Effect of sivelestat sodium in patients with acute lung injury or acute respiratory distress syndrome: a meta-analysis of randomized controlled trials

Rod-shaped Polymerized Salicylic Acid Particles Modulate Neutrophil Transendothelial Migration in Acute Inflammation

Neutrophilic inflammation is present in numerous high-mortality pathologies, including sepsis, deep vein thrombosis, and acute lung injury (ALI). Therefore, regulating neutrophil recruitment becomes an attractive therapeutic approach for neutrophil-mediated inflammation. Here, the impact of salicylic acid-based polymeric particles in regulating neutrophil recruitment in vivo and in vitro, particularly investigating the impact of neutrophil targeting via particle geometry-driven phagocytosis is explored. It is found that rod-shaped polymeric particles can improve neutrophil targeting in a murine ALI model, effectively preventing neutrophil infiltration into the mice's lungs compared to spherical particles of the same volume. It is demonstrated that the elongated nature of the polymeric carriers reduced neutrophils' transmigration ability across endothelial barriers in vivo and in vitro, contributing to their therapeutic effectiveness. These data represent initial work in developing non-spherical particle-mediated targeting of activated neutrophils for conditions affected by neutrophilic injury.

Targeting neutrophils for cancer therapy

Neutrophils are among the most abundant immune cell types in the tumour microenvironment and have been associated with poor outcomes across multiple cancer types. Yet despite mounting evidence of their role in tumour progression, therapeutic strategies targeting neutrophils have only recently gained attention and remain limited in scope. This is probably due to the increasing number of distinct neutrophil subtypes identified in cancer and the limited understanding of the mechanisms by which these subsets influence tumour progression and immune evasion. In this Review, we discuss the spectrum of neutrophil subtypes - including those with antitumour activity - and their potential to polarize towards tumour-suppressive phenotypes. We explore the molecular pathways and effector functions by which neutrophils modulate cancer progression, with an emphasis on identifying tractable therapeutic targets. Finally, we examine emerging clinical trials aimed at modulating neutrophil lineages and consider their implications for patient outcomes.

Advances in anti-inflammatory treatment of sepsis-associated acute respiratory distress syndrome

Sepsis is characterized by a dysregulated host response to infection, leading to organ dysfunction and associated with significant morbidity and mortality, posing a critical challenge to global public health. Among its complications, sepsis frequently causes acute respiratory distress syndrome (ARDS), which has a high incidence and mortality rate, particularly in intensive care units (ICUs). Currently, the management of sepsis-induced ARDS is largely limited to supportive care, as no specific pharmacological treatments are available. The progression of sepsis to ARDS is driven by severe inflammation and cytokine storms, highlighting the importance of anti-inflammatory therapies as a primary treatment focus. We summarize conventional drugs and emerging treatments targeting excessive inflammatory responses in sepsis-associated ARDS, reviewing progress in basic research and clinical trials. Additionally, we discuss current research challenges to propose future directions for anti-inflammatory treatments, aiming to develop highly effective drugs with better clinical translation potential.

Advances in acute respiratory distress syndrome: focusing on heterogeneity, pathophysiology, and therapeutic strategies

In recent years, the incidence of acute respiratory distress syndrome (ARDS) has been gradually increasing. Despite advances in supportive care, ARDS remains a significant cause of morbidity and mortality in critically ill patients. ARDS is characterized by acute hypoxaemic respiratory failure with diffuse pulmonary inflammation and bilateral edema due to excessive alveolocapillary permeability in patients with non-cardiogenic pulmonary diseases. Over the past seven decades, our understanding of the pathology and clinical characteristics of ARDS has evolved significantly, yet it remains an area of active research and discovery. ARDS is highly heterogeneous, including diverse pathological causes, clinical presentations, and treatment responses, presenting a significant challenge for clinicians and researchers. In this review, we comprehensively discuss the latest advancements in ARDS research, focusing on its heterogeneity, pathophysiological mechanisms, and emerging therapeutic approaches, such as cellular therapy, immunotherapy, and targeted therapy. Moreover, we also examine the pathological characteristics of COVID-19-related ARDS and discuss the corresponding therapeutic approaches. In the face of challenges posed by ARDS heterogeneity, recent advancements offer hope for improved patient outcomes. Further research is essential to translate these findings into effective clinical interventions and personalized treatment approaches for ARDS, ultimately leading to better outcomes for patients suffering from ARDS.

Efficacy of sivelestat in alleviating postoperative pulmonary injury in patients with acute aortic dissection undergoing total arch replacement: a retrospective cohort study

OBJECTIVE

Sivelestat may reduce postoperative pulmonary injury after total arch replacement (TAR). This study aimed to evaluate whether the preoperative PaO2/FiO2 (P/F) ratio affects the efficacy of sivelestat in reducing postoperative pulmonary injury in patients with acute aortic dissection (AAD) who underwent TAR using deep hypothermic circulatory arrest (DHCA).

METHODS

Data of patients with AAD who underwent TAR using DHCA in a tertiary hospital between February 1, 2022, and December 30, 2022, were retrospectively reviewed. The patients were divided into the sivelestat and control groups. Three subgroup analyses were performed based on the postoperative P/F ratio. The primary clinical outcomes were assessed to determine the efficacy and safety of sivelestat in managing postoperative pulmonary dysfunction in patients undergoing cardiopulmonary bypass.

RESULTS

A total of 187 patients were included, with 95 in the sivelestat group and 92 in the control group. No significant differences were found in the clinical variables between the two groups (all P > 0.05), except for some improvements in the inflammatory biomarker levels (including white blood cell count, neutrophil count, and C-reactive protein). Subgroup analysis revealed that sivelestat treatment significantly increased the P/F ratio on the 4th day and 3rd day after TAR in patients with mild lung injury (P = 0.02) and moderate lung injury (P = 0.03), respectively. Additionally, sivelestat reduced the levels of several postoperative inflammatory biomarkers in both subgroups.

CONCLUSIONS

Among patients with AAD with mild or moderate preoperative lung injury, defined by a low P/F ratio, sivelestat significantly improved the postoperative P/F ratio and attenuated inflammatory responses after TAR. These findings suggest an important avenue for further research.

The Protective Effects of Sivelestat Sodium on the Basis of Corticosteroid Therapy in Patients With Moderate-to-Severe Acute Respiratory Distress Syndrome

Objective: We aimed to evaluate the protective effects of sivelestat sodium on the basis of corticosteroid therapy in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). Methods: We retrospectively investigated 127 patients with confirmed moderate-to-severe ARDS treated in the intensive care unit (ICU) at Dazhou Central Hospital. Patients were divided into the control group (corticosteroids alone) and the combination therapy of steroids and sivelestat sodium (CTSSS) group according to the therapeutic interventions. The primary outcome was in-hospital mortality. And the baseline characteristics and laboratory findings of patients were collected for analysis. Results: The overall mortality rate in 127 patients was 48.8%. There was no statistically significant difference in in-hospital mortality between the CTSSS group and the control group (45.3% vs. 56.1%). In the subgroup of patients aged < 80 years or with an Acute Physiology and Chronic Health Evaluation (APACHE) II score < 30, CTSSS could reduce the risk of mortality (odds ratio [OR] = 0.41, 95% confidence interval [CI], 0.17-0.96, p=0.041; OR = 0.31, 95% CI, 0.13-0.77, p=0.012; respectively). Among patients aged 80 years or older, those with CTSSS exhibited a significantly elevated risk of mortality (OR = 13; 95% CI, 1.20-140.73; p=0.035). Conclusion: Compared with corticosteroids alone, CTSSS could improve oxygenation index, increase lymphocyte count, protect extrapulmonary organs and reduce in-hospital mortality rate in patients with moderate-to-severe ARDS in specific subgroups (age < 80 years or APACHE II score < 30). It might be advisable to avoid CTSSS in moderate-to-severe ARDS patients aged 80 years or older. Prospective studies involving larger sample sizes are needed to verify these findings.

Steroids and Immunomodulatory Therapies for Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is characterized by a dysregulated immune response to infection or injury. This framework has driven long-standing interest in immunomodulatory therapies as treatments for ARDS. In this narrative review, we first define what constitutes a dysregulated immune response in ARDS. In this context, we describe the rationale and available evidence for immunomodulatory therapies studied in randomized controlled trials of ARDS patients to date. Finally, we address factors that have contributed to the failure to develop therapies in the past and highlight current and future developments designed to address them.

Clinical utility of the neutrophil elastase inhibitor sivelestat for the treatment of ALI/ARDS patients with COVID-19

Background

Sivelestat, a neutrophil elastase inhibitor, is postulated to mitigate acute lung injury in patients following emergency surgery. However, its efficacy in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) induced by coronavirus disease 2019 (COVID-19) remains uncertain. This study aims to evaluate the pulmonary protective effects of sivelestat in COVID-19 patients with ALI/ARDS.

Methods

A retrospective study was conducted involving 2454 COVID-19 patients between October 5, 2022, and February 1, 2023. Of these, 102 patients received sivelestat (0.2 mg/kg/h), while 2352 age- and sex-matched controls were identified. Propensity score matching (PSM) analysis was used to match sivelestat and non-sivelestat subgroups in ratios of 1:1 and 1:3 for sensitivity analysis. The primary outcome was a composite of effective outcomes, including 30-day mortality. Secondary outcomes included changes in partial pressure of arterial oxygen (PaO2), the ratio of PaO2 to the fraction of inspired oxygen (PaO2/FiO2), and various cytokine levels. Safety evaluations included assessments of liver function, kidney function, and leukopenia.

Results

In the propensity score-matched analysis, the sivelestat group had a higher proportion of severe/critical patients (87.26 % vs. 51.02 %, P < 0.001), more ARDS patients (4.9 % vs. 0.43 %, P < 0.001), and more patients with interstitial lung disease (4.9 % vs. 1.49 %, P = 0.023), but fewer patients with stroke (17.65 % vs. 19.86 %, P < 0.001). Oxygen therapy rates were similar between the groups (79.41 % vs. 80.95 %, P = 0.9). The relative risk reduction in 30-day mortality was 88.45 % (95 % confidence interval [CI] 81.23%-93.21 %) for severe/critical COVID-19 patients treated with sivelestat. Sivelestat significantly decreased cytokine levels of interferon alpha (IFNα), interleukin-1 beta (IL-1β), and interleukin-2 (IL-2).In the sivelestat group, the mortality rate was significantly reduced with standard oxygenation and HFNC therapy(P < 0.05). The treatment with sivelestat did not increase side effects.

Conclusion

The administration of the neutrophil elastase inhibitor sivelestat may improve clinical outcomes in COVID-19 patients with ALI/ARDS. These findings suggest that sivelestat could be considered an effective treatment option to alleviate pulmonary inflammatory injury caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Sivelestat improves acute lung injury by inhibiting PI3K/AKT/mTOR signaling pathway

OBJECTIVE

To investigate the therapeutic effect and mechanism of sivelestat sodium on acute lung injury (AIL).

METHODS

A rat model for ALI/acute respiratory distress syndrome (ALI/ARDS) was established. Pathological examination of lung tissue was conducted to assess lung injury. Blood gas in the arteries was measured using a blood analyzer. Changes in PaO2, PaO2/FiO2, and lung wet/dry (W/D) weight ratio were carefully compared. ELISA assay was conducted to estimate cell adhesion and inflammation response. Finally, real-time reverse transcription polymerase chain reaction and western blotting assay was used to determine the activation of PI3K/AKT/mTOR pathway.

RESULTS

ARDS in vivo model was successfully constructed by LPS injection. Compared with the sham group, PaO2 and PaO2/FiO2 were significantly lower in the vehicle group, while the lung W/D ratio, the lung injury score, NE, VCAM-1, IL-8 andTNF-αwere significantly increased. After treatment with different doses of sivelestat sodium, we found PaO2, PaO2/FiO2 were prominently increased, while the lung W/D ratio, the lung injury score, NE, VCAM-1, IL-8, TNF-α levels were decreased in the dose-dependent manner. Meanwhile, compared with the vehicle group, the expression levels of Bax, PI3K, Akt and mTOR were significantly lower, and the expression of Bcl-2 was significantly higher after injection with sivelestat sodium.

CONCLUSION

Sivelestat sodium has an interventional effect on ALI in sepsis by inhibiting the PI3K/AKT/mTOR signalling pathway.

Sivelestat Inhibits Vascular Endothelial Injury Induced by Inflammatory Response and Improves the Prognosis of Hemorrhagic Fever with Renal Syndrome in Children: An Ambispective Cohort Study

Background

In Asia, Hanta virus (HTNV) results in severe hemorrhagic fever with renal syndrome (HFRS). The efficacy of sivelestat in treating children with HTNV-induced HFRS remains unclear.

Methods

An ambispective cohort study was performed on children diagnosed with HFRS and hospitalized at the Children's Hospital Affiliated to Xi'an Jiaotong University from August 2018 to 2023. Patients who received neutrophil elastin-inhibitor infusion between August 2019 and August 2023 were assigned to the sivelestat group, while patients who did not were assigned to the control group. The independent sample t test was used for inter-group analysis. The Chi-square test and Fisher's exact probability test were used for categorical variables. Spearman correlation test was used to evaluate the correlation between two sets of continuous variables. Kaplan-Meier survival curve and Log -Rank test was used to evaluate the difference in cumulative probability of survival between the two groups.

Results

No significant differences were observed between the two groups in gender, age, contact history, body mass index, HFRS severity, clinical indexes at admission. Compared to the control group, the sivelestat group exhibited a significant decrease in the interleukin-8 level at 48 h (28.5±3 vs 34.5±3.5) and 72 h (21.3±4.5 vs 31.5±5.6) (P<0.05), as well as the ICAM-1 level at 48 h (553±122 vs 784±187) and 72 h (452±130 vs 623±85) (P<0.05). The concentration of VCAM-1 in the sivelestat group exhibited a consistent downward trend. Moreover, the level of VCAM-1 was significantly lower than that in the control group at 24 h (1760±289 vs 2180±445), 48 h (1450±441 vs 1890±267), and 72 h (1149±338 vs 1500±396) (P<0.05). Kaplan-Meier curve analysis revealed a statistically significant difference in the cumulative probability of survival between two groups (P = 0.041). In the secondary outcomes, the sivelestat group demonstrated a decrease in the utilization rate of mechanical ventilation and continuous renal replacement therapy (CRRT).

Conclusion

Sivelestat may suppress neutrophil-mediated inflammatory response to reduce endothelial and organ damage, and improve clinical outcomes in children with severe hemorrhagic fever and renal syndrome.

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.

Neutrophil-Derived Proteases in Lung Inflammation: Old Players and New Prospects

Neutrophil-derived proteases are critical to the pathology of many inflammatory lung diseases, both chronic and acute. These abundant enzymes play roles in key neutrophil functions, such as neutrophil extracellular trap formation and reactive oxygen species release. They may also be released, inducing tissue damage and loss of tissue function. Historically, the neutrophil serine proteases (NSPs) have been the main subject of neutrophil protease research. Despite highly promising cell-based and animal model work, clinical trials involving the inhibition of NSPs have shown mixed results in lung disease patients. As such, the cutting edge of neutrophil-derived protease research has shifted to proteases that have had little-to-no research in neutrophils to date. These include the cysteine and serine cathepsins, the metzincins and the calpains, among others. This review aims to outline the previous work carried out on NSPs, including the shortcomings of some of the inhibitor-orientated clinical trials. Our growing understanding of other proteases involved in neutrophil function and neutrophilic lung inflammation will then be discussed. Additionally, the potential of targeting these more obscure neutrophil proteases will be highlighted, as they may represent new targets for inhibitor-based treatments of neutrophil-mediated lung inflammation.

Neutrophil Extracellular Traps and Respiratory Disease

Extracellular traps made by neutrophils (NETs) and other leukocytes such as macrophages and eosinophils have a key role in the initial immune response to infection but are highly inflammatory and may contribute to tissue damage. They are particularly relevant to lung disease, with the pulmonary anatomy facilitating their ability to fully extend into the airways/alveolar space. There has been a rapid expansion in the number of published studies demonstrating their role in a variety of important respiratory diseases including chronic obstructive pulmonary disease, cystic fibrosis, bronchiectasis, asthma, pneumonia, COVID-19, rhinosinusitis, interstitial lung disease and lung cancer. The expression of NETs and other traps is a specific process, and diagnostic tests need to differentiate them from other inflammatory pathways/causes of cell death that are also characterised by the presence of extracellular DNA. The specific targeting of this pathway by relevant therapeutics may have significant clinical benefit; however, current clinical trials/evidence are at a very early stage. This review will provide a broad overview of the role of NETs and their possible treatment in respiratory disease.

Safety, tolerability, pharmacokinetics and neutrophil elastase inhibitory effects of Sivelestat: A randomized, double-blind, placebo-controlled single- and multiple-dose escalation study in Chinese healthy subjects

BACKGROUND AND OBJECTIVE

Neutrophil elastase has been identified as a potential therapeutic target for acute lung injury or acute respiratory distress syndrome, and Sivelestat is a selective, reversible and competitive neutrophil elastase inhibitor. This study was designed to investigate the safety, tolerability, pharmacokinetics and neutrophil elastase inhibitory effects of Sivelestat in healthy Chinese subjects.

METHODS

A randomized, double-blind, placebo-controlled single- and multiple-dose escalation clinical trial was carried out. Briefly, healthy volunteers in twelve cohorts with 8 per cohort received 1.0-20.2 mg/kg/h Sivelestat or placebo in an intravenous infusion manner for two hours, and healthy volunteers in four cohorts received two hours intravenous infusion of 2.0-5.0 mg/kg/h Sivelestat or placebo with an interval of twelve hours for seven times. The safety and tolerability were evaluated and serial blood samples were collected for pharmacokinetics and neutrophil elastase inhibitory effects analysis at the specified time-point.

RESULTS

A total of 128 subjects were enrolled and all participants completed the study except one. Sivelestat exhibited satisfactory safety and tolerability up to 20.2 mg/kg/h in single-dose cohorts and 5.0 mg/kg/h in multiple-dose cohorts. Even so, more attention should be paid to the safety risks when using high doses. The Cmax and AUC of Sivelestat increased in a dose dependent manner, and Tmax was similar for different dose cohorts. In multiple-dose cohorts, the plasma concentrations reached steady state 48 h after first administration and the accumulation of Cmax and AUC was not obvious. Furthermore, the Cmin_ss of 5.0 mg/kg/h dose cohort could meet the needs of clinical treatment. For some reason, the pharmacodynamics data revealed that the inhibitory effect of Sivelestat on neutrophil elastase content in healthy subjects was inconclusive.

CONCLUSION

Sivelestat was safe and well tolerated with appropriate pharmacokinetic parameters, which provided support for more diverse dosing regimen in clinical application.

CLINICAL TRIAL REGISTRATION

www.chinadrugtrials.org.cn identifier is CTR20210072.

A GMR enzymatic assay for quantifying nuclease and peptidase activity

Hydrolytic enzymes play crucial roles in cellular processes, and dysregulation of their activities is implicated in various physiological and pathological conditions. These enzymes cleave substrates such as peptide bonds, phosphodiester bonds, glycosidic bonds, and other esters. Detecting aberrant hydrolase activity is vital for understanding disease mechanisms and developing targeted therapeutic interventions. This study introduces a novel approach to measuring hydrolase activity using giant magnetoresistive (GMR) spin valve sensors. These sensors change resistance in response to magnetic fields, and here, they are functionalized with specific substrates for hydrolases conjugated to magnetic nanoparticles (MNPs). When a hydrolase cleaves its substrate, the tethered magnetic nanoparticle detaches, causing a measurable shift in the sensor's resistance. This design translates hydrolase activity into a real-time, activity-dependent signal. The assay is simple, rapid, and requires no washing steps, making it ideal for point-of-care settings. Unlike fluorescent methods, it avoids issues like autofluorescence and photobleaching, broadening its applicability to diverse biofluids. Furthermore, the sensor array contains 80 individually addressable sensors, allowing for the simultaneous measurement of multiple hydrolases in a single reaction. The versatility of this method is demonstrated with substrates for nucleases, Bcu I and DNase I, and the peptidase, human neutrophil elastase. To demonstrate a clinical application, we show that neutrophil elastase in sputum from cystic fibrosis patients hydrolyze the peptide-GMR substrate, and the cleavage rate strongly correlates with a traditional fluorogenic substrate. This innovative assay addresses challenges associated with traditional enzyme measurement techniques, providing a promising tool for real-time quantification of hydrolase activities in diverse biological contexts.

Possible pharmacological targets and mechanisms of sivelestat in protecting acute lung injury

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a life-threatening syndrome induced by various diseases, including COVID-19. In the progression of ALI/ARDS, activated neutrophils play a central role by releasing various inflammatory mediators, including elastase. Sivelestat is a selective and competitive inhibitor of neutrophil elastase. Although its protective effects on attenuating ALI/ARDS have been confirmed in several models of lung injury, clinical trials have presented inconsistent results on its therapeutic efficacy. Therefore, in this report, we used a network pharmacology approach coupled with animal experimental validation to unravel the concrete therapeutic targets and biological mechanisms of sivelestat in treating ALI/ARDS. In bioinformatic analyses, we found 118 targets of sivelestat against ALI/ARDS, and identified six hub genes essential for sivelestat treatment of ALI/ARDS, namely ERBB2, GRB2, PTK2, PTPN11, ESR1, and CCND1. We also found that sivelestat targeted several genes expressed in human lung microvascular endothelial cells after lipopolysaccharide (LPS) treatment at 4 h (ICAM-1, PTGS2, RND1, BCL2A1, TNF, CA2, and ADORA2A), 8 h (ICAM-1, PTGS2, RND1, BCL2A1, MMP1, BDKRB1 and SLC40A1), and 24 h (ICAM-1). Further animal experiments showed that sivelestat was able to attenuate LPS-induced ALI by inhibiting the overexpression of ICAM-1, VCAM-1, and PTGS2 and increasing the phosphorylation of PTK2. Taken together, the bioinformatic findings and experimentative data indicate that the therapeutic effects of sivelestat against ALI/ARDS mainly focus on the early stage of ALI/ARDS by pharmacological modulation of inflammatory reaction, vascular endothelial injury, and cell apoptosis-related molecules.

Vitamin C: Rationale for Its Use in Sepsis-Induced Acute Respiratory Distress Syndrome (ARDS)

Acute respiratory distress syndrome (ARDS) is a life-threatening event that occurs in patients suffering from bacterial, fungal, or viral sepsis. Research performed over the last five decades showed that ARDS is a consequence of severe unrestrained systemic inflammation, which leads to injury of the lung's microvasculature and alveolar epithelium. ARDS leads to acute hypoxic/hypercapnic respiratory failure and death in a significant number of patients hospitalized in intensive care units worldwide. Basic and clinical research performed during the time since ARDS was first described has been unable to construct a pharmacological agent that will combat the inflammatory fire leading to ARDS. In-depth studies of the molecular pharmacology of vitamin C indicate that it can serve as a potent anti-inflammatory agent capable of attenuating the pathobiological events that lead to acute injury of the lungs and other body organs. This analysis of vitamin C's role in the treatment of ARDS includes a focused systematic review of the literature relevant to the molecular physiology of vitamin C and to the past performance of clinical trials using the agent.

Sivelestat sodium alleviated lipopolysaccharide-induced acute lung injury by improving endoplasmic reticulum stress

Acute lung injury (ALI) is a common inflammatory respiratory disorder characterized by a high incidence and mortality rate. This study aimed to investigate the potential therapeutic effects of the neutrophil elastase inhibitor Sivelestat sodium (SIV) in improving endoplasmic reticulum stress (ERS) while treating lipopolysaccharide (LPS)-induced ALI. An ALI model was established using LPS induction. The effects of SIV on ALI were observed both in vivo and in vitro, along with its impact on ERS. Lung tissue damage was assessed using Hematoxylin-eosin (H&E) staining. Lung edema was measured by the lung wet/dry weight ratio. The expression levels of protein kinase R-like ER kinase (PERK), Phospho-protein kinase R-like ER kinase (p-PERK), activating transcription factor 4 (ATF4), eukaryotic translation initiation factor 2α (EIF2a), phosphorylated α subunit of eukaryotic initiation factor 2α (P-EIF2a), and C/EBP homologous protein (CHOP) were analyzed by Western blotting in vivo and in vitro. The levels of tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in Lung tissue samples supernatants were measured by ELISA. Oxidative stress markers were measured by ELISA. Apoptosis was measured using the TUNEL assay. Apoptosis-associated proteins B-cell lymphoma-2 (Bcl-2)、Bcl2-associated × (Bax)、caspase-3 were evaluated through Western blotting in vivo and in vitro. The expression levels of ERS-related proteins, including p-PERK, ATF4, P-EIF2a, and CHOP, were significantly increased in the LPS-induced ALI model. However, SIV markedly reduced the expression levels of these proteins, suppressing the LPS-induced ERS response. Further investigations revealed that SIV exerted a protective effect on ALI by alleviating lung tissue damage and apoptosis, improving lung function, and reducing inflammation and oxidative stress levels. However, when SIV was co-administered with Tunicamycin (TUN), TUN blocked the beneficial effects of SIV on ERS and reversed the protective effects of SIV on ALI. In conclusion, SIV alleviated lung tissue damage and apoptosis, improving lung function, and reducing inflammation and oxidative stress in LPS-induced ALI by improving ERS.

Treatment with sivelestat sodium of acute respiratory distress syndrome induced by chemical pneumonitis: A report of three cases

Inhalation of acid fumes and aspiration of liquid substances or gastric contents may not initiate dyspnea within several hours after exposure but may result in delayed onset of alveolar edema. The present report presents three cases of inhalation or aspiration of chemical substances that resulted in acute respiratory distress syndrome (ARDS). Due to different underlying reasons, three patients developed ARDS resulting from chemical pneumonitis and pulmonary infection. From patients with dyspnea, dry rales could be heard in both lungs, with <92% percutaneous oxygen saturation at room air. All patients were treated using a high-flow nasal cannula and sivelestat sodium. Oxygenation gradually improved and the patients were discharged without adverse events. These cases suggest that early treatment with sivelestat sodium may improve the clinical outcomes of patients with ARDS.

Effect of Sivelestat in the Treatment of Acute Lung Injury and Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis

Background

The efficacy of neutrophil elastase inhibitor sivelestat in the treatment of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) remains controversial. A systematic review and meta-analysis were performed in accordance with the PRISMA guidelines assess the effect of sivelestat on ALI/ARDS patients, different studies were included.

Methods

Electronic databases, National Knowledge Infrastructure (CNKI), Wan fang data, VIP, PubMed, Embase, Springer, Ovid and the Cochrane Library were searched using the following key words: ("Sivelestat" OR "Elaspol") AND ("ARDS" OR "adult respiratory distress syndrome" OR "acute lung injury"). All databases published from January 2000 to August 2022. The treatment group was treated with sivelestat and the control group was given normal saline. The outcome measurements include the mortality of 28-30 days, mechanical ventilation time, ventilation free days, intensive care unit (ICU) stays, oxygenation index (PaO2/FiO2) on day 3, the incidence of adverse events. The literature search was conducted independently by 2 researchers using standardized methods. We used the Cochrane risk-of-bias tool to assess the quality of the included studies. Mean difference (MD), Standardized mean difference (SMD) and relative risk (RR) were calculated using random effects model or fixed effects model. All statistical analyses were performed using RevMan software 5.4.

Results

A total of 2050 patients were enrolled in 15 studies, including 1069 patients in treatment group and 981 patients in the control group. The results of the meta-analysis showed that: compared with the control group, sivelestat can reduce the mortality of 28-30 days (RR = 0.81, 95% CI = 0.66-0.98, p = 0.03) and the incidence of adverse events (RR = 0.91, 95% CI = 0.85-0.98, p = 0.01), shortened mechanical ventilation time (SMD = - 0.32, 95% CI = - 0.60 to - 0.04, p = 0.02) and ICU stays (SMD = - 0.72, 95% CI = - 0.92 to - 0.52, p < 0.00001), increased the ventilation free days (MD = 3.57, 95% CI = 3.42-3.73, p < 0.00001) and improve oxygenation index (PaO2/FiO2) on day 3 (SMD = 0.88, 95% CI = 0.39-1.36, p = 0.0004).

Conclusions

Sivelestat can not only reduce the mortality of ALI/ARDS patients within 28-30 days and the incidence of adverse events, shorten the mechanical ventilation time and ICU stays, increase ventilation free days, but also improve the oxygenation index of patients on days 3, which has a good effect on the treatment of ALI/ARDS. These findings need to be verified in large-scale trials.

Degradation of EGFR on lung epithelial cells by neutrophil elastase contributes to the aggravation of pneumococcal pneumonia

Streptococcus pneumoniae is the main cause of bacterial pneumonia. S. pneumoniae infection has been shown to cause elastase, an intracellular host defense factor, to leak from neutrophils. However, when neutrophil elastase (NE) leaks into the extracellular environment, it can degrade host cell surface proteins such as epidermal growth factor receptor (EGFR) and potentially disrupt the alveolar epithelial barrier. In this study, we hypothesized that NE degrades the extracellular domain of EGFR in alveolar epithelial cells and inhibits alveolar epithelial repair. Using SDS-PAGE, we showed that NE degraded the recombinant EGFR extracellular domain and its ligand EGF, and that the degradation of these proteins was counteracted by NE inhibitors. Furthermore, we confirmed the degradation by NE of EGFR expressed in alveolar epithelial cells in vitro. We show intracellular uptake of EGF and EGFR signaling were downregulated in alveolar epithelial cells exposed to NE, and found cell proliferation was inhibited in these cells These negative effects of NE on cell proliferation were abolished by NE inhibitors. Finally, we confirmed the degradation of EGFR by NE in vivo. Fragments of the extracellular domain of EGFR were detected in bronchoalveolar lavage fluid from pneumococcal pneumonia mice, and the percentage of cells positive for a cell proliferation marker Ki67 in lung tissue was reduced. In contrast, administration of an NE inhibitor decreased EGFR fragments in bronchoalveolar lavage fluid and increased the percentage of Ki67-positive cells. These findings suggest that degradation of EGFR by NE could inhibit the repair of alveolar epithelium and cause severe pneumonia.

Acute Respiratory Distress Syndrome; A Review of Recent Updates and a Glance into the Future

Acute respiratory distress syndrome (ARDS) is a rapidly progressive form of respiratory failure that accounts for 10% of admissions to the ICU and is associated with approximately 40% mortality in severe cases. Despite significant mortality and healthcare burden, the mainstay of management remains supportive care. The recent pandemic of SARS-CoV-2 has re-ignited a worldwide interest in exploring the pathophysiology of ARDS, looking for innovative ideas to treat this disease. Recently, many trials have been published utilizing different pharmacotherapy targets; however, the long-term benefits of these agents remain unknown. Metabolomics profiling and stem cell transplantation offer strong enthusiasm and may completely change the outlook of ARDS management in the near future.

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.

Neutrophil Extracellular Traps Promote Metastases of Colorectal Cancers through Activation of ERK Signaling by Releasing Neutrophil Elastase

Neutrophil extracellular traps (NETs) play important roles in host immunity, as there is increasing evidence of their contribution to the progression of several types of cancers even though their role in colorectal cancers (CRCs) remains unclear. To investigate the clinical relevance of NETs in CRCs, we examined the expression of citrullinated histone H3 using immunohistochemistry and preoperative serum myeloperoxidase-DNA complexes in CRC patients using an enzyme-linked immunosorbent assay. High expression of intratumoral or systemic NETs was found to correlate with poor relapse-free survival (RFS), for which it is an independent prognostic factor. In vitro investigations of CRC cells (HCT116, HT29) revealed that NETs did not affect their proliferation but did promote the migration of CRC cells mediated by neutrophil elastase (NE) released during NETosis to increase extracellular signal-regulated kinase (ERK) activity. In vivo experiments using nude mice (KSN/slc) revealed that NE inhibition suppressed liver metastases in CRC cells, although it did not affect the growth of subcutaneously implanted tumors. Taken together, these results suggest that NET formation correlates with poor prognoses of patients with CRC and that the inhibition of NE could be a potential therapy for CRC metastases.

Sivelestat improves clinical outcomes and decreases ventilator-associated lung injury in children with acute respiratory distress syndrome: a retrospective cohort study

BACKGROUND

Sivelestat, a neutrophil elastase inhibitor, is a selective and targeted therapy for acute respiratory distress syndrome (ARDS) in adults; and it is also reported to apply to children with ARDS. However, there is little evidence of its efficacy in children.

METHODS

This study recruited 212 patients ranging in age from 28 days to 18 years old, and who met the diagnostic criteria for pediatric ARDS (PARDS) while hospitalized in the Intensive Care Department of the Affiliated Children's Hospital of Xi'an Jiaotong University. A total of 125 patients (case group) received sivelestat treatment, and 87 were assigned to the control group. There were no significant differences in gender (P=0.445) or age (P=0.521). Control group data were collected from the Electronic Case Information System for pediatric patients diagnosed with ARDS between March 2017 to January 2020. Data for the case group were collected from the Electronic Case Information System between February 2020 to February 2022. Demographic data, clinically relevant indicators, respiratory parameters were recorded. The 28-day mortality was the primary endpoint; the Kaplan-Meier and log-rank tests were used to evaluate cumulative survival rate.

RESULTS

For general demographic and clinical characteristics, no significant differences were observed between the two groups. Compared to the control group, the case group displayed significant improvements in PaO₂/FiO₂ at 48 h (141±45 vs. 115±21, P<0.001) and 72 h (169±61 vs. 139±40, P<0.001) post-admission, and plateau pressure was lower than that in the control group at 24 h (24±3 vs. 28±7, P<0.001), 48 h (21±4 vs. 26±7, P<0.001), and 72 h (20±2 vs. 25±6, P<0.001) post-admission. Interleukin-8 levels were lower in the case group at 48 and 72 h post-admission. Overall, 28-day mortality was 25.47% (54/212). Twenty-five children died in the sivelestat group, 29 children died in the control group. Survival analysis revealed that cumulative survival in the case group was higher than that in the control group (P=0.028).

CONCLUSIONS

ARDS is expected to have high morbidity and mortality in critical care medicine, and precise targeted drugs are lacking. Our study showed that sivelestat improved prognosis and reduces mortality in children with ARDS.

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.

Targeting Neutrophils for Promoting the Resolution of Inflammation

Acute inflammation is a localized and self-limited innate host-defense mechanism against invading pathogens and tissue injury. Neutrophils, the most abundant immune cells in humans, play pivotal roles in host defense by eradicating invading pathogens and debris. Ideally, elimination of the offending insult prompts repair and return to homeostasis. However, the neutrophils` powerful weaponry to combat microbes can also cause tissue damage and neutrophil-driven inflammation is a unifying mechanism for many diseases. For timely resolution of inflammation, in addition to stopping neutrophil recruitment, emigrated neutrophils need to be disarmed and removed from the affected site. Accumulating evidence documents the phenotypic and functional versatility of neutrophils far beyond their antimicrobial functions. Hence, understanding the receptors that integrate opposing cues and checkpoints that determine the fate of neutrophils in inflamed tissues provides insight into the mechanisms that distinguish protective and dysregulated, excessive inflammation and govern resolution. This review aims to provide a brief overview and update with key points from recent advances on neutrophil heterogeneity, functional versatility and signaling, and discusses challenges and emerging therapeutic approaches that target neutrophils to enhance the resolution of inflammation.

2021 Acute Respiratory Distress Syndrome Update, With Coronavirus Disease 2019 Focus

Acute respiratory distress syndrome (ARDS) is a heterogeneous lung disease responsible for significant morbidity and mortality among critically ill patients, including those infected with severe acute respiratory syndrome coronavirus 2, the virus responsible for coronavirus disease 2019. Despite recent advances in pathophysiology, diagnostics, and therapeutics, ARDS is dangerously underdiagnosed, and supportive lung protective ventilation and prone positioning remain the mainstay interventions. Rescue therapies, including neuromuscular blockade and venovenous extracorporeal membrane oxygenation, remain a key component of clinical practice, although benefits are unclear. Even though coronavirus disease 2019 ARDS has some distinguishing features from traditional ARDS, including delayed onset, hyperinflammatory response, and pulmonary microthrombi, it clinically is similar to traditional ARDS and should be treated with established supportive therapies.

Tissue neutrophil elastase contributes to extracorporeal shock wave lithotripsy-induced kidney damage and the neutrophil elastase inhibitor, sivelestat, attenuates kidney damage with gratifying immunohistopathological and biochemical findings: an experimental study

Although the efficacy of extracorporeal shock wave lithotripsy (ESWL) has been well established within the literature, debate continues on the safety of the procedure while focusing on cellular injury and its long-term consequences. Here, we describe the role of neutrophil elastase (NE) in ESWL-related rat kidney damage and investigate the protective effects of sivelestat, an inhibitor of NE, during the early and late phases. Four groups including control, ESWL alone, ESWL with sivelestat 50 mg/kg and ESWL with treatment of 100 mg/kg, each consisting of ten rats were created. Biochemical parameters of kidney function and damage and immunohistopathological findings were compared in the early (72 h after ESWL) and late (1 week after ESWL) periods between the groups. During the early period, serum and urine creatinine levels and urine kidney injury molecule-1 (KIM-1) levels and the KIM-1/creatinine ratio increased in rats treated with ESWL compared to the control group. Furthermore, increased tissue inflammation, ductal dilatation and hemorrhage, and glomerular, tubular, and interstitial damage with increased NE staining were also detected in the ESWL treatment group. During the late phase, although urine KIM-1 levels remained stable at high levels, other parameters showed significant improvements. On the other hand, the administration of sivelestat 50 mg/kg decreased serum creatinine and urine KIM-1 and KIM-1/creatinine levels significantly in rats treated with ESWL, during the early and late periods. Significant decreases in tissue inflammation, tubular, and interstitial tissue damage were also observed during the early period. In conclusion, ESWL-related kidney tissue damage occurs primarily during the early period, and NE is involved in this process. On the other hand, the NE inhibitor sivelestat attenuated this ESWL-induced kidney damage.

Acute respiratory distress syndrome due to inhalation of acryloyl chloride

Background

Acryloyl chloride is a highly toxic volatile liquid that can cause pulmonary edema. However, no sufficient treatment reports have been published to date. Here, we report a case of acute respiratory distress syndrome (ARDS) caused by acryloyl chloride inhalation.

Case presentation

The patient was a 36‐year‐old man with accidental exposure to acryloyl chloride. The patient had dyspnea and wet cough, with approximately 88% percutaneous oxygen saturation at room air. He was diagnosed with ARDS and admitted to the intensive care unit. Initially, he was treated with a high‐flow nasal cannula and sivelestat sodium. However, due to the possibility of delayed exacerbation, the patient was switched to methylprednisolone. Oxygenation gradually improved, and the patient was discharged on the day 8 of hospitalization.

Conclusion

We report the case of a patient who developed ARDS with delayed exacerbation after the inhalation of acryloyl chloride, which was treated without endotracheal intubation.

Sequence Preference and Scaffolding Requirement for the Inhibition of Human Neutrophil Elastase by Ecotin Peptide

Human neutrophil elastase (hNE) is an abundant serine protease that is a major constituent of lung elastolytic activity. However, when secreted in excess, if not properly attenuated by selective inhibitor proteins, it can have detrimental effects on host tissues, leading to chronic lung inflammation and non-small cell lung cancer. To improve upon the design of inhibitors against hNE for therapeutic applications, here, we report the crystal structure of hNE in complex with an ecotin-derived peptide inhibitor. We show that the peptide binds in the non-prime substrate binding site. Unexpectedly, compared with full-length ecotin, we find that our short linear peptides and circular amide-backbone-linked peptides of ecotin are incapable of efficient hNE inhibition. Our structural insights point to a preferred amino acid sequence and the potential benefit of a scaffold for optimal binding and function of the peptide inhibitor, both of which are retained in the full-length ecotin protein. These findings will aid in the development of effective peptide-based inhibitors against hNE for targeted therapy. This article is protected by copyright. All rights reserved.

The role of neutrophil extracellular traps in acute lung injury

Acute lung injury (ALI) is a heterogeneous inflammatory condition associated with high morbidity and mortality. Neutrophils play a key role in the development of different forms of ALI, and the release of neutrophil extracellular traps (NETs) is emerging as a common pathogenic mechanism. NETs are essential in controlling pathogens, and their defective release or increased degradation leads to a higher risk of infection. However, NETs also contain several pro-inflammatory and cytotoxic molecules than can exacerbate thromboinflammation and lung tissue injury. To reduce NET-mediated lung damage and inflammation, DNase is frequently used in preclinical models of ALI due to its capability of digesting NET DNA scaffold. Moreover, recent advances in neutrophil biology led to the development of selective NET inhibitors, which also appear to reduce ALI in experimental models. Here we provide an overview of the role of NETs in different forms of ALI discussing existing gaps in our knowledge and novel therapeutic approaches to modulate their impact on lung injury.

Matrix metalloproteinase-13 is fully activated by neutrophil elastase and inactivates its serpin inhibitor, alpha-1 antitrypsin: Implications for osteoarthritis

Matrix metalloproteinase-13 (MMP-13) is a uniquely important collagenase that promotes the irreversible destruction of cartilage collagen in osteoarthritis (OA). Collagenase activation is a key control point for cartilage breakdown to occur, yet our understanding of the proteinases involved in this process is limited. Neutrophil elastase (NE) is a well-described proteoglycan-degrading enzyme which is historically associated with inflammatory arthritis, but more recent evidence suggests a potential role in OA. In this study, we investigated the effect of neutrophil elastase on OA cartilage collagen destruction and collagenase activation. Neutrophil elastase induced significant collagen destruction from human OA cartilage ex vivo, in an MMP-dependent manner. In vitro, neutrophil elastase directly and robustly activated pro-MMP-13, and N-terminal sequencing identified cleavage close to the cysteine switch at 72 MKKPR, ultimately resulting in the fully active form with the neo-N terminus of 85 YNVFP. Mole-per-mole, activation was more potent than by MMP-3, a classical collagenase activator. Elastase was detectable in human OA synovial fluid and OA synovia which displayed histologically graded evidence of synovitis. Bioinformatic analyses demonstrated that, compared with other tissues, control cartilage exhibited remarkably high transcript levels of the major elastase inhibitor, (AAT) alpha-1 antitrypsin (gene name SERPINA1), but these were reduced in OA. AAT was located predominantly in superficial cartilage zones, and staining enhanced in regions of cartilage damage. Finally, active MMP-13 specifically inactivated AAT by removal of the serine proteinase cleavage/inhibition site. Taken together, this study identifies elastase as a novel activator of pro-MMP-13 that has relevance for cartilage collagen destruction in OA patients with synovitis.

Role of Neutrophils on the Ocular Surface

The ocular surface is a gateway that contacts the outside and receives stimulation from the outside. The corneal innate immune system is composed of many types of cells, including epithelial cells, fibroblasts, natural killer cells, macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils, mucin, and lysozyme. Neutrophil infiltration and degranulation occur on the ocular surface. Degranulation, neutrophil extracellular traps formation, called NETosis, and autophagy in neutrophils are involved in the pathogenesis of ocular surface diseases. It is necessary to understand the role of neutrophils on the ocular surface. Furthermore, there is a need for research on therapeutic agents targeting neutrophils and neutrophil extracellular trap formation for ocular surface diseases.

Neutrophils as Drivers of Immune Dysregulation in Autoimmune Diseases with Skin Manifestations

Dysregulation in the phenotype and function of neutrophils may play important roles in the initiation and perpetuation of autoimmune responses, including conditions affecting the skin. Neutrophils can have local and systemic effects on innate and adaptive immune cells as well as on resident cells in the skin, including keratinocytes (KCs). Aberrant formation/clearance of neutrophil extracellular traps (NETs) in systemic autoimmunity and chronic inflammatory diseases have been associated with the externalization of modified autoantigens in peripheral blood and tissues. NETs can impact the function of many cells, including macrophages, lymphocytes, dendritic cells, fibroblasts, and KCs. Emerging evidence has unveiled the pathogenic key roles of neutrophils in systemic lupus erythematosus, idiopathic inflammatory myopathies, psoriasis, hidradenitis suppurativa, and other chronic inflammatory conditions. As such, neutrophil-targeting strategies represent promising therapeutic options for these diseases.

Airway Redox Homeostasis and Inflammation Gone Awry: From Molecular Pathogenesis to Emerging Therapeutics in Respiratory Pathology

As aerobic organisms, we are continuously and throughout our lifetime subjected to an oxidizing atmosphere and, most often, to environmental threats. The lung is the internal organ most highly exposed to this milieu. Therefore, it has evolved to confront both oxidative stress induced by reactive oxygen species (ROS) and a variety of pollutants, pathogens, and allergens that promote inflammation and can harm the airways to different degrees. Indeed, an excess of ROS, generated intrinsically or from external sources, can imprint direct damage to key structural cell components (nucleic acids, sugars, lipids, and proteins) and indirectly perturb ROS-mediated signaling in lung epithelia, impairing its homeostasis. These early events complemented with efficient recognition of pathogen- or damage-associated recognition patterns by the airway resident cells alert the immune system, which mounts an inflammatory response to remove the hazards, including collateral dead cells and cellular debris, in an attempt to return to homeostatic conditions. Thus, any major or chronic dysregulation of the redox balance, the air-liquid interface, or defects in epithelial proteins impairing mucociliary clearance or other defense systems may lead to airway damage. Here, we review our understanding of the key role of oxidative stress and inflammation in respiratory pathology, and extensively report current and future trends in antioxidant and anti-inflammatory treatments focusing on the following major acute and chronic lung diseases: acute lung injury/respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and cystic fibrosis.

Exosomes in Sepsis

Sepsis is a severe state of infection with high mortality. Pathogen-associated molecular patterns and damage-associated molecular patterns (DAMPs) initiate dysregulated systemic inflammation upon binding to pattern recognition receptors. Exosomes are endosome-derived vesicles, which carry proteins, lipids and nucleic acids, and facilitate intercellular communications. Studies have shown altered contents and function of exosomes during sepsis. In sepsis, exosomes carry increased levels of cytokines and DAMPs to induce inflammation. Exosomal DAMPs include, but are not limited to, high mobility group box 1, heat shock proteins, histones, adenosine triphosphate, and extracellular RNA. Exosomes released during sepsis have impact on multiple organs, including the lungs, kidneys, liver, cardiovascular system, and central nervous system. Here, we review the mechanisms of inflammation caused by exosomes, and their contribution to multiple organ dysfunction in sepsis.

Neutrophil elastase inhibitor (sivelestat) may be a promising therapeutic option for management of acute lung injury/acute respiratory distress syndrome or disseminated intravascular coagulation in COVID-19

WHAT IS KNOWN AND OBJECTIVE

This article summarizes the effects of sivelestat on acute lung injury/acute respiratory distress syndrome (ALI/ARDS) or ARDS with coagulopathy, both of which are frequently seen in patients with COVID-19.

COMMENT

COVID-19 patients are more susceptible to thromboembolic events, including disseminated intravascular coagulation (DIC). Various studies have emphasized the role of neutrophil elastase (NE) in the development of DIC in patients with ARDS and sepsis. It has been shown that NE inhibition by sivelestat mitigates ALI through amelioration of injuries in alveolar epithelium and vascular endothelium, as well as reversing the neutrophil-mediated increased vascular permeability.

WHAT IS NEW AND CONCLUSIONS

Sivelestat, a selective NE inhibitor, has not been evaluated for its possible therapeutic effects against SARS-CoV-2 infection. Based on its promising beneficial effects in underlying complications of COVID-19, sivelestat could be considered as a promising modality for better management of COVID-19-induced ALI/ARDS or coagulopathy.

Pharmacological management of adult patients with acute respiratory distress syndrome

INTRODUCTION

There is still no definite drug for acute respiratory distress syndrome (ARDS) that is capable of reducing either short-term or long-term mortality. Therefore, great efforts are being made to identify a pharmacological approach that can be really effective.

AREAS COVERED

This review focuses on current challenges and future directions in the pharmacological management of ARDS, regardless of anti-infective treatments. The authors have excluded small randomized controlled trials (RCTs) with less than 60 patients because those studies do not have statistical power for outcome data, and also anecdotal trials but have considered the last meta-analysis on any drug.

EXPERT OPINION

There has been substantial progress in our knowledge of ARDS over the past two decades and many drugs have been used in its treatment. Nevertheless, effective targeted pharmacological treatments for ARDS are still lacking. The likely reason why a pharmacological approach is beneficial for some patients, but harmful for others is that ARDS is an extremely heterogeneous syndrome. To overcome this issue, a precision approach for ARDS, whereby therapies are specifically targeted to patients most likely to benefit, has been proposed. At present, however, the application of this approach seems to be a difficult task.

Pharmacological management of COVID-19 patients with ARDS (CARDS): A narrative review

Coronavirus disease 2019 (COVID-19) is highly infectious. It has been highlighted that if not expertly and individually managed with consideration of the vasocentric features, a COVID-19 patient with an acute respiratory distress syndrome (CARDS) may eventually develop multiorgan failure. Unfortunately, there is still no definite drug for CARDS that is capable of reducing either short-term or long-term mortality and no specific treatments for COVID-19 exist right now. In this narrative review, based on a selective literature search in EMBASE, MEDLINE, Scopus, The Cochrane Library, Web of Science, and Google Scholar and ClinicalTrials.gov, we have examined the emerging evidence on the possible treatment of CARDS. Although numerous pharmacologic therapies to improve clinical outcomes in CARDS have been studied also in clinical trials, none have shown efficacy and there is great uncertainty about their effectiveness. There is still no recommendation for the therapeutic use of any specific agent to treat CARDS because no drugs are validated to have significant efficacy in clinical treatment of COVID-19 patients in large-scale trials. However, there exist a number of drugs that may be useful at least in some patients. The real challenge now is to link the right patient to the right treatment.

RILI model and the Covid-19 pneumonia: The radiation oncologist point of view

•Recent advances in the pathophysiology of COVID-19 pneumonia provided by autopsies have yielded much more informations as the extensive lung parenchyma damages by the virus, macrophages invasion, some lymphocytes and thrombotic features associated to disseminated life-threatening coagulation disorder. •While the hypothetical benefit from a LDR in the treatment symptoms hypotisized by Kirkby C could raise some doubts and disappointed expectations, the propose of the Radiation Induced Lung Injury’s (RILI) model by the Radiotherapy community could contribute to this issue in order to understand the processes and management of this life-threatening disease. •Symptoms, radiological CT findings of the chest and histological features occurring in Covid-19 pneumonia seem to mimic the RILI model in all phases of its course. This similarity could help medical community to adopt several effective therapeutic strategies in the treatment of this life-threatening disease.

Recent advances in the understanding and management of ARDS

The acute respiratory distress syndrome (ARDS) remains a common and highly morbid condition despite advances in the understanding and management of this complex critical illness. Recent work has illuminated the heterogeneity within ARDS and demonstrated the likely impact of heterogeneity on the identification of effective therapeutic interventions. Despite these challenges, new data have also informed the standard of care for ARDS and have resulted in the re-evaluation of previously established therapies, including ventilation strategies, pharmacologic interventions, and rescue therapies. As the field of ARDS continues to evolve, innovative approaches will be needed to further define phenotypes within ARDS and design targeted clinical trials.

Novel findings in neutrophil biology and their impact on cardiovascular disease

Neutrophils are the most abundant circulating leucocytes in healthy humans. These cells are central players during acute inflammatory responses, although a growing body of evidence supports a crucial role in chronic inflammation and chemokines and cytokines related to it as well. Thus, both humoral and cellular components are involved in the development of plaque formation and atherosclerosis. Accordingly, CANTOS trial using an interleukin-1 beta antibody confirmed that inflammatory cytokines contribute to the occurrence of myocardial infarction and cardiac death independent of changes in lipids. Recent data revealed that neutrophils are a heterogeneous population with different subsets and functional characteristics (i.e. CD177+ cells, OLFM4+ neutrophils, proangiogenic neutrophils, neutrophils undergoing reverse migration, and aged neutrophils). Importantly, neutrophils are able to synthesize de novo proteins. Neutrophil extracellular trap generation and NETosis have been considered as very important weapons in sterile inflammation. Neutrophil-derived microvesicles represent another mechanism by which neutrophils amplify inflammatory processes, being found at high levels both at the site of injury and in the bloodstream. Finally, neutrophil aging can influence their functions also in relation with host age. These recent acquisitions in the field of neutrophil biology might pave the way for new therapeutic targets to prevent or even treat patients experiencing cardiovascular (CV) diseases. Here, we discuss novel findings in neutrophil biology, their impact on CV and cerebrovascular diseases, and the potential implementation of these notions into daily clinical practice.

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.

Treatment of spontaneous esophageal rupture (Boerhaave syndrome) using thoracoscopic surgery and sivelestat sodium hydrate

BACKGROUND

The mortality rate of spontaneous esophageal rupture remains 20% to 40% due to severe respiratory failure. We have performed thoracoscopic surgery for esophageal disease at our department since 1994. Sivelestat sodium hydrate reportedly improves the pulmonary outcome in the patients with acute lung injury (ALI).

METHODS

We retrospectively evaluated the usefulness of thoracoscopic surgery and perioperative administration of sivelestat sodium hydrate for spontaneous esophageal rupture in 12 patients who underwent thoracoscopy at our department between 2002 and 2014.

RESULTS

The patient cohort included 11 males and one female (median age, 61 years). The lower left esophageal wall was perforated in all patients. Surgical procedures consisted of thoracoscopic suture and thoracic drainage in six patients, transhiatal suture and thoracoscopic thoracic drainage in five, and thoracoscopic esophagectomy and thoracic drainage in one. The median time from onset to surgery was 8 hours with a surgical duration of 210 minutes, blood loss 260 mL, postoperative ventilator management 1 day, intensive care unit (ICU) stay 5 days, and interval to restoration of oral ingestion 13 days. Postoperative complications included respiratory failure in four patients, pyothorax in three, and leakage in one. There was no instance of perioperative mortality. Regarding perioperative administration of sivelestat sodium hydrate, the postoperative arterial oxygen partial pressure-to-fractional inspired oxygen ratio (P/F) and C-reactive protein (CRP) levels in the administration group were significantly better than those in the non-administration group on postoperative days 4 (P=0.035) and 5 (P=0.037), respectively. In contrast, there was no significant difference between the groups in median time of ventilator management, ICU stay, oral ingestion following surgery, or hospital stay.

CONCLUSIONS

Thoracoscopic surgery obtained acceptable results in all patients, including two with a significant time elapse from onset to treatment. Furthermore, sivelestat sodium hydrate was suggested to help improve postoperative respiration and inflammatory response.