Acute respiratory distress syndrome

C5a/C5aR regulates Th1/Th2 imbalance in sepsis-associated lung injury by promoting neutrophil activation to increase PAD4 expression

OBJECTIVE

Multi-organ failure frequently complicates sepsis, with lungs being the primary target. T helper (Th) cell activation and phenotypic imbalance among them contribute significantly to sepsis-associated lung injury. Additionally, the complement system could regulate the polarized phenotype of T lymphocytes. Therefore, this study investigated the effect of C5a/C5a receptor (C5aR)/Peptidylarginine deiminase 4 (PAD4) on the Th1/Th2 ratio in sepsis-induced lung injury.

METHODS

ELISA was used to detect the expression of PAD4, HBP, MPO, IL-1β, IL-10, IL-6, IL-4, syndecan-1, endocan and H3Cit. An LPS-induced septic lung injury mouse model was constructed, with HE and PAS stains evaluating lung damage. BCA kit quantified BALF total protein, Western blot examined C5aR, syndecan-1, endocan, PAD4 levels, while TUNEL and flow cytometry assessed tissue cellular apoptosis. Furthermore, flow cytometry was used to detect the +Th1 and Th2 cells proportion in peripheral blood, and CCK-8 was used to detect BEAS-2B activity.

RESULTS

The results indicated that PAD4 and inflammatory factors were increased in lesion samples compared with controls. In sepsis-induced lung injury mice, addition of GSK484, a PAD4 inhibitor, effectively alleviated sepsis-induced lung edema and inflammatory responses. GSK484 was found to inhibit C5a/C5aR expression and suppress apoptosis and lung injury. Furthermore, GSK484 markedly inhibited Th1 cell phenotypes in vitro. Additionally, GSK484 intervention on Th1 cell phenotype further affected lung epithelial cell injury.

CONCLUSION

In summary, we revealed the mechanism of C5a/C5aR-induced PAD4 upregulation via neutrophil activation in sepsis-associated lung injury, causing a Th1/Th2 imbalance and lung injury, providing a novel approach for sepsis-associated lung injuries treatment.

Apium graveolens L. alleviates acute lung injury in human A-549 cells by reducing NF-κB and NLRP3 inflammasome signaling

BACKGROUND

Apium graveolens L. (celery) is a dietary vegetable with anti-inflammatory properties. It has the potential to treat acute lung injury (ALI) caused by COVID-19 or other diseases.

OBJECTIVE

To investigate the effects of Apium graveolens water extract (AGWE) on ALI in human lung A-549 cells induced by lipopolysaccharide (LPS).

MATERIALS AND METHODS

A-549 cells were treated with AGWE for 24 h and then stimulated with 10 μg/mL LPS for another 24 h. The effects of AGWE on cell viability, the inflammatory response, oxidative stress, and apoptosis and their regulatory factors, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and NLR family pyrin domain containing 3 (NLRP3) inflammasome signaling activation were analyzed.

RESULTS

Treatment with 5-50 μg/mL AGWE reversed the decrease in cell viability caused by LPS (p < 0.05). AGWE can reduce interleukin (IL)-1β, IL-6, IL-18, and TNF-α levels; their EC50 values are 61.4, 65.7, 37.8, and 79.7 μg/mL, respectively. AGWE can reduce reactive oxygen species and thiobarbituric acid reactive substances in A-549 cells induced by LPS. AGWE also reduced the levels of apoptosis (EC50 of 74.8 μg/mL) and its regulators (Bid; Caspase-9, -8, and -3; Bax) and increased the levels of the mitochondrial membrane potential in A-549 cells induced by LPS. AGWE can also decrease the protein levels of NLRP3 and Caspase-1 and the activation of NF-κB signaling in A-549 cells induced by LPS.

CONCLUSIONS

These results show that 10 and 50 μg/mL AGWE can reduce the acute inflammation induced by LPS by reducing NF-κB and NLRP3 inflammasome signaling and mitochondria-dependent apoptosis pathways.

Advancements in omics technologies: Molecular mechanisms of acute lung injury and acute respiratory distress syndrome (Review)

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an inflammatory response arising from lung and systemic injury with diverse causes and associated with high rates of morbidity and mortality. To date, no fully effective pharmacological therapies have been established and the relevant underlying mechanisms warrant elucidation, which may be facilitated by multi‑omics technology. The present review summarizes the application of multi‑omics technology in identifying novel diagnostic markers and therapeutic strategies of ALI/ARDS as well as its pathogenesis.

To explore pharmacodynamic substances and mechanism of Xuanfei Baidu Decoction on LPS-induced ALI / ARDS by pharmacochemistry and metabolomics

ETHNOPHARMACOLOGICAL RELEVANCE

Xuanfei Baidu Decoction (XFBD) is made up of five classic prescriptions, which is composed of 13 traditional Chinese medicines, which have the effects of dispersing lung and resolving dampness, clearing heat and evil, purging lung and detoxification. It is used for epidemic diseases caused by damp toxin obstructing lung. In this paper, the endogenous and exogenous metabolites of ALI/ARDS rats after oral administration of XFBD were studied and the material basis and metabolic pathway of XFBD in relieving ALI/ARDS were explained.

MATERIALS AND METHODS

In this study, UPLC-Q-TOF/MS qualitative analysis method was established, and plasma-urine-feces pharmacochemistry was used to identify metabolites in plasma, urine and feces after oral administration of XFBD in rats. RT-PCR and immunohistochemistry were used to study the expression of CYP protein in XFBD and monomeric compounds. In addition, the functional mechanism of XFBD in ALI/ARDS rats was elucidated by non-targeted metabolomics.

RESULTS

A total of 77 prototype components and 389 metabolites in plasma, urine and feces were identified by exogenous components, mainly including oxidation, reduction, hydrolysis, glucuronidation, sulfation and other reactions. The results of RT-PCR and immunohistochemistry showed that the activity of CYP was inhibited under the pathological state of ALI/ARDS. At the same time, XFBD and its monomeric compounds can change the metabolic process of drugs in vivo by inducing or inhibiting the activity of CYPs. The metabolic process of drugs in vivo is the result of the combined action of different CYPs. In addition, a total of 33 differential metabolites were identified in plasma, 45 in urine and 14 in feces, which were mainly related to the synthesis and degradation of ketone bodies, phenylalanine metabolism, tyrosine metabolism, histidine metabolism, butyric acid metabolism and other metabolic pathways.

CONCLUSIONS

This study conducted a relatively scientific and systematic analysis of XFBD. A UPLC-Q-TOF/MS qualitative analysis method was established to identify 77 prototype components and 389 metabolites in plasma, urine and feces of rats after oral administration of XFBD.An ARDS rat model was established to analyze the pharmacokinetic differences of XFBD in normal and ARDS model rats and its regulation effect on CYPs.Non-targeted metabolomics was used to identify the pattern recognition of ARDS pathological model, the diagnosis of disease and the intervention effect of XFBD on ARDS. Preliminary discussion was conducted to provide a theoretical basis for clinical rational drug use.

Anticoagulation Monitoring Strategies During Extracorporeal Membrane Oxygenation (ECMO) Therapy - Differences Between Simultaneously Obtained Coagulation Tests: A Retrospective Single-Center Cohort Study

INTRODUCTION

During extracorporeal membrane oxygenation (ECMO) systemic anticoagulation with unfractionated heparin (UFH) is standard-of-care. However, there is uncertainty regarding optimal anticoagulation monitoring strategies.

METHODS

We retrospectively investigated venovenous and venoarterial ECMO patients at the medical ICUs at the Medical University of Graz, Austria. We analyzed the correlation and concordance of R-time in thromboelastography (TEG), activated partial thromboplastin time (aPTT), and anti-Xa activity. The proportion within target range, the association of coagulation parameters above or below target range (aPTT 54-72 s; equals 1.5-2× upper limit of normal (ULN), anti-Xa activity 0.2-0.5 U/mL, and R-time in assays without heparinase 675-900 s; equals 1.5-2× ULN) with mortality, bleeding events and thrombotic complications were investigated.

RESULTS

We analyzed 671 clusters of simultaneously performed coagulation tests in 85 ECMO cases that fulfilled inclusion criteria. Median age of patients was 57 years and 32% were female. There were poor correlations between the three coagulation tests and the proportion of discordance was 46%. Within the target range were 21% of R-time, 15% of aPTT, and 44% of anti-Xa activity measurements. Singular and multiple bleeding events occurred in 25 and 32 patients, respectively. The most common bleeding locations were catheter and cannula insertion sites followed by pulmonary hemorrhage. In VA-ECMO, anti-Xa activity was associated (OR 1.03 [1.01-1.06], p = 0.005) and correlated with bleeding events (spearman rho 0.49, p = 0.002; point biserial 0.49, p = 0.001). aPTT level below target range was associated with reduced mortality (OR 0.98 [0.97-0.99], p = 0.024). Thrombotic events occurred in six patients with no association of coagulation tests.

CONCLUSION

There was a high rate of discordance and poor correlation between aPTT, anti-Xa activity and R-time in TEG in ECMO patients. We found high rates of bleeding events and in VA-ECMO an association with elevated anti-Xa activity levels.

Aerosol inhalation of rhIL-10 improves acute lung injury in mice by affecting pulmonary neutrophil phenotypes through neutrophil-platelet aggregates

This study investigates the therapeutic effects of recombinant human IL-10 (rhIL-10) administered via aerosol inhalation in acute lung injury (ALI), with a particular focus on neutrophils. It explores how rhIL-10, in the presence of platelets, modulates neutrophil polarization to ameliorate acute lung injury. Initially, the ALI model established in mice demonstrated that aerosol inhalation of rhIL-10 significantly mitigated the cytokine storm in the lungs, reduced pulmonary edema, and alleviated histopathological damage to lung tissue. Additionally, rhIL-10 administration was found to decrease neutrophil infiltration and platelet activation in the lungs of mice, inhibiting the formation of platelet-neutrophil aggregates (PNAs) and promoting the differentiation of neutrophils toward an anti-inflammatory phenotype in the presence of platelets. Subsequently, primary neutrophils and platelets were isolated from mouse bone marrow and blood to explore the underlying mechanisms. The results indicated that rhIL-10 promotes the expression of the signal transducer and activator of transcription 3 (STAT3) and the suppressor of cytokine signaling 3 (SOCS3) in neutrophils while inhibiting the activation of the nuclear factor kappa B (NF-κB) and the NF-κB inhibitor (IκB), which in turn enhances CD40 expression. This interaction facilitates the formation of PNAs and influences neutrophil phenotype differentiation. Furthermore, the application of the STAT3 phosphorylation inhibitor Stattic and CD40 antibody in vivo provided further validation of this potential mechanism. In conclusion, these results indicate that aerosol inhalation of rhIL-10 effectively ameliorates ALI. The underlying mechanism may involve the modulation of the neutrophil STAT/SOCS-IκB/NF-κB-CD40 signaling pathway, promoting interactions between neutrophils and platelets that facilitate the differentiation of neutrophils toward an anti-inflammatory phenotype.

An updated review of pulmonary radiological features of acute and chronic pulmonary COVID-19

PURPOSE OF REVIEW

Significant progress has been made in our understanding of the acute and chronic clinical and radiological manifestations of coronavirus-19 (COVID-19). This article provides an updated review on pulmonary COVID-19, while highlighting the key imaging features that can identify and distinguish acute COVID-19 pneumonia and its chronic sequelae from other diseases.

RECENT FINDINGS

Acute COVID-19 pneumonia typically presents with manifestations of organizing pneumonia on computed tomography (CT). In cases of severe disease, patients clinically progress to acute respiratory distress syndrome, which manifests as diffuse alveolar damage on CT. The most common chronic imaging finding is ground-glass opacities, which commonly resolves, as well as subpleural bands and reticulation. Pulmonary fibrosis is an overall rare complication of COVID-19, with characteristic features, including architectural distortion, and traction bronchiectasis.

SUMMARY

Chest CT can be a helpful adjunct tool in both diagnosing and managing acute COVID-19 pneumonia and its chronic sequelae. It can identify high-risk cases and guide decision-making, particularly in cases of severe or complicated disease. Follow-up imaging can detect persistent lung abnormalities associated with long COVID and guide appropriate management.

Progress in Aptamer Research and Future Applications

Aptamers are short, single-stranded DNA, RNA or synthetic XNA molecules that bind to target molecules with high specificity and affinity. These intrinsically structured RNA or DNA oligonucleotides are not only substitutes for antibodies, but also show great potential for applications in diagnostics, specific drug delivery, and treatment of certain diseases. While the process of aptamer identification and its core functional mechanism known as systematic evolution of exponentially enriched ligands (SELEX), SELEX involves a number of single processes, each contributing to the success or failure of aptamer generation. Today, aptamers are widely used to facilitate basic research discoveries and clinical diagnostics. In addition, aptamers play a promising role as clinical diagnostic and therapeutic agents. This review provides recent advances in this rapidly growing field of research, with special emphasis on aptamer generation and screening, small molecule aptamers, the development of aptamer applications, and applications in clinical medicine. And it also discusses the problems that still exist today with aptamers.

A prediction model for nonresponsive outcomes in critically ill patients with acute respiratory distress syndrome undergoing prone position ventilation: A retrospective cohort study

OBJECTIVE

This study aimed to develop a reliable and effective nomogram model to identify high-risk populations with non-response to prone position ventilation (PPV) in acute respiratory distress syndrome (ARDS) patients.

METHODS

This retrospective cohort study included 175 patients with ARDS undergoing PPV. An improvement of ≥ 20 mmHg in the PaO2/FiO2 after the first PPV was defined as a 'response'. For the construction of the model, all patients were randomly assigned to the train and validation cohort according to 2:1. Multivariate logistic regression was useed to develop the nomogram. The area under the receiver operating characteristic curve (AUC), decision curve and calibration curve were assessed to evaluate the efficiency, clinical utility and calibration of the model.

RESULTS

The overall rate of non-response to PPV in ARDS patients was approximately 32.6 %. In the training cohort and validation cohort, the rate are 29.9 % and 34.5 % respectively. Murray score ≥ 2.5 (OR: 4.29), procalcitonin (PCT) ≥ 2 ng/mL (OR: 2.52), N-terminal pro-B-type natriuretic peptide (Nt-proBNP) ≥ 2000 pg/ml (OR: 2.44), and hemoglobin ≤ 90 g/L (OR: 2.39) were independently associated with the rate of non-response to PPV and combined in prediction model. The model demonstrated good predictive value with AUC of 0.817 and 0.828 in the train and validation cohort. Calibration curve showed good calibration and decision curve analysis indicated favorable clinical utility.

CONCLUSIONS

This study constructed a risk prediction model for non-response to PPV, which demonstrated good predictive value and clinical utility.

IMPLICATIONS FOR CLINICAL PRACTICE

Early identification of prone position response in ARDS is essential for timely alternative treatments, improving patient prognosis and healthcare efficiency. The predictive model included representative indicators of patients with ARDS, encompassing parameters such as the acute lung injury (Murray score), cardiac function (Nt-proBNP), infectious status (PCT), and hemoglobin levels.

Effect of immunostimulatory RNA on the fibrosis development in Bleomycin- or LPS-induced mouse models

Previously, we described a 19-base pair double-stranded RNA with 3'-trinucleotide overhangs, acting as immunostimulatory RNA (isRNA). This molecule demonstrated notable antiproliferative effects on cancer cells, inhibited tumor growth, and elicited immunostimulatory and antiviral responses by inducing cytokine and interferon production. Within this study, we compared the efficiency of lung fibrosis development, initiated in mice by BLM or LPS using different schemes of induction. Then we compared the effect of isRNA used in a preventive or therapeutic regimen on the development of fibrosis in selected BLM- and LPS-induced mouse models and showed that isRNA can be used in pathological conditions accompanied by the development of inflammation and the risk of fibrosis formation, without adverse side effects. Prophylactic regimen of isRNA application is beneficial for prevention of the development of pulmonary fibrosis.

MCU complex: Exploring emerging targets and mechanisms of mitochondrial physiology and pathology

BACKGROUND

Globally, the onset and progression of multiple human diseases are associated with mitochondrial dysfunction and dysregulation of Ca2+ uptake dynamics mediated by the mitochondrial calcium uniporter (MCU) complex, which plays a key role in mitochondrial dysfunction. Despite relevant studies, the underlying pathophysiological mechanisms have not yet been fully elucidated.

AIM OF REVIEW

This article provides an in-depth analysis of the current research status of the MCU complex, focusing on its molecular composition, regulatory mechanisms, and association with diseases. In addition, we conducted an in-depth analysis of the regulatory effects of agonists, inhibitors, and traditional Chinese medicine (TCM) monomers on the MCU complex and their application prospects in disease treatment. From the perspective of medicinal chemistry, we conducted an in-depth analysis of the structure-activity relationship between these small molecules and MCU and deduced potential pharmacophores and binding pockets. Simultaneously, key structural domains of the MCU complex in Homo sapiens were identified. We also studied the functional expression of the MCU complex in Drosophila, Zebrafish, and Caenorhabditis elegans. These analyses provide a basis for exploring potential treatment strategies targeting the MCU complex and provide strong support for the development of future precision medicine and treatments.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The MCU complex exhibits varying behavior across different tissues and plays various roles in metabolic functions. It consists of six MCU subunits, an essential MCU regulator (EMRE), and solute carrier 25A23 (SLC25A23). They regulate processes, such as mitochondrial Ca2+ (mCa2+) uptake, mitochondrial adenosine triphosphate (ATP) production, calcium dynamics, oxidative stress (OS), and cell death. Regulation makes it a potential target for treating diseases, especially cardiovascular diseases, neurodegenerative diseases, inflammatory diseases, metabolic diseases, and tumors.

Platelet membrane-cloaked biomimetic nanoparticles for targeted acute lung injury therapy

Acute lung injury (ALI) is a medical condition characterized by significant morbidity and elevated mortality rates; however, to date, there are no clinically approved pharmacological interventions that are both safe and effective for its treatment. In the pathophysiology of ALI, a robust inflammatory response is a critical factor. Dexamethasone (Dex), a potent glucocorticoid, is commonly employed in clinical settings to manage inflammatory conditions. However, the frequent or high-dose administration of corticosteroids can result in significant adverse effects and long-term complications. In this study, we have developed a biomimetic anti-inflammatory nanosystem, designated PM-LPs@Dex, aimed at treating ALI. This system leverages the inherent affinity of platelets for sites of inflammation, alongside the advantageous drug encapsulation properties of liposomes (LPs). By harnessing the suitable physicochemical characteristics of LPs and the distinctive biological functions of platelet membranes (PM), PM-LPs@Dex is capable of stable and sustained drug release in vitro. Experimental results regarding cellular uptake and biodistribution reveal that PM-LPs@Dex is preferentially internalized by inflammatory cells and exhibits enhanced accumulation in inflamed lung tissue compared to LPs@Dex. Pharmacokinetic studies displayed that PM-LPs@Dex showed prolonged circulation time in blood. Additionally, pharmacodynamic assessments demonstrate that PM-LPs@Dex significantly mitigates the severity of ALI, as evidenced by reductions in pulmonary edema, tissue pathology, bronchoalveolar lavage cell counts, protein concentration, and levels of inflammatory cytokines. Notably, PM-LPs@Dex also exhibits favorable biocompatibility. This research is anticipated to contribute novel strategies for the safe and effective targeted management of inflammatory diseases.

Norwogonin attenuates LPS-induced acute lung injury through inhibiting Src/AKT1/NF-κB signaling pathway

BACKGROUND

Acute lung injury (ALI) has emerged as a critical illness, with sepsis-related ALI accounting for >80 %. In the context of bacterial infection, damage to the pulmonary microvascular barrier leads to inflammatory cell infiltration and plasma component extravasation into pulmonary interstitium. This disruption impairs gas exchange, resulting in hypoxemia. Norwogonin (NWG), a natural plant flavone, has shown potential anti-inflammatory and antioxidative effects. However, whether it could ameliorate sepsis-related ALI and the potential mechanism remains unknown.

PURPOSE

This study aims to investigate the effects and underlying mechanisms of NWG in treating sepsis-related ALI.

METHODS

Male Wistar rats (200-220 g) were used to establish sepsis-related ALI model via intraperitoneal injection of lipopolysaccharide (LPS). Vital signs and arterial blood gas analysis, HE and immunohistochemistry staining, dynamic visualization of the microcirculatory system to observe FITC-dextran leakage and leukocyte adhesion, ELISA assay of inflammatory cytokines, Evans Blue extravasation, measurement of total protein content in bronchoalveolar lavage fluid, determination of the Wet/Dry weight ratio, Western blot and RT-qPCR analysis were used to evaluate NWG's effects and the potential mechanism. Additionally, we employed network pharmacology and molecular docking to identify and evaluate the interaction between NWG and the key targets of ALI. Surface plasmon resonance and enzyme activity assay were utilized to confirm the direct interaction between NWG and the potential targets.

RESULTS

NWG administration improved the vital signs of LPS-stimulated rats. Exposure to LPS led to deteriorated arterial blood gas analysis, prominent lung morphology destruction, neutrophil and M1 macrophage infiltration, leukocyte adhesion, FITC-dextran leakage, elevated secretion of inflammatory cytokines, and aggravated lung edema. NWG intervention effectively mitigated these changes. Furthermore, NWG suppressed NF-κB/NLRP3 signaling and up-regulated endothelial junction proteins. Network pharmacology analysis and molecular docking identified five top key targets: MMP-9, AKT1, COX-2, Src and JAK-2. Western blot and RT-qPCR results confirmed that NWG inhibited the Src/AKT1/NF-κB signaling pathway, and down-regulated the levels of inflammatory factors. Surface plasmon resonance revealed the direct binding between NWG and AKT1, COX-2 and Src, rather than MMP-9. Enzyme activity assay demonstrated that NWG inhibited the activity of AKT1, COX-2 and Src.

CONCLUSION

NWG alleviated inflammation, restored pulmonary microvascular barrier function and improved LPS-induced ALI. These effects were mediated by inhibiting the Src/AKT1/NF-κB signaling pathway through direct targeting of Src, AKT1 and COX-2. Our study provided novel scientific evidence supporting the use of NWG in the treatment of ALI caused by sepsis.

XueBiJing injection improves the symptoms of sepsis-induced acute lung injury by mitigating oxidative stress and ferroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

XBJ injection is approved by the China Food and Drug Administration for the adjunctive treatment of sepsis, and it is derived from the traditional Chinese medicine (TCM) prescription XuefuZhuyu Decoction. It consists of five Chinese herbal extracts: Carthamus tinctorius, Paeonia lactiflora, Salvia miltiorrhiza, Conioselinum anthriscoides 'Chuanxiong' and Angelica sinensis.

AIM OF THE STUDY

The purpose of this study was to explore the relationship between ferroptosis and acute septic lung injury, and to evaluate the improvement effect of XBJ injection on acute lung injury in sepsis.

MATERIALS AND METHODS

Acute lung injury was induced in rats by cecum ligation and puncture, and these rats were treated with XBJ injection. Oxidative stress and inflammation levels were assessed in serum and lung tissue, and tissue samples were collected for histological and protein analyses. To illustrate the mechanism of the improvement effect of XBJ on acute lung injury in sepsis, serum lipidomics was carried out to investigate whether XBJ prevents oxidative stress-induced lipid metabolism disorders. Furthermore, protein expression of ferroptosis-related genes was also examined.

RESULTS

XBJ was shown to be effective in alleviating sepsis-induced ALI. XBJ also improves sepsis-induced acute lung injury by reducing lipid peroxidation and inflammation and modulating ferroptosis pathways. Specifically, compared with the sham group, XBJ downregulated the levels of Fe2+, MDA and GSSG, and reversed the decrease in the levels of GSH and GSH/GSSH in lung tissue. Metabolic pathways such as glycerophospholipid metabolism, phospholipid metabolism, and lipid metabolism associated with ferroptosis were obtained by lipidomic analysis of differential lipid metabolite enrichment, suggesting that ferroptosis occurs in septic rats, and that XBJ inhibits ferroptosis and thereby improves sepsis-induced ALI. Furthermore, XBJ optimises iron metabolism and lipid oxide metabolism by regulating the expression of a series of proteins that are closely related to ferroptosis, such as GPX4, ACSL4, x-CT, and FTH1.

CONCLUSIONS

Our findings, initially, indicated that XBJ ameliorates sepsis-induced ALI by reducing oxidative stress and ferroptosis, revealing a previously unrecognised mechanism by which XBJ ameliorates sepsis-induced ALI.

A comprehensive review of current insights into the virulence factors of SARS-CoV-2

The evolution of SARS-CoV-2 pathogenicity has been a major focus of attention. However, the determinants of pathogenicity are still unclear. Various hypotheses have attempted to elucidate the mechanisms underlying the evolution of viral pathogenicity, but a definitive conclusion has yet to be reached. Here, we review the potential impact of all proteins in SARS-CoV-2 on the viral pathogenic process and analyze the effects of their mutations on pathogenicity evolution. We aim to summarize which virus-encoded proteins are crucial in influencing viral pathogenicity, defined as disease severity following infection. Mutations in these key proteins, which are the virulence factors in SARS-CoV-2, may be the driving forces behind the evolution of viral pathogenicity. Mutations in the S protein can impact viral entry and fusogenicity. Mutations in proteins such as NSP2, NSP5, NSP14, and ORF7a can alter the virus's ability to suppress host protein synthesis and innate immunity. Mutations in NSP3, NSP4, NSP6, N protein, NSP5, and NSP12 may alter viral replication efficiency. The combined effects of mutations in the S protein and NSP6 can significantly reduce viral replication. In addition, various viral proteins, including ORF3a, ORF8, NSP4, Spike protein, N protein, and E protein, directly participate in the inflammatory process. Mutations in these proteins can modulate the levels of inflammation following infection. Collectively, these viral protein mutations can influence SARS-CoV-2 pathogenicity by impacting viral immune evasion, replication capacity, and the level of inflammation mediated by infection. In conclusion, the evolution of SARS-CoV-2 pathogenicity is likely determined by multiple virulence factors.

Knowledge, attitudes and practices of intensive care unit physicians towards the management of acute respiratory distress syndrome in China: a cross-sectional survey

OBJECTIVES

This study aimed to assess the knowledge, attitudes and practices (KAP) of intensive care unit (ICU) physicians in China towards acute respiratory distress syndrome (ARDS).

DESIGN

A cross-sectional study was conducted between September and November 2022.

PARTICIPANTS

A total of 497 ICU physicians participated, with 258 (51.91%) being male and the majority aged 30-40 years (56.74%).

INTERVENTIONS

Participants were surveyed to evaluate their KAP regarding ARDS, with mediation analysis employed to elucidate the association between demographic characteristics and KAP scores.

PRIMARY AND SECONDARY OUTCOME MEASURES

The mean scores for KAP were 11.89±2.64 (range: 0-17), 44.73±4.85 (range: 12-60) and 18.26±3.43 (range: 1-48), respectively. Pearson correlation analysis showed positive correlations between knowledge and attitude (0.367), knowledge and practice (0.582) and attitude and practice (0.314) (all p<0.001).

RESULTS

Mediation analysis indicated that attitude (β=0.07, p<0.001) and hospital type (β=-0.84, p=0.005) had direct effects on practice, while knowledge had significant direct (β=0.68, p<0.001) and indirect (β=0.03, p=0.019) effects. Additionally, education (β=0.47, p<0.001), work experience (β=0.25, p<0.001), hospital classification (β=-0.91, p<0.001), ICU type (β=-0.61, p=0.001) and ARDS experience (β=-1.57, p<0.001) showed various indirect effects on practice.

CONCLUSIONS

ICU physicians in China exhibited inadequate knowledge, moderate attitudes and suboptimal practices regarding ARDS management. Enhancing education and work experience is crucial, along with practical, scenario-based training, to improve KAP in ARDS management.

Design, Synthesis, and Evaluation of Selective PDE4 Inhibitors for the Therapy of Pulmonary Injury

Pulmonary inflammation is the main cause of lung injury. Phosphodiesterase 4 (PDE4) is a promising anti-inflammatory target for the treatment of respiratory diseases. Herein, we designed and synthesized 43 compounds in two novel series of benzimidazole derivatives as PDE4 inhibitors. Among them, compound A5 showed highly selective inhibition of PDE4, good safety, and liver microsomal stability in vitro. A5 administration remarkably attenuated inflammatory infiltration and pathologic injury of the lung in models of acute lung injury in mice and chronic obstructive pulmonary disease (COPD) in mice. In addition, A5 enhanced sputum secretion, relieved cough in mice, and inhibited phosphorylation of p38 MAP kinase, an important protein in the regulation of lung injury. Overall, A5, as an effective PDE4 inhibitor without acute toxicity and gastrointestinal reaction, may be a potent candidate for the treatment of pulmonary injury.

The relationship between steroid treatment and mortality in patients with COVID-19 followed up in an intensive care unit

Aim

Optimal treatment of the coronavirus disease (COVID-19) is still unclear. It has been reported that the use of different doses of corticosteroid treatments may reduce mortality. In our study, we aimed to find the effect of corticosteroid treatment dose on mortality of patients followed up in intensive care due to COVID-19.

Methods

Our retrospective, descriptive and single-centre study included 102 patients diagnosed with COVID-19 who were followed up in intensive care unit, 28 of whom received pulse steroids and 74 of whom received high dose steroids. Laboratory values, duration of intensive care unit and mortality rates of the patients were evaluated.

Results

Mortality was found to be statistically significantly lower in the group receiving pulse steroid compared to the group receiving high dose steroid. In multivariate logistic regression analysis, age and pulse steroid were found to be independent predictors of mortality. According to this analysis, each 10-year increase in age increased mortality by 4.8%, whereas pulse steroid decreased mortality by 79.4%.

Conclusion

In our study, we found that mortality was statistically significantly lower in the group of patients receiving pulse steroids than in the group receiving high dose steroids. We found that the number of patients using pulse steroids was statistically significantly lower in the group with mortality. We found that age and pulse steroid independently determined the patients with mortality.

Coagulation Parameters in Elderly Patients with Severe Pneumonia: Correlation with Disease Severity and Prognosis

Objective

This study aimed to investigate the levels of coagulation parameters in elderly patients with severe pneumonia and analyse their correlation with disease severity and prognosis.

Methods

A retrospective study was conducted on 207 elderly patients (aged ≥60 years) with severe pneumonia admitted to our hospital between January 2022 and December 2023. Demographic data, clinical characteristics and coagulation parameters, including prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time and fibrinogen (FIB), were collected. Patients were divided into survivor and non-survivor groups based on 28-day mortality. The differences in coagulation parameters between groups and their correlation with disease severity and prognosis were analysed.

Results

The 28-day mortality rate was 52.2%. Non-survivors had significantly higher PT, APTT and D-dimer levels and lower FIB levels than survivors (p < 0.05). Multivariate logistic regression analysis showed that elevated PT (odds ratio [OR] = 1.218, 95% confidence interval [CI]: 1.076-1.379, p = 0.002) and D-dimer (OR = 1.109, 95% CI: 1.032-1.192, p = 0.005) were independent risk factors for 28-day mortality. The combined model using PT and D-dimer showed the highest predictive value for 28-day mortality (area under the curve = 0.801, 95% CI: 0.739-0.863, p < 0.001), with a sensitivity of 0.759 and specificity of 0.758.

Conclusion

Coagulation dysfunction is common in elderly patients with severe pneumonia. Prothrombin time and D-dimer levels are closely associated with disease severity and can be valuable indicators for predicting prognosis in this population.

Tangeretin alleviates sepsis-induced acute lung injury by inhibiting ferroptosis of macrophage via Nrf2 signaling pathway

BACKGROUND

Sepsis-induced acute lung injury (ALI) is a severe clinical condition accompanied with high mortality. Tangeretin, which is widely found in citrus fruits, has been reported to exert antioxidant and anti-inflammatory properties. However, whether tangeretin protects against sepsis-induced ALI and the potential mechanisms remain unclear.

METHODS

We established an ALI model via intraperitoneally injected with 5 mg/kg lipopolysaccharides (LPS) for 12 h. Tangeretin was applied intraperitoneally 30 min before LPS treatment. Dexamethasone (Dex) was used as a positive control. Hematoxylin and eosin (HE) staining and protein content in bronchoalveolar lavage fluid (BALF) were determined to detect the degree of lung injury. RNA-seq was also applied to explore the effect of tangeretin on ALI. In vitro, RAW264.7 were treated with Nrf2 siRNA, the expression of ferroptosis-associated biomarkers, including glutathione peroxidase 4 (GPX4) and prostaglandin-endoperoxide synthase 2 (PTGS2) were assessed. Glutathione (GSH), malondialdehyde (MDA) levels, reactive oxygen species (ROS) and inflammatory factors were also determined both in vivo and in vitro. Furthermore, mice were treated with an Nrf2 inhibitor (ML385) to verify the mechanism of tangeretin in inhibiting sepsis-induced lung injury and ferroptosis. Data were analyzed using one way analysis of variance or two-tailed unpaired t tests.

RESULTS

Our study demonstrated that tangeretin significantly alleviated lung injury, reversed the LPS-induced reduction in GPX4 and GSH, and mitigates the elevation of PTGS2 and MDA levels. Tangeretin also reduced 4-HNE and iron levels. Besides, the levels of LPS-stimulated inflammatory factors IL-6, IL-1β and TNF-α were also decreased by tangeretin. RNA-seq and bioinformatics analysis demonstrated that tangeretin inhibited inflammatory response. Mechanistically, we identified that tangeretin inhibited the GPX4-dependent lipid peroxidation through activation of Nrf2. The silence of Nrf2 abolished the inhibitory effect of tangeretin on oxidative stress, inflammatory response and ferroptosis in RAW264.7 cells. Additionally, all the protective effects of tangeretin on ALI were abolished in Nrf2 inhibitor-treated mice.

CONCLUSION

We identified that ferroptosis as a critical mechanism contributing to sepsis-induced ALI. Tangeretin, a promising therapeutic candidate, effectively mitigates ALI through inhibiting ferroptosis via upregulating Nrf2 signaling pathway.

SARS-CoV-2 N protein induces alveolar epithelial apoptosis via NLRP3 pathway in ARDS

Acute Respiratory Distress Syndrome (ARDS) is a severe inflammatory condition often resulting from sepsis and viral infections, including (Severe Acute Respiratory Syndrome Coronavirus 2) SARS-CoV-2. This study investigates the molecular mechanisms by which the SARS-CoV-2 nucleocapsid (N) protein influences alveolar macrophage activation, leading to alveolar epithelial cell apoptosis and exacerbating ARDS. Single-cell RNA sequencing data from ARDS patients were analyzed to identify cell subpopulations and their interactions, revealing significant macrophage-epithelial cell communication through the (NOD-like receptor family pyrin domain containing 3) NLRP3 pathway. Differential gene expression in SARS-CoV-2-infected macrophages highlighted key genes, with WGCNA pinpointing core modules. In vitro experiments demonstrated that N protein overexpression in MH-S macrophages activates the NLRP3 pathway, promoting M1 macrophage polarization and inducing apoptosis in co-cultured MLE-12 epithelial cells. Immunoprecipitation, pull-down assays, Enzyme-Linked Immunosorbent Assay (ELISA), RT-qPCR, Western blotting, and flow cytometry confirmed these findings. In vivo, ARDS mouse models induced by CLP surgery or N protein administration showed increased M1 macrophage infiltration, heightened inflammatory responses, and significant epithelial cell damage, as evidenced by H&E staining, immunofluorescence, RNA-ISH, and ELISA. These results suggest that the SARS-CoV-2 N protein activates the NLRP3 signaling pathway, driving M1 macrophage polarization and the release of pro-inflammatory factors, thereby inducing alveolar epithelial cell apoptosis and worsening ARDS. Targeting this pathway may provide new therapeutic avenues for treating ARDS associated with SARS-CoV-2.

Mucosal immune response in biology, disease prevention and treatment

The mucosal immune system, as the most extensive peripheral immune network, serves as the frontline defense against a myriad of microbial and dietary antigens. It is crucial in preventing pathogen invasion and establishing immune tolerance. A comprehensive understanding of mucosal immunity is essential for developing treatments that can effectively target diseases at their entry points, thereby minimizing the overall impact on the body. Despite its importance, our knowledge of mucosal immunity remains incomplete, necessitating further research. The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has underscored the critical role of mucosal immunity in disease prevention and treatment. This systematic review focuses on the dynamic interactions between mucosa-associated lymphoid structures and related diseases. We delve into the basic structures and functions of these lymphoid tissues during disease processes and explore the intricate regulatory networks and mechanisms involved. Additionally, we summarize novel therapies and clinical research advances in the prevention of mucosal immunity-related diseases. The review also addresses the challenges in developing mucosal vaccines, which aim to induce specific immune responses while maintaining tolerance to non-pathogenic microbes. Innovative therapies, such as nanoparticle vaccines and inhalable antibodies, show promise in enhancing mucosal immunity and offer potential for improved disease prevention and treatment.

A Simple Nomogram for Predicting the Development of ARDS in Postoperative Patients with Gastrointestinal Perforation: A Single-Center Retrospective Study

Background

Acute respiratory distress syndrome (ARDS) is a severe form of organ dysfunction and a common postoperative complication. This study aims to develop a predictive model for ARDS in postoperative patients with gastrointestinal perforation to facilitate early detection and effective prevention.

Methods

In this single-center retrospective study, clinical data were collected from postoperative patients with gastrointestinal perforation admitted to the ICU in Hebei Provincial People's Hospital from October 2017 to May 2024. Univariate analysis and multifactorial logistic regression analysis were used to determine the independent risk factors for developing ARDS. Nomograms were developed to show predictive models, and the discrimination, calibration, and clinical usefulness of the models were assessed using the C-index, calibration plots, and decision curve analysis (DCA).

Results

Two hundred patients were ultimately included for analysis. In the development cohort, 38 (27.1%) of 140 patients developed ARDS, and in the internal validation cohort, 13 (21.7%) of 60 patients developed ARDS. The multivariate logistic regression analysis revealed the site of perforation (OR = 0.164, P = 0.006), the duration of surgery (OR = 0.986, P = 0.008), BMI (OR = 1.197, P = 0.015), SOFA (OR = 1.443, P = 0.001), lactate (OR = 1.500, P = 0.017), and albumin (OR = 0.889, P = 0.007) as the independent risk factors for ARDS development. The area under the curve (AUC) was 0.921 (95% CI: 0.869, 0.973) for the development cohort and 0.894 (95% CI: 0.809, 0.978) for the validation cohort. The calibration curve and decision curve analysis (DCA) demonstrate that the nomogram possesses good predictive value and clinical practicability.

Conclusion

Our research introduced a nomogram that integrates six independent risk factors, facilitating the precise prediction of ARDS risk in postoperative patients following gastrointestinal perforation.

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.

LIN28A-dependent lncRNA NEAT1 aggravates sepsis-induced acute respiratory distress syndrome through destabilizing ACE2 mRNA by RNA methylation

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a life-threatening and heterogeneous disorder leading to lung injury. To date, effective therapies for ARDS remain limited. Sepsis is a frequent inducer of ARDS. However, the precise mechanisms underlying sepsis-induced ARDS remain unclear.

METHODS

Here RNA methylation was detected by methylated RNA immunoprecipitation (MeRIP), RNA stability was determined by RNA decay assay while RNA antisense purification (RAP) was used to identify RNA-protein interaction. Besides, co-immunoprecipitation (Co-IP) was utilized to detect protein-protein interaction. Moreover, mice were injected with lipopolysaccharide (LPS) to establish sepsis-induced ARDS model in vivo.

RESULTS

This study revealed that long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) aggravated lung injury through suppressing angiotensin-converting enzyme 2 (ACE2) in sepsis-induced ARDS models in vitro and in vivo. Mechanistically, NEAT1 declined ACE2 mRNA stability through heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1) in lipopolysaccharide (LPS)-treated alveolar type II epithelial cells (AT-II cells). Besides, NEAT1 destabilized ACE2 mRNA depending on RNA methylation by forming methylated NEAT1/hnRNPA2B1/ACE2 mRNA complex in LPS-treated AT-II cells. Moreover, lin-28 homolog A (LIN28A) improved NEAT1 stability whereas insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) augmented NEAT1 destabilization by associating with LIN28A to disrupt the combination of LIN28A and NEAT1 in LPS-treated AT-II cells. Nevertheless, hnRNPA2B1 increased NEAT1 stability by blocking the interaction between LIN28A and IGF2BP3 in LPS-treated AT-II cells.

CONCLUSIONS

These findings uncover mechanisms of sepsis-triggering ARDS and provide promising therapeutic targets for sepsis-induced ARDS.

Cromolyn sodium reduces LPS-induced pulmonary fibrosis by inhibiting the EMT process enhanced by MC-derived IL-13

BACKGROUND

Sepsis is a systemic inflammatory response caused by infection. When this inflammatory response spreads to the lungs, it can lead to acute lung injury (ALI) or more severe acute respiratory distress syndrome (ARDS). Pulmonary fibrosis is a potential complication of these conditions, and the early occurrence of pulmonary fibrosis is associated with a higher mortality rate. The underlying mechanism of ARDS-related pulmonary fibrosis remains unclear.

METHODS

To evaluate the role of mast cell in sepsis-induced pulmonary fibrosis and elucidate its molecular mechanism. We investigated the level of mast cell and epithelial-mesenchymal transition(EMT) in LPS-induced mouse model and cellular model. We also explored the influence of cromolyn sodium and mast cell knockout on pulmonary fibrosis. Additionally, we explored the effect of MC-derived IL-13 on the EMT and illustrated the relationship between mast cell and pulmonary fibrosis.

RESULTS

Mast cell was up-regulated in the lung tissues of the pulmonary fibrotic mouse model compared to control groups. Cromolyn sodium and mast cell knockout decreased the expression of EMT-related protein and IL-13, alleviated the symptoms of pulmonary fibrosis in vivo and in vitro. The PI3K/AKT/mTOR signaling was activated in fibrotic lung tissue, whereas Cromolyn sodium and mast cell knockout inhibited this pathway.

CONCLUSION

The expression level of mast cell is increased in fibrotic lungs. Cromolyn sodium intervention and mast cell knockout alleviate the symptoms of pulmonary fibrosis probably via the PI3K/AKT/mTOR signaling pathway. Therefore, mast cell inhibition is a potential therapeutic target for sepsis-induced pulmonary fibrosis.

Apoptotic Vesicles Attenuate Acute Lung Injury via CD73-Mediated Inhibition of Platelet Activation and NETosis

Introduction

Acute respiratory distress syndrome (ARDS) is a life-threatening type of acute lung injury (ALI) characterized by elevated mortality rates and long-term effects. To date, no pharmacological treatment has proven effective for ARDS. Mesenchymal stem cell-derived apoptotic vesicles (apoVs) were recently found to have excellent therapeutic potential for inflammatory diseases. In this study, our aim was to investigate the therapeutic effects and underlying mechanisms of apoVs in ALI.

Methods

ALI was induced in mice through intratracheal instillation of lipopolysaccharide (LPS). ApoVs were then administered two hours post-induction, and their impacts on platelet activation, neutrophil infiltration, and NETosis were assessed. Additionally, the role of CD73 in mediating these effects was thoroughly investigated.

Results

ApoVs inhibit platelet activation, thereby impeding the infiltration of neutrophils into the lung and the initiation of NETosis, ultimately alleviating ALI. Remarkably, apoVs were enriched with CD73, which was critical for apoV-mediated repression of platelet activation and neutrophil NETosis, as well as the therapeutic effects observed in lung injury.

Conclusion

This study reveals that apoVs inhibit platelet activity and neutrophil NETosis via CD73, offering an innovative and effective cell-free therapeutic strategy for ALI/ARDS.

Association Between Platelet-Albumin-Bilirubin Grade and the 30-Day Mortality in Patients with Acute Respiratory Distress Syndrome: Evidence from the MIMIC-IV Database

Background

The platelet-albumin-bilirubin (PALBI) grade is a comprehensive assessment index of liver function. Liver dysfunction is a key determinant of the pathogenesis and resolution of acute respiratory distress syndrome (ARDS), which affects the prognosis of patients.

Aims

To evaluate the association of PALBI grade with the risk of 30-day mortality in patients with ARDS.

Study Design

Retrospective cohort study.

Methods

Univariate and multivariate Cox proportional hazards models were used to evaluate the association between PALBI grade and the 30-day mortality in patients with ARDS; results were described as hazard ratios (HRs) and 95% confidence intervals (CIs). This association was further assessed by subgroup analyses stratified based on age, sex, and complications.

Results

A total of 2,841 patients with ARDS were included, of whom, 703 (24.74%) died within 30 days. After adjusting all covariates, a higher PALBI grade was associated with higher odds of 30-day mortality (HR: 1.55, 95% CI: 1.05-2.29). High PALBI grade was related to higher odds of 30-day mortality in patients with ARDS aged ≥ 65 years (HR: 2.30, 95% CI: 1.06-5.01), males (HR: 2.10, 95% CI: 1.29-3.44), without sepsis (HR: 1.71, 95% CI: 1.11-2.64), without pneumonia (HR: 1.86, 95% CI: 1.19-2.91), and without any history of chronic obstructive pulmonary disease (HR: 1.93, 95% CI: 1.28-2.91).

Conclusion

The PALBI grade was positively associated with 30-day mortality in patients with ARDS. The present study provides a reference for risk stratification management of patients with ARDS to improve short-term prognosis.

Establishment of an inflammation-related acute lung injury/acute respiratory distress syndrome rat model supported by venovenous extracorporeal membrane oxygenation

BACKGROUND

The major concerns for patients who have acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) associated with coronavirus disease 2019 or sepsis and undergone successful venovenous extracorporeal membrane oxygenation (VV ECMO) include a low survival rate and an uncontrollable inflammatory response. This study aimed to introduce an inflammation-related ALI/ARDS rat model supported by VV ECMO that is more suitable for clinical application to assess the immune response and thereby further improve survival after VV ECMO.

METHODS

Rats were randomly divided into three groups: the sham group, the lipopolysaccharide (LPS) group, and the LPS + ECMO group. ALI/ARDS was induced via intratracheal instillation of LPS in rats. A 5.5 F specially designed bicaval cannulation was placed in the external jugular vein for drainage and reflux. Femoral artery cannulation was used to monitor blood pressure during surgery. Arterial blood gas was measured at baseline and 3 h after VV ECMO support. Finally, lung tissue, bronchoalveolar lavage fluid (BALF) and blood samples were harvested for further evaluation.

RESULTS

All LPS-induced ALI/ARDS rats were successfully supported by VV ECMO. The rats survived during the supporting process and maintained effective blood pressure and electrocardiogram (ECG) activity. Compared with the LPS group, VV ECMO support provided oxygen supply to restore lung function and reduced lung injury.

CONCLUSION

We successfully established an inflammation-related ALI/ARDS rat model supported by VV ECMO, in which VV ECMO support alleviated lung injury. Our rat model provides a new tool for immunological research on inflammation-related ALI/ARDS during VV ECMO.

Tranexamic Acid and Pulmonary Complications: A Secondary Analysis of an EAST Multicenter Trial

BACKGROUND

Anti-inflammatory effects of tranexamic acid (TXA) in reducing trauma endotheliopathy may protect from acute lung injury. Clinical data showing this benefit in trauma patients is lacking. We hypothesized that TXA administration mitigates pulmonary complications in penetrating trauma patients.

MATERIALS AND METHODS

This is a post-hoc analysis of a multicenter, prospective, observational study of adults (18+ years) with penetrating torso and/or proximal extremity injury presenting at 25 urban trauma centers. Tranexamic acid administration in the prehospital setting or within three hours of admission was examined. Participants were propensity matched to compare similarly injured patients. The primary outcome was development of pulmonary complication (ARDS and/or pneumonia).

RESULTS

A total of 2382 patients were included, and 206 (8.6%) received TXA. Of the 206, 93 (45%) received TXA prehospital and 113 (55%) received it within three hours of hospital admission. Age, sex, and incidence of massive transfusion did not differ. The TXA group was more severely injured, more frequently presented in shock (SBP < 90 mmHg), developed more pulmonary complications, and had lower survival (P < 0.01 for all). After propensity matching, 410 patients remained (205 in each cohort) with no difference in age, sex, or rate of shock. On logistic regression, increased emergency department heart rate was associated with pulmonary complications. Tranexamic acid was not associated with different rate of pulmonary complications or survival on logistic regression. Survival was not different between the groups on logistic regression or propensity score-matched analysis.

CONCLUSIONS

Tranexamic acid administration is not protective against pulmonary complications in penetrating trauma patients.

Trichinella spiralis alleviates LPS-induced acute lung injury by modulating the protective Th2 immune response

Sepsis is a disorder of immune regulation caused by pathogenic microorganisms. A large number of inflammatory factors and inflammatory mediators are released, resulting in systemic inflammatory response disorder and acute lung injury (ALI). Helminths infection activate Th2 cytokines and immunomodulatory pathways, which have the function of anti-infection effector molecules. The early infection of Trichinella spiralis (T. spiralis) was mainly intestinal phase. In this study, we explored the effect of intestinal phase infection of T. spiralis on LPS-induced ALI. Compared with control mice, the serum and lung tissues of T. spiralis infected mice had a significant decrease of Th1 inflammatory cytokines, a significant increase of Th2 anti-inflammatory cytokines, and a significant decrease of inflammatory cell infiltration in lung tissue. These results suggest that T. spiralis during the intestinal phase can act on distal organs (lung) and reduce LPS-induced lung inflammation, providing evidence for a potential new pathway for immune-mediated disease in helminths and a possible role for intestinal worms in the gut-lung axis.

Team-Based Care of the Patient Receiving Venovenous Extracorporeal Membrane Oxygenation

BACKGROUND

Guideline-based care of patients requiring extracorporeal membranous oxygenation, a form of life support for patients with refractory respiratory and/or cardiac failure, requires a multidisciplinary approach, yet a detailed description of the ideal integration of teams of physicians, acute care nurse practitioners, critical care nurses, and other disciplines is lacking in the literature.

OBJECTIVES

We sought to define team-based care of the patient receiving venovenous extracorporeal membrane oxygenation with an emphasis on the roles of the critical care nurse and the acute care nurse practitioner.

METHODS

A narrative literature review was conducted using the keywords or MeSH terms "team-based care" AND "ECMO" and "nurse practitioner" AND "ECMO." Electronic databases searched included PubMed, Cumulative Index for Nursing and Allied Health Literature, and PsycINFO.

RESULTS

Sixty-five articles met the search criteria, with 21% (n = 10) focusing on characteristics of team-based care for patients receiving ECMO. Articles describe the ideal composition of teams and their education and training, frameworks for the formation of ECMO teams, and aspects of communication. One article details the role of the acute care nurse practitioner in managing ECMO, but several omit or barely describe the nurse's role as a team member.

DISCUSSION

No articles were found that specifically define the key elements, structure, and dynamics of effective team-based care of the patient receiving ECMO. A holistic definition of team-based care of the patient receiving ECMO is proposed. Further research is warranted to correlate aspects of team-based care that optimize patient, team, and organization outcomes.

Receptor-Interacting Protein Kinase 3-Mediated Modulation of Endothelial Cell Necroptosis and Mitochondrial Dysfunction through AMPK/Drp1 Signaling Pathway: Insights into the Pathophysiological Mechanisms of Lipopolysaccharide-Induced Acute Lung Injury

Receptor-interacting protein 3 (Ripk3) plays a crucial part in acute lung injury (ALI) by regulating inflammation-induced endothelial damage in the lung tissue. The precise mechanisms through which Ripk3 contributes to the endothelial injury in ALI still remain uncertain. In the current research, we employed Ripk3-deficient (Ripk3-/-) mice to examine the role of Ripk3 in ALI progression, focusing on its effects on endothelial cells (ECs), mitochondrial damage and necroptosis. Our study observed significant Ripk3 upregulation in lipopolysaccharide- (LPS-) treated lung tissues, as well as in murine pulmonary microvascular endothelial cells (PMVECs). Ripk3 deletion improved lung tissue morphology, reduced inflammation, oxidative stress and endothelial dysfunction under LPS challenge. It also mitigated LPS-induced necroptosis and mitochondrial damage in PMVECs. Ripk3 upregulation suppressed the AMP-activated protein kinase (AMPK) pathway and activated Drp1-mediated mitochondrial fission, increasing mitochondrial permeability transition pore (mPTP) opening and PMVEC necroptosis. Conversely, Ripk3 deletion activated the AMPK/Drp1-mitochondrial fission pathway, preventing mPTP opening and PMVEC necroptosis in ALI. These findings demonstrated that Ripk3 promotes necroptosis through the AMPK/Drp1/mPTP opening pathway, identifying a potential therapeutic target for ALI treatment.

Toosendanin alleviates acute lung injury by reducing pulmonary vascular barrier dysfunction mediated by endoplasmic reticulum stress through mTOR

BACKGROUND

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are severe clinical conditions with limited treatment options. Toosendanin (TSN), a triterpenoid compound with anti-inflammatory effects, has unclear efficacy in ALI.

PURPOSE

This study aimed to evaluate TSN's protective effects on ALI and the related mechanisms.

METHODS

Lipopolysaccharide (LPS)-induced ALI models were developed in vivo and in vitro. Endothelial permeability was measured using Evans Blue dye; lipid reactive oxygen species (ROS) and apoptosis were assessed using flow cytometry. Malondialdehyde (MDA) and superoxide dismutase (SOD) levels were determined, and cell viability was measured. mRNA and protein expression were quantified using qRT-PCR and Western blotting. Network pharmacology and surface plasmon resonance were used to identify and validate TSN's targets.

RESULTS

TSN reduced endothelial permeability and LPS-induced ALI. It lowered ROS levels, lipid peroxidation, endoplasmic reticulum (ER) stress, and apoptosis, both in vitro and in vivo. Network pharmacology identified mTOR as a key target of TSN, and surface plasmon resonance analysis confirmed TSN's direct binding to mTOR, underscoring mTOR's role in TSN's protective effects against ALI. Western blotting showed that TSN inhibits mTOR and its phosphorylation. In vitro, the mTOR activator MHY1485 reversed TSN's protective effects, increasing ER stress, apoptosis, and endothelial permeability. In vivo, TSN and rapamycin synergistically protected against ALI.

CONCLUSION

This study is the first to demonstrate that TSN protects against ALI by targeting the mTOR pathway, regulating ER stress and apoptosis and mitigating endothelial damage. These findings suggest a novel approach for ALI treatment and underscore TSN's potential clinical value.

SIRT3 Deficiency Promotes Lung Endothelial Pyroptosis Through Impairing Mitophagy to Activate NLRP3 Inflammasome During Sepsis-Induced Acute Lung Injury

Acute lung injury (ALI) is a major cause of death in bacterial sepsis due to endothelial inflammation and endothelial permeability defects. Mitochondrial dysfunction is recognized as a key mediator in the pathogenesis of sepsis-induced ALI. Sirtuin 3 (SIRT3) is a histone protein deacetylase involved in preservation of mitochondrial function, which has been demonstrated in our previous study. Here, we investigated the effects of SIRT3 deficiency on impaired mitophagy to promote lung endothelial cells (ECs) pyroptosis during sepsis-induced ALI. We found that 3-TYP aggravated sepsis-induced ALI with increased lung ECs pyroptosis and enhanced NLRP3 activation. Mitochondrial reactive oxygen species (mtROS) and extracellular mitochondrial DNA (mtDNA) released from damaged mitochondria could be exacerbated in SIRT3 deficiency, which further elicit NLRP3 inflammasome activation in lung ECs during sepsis-induced ALI. Furthermore, Knockdown of SIRT3 contributed to impaired mitophagy via downregulating Parkin, which resulted in mitochondrial dysfunction. Moreover, pharmacological inhibition NLRP3 or restoration of SIRT3 attenuates sepsis-induced ALI and sepsis severity in vivo. Taken together, our results demonstrated SIRT3 deficiency facilitated mtROS production and cytosolic release of mtDNA by impaired Parkin-dependent mitophagy, promoting to lung ECs pyroptosis through the NLRP3 inflammasome activation, which providing potential therapeutic targets for sepsis-induced ALI.

Ghrelin may protect against vascular endothelial injury in Acute traumatic coagulopathy by mediating the RhoA/ROCK/MLC2 pathway

Ghrelin exerts widespread effects in several diseases, but its role and mechanism in Acute Traumatic Coagulopathy (ATC) are largely unknown. The effect of ghrelin on cell proliferation was examined using three assays: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), Lactate Dehydrogenase (LDH), and flow cytometry. The barrier function of the endothelial cells was evaluated using the Trans-Endothelial Electrical Resistance (TEER) and the endothelial permeability assay. An ATC mouse model was established to evaluate the in vivo effects of ghrelin. The Ras homolog family member A (RhoA) overexpression plasmid or adenovirus was used to examine the molecular mechanism of ghrelin. Ghrelin enhanced Human Umbilical Vein Endothelial Cells (HUVEC) proliferation and endothelial cell barrier function and inhibited HUVEC permeability damage in vitro. Additionally, ghrelin decreased the activated Partial Thromboplastin Time (aPTT) and Prothrombin Time (PT) in mice blood samples in the ATC mouse model. Ghrelin also improved the pathological alterations in postcava. Mechanistically, ghrelin acts through the RhoA/ Rho-associated Coiled-coil Containing Kinases (ROCK)/ Myosin Light Chain 2 (MLC2) pathway. Furthermore, the protective effects of ghrelin, both in vitro and in vivo, were reversed by RhoA overexpression. Our findings demonstrate that ghrelin may reduce vascular endothelial cell damage and endothelial barrier dysfunction by blocking the RhoA pathway, suggesting that ghrelin may serve as a potential therapeutic target for ATC treatment.

The role of vascularity and the fibrovascular interface in interstitial lung diseases

Interstitial lung disease (ILD) is a clinical term that refers to a diverse group of non-neoplastic lung diseases. This group includes idiopathic and secondary pulmonary entities that are often associated with progressive pulmonary fibrosis. Currently, therapeutic approaches based on specific structural targeting of pulmonary fibrosis are limited to nintedanib and pirfenidone, which can only slow down disease progression leading to a lower mortality rate. Lung transplantation is currently the only available curative treatment, but it is associated with high perioperative mortality. The pulmonary vasculature plays a central role in physiological lung function, and vascular remodelling is considered a hallmark of the initiation and progression of pulmonary fibrosis. Different patterns of pulmonary fibrosis commonly exhibit detectable pathological features such as morphomolecular changes, including intussusceptive and sprouting angiogenesis, vascular morphometry, broncho-systemic anastomoses, and aberrant angiogenesis-related gene expression patterns. Dynamic cellular interactions within the fibrovascular interface, such as endothelial activation and endothelial-mesenchymal transition, are also observed. This review aims to summarise the current clinical, radiological and pathological diagnostic algorithm for different ILDs, including usual interstitial pneumonia/idiopathic pulmonary fibrosis, non-specific interstitial pneumonia, alveolar fibroelastosis/pleuroparenchymal fibroelastosis, hypersensitivity pneumonitis, systemic sclerosis-related ILD and coronavirus disease 2019 injury. It emphasises an interdisciplinary clinicopathological perspective. Additionally, the review covers current therapeutic strategies and knowledge about associated vascular abnormalities.

Effects of innovative modular prone positioning tools in patients with acute respiratory distress syndrome due to COVID-19 during awake prone position: a prospective randomized controlled trial

OBJECTIVES

Our aim is to investigate the effects of a innovative modular prone positioning tools on patients with acute respiratory distress syndrome (ARDS) caused by COVID-19 during awake prone positioning (AW-PP).

METHODS

This prospective randomized controlled study initially enrolled 168 patients with COVID-19 due to ARDS. However, 92 were subsequently disqualified, leaving 76 patients who were randomly assigned to either the observation group (n = 38) or the control group (n = 38). The observation group utilized innovative modular prone positioning tools for non-invasive respiratory support (NIRS), while the control group used soft pillows for the same treatment. Data were collected on comfort levels, adverse events, and efficacy indicators. Additionally, the comfort, incidence of adverse events, and treatment efficacy in both groups were evaluated.

RESULTS

The observation group had shorter the daily duration spent on executing the AW-PP (2.74 ± 0.86 min vs. 4.64 ± 1.02 min, P < 0.001), longer the daily total AW-PP (8.52 ± 1.01 h vs. 6.03 ± 0.66 h, P < 0.001), longer the daily duration until the first position adjustment (59.89 ± 12.73 min vs. 36.57 ± 8.69 min, P < 0.001), and lower the daily frequency of position adjustments during the AW-PP (11.03 ± 2.67 vs. 17.95 ± 2.58, P < 0.001) in comparison with the control group. No significant differences were observed in intubation rates, mortality, the daily number of hours under HFNO and NIV, escalated to NIV from HFNO, and hospital length of stay between the groups (P > 0.05). However, the observation group experienced significantly fewer adverse events, including kinking NIRS circuit, pain, shortness of breath, dizziness, and pressure ulcers (P < 0.05).

CONCLUSION

Innovative modular prone positioning tools improved efficiency, comfort, and reduced adverse events during AW-PP but did not affect intubation rates or mortality.

Spontaneous Inflammation Resolution Inspired Nanoparticles Promote Neutrophil Apoptosis and Macrophage Efferocytosis for Acute Respiratory Distress Syndrome Treatment

During acute respiratory distress syndrome (ARDS), delayed apoptosis of neutrophils and impaired efferocytosis of macrophages constitute two critical limiting steps, leading to secondary inflammatory storm and posing a significant threat to human health. However, due to the failure of previous single target-centric treatments to effectively address these two limiting steps in controlling the inflammatory storm, no available therapies are approved for ARDS treatment. Herein, inspired by spontaneous inflammation resolution, two kinds of Apoptosis and Efferocytosis Restored Nanoparticles (AER NPs) are proposed to overcome these two limiting steps for counteracting severe inflammatory storm. For the first limiting step, neutrophil-targeted apoptosis-restored nanoparticles (AR NPs) accelerated the programmed apoptosis of inflammatory neutrophils. The resolution of the first limiting step facilitated the accumulation of macrophage-targeted and efferocytosis-restored nanoparticles (ER NPs), thereby restoring macrophage efferocytosis and alleviating the second limiting step. The results indicated that after sequential treatment with AER NPs, recruited neutrophils decreased to 13.86%, and macrophage efferocytosis increased to 563.24%. AER NPs promoted inflammation resolution and established a self-healing virtuous loop by addressing the two limiting steps, ultimately effectively treating ARDS. This work suggests that a strategy inspired by inflammation resolution holds promise as a potential approach for advancing inflammation therapy.

PNSC5325 prevents acute respiratory distress syndrome by alleviating inflammation and inhibiting extracellular matrix degradation of alveolar macrophages

BACKGROUND

Acute respiratory distress syndrome (ARDS) is characterized by severe inflammation and significant extracellular matrix (ECM) degradation in the lungs. Our prior research identified the CtBP2-p300-NF-κB (C-terminal-binding protein 2-histone acetyltransferase p300-nuclear factor kappa B) transcriptional complex as critical in ARDS by activating pro-inflammatory cytokine genes.

METHODS

An ARDS mouse model was established using intratracheal instillation of lipopolysaccharide (LPS). Small molecules that inhibit the CtBP2-p300 interaction were identified through AlphaScreen. RNA sequencing (RNA-Seq) was conducted to determine differential gene expression. Immunoprecipitation and co-immunoprecipitation analyzed protein interactions. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunoblotting detected gene and protein expression. Histological staining evaluated tissue damage.

RESULTS

Through AlphaScreen, two natural compounds, PNSC2477 and PNSC5325, were identified for their ability to inhibit the CtBP2-p300 interaction. While PNSC2477 demonstrated toxicity and was deemed unsuitable for further research, PNSC5325 exhibited minimal toxicity. PNSC5325 effectively inhibited the CtBP2-p300 interaction and reduced pro-inflammatory cytokine gene expression. RNA-Seq analysis of PNSC5325-treated cells indicated significant suppression of pro-inflammatory cytokine genes and matrix metalloproteinases (MMPs). Further molecular studies revealed that the CtBP2-p300 complex, in conjunction with activator protein 1 (AP1), activates MMP expression. PNSC5325 simultaneously suppressed both pro-inflammatory cytokines and MMPs by targeting the CtBP2-p300 complex. In LPS-injected mice, PNSC5325 administration significantly reduced ARDS incidence by inhibiting inflammatory and MMP genes.

CONCLUSION

These findings suggest that PNSC5325 protects against ARDS by inhibiting key inflammatory and ECM degradation pathways, highlighting its potential as a novel therapeutic agent for ARDS and paving the way for further clinical investigations.

Regulated Cell Death of Alveolar Macrophages in Acute Lung Inflammation: Current Knowledge and Perspectives

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a common and serious clinical lung disease characterized by extensive alveolar damage and inflammation leading to impaired gas exchange. Alveolar macrophages (AMs) maintain homeostatic properties and immune defenses in lung tissues. Several studies have reported that AMs are involved in and regulate ALI/ARDS onset and progression via different regulated cell death (RCD) programs, such as pyroptosis, apoptosis, autophagic cell death, and necroptosis. Notably, the effects of RCD in AMs in disease are complex and variable depending on the environment and stimuli. In this review, we provide a comprehensive perspective on how regulated AMs death impacts on ALI/ARDS and assess its potential in new therapeutic development. Additionally, we describe the crosstalk between different RCD types in ALI, and provide new perspectives for the treatment of ALI/ARDS and other severe lung diseases.

Aerosol Inhalation of Luteolin-7-O-Glucuronide Exerts Anti-Inflammatory Effects by Inhibiting NLRP3 Inflammasome Activation

Background: Luteolin-7-O-glucuronide (L7Gn) is a flavonoid isolated from numerous traditional Chinese herbal medicines that exerts anti-inflammatory effects. Previous research has revealed that aerosol inhalation is the most straightforward way of administration for the delivery of respiratory agents. Thus far, the impact of aerosol inhalation of L7Gn on lung inflammation and the underlying mechanisms remain unknown. Methods: The real-time particle size for L7Gn aerosol inhalation was detected by the Spraytec spray droplet size measurement system, including transmission and size diameters. The acute lung injury (ALI) rat model was induced by aerosol inhalation of LPS to evaluate the protective effect of L7Gn. The inhibitory effect of NLRP3 inflammasome activation assays was conducted in LPS-induced MH-S cells. Elisa, Western blotting, and RT-PCR were utilized to investigate the expression of NLRP3 inflammasome-relevant proteins and genes. Results: In this study, we found that inhalation of L7Gn aerosol significantly reduced pulmonary injury by inhibiting inflammatory infiltration and enhancing lung function. Meanwhile, the NLR family pyrin domain containing 3 (NLRP3) inflammasome was activated dramatically, accompanied by upregulated expression of IL-1β and IL-18, both in the ALI rat model and in LPS-induced MH-S cells. Moreover, L7Gn was found to significantly downregulate the expression of NLRP3, ASC, caspase-1, and cleaved caspase-1, which are critical components of the NLRP3 inflammasome, as well as the expression of IL-1β and IL-18. Conclusions: Based on our findings, L7Gn could exert anti-inflammatory effects by inhibiting NLRP3 inflammasome activation, which may emerge as potential therapeutic agents for the treatment of ALI.

Lung immune incompetency after mild peritoneal sepsis and its partial restoration by type 1 interferon: a mouse model study

BACKGROUND

Sepsis is commonly associated with acute respiratory distress syndrome (ARDS). Although the exaggerated inflammation may damage intact lung tissues, a percentage of patients with ARDS are reportedly immunocompromised, with worse outcomes. Herein, using a murine sepsis model, time-course immune reprogramming after sepsis was evaluated to explore whether the host is immunocompromised. Leukocyte kinetics in the lung tissue were evaluated in a male C57/BL6 mouse model of mild peritoneal sepsis induced by cecal ligation and puncture, with the survival rate exceeds 90%. Lung immune reactivity was evaluated by intratracheal instillation of lipopolysaccharide (LPS; 30 µg). Furthermore, the effect of interferon (IFN)-β in vivo and ex vivo was evaluated.

RESULTS

Four days after sepsis, the lung water content remained high, even among mice in clinical recovery. While monocytes and neutrophils gradually accumulated in the lung interstitium, the inflammatory cytokine/chemokine expression levels in the lungs continued to decline. Intratracheal LPS instillation induced more leukocyte trafficking and protein leakage into the alveoli in the septic lung, indicating more severe lung injury. However, LPS stimulation-associated mRNA expression of tnf, il6, ccl2, and cxcl1 was suppressed. Intra-alveolar expression of tumor necrosis factor (TNF)-α, interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, and keratinocyte-derived cytokine (KC) was also suppressed. Monocytes isolated from the lung tissue showed an impaired response in il6, ccl2, and cxcl1 to LPS. Systemic IFN-β restored the above impaired regulator function of monocytes, as did coculturing these cells from lung tissue with IFN-β.

CONCLUSIONS

Histologically accelerated inflammation and paradoxically suppressed immunological regulator signaling were observed in the early recovery phase of sepsis. This observation may provide a model for the immunologically irresponsive state that occurs in some patients with sepsis. Systemic IFN-β partly restored the post-septic immunocompromised state, indicating its therapeutic potential for the immunosuppressive state seen in some patients with sepsis/ARDS.

Isoliquiritigenin Exhibits Anti-Inflammatory Responses in Acute Lung Injury by Covalently Binding to the Myeloid Differentiation Protein-2 Domain

Acute lung injury (ALI), a systemic inflammatory response with high morbidity, lacks effective pharmacological therapies. Myeloid differentiation protein-2 (MD2) has emerged as a promising therapeutic target for ALI. Herein, we aimed to evaluate the ability of isoliquiritigenin (ISL), a natural flavonoid found in licorice as a novel MD2 inhibitor, to inhibit lipopolysaccharide (LPS)-induced ALI. We established a mouse ALI model and a RAW 264.7 cell injury model through LPS administration. Then, lung injury was assessed through histopathological examination, and the effects of ISL were evaluated using immunofluorescence, western blotting, reverse transcription-quantitative polymerase chain reaction, flow cytometry, and enzyme-linked immunosorbent assays. In addition, the interaction between ISL and MD2 was investigated through co-immunoprecipitation and LPS displacement assays. Molecular docking and liquid chromatography/mass spectrometry analyses were employed to predict the ISL-binding domain of MD2. We found that ISL covalently bound to the Cysteine 133 residue of MD2, disrupting the formation of the LPS/MD2/toll-like receptor 4 complex, and ISL significantly suppressed proinflammatory cytokine production and reactive oxygen species generation in LPS-induced RAW264.7 cells. Moreover, ISL significantly alleviated lung injury in LPS-induced mice, reducing pulmonary microvascular permeability, inflammatory cell infiltration, and inflammatory cytokine expression. The underlying mechanism of ISL involved the inhibition of nuclear factor kappa B and the p38 mitogen-activated protein kinase pathway. Our findings supported that MD2 is the direct target of ISL in mediating its anti-inflammatory response in vivo and in vitro, and it holds potential as a therapeutic candidate for treating ALI and other inflammatory diseases.

Exploration of key mechanisms underlying the therapeutic effects of AMD3100 on attenuating lipopolysaccharide-induced acute lung injury in mice

Context

AMD3100, a CXCR4 antagonist, has beneficial effects immaculate in the treatment of acute lung injury (ALI).

Objective

ALI is a severe inflammatory condition associated with poor prognosis and limited treatment options. AMD3100, has therapeutic effects that reduce ALI. Our study explored the regulatory mechanisms of AMD3100 in alleviating the injury of lipopolysaccharide (LPS)-induced ALI in mice.

Materials and Methods

Male ICR mice were randomly divided into control, LPS-treated, AMD3100-treated, and LPS + AMD3100-treatment groups. The histological changes of lung tissues from different groups were evaluated using hematoxylin and eosin staining. Lung injury was measured by ELISA and lung wet/dry ratio. Moreover, lung tissues from the four groups were subjected to transcriptome sequencing followed by differential expression, functional enrichment, protein-protein interaction (PPI) networks, and transcription factor analyses. The validation of mRNAs and protein levels were conducted with qRT-PCR and ELISA.

Results

Hematoxylin and eosin staining combined with the concentration of IL-1 and IL1-β and lung wet/dry ratios revealed that AMD3100 reduced the level of LPS-induced lung injury. Analysis of the transcriptome sequencing data identified 294 differentially expressed genes in the LPS-induced ALI mouse model. Based on the PPI network and module analysis, hub targets of AMD3100, such as Cxcl10 and Cxcl9, were identified in module 1, and hub targets, such as Cxcl12 and Cxcl1, were identified in module 2. Cxcl10 and Cxcl9 are involved in the Toll-like receptor signaling pathway, and Cxcl12 and Cxcl1 arae enriched in the nuclear factor-kappa B signaling pathway. Cxcl19, Cxcl10, and Cxcl1 are targeted by transcription factors like NF-κB. The validation of mRNAs and protein levels conducted by PCR and ELISA supported our transcriptome data.

Conclusions

Our findings indicate that AMD3100 may exhibit a therapeutic effect on LPS-induced ALI in mice by modulating multiple chemokines to inhibit the Toll-like receptor/nuclear factor-kappa B signaling pathway.

Quercetin: A Flavonoid with Potential for Treating Acute Lung Injury

In intensive care units, acute lung injury (ALI) is a syndrome that is frequently encountered. It is associated with a high rate of morbidity and mortality. Despite the extensive research conducted by the medical community on its treatment, no specific effective drugs have been identified. Quercetin is a natural flavonoid with many biological activities and pharmacological effects. Research indicates that Quercetin can modulate various targets and signaling pathways, inhibiting oxidative stress, inflammatory responses, ferroptosis, apoptosis, fibrosis, and bacterial and viral infections in ALI. This regulation suggests its potential therapeutic application for the condition. Currently, there is no comprehensive review addressing the application of Quercetin in the treatment of ALI. This paper begins with a classification of ALI, followed by a detailed summary of the mechanisms through which Quercetin may treat ALI to evaluate its potential as a novel therapeutic option.

Application of Macrophage Subtype Analysis in Acute Lung Injury/Acute Respiratory Distress Syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common critical illness. Supportive therapy is still the main strategy for ALI/ARDS. Macrophages are the predominant immune cells in the lungs and play a pivotal role in maintaining homeostasis, regulating metabolism, and facilitating tissue repair. During ALI/ARDS, these versatile cells undergo polarization into distinct subtypes with significant variations in transcriptional profiles, developmental trajectory, phenotype, and functionality. This review discusses developments in the analysis of alveolar macrophage subtypes in the study of ALI/ARDS, and the potential value of targeting new macrophage subtypes in the diagnosis, prognostic evaluation, and treatment of ALI/ARDS.

Lysophosphatidylcholine 14:0 Alleviates Lipopolysaccharide-Induced Acute Lung Injury via Protecting Alveolar Epithelial Barrier by Activation of Nrf2/HO-1 Pathway

Background

Acute lung injury (ALI) is characterized by diffuse alveolar injury and acute non-cardiac pulmonary edema, with high morbidity and mortality. Lysophosphatidylcholine 14:0 (LPC14:0) has anti-inflammatory and anti-oxidative effects in sepsis and bacteremia. We hypothesized that LPC14:0 could be a potential treatment for ALI. Therefore, the effects of LPC14:0 on lung epithelial cells and the underlying mechanism on ALI were investigated.

Methods

Lipopolysaccharide (LPS) was instilled intratracheally in vivo while the Murine Lung Epithelial-12 was stimulated by tert-butyl hydroperoxide (t-BHP) in vitro to induce the ALI model. In vivo, lung injury was evaluated by histopathological changes and pulmonary edema was assessed by wet/dry ratio. Evans blue infiltration in lung tissue, total protein content, total cell counts and inflammatory factors in bronchoalveolar lavage fluid were evaluated for alveolar permeability. In vitro, cell viability and cell death rate were assessed by cell counting kit-8 and Calcein-AM/PI stain respectively. The expression of ZO-1, Occludin, Nrf2, and HO-1 was evaluated by Western blot.

Results

LPC14:0 attenuated the LPS-stimulated lung injury and oxidative stress in vivo, and alleviated the t-BHP-induced cell damage in vitro. Moreover, LPC14:0 significantly inhibited the degradation of the tight junction proteins and activated the Nrf2/HO-1 signaling pathway both in vivo and in vitro. Mechanistically, ML385, the Nrf2 inhibitor, inhibited the protective effects of LPC14:0 on barrier function in vitro.

Conclusion

This study first demonstrated that LPC14:0 mitigated LPS-induced ALI and the destruction of tight junctions, at least in part through up-regulation of the Nrf2/HO-1 pathway.

Nanotherapy therapy for acute respiratory distress syndrome: a review

Acute respiratory distress syndrome (ARDS) is a complex and life-threatening disease characterized by severe respiratory failure. The lethality of ARDS remains alarmingly high, especially with the persistent ravages of coronavirus disease 2019 (COVID-19) in recent years. ARDS is one of the major complications of neocoronavirus pneumonia and the leading cause of death in infected patients. The large-scale outbreak of COVID-19 has greatly increased the incidence and mortality of ARDS. Despite advancements in our understanding of the causes and mechanisms of ARDS, the current clinical practice is still limited to the use of supportive medications to alleviate its progression. However, there remains a pressing need for effective therapeutic drugs to combat this devastating disease. In this comprehensive review, we discuss the commonly used therapeutic drugs for ARDS, including steroids, vitamin C, targeted inhibitors, and heparin. While these medications have shown some promise in managing ARDS, there is still a significant gap in the availability of definitive treatments. Moreover, we highlight the potential of nanocarrier delivery systems, such as liposomes, lipid nanoparticles, polymer nanoparticles, and inorganic nanoparticles, as promising therapeutic approaches for ARDS in the future. These innovative delivery systems have demonstrated encouraging results in early clinical trials and offer the potential for more targeted and effective treatment options. Despite the promising early results, further clinical trials are necessary to fully assess the efficacy and safety of nanotherapies for ARDS. Additionally, more in-depth research should be conducted to focus on the continuous development of precision therapies targeting different stages of ARDS development or different triggers. This will provide more ideas and rationale for the treatment of ARDS and ultimately lead to better patient outcomes.

Esketamine alleviates ferroptosis-mediated acute lung injury by modulating the HIF-1α/HO-1 pathway

BACKGROUND

Alveolar epithelial cell (AEC) ferroptosis contributes to the progression of acute lung injury (ALI). Esketamine (ESK) is a new clinical sedative, anesthetic, and analgesic drug that has attracted substantial attention in mental health research because of its antidepressant effects. However, the effects of ESK on ferroptosis-mediated ALI remain unclear.

OBJECTIVE

This study aimed to explore the protective effect of ESK on AEC ferroptosis in ALI and its potential molecular mechanism in vivo and in vitro.

METHODS

The antiferroptotic and anti-inflammatory effects of ESK were assessed in a mouse model of lipopolysaccharide (LPS)-induced ALI. In vitro, the epithelial cell lines MLE-12 and A549 were used to examine the underlying mechanism by which ESK regulates inflammation and ferroptosis.

RESULTS

ESK protected mice against LPS-induced ALI, significantly attenuated pathological changes in the lungs and decreased inflammation and ferroptosis. In vitro, ESK inhibited LPS-induced inflammation and ferroptosis in MLE-12 and A549 cells. Moreover, ferroptosis mediated inflammation in LPS-induced ALI in vivo and in vitro, and ESK decreased the LPS-induced inflammatory response by suppressing ferroptosis. ESK promoted the HIF-1α/HO-1 pathway in LPS-treated AECs and in the lung tissues of mice with LPS-induced ALI. Moreover, pretreatment with ESK and the HIF-1α stabilizer dimethyloxaloylglycine (DMOG) substantially attenuated lung injury and prevented changes in ferroptosis-related biochemical indicators, including glutathione (GSH) depletion, malondialdehyde (MDA) production and glutathione peroxidase 4 (GPX4) downregulation, in untreated LPS-induced mice but not in LPS-induced mice treated with the HO-1 inhibitor zinc protoporphyrin (ZNPP). Similar effects were observed in vitro in HO-1 siRNA-transfected A549 cells after LPS incubation but not in control siRNA-transfected cells.

CONCLUSION

ESK can inhibit ferroptosis-mediated lipid peroxidation by increasing the expression of HIF-1α/HO-1 pathway, highlighting the potential of ESK to treat LPS-induced ALI.