Advancing precision medicine for acute respiratory distress syndrome

Preparation, quality evaluation and preliminary pharmacokinetic-pharmacodynamic studies of synephrine dry powder inhaler

Acute lung injury (ALI) is a lung disease characterized by pulmonary edema caused by an excessive inflammatory response within the lungs and disruption of the alveolar capillary barrier, with a high morbidity and mortality rate in critically ill patients. Dry powder inhalers (DPI) are an effective way of administering medication to improve efficacy, and inhalation administration not only improves efficacy but also increases the bioavailability of the drug. Synephrine, a natural ingredient derived from the fruit of the citrus plant in the Brassicaceae family, has anti-inflammatory and antioxidant properties. In the present study, we prepared a synephrine dry powder inhaler (SYN-DPI) by anti-solvent precipitation method and evaluated it in vivo and in vitro. The in vitro results show that SYN-DPI has low hygroscopicity and good aerodynamic properties. The in vitro and in vivo efficacy results showed that SYN-DPI not only had low toxicity but also possessed good anti-inflammatory and antioxidant capacity, which could significantly reduce inflammation, oxidative stress, and lung injury. Pharmacokinetic results showed that inhalation administration significantly increased SYN bioavailability. In conclusion, this study provides inhalation administration of synephrine as an inhalable formulation that can be used to improve ALI.

Tailoring ventilation and respiratory management in pediatric critical care: optimizing care with precision medicine

PURPOSE OF REVIEW

Critically ill children admitted to the intensive care unit frequently need respiratory care to support the lung function. Mechanical ventilation is a complex field with multiples parameters to set. The development of precision medicine will allow clinicians to personalize respiratory care and improve patients' outcomes.

RECENT FINDINGS

Lung and diaphragmatic ultrasound, electrical impedance tomography, neurally adjusted ventilatory assist ventilation, as well as the use of monitoring data in machine learning models are increasingly used to tailor care. Each modality offers insights into different aspects of the patient's respiratory system function and enables the adjustment of treatment to better support the patient's physiology. Precision medicine in respiratory care has been associated with decreased ventilation time, increased extubation and ventilation wean success and increased ability to identify phenotypes to guide treatment and predict outcomes. This review will focus on the use of precision medicine in the setting of pediatric acute respiratory distress syndrome, asthma, bronchiolitis, extubation readiness trials and ventilation weaning, ventilation acquired pneumonia and other respiratory tract infections.

SUMMARY

Precision medicine is revolutionizing respiratory care and will decrease complications associated with ventilation. More research is needed to standardize its use and better evaluate its impact on patient outcomes.

Defining and subphenotyping ARDS: insights from an international Delphi expert panel

Although the definition of acute respiratory distress syndrome (ARDS) has undergone numerous revisions aimed at enhancing its diagnostic accuracy and clinical practicality, the usefulness and precision of these definitions remain matters of ongoing discussion. In this Position Paper, we report on a Delphi study to reach a consensus on the conceptual model of ARDS, specifically identifying its defining components within clinical, research, and educational contexts as well as exploring the potential role of subphenotyping. We did a four-round Delphi study, involving experts in ARDS research and management from a diverse range of geoeconomic regions and professional backgrounds. Consensus was achieved for the conceptual model of ARDS; key components to be included for an ARDS definition in the context of research, education, and patient management; and the need for further research in subphenotyping ARDS. Additionally, we highlight knowledge gaps and research priorities that could guide future investigations in this area. Our study builds on previous non-Delphi-based consensus processes (eg, the new global definition of ARDS and recent society-based guidelines) by using a rigorous Delphi method that ensured panellist anonymity and used clear quantitative criteria to mitigate potential peer pressure and group conformity. The findings underscore the need to refine the ARDS definition to better account for the heterogeneity of clinical presentations and underlying pathophysiology, and to improve diagnostic precision, including the use of subphenotyping where appropriate.

[Acute respiratory distress syndrome-quo vadis : Innovative and individualized treatment approaches]

Acute respiratory distress syndrome (ARDS) is a heterogeneous clinical syndrome characterized by variable pathophysiology and different therapeutic approaches. Recent guidelines emphasize the importance of prone positioning and venovenous extracorporeal membrane oxygenation (VV-ECMO) for the most severe cases, while routine recruitment maneuvers and extracorporeal CO2-removal techniques are no longer recommended. To further advance the personalization of ARDS therapy, the identification of ARDS phenotypes using latent class analysis offers promising approaches for individualized treatment. Additionally, adaptive platform trials and artificial intelligence (AI)-driven decision-support systems may optimize future ARDS management. The future of ARDS treatment is becoming increasingly individualized, based on improved patient stratification, innovative study designs, and the targeted use of modern technologies. This article summarizes recent developments in ARDS therapy, particularly regarding personalized treatment strategies, new study designs, and the application of artificial intelligence.

Effect of Neutrophil Elastase Inhibitor (Sivelestat Sodium) on Oxygenation in Patients with Sepsis-Induced Acute Respiratory Distress Syndrome

Objective

Neutrophil elastase (NE) plays an important role in the development of acute respiratory distress syndrome (ARDS). Sivelestat sodium, as a selective NE inhibitor, may improve the outcomes of patients with sepsis-induced ARDS in previous studies, but there is a lack of solid evidence. This trial aimed to evaluate the effect of sivelestat sodium on oxygenation in patients with sepsis-induced ARDS.

Methods

We conducted a multicenter, double-blind, randomized, placebo-controlled trial enrolling patients diagnosed with sepsis-induced ARDS admitted within 48 hours of the advent of symptoms. Patients were randomized in a 1:1 fashion to sivelestat or placebo. Trial drugs were administered as a 24-hour continuous intravenous infusion, for a minimum duration of 5 days and a maximum duration of 14 days. The primary outcome was the proportion of PaO2/FiO2 ratio improvement on Day 5 after randomization, defined by a greater than 50% improvement in PaO2/FiO2 compared with that on ICU admission or PaO2/FiO2 reached over 300 mmHg on Day 5.

Results

The study was stopped midway due to a potential between-group difference in mortality observed during the interim analysis. Overall, a total of 70 patients were randomized, of whom 34 were assigned to receive sivelestat sodium and 36 placebo. On day 5, 19/34 (55.9%) patients in the sivelestat group had PaO2/FiO2 ratio improvement compared with 7/36 (19.4%) patients in the placebo group (risk difference, 0.36; 95% CI, 0.14 to 0.56, p<0.001). The Kaplan-Meier curves showed a significantly improved 28-day survival rate in patients receiving sivelestat than those not (hazard ratio, 0.32; 95% CI, 0.11 to 0.95; p=0.041).

Conclusion

In patients with sepsis-induced ARDS, sivelestat sodium could improve oxygenation within the first five days and may be associated with decreased 28-day mortality.

Triptolide alleviates acute lung injury by reducing mitochondrial dysfunction mediated ferroptosis through the STAT3/p53 pathway

Acute lung injury (ALI) represents a severe clinical condition marked by intense pulmonary inflammation and complex pathogenic mechanisms. Triptolide, a potent anti-inflammatory agent derived from the plant Tripterygium wilfordii Hook. f., remains to be fully elucidated for its therapeutic efficacy in ALI. This study aimed to investigate the potential of triptolide in mitigating ALI by modulating ferroptosis and preserving mitochondrial function. Utilizing an ALI model induced by lipopolysaccharide (LPS) both in mice and BEAS-2B cells, we evaluated the impact of triptolide on lung injury, inflammatory cytokines, oxidative stress, and mitochondrial function. RNA sequencing, network pharmacology, molecular docking, and a thermal stability assay for cellular proteins (CETSA) were utilized to identify triptolide targets and pathways. Triptolide significantly alleviated LPS-induced pulmonary pathological changes, downregulated inflammatory cytokines including IL-6, IL-1β, and TNF-α, and reduced reactive oxygen species (ROS) and malondialdehyde (MDA) levels while increasing glutathione (GSH) and superoxide dismutase (SOD) activity. RNA sequencing revealed that triptolide upregulated SLC7A11 and inhibited ferroptosis. Network pharmacology and molecular docking identified the STAT3/p53 pathway as a key mediator of triptolide's action. CETSA confirmed that triptolide binds to and enhances the thermal stability of STAT3 and p53 proteins. This study is the first to elucidate that triptolide mitigates ALI by targeting the STAT3/p53 pathway, preserving mitochondrial function, and inhibiting ferroptosis. Collectively, these results propose that triptolide may serve as an effective therapeutic option for the treatment of ALI.

MEGA: a computational framework to simulate the acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) is a critical condition that necessitates mechanical ventilation (MV) to ensure sufficient ventilation and oxygenation for patients. Intensivists employ various therapeutic tools such as adjusting positive end-expiratory pressure (PEEP) levels or positioning the patient prone. However, practitioners encounter several challenges when dealing with ARDS: high variability among patients and limited understanding of underlying mechanisms. As a result, decision-making by physicians largely relies on experience. Yet, having the ability to estimate the likelihood of a patient responding to different therapeutic approaches would hold significant clinical value. Moreover, gaining a deeper understanding of the biomechanical and physiological phenomena underlying patient responses could inform the development of new MV strategies for ARDS management. To address these challenges, a coupled physiomechanical computational framework based on patient's computed tomography scan data was conceived and implemented. Simulations were conducted for prone positioning and PEEP-increment scenarios. The model results qualitatively align with both literature data and clinical measurements. However, some results diverge quantitatively from clinical measurements, emphasizing the necessity for thorough model calibration. Nonetheless, this serves as a proof of concept that the developed framework could be valuable in supporting intensivists' decision-making processes.NEW & NOTEWORTHY An original computational framework has been developed to simulate respiratory biomechanics and physiology of patients with ARDS. Using patient's CT scans, this spatially resolved model enables the calculation of global parameters (e.g., tidal volumes), but also the detailed distribution of ventilation within the lung, a capability not achievable with conventional single-compartment models commonly used in clinical practice. Furthermore, the framework allows to simulate recruitment maneuvers, including those regularly performed in ICU, such as prone positioning.

Precision medicine in colorectal cancer: genomics profiling and targeted treatment

Precision medicine has revolutionized the treatment of colorectal cancer by enabling a personalized approach tailored to each patient's unique genetic characteristics. Genomic profiling allows for the identification of specific mutations in genes such as KRAS, BRAF, and PIK3CA, which play a crucial role in cell signaling pathways that regulate cell proliferation, apoptosis, and differentiation. This information enables doctors to select targeted therapies that inhibit specific molecular pathways, maximizing treatment effectiveness and minimizing side effects. Precision medicine also facilitates adaptive monitoring of tumor progression, allowing for adjustments in therapy to maintain treatment effectiveness. While challenges such as high costs, limited access to genomic technology, and the need for more representative genomic data for diverse populations remain, collaboration between researchers, medical practitioners, policymakers, and the pharmaceutical industry is crucial to ensure that precision medicine becomes a standard of care accessible to all. With continued advances and support, precision medicine has the potential to improve treatment outcomes, reduce morbidity and mortality rates, and enhance the quality of life for colorectal cancer patients worldwide.

Gas6 induces AIM to suppress acute lung injury in mice by inhibiting NLRP3 inflammasome activation and inducing autophagy

Introduction

Growth arrest-specific 6 (Gas6) protein signaling plays a critical role in maintaining immune homeostasis and regulating inflammation. However, novel mechanisms for modulating macrophage activity through the Gas6 axis are being identified. Gas6 enhances the production of apoptosis inhibitor of macrophages (AIM), a protein with potent anti-inflammatory properties. This study investigates whether Gas6-induced AIM suppresses acute lung injury (ALI) in mice by modulating key inflammatory pathways, including inflammasome activation, autophagy, reactive oxygen species (ROS) generation, and efferocytosis.

Methods

ALI was induced in wild-type (WT) and AIM-/- mice via intratracheal administration of LPS. To evaluate the effects of the Gas6-AIM axis on lung inflammation, recombinant Gas6 (rGas6) was treated intraperitoneally. Inflammatory responses were evaluated using enzyme-linked immunosorbent assay, a cell-sizing analyzer, and Bicinchoninic acid assays. Lung pathology was assessed using hematoxylin-eosin staining. NLRP3 inflammasome activation and autophagy were evaluated using western blot, quantitative real-time PCR, and immunofluorescence. Reactive oxygen species (ROS) levels in alveolar macrophages were measured via fluorescence microscopy, while efferocytosis was assessed in cytospin-stained BAL cells and cultured alveolar macrophages co-cultured with apoptotic Jurkat cells. Additionally, rGas6-mediated effects on NLRP3 inflammasome activation and autophagy were validated in mouse bone marrow-derived macrophages (BMDMs) using siRNAs targeting AIM, Axl, LXRα, or LXRβ.

Results

Proinflammatory cytokine production, neutrophil infiltration, and protein levels in BALF were significantly reduced by rGas6 administration in WT mice but not in AIM-/- mice. Specifically, rGas6 reduced IL-1β and IL-18 levels, caspase-1 activity, and the production of apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC) in alveolar macrophages. Additionally, rGas6 promoted autophagy and efferocytosis in alveolar macrophages while reducing ROS levels through AIM production. These protective effects were absent in AIM-/- mice. Furthermore, siRNA-mediated silencing of Axl, LXRα, LXRβ, or AIM reversed the inhibitory effects of rGas6 on NLRP3 inflammasome activation in BMDMs, and AIM was essential for rGas6-induced autophagy.

Conclusion

Gas6-induced AIM production protects against LPS-induced ALI by inhibiting NLRP3 inflammasome activation, enhancing autophagy and efferocytosis, and reducing oxidative stress. These findings highlight the Gas6-AIM axis as a potential therapeutic target for mitigating inflammatory lung diseases.

Review of Precision Medicine and Diagnosis of Neonatal Illness

Background/Objectives: Precision medicine is a state-of-the-art medicine tactic that tailors information about people's genes, environment, and lifestyle to aid the prevention, diagnosis, and treatment of various diseases to provide an overview of the currently available knowledge and applicability of precision medicine in the diagnosis of different cases admitted to the NICU, such as encephalopathies, respiratory distress syndrome of prematurity, hemodynamic instability, acute kidney injury, sepsis, and hyperbilirubinemia. Methods: The authors searched databases, such as PubMed and PubMed Central, for the terms neonatal "precision medicine", "personalized medicine", "genomics", and "metabolomics", all related to precision medicine in the diagnosis of neonatal illness. The related studies were collected. Results: The review highlights the diagnostic approach that serves to implement precision medicine in the NICU and provide precision diagnosis, monitoring, and treatment. Conclusions: In this review, we projected several diagnostic approaches that provide precision identification of health problems among sick neonates with complex illnesses in the NICU; some are noninvasive and available in ordinary healthcare settings, while others are invasive or not feasible or still in ongoing research as machine learning algorithms. Future studies are needed for the wide implementation of artificial intelligence tools in the diagnosis of neonatal illnesses.

Inflammation and aging-related disease: A transdisciplinary inflammaging framework

Inflammaging, a state of chronic, progressive low-grade inflammation during aging, is associated with several adverse clinical outcomes, including frailty, disability, and death. Chronic inflammation is a hallmark of aging and is linked to the pathogenesis of many aging-related diseases. Anti-inflammatory therapies are also increasingly being studied as potential anti-aging treatments, and clinical trials have shown benefits in selected aging-related diseases. Despite promising advances, significant gaps remain in defining, measuring, treating, and integrating inflammaging into clinical geroscience research. The Clin-STAR Inflammation Research Interest Group was formed by a group of transdisciplinary clinician-scientists with the goal of advancing inflammaging-related clinical research and improving patient-centered care for older adults. Here, we integrate insights from nine medical subspecialties to illustrate the widespread impact of inflammaging on diseases linked to aging, highlighting the extensive opportunities for targeted interventions. We then propose a transdisciplinary approach to enhance understanding and treatment of inflammaging that aims to improve comprehensive care for our aging patients.

Network pharmacology-based strategy to reveal Acacetin against lipopolysaccharide-induced lung injury

BACKGROUND

Acacetin, a flavonoid isolated from Agastache rugosa, exhibits diverse biological activities, such as anti-tumor, anti-inflammatory and antioxidant activities. Its role in treating Lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains incompletely illuminated.

OBJECTIVE

To explore the potential molecular mechanisms of Acacetin in alleviating ALI.

MATERIALS & METHODS

The network pharmacological approach was employed to screen the target genes and pathways of Acacetin. Lung injury was analyzed by Hematoxylin-Eosin (H&E) staining. Bronchoalveolar lavage fluid, serum and lung tissues were collected to detect the levels of proinflammatory cytokines and oxidative stress markers. Immunofluorescence and RT-qPCR experiments were used to observe the expression of CD45, COX2, Ly6G, and related-target proteins. In vitro, RAW264.7 macrophages were stimulated with LPS and treated with AMPK siRNA or an AMPK inhibitor Coumpound C to verify the role of AMPK/nuclear factor erythroid 2-related factor 2 (Nrf2)/high-mobility group box 1 (HMGB1) signaling in Acacetin-mediated alleviation of ALI.

RESULTS

Network data revealed that Acacetin could regulate HMGB1, AMPK, Nrf2, and IL-6. In vivo, Acacetin reversed pathological damage and the release of inflammatory factors, and alleviated oxidative stress and immune cell infiltration in ALI development. Acacetin remarkably upregulated the expression of AMPK and Nrf2, accompanied by HMGB1 downregulation. In vitro, inhibiting AMPK reversed the effects of Acacetin in LPS-treated RAW264.7, due to inactivation of AMPK/Nrf2/HMGB1 pathway.

CONCLUSION

The combination of network pharmacology and experimental studies revealed the role of Acacetin in improving ALI via the AMPK/Nrf2/HMGB1 signaling axis, which provided new insights into the treatment of ALI with Acacetin as a candidate drug.

Inhibition of macrophage inflammasome assembly and pyroptosis with GC-1 ameliorates acute lung injury

Rationale: Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical syndrome with a mortality rate of up to 40%, and it is characterized by a prominent inflammatory cascade. The inflammasome and pyroptosis play crucial regulatory roles in regulating various inflammatory-related diseases by serving as pivotal signaling platforms for inflammatory responses and mediating the release of substantial quantities of inflammatory factors. Our previous studies confirmed that GC-1, a clinical-stage thyroid hormone analog, effectively mitigated pulmonary fibrosis by restoring mitochondrial function in epithelial cells. However, the potential effects of GC-1 on macrophage inflammasome assembly and pyroptosis in lung injury as well as the underlying mechanisms, remain unclear. Methods: The effects of GC-1 on lung injury, oxidative damage and inflammation were evaluated in two murine models of ALI (LPS- or HCl-induced models) by assessing lung pathology, the concentrations of IL-1β and IL-18 in BAL fluid, inflammasome and the levels of inflammasome- and pyroptosis-related proteins. Additionally, the impact of GC-1 on ROS-mediated inflammasome assembly and pyroptosis was investigated by examining ROS levels, Nrf2 signaling, and inflammasome adaptor protein ASC levels in mouse alveolar macrophages and human THP-1 macrophages treated with LPS and ATP. The Nrf2 inhibitor ML385 and the mitochondrial-ROS inhibitor Mito-TEMPO were used to further elucidate the effect of GC-1 on the Nrf2-p53-ASC pathway. Results: GC-1 significantly alleviated inflammation and lung injury in ALI model mice, as indicated by pulmonary pathology, inflammatory cytokine levels, ROS production and pyroptosis rates. Consistently, GC-1 inhibited ASC recruitment and oligomerization in macrophages, which suppressed the gasdermin D-mediated release of IL-1β and IL-18. These findings indicated a reduction in inflammasome assembly and pyroptosis initiation. Further research revealed that GC-1 may mitigate oxidative stress induced by mitochondrial damage through Nrf2 signaling, thereby inhibiting the expression of ROS-activated p53 and the target gene ASC. This protective effect of GC-1 could be reversed by ML385 and mimicked by Mito-TEMPO. Conclusions: This study presents a novel mechanism for treating ALI in which GC-1 inhibits macrophage ROS-mediated inflammasome assembly and pyroptosis through Nrf2-p53-ASC pathway. These findings highlight the promising potential of the use of GC-1 as an anti-inflammatory and antioxidant drug in the treatment of ALI/ARDS.

By activating endothelium histone H4 mediates oleic acid-induced acute respiratory distress syndrome

OBJECTIVE

This study investigated pathogenic role and mechanism of extracellular histone H4 during oleic acid (OA)-induced acute respiratory distress syndrome (ARDS).

METHODS

ARDS was induced by intravenous injection of OA in mice, and evaluated by blood gas, pathological analysis, lung edema, and survival rate. Heparan sulfate (HS) degradation was evaluated using immunofluorescence and flow cytometry. The released von Willebrand factor (vWF) was measured using ELISA. P-selectin translocation and neutrophil infiltration were measured via immunohistochemical analysis. Changes in VE-cadherin were measured by western blot. Blocking antibodies against TLRs were used to investigate the signaling pathway.

RESULTS

Histone H4 in plasma and BALF increased significantly after OA injection. Histone H4 was closely correlated with the OA dose, which determined the ARDS severity. Pretreatment with histone H4 further aggravated pulmonary edema and death rate, while anti-H4 antibody exerted obvious protective effects. Histone H4 directly activated the endothelia. Endothelial activation was evidently manifested as HS degradation, release of vWF, P-selectin translocation, and VE-Cadherin reduction. The synergistic stimulus of activated endothelia was required for effective neutrophil activation by histone H4. Both TLRs and calcium mediated histone H4-induced endothelial activation.

CONCLUSIONS

Histone H4 is a pro-inflammatory and pro-thrombotic molecule in OA-induced ARDS in mice.

Alveolar glycocalyces during health and critical illness

The alveolus, the functional unit of the lung, is comprised of closely approximated alveolar epithelial and endothelial cells, across which gas exchange occurs. This alveolar septum also includes two substantial, intraluminal extracellular matrices: the alveolar epithelial and endothelial glycocalyces. This perspective investigates the distinct structures and homeostatic functions of these two glycocalyces, as well as their distinct fates and consequences during critical illnesses such as sepsis and the acute respiratory distress syndrome. We seek to identify key knowledge gaps, with the goal to inspire future mechanistic investigations that may substantially impact human health and disease.

Pathophysiological Markers of Acute Respiratory Distress Syndrome Severity Are Correlated With Ventilation-Perfusion Mismatch Measured by Electrical Impedance Tomography

OBJECTIVES

Pulmonary ventilation/perfusion (V/Q) mismatch measured by electrical impedance tomography (EIT) is associated with the outcome of patients with the acute respiratory distress syndrome (ARDS), but the underlying pathophysiological mechanisms have not been fully elucidated. The present study aimed to verify the correlation between relevant pathophysiological markers of ARDS severity and V/Q mismatch.

DESIGN

Prospective observational study.

SETTING

General ICU of a university-affiliated hospital.

PATIENTS

Deeply sedated intubated adult patients with ARDS under controlled mechanical ventilation.

INTERVENTIONS

Measures of V/Q mismatch by EIT, respiratory mechanics, gas exchange, lung imaging, and plasma biomarkers.

MEASUREMENTS AND MAIN RESULTS

Unmatched V/Q units were assessed by EIT as the fraction of ventilated nonperfused plus perfused nonventilated lung units. At the same time, plasma biomarkers with proven prognostic and mechanistic significance for ARDS (carbonic anhydrase 9 [CA9], hypoxia-inducible factor 1 [HIF1], receptor for advanced glycation endproducts [RAGE], angiopoietin 2 [ANG2], gas exchange, respiratory mechanics, and quantitative chest CT scans were measured. Twenty-five intubated ARDS patients were included with median unmatched V/Q units of 37.1% (29.2-49.2%). Unmatched V/Q units were correlated with plasma levels of CA9 (rho = 0.47; p = 0.01), HIF1 (rho = 0.40; p = 0.05), RAGE (rho = 0.46; p = 0.02), and ANG2 (rho = 0.42; p = 0.03). Additionally, unmatched V/Q units correlated with plateau pressure ( r = 0.38; p = 0.05) and with the number of quadrants involved on chest radiograph ( r = 0.73; p < 0.01). Regional unmatched V/Q units were correlated with the corresponding fraction of poorly aerated lung tissue ( r = 0.62; p = 0.01) and of lung tissue weight (rho: 0.51; p = 0.04) measured by CT scan.

CONCLUSIONS

In ARDS patients, unmatched V/Q units are correlated with pathophysiological markers of lung epithelial and endothelial dysfunction, increased lung stress, and lung edema. Unmatched V/Q units could represent a comprehensive marker of ARDS severity, reflecting the complex organ pathophysiology and reinforcing their prognostic significance.

Breath and Beyond: Advances in Nanomedicine for Oral and Intranasal Aerosol Drug Delivery

Designing and standardizing drug formulations are crucial for ensuring the safety and efficacy of medications. Nanomedicine utilizes nano drug delivery systems and advanced nanodevices to address numerous critical medical challenges. Currently, oral and intranasal aerosol drug delivery (OIADD) is the primary method for treating respiratory diseases worldwide. With advancements in disease understanding and the development of aerosolized nano drug delivery systems, the application of OIADD has exceeded its traditional boundaries, demonstrating significant potential in the treatment of non-respiratory conditions as well. This study provides a comprehensive overview of the applications of oral and intranasal aerosol formulations in disease treatment. It examines the key challenges limiting the development of nanomedicines in drug delivery systems, formulation processes, and aerosol devices and explores the latest advancements in these areas. This review aims to offer valuable insights to researchers involved in the development of aerosol delivery platforms.

Oxygenation through oral Ox66 in a two-hit rodent model of respiratory distress

Acute respiratory distress syndrome (ARDS) is a complication of pulmonary disease that produces life-threatening hypoxaemia. Despite ventilation and hyperoxic therapies, undetected hypoxia can manifest in capillary beds leading to multi-organ failure. Ox66™ is an ingestible, solid-state form of oxygen designed to supplement oxygen deficits. Twenty-four anaesthetized rats underwent a two-hit model of respiratory distress (ARDS), where a single dose (5 mg/kg) of lipopolysaccharide (LPS) was given intratracheally, and then the respiratory tidal volume was reduced by 40%. After 60 min, animals were randomized to receive Ox66™, or normal saline (NS; vehicle control) via gavage or supplemental inspired oxygen (40% FiO2). A second gavage was administered at 120 min. Cardiovascular function and blood oximetry/chemistry were measured alongside the peripheral spinotrapezius muscle's interstitial oxygenation (PISFO2). ARDS reduced mean arterial pressure (MAP) and PISFO2 compared to baseline (BL) for all treatment groups. Treatment with Ox66 or NS did not improve MAP, but 40% FiO2 caused a rapid return to BL. PISFO2 improved after treatment with Ox66™ and 40% FiO2 and remained elevated for both groups against NS until study conclusion. Both oxygen treatments also suppressed the inflammatory response to LPS, suggesting that Ox66™ can deliver therapeutically-impactful levels of oxygen in situations of pulmonary dysfunction.

Biomarkers of Acute Respiratory Distress Syndrome: Current State and Future Prospects

Biomarkers are an important tool aiding researchers in the study of acute respiratory distress syndrome (ARDS). Mechanisms involving injury to the alveolar-capillary membrane, endothelium and epithelium resulting in lung inflammation and alterations in coagulation pathways have been validated in human trials and have been used to discover promising phenotypes that share similar characteristics and differential treatment responses. The emergence of powerful point-of-care technologies will enable the prospective study of biomarkers for future enrichment trials with the goal of transforming biomarkers into the clinical realm to inform delivery of personalized medicine at the bedside.

Subphenotypic features of patients with sepsis and ARDS: a multicenter cohort study

Objectives

Patients with sepsis are often comorbid with acute respiratory distress syndrome (ARDS), and the phenotypic characteristics of pulmonary and non-pulmonary infections leading to ARDS are still unclear. This study aimed to compare the phenotypic characteristics of ARDS resulting from pulmonary infections and other non-site infections and provide better guidance for clinical treatment.

Methods

We conducted a multicenter cohort analysis using data from the Tianjin Medical University General Hospital, Medical Information Mart for Intensive Care-IV (MIMIC-IV), and the electronic intensive care unit (eICU) databases. The study population consisted of adult patients diagnosed with sepsis and ARDS. The primary objectives were to compare the characteristics and outcomes of patients with pulmonary infection-induced ARDS and those with non-pulmonary infection-induced ARDS using Wilcoxon analysis, Kaplan-Meier curves, correlation analysis, propensity matching scores, and other statistical methods.

Results

Patients with ARDS by pulmonary infection may be more likely to have a history of chronic obstructive pulmonary disease, and abdominal infection was more likely to induce ARDS in sepsis patients with non-pulmonary infection. Pulmonary infections caused by Klebsiella pneumoniae and Acinetobacter baumannii were more likely to induce ARDS. The oxygenation index and prognosis of ARDS patients induced by pulmonary infection were worse than those caused by other infections, with lower PaO2, PaO2/FiO2, and ROX index and longer hospital stay. More ARDS patients with pulmonary infection were given mechanical ventilation therapy, with higher mortality, APACHE II, SOFA, and SAPS II. The further correlation analysis showed that the prognostic scores of ARDS patients were negatively correlated with PaO2/FiO2 and ROX index. The above results were confirmed to varying degrees by propensity matching scores, external cohort validation, and other methods.

Conclusion

Pulmonary infection induces a worse prognosis of ARDS than other site infections in patients with sepsis and ARDS. These patients require heightened vigilance, early intervention, and possibly more aggressive management strategies.

The Thyroid Hormone Analog GC-1 Mitigates Acute Lung Injury by Inhibiting M1 Macrophage Polarization

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a life-threatening condition with a high mortality rate of ≈40%. Thyroid hormones (THs) play crucial roles in maintaining homeostasis of the cellular microenvironment under stress. The previous studies confirmed that the clinical-stage TH analog GC-1 significantly alleviates pulmonary fibrosis by improving the function of mitochondria in epithelial cells. However, the effects of GC-1 on macrophages in lung injury and the related mechanisms remain unclear. This study evaluated the therapeutic effects of GC-1 in two murine models of lipopolysaccharide (LPS)- or hydrochloric acid (HCl)-induced ALI. Additionally, mouse alveolar macrophages (AMs) and human THP-1-derived macrophages are utilized to investigate the impact of GC-1 on macrophage polarization. GC-1 effectively reduces the inflammatory response and lung injury in ALI mice, as evidenced by neutrophil infiltration, cytokine levels, alveolar fluid clearance, and pulmonary pathology. Notably, GC-1 selectively inhibits M1 macrophage polarization, which may be achieved by impeding NF-κB signaling activation through the DNMT3b-PPARγ-NF-κB pathway in a TH receptor β1 (TRβ1)-dependent manner, consequently suppressing the polarization of macrophages toward the M1 phenotype and overproduction of inflammatory cytokines. Overall, these findings highlight the immunomodulatory property of GC-1 as an anti-inflammatory strategy for ALI/ARDS and inflammation-related diseases.

The m6A eraser FTO suppresses ferroptosis via mediating ACSL4 in LPS-induced macrophage inflammation

Acute lung injury (ALI) is a serious disorder characterized by the release of pro-inflammatory cytokines and cascade activation of macrophages. Ferroptosis, a form of iron-dependent cell death triggered by intracellular phospholipid peroxidation, has been implicated as an internal mechanism underlying ALI. In this study, we investigated the effects of m6A demethylase fat mass and obesity-associated protein (FTO) on the inhibition of macrophage ferroptosis in ALI. Using a mouse model of lipopolysaccharide (LPS)-induced ALI, we observed the induction of ferroptosis and its co-localization with the macrophage marker F4/80, suggesting that ferroptosis might be induced in macrophages. Ferroptosis was promoted during LPS-induced inflammation in macrophages in vitro, and the inflammation was counteracted by the ferroptosis inhibitor ferrostatin-1 (fer-1). Given that FTO showed lower expression levels in the lung tissue of mice with ALI and inflammatory macrophages, we further dissected the regulatory capacity of FTO in ferroptosis. The results demonstrated that FTO alleviated macrophage inflammation by inhibiting ferroptosis. Mechanistically, FTO decreased the stability of ACSL4 mRNA via YTHDF1, subsequently inhibiting ferroptosis and inflammation by interrupting polyunsaturated fatty acid consumption. Moreover, FTO downregulated the synthesis and secretion of prostaglandin E2, thereby reducing ferroptosis and inflammation. In vivo, the FTO inhibitor FB23-2 aggravated lung injury, the inflammatory response, and ferroptosis in mice with ALI; however, fer-1 therapy mitigated these effects. Overall, our findings revealed that FTO may function as an inhibitor of the inflammatory response driven by ferroptosis, emphasizing its potential as a target for ALI treatment.

CIRCULATING HEPARAN SULFATE PROFILES IN PEDIATRIC ACUTE RESPIRATORY DISTRESS SYNDROME

ABSTRACT

Introduction: Sepsis-induced degradation of endothelial glycocalyx heparan sulfate (HS) contributes to the pulmonary microvascular endothelial injury characteristic of acute respiratory distress syndrome (ARDS) pathogenesis. Our objectives were to (1) examine relationships between plasma indices of HS degradation and protein biomarkers of endothelial injury and (2) identify patient subgroups characterized by distinct profiles of HS degradation in children with ARDS. Methods: We analyzed prospectively collected plasma (2018-2020) from a cohort of invasively mechanically ventilated children (aged >1 month to <18 years) with ARDS. Mass spectrometry characterized and quantified patterns of HS disaccharide sulfation. Protein biomarkers reflective of endothelial injury (e.g., angiopoietin-2, vascular cell adhesion molecule-1, soluble thrombomodulin) were measured with a multiplex immunoassay. Pearson correlation coefficients were used to construct a biomarker correlation network. Centrality metrics detected influential biomarkers (i.e., network hubs). K-means clustering identified unique patient subgroups based on HS disaccharide profiles. Results: We evaluated 36 patients with pediatric ARDS. HS disaccharide sulfation patterns, 6S, NS, and NS2S, positively correlated with all biomarkers of endothelial injury (all P < 0.05) and were classified as network hubs. We identified three patient subgroups, with cluster 3 (n = 5) demonstrating elevated levels of 6S and N-sulfated HS disaccharides. In cluster 3, 60% of children were female and nonpulmonary sepsis accounted for 60% of cases. Relative to cluster 1 (n = 12), cluster 3 was associated with higher oxygen saturation index (P = 0.029) and fewer 28-day ventilator-free days (P = 0.016). Conclusions: Circulating highly sulfated HS fragments may represent emerging mechanistic biomarkers of endothelial injury and disease severity in pediatric ARDS.

Glucocorticoid therapy for acute respiratory distress syndrome: Current concepts

Acute respiratory distress syndrome (ARDS), a fatal critical disease, is induced by various insults. ARDS represents a major global public health burden, and the management of ARDS continues to challenge healthcare systems globally, especially during the pandemic of the coronavirus disease 2019 (COVID-19). There remains no confirmed specific pharmacotherapy for ARDS, despite advances in understanding its pathophysiology. Debate continues about the potential role of glucocorticoids (GCs) as a promising ARDS clinical therapy. Questions regarding GC agent, dose, and duration in patients with ARDS need to be answered, because of substantial variations in GC administration regimens across studies. ARDS heterogeneity likely affects the therapeutic actions of exogenous GCs. This review includes progress in determining the GC mechanisms of action and clinical applications in ARDS, especially during the COVID-19 pandemic.

Acacetin protects against acute lung injury by upregulating SIRT1/ NF-κB pathway

Acacetin is one of the natural flavone components found in many plants and possesses diverse pharmacological activities. The anti-inflammatory properties and definite mechanism of acacetin remains incompletely illuminated. Here, we evaluated the efficacy of acacetin on lipopolysaccharide (LPS)-induced acute lung injury in vivo and TNF-α-stimulated cellular injury in vitro. As indicated by survival experiments, acacetin reduced mortality and improved survival time of LPS-induced acute lung injury in mice. 50 mg/kg of acacetin obtained higher survival (about 60 %), and 20 mg/kg of acacetin was about 46.7 %. In addition, 20 mg/kg of acacetin rescued lung histopathologic damage in LPS treated mice, lowered lung-to-body weight and lung wet-to-dry ratios, suppressed myeloperoxidase activity in lung tissue, the contents of protein, the numbers of total cells and neutrophils in bronchoalveolar lavage fluid (BALF), and the contents of inflammatory cytokines such as TNF-α, IL-6, IL-17 and IL-1β in BALF. Acacetin also increased the activity and expression of SIRT1, thereby suppressing acetylation-dependent activation NF-κB. Similarly, in vitro, acacetin increased cell viability, reduced levels of TNF-α, IL-6, IL-17, and IL-1β, increased NAD+ levels as well as NAD/NADH ratio, and then up-regulated the activity and expression of SIRT1, and restrained acetylation-dependent activation NF-κB in TNF-α-stimulated A549 cells, which could be abolished by SIRT1 siRNA. Collectively, the current study showed that acacetin exerts a protective effiect on acute lung injury by improving the activity and expression SIRT1, thereby suppressing the acetylation-dependent activation of NF-κB-p65 and the release of downstream inflammatory cytokines.

Neutrophil extracellular traps trigger alveolar epithelial cell necroptosis through the cGAS-STING pathway during acute lung injury in mice

Extensive loss of alveolar epithelial cells (AECs) undergoing necroptosis is a crucial mechanism of acute lung injury (ALI), but its triggering mechanism needs to be thoroughly investigated. Neutrophil extracellular traps (NETs) play a significant role in ALI. However, the effect of NETs on AECs' death has not been clarified. Our study found that intratracheal instillation of NETs disrupted lung tissue structure, suggesting that NETs could induce ALI in mice. Moreover, we observed that NETs could trigger necroptosis of AECs in vivo and in vitro. The phosphorylation levels of RIPK3 and MLKL were increased in MLE12 cells after NETs treatment (P < 0.05). Mechanistically, NETs taken up by AECs through endocytosis activated the cGAS-STING pathway and triggered AECs necroptosis. The expression of cGAS, STING, TBK1 and IRF3 were increased in MLE12 cells treated with NETs (P < 0.05). Furthermore, the cGAS inhibitor RU.521 inhibited NETs-triggered AECs necroptosis and alleviated the pulmonary damage induced by NETs in mice. In conclusion, our study demonstrates that NETs taken up by AECs via endocytosis can activate the cGAS-STING pathway and trigger AECs necroptosis to promote ALI in mice. Our findings indicate that targeting the NETs/cGAS-STING/necroptosis pathway in AECs is an effective strategy for treating ALI.

Subphenotypes in Acute Respiratory Distress Syndrome: Universal Steps Toward Treatable Traits

Patients with acute respiratory distress syndrome (ARDS) have severe respiratory impairment requiring mechanical ventilation resulting in high mortality. Despite extensive research, no effective pharmacological interventions have been identified in unselected ARDS, which has been attributed to the considerable heterogeneity. The identification of more homogeneous subgroups through phenotyping has provided a novel method to improve our pathophysiological understanding, trial design, and, most importantly, patient care through targeted interventions. The objective of this article is to outline a structured, stepwise approach toward identifying and classifying heterogeneity within ARDS and subsequently derive, validate, and integrate targeted treatment options. We present a 6-step roadmap toward the identification of effective phenotype-targeted treatments: development of distinct and reproducible subphenotypes, derivation of a possible parsimonious bedside classification method, identification of possible interventions, prospective validation of subphenotype classification, testing of subphenotype-targeted intervention prospectively in randomized clinical trial (RCT), and finally implementation of subphenotype classification and intervention in guidelines and clinical practice. Based on this framework, the current literature was reviewed. Respiratory physiology, lung morphology, and systemic inflammatory biology subphenotypes were identified. Currently, lung morphology and systemic inflammatory biology subphenotypes are being tested prospectively in RCTs.

Phenotyping COVID-19 respiratory failure in spontaneously breathing patients with AI on lung CT-scan

BACKGROUND

Automated analysis of lung computed tomography (CT) scans may help characterize subphenotypes of acute respiratory illness. We integrated lung CT features measured via deep learning with clinical and laboratory data in spontaneously breathing subjects to enhance the identification of COVID-19 subphenotypes.

METHODS

This is a multicenter observational cohort study in spontaneously breathing patients with COVID-19 respiratory failure exposed to early lung CT within 7 days of admission. We explored lung CT images using deep learning approaches to quantitative and qualitative analyses; latent class analysis (LCA) by using clinical, laboratory and lung CT variables; regional differences between subphenotypes following 3D spatial trajectories.

RESULTS

Complete datasets were available in 559 patients. LCA identified two subphenotypes (subphenotype 1 and 2). As compared with subphenotype 2 (n = 403), subphenotype 1 patients (n = 156) were older, had higher inflammatory biomarkers, and were more hypoxemic. Lungs in subphenotype 1 had a higher density gravitational gradient with a greater proportion of consolidated lungs as compared with subphenotype 2. In contrast, subphenotype 2 had a higher density submantellar-hilar gradient with a greater proportion of ground glass opacities as compared with subphenotype 1. Subphenotype 1 showed higher prevalence of comorbidities associated with endothelial dysfunction and higher 90-day mortality than subphenotype 2, even after adjustment for clinically meaningful variables.

CONCLUSIONS

Integrating lung-CT data in a LCA allowed us to identify two subphenotypes of COVID-19, with different clinical trajectories. These exploratory findings suggest a role of automated imaging characterization guided by machine learning in subphenotyping patients with respiratory failure.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04395482. Registration date: 19/05/2020.

Potential Impact of Subphenotyping in Pharmacologic Management of Acute Respiratory Distress Syndrome

Background: Acute respiratory distress syndrome (ARDS) is an acute inflammatory process in the lungs associated with high morbidity and mortality. Previous research has studied both nonpharmacologic and pharmacologic interventions aimed at targeting this inflammatory process and improving ventilation. Hypothesis: To date, only nonpharmacologic interventions including lung protective ventilation, prone positioning, and high positive end-expiratory pressure ventilation strategies have resulted in significant improvements in patient outcomes. Given the high mortality associated with ARDS despite these advancements, interest in subphenotyping has grown, aiming to improve diagnosis and develop personalized treatment approaches. Data Collection: Previous trials evaluating pharmacologic therapies in heterogeneous populations have primarily demonstrated no positive effect, but hope to show benefit when targeting specific subphenotypes, thus increasing their efficacy, while simultaneously decreasing adverse effects. Results: Although most studies evaluating pharmacologic therapies for ARDS have not demonstrated a mortality benefit, there is limited data evaluating pharmacologic therapies in ARDS subphenotypes, which have found promising results. Neuromuscular blocking agents, corticosteroids, and simvastatin have resulted in a mortality benefit when used in patients with the hyper-inflammatory ARDS subphenotype. Therapeutic Opinion: The use of subphenotyping could revolutionize the way ARDS therapies are applied and therefore improve outcomes while also limiting the adverse effects associated with their ineffective use. Future studies should evaluate ARDS subphenotypes and their response to pharmacologic intervention to advance this area of precision medicine.

The Lipid Intensive Drug Therapy for Sepsis Phase II Pilot Clinical Trial

OBJECTIVES

Low cholesterol levels in early sepsis patients are associated with mortality. We sought to test if IV lipid emulsion administration to sepsis patients with low cholesterol levels would prevent a decline or increase total cholesterol levels at 48 hours.

DESIGN

Phase II, adaptive, randomized pilot clinical trial powered for 48 patients.

SETTING

Emergency department or ICU of an academic medical center.

PATIENTS

Sepsis patients (first 24 hr) with Sequential Organ Failure Assessment greater than or equal to 4 or shock.

INTERVENTIONS

Patients meeting study criteria, including screening total cholesterol levels less than or equal to 100 mg/dL or high-density lipoprotein cholesterol (HDL-C) + low-density lipoprotein cholesterol (LDL-C) less than or equal to 70 mg/dL, were randomized to receive one of three doses of lipid emulsion administered twice in 48 hours or no drug (controls). The primary endpoint was a change in serum total cholesterol (48 hr - enrollment) between groups.

MEASUREMENTS AND MAIN RESULTS

Forty-nine patients were enrolled and randomized. Two patients randomized to lipid emulsion were withdrawn before drug administration. Data for 24 control patients and 23 lipid emulsion patients were analyzed. The mean change in total cholesterol from enrollment to 48 hours was not different between groups and was 5 mg/dL ( sd 20) for lipid emulsion patients, and 2 mg/dL ( sd 18) for control patients ( p = 0.62). The mean changes in HDL-C and LDL-C were similar between groups. Mean change in triglycerides was elevated in lipid emulsion patients (61 mg/dL, sd 87) compared with controls (20 mg/dL, sd 70, p = 0.086). The 48-hour change in SOFA score was -2 (interquartile range [IQR] -4, -1) for control patients and -2 (IQR -3, 0) for lipid emulsion patients ( p = 0.46).

CONCLUSIONS

Administration of IV lipid emulsion to early sepsis patients with low cholesterol levels did not influence change in cholesterol levels from enrollment to 48 hours.

From ICU Syndromes to ICU Subphenotypes: Consensus Report and Recommendations for Developing Precision Medicine in the ICU

Critical care uses syndromic definitions to describe patient groups for clinical practice and research. There is growing recognition that a "precision medicine" approach is required and that integrated biologic and physiologic data identify reproducible subpopulations that may respond differently to treatment. This article reviews the current state of the field and considers how to successfully transition to a precision medicine approach. To impact clinical care, identification of subpopulations must do more than differentiate prognosis. It must differentiate response to treatment, ideally by defining subgroups with distinct functional or pathobiological mechanisms (endotypes). There are now multiple examples of reproducible subpopulations of sepsis, acute respiratory distress syndrome, and acute kidney or brain injury described using clinical, physiological, and/or biological data. Many of these subpopulations have demonstrated the potential to define differential treatment response, largely in retrospective studies, and that the same treatment-responsive subpopulations may cross multiple clinical syndromes (treatable traits). To bring about a change in clinical practice, a precision medicine approach must be evaluated in prospective clinical studies requiring novel adaptive trial designs. Several such studies are underway, but there are multiple challenges to be tackled. Such subpopulations must be readily identifiable and be applicable to all critically ill populations around the world. Subdividing clinical syndromes into subpopulations will require large patient numbers. Global collaboration of investigators, clinicians, industry, and patients over many years will therefore be required to transition to a precision medicine approach and ultimately realize treatment advances seen in other medical fields.

Extracellular histones promote TWIK2-dependent potassium efflux and associated NLRP3 activation in alveolar macrophages during sepsis-induced lung injury

BACKGROUND AND AIM

Sepsis-induced acute lung injury (ALI) is a complex and life-threatening condition lacking specific and efficient clinical treatments. Extracellular histones, identified as a novel type of damage-associated molecular patterns, have been implicated in the inflammatory process of ALI. However, further elucidation is needed regarding the precise mechanism through which extracellular histones induce inflammation. The aim of this study was to investigate whether extracellular histones can activate NLRP3 inflammasome-mediated inflammation in alveolar macrophages (AMs) by affecting TWIK2-dependent potassium efflux.

METHODS AND RESULTS

We conducted experiments using cecal ligation and puncture (CLP) C57BL/6 mice and extracellular histone-stimulated LPS-primed MH-S cells. The results demonstrated a significant increase in the levels of extracellular histones in the plasma and bronchoalveolar lavage fluid (BALF) of CLP mice. Furthermore, neutralizing extracellular histone mitigated lung injury and inflammation in CLP-induced ALI mice. In vitro studies confirmed that extracellular histones upregulated the expression of NLRP3 inflammasome activation-related proteins in MH-S cells, and this effect was dependent on increased potassium efflux mediated by the TWIK2 channel on the plasma membrane. Moreover, extracellular histones directly triggered a substantial influx of calcium, leading to increased Rab11 activity and facilitating the trafficking and location of TWIK2 to the plasma membrane.

CONCLUSION

These findings underscore the critical role of extracellular histone-induced upregulation of TWIK2 expression on the plasma membrane of alveolar macrophages (AMs). This upregulation leads to potassium efflux and subsequent activation of the NLRP3 inflammasome, ultimately exacerbating lung inflammation and injury during sepsis.

Bidirectional pressure: a mini review of ventilator-lung-kidney interactions

Acute kidney injury and respiratory failure that requires mechanical ventilation are both common complications of critical illnesses. Failure of either of these organ systems also increases the risk of failure to the other. As a result, there is a high incidence of patients with concomitant acute kidney injury and the need for mechanical ventilation, which has a devasting impact on intensive care unit outcomes, including mortality. Despite decades of research into the mechanisms of ventilator-lung-kidney interactions, several gaps in knowledge remain and current treatment strategies are primarily supportive. In this review, we outline our current understanding of the mechanisms of acute kidney injury due to mechanical ventilation including a discussion of; 1) The impact of mechanical ventilation on renal perfusion, 2) activation of neurohormonal pathways by positive pressure ventilation, and 3) the role of inflammatory mediators released during ventilator induced lung injury. We also provide a review of the mechanisms by which acute kidney injury increases the risk of respiratory failure. Next, we outline a summary of the current therapeutic approach to preventing lung and kidney injury in the critically ill, including fluid and vasopressor management, ventilator strategies, and treatment of acute kidney injury. Finally, we conclude with a discussion outlining opportunities for novel investigations that may provide a rationale for new treatment approaches.

Advances in nanomaterial-targeted treatment of acute lung injury after burns

Acute lung injury (ALI) is a common complication in patients with severe burns and has a complex pathogenesis and high morbidity and mortality rates. A variety of drugs have been identified in the clinic for the treatment of ALI, but they have toxic side effects caused by easy degradation in the body and distribution throughout the body. In recent years, as the understanding of the mechanism underlying ALI has improved, scholars have developed a variety of new nanomaterials that can be safely and effectively targeted for the treatment of ALI. Most of these methods involve nanomaterials such as lipids, organic polymers, peptides, extracellular vesicles or cell membranes, inorganic nanoparticles and other nanomaterials, which are targeted to reach lung tissues to perform their functions through active targeting or passive targeting, a process that involves a variety of cells or organelles. In this review, first, the mechanisms and pathophysiological features of ALI occurrence after burn injury are reviewed, potential therapeutic targets for ALI are summarized, existing nanomaterials for the targeted treatment of ALI are classified, and possible problems and challenges of nanomaterials in the targeted treatment of ALI are discussed to provide a reference for the development of nanomaterials for the targeted treatment of ALI.

Incidence, mortality, and predictive factors associated with acute respiratory distress syndrome in multiple trauma patients living in high-altitude areas: a retrospective study in Shigatse

Background

Acute respiratory distress syndrome (ARDS) is a severe complication that can lead to fatalities in multiple trauma patients. Nevertheless, the incidence rate and early prediction of ARDS among multiple trauma patients residing in high-altitude areas remain unknown.

Methods

This study included a total of 168 multiple trauma patients who received treatment at Shigatse People's Hospital Intensive Care Unit (ICU) between January 1, 2019 and December 31, 2021. The clinical characteristics of the patients and the incidence rate of ARDS were assessed. Univariable and multivariable logistic regression models were employed to identify potential risk factors for ARDS, and the predictive effects of these risk factors were analyzed.

Results

In the high-altitude area, the incidence of ARDS among multiple trauma patients was 37.5% (63/168), with a hospital mortality rate of 16.1% (27/168). Injury Severity Score (ISS) and thoracic injuries were identified as significant predictors for ARDS using the logistic regression model, with an area under the curve (AUC) of 0.75 and 0.75, respectively. Furthermore, a novel predictive risk score combining ISS and thoracic injuries demonstrated improved predictive ability, achieving an AUC of 0.82.

Conclusions

This study presents the incidence of ARDS in multiple trauma patients residing in the Tibetan region, and identifies two critical predictive factors along with a risk score for early prediction of ARDS. These findings have the potential to enhance clinicians' ability to accurately assess the risk of ARDS and proactively prevent its onset.

Viral and Host Factors Are Associated With Mortality in Hospitalized Patients With COVID-19

BACKGROUND

Persistent mortality in adults hospitalized due to acute COVID-19 justifies pursuit of disease mechanisms and potential therapies. The aim was to evaluate which virus and host response factors were associated with mortality risk among participants in Therapeutics for Inpatients with COVID-19 (TICO/ACTIV-3) trials.

METHODS

A secondary analysis of 2625 adults hospitalized for acute SARS-CoV-2 infection randomized to 1 of 5 antiviral products or matched placebo in 114 centers on 4 continents. Uniform, site-level collection of participant baseline clinical variables was performed. Research laboratories assayed baseline upper respiratory swabs for SARS-CoV-2 viral RNA and plasma for anti-SARS-CoV-2 antibodies, SARS-CoV-2 nucleocapsid antigen (viral Ag), and interleukin-6 (IL-6). Associations between factors and time to mortality by 90 days were assessed using univariate and multivariable Cox proportional hazards models.

RESULTS

Viral Ag ≥4500 ng/L (vs <200 ng/L; adjusted hazard ratio [aHR], 2.07; 1.29-3.34), viral RNA (<35 000 copies/mL [aHR, 2.42; 1.09-5.34], ≥35 000 copies/mL [aHR, 2.84; 1.29-6.28], vs below detection), respiratory support (<4 L O2 [aHR, 1.84; 1.06-3.22]; ≥4 L O2 [aHR, 4.41; 2.63-7.39], or noninvasive ventilation/high-flow nasal cannula [aHR, 11.30; 6.46-19.75] vs no oxygen), renal impairment (aHR, 1.77; 1.29-2.42), and IL-6 >5.8 ng/L (aHR, 2.54 [1.74-3.70] vs ≤5.8 ng/L) were significantly associated with mortality risk in final adjusted analyses. Viral Ag, viral RNA, and IL-6 were not measured in real-time.

CONCLUSIONS

Baseline virus-specific, clinical, and biological variables are strongly associated with mortality risk within 90 days, revealing potential pathogen and host-response therapeutic targets for acute COVID-19 disease.

Bicyclol mitigates lipopolysaccharide-induced acute lung injury through myeloid differentiation factor 88 inhibition

Acute lung injury (ALI) remains a significant clinical challenge due to the absence of effective treatment alternatives. This study presents a new method that employs a screening platform focusing on MyD88 affinity, anti-inflammatory properties, and toxicity. This platform was used to evaluate a 300-compound library known for its anti-inflammatory potential. Among the screened compounds, Bicyclol emerged as a standout, exhibiting MyD88 binding and a significant reduction in LPS-stimulated pro-inflammatory factors production in mouse primary peritoneal macrophages. By targeting MyD88, Bicyclol disrupts the MyD88/TLR4 complex and MyD88 polymer formation, thereby mitigating the MAPKs and NF-κB signaling pathways. In vivo experiments further confirmed Bicyclol's efficacy, demonstrating alleviated ALI symptoms, decreased inflammatory cytokines level, and reduced inflammatory cells presence in lung tissues. These findings were associated with a decrease in mortality in LPS-challenged mice. Overall, Bicyclol represents a promising treatment option for ALI by specifically targeting MyD88 and limiting inflammatory responses.

Exosomes Derived from hucMSCs Primed with IFN-γ Suppress the NF-κB Signal Pathway in LPS-Induced ALI by Modulating the miR-199b-5p/AFTPH Axis

Exosomes (exos) are primarily responsible for the process of mesenchymal stem cells (MSCs) treatment for acute lung injury (ALI), but the mechanism remains unclear, particularly in altered microenvironment. Therefore, this study aimed to investigate the potential mechanism of exos derived from human umbilical cord mesenchymal stem cells (hucMSCs) primed with interferon-gamma (IFN-γ) on ALI and to propose a promising and cell-free strategy. This study extracted exos from hucMSCs supernatant primed and unprimed with IFN-γ marked with IFN-γ-exos and CON-exos, which were identified and traced. IFN-γ-exos administration to ALI models suppressed the NF-κB signaling pathway compared to CON-exos, which were quantified through western blot and immunohistochemical staining. Reverse transcription-quantitative polymerase chain reaction validated miR-199b-5p expression in the IFN-γ-exos and CON-exos treatment groups. Data analysis, a dual-luciferase reporter assay, and cell transfection were conducted to investigate the target binding between miR-199b-5p and Aftiphilin (AFTPH), with AFTPH expression analyzed via cell immunofluorescence and western blot. Co-immunoprecipitation was conducted for the interaction between AFTPH and NF-κB p65. The result revealed that miR-199b-5p was down-regulated in the IFN-γ-exos treatment group, which had a target binding site with AFTPH, and an interaction with NF-κB p65. Consequently, IFN-γ-exos inhibited the NF-κB signaling pathway in ALI in vitro and in vivo through the miR-199b-5p/AFTPH axis. Our results demonstrated new directions of novel and targeted treatment for ALI.

Evaluation of interleukin-1 and interleukin-6 receptor antagonists in a murine model of acute lung injury

The acute exudative phase of acute respiratory distress syndrome (ARDS), a severe form of respiratory failure, is characterized by alveolar damage, pulmonary oedema, and an exacerbated inflammatory response. There is no effective treatment for this condition, but based on the major contribution of inflammation, anti-inflammatory strategies have been evaluated in animal models and clinical trials, with conflicting results. In COVID-19 ARDS patients, interleukin (IL)-1 and IL-6 receptor antagonists (IL-1Ra and IL-6Ra, kineret and tocilizumab, respectively) have shown some efficacy. Moreover, we have previously developed novel peptides modulating IL-1R and IL-6R activity (rytvela and HSJ633, respectively) while preserving immune vigilance and cytoprotective pathways. We aimed to assess the efficacy of these novel IL-1Ra and IL-6Ra, compared to commercially available drugs (kineret, tocilizumab) during the exudative phase (day 7) of bleomycin-induced acute lung injury (ALI) in mice. Our results first showed that none of the IL-1Ra and IL-6Ra compounds attenuated bleomycin-induced weight loss and venousP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ increase. Histological analyses and lung water content measurements also showed that these drugs did not improve lung injury scores or pulmonary oedema, after the bleomycin challenge. Finally, IL-1Ra and IL-6Ra failed to alleviate the inflammatory status of the mice, as indicated by cytokine levels and alveolar neutrophil infiltration. Altogether, these results indicate a lack of beneficial effects of IL-1R and IL-6R antagonists on key parameters of ALI in the bleomycin mouse model.

Imaging the pulmonary vasculature in acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is characterized by a redistribution of regional lung perfusion that impairs gas exchange. While speculative, experimental evidence suggests that perfusion redistribution may contribute to regional inflammation and modify disease progression. Unfortunately, tools to visualize and quantify lung perfusion in patients with ARDS are lacking. This review explores recent advances in perfusion imaging techniques that aim to understand the pulmonary circulation in ARDS. Dynamic contrast-enhanced computed tomography captures first-pass kinetics of intravenously injected dye during continuous scan acquisitions. Different contrast characteristics and kinetic modeling have improved its topographic measurement of pulmonary perfusion with high spatial and temporal resolution. Dual-energy computed tomography can map the pulmonary blood volume of the whole lung with limited radiation exposure, enabling its application in clinical research. Electrical impedance tomography can obtain serial topographic assessments of perfusion at the bedside in response to treatments such as inhaled nitric oxide and prone position. Ongoing technological improvements and emerging techniques will enhance lung perfusion imaging and aid its incorporation into the care of patients with ARDS.

Bakuchiol regulates TLR4/MyD88/NF-κB and Keap1/Nrf2/HO-1 pathways to protect against LPS-induced acute lung injury in vitro and in vivo

Bakuchiol (Bak) possesses a protective effect in acute lung injury (ALI). Nonetheless, the molecular processes that regulate the protective activity of Bak in ALI remain elusive. Lipopolysaccharide (LPS)-treated rats and RLE-6TN cells were used as the ALI models in vivo and in vitro to investigate the function and mechanism of Bak. Rats were divided into four groups: control, LPS, LPS + Bak (30 mg/kg), and LPS + Bak (60 mg/kg). RLE-6TN cells were assigned into four groups: control, LPS, LPS + Bak (10 µM), and LPS + Bak (20 µM). Myeloperoxidase (MPO) and 4-hydroxy-2-nonenal (4-HNE) levels were detected by immunohistochemistry (IHC). The levels of TNF-α, IL-6, and IL-1β were quantified by ELISA. Apoptosis was analyzed by TdT-mediated dUTP nick-end labeling (TUNEL) staining and flow cytometry. Malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and reactive oxygen species (ROS) were assayed to evaluate oxidative stress. In LPS-induced rats, Bak attenuated pathological injury, lung wet/dry weight ratio, MPO expression, and protein concentration and cell number in bronchial alveolar lavage fluid (BALF). Bak decreased the secretion of TNF-α, IL-6, and IL-1β in BALF. Bak reduced MDA content and 4-HNE expression, and increased SOD and GSH-Px activities in lung tissues. Bak also repressed pulmonary apoptosis by decreasing Bax expression and enhancing Bcl-2 expression. In LPS-treated RLE-6TN cells, Bak downregulated the mRNA levels of TNF-α, IL-6, and IL-1β and inhibited the protein expression of iNOS and COX2. Bak decreased MDA level and ROS production and increased SOD and GSH-Px activities. Bak also suppressed cell apoptosis, reduced Bax expression, and increased Bcl-2 expression. Moreover, Bak decreased the expression of TLR4, MyD88, p-IκBα, and p-p65. Additionally, Bak inhibited Keap1 expression and increased Nrf2 and HO-1 levels. Bak protects against LPS-induced inflammation, oxidative stress, and apoptosis in ALI by regulating TLR4/MyD88/NF-κB and Keap1/Nrf2/HO-1 pathways.

Guben Qingfei decoction attenuates LPS-induced acute lung injury by modulating the TLR4/NF-κB and Keap1/Nrf2 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Acute lung injury (ALI) is a life-threatening and widespread disease, with exceptionally high morbidity and mortality rates. Unfortunately, effective drugs for ALI treatment are currently lacking. Guben Qingfei decoction (GBQF) is a Chinese herbal compound known for its efficacy in treating viral pneumonia, yet the precise underlying mechanisms remain unknown.

AIM OF THE STUDY

This study aimed to validate the mitigating effect of GBQF on ALI and to further investigate its mechanism.

MATERIALS AND METHODS

An ALI mice model was established by infusing LPS into the endotracheal tube. The effects of GBQF on ALI were investigated by measuring lung W/D; MPO; BALF total protein concentration; total number of cells; TNF-α, IL-1β, and IL-6 levels; pathological changes in lung tissue, and oxidation products. Immunohistochemistry and Western Blotting were performed to verify the underlying mechanisms. MH-S and BEAS-2B cells were induced by LPS, and the effects of GBQF were confirmed by RT-PCR and immunofluorescence.

RESULTS

GBQF significantly reduced LPS-induced ALI in mice, improved lung inflammation, reduced the production of oxidative products, increased the activity of antioxidant enzymes, and reduced the degree of lung tissue damage. GBQF prevents MH-S cells from releasing inflammatory factors and reduces oxidative damage to BEAS-2B cells. In vivo studies have delved deeper into the mechanism of action of GBQF, revealing its correlation with the TLR4/NF-κB and Keap1/Nrf2 pathways.

CONCLUSIONS

Our study demonstrates that GBQF is an effective treatment for ALI, providing a new perspective on medication development for ALI treatment.

Pharmacologic Treatments in Acute Respiratory Failure

Acute respiratory failure relies on supportive care using non-invasive and invasive oxygen and ventilatory support. Pharmacologic therapies for the most severe form of respiratory failure, acute respiratory distress syndrome (ARDS), are limited. This review focuses on the most promising therapies for ARDS, targeting different mechanisms that contribute to dysregulated inflammation and resultant hypoxemia. Significant heterogeneity exists within the ARDS population. Treatment requires prompt recognition of ARDS and an understanding of which patients may benefit most from specific pharmacologic interventions. The key to finding effective pharmacotherapies for ARDS may rely on deeper understanding of pathophysiology and bedside identification of ARDS subphenotypes.

Exploring the translational landscape of the long noncoding RNA transcriptome in acute respiratory distress syndrome: it is a long way to the top

Acute respiratory distress syndrome (ARDS) poses a significant and widespread public health challenge. Extensive research conducted in recent decades has considerably improved our understanding of the disease pathophysiology. Nevertheless, ARDS continues to rank among the leading causes of mortality in intensive care units and its management remains a formidable task, primarily due to its remarkable heterogeneity. As a consequence, the syndrome is underdiagnosed, prognostication has important gaps and selection of the appropriate therapeutic approach is laborious. In recent years, the noncoding transcriptome has emerged as a new area of attention for researchers interested in biomarker development. Numerous studies have confirmed the potential of long noncoding RNAs (lncRNAs), transcripts with little or no coding information, as noninvasive tools for diagnosis, prognosis and prediction of the therapeutic response across a broad spectrum of ailments, including respiratory conditions. This article aims to provide a comprehensive overview of lncRNAs with specific emphasis on their role as biomarkers. We review current knowledge on the circulating lncRNAs as potential markers that can be used to enhance decision making in ARDS management. Additionally, we address the primary limitations and outline the steps that will be essential for integration of the use of lncRNAs in clinical laboratories. Our ultimate objective is to provide a framework for the implementation of lncRNAs in the management of ARDS.

S100A9-/- alleviates LPS-induced acute lung injury by regulating M1 macrophage polarization and inhibiting pyroptosis via the TLR4/MyD88/NFκB signaling axis

Acute lung injury (ALI) is characterized by pulmonary diffusion abnormalities that may progress to multiple-organ failure in severe cases. There are limited effective treatments for ALI, which makes the search for new therapeutic avenues critically important. Macrophages play a pivotal role in the pathogenesis of ALI. The degree of macrophage polarization is closely related to the severity and prognosis of ALI, and S100A9 promotes M1 polarization of macrophages. The present study assessed the effects of S100A9-gene deficiency on macrophage polarization and acute lung injury. Our cohort study showed that plasma S100A8/A9 levels had significant diagnostic value for pediatric pneumonia and primarily correlated with monocyte-macrophages and neutrophils. We established a lipopolysaccharide (LPS)-induced mouse model of acute lung injury and demonstrated that knockout of the S100A9 gene mitigated inflammation by suppressing the secretion of pro-inflammatory cytokines, reducing the number of inflammatory cells in the bronchoalveolar lavage fluid, and inhibiting cell apoptosis, which ameliorated acute lung injury in mice. The in vitro and in vivo mechanistic studies demonstrated that S100A9-gene deficiency inhibited macrophage M1 polarization and reduced the levels of pulmonary macrophage chemotactic factors and inflammatory cytokines by suppressing the TLR4/MyD88/NF-κB signaling pathway and reversing the expression of the NLRP3 pyroptosis pathway, which reduced cell death. In conclusion, S100A9-gene deficiency alleviated LPS-induced acute lung injury by inhibiting macrophage M1 polarization and pyroptosis via the TLR4/MyD88/NFκB pathway, which suggests a potential therapeutic strategy for the treatment of ALI.

Ferroptosis mediates airway epithelial E-cadherin dysfunction in LPS-induced acute lung injury

BACKGROUND

Loss of E-cadherin in the airway epithelial cells is a critical contributor to the development of ALI/ARDS. Yet the underlying mechanisms are largely unknown. Increasing evidences have revealed the significance of ferroptosis in the pathophysiological process of ALI/ARDS. The aim of this study was to investigate the role of ferroptosis in dysregulation of airway epithelial E-cadherin in ALI/ARDS.

METHODS

BALB/c mice were subjected to intratracheal instillation of lipopolysaccharide (LPS) to establish an ALI model. Two inhibitors of ferroptosis, liproxstatin-1 (Lip-1, at the dose of 10 mg/kg and 30 mg/kg) and ferrostatin-1 (Fer-1, at the dose of 1 mg/kg and 5 mg/kg), were respectively given to the mice through intraperitoneal injection after LPS challenge. The expression of ferroptotic markers, full-length E-cadherin and soluble E-cadherin (sE-cadherin) were both detected.

RESULTS

LPS exposure dramatically down-regulated pulmonary expression of E-cadherin in mice, with profound loss of membrane E-cadherin in the airway epithelial cells and increased secretion of sE-cadherin in the airway lumen. At the same time, we found that the mitochondrial of airway epithelial cells in LPS-exposed mice exhibited significant morphological alterations that are hallmark features of ferroptosis, with smaller volume and increased membrane density. Other makers of ferroptosis were also detected, including increased cytoplasmic levels of iron and lipid peroxidates (MDA), as well as decreased GPX4 expression. 30 mg/kg of Lip-1 not only showed potent protective effects against the LPS-induced injury, inflammation, edema of the lung in those mice, but also rescued airway epithelial E-cadherin expression and decreased the release of sE-cadherin through inhibiting ferroptosis. While no noticeable changes induced by LPS were observed in mice treated with Lip-1 at 10 mg/kg nor Fer-1 at 1 mg/kg or 5 mg/kg.

CONCLUSIONS

Taken together, these data demonstrated that ferroptosis mediates airway epithelial E-cadherin dysfunction in LPS-induced ALI.

A Razor's Edge: Vascular Responses to Acute Inflammatory Lung Injury/Acute Respiratory Distress Syndrome

Historically considered a metabolically inert cellular layer separating the blood from the underlying tissue, the endothelium is now recognized as a highly dynamic, metabolically active tissue that is critical to organ homeostasis. Under homeostatic conditions, lung endothelial cells (ECs) in healthy subjects are quiescent, promoting vasodilation, platelet disaggregation, and anti-inflammatory mechanisms. In contrast, lung ECs are essential contributors to the pathobiology of acute respiratory distress syndrome (ARDS), as the quiescent endothelium is rapidly and radically altered upon exposure to environmental stressors, infectious pathogens, or endogenous danger signals into an effective and formidable regulator of innate and adaptive immunity. These dramatic perturbations, produced in a tsunami of inflammatory cascade activation, result in paracellular gap formation between lung ECs, sustained lung edema, and multi-organ dysfunction that drives ARDS mortality. The astonishing plasticity of the lung endothelium in negotiating this inflammatory environment and efforts to therapeutically target the aberrant ARDS endothelium are examined in further detail in this review.