biomarkers: A systematic review and meta-analysis of controlled trials

N-acetylcysteine (NAC) is one of the antioxidant supplements which is thought to improve recovery. Existing studies regarding NAC and recovery presented conflicting results. This systematic review and meta-analysis evaluated the existing trials and determined the efficacy of acute and chronic NAC administration on recovery biomarkers. PubMed, Web of Science, and Scopus were searched up to July 2021. The random effects or fixed effects model was applied in the meta-analysis. Sensitivity and subgroup analyses were performed. In case of the presence of publication bias, standard methods were applied. The meta-analysis comprised 37 papers (1,388 participants). All included studies were in English language. Acute NAC administration indicated no significant effects on lactate, pH, VO₂ , and CPK-MB ([SMD = -0.06 mmol/L; 95% CI: -0.40, 0.28; p = .714], [SMD = 0.17; 95% CI: -0.28, 0.62; p = .454], [SMD = -0.11 L/min; 95% CI: -0.63, 0.41; p = .686], and [SMD = -0.19 units/L; 95% CI: -0.62, 0.24; p = .395]). Additionally, no evidence of significant influence of chronic NAC administration on lactate, pH, VO₂ , and CK was revealed ([SMD = 0.01 mmol/L; 95% CI: -0.25, 0.27; p = .950], [SMD = -0.51; 95% CI: -1.73, 0.70; p = .424], [SMD = -0.18 L/min; 95% CI: -0.56, 0.20; p = .361], and [SMD = -0.04 units/L; 95% CI: -0.36, 0.29; p = .821]). No considerable effect of NAC on recovery was found. PRACTICAL APPLICATIONS: Previous studies on the influence of NAC administration on recovery biomarkers have presented conflicting results. This systematic review and meta-analysis offers a broad range of detailed information on the influence of chronic and acute NAC supplementation outcomes regarding recovery biomarkers. Overall, the results support that NAC supplementation may not be effective in improving recovery biomarkers. However, subgroup analyses based on NAC dosage indicated the meaningful effect of NAC on CK-MB at the dosage of ≥100 mg/kg.

Friend or Foe? The Roles of Antioxidants in Acute Lung Injury

Acute lung injury (ALI) is an acute hypoxic respiratory insufficiency caused by various intra- and extra-pulmonary injury factors. The oxidative stress caused by excessive reactive oxygen species (ROS) produced in the lungs plays an important role in the pathogenesis of ALI. ROS is a "double-edged sword", which is widely involved in signal transduction and the life process of cells at a physiological concentration. However, excessive ROS can cause mitochondrial oxidative stress, leading to the occurrence of various diseases. It is well-known that antioxidants can alleviate ALI by scavenging ROS. Nevertheless, more and more studies found that antioxidants have no significant effect on severe organ injury, and may even aggravate organ injury and reduce the survival rate of patients. Our study introduces the application of antioxidants in ALI, and explore the mechanisms of antioxidants failure in various diseases including it.

Effect of Nebulized Heparin on Weaning off Intubated Patients with Acute Respiratory Distress Syndrome (ARDS) Admitted to Intensive Care Unit (ICU): A Randomized Clinical Trial

Background: Acute respiratory distress syndrome (ARDS) treatment is based on supportive care such as mechanical ventilation, prophylaxis of stress ulcer, prophylaxis of deep vein thrombosis (DVT), nutritional support, and treatment of underlying disease. Objectives: We aimed to investigate the effects of nebulized heparin on weaning off intubated ARDS patients admitted to the intensive care unit (ICU). Methods: In this double-blind clinical trial study, 60 patients with ARDS receiving routine care according to the ARDS protocol were randomly assigned into two groups: intervention group (receiving nebulized heparin 5000 u/BD for one week) and control group (receiving nebulized sterile water 2 cc/BD for one week). The respiratory index (PaO2/FiO2), pulmonary shunt percentage (measured by ABG), tidal volume, minute ventilation, admission duration in the ICU, and days of mechanical ventilation required were recorded for each patient for one week. Results: There was no significant difference in demographic data between the two groups. Inhaled heparin in patients with ARDS could significantly increase the respiratory index (PaO2/FiO2) and decrease pulmonary shunt percentage, minute ventilation, and tidal volume. It also significantly reduced the number of admission days in the ICU and the need for mechanical ventilation. Conclusions: The result of the present study showed that inhaled heparin in intubated ARDS patients admitted to the ICU improved respiratory and pulmonary status and reduced the need for mechanical ventilation and admission days in the ICU. Nebulizing heparin, as an anti-inflammatory and anti-coagulant agent, is an effective and safe medication for ARDS patients on mechanical ventilation.

SARS-CoV-2 infection and oxidative stress: Pathophysiological insight into thrombosis and therapeutic opportunities

The current coronavirus disease 2019 (COVID-19) pandemic has presented unprecedented challenges to global health. Although the majority of COVID-19 patients exhibit mild-to-no symptoms, many patients develop severe disease and need immediate hospitalization, with most severe infections associated with a dysregulated immune response attributed to a cytokine storm. Epidemiological studies suggest that overall COVID-19 severity and morbidity correlate with underlying comorbidities, including diabetes, obesity, cardiovascular diseases, and immunosuppressive conditions. Patients with such comorbidities exhibit elevated levels of reactive oxygen species (ROS) and oxidative stress caused by an increased accumulation of angiotensin II and by activation of the NADPH oxidase pathway. Moreover, accumulating evidence suggests that oxidative stress coupled with the cytokine storm contribute to COVID-19 pathogenesis and immunopathogenesis by causing endotheliitis and endothelial cell dysfunction and by activating the blood clotting cascade that results in blood coagulation and microvascular thrombosis. In this review, we survey the mechanisms of how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces oxidative stress and the consequences of this stress on patient health. We further shed light on aspects of the host immunity that are crucial to prevent the disease during the early phase of infection. A better understanding of the disease pathophysiology as well as preventive measures aimed at lowering ROS levels may pave the way to mitigate SARS-CoV-2-induced complications and decrease mortality.

Association of Low Molecular Weight Plasma Aminothiols with the Severity of Coronavirus Disease 2019

Objective

Aminothiols (glutathione (GSH), cysteinylglycine (CG)) may play an important role in the pathogenesis of coronavirus disease 2019 (COVID-19), but the possible association of these indicators with the severity of COVID-19 has not yet been investigated.

Methods

The total content (t) and reduced forms (r) of aminothiols were determined in patients with COVID-19 (n = 59) on admission. Lung injury was characterized by computed tomography (CT) findings in accordance with the CT0-4 classification.

Results

Low tGSH level was associated with the risk of severe COVID-19 (tGSH ≤ 1.5 μM, mild vs. moderate/severe: risk ratio (RR) = 3.09, p = 0.007) and degree of lung damage (tGSH ≤ 1.8 μM, CT < 2 vs. CT ≥ 2: RR = 2.14, p = 0.0094). The rGSH level showed a negative association with D-dimer levels (ρ = -0.599, p = 0.014). Low rCG level was also associated with the risk of lung damage (rCG ≤ 1.3 μM, CT < 2 vs. CT ≥ 2: RR = 2.28, p = 0.001). Levels of rCG (ρ = -0.339, p = 0.012) and especially tCG (ρ = -0.551, p = 0.004) were negatively associated with platelet count. In addition, a significant relationship was found between the advanced oxidation protein product level and tGSH in patients with moderate or severe but not in patients with mild COVID-19.

Conclusion

Thus, tGSH and rCG can be seen as potential markers for the risk of severe COVID-19. GSH appears to be an important factor to oxidative damage prevention as infection progresses. This suggests the potential clinical efficacy of correcting glutathione metabolism as an adjunct therapy for COVID-19.

Combined Metabolic Activators Accelerates Recovery in Mild-to-Moderate COVID-19

COVID-19 is associated with mitochondrial dysfunction and metabolic abnormalities, including the deficiencies in nicotinamide adenine dinucleotide (NAD+ ) and glutathione metabolism. Here it is investigated if administration of a mixture of combined metabolic activators (CMAs) consisting of glutathione and NAD+ precursors can restore metabolic function and thus aid the recovery of COVID-19 patients. CMAs include l-serine, N-acetyl-l-cysteine, nicotinamide riboside, and l-carnitine tartrate, salt form of l-carnitine. Placebo-controlled, open-label phase 2 study and double-blinded phase 3 clinical trials are conducted to investigate the time of symptom-free recovery on ambulatory patients using CMAs. The results of both studies show that the time to complete recovery is significantly shorter in the CMA group (6.6 vs 9.3 d) in phase 2 and (5.7 vs 9.2 d) in phase 3 trials compared to placebo group. A comprehensive analysis of the plasma metabolome and proteome reveals major metabolic changes. Plasma levels of proteins and metabolites associated with inflammation and antioxidant metabolism are significantly improved in patients treated with CMAs as compared to placebo. The results show that treating patients infected with COVID-19 with CMAs lead to a more rapid symptom-free recovery, suggesting a role for such a therapeutic regime in the treatment of infections leading to respiratory problems.

Effect of N-Acetylcysteine on the treatment of acute respiratory distress syndrome in mechanically ventilated patients admitted to the intensive care unit

Background: N-acetylcysteine (NAC) is an antioxidant derived from the amino acid cysteine and is one of the drugs used in the treatment of respiratory diseases. The aim of this study was to investigate the effect of NAC on the treatment of acute respiratory distress syndrome in mechanically ventilated patients admitted to the intensive care unit. Methods: This study was a randomized clinical trial. Patients under mechanical ventilation admitted to the intensive care unit were examined. Patients in the intervention group received daily 150 mg/kg of NAC on the first day of admission and then 50 mg/kg up to the fourth day of admission. Patients in the control group received routine care. The vital signs, level of consciousness, and other important variables were recorded. Data were analyzed using statistical tests and SPSS software version 24. Results: There was no significant difference between MAP, heart rate, respiratory rate, O2Sat, APACHE II score, and pulmonary capacity of the patients in the two groups on the first, second, third and fourth days after the intervention (p>0.05 ). There was no significant difference between the level of consciousness (according to GCS criteria), respiratory index (PAO2/FIO2) and PEEP of patients in the two study groups within 1 to 2 days after the intervention (p>0.05). There was a significant difference between the level of consciousness (based on GCS criteria), respiratory index (PAO2/FIO2) and PEEP of patients in the two study groups within 3 to 4 days after the intervention (p<0.05). There was no significant difference between the duration of hospitalization in the ICU, the time required for mechanical ventilation and the mortality rate of the patients in the two groups (p>0.05). Conclusion: It seems that N-acetylcysteine has a positive effect on the treatment of acute respiratory distress syndrome in mechanically ventilated patients admitted to the intensive care unit.

The Role of Nutrition in COVID-19 Susceptibility and Severity of Disease: A Systematic Review

BACKGROUND

Many nutrients have powerful immunomodulatory actions with the potential to alter susceptibility to coronavirus disease 2019 (COVID-19) infection, progression to symptoms, likelihood of severe disease, and survival.

OBJECTIVE

The aim was to review the latest evidence on how malnutrition across all its forms (under- and overnutrition and micronutrient status) may influence both susceptibility to, and progression of, COVID-19.

METHODS

We synthesized information on 13 nutrition-related components and their potential interactions with COVID-19: overweight, obesity, and diabetes; protein-energy malnutrition; anemia; vitamins A, C, D, and E; PUFAs; iron; selenium; zinc; antioxidants; and nutritional support. For each section we provide: 1) a landscape review of pertinent material; 2) a systematic search of the literature in PubMed and EMBASE databases, including a wide range of preprint servers; and 3) a screen of 6 clinical trial registries. All original research was considered, without restriction to study design, and included if it covered: 1) severe acute respiratory syndrome coronavirus (CoV) 2 (SARS-CoV-2), Middle East respiratory syndrome CoV (MERS-CoV), or SARS-CoV viruses and 2) disease susceptibility or 3) disease progression, and 4) the nutritional component of interest. Searches took place between 16 May and 11 August 2020.

RESULTS

Across the 13 searches, 2732 articles from PubMed and EMBASE, 4164 articles from the preprint servers, and 433 trials were returned. In the final narrative synthesis, we include 22 published articles, 38 preprint articles, and 79 trials.

CONCLUSIONS

Currently there is limited evidence that high-dose supplements of micronutrients will either prevent severe disease or speed up recovery. However, results of clinical trials are eagerly awaited. Given the known impacts of all forms of malnutrition on the immune system, public health strategies to reduce micronutrient deficiencies and undernutrition remain of critical importance. Furthermore, there is strong evidence that prevention of obesity and type 2 diabetes will reduce the risk of serious COVID-19 outcomes. This review is registered at PROSPERO as CRD42020186194.

N-acetyl-cysteine reduces the risk for mechanical ventilation and mortality in patients with COVID-19 pneumonia: a two-center retrospective cohort study

BACKGROUND

N-acetyl-cysteine (NAC) has been previously shown to exert beneficial effects in diverse respiratory diseases, through antioxidant and anti-inflammatory actions. Our aim was to evaluate NAC potential impact in hospitalised patients with COVID-19 pneumonia, in terms of progression to severe respiratory failure (SRF) and mortality.

PATIENTS AND METHODS

This retrospective, two-centre cohort study included consecutive patients hospitalised with moderate or severe COVID-19 pneumonia. Patients who received standard of care were compared with patients who additionally received NAC 600 mg bid orally for 14 days. Patients' clinical course was recorded regarding (i) the development of SRF (PO₂/FiO₂ <150) requiring mechanical ventilation support and (ii) mortality at 14 and 28 days.

RESULTS

A total of 82 patients were included, 42 in the NAC group and 40 in the control group. Treatment with oral NAC led to significantly lower rates of progression to SRF as compared to the control group (p < .01). Patients in the NAC group presented significantly lower 14- and 28-day mortality as compared to controls (p < .001 and p < .01 respectively). NAC treatment significantly reduced 14- and 28-day mortality in patients with severe disease (p < .001, respectively). NAC improved over time the PO2/FiO2 ratio and decreased the white blood cell, CRP, D-dimers and LDH levels. In the multivariable logistic regression analysis, non-severe illness and NAC administration were independent predictors of 28-days survival.

CONCLUSION

Oral NAC administration (1200 mg/d) in patients with COVID-19 pneumonia reduces the risk for mechanical ventilation and mortality. Our findings need to be confirmed by properly designed prospective clinical trials.

A pilot study on intravenous N-Acetylcysteine treatment in patients with mild-to-moderate COVID19-associated acute respiratory distress syndrome

Background

We designed this single-centre clinical trial to assess the potential benefits of N-Acetylcysteine (NAC) in patients with COVID19-associated acute respiratory distress syndrome (ARDS).

Methods

Ninety-two patients with mild-to-moderate COVID19-associated ARDS were allocated to the placebo (45-cases) or NAC groups (47-cases). Besides standard-of-care treatment, the patients received either intravenous NAC at a dose of 40 mg/kg/day or the placebo for three consecutive days. The efficacy outcomes were overall mortality over 28-day, clinical status on day 28, based on the WHO Master Protocol, the proportion of patients requiring mechanical ventilation, changes in ARDS-severity (based on the PaO₂/FiO₂ ratio), and Sequential Organ Failure Assessment (SOFA) scores 48 and 96 h after intervention,

Results

No differences were found in the 28-day mortality rate between the two groups (25.5% vs. 31.1% in the NAC and placebo groups, respectively). Although the distribution of the clinical status at day 28 shifted towards better outcomes in the NAC-treated group, it did not reach a statistical significance level (p value = 0.83). Similar results were achieved in terms of the proportion of patients who required invasive ventilator support (38.3% vs. 44.4%), the number of ventilator-free days (17.4 vs. 16.6), and median time of ICU and hospital stay. Results regarding the change in PaO₂/FiO₂ ratio and SOFA scores also showed no significant differences between the groups.

Conclusions

Our pilot study did not support the potential benefits of intravenous NAC in treating patients with COVID-19-associated ARDS. More studies are needed to determine which COVID-19 patients benefit from the NAC administration.

Trial registration

The trial was registered at Clinicaltrials.gov (identifier code: IRCT20120215009014N355). Registration date: 2020-05-18.

The Association of Respiratory Viruses with Oxidative Stress and Antioxidants. Implications for the COVID-19 Pandemic

The spread of a new strain of coronavirus, SARS-CoV-2, a pandemic, poses a serious health problem for all humanity. Compared with the previous outbreaks of coronavirus infection in 2002 and 2012, COVID-19 infection has high rates of lethality, contagiousness, and comorbidity. The effective methods of prevention and treatment are extremely limited. Oxidative stress is actively involved in the mechanisms of initiation and maintenance of violations of homeostatic reactions in respiratory viral infections. It is important to stop systemic inflammation aimed at "extinguishing" the cytokine "storm", caused by the production of reactive oxygen species. Antioxidant defense medications, such as vitamin C, N-acetylcysteine, melatonin, quercetin, glutathione, astaxanthin, polyphenols, fat-soluble vitamins, and polyunsaturated fatty acids have proven well in experimental and clinical studies of influenza, pneumonia, and other respiratory disorders. The use of medications with antioxidant activity could be justified and most probably would increase the effectiveness of the fight against new coronavirus.

COVID-19 Sepsis: Pathogenesis and Endothelial Molecular Mechanisms Based on "Two-Path Unifying Theory" of Hemostasis and Endotheliopathy-Associated Vascular Microthrombotic Disease, and Proposed Therapeutic Approach with Antimicrothrombotic Therapy

COVID-19 sepsis is characterized by acute respiratory distress syndrome (ARDS) as a consequence of pulmonary tropism of the virus and endothelial heterogeneity of the host. ARDS is a phenotype among patients with multiorgan dysfunction syndrome (MODS) due to disseminated vascular microthrombotic disease (VMTD). In response to the viral septicemia, the host activates the complement system which produces terminal complement complex C5b-9 to neutralize pathogen. C5b-9 causes pore formation on the membrane of host endothelial cells (ECs) if CD59 is underexpressed. Also, viral S protein attraction to endothelial ACE2 receptor damages ECs. Both affect ECs and provoke endotheliopathy. Disseminated endotheliopathy activates two molecular pathways: inflammatory and microthrombotic. The former releases inflammatory cytokines from ECs, which lead to inflammation. The latter initiates endothelial exocytosis of unusually large von Willebrand factor (ULVWF) multimers and FVIII from Weibel-Palade bodies. If ADAMTS13 is insufficient, ULVWF multimers activate intravascular hemostasis of ULVWF path. In activated ULVWF path, ULVWF multimers anchored to damaged endothelial cells recruit circulating platelets and trigger microthrombogenesis. This process produces "microthrombi strings" composed of platelet-ULVWF complexes, leading to endotheliopathy-associated VMTD (EA-VMTD). In COVID-19, microthrombosis initially affects the lungs per tropism causing ARDS, but EA-VMTD may orchestrate more complex clinical phenotypes, including thrombotic thrombocytopenic purpura (TTP)-like syndrome, hepatic coagulopathy, MODS and combined micro-macrothrombotic syndrome. In this pandemic, ARDS and pulmonary thromboembolism (PTE) have often coexisted. The analysis based on two hemostatic theories supports ARDS caused by activated ULVWF path is EA-VMTD and PTE caused by activated ULVWF and TF paths is macrothrombosis. The thrombotic disorder of COVID-19 sepsis is consistent with the notion that ARDS is virus-induced disseminated EA-VMTD and PTE is in-hospital vascular injury-related macrothrombosis which is not directly  related to viral pathogenesis. The pathogenesis-based therapeutic approach is discussed for the treatment of EA-VMTD with antimicrothrombotic regimen and the potential need of anticoagulation therapy for coinciding macrothrombosis in comprehensive COVID-19 care.

Protective action of N-acetyl-L-cysteine associated with a polyvalent antivenom on the envenomation induced by Lachesis muta muta (South American bushmaster) in rats

In this study, we examined the potential use of N-acetyl-L-cysteine (NAC) in association with a polyvalent antivenom and as stand-alone therapy to reduce the acute local and systemic effects induced by Lachesis muta muta venom in rats. Male Wistar rats (300-350 g) were exposed to L. m. muta venom (1.5 mg/kg - i.m.) and subsequently treated with anti-Bothrops/Lachesis serum (antivenom:venom ratio 1:3 'v/w' - i.p.) and NAC (150 mg/kg - i.p.) separately or in association; the animals were monitored for 120 min to assess changes in temperature, locomotor activity, local oedema formation and the prevalence of haemorrhaging. After this time, animals were anesthetized in order to collect blood samples through intracardiac puncture and then euthanized for collecting tissue samples; the hematological-biochemical and histopathological analyses were performed through conventional methods. L. m. muta venom produced pronounced local oedema, subcutaneous haemorrhage and myonecrosis, with both antivenom and NAC successfully reducing the extent of the myonecrotic lesion when individually administered; their association also prevented the occurrence of subcutaneous haemorrhage. Venom-induced creatine kinase (CK) release was significantly prevented by NAC alone or in combination with antivenom; NAC alone failed to reduce the release of hepatotoxic (alanine aminotransferase) and nephrotoxic (creatinine) serum biomarkers induced by L. m. muta venom. Venom induced significant increase of leucocytes which was also associated with an increase of neutrophils, eosinophils and monocytes; antivenom and NAC partially reduced these alterations, with NAC alone significantly preventing the increase of eosinophils whereas neither NAC or antivenom prevented the increase in monocytes. Venom did not induce changes in the erythrogram parameters. In the absence of a suitable antivenom, NAC has the potential to reduce a number of local and systemic effects caused by L. m. muta venom.

Preventing the development of severe COVID-19 by modifying immunothrombosis

BACKGROUND

COVID-19-associated acute respiratory distress syndrome (ARDS) is associated with significant morbidity and high levels of mortality. This paper describes the processes involved in the pathophysiology of COVID-19 from the initial infection and subsequent destruction of type II alveolar epithelial cells by SARS-CoV-2 and culminating in the development of ARDS.

MAIN BODY

The activation of alveolar cells and alveolar macrophages leads to the release of large quantities of proinflammatory cytokines and chemokines and their translocation into the pulmonary vasculature. The presence of these inflammatory mediators in the vascular compartment leads to the activation of vascular endothelial cells platelets and neutrophils and the subsequent formation of platelet neutrophil complexes. These complexes in concert with activated endothelial cells interact to create a state of immunothrombosis. The consequence of immunothrombosis include hypercoagulation, accelerating inflammation, fibrin deposition, migration of neutrophil extracellular traps (NETs) producing neutrophils into the alveolar apace, activation of the NLRP3 inflammazome, increased alveolar macrophage destruction and massive tissue damage by pyroptosis and necroptosis Therapeutic combinations aimed at ameliorating immunothrombosis and preventing the development of severe COVID-19 are discussed in detail.

Actualización de la Declaración de consenso en medicina critica para la atención multidisciplinaria del paciente con sospecha o confirmación diagnóstica de COVID-19

Antecedentes y objetivos

La enfermedad por coronavirus de 2019 (COVID-19) es una enfermedad ocasionada por el nuevo coronavirus del síndrome respiratorio agudo grave (SARS-CoV-2). Se identificó por primera vez en diciembre de 2019 en la ciudad de Wuhan, en los meses siguientes se expandió rápidamente a todos los continentes y la Organización Mundial de la Salud (OMS) la reconoció como una pandemia global el 11 de marzo de 2020. La mayoría de los individuos son asintomáticos pero una baja proporción ingresan a cuidados intensivos con una alta morbimortalidad. Este consenso tiene como objetivo actualizar la declaratoria inicial emitida por la Asociación Colombiana de Medicina Crítica (AMCI) para el manejo del paciente críticamente enfermo con COVID-19, dentro de las áreas críticas de las instituciones de salud.

Métodos

Este estudio utilizó dos técnicas de consenso formal para construir las recomendaciones finales: Delphi modificada y grupos nominales. Se construyeron preguntas por la estrategia PICO. 10 grupos nominales desarrollaron recomendaciones para cada unidad temática. El producto del consenso fue evaluado y calificado en una ronda Delphi y se discutió de forma virtual por los relatores de cada núcleo y los representantes de sociedades médicas científicas afines al manejo del paciente con COVID-19.

Resultados

80 expertos nacionales participaron en la actualización del consenso AMCI, especialistas en Medicina Critica y Cuidados Intensivos, Nefrología, Neurología, Neumología, bioeticistas, Medicina interna, Anestesia, Cirugía General, Cirugía de cabeza y cuello, Cuidados Paliativos, Enfermeras Especialistas en Medicina crítica, Terapeutas respiratorias especialistas en medicina crítica y Fisioterapia, con experiencia clínica en la atención del paciente críticamente enfermo. La declaratoria emite recomendaciones en los ámbitos más relevantes para la atención en salud de los casos de COVID-19, al interior de las unidades de cuidados intensivos, en el contexto nacional de Colombia.

Conclusiones

Un grupo significativo multidisciplinario de profesionales expertos en medicina crítica emiten, mediante técnicas de consenso formal, recomendaciones sobre la mejor práctica para la atención del paciente críticamente enfermo con COVID-19. Las recomendaciones deben ser adaptadas a las condiciones específicas, administrativas y estructurales de las distintas unidades de cuidados intensivos del país.

N-acetylcysteine and coronavirus disease 2019: May it work as a beneficial preventive and adjuvant therapy? A comprehensive review study

BACKGROUND

Coronaviruses are major pathogens of respiratory system causing different disorders, including the common cold, Middle East respiratory syndrome, and severe acute respiratory syndrome. Today's global pandemic coronavirus disease 2019 (COVID-19) has high mortality rate, with an approximate of 20% in some studies, and is 30-60 times more fatal than the common annual influenza, However, there is still no gold standard treatment for it. N-acetylcysteine (NAC) is a well-known multi-potential drug with hypothetically probable acceptable effect on COVID-related consequences, which we completely focused in this comprehensive review.

MATERIALS AND METHODS

PubMed, Scopus, Science Direct, and Google Scholar have been searched. Study eligibility criteria: efficacy of NAC in various subclasses of pathogenic events which may occur during COVID-19 infection. Efficacy of NAC for managing inflammatory or any symptoms similar to symptoms of COVID-19 was reviewed and symptom improvements were assessed.

RESULTS

Randomized clinical trials introduced NAC as an antioxidant glutathione analog and detoxifying agent promoted for different medical conditions and pulmonary disorders to alleviate influenza and reduce mortality by 50% in influenza-infected animals. The beneficial effects of NAC on viral disorders, including Epstein-Barr virus, HIV and hepatitis, and well-known vital organ damages were also exist and reported.

CONCLUSION

We classified the probable effects of NAC as oxidative-regulatory and apoptotic-regulatory roles, antiviral activities, anti-inflammatory roles, preventive and therapeutic roles in lung disorders and better oxygenation functions, supportive roles in intensive care unit admitted patients and in sepsis, positive role in other comorbidities and nonpulmonary end-organ damages or failures and even in primary COVID-associated cutaneous manifestations. Based on different beneficial effects of NAC, it could be administered as a potential adjuvant therapy for COVID-19 considering patient status, contraindications, and possible drug-related adverse events.

Long non-coding RNA SNHG5 suppresses the development of acute respiratory distress syndrome by targeting miR-205/COMMD1 axis

Previous studies have reported the important roles of long non-coding RNAs (lncRNAs) in acute respiratory distress syndrome (ARDS). Here, we focus on the role and regulatory mechanism of lncRNA SNHG5 in ARDS. LPS was used to induce mice to establish ARDS model in vivo and to induce A549 cells to establish ARDS model in vitro. qRT-PCR was performed to determine the expressions of SNHG5, miR-205, and inflammatory cytokines. MTT assay was applied to detect cell viability. Dual-luciferase reporter (DLR) assay was performed to test the interactions among SNHG5, miR-205 and COMMD1. Western blot was used to detect the protein expression of COMMD1. Lung injury was evaluated by evaluating the score of lung injury, lung wet/dry weight ratio, and myeloperoxidase (MPO) activity. SNHG5 was downregulated, while miR-205 was upregulated in the serum of ARDS patients and lung tissues of LPS-induced mice. Upregulation of SNHG5 or down-regulation of miR-205 inhibited inflammation and promoted the viability of LPS-induced A549 cells. SNHG5 alleviated the lung injury of ARDS mice. MiR-205 was a target of SNHG5 and inversely correlated with SNHG5. COMMD1 was targeted by miR-205, and was positively regulated by SNHG5. MiR-205 mimics or sh-COMMD1 reversed the promoting effect of SNHG5 on cell viability and the suppressing effect of SNHG5 on inflammation in cellular model of ARDS. Meantime, miR-205 mimics reversed the relieving effect of SNHG5 on lung injury in mouse model of ARDS. SNHG5 acted as a sponge for miR-205 to ameliorate LPS-induced ARDS by regulating COMMD1.

Disease-modifying treatment of chemical threat agent-induced acute lung injury

Acute respiratory distress syndrome (ARDS) is a highly morbid lung pathology induced by exposure to chemical warfare agents, including vesicants, phosgene, chlorine, and ricin. In this review, we describe the pathology associated with the development of ARDS in humans and experimental models of acute lung injury following animal exposure to these high-priority threat agents. Potential future approaches to disease-modifying treatment used in preclinical animal studies, including antioxidants, anti-inflammatories, biologics, and mesenchymal stem cells, are also described. As respiratory pathologies, including ARDS, are the major cause of morbidity and mortality following exposure to chemical threat agents, understanding mechanisms of disease pathogenesis is key to the development of efficacious therapeutics beyond the primary intervention principle, which remains mechanical ventilation.

Targeting Neutrophils to Treat Acute Respiratory Distress Syndrome in Coronavirus Disease

This review describes targeting neutrophils as a potential therapeutic strategy for acute respiratory distress syndrome (ARDS) associated with coronavirus disease 2019 (COVID-19), a pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Neutrophil counts are significantly elevated in patients with COVID-19 and significantly correlated with disease severity. The neutrophil-to-lymphocyte ratio can serve as a clinical marker for predicting fatal complications related to ARDS in patients with COVID-19. Neutrophil-associated inflammation plays a critical pathogenic role in ARDS. The effector functions of neutrophils, acting as respiratory burst oxidants, granule proteases, and neutrophil extracellular traps, are linked to the pathogenesis of ARDS. Hence, neutrophils can not only be used as pathogenic markers but also as candidate drug targets for COVID-19 associated ARDS.

N-Acetylcysteine: A potential therapeutic agent for SARS-CoV-2

COVID-19, a respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to spread across the globe. Predisposing factors such as age, diabetes, cardiovascular disease, and lowered immune function increase the risk of disease severity. T cell exhaustion, high viral load, and high levels of TNF-ɑ, IL1β, IL6, IL10 have been associated with severe SARS-CoV-2. Cytokine and antigen overstimulation are potentially responsible for poor humoral response to the virus. Lower cellular redox status, which leads to pro-inflammatory states mediated by TNF-ɑ is also potentially implicated. In vivo, in vitro, and human clinical trials have demonstrated N-acetylcysteine (NAC) as an effective method of improving redox status, especially when under oxidative stress. In human clinical trials, NAC has been used to replenish glutathione stores and increase the proliferative response of T cells. NAC has also been shown to inhibit the NLRP3 inflammasome pathway (IL1β and IL18) in vitro, and decrease plasma TNF-ɑ in human clinical trials. Mediation of the viral load could occur through NAC's ability to increase cellular redox status via maximizing the rate limiting step of glutathione synthesis, and thereby potentially decreasing the effects of virally induced oxidative stress and cell death. We hypothesize that NAC could act as a potential therapeutic agent in the treatment of COVID-19 through a variety of potential mechanisms, including increasing glutathione, improving T cell response, and modulating inflammation. In this article, we present evidence to support the use of NAC as a potential therapeutic agent in the treatment of COVID-19.

COVID-19: oxidative stress and the relevance of antioxidant therapy

The emergence of viral respiratory pathogens with high pandemic potential, such as the SARS-CoV-2, poses a serious public health problem, with a very limited arsenal of effective tools and techniques to prevent and treat a new pandemic infection. The literature on the involvement of reactive oxygen species in the pathogenesis of coronavirus infections and the potential for antioxidant therapy was reviewed. Because of available evidence on the involvement of oxidative stress in the mechanisms of initiation and maintenance of homeostasis disorders in SARS-CoV-2, approaches combining reduction of ROS synthesis, inhibition of virus replication, anti-inflammatory action, reduction of hypoxia, and reduction of the toxic effects of drug therapy may be very effective. The hypothesis of the expediency of treating systemic inflammation aimed at "quenching" the cytokine "storm", caused largely by the production of reactive oxygen species, seems essential. In this connection, it is pathophysiologically justified to use for prophylactic and therapeutic purposes antioxidant drugs, which have proven themselves on the example of other viral respiratory infections. Thus, the high activity of preparations of vitamin C, N-acetylcysteine, melatonin, quercetin, glutathione, astaxanthin, polyphenols, polyunsaturated fatty acids, etc. was noted. In addition, these drugs effectively protect the vascular wall, which has been proven for a number of cardiovascular diseases and that can be effective in developing with COVID-19 vasculitis. There is a more pronounced combined effect of these drugs, which is already used in treatment protocols for patients with SARS-CoV-2. Special attention should also be paid to the use of antioxidant drugs as a means to reduce the toxic manifestations of antiviral therapy. Thus, the use of drugs with antioxidant activity can be justified and will certainly improve the effectiveness of the fight against the pandemic of new coronavirus infection.

Airway Hygiene in COVID-19 Pneumonia: Treatment Responses of 3 Critically Ill Cruise Ship Employees

BACKGROUND COVID-19, the disease entity caused by the novel severe acute respiratory coronavirus 2 (SARS-CoV-2), continues to pose a major therapeutic challenge for clinicians. At present, an effective treatment regimen and vaccination has not been established. Many patients develop severe symptoms requiring endotracheal intubation and a prolonged stay in the Intensive Care Unit (ICU). In early postmortem examinations of COVID-19 patients, profuse viscous secretions were observed throughout the respiratory tract. Thus, oxygen supplementation without aggressive pulmonary hygiene management may be suboptimal. In the present case series, pulmonary hygiene management encompassed mucolytics, bronchodilators, and tracheal suctioning. We report 3 severe cases of COVID-19 pneumonia in cruise ship employees who were admitted to the ICU and responded to supportive mechanical ventilation and pulmonary hygiene management. CASE REPORT Three cruise ship employees with COVID-19 underwent endotracheal intubation and were admitted to the ICU for acute hypoxemic respiratory failure. Initial chest X-rays suggested multifocal pneumonia with superimposed acute respiratory distress syndrome (ARDS). A regimen of hydroxychloroquine, azithromycin, and dexamethasone was initiated on admission in all cases. Additionally, medications used for pulmonary hygiene were administered through a metered-dose inhaler (MDI) in line with the ventilator circuit. Endotracheal suctioning was performed prior to medication administration. The duration from endotracheal intubation to extubation ranged from 9 to 24 days. All 3 patients reached 30-day survival. CONCLUSIONS The cases reported highlight the importance of the use of airway hygiene with mucolytics, bronchodilators, and tracheal suctioning for patients with COVID-19 pneumonia requiring ventilatory support.

Reactive oxygen species as an initiator of toxic innate immune responses in retort to SARS-CoV-2 in an ageing population, consider N-acetylcysteine as early therapeutic intervention

During the current COVID-19 pandemic, a need for evaluation of already available drugs for treatment of the disease is crucial. Hereby, based on literature review from the current pandemic and previous outbreaks with corona viruses we analyze the impact of the virus infection on cell stress responses and redox balance. High levels of mortality are noticed in elderly individuals infected with SARS-CoV2 and during the previous SARS-CoV1 outbreak. Elderly individuals maintain a chronic low level of inflammation which is associated with oxidative stress and inflammatory cytokine production, a condition that increases the severity of viral infections in this population. Coronavirus infections can lead to alterations of redox balance in infected cells through modulation of NAD + biosynthesis, PARP function along with altering proteasome and mitochondrial function in the cell thereby leading to enhanced cell stress responses which further exacerbate inflammation. ROS production can increase IL-6 production and lipid peroxidation resulting in cell damage. Therefore, early treatment with anti-oxidants such as NAC during COVID-19 can be a way to bypass the excessive inflammation and cell damage that lead to severe infection, thus early NAC as intervention should be evaluated in a clinical trial setting.

The many faces of the anti-COVID immune response

The novel 2019 strain of coronavirus is a source of profound morbidity and mortality worldwide. Compared with recent viral outbreaks, COVID-19 infection has a relatively high mortality rate, the reasons for which are not entirely clear. Furthermore, treatment options for COVID-19 infection are currently limited. In this Perspective, we explore the contributions of the innate and adaptive immune systems to both viral control as well as toxicity during COVID-19 infections and offer suggestions to both understand and therapeutically modulate anti-COVID immunity.

The many faces of the anti-COVID immune response

The novel 2019 strain of coronavirus is a source of profound morbidity and mortality worldwide. Compared with recent viral outbreaks, COVID-19 infection has a relatively high mortality rate, the reasons for which are not entirely clear. Furthermore, treatment options for COVID-19 infection are currently limited. In this Perspective, we explore the contributions of the innate and adaptive immune systems to both viral control as well as toxicity during COVID-19 infections and offer suggestions to both understand and therapeutically modulate anti-COVID immunity.

Long non-coding RNA MALAT1 exacerbates acute respiratory distress syndrome by upregulating ICAM-1 expression via microRNA-150-5p downregulation

Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury in which severe inflammatory responses induce cell apoptosis, necrosis, and fibrosis. This study investigated the role of lung adenocarcinoma transcript 1 (MALAT1) in ARDS and the underlying mechanism involved. The expression of MALAT1, microRNA-150-5p (miR-150-5p), and intercellular adhesion molecule-1 (ICAM-1) was determined in ARDS patients and lipopolysaccharide (LPS)-treated human pulmonary microvascular endothelial cells (HPMECs). Next, the interactions among MALAT1, miR-150-5p, and ICAM-1 were explored. Gain- or loss-of-function experiments in HPMECs were employed to determine cell apoptosis and inflammation. Furthermore, a mouse xenograft model of ARDS was established in order to verify the function of MALAT1 in vivo. MALAT1 and ICAM-1 were upregulated, while miR-150-5p was downregulated in both ARDS patients and LPS-treated HPMECs. MALAT1 upregulated ICAM-1 expression by competitively binding to miR-150-5p. MALAT1 silencing or miR-150-5p overexpression was shown to suppress HPMEC apoptosis, decrease the expressions of pro-inflammatory cytokines (IL-6, IL-1β and TNF-α) and E-selectin in HPMECs, as well as alleviated lung injury in nude mice. These findings demonstrated that MALAT1 silencing can potentially suppress HPMEC apoptosis and alleviate lung injury in ARDS via miR-150-5p-targeted ICAM-1, suggestive of a novel therapeutic target for ARDS.

Acute Respiratory Distress Syndrome as an Organ Phenotype of Vascular Microthrombotic Disease: Based on Hemostatic Theory and Endothelial Molecular Pathogenesis

Acute respiratory distress syndrome (ARDS) is a life-threatening noncardiogenic circulatory disorder of the lungs associated with critical illnesses such as sepsis, trauma, and immune and collagen vascular disease. Its mortality rate is marginally improved with the best supportive care. The demise occurs due to progressive pulmonary hypoxia and multi-organ dysfunction syndrome (MODS) with severe inflammation. Complement activation is a part of immune response against pathogen or insult in which membrane attack complex (MAC) is formed and eliminates microbes. If complement regulatory protein such as endothelial CD59 is underexpressed, MAC may also cause pulmonary vascular injury to the innocent bystander endothelial cell of host and provokes endotheliopathy that causes inflammation and pulmonary vascular microthrombosis, leading to ARDS. Its pathogenesis is based on a novel "two-path unifying theory" of hemostasis and "two-activation theory of the endothelium" promoting molecular pathogenesis. Endotheliopathy activates two independent molecular pathways: inflammatory and microthrombotic. The former triggers the release inflammatory cytokines and the latter promotes exocytosis of unusually large von Willebrand factor multimers (ULVWF) and platelet activation. Inflammatory pathway initiates inflammation, but microthrombotic pathway more seriously produces "microthrombi strings" composed of platelet-ULVWF complexes, which become anchored on the injured endothelial cells, and causes disseminated intravascular microthrombosis (DIT). DIT is a hemostatic disease due to lone activation of ULVWF path without activated tissue factor path. It leads to endotheliopathy-associated vascular microthrombotic disease (EA-VMTD), which orchestrates consumptive thrombocytopenia, microangiopathic hemolytic anemia, and MODS. Thrombotic thrombocytopenic purpura (TTP)-like syndrome is the hematologic phenotype of EA-VMTD. ARDS is one of organ phenotypes among MODS associated with TTP-like syndrome. The most effective treatment of ARDS can be achieved by counteracting the activated microthrombotic pathway based on two novel hemostatic theories.

Resveratrol decreases CD45+ CD206- subtype macrophages in LPS-induced murine acute lung injury by SOCS3 signalling pathway

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) are life-threatening condition in critically ill patients. Resveratrol (Res), a natural polyphenol, has therapeutic effect in animal model with ALI; however, whether Res attenuates ALI through modulation of macrophage phenotypes in the animal model remains unknown. We in this study treated LPS-induced murine ALI with 30 mg/kg Res and observed significantly reduced severity of ALI in the Res-treated mice 48 hours after Res treatment. Neutrophil infiltrates were significantly reduced, accompanied with lower infiltration of CD45⁺ Siglec F^- phenotype macrophages, but higher population of CD45⁺ Siglec F⁺ and CD45⁺ CD206⁺ alternatively activated macrophages (M2 cells) in the Res-treated mice with ALI. In addition, the expression of IL-1beta and CXCL15 cytokines was suppressed in the treated mice. However, Res treatment in mice with myeloid cell-restricted SOCS3 deficiency did not significantly attenuate ALI severity and failed to increase population of both CD45⁺ Siglec F⁺ and CD45⁺ CD206⁺ M2 subtype macrophages in the murine ALI. Further studies in wild-type macrophages revealed that Res treatment effectively reduced the expression of IL-6 and CXCL15, and increased the expression of arginase-1, SIRT1 and SOCS3. However, macrophages' lack of SOCS3 expression were resistant to the Res-induced suppression of IL-6 and CXCL15 in vitro. Thus, we conclude that Res suppressed CD45⁺ Siglec F^- and CD45⁺ CD206^- M1 subtype macrophages through SOCS3 signalling in the LPS-induced murine ALI.

Efficacy of 3% hypertonic saline in bronchiolitis: A meta-analysis

A meta-analysis was performed to analyze the efficacy of 3% hypertonic saline (HS) in bronchiolitis. Pubmed and MEDLINE databases were searched for relevant articles. A total of 2 authors selected the articles according to the inclusion criteria and then data were carefully extracted. Weighted mean difference (WMD) with 95% confidence interval (95% CI) values were used to pool continuous data, including length of stay and clinical severity score (CSS). Relative risk (RR) with 95% CI was calculated to determine the association between 3% HS and re-admission. The pooled data revealed that infants treated with 3% HS exhibited shorter durations of hospitalization compared with those treated with normal saline (NS; WMD=-0.43; 95% CI=-0.70, -0.15). Subgroup analysis examining the combination of HS or NS with additional medication demonstrated that 3% HS with epinephrine significantly decreased the length of hospital stay, with a WMD=-0.62 (95% CI=-0.90, -0.33). The results indicated a lower CSS score in the 3% HS group compared with the NS group (SMD=-0.80; 95% CI=-1.06, -0.54). The pooled outcome indicated a beneficial effect of 3% HS on decreasing re-admission rates compared with NS (RR=0.93; 95% CI=0.70, 1.23). No potential publication bias was observed (Begg's, P=0.133; Egger's, P=0.576). In conclusion, 3% HS was demonstrated to be a more successful therapy compared with NS for infants with bronchiolitis.

Pharmacological agents for adults with acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a life-threatening condition caused by direct or indirect injury to the lungs. Despite improvements in clinical management (for example, lung protection strategies), mortality in this patient group is at approximately 40%. This is an update of a previous version of this review, last published in 2004.

OBJECTIVES

To evaluate the effectiveness of pharmacological agents in adults with ARDS on mortality, mechanical ventilation, and fitness to return to work at 12 months.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and CINAHL on 10 December 2018. We searched clinical trials registers and grey literature, and handsearched reference lists of included studies and related reviews.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing pharmacological agents with control (placebo or standard therapy) to treat adults with established ARDS. We excluded trials of nitric oxide, inhaled prostacyclins, partial liquid ventilation, neuromuscular blocking agents, fluid and nutritional interventions and medical oxygen. We excluded studies published earlier than 2000, because of changes to lung protection strategies for people with ARDS since this date.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, and assessed risks of bias. We assessed the certainty of evidence with GRADE.

MAIN RESULTS

We included 48 RCTs with 6299 participants who had ARDS; two included only participants with mild ARDS (also called acute lung injury). Most studies included causes of ARDS that were both direct and indirect injuries. We noted differences between studies, for example the time of administration or the size of dose, and because of unclear reporting we were uncertain whether all studies had used equivalent lung protection strategies.We included five types of agents as the primary comparisons in the review: corticosteroids, surfactants, N-acetylcysteine, statins, and beta-agonists. We included 15 additional agents (sivelestat, mesenchymal stem cells, ulinastatin, anisodimine, angiotensin-converting enzyme (ACE) inhibitor, recombinant human ACE2 (palifermin), AP301, granulocyte-macrophage colony stimulating factor (GM-CSF), levosimendan, prostacyclins, lisofylline, ketaconazole, nitroglycerins, L-2-oxothiazolidine-4-carboxylic acid (OTZ), and penehyclidine hydrochloride).We used GRADE to downgrade outcomes for imprecision (because of few studies and few participants), for study limitations (e.g. high risks of bias) and for inconsistency (e.g. differences between study data).Corticosteroids versus placebo or standard therapyCorticosteroids may reduce all-cause mortality within three months by 86 per 1000 patients (with as many as 161 fewer to 19 more deaths); however, the 95% confidence interval (CI) includes the possibility of both increased and reduced deaths (risk ratio (RR) 0.77, 95% CI 0.57 to 1.05; 6 studies, 574 participants; low-certainty evidence). Due to the very low-certainty evidence, we are uncertain whether corticosteroids make little or no difference to late all-cause mortality (later than three months) (RR 0.99, 95% CI 0.64 to 1.52; 1 study, 180 participants), or to the duration of mechanical ventilation (mean difference (MD) -4.30, 95% CI -9.72 to 1.12; 3 studies, 277 participants). We found that ventilator-free days up to day 28 (VFD) may be improved with corticosteroids (MD 4.09, 95% CI 1.74 to 6.44; 4 studies, 494 participants; low-certainty evidence). No studies reported adverse events leading to discontinuation of study medication, or fitness to return to work at 12 months (FTR).Surfactants versus placebo or standard therapyWe are uncertain whether surfactants make little or no difference to early mortality (RR 1.08, 95% CI 0.91 to 1.29; 9 studies, 1338 participants), or whether they reduce late all-cause mortality (RR 1.28, 95% CI 1.01 to 1.61; 1 study, 418 participants). Similarly, we are uncertain whether surfactants reduce the duration of mechanical ventilation (MD -2.50, 95% CI -4.95 to -0.05; 1 study, 16 participants), make little or no difference to VFD (MD -0.39, 95% CI -2.49 to 1.72; 2 studies, 344 participants), or to adverse events leading to discontinuation of study medication (RR 0.50, 95% CI 0.17 to 1.44; 2 studies, 88 participants). We are uncertain of these effects because we assessed them as very low-certainty. No studies reported FTR.N-aceytylcysteine versus placeboWe are uncertain whether N-acetylcysteine makes little or no difference to early mortality, because we assessed this as very low-certainty evidence (RR 0.64, 95% CI 0.32 to 1.30; 1 study, 36 participants). No studies reported late all-cause mortality, duration of mechanical ventilation, VFD, adverse events leading to study drug discontinuation, or FTR.Statins versus placeboStatins probably make little or no difference to early mortality (RR 0.99, 95% CI 0.78 to 1.26; 3 studies, 1344 participants; moderate-certainty evidence) or to VFD (MD 0.40, 95% CI -0.71 to 1.52; 3 studies, 1342 participants; moderate-certainty evidence). Statins may make little or no difference to duration of mechanical ventilation (MD 2.70, 95% CI -3.55 to 8.95; 1 study, 60 participants; low-certainty evidence). We could not include data for adverse events leading to study drug discontinuation in one study because it was unclearly reported. No studies reported late all-cause mortality or FTR.Beta-agonists versus placebo controlBeta-blockers probably slightly increase early mortality by 40 per 1000 patients (with as many as 119 more or 25 fewer deaths); however, the 95% CI includes the possibility of an increase as well as a reduction in mortality (RR 1.14, 95% CI 0.91 to 1.42; 3 studies, 646 participants; moderate-certainty evidence). Due to the very low-certainty evidence, we are uncertain whether beta-agonists increase VFD (MD -2.20, 95% CI -3.68 to -0.71; 3 studies, 646 participants), or make little or no difference to adverse events leading to study drug discontinuation (one study reported little or no difference between groups, and one study reported more events in the beta-agonist group). No studies reported late all-cause mortality, duration of mechanical ventilation, or FTR.

AUTHORS' CONCLUSIONS

We found insufficient evidence to determine with certainty whether corticosteroids, surfactants, N-acetylcysteine, statins, or beta-agonists were effective at reducing mortality in people with ARDS, or duration of mechanical ventilation, or increasing ventilator-free days. Three studies awaiting classification may alter the conclusions of this review. As the potential long-term consequences of ARDS are important to survivors, future research should incorporate a longer follow-up to measure the impacts on quality of life.

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.