Acute respiratory distress syndrome

Shenfu injection targets the PI3K-AKT pathway to regulate autophagy and apoptosis in acute respiratory distress syndrome caused by sepsis

BACKGROUND

Sepsis is a life-threatening organ dysfunction caused by an exaggerated response to infection. In the lungs, one of the most susceptible organs, this can manifest as acute respiratory distress syndrome (ARDS). Shenfu (SF) injection is a prominent traditional Chinese medicine used to treat sepsis. However, the exact mechanism of its action has rarely been reported in the literature.

PURPOSE

In the present study, we detected the protective effect of SF injection on sepsis-induced ARDS and explored its underlying mechanism.

METHODS

We investigated the potential targets and regulatory mechanisms of SF injections using a combination of network pharmacology and RNA sequencing. This study was conducted both in vivo and in vitro using a mouse model of ARDS and lipopolysaccharide (LPS)-stimulated MLE-12 cells, respectively.

RESULTS

The results showed that SF injection could effectively inhibit inflammation, oxidative stress, and apoptosis to alleviate LPS-induced ARDS. SF inhibited the PI3K-AKT pathway, which controls autophagy and apoptosis. Subsequently, MLE-12 cells were treated with 3-methyladenine to assess its effects on autophagy and apoptosis. Additional experiments were conducted by adding rapamycin, an mTOR antagonist, or SC79, an AKT agonist, to investigate the effects of SF injection on autophagy, apoptosis, and the PI3K-AKT pathway.

CONCLUSION

Overall, we found that SF administration could enhance autophagic activity, reduce apoptosis, suppress inflammatory responses and oxidative stress, and inhibit the PI3K-AKT pathway, thus ameliorating sepsis-induced ARDS.

Resveratrol alleviates acute lung injury in mice by promoting Pink1/Parkin-related mitophagy and inhibiting NLRP3 inflammasome activation

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are characterized by rapid onset and widespread inflammation in the lungs, often leading to respiratory failure. These conditions can be triggered by various factors, resulting in a severe inflammatory response within the lungs. Resveratrol, a polyphenolic compound found in grapes and peanuts, is renowned for its potent antioxidative and anti-inflammatory properties. In this study, we investigated how resveratrol protects against lipopolysaccharide (LPS)-induced ALI in mice. We established mouse models of LPS-induced ALI and inflammation in bronchoalveolar lavage fluid (BALF) macrophages. Through histopathological examination, immunofluorescence, western blot, enzyme-linked immunosorbent assay (ELISA), and transmission electron microscopy (TEM), we assessed the impact of resveratrol on the activation of NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasomes and the process of mitophagy. Our findings indicate that resveratrol significantly mitigated the lung injury and inflammation caused by LPS. This was achieved by inhibiting the oligomerization of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and the activation of NLRP3 inflammasomes. Resveratrol also reduced the levels of IL-1β and IL-18 in serum and BALF, decreased caspase-1 expression, and diminished macrophage pyroptosis. Furthermore, it upregulated Pink1, Parkin, Beclin-1, Autophagy-Related 5 (Atg5), and Microtubule-Associated Proteins 1 A/1B Light Chain 3B (LC3B-II), thereby enhancing mitophagy. Conversely, mitophagy was inhibited by Pink1 siRNA. In conclusion, resveratrol ameliorated ALI in mice, potentially by inhibiting the activation of NLRP3 inflammasomes, activating the Pink1/Parkin pathway, and promoting mitophagy.

Red Blood Cell-Hitchhiking Delivery of Simvastatin to Relieve Acute Respiratory Distress Syndrome

Purpose

The purpose of this study is to address the high mortality and poor prognosis associated with Acute Respiratory Distress Syndrome (ARDS), conditions characterized by acute and progressive respiratory failure. The primary goal was to prolong drug circulation time, increase drug accumulation in the lungs, and minimize drug-related side effects.

Methods

Simvastatin (SIM) was used as the model drug in this study. Employing a red blood cell surface-loaded nanoparticle drug delivery technique, pH-responsive cationic nanoparticles loaded with SIM were non-covalently adsorbed onto the surface of red blood cells (RBC), creating a novel drug delivery system (RBC@SIM-PEI-PPNPs).

Results

The RBC@SIM-PEI-PPNPs delivery system effectively extended the drug's circulation time, providing an extended therapeutic window. Additionally, this method substantially improved the targeted accumulation of SIM in lung tissues, thereby enhancing the drug's efficacy in treating ARDS and impeding its progression to ARDS. Crucially, the system showed a reduced risk of adverse drug reactions.

Conclusion

RBC@SIM-PEI-PPNPs demonstrates promise in ARDS and ARDS treatment. This innovative approach successfully overcomes the limitations associated with SIM's poor solubility and low bioavailability, resulting in improved therapeutic outcomes and fewer drug-related side effects. This research holds significant clinical implications and highlights its potential for broader application in drug delivery and lung disease treatment.

S1PR3 inhibition protects against LPS-induced ARDS by inhibiting NF-κB and improving mitochondrial oxidative phosphorylation

BACKGROUND

Inflammation and endothelial barrier dysfunction are the major pathophysiological changes in acute respiratory distress syndrome (ARDS). Sphingosine-1-phosphate receptor 3 (S1PR3), a G protein-coupled receptor, has been found to mediate inflammation and endothelial cell (EC) integrity. However, the function of S1PR3 in ARDS has not been fully elucidated.

METHODS

We used a murine lipopolysaccharide (LPS)-induced ARDS model and an LPS- stimulated ECs model to investigate the role of S1PR3 in anti-inflammatory effects and endothelial barrier protection during ARDS.

RESULTS

We found that S1PR3 expression was increased in the lung tissues of mice with LPS-induced ARDS. TY-52156, a selective S1PR3 inhibitor, effectively attenuated LPS-induced inflammation by suppressing the expression of proinflammatory cytokines and restored the endothelial barrier by repairing adherens junctions and reducing vascular leakage. S1PR3 inhibition was achieved by an adeno-associated virus in vivo and a small interfering RNA in vitro. Both the in vivo and in vitro studies demonstrated that pharmacological or genetic inhibition of S1PR3 protected against ARDS by inhibiting the NF-κB pathway and improving mitochondrial oxidative phosphorylation.

CONCLUSIONS

S1PR3 inhibition protects against LPS-induced ARDS via suppression of pulmonary inflammation and promotion of the endothelial barrier by inhibiting NF-κB and improving mitochondrial oxidative phosphorylation, indicating that S1PR3 is a potential therapeutic target for ARDS.

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.

Integrated network pharmacology, molecular docking, and lipidomics to reveal the regulatory effect of Qingxuan Zhike granules on lipid metabolism in lipopolysaccharide-induced acute lung injury

Qingxuan Zhike granules (QXZKG), a traditional Chinese patent medication, has shown therapeutic potential against acute lung injury (ALI). However, the precise mechanism underlying its lung-protective effects requires further investigation. In this study, integrated network pharmacology, molecular docking, and lipidomics were used to elucidate QXZKG's regulatory effect on lipid metabolism in lipopolysaccharide-induced ALI. Animal experiments were conducted to substantiate the efficacy of QXZKG in reducing pro-inflammatory cytokines and mitigating pulmonary pathology. Network pharmacology analysis identified 145 active compounds that directly targeted 119 primary targets of QXZKG against ALI. Gene Ontology function analysis emphasized the roles of lipid metabolism and mitogen-activated protein kinase (MAPK) cascade as crucial biological processes. The MAPK1 protein exhibited promising affinities for naringenin, luteolin, and kaempferol. Lipidomic analysis revealed that 12 lipids showed significant restoration following QXZKG treatment (p < 0.05, FC >1.2 or <0.83). Specifically, DG 38:4, DG 40:7, PC O-40:8, TG 18:1_18:3_22:6, PI 18:2_20:4, FA 16:3, FA 20:3, FA 20:4, FA 22:5, and FA 24:5 were downregulated, while Cer 18:0;2O/24:0 and SM 36:1;2O/34:5 were upregulated in the QXZKG versus model groups. This study enhances our understanding of the active compounds and targets of QXZKG, as well as the potential of lipid metabolism in the treatment of ALI.

Hydrochloric Acid-Induced Acute Lung Injury Models: Dynamic Change and Quantitative Analysis of Modified Lung Ultrasound Scoring System and High-Resolution Computed Tomography

OBJECTIVE

Acute lung injury (ALI) has become a research hotspot due to its significant public health impact. To explore the value of the use of modified lung ultrasound (MLUS) scoring system for evaluating ALI using a rabbit model of ALI induced by hydrochloric acid (HCl) and investigate its correlation with high-resolution computed tomography (HRCT) and histopathological scores.

METHODS

Twenty New Zealand laboratory rabbits were randomly assigned to control group (N = 5) and 3 experimental groups (N = 5 each). The control group received instillation of physiological saline, while the 3 experimental groups received 2 mL/kg of different doses of HCl instillation (mild group: pH 1.5, moderate group: pH 1.2, and severe group: pH 1.0) through the trachea under ultrasound guidance. Pulmonary ultrasound (using Mindray Reason9 linear array probes with frequency of 6-15 mHz) and HRCT examinations were performed before modeling (0H) and at 1H, 2H, 4H, 8H, 12H after modeling. The experimental rabbits were sacrificed at 12H for examination of gross lung morphology and hematoxylin-eosin-stained histopathological sections. The correlation of MLUS scores with HRCT/histopathological scores was assessed.

RESULTS

All rabbits in the experimental groups showed oxygenation index PaO₂/FiO₂<300. Successful establishment of ALI model was proven by autopsy (successful modeling rate: 100%). The pathological damage increased with increase in HCl dosage. MLUS scores showed a positive correlation with HRCT scores/pathological severity. There was a strong positive correlation between MLUS scores and histopathological scores (r = 0.963, p < 0.05) as well as between HRCT scores and histopathological scores (r = 0.932, p < 0.05).

CONCLUSION

Transtracheal injection of different dosages of HCl under ultrasound guidance induced different degrees of ALI. The MLUS scoring system can be used for semiquantitative evaluation of ALI, and is suitable as a screening tool.

Prevalence, predictors, and outcomes of acute respiratory distress syndrome in severe stroke

OBJECTIVES

Patients with severe stroke are at high risk of developing acute respiratory distress syndrome (ARDS), but this severe complication was often under-diagnosed and rarely explored in stroke patients. We aimed to investigate the prevalence, early predictors, and outcomes of ARDS in severe stroke.

METHODS

This prospective study included consecutive patients admitted to neurological intensive care unit (neuro-ICU) with severe stroke, including acute ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage. The incidence of ARDS was examined, and baseline characteristics and severity scores on admission were investigated as potential early predictors for ARDS. The in-hospital mortality, length of neuro-ICU stay, the total cost in neuro-ICU, and neurological functions at 90 days were explored.

RESULTS

Of 140 patients included, 35 (25.0%) developed ARDS. Over 90% of ARDS cases occurred within 1 week of admission. Procalcitonin (OR 1.310 95% CI 1.005-1.707, P = 0.046) and PaO2/FiO2 on admission (OR 0.986, 95% CI 0.979-0.993, P < 0.001) were independently associated with ARDS, and high brain natriuretic peptide (OR 0.994, 95% CI 0.989-0.998, P = 0.003) was a red flag biomarker warning that the respiratory symptoms may be caused by cardiac failure rather than ARDS. ARDS patients had longer stays and higher expenses in neuro-ICU. Among patients with ARDS, 25 (62.5%) were moderate or severe ARDS. All the patients with moderate to severe ARDS had an unfavorable outcome at 90 days.

CONCLUSIONS

ARDS is common in patients with severe stroke, with most cases occurring in the first week of admission. Procalcitonin and PaO2/FiO2 on admission are early predictors of ARDS. ARDS worsens both short-term and long-term outcomes. The conflict in respiratory support strategies between ARDS and severe stroke needs to be further studied.

Identification and genetic validation of leukemia inhibitory factor super-enhancers in acute respiratory distress syndrome and lung cancer

Super-enhancers play prominent roles in driving robust pathological gene expression, but they are hidden in human genome at noncoding regions, making them difficult to explore. Leukemia inhibitory factor (LIF) is a multifunctional cytokine crucially involved in acute respiratory distress syndrome (ARDS) and lung cancer progression. However, the mechanisms governing LIF regulation in disease contexts remain largely unexplored. In this study, we observed elevated levels of LIF in the bronchoalveolar lavage fluid (BALF) of patients with sepsis-related ARDS compared to those with nonsepsis-related ARDS. Furthermore, both basal and LPS-induced LIF expression were under the control of super-enhancers. Through analysis of H3K27Ac ChIP-seq data, we pinpointed three potential super-enhancers (LIF-SE1, LIF-SE2, and LIF-SE3) located proximal to the LIF gene in cells. Notably, genetic deletion of any of these three super-enhancers using CRISPR-Cas9 technology led to a significant reduction in LIF expression. Moreover, in cells lacking these super-enhancers, both cell growth and invasion capabilities were substantially impaired. Our findings highlight the critical role of three specific super-enhancers in regulating LIF expression and offer new insights into the transcriptional regulation of LIF in ARDS and lung cancer.

Changes in Therapy and Outcome of Patients Requiring Veno-Venous Extracorporeal Membrane Oxygenation for COVID-19

BACKGROUND

 Coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome requiring veno-venous extracorporeal membrane oxygenation (vv-ECMO) is related with poor outcome, especially in Germany. We aimed to analyze whether changes in vv-ECMO therapy during the pandemic were observed and lead to changes in the outcome of vv-ECMO patients.

METHODS

 All patients undergoing vv-ECMO support for COVID-19 between 2020 and 2021 in a single center (n = 75) were retrospectively analyzed. Weaning from vv-ECMO and in-hospital mortality were defined as primary and peri-interventional adverse events as secondary endpoints of the study.

RESULTS

 During the study period, four infective waves were observed in Germany. Patients were assigned correspondingly to four study groups: ECMO implantation between March 2020 and September 2020: first wave (n = 11); October 2020 to February 2021: second wave (n = 23); March 2021 to July 2021: third wave (n = 25); and August 2021 to December 2021: fourth wave (n = 20). Preferred cannulation technique changed within the second wave from femoro-femoral to femoro-jugular access (p < 0.01) and awake ECMO was implemented. Mean ECMO run time increased by more than 300% from 10.9 ± 9.6 (first wave) to 44.9 ± 47.0 days (fourth wave). Weaning of patients was achieved in less than 20% in the first wave but increased to approximately 40% since the second one. Furthermore, we observed a continuous numerically decrease of in-hospital mortality from 81.8 to 57.9% (p = 0.61).

CONCLUSION

 Preference for femoro-jugular cannulation and awake ECMO combined with preexisting expertise and patient selection are considered to be associated with increased duration of ECMO support and numerically improved ECMO weaning and in-hospital mortality.

ANKRD22 aggravates sepsis-induced ARDS and promotes pulmonary M1 macrophage polarization

Acute respiratory distress syndrome (ARDS) is independently associated with a poor prognosis in patients with sepsis. Macrophage M1 polarization plays an instrumental role in this process. Therefore, the exploration of key molecules affecting acute lung injury and macrophage M1 polarization may provide therapeutic targets for the treatment of septic ARDS. Here, we identified that elevated levels of Ankyrin repeat domain-containing protein 22 (ANKRD22) were associated with poor prognosis and more pronounced M1 macrophage polarization in septic patients by analyzing high-throughput data. ANKRD22 expression was also significantly upregulated in the alveolar lavage fluid, peripheral blood, and lung tissue of septic ARDS model mice. Knockdown of ANKRD22 significantly attenuated acute lung injury in mice with sepsis-induced ARDS and reduced the M1 polarization of lung macrophages. Furthermore, deletion of ANKRD22 in macrophages inhibited M1 macrophage polarization and reduced levels of phosphorylated IRF3 and intracellular interferon regulatory factor 3 (IRF3) expression, while re-expression of ANKRD22 reversed these changes. Further experiments revealed that ANKRD22 promotes IRF3 activation by binding to mitochondrial antiviral-signaling protein (MAVS). In conclusion, these findings suggest that ANKRD22 promotes the M1 polarization of lung macrophages and exacerbates sepsis-induced ARDS.

A comprehensive review of natural product-derived compounds acting on P2X7R: The promising therapeutic drugs in disorders

BACKGROUND

The P2X7 receptor (P2X7R) is known to play a significant role in regulating various pathological processes associated with immune regulation, neuroprotection, and inflammatory responses. It has emerged as a potential target for the treatment of diseases. In addition to chemically synthesized small molecule compounds, natural products have gained attention as an important source for discovering compounds that act on the P2X7R.

PURPOSE

To explore the research progress made in the field of natural product-derived compounds that act on the P2X7R.

METHODS

The methods employed in this review involved conducting a thorough search of databases, include PubMed, Web of Science and WIKTROP, to identify studies on natural product-derived compounds that interact with P2X7R. The selected studies were then analyzed to categorize the compounds based on their action on the receptor and to evaluate their therapeutic applications, chemical properties, and pharmacological actions.

RESULTS

The natural product-derived compounds acting on P2X7R can be classified into three categories: P2X7R antagonists, compounds inhibiting P2X7R expression, and compounds regulating the signaling pathway associated with P2X7R. Moreover, highlight the therapeutic applications, chemical properties and pharmacological actions of these compounds, and indicate areas that require further in-depth study. Finally, discuss the challenges of the natural products-derived compounds exploration, although utilizing compounds from natural products for new drug research offers unique advantages, problems related to solubility, content, and extraction processes still exist.

CONCLUSION

The detailed information in this review will facilitate further development of P2X7R antagonists and potential therapeutic strategies for P2X7R-associated disorders.

Exploring immune-related pathogenesis in lung injury: Providing new insights Into ALI/ARDS

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) represent a significant global burden of morbidity and mortality, with lung injury being the primary cause of death in affected patients. The pathogenesis of lung injury, however, remains a complex issue. In recent years, the role of the immune system in lung injury has attracted extensive attention worldwide. Despite advancements in our understanding of various lung injury subtypes, significant limitations persist in both prevention and treatment. This review investigates the immunopathogenesis of ALI/ARDS, aiming to elucidate the pathological processes of lung injury mediated by dendritic cells (DCs), natural killer (NK) cells, phagocytes, and neutrophils. Furthermore, the article expounds on the critical contributions of gut microbiota, inflammatory pathways, and cytokine storms in the development of ALI/ARDS.

NETs induce ferroptosis of endothelial cells in LPS-ALI through SDC-1/HS and downstream pathways

BACKGROUND

Extracellular neutrophil extracellular traps (NETs) play an important role in acute lung injury (ALI), but their mechanisms are still unclear. The aim of this study is to explore the effects of NETs on endothelial glycocalyx/HGF/cMET pathway and ferroptosis in ALI and elucidate their potential mechanisms.

METHODS

Plasma was collected from healthy and sepsis patients to test for differences in neutrophil elastase (NE) expression of NETs components. In addition, LPS-ALI mice and endothelial cell injury models were established, and NETs were disrupted by siPAD4 (a driver gene for NETs) and sivelestat (an inhibitor of the NETs component) in the mice and by sivelestat in the endothelial cell injury models, and the effects of NETs on the SDC-1/HS/HGF/cMET pathway were studied. To verify the relationship between NETs and ferroptosis, Fer1, a ferroptosis inhibitor, was added as a positive control to observe the effect of NETs on ferroptosis indicators.

RESULTS

The expression level of NE was significantly higher in the plasma of sepsis patients. In ALI mice, intervention in the generation of NETs reduced pulmonary vascular permeability, protected the integrity of SDC-1/HS and promoted the downstream HGF/cMET pathway. In addition, sivelestat also improved the survival rate of mice, decreased the serious degree of ferroptosis. In the endothelial cells, the results were consistent with those of the ALI mice.

CONCLUSION

The study indicates that inhibiting the production of NETs can protect the normal conduction of the SDC-1/HS/HGF/cMET signalling pathway and reduce the severity of ferroptosis.

Acute lung injury: a view from the perspective of necroptosis

BACKGROUND

ALI/ARDS is a syndrome of acute onset characterized by progressive hypoxemia and noncardiogenic pulmonary edema as the primary clinical manifestations. Necroptosis is a form of programmed cell necrosis that is precisely regulated by molecular signals. This process is characterized by organelle swelling and membrane rupture, is highly immunogenic, involves extensive crosstalk with various cellular stress mechanisms, and is significantly implicated in the onset and progression of ALI/ARDS.

METHODS

The current body of literature on necroptosis and ALI/ARDS was thoroughly reviewed. Initially, an overview of the molecular mechanism of necroptosis was provided, followed by an examination of its interactions with apoptosis, pyroptosis, autophagy, ferroptosis, PANOptosis, and NETosis. Subsequently, the involvement of necroptosis in various stages of ALI/ARDS progression was delineated. Lastly, drugs targeting necroptosis, biomarkers, and current obstacles were presented.

CONCLUSION

Necroptosis plays an important role in the progression of ALI/ARDS. However, since ALI/ARDS is a clinical syndrome caused by a variety of mechanisms, we emphasize that while focusing on necroptosis, it may be more beneficial to treat ALI/ARDS by collaborating with other mechanisms.

Kaempferol mitigates sepsis-induced acute lung injury by modulating the SphK1/ S1P/ SIPR1/ MLC2 signaling pathway to restore the integrity of the pulmonary endothelial cell barrier

Sepsis-induced acute lung injury (SALI) is the common complication of sepsis, resulting in high incidence and mortality rates. The primary pathogenesis of SALI is the interplay between acute inflammation and endothelial barrier damage. Studies have shown that kaempferol (KPF) has anti-sepsis properties. Sphingosine kinase 1 (Sphk1)/sphingosine-1-phosphate (S1P) signaling pathway's significance in acute lung damage and S1P Receptor 1 (S1PR1) agonists potential in myosin light chain 2 (MLC2) phosphorylation are documented. Whether KPF can regulate the SphK1/S1P/SIPR1/MLC2 signaling pathway to protect the lung endothelial barrier remains unclear. This study investigates the KPF's therapeutic effects and molecular mechanisms in repairing endothelial cell barrier damage in both LPS-induced sepsis mice and human umbilical vein endothelial cells (HUVECs). KPF significantly reduced lung tissue damage and showed anti-inflammatory effects by decreasing IL-6 and TNF-α synthesis in the sepsis mice model. Further, KPF administration can reduce the high permeability of the LPS-induced endothelial cell barrier and alleviate lung endothelial cell barrier injury. Mechanistic studies showed that KPF pretreatment can suppress MLC2 hyperphosphorylation and decrease SphK1, S1P, and S1PR1 levels. The SphK1/S1P/S1PR1/MLC2 signaling pathway controls the downstream proteins linked to endothelial barrier damage, and the Western blot (WB) showed that KPF raised the protein levels. These proteins include zonula occludens (ZO)-1, vascular endothelial (VE)-cadherin and Occludin. The present work revealed that in mice exhibiting sepsis triggered by LPS, KPF strengthened the endothelial barrier and reduced the inflammatory response. The SphK1/S1P/S1PR1/MLC2 pathway's modulation is the mechanism underlying this impact.

HMGB1 promotes neutrophil PD-L1 expression through TLR2 and mediates T cell apoptosis leading to immunosuppression in sepsis

Neutrophils and T lymphocytes are closely related to occurrence of immunosuppression in sepsis. Studies have shown that neutrophil apoptosis decreases and T lymphocyte apoptosis increases in sepsis immunosuppression, but the specific mechanism involved remains unclear. In the present study, we found Toll-like Receptor 2 (TLR2) and programmed death-ligand 1 (PD-L1) were significantly activated in bone marrow neutrophils of wild-type mice after LPS treatment and that they were attenuated by treatment with C29, an inhibitor of TLR2. PD-L1 activation inhibits neutrophil apoptosis, whereas programmed death protein 1 (PD-1)activation promotes apoptosis of T lymphocytes, which leads to immunosuppression. Mechanistically, when sepsis occurs, pro-inflammatory factors and High mobility group box-1 protein (HMGB1) passively released from dead cells cause the up-regulation of PD-L1 through TLR2 on neutrophils. The binding of PD-L1 and PD-1 on T lymphocytes leads to increased apoptosis of T lymphocytes and immune dysfunction, eventually resulting in the occurrence of sepsis immunosuppression. In vivo experiments showed that the HMGB1 inhibitor glycyrrhizic acid (GA) and the TLR2 inhibitor C29 could inhibit the HMGB1/TLR2/PD-L1 pathway, and improving sepsis-induced lung injury. In summary, this study shows that HMGB1 regulates PD-L1 and PD-1 signaling pathways through TLR2, which leads to immunosuppression.

Identifying novel clinical phenotypes of acute respiratory distress syndrome using trajectories of daily fluid balance: a secondary analysis of randomized controlled trials

BACKGROUND

Previously identified phenotypes of acute respiratory distress syndrome (ARDS) could not reveal the dynamic change of phenotypes over time. We aimed to identify novel clinical phenotypes in ARDS using trajectories of fluid balance, to test whether phenotypes respond differently to different treatment, and to develop a simplified model for phenotype identification.

METHODS

FACTT (conservative vs liberal fluid management) trial was classified as a development cohort, joint latent class mixed models (JLCMMs) were employed to identify trajectories of fluid balance. Heterogeneity of treatment effect (HTE) for fluid management strategy across phenotypes was investigated. We also constructed a parsimonious probabilistic model using baseline data to predict the fluid trajectories in the development cohort. The trajectory groups and the probabilistic model were externally validated in EDEN (initial trophic vs full enteral feeding) trial.

RESULTS

Using JLCMM, we identified two trajectory groups in the development cohort: Class 1 (n = 758, 76.4% of the cohort) had an early positive fluid balance, but achieved negative fluid balance rapidly, and Class 2 (n = 234, 24.6% of the cohort) was characterized by persistent positive fluid balance. Compared to Class 1 patients, patients in Class 2 had significantly higher 60-day mortality (53.5% vs. 17.8%, p < 0.001), and fewer ventilator-free days (0 vs. 20, p < 0.001). A significant HTE between phenotypes and fluid management strategies was observed in the FACTT. An 8-variables model was derived for phenotype assignment.

CONCLUSIONS

We identified and validated two novel clinical trajectories for ARDS patients, with both prognostic and predictive enrichment. The trajectories of ARDS can be identified with simple classifier models.

Exploring the lung-gut direction of the gut-lung axis in patients with ARDS

Acute respiratory distress syndrome (ARDS) represents a life-threatening inflammatory reaction marked by refractory hypoxaemia and pulmonary oedema. Despite advancements in treatment perspectives, ARDS still carries a high mortality rate, often due to systemic inflammatory responses leading to multiple organ dysfunction syndrome (MODS). Indeed, the deterioration and associated mortality in patients with acute lung injury (LI)/ARDS is believed to originate alongside respiratory failure mainly from the involvement of extrapulmonary organs, a consequence of the complex interaction between initial inflammatory cascades related to the primary event and ongoing mechanical ventilation-induced injury resulting in multiple organ failure (MOF) and potentially death. Even though recent research has increasingly highlighted the role of the gastrointestinal tract in this process, the pathophysiology of gut dysfunction in patients with ARDS remains mainly underexplored. This review aims to elucidate the complex interplay between lung and gut in patients with LI/ARDS. We will examine various factors, including systemic inflammation, epithelial barrier dysfunction, the effects of mechanical ventilation (MV), hypercapnia, and gut dysbiosis. Understanding these factors and their interaction may provide valuable insights into the pathophysiology of ARDS and potential therapeutic strategies to improve patient outcomes.

Pulmonary drug delivery devices and nanosystems as potential treatment strategies for acute respiratory distress syndrome (ARDS)

Despite advances in drug delivery technologies, treating acute respiratory distress syndrome (ARDS) is challenging due to pathophysiological barriers such as lung injury, oedema fluid build-up, and lung inflammation. Active pharmaceutical ingredients (API) can be delivered directly to the lung site of action with the use of aerosol-based drug delivery devices, and this circumvents the hepatic first-pass effect and improves the bioavailability of drugs. This review discusses the various challenges and barriers for pulmonary drug delivery, current interventions for delivery, considerations for effective drug delivery, and the use of nanoparticle drug delivery carriers as potential strategies for delivering therapeutics in ARDS. Nanosystems have the added benefit of entrapping drugs, increase pulmonary drug bioavailability, and using biocompatible and biodegradable excipients that can facilitate targeted and/or controlled delivery. These systems provide an alternative to existing conventional systems. An effective way to deliver drugs for the treatment of ARDS can be by using colloidal systems that are aerosolized or inhaled. Drug distribution to the deeper pulmonary tissues is necessary due to the significant endothelial cell destruction that is prevalent in ARDS. The particle size of nanoparticles (<0.5 μm) makes them ideal candidates for treating ARDS as they can reach the alveoli. A look into the various potential benefits and limitations of nanosystems used for other lung disorders is also considered to indicate how they may be useful for the potential treatment of ARDS.

Melatonin alleviates septic ARDS by inhibiting NCOA4-mediated ferritinophagy in alveolar macrophages

Ferroptosis is a novel form of programmed cell death which can exacerbate lung injury in septic acute respiratory distress syndrome (ARDS). Alveolar macrophages, crucial innate immune cells, play a pivotal role in the pathogenesis of ARDS. Ferritinophagy is a process of ferritin degradation mediated by nuclear receptor coactivator 4 (NCOA4) which releases large amounts of iron ions thus promoting ferroptosis. Recent evidence revealed that inhibiting macrophage ferroptosis can effectively attenuate pulmonary inflammatory injury. Melatonin (MT), an endogenous neurohormone, has antioxidant and anti-inflammatory effects and can reduce septic ARDS. However, it is not clear whether MT's pulmonary protective effect is related to the inhibition of macrophage ferritinophagy. Our in vitro experiments demonstrated that MT decreased intracellular malondialdehyde (MDA), Fe2+, and lipid peroxidation levels, increased glutathione (GSH) levels and cell proliferation, and upregulated glutathione peroxidase 4 (GPX4) and ferritin heavy chain 1 (FTH1) protein levels in LPS-treated macrophages. Mechanistically, the antiferroptotic effect of MT on LPS-treated macrophages was significantly compromised by the overexpression of NCOA4. Our in vivo experiments revealed that MT alleviated the protein expression of NCOA4 and FTH1 in the alveolar macrophages of septic mice. Furthermore, MT improved lipid peroxidation and mitigated damage in alveolar macrophages and lung tissue, ultimately increasing the survival rates of septic mice. These findings indicate that MT can inhibit ferroptosis in an NCOA4-mediated ferritinophagy manner, thereby ameliorating septic ARDS.

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.

Rosmarinic acid alleviates septic acute respiratory distress syndrome in mice by suppressing the bronchial epithelial RAS-mediated ferroptosis

Activating angiotensin-converting enzyme 2 (ACE2) is an important player in the pathogenesis of septic-related acute respiratory distress syndrome (ARDS). Rosmarinic acid (RA) as a prominent polyphenolic secondary metabolite derived from Rosmarinus officinalis modulates ACE2 in sepsis remains unclear, although its impact on ACE inhibition and septic-associated lung injury has been explored. The study investigated the ACE2 expression in lipopolysaccharide (LPS)-induced lungs in mice and BEAS2B cells. Additionally, molecular docking, protein-protein interaction (PPI) network analysis, and western blotting were employed to predict and evaluate the molecular mechanism of RA on LPS-induced ferroptosis in vivo and in vitro. LPS-induced glutathione peroxidase 4 (GPX4) downregulation, ACE/ACE2 imbalance, and alteration of frequency of breathing (BPM), minute volume (MV), and the expiratory flow at 50% expired volume (EF50) were reversed by captopril pretreatment in vitro and in vivo. RA notably inhibited the infiltration into the lungs of neutrophils and monocytes with increased amounts of GPX4 and ACE2 proteins, lung function improvement, and decreased inflammatory cytokines levels and ER stress in LPS-induced ARDS in mice. Molecular docking showed RA was able to interact with ACE and ACE2. Moreover, combined with different pharmacological inhibitors to block ACE and ferroptosis, RA still significantly inhibited inflammatory cytokines Interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and C-X-C motif chemokine 2 (CXCL2) levels, as well as improved lung function, and enhanced GPX4 expression. Particularly, the anti-ferroptosis effect of RA in LPS-induced septic ARDS is RAS-dependent.

Predictors associated with successful weaning of veno-venous extracorporeal membrane oxygenation and mortality in adult patients with severe acute lung failure: Protocol of a pooled data analysis of cohort studies

BACKGROUND

Severe acute lung failure (ALF) often necessitates veno-venous extracorporeal membrane oxygenation (VV-ECMO), where identifying predictors of weaning success and mortality remains crucial yet challenging. The study aims to identify predictors of weaning success and mortality in adults undergoing VV-ECMO for severe ALF, a gap in current clinical knowledge.

METHODS AND ANALYSIS

PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials will be searched for cohort studies examining the predictive factors of successful weaning and mortality in adult patients on VV-ECMO due to severe ALF. Risk of bias assessment will be conducted using the Newcastle-Ottawa scale for each included study. The primary outcomes will be successful weaning from VV-ECMO and all-cause mortality. Between-study heterogeneity will be evaluated using the I2 statistic. Sensitivity, subgroup, and meta-regression analyses will be performed to ascertain potential sources of heterogeneity and assess the robustness of our results. We will use the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) tool to recommend the level of evidence.

DISCUSSION

This study seeks to provide clinically significant insights into predictors for weaning and mortality during VV-ECMO treatment for ALF, aiming to support clinical decisions and potentially influence health policy, thereby improving patient outcomes.

ETHICS AND DISSEMINATION

Given the absence of direct engagement with human subjects or access to personal medical records, ethical approval for this study is deemed unnecessary. The study findings will be shared at a scientific conference either at the global or national level. Alternatively, the results will be presented for publication in a rigorously peer-reviewed journal regarding critical care medicine.

Ethyl pyruvate ameliorates acute respiratory distress syndrome in mice

Acute respiratory distress syndrome (ARDS) became a focus of intensive research due to its death toll during the Covid-19 pandemic. An uncontrolled and excessive inflammatory response mediated by proinflammatory molecules such as high mobility group box protein 1 (HMGB1), IL-6, and TNF mounts as a response to infection. In this study, ethyl pyruvate (EP), a known inhibitor of HMGB1, was tested in the model of murine ARDS induced in C57BL/6 mice by intranasal administration of polyinosinic:polycytidylic acid (poly(I:C)). Intraperitoneal administration of EP ameliorated the ARDS-related histopathological changes in the lungs of poly(I:C)-induced ARDS and decreased numbers of immune cells in the lungs, broncho-alveolar lavage fluid and draining lymph nodes (DLN). Specifically, fewer CD8+ T cells and less activated CD4+ T cells were observed in DLN. Consequently, the lungs of EP-treated animals had fewer damage-inflicting CD8+ cells and macrophages. Additionally, the expression and production of proinflammatory cytokines, IL-17, IFN-γ and IL-6 were downregulated in the lungs. The expression of chemokine CCL5 which recruits immune cells into the lungs was also reduced. Finally, EP downregulated the expression of HMGB1 in the lungs. Our results imply that EP should be further evaluated as a potential candidate for ARDS therapy.

Caspase-3/Gasdermin E-mediated pyroptosis contributes to Ricin toxin-induced inflammation

Ricin toxin (RT) is highly cytotoxic and can release a considerable amount of pro-inflammatory factors due to depurination, causing excessive inflammation that may aggravate the harm to the body. Pyroptosis, a type of gasdermin-mediated cell death, is a contributor to the exacerbation of inflammation. Accumulating evidence indicate that pyroptosis plays a significant role in the pathogen infection and tissue injury, suggesting a potential correlation between pyroptosis and RT-induced inflammation. Here, we aim to demonstrate this correlation and explore its molecular mechanisms. Results showed that RT triggers mouse alveolar macrophage MH-S cells pyroptosis by activating caspase-3 and cleaving Gasgermin E (GSDME). In contrast, inhibition of caspase-3 with Z-DEVD-FMK (inhibitor of caspase-3) or knockdown of GSDME attenuates this process, suggesting the essential role of caspase-3/GSDME-mediated pyroptosis in contributing to RT-induced inflammation. Collectively, our study enhances our understanding of a novel mechanism of ricin cytotoxicity, which may emerge as a potential target in immunotherapy to control the RT-induced inflammation.

Establishment of a Predictive Model for Acute Respiratory Distress Syndrome in Patients with Bacterial Pneumonia

Background

Community-acquired pneumonia (CAP) is a global health concern due to its high rates of morbidity and mortality. Bacterial pathogens are common causes of CAP. It is one of the most common causes of acute respiratory distress syndrome (ARDS), a common severe respiratory system manifestation threatening human health. This study aimed to establish a predictive model for ARDS in patients with bacterial pneumonia, which was conducive to early identification of the occurrence and effective prevention of ARDS.

Methods

We collected the clinical data of hospitalized patients with bacterial pneumonia in Affiliated Huzhou Hospital of Zhejiang University School of Medicine from January 2022 to November 2022. The independent risk factors for ARDS in patients with bacterial pneumonia were determined by univariate and multivariate binary logistic regression analyses. The nomogram was constructed to display the predictive model, and the receiver-operating characteristic curve was plotted to evaluate the predictive value of ARDS.

Results

This study included 254 patients with bacterial pneumonia, of which 114 developed ARDS. The multivariate logistic regression analysis revealed age [odds ratio (OR) = 1.041, P = 0.003], heart rate (OR = 1.020, P = 0.028), lymphocyte count (OR = 0.555, P = 0.033), white blood cell count (OR = 1.062, P = 0.033), bilateral lung lesions (OR = 7.352, P = 0.011) and pleural effusion (OR = 2.512, P = 0.002) as the independent risk factors for ARDS. The predictive model was constructed based on the six independent factors, which was valuable in predicting ARDS with area under the curve of 0.794.

Conclusion

The predictive model was beneficial to evaluate the disease progression in patients with bacterial pneumonia and identify ARDS. Further, our nomogram might help doctors predict the incidence of ARDS and conduct treatment as early as possible.

LPS-induced monocarboxylate transporter-1 inhibition facilitates lactate accumulation triggering epithelial-mesenchymal transformation and pulmonary fibrosis

The epithelial-mesenchymal transformation (EMT) process of alveolar epithelial cells is recognized as involved in the development of pulmonary fibrosis. Recent evidence has shown that lipopolysaccharide (LPS)-induced aerobic glycolysis of lung tissue and elevated lactate concentration are associated with the pathogenesis of sepsis-associated pulmonary fibrosis. However, it is uncertain whether LPS promotes the development of sepsis-associated pulmonary fibrosis by promoting lactate accumulation in lung tissue, thereby initiating EMT process. We hypothesized that monocarboxylate transporter-1 (MCT1), as the main protein for lactate transport, may be crucial in the pathogenic process of sepsis-associated pulmonary fibrosis. We found that high concentrations of lactate induced EMT while moderate concentrations did not. Besides, we demonstrated that MCT1 inhibition enhanced EMT process in MLE-12 cells, while MCT1 upregulation could reverse lactate-induced EMT. LPS could promote EMT in MLE-12 cells through MCT1 inhibition and lactate accumulation, while this could be alleviated by upregulating the expression of MCT1. In addition, the overexpression of MCT1 prevented LPS-induced EMT and pulmonary fibrosis in vivo. Altogether, this study revealed that LPS could inhibit the expression of MCT1 in mouse alveolar epithelial cells and cause lactate transport disorder, which leads to lactate accumulation, and ultimately promotes the process of EMT and lung fibrosis.

Endothelial ERG programs neutrophil transcriptome for sustained anti-inflammatory vascular niche

Neutrophils (PMNs) reside as a marginated pool within the vasculature, ready for deployment during infection. However, how endothelial cells (ECs) control PMN extravasation and activation to strengthen tissue homeostasis remains ill-defined. Here, we found that the vascular ETS-related gene (ERG) is a generalized mechanism regulating PMN activity in preclinical tissue injury models and human patients. We show that ERG loss in ECs rewired PMN-transcriptome, enriched for genes associated with the CXCR2-CXCR4 signaling. Rewired PMNs compromise mice survival after pneumonia and induced lung vascular inflammatory injury following adoptive transfer into naïve mice, indicating their longevity and inflammatory activity memory. Mechanistically, EC-ERG restricted PMN extravasation and activation by upregulating the deubiquitinase A20 and downregulating the NFκB-IL8 cascade. Rescuing A20 in EC-Erg -/- endothelium or suppressing PMN-CXCR2 signaling rescued EC control of PMN activation. Findings deepen our understanding of EC control of PMN-mediated inflammation, offering potential avenues for targeting various inflammatory diseases.

Highlights

ERG regulates trans-endothelial neutrophil (PMN) extravasation, retention, and activationLoss of endothelial (EC) ERG rewires PMN-transcriptomeAdopted transfer of rewired PMNs causes inflammation in a naïve mouse ERG transcribes A20 and suppresses CXCR2 function to inactivate PMNs.

In brief/blurb

The authors investigated how vascular endothelial cells (EC) control polymorphonuclear neutrophil (PMN) extravasation, retention, and activation to strengthen tissue homeostasis. They showed that EC-ERG controls PMN transcriptome into an anti-adhesive and anti-inflammatory lineage by synthesizing A20 and suppressing PMNs-CXCR2 signaling, defining EC-ERG as a target for preventing neutrophilic inflammatory injury.

Cerebral hemodynamics and optic nerve sheath diameter acquired via neurosonology in critical patients with severe coronavirus disease: experience of a national referral hospital in Peru

Aim

We aimed to describe the neurosonological findings related to cerebral hemodynamics acquired using transcranial Doppler and to determine the frequency of elevated ICP by optic nerve sheath diameter (ONSD) measurement in patients with severe coronavirus disease (COVID-19) hospitalized in the intensive care unit of a national referral hospital in Peru.

Methods

We included a retrospective cohort of adult patients hospitalized with severe COVID-19 and acute respiratory failure within the first 7 days of mechanical ventilation under deep sedoanalgesia, with or without neuromuscular blockade who underwent ocular ultrasound and transcranial Doppler. We determine the frequency of elevated ICP by measuring the diameter of the optic nerve sheath, choosing as best cut-off value a diameter equal to or >5.8 mm. We also determine the frequency of sonographic patterns obtained by transcranial Doppler. Through insonation of the middle cerebral artery. Likewise, we evaluated the associations of clinical, mechanical ventilator, and arterial blood gas variables with ONSD ≥5.8 mm and pulsatility index (PI) ≥1.1. We also evaluated the associations of hemodynamic findings and ONSD with mortality the effect size was estimated using Poisson regression models with robust variance.

Results

This study included 142 patients. The mean age was 51.39 ± 13.3 years, and 78.9% of patients were male. Vasopressors were used in 45.1% of patients, and mean arterial pressure was 81.87 ± 10.64 mmHg. The mean partial pressure of carbon dioxide (PaCO2) was elevated (54.08 ± 16.01 mmHg). Elevated intracranial pressure was seen in 83.1% of patients, as estimated based on ONSD ≥5.8 mm. A mortality rate of 16.2% was reported. In the multivariate analysis, age was associated with elevated ONSD (risk ratio [RR] = 1.07). PaCO2 was a protective factor (RR = 0.64) in the cases of PI ≥ 1.1. In the mortality analysis, the mean velocity was a risk factor for mortality (RR = 1.15).

Conclusions

A high rate of intracranial hypertension was reported, with ONSD measurement being the most reliable method for estimation. The increase in ICP measured by ONSD in patients with severe COVID-19 on mechanical ventilation is not associated to hypercapnia or elevated intrathoracic pressures derived from protective mechanical ventilation.

Prone positioning does not improve outcomes of intubated patients with pneumocystis pneumonia and moderate-severe acute respiratory distress syndrome: a single-center, retrospective, observational, cohort study

BACKGROUND

Pneumocystis pneumonia is an uncommon precipitant of acute respiratory distress syndrome and is associated with high mortality. Prone positioning ventilation has been proven to reduce mortality in patients with moderate-severe acute respiratory distress syndrome. We investigated the effect of prone positioning on oxygenation and mortality in intubated patients with pneumocystis pneumonia comorbid with moderate-severe acute respiratory distress syndrome.

METHODS

In this single-center, retrospective, observational, cohort study, eligible patients were enrolled at West China Hospital of Sichuan University from January 1, 2017, to December 31, 2021. Data on demographics, clinical features, ventilation parameters, arterial blood gas, and outcomes were collected. Patients were assigned to the prone cohort or supine cohort according to whether they received prone positioning ventilation. The main outcome was 28-day mortality.

FINDINGS

A total of 79 patients were included in the study. Sixty-three patients were enrolled in the prone cohort, and 16 patients were enrolled in the supine cohort. The 28-day mortality was 61.9% in the prone cohort and 68.8% in the supine cohort (P = 0.26), and 90-day mortality was 66.7% in the prone cohort and 68.8% in the supine cohort (P = 0.55). Patients in the supine cohort had fewer invasive mechanical ventilation days and more ventilator-free days. The incidence of complications was higher in the prone cohort than in the supine cohort.

CONCLUSIONS

In patients with pneumocystis pneumonia and moderate-severe acute respiratory distress syndrome, prone positioning did not decrease 28-day or 90-day mortality. Trial registration ClinicalTrials.gov number, ChiCTR2200063889. Registered on 20 September 2022, https://www.chictr.org.cn/showproj.html?proj=174886 .

The suppression of HSPA8 attenuates NLRP3 ubiquitination through SKP2 to promote pyroptosis in sepsis-induced lung injury

BACKGROUND

Acute lung injury (ALI) is strongly associated with hospitalization and mortality in patients with sepsis. Recent evidence suggests that pyroptosis mediated by NLRP3(NOD-, LRR- and pyrin domain-containing 3) inflammasome activation plays a key role in sepsis. However, the mechanism of NLRP3 inflammasome activation in sepsis-induced lung injury remains unclear.

RESULTS

in this study, we demonstrated that NLRP3 inflammasome was activated by the down-regulation of heat shock protein family A member 8 (HSPA8) in Lipopolysaccharide (LPS) and adenosine triphosphate (ATP)-treated mouse alveolar epithelial cells (AECs). Geranylgeranylacetone (GGA)-induced HSPA8 overexpression in cecum ligation and puncture (CLP) mice could significantly reduce systemic inflammatory response and mortality, effectively protect lung function, whilst HSPA8 inhibitor VER155008 aggravated this effect. The inhibition of HSPA8 was involved in sepsis induced acute lung injury by promoting pyroptosis of AECs. The down-regulation of HSPA8 activated NLRP3 inflammasome to mediate pyroptosis by promoting the degradation of E3 ubiquitin ligase S-phase kinase-associated protein 2 (SKP2). In addition, when stimulated by LPS and ATP, down-regulated SKP2 promoted pyroptosis of AECs by further attenuating ubiquitination of NLRP3. Adeno-associated virus 9-SKP2(AAV9-SKP2) could promote NLRP3 ubiquitination and degradation, alleviate lung injury and inhibit systemic inflammatory response in vivo.

CONCLUSION

in summary, our study shows there is strong statistical evidence that the suppression of HSPA8 mediates alveolar epithelial pyroptosis by promoting the degradation of E3 ubiquitin ligase SKP2 and subsequently attenuating the ubiquitination of NLRP3 to activate the NLRP3 inflammasome, which provides a new perspective and therapeutic target for the treatment of sepsis-induced lung injury.

Emerging application of nanomedicine-based therapy in acute respiratory distress syndrome

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are serious lung injuries caused by various factors, leading to increased permeability of the alveolar-capillary barrier, reduced stability of the alveoli, inflammatory response, and hypoxemia. Despite several decades of research since ARDS was first formally described in 1967, reliable clinical treatment options are still lacking. Currently, supportive therapy and mechanical ventilation are prioritized, and there is no medication that can be completely effective in clinical treatment. In recent years, nanomedicine has developed rapidly and has exciting preclinical treatment capabilities. Using a drug delivery system based on nanobiotechnology, local drugs can be continuously released in lung tissue at therapeutic levels, reducing the frequency of administration and improving patient compliance. Furthermore, this novel drug delivery system can target specific sites and reduce systemic side effects. Currently, many nanomedicine treatment options for ARDS have demonstrated efficacy. This review briefly introduces the pathophysiology of ARDS, discusses various research progress on using nanomedicine to treat ARDS, and anticipates future developments in related fields.

Pharmacological Activities of Plant-Derived Fraxin with Molecular Mechanisms: A Comprehensive Review

Fruits and vegetables serve not only as sources of nutrition but also as medicinal agents for the treatment of diverse diseases and maladies. These dietary components are significant resources of phytochemicals that demonstrate therapeutic properties against many illnesses. Fraxin is a naturally occurring coumarin glycoside mainly present in various species of Fraxinus genera, having a multitude of therapeutic uses against various diseases and disorders. This study focuses to investigate the pharmacological activities, botanical sources, and biopharmaceutical profile of the phytochemical fraxin based on different preclinical and non-clinical studies to show the scientific evidence and to evaluate the underlying molecular mechanisms of the therapeutic effects against various ailments. For this, data was searched and collected (as of February 15, 2024) in a variety of credible electronic databases, including PubMed/Medline, Scopus, Springer Link, ScienceDirect, Wiley Online, Web of Science, and Google Scholar. The findings demonstrated favorable outcomes in relation to a range of diseases or medical conditions, including inflammation, neurodegenerative disorders such as cerebral ischemia-reperfusion (I/R) and depression, viral infection, as well as diabetic nephropathy. The phytochemical also showed protective effects such as osteoprotective, renoprotective, pulmoprotective, hepatoprotective, and gastroprotective effects due to its antioxidant capacity. Fraxin has a great capability to diminish oxidative stress-related damage in different organs by stimulating the antioxidant enzymes, downregulating nuclear factor kappa B and NLRP3, and triggering the Nrf2/ARE signaling pathways. Fraxin exhibited poor oral bioavailability because of reduced absorption and a wide distribution into tissues of different organs. However, extensive research is required to decipher the biopharmaceutical profiles, and clinical studies are necessary to establish the efficacy of the natural compound as a reliable therapeutic agent.

[COVID-19 in the intensive care unit]

The acute respiratory failure as well as ARDS (acute respiratory distress syndrome) have challenged clinicians since the initial description over 50 years ago. Various causes can lead to ARDS and therapeutic approaches for ARDS/ARF are limited to the support or replacement of organ functions and the prevention of therapy-induced consequences. In recent years, triggered by the SARS-CoV-2 pathogen, numerous cases of acute lung failure (C-ARDS) have emerged. The pathophysiological processes of classical ARDS and C-ARDS are essentially similar. In their final stages of inflammation, both lead to a disruption of the blood-air barrier. Treatment strategies for C-ARDS, like classical ARDS, focus on supporting or replacing organ functions and preventing consequential damage. This article summarizes the treatment strategies in the intensive care unit.

Comparison of lung ultrasound scoring systems for the prognosis of COVID-19 in the emergency department: An international prospective cohort study

Purpose

The purpose of this study was to evaluate whether the lung ultrasound (LUS) scores applied to an international cohort of patients presenting to the emergency department (ED) with suspected COVID-19, and subsequently admitted with proven disease, could prognosticate clinical outcomes.

Methods

This was an international, multicentre, prospective, observational cohort study of patients who received LUS and were followed for the composite primary outcome of intubation, intensive care unit (ICU) admission or death. LUS scores were later applied including two 12-zone protocols ('de Alencar score' and 'CLUE score'), a 12-zone protocol with lung and pleural findings ('Ji score') and an 11-zone protocol ('Tung-Chen score'). The primary analysis comprised logistic regression modelling of the composite primary outcome, with the LUS scores analysed individually as predictor variables.

Results

Between April 2020 to April 2022, 129 patients with COVID-19 had LUS performed according to the protocol and 24 (18.6%) met the composite primary endpoint. No association was seen between the LUS score and the composite primary end point for the de Alencar score [odds ratio (OR) = 1.04; 95% confidence interval (CI): 0.97-1.11; P = 0.29], the CLUE score (OR = 1.03; 95% CI: 0.96-1.10; P = 0.40), the Ji score (OR = 1.02; 95% CI: 0.97-1.07; P = 0.40) or the Tung-Chen score (OR = 1.02; 95% CI: 0.97-1.08).

Discussion

Compared to these earlier studies performed at the start of the pandemic, the negative outcome of our study could reflect the changing scenario of the COVID-19 pandemic, including patient, disease, and system factors. The analysis suggests that the study may have been underpowered to detect a weaker association between a LUS score and the primary outcome.

Conclusion

In an international cohort of adult patients presenting to the ED with suspected COVID-19 disease who had LUS performed and were subsequently admitted to hospital, LUS severity scores did not prognosticate the need for invasive ventilation, ICU admission or death.

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

OBJECTIVE

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

DATA SOURCES

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

STUDY SELECTION AND DATA EXTRACTION

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

DATA SYNTHESIS

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

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

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

CONCLUSIONS

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

Endothelial cell dynamics in sepsis-induced acute lung injury and acute respiratory distress syndrome: pathogenesis and therapeutic implications

Sepsis, a prevalent critical condition in clinics, continues to be the leading cause of death from infections and a global healthcare issue. Among the organs susceptible to the harmful effects of sepsis, the lungs are notably the most frequently affected. Consequently, patients with sepsis are predisposed to developing acute lung injury (ALI), and in severe cases, acute respiratory distress syndrome (ARDS). Nevertheless, the precise mechanisms associated with the onset of ALI/ARDS remain elusive. In recent years, there has been a growing emphasis on the role of endothelial cells (ECs), a cell type integral to lung barrier function, and their interactions with various stromal cells in sepsis-induced ALI/ARDS. In this comprehensive review, we summarize the involvement of endothelial cells and their intricate interplay with immune cells and stromal cells, including pulmonary epithelial cells and fibroblasts, in the pathogenesis of sepsis-induced ALI/ARDS, with particular emphasis placed on discussing the several pivotal pathways implicated in this process. Furthermore, we discuss the potential therapeutic interventions for modulating the functions of endothelial cells, their interactions with immune cells and stromal cells, and relevant pathways associated with ALI/ARDS to present a potential therapeutic strategy for managing sepsis and sepsis-induced ALI/ARDS.

Pseudomonas aeruginosa Infections in Patients with Severe COVID-19 in Intensive Care Units: A Retrospective Study

Patients hospitalized in ICUs with severe COVID-19 are at risk for developing hospital-acquired infections, especially infections caused by Pseudomonas aeruginosa. We aimed to describe the evolution of P. aeruginosa infections in ICUs at CHRU-Nancy (France) in patients with severe COVID-19 during the three initial waves of COVID-19. The second aims were to analyze P. aeruginosa resistance and to describe the antibiotic treatments. We conducted a retrospective cohort study among adult patients who were hospitalized for acute respiratory distress syndrome due to COVID-19 and who developed a hospital-acquired infection caused by P. aeruginosa during their ICU stay. Among the 51 patients included, most were male (90%) with comorbidities (77%), and the first identification of P. aeruginosa infection occurred after a median ICU stay of 11 days. Several patients acquired infections with MDR (27%) and XDR (8%) P. aeruginosa strains. The agents that strains most commonly exhibited resistance to were penicillin + β-lactamase inhibitors (59%), cephalosporins (42%), monobactams (32%), and carbapenems (27%). Probabilistic antibiotic treatment was prescribed for 49 patients (96%) and was subsequently adapted for 51% of patients after antibiogram and for 33% of patients after noncompliant antibiotic plasma concentration. Hospital-acquired infection is a common and life-threatening complication in critically ill patients. Efforts to minimize the occurrence and improve the treatment of such infections, including infections caused by resistant strains, must be pursued.

Integrative Analyses of Bulk and Single-Cell RNA Seq Identified the Shared Genes in Acute Respiratory Distress Syndrome and Rheumatoid Arthritis

Acute respiratory distress syndrome (ARDS), a progressive status of acute lung injury (ALI), is primarily caused by an immune-mediated inflammatory disorder, which can be an acute pulmonary complication of rheumatoid arthritis (RA). As a chronic inflammatory disease regulated by the immune system, RA is closely associated with the occurrence and progression of respiratory diseases. However, it remains elusive whether there are shared genes between the molecular mechanisms underlying RA and ARDS. The objective of this study is to identify potential shared genes for further clinical drug discovery through integrated analysis of bulk RNA sequencing datasets obtained from the Gene Expression Omnibus database, employing differentially expressed genes (DEGs) analysis and weighted gene co-expression network analysis (WGCNA). The hub genes were identified through the intersection of common DEGs and WGCNA-derived genes. The Random Forest (RF) and least absolute shrinkage and selection operator (LASSO) algorithms were subsequently employed to identify key shared target genes associated with two diseases. Additionally, RA immune infiltration analysis and COVID-19 single-cell transcriptome analysis revealed the correlation between these key genes and immune cells. A total of 59 shared genes were identified from the intersection of DEGs and gene clusters obtained through WGCNA, which analyzed the integrated gene matrix of ALI/ARDS and RA. The RF and LASSO algorithms were employed to screen for target genes specific to ALI/ARDS and RA, respectively. The final set of overlapping genes (FCMR, ADAM28, HK3, GRB10, UBE2J1, HPSE, DDX24, BATF, and CST7) all exhibited a strong predictive effect with an area under the curve (AUC) value greater than 0.8. Then, the immune infiltration analysis revealed a strong correlation between UBE2J1 and plasma cells in RA. Furthermore, scRNA-seq analysis demonstrated differential expression of these nine target genes primarily in T cells and NK cells, with CST7 showing a significant positive correlation specifically with NK cells. Beyond that, transcriptome sequencing was conducted on lung tissue collected from ALI mice, confirming the substantial differential expression of FCMR, HK3, UBE2J1, and BATF. This study provides unprecedented evidence linking the pathophysiological mechanisms of ALI/ARDS and RA to immune regulation, which offers novel understanding for future clinical treatment and experimental research.

ARC@DPBNPs suppress LPS-induced acute lung injury via inhibiting macrophage pyroptosis and M1 polarization by ERK pathway in mice

AIM OF THE STUDY

Exploring the protective effect of ARC@DPBNP on lipopolysaccharides (LPS)-induced ALI and its underlying mechanism.

MATERIALS AND METHODS

ALI model was established by intransally administrating LPS (4 mg/kg) into C57BL/6 mice. The suppression effects of ALI was first compared between ARC (intragastric administrated, with doses ranging from 10 to 80 mg/kg) and ARC@BPBNPs (intratracheally administrated, with doses ranging from 1 to 4 mg/kg). Changes in lung histology post intratracheal intervention of 3 mg/kg ARC@DPBNPs were detected. The expression of pyrotosis pathway-related proteins in lungs as well as in RAW264.7 cells was detected by western blotting. The ASC expression in lung macrophages was examined using immune-fluorescent staining. The polarization of RAW264.7 cells and lung macrophages were detected by flow cytometry. The network pharmacology was constructed by Cytoscape, and the molecular docking was perfomed by AutoDock Vina.

RESULTS

Docking predicted the high affinity of ARC to MAPK1 (ERK2). HE staining showed that ARC@DPBNPs attenuated LPS-induced ALI at a remarkably lower dose than ARC. The improved histopathological changes, lung W/D weight ratio, and decreased of inflammatory factor levels in lung collectively demonstrated the alleviation effects of ARC@DPBNPs. Compared with the LPS group, ARC@DPBNPs down-regulated the ERK pathway, resulted in a suppression of the macrophage pyroptosis and M1 polarization. This suppression effects could be removed by the ERK activator Ro 67-7476.

CONCLUSION

ARC@DPBNPs attenuated ALI by suppressing LPS-induced macrophage pyroptosis and polarization, probably through down-regulation of the ERK pathway.

miR-186-5p improves alveolar epithelial barrier function by targeting the wnt5a/β-catenin signaling pathway in sepsis-acute lung injury

BACKGROUND

Alveolar epithelial barrier dysfunction is one of the pathological features of sepsis-acute lung injury(ALI). However, the molecular mechanisms that regulate the function of alveolar epithelial barrier remain unclear. This study aimed to determine the regulatory role of miR-186-5p in alveolar epithelial barrier function in sepsis-ALI and its underlying molecular mechanism.

METHODS

We established sepsis-ALI models in vivo and in vitro, detected the miR-186-5p and wnt5a/β-catenin expressions, and observed the functional changes of the alveolar epithelial barrier by miR-186-5p overexpression. We used rescue experiments to clarify whether miR-186-5p works through wnt5a/β-catenin.

RESULTS

miR-186-5p expression was decreased, wnt5a expression was increased, and the wnt5a/β-catenin signaling pathway was activated in mouse lung tissues and A549 cells after inflammatory stimulation. miR-186-5p overexpression resulted in wnt5a/β-catenin signaling pathway inhibition, decreased apoptosis in A549 cells, improved alveolar epithelial barrier function, reduced lung tissue injury in ALI mice, decreased IL-6 and TNF-α levels, and increased claudin4 and ZO-1 expression. Using miRNA-related database prediction and dual-luciferase reporter gene analysis, the targeting relationship between miR-186-5p and wnt5a was determined. The protective effect produced by miR-186-5p overexpression on the alveolar barrier was reversed after the application of the wnt5a/β-catenin activator Licl.

CONCLUSION

Our experimental data suggest miR-186-5p targets the wnt5a/β-catenin pathway, thereby regulating alveolar epithelial barrier function. Furthermore, both miR-186-5p and wnt5a/β-catenin are potential therapeutic targets that could impact sepsis-ALI.

TSPO deficiency exacerbates acute lung injury via NLRP3 inflammasome-mediated pyroptosis

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a common cause of respiratory failure in many critically disease patients. Although inflammasome activation plays an important role in the induction of acute lung injury (ALI) and ARDS, the regulatory mechanism of this process is still unclear. When cells are stimulated by inflammation, the integrity and physiological function of mitochondria play a crucial part in pyroptosis. However, the underlying mechanisms and function of mitochondrial proteins in the process of pyroptosis are largely not yet known. Here, we identified the 18-kDa translocator protein (TSPO), a mitochondrial outer membrane protein, as an important mediator regulating nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome activation in macrophages during ALI.

METHODS

TSPO gene knockout (KO) and lipopolysaccharide (LPS)-induced ALI/ARDS mouse models were employed to investigate the biological role of TSPO in the pathogenesis of ARDS. Murine macrophages were used to further characterize the effect of TSPO on the NLRP3 inflammasome pathway. Activation of NLRP3 inflammasome through LPS + adenosine triphosphate (ATP) co-stimulation, followed by detection of mitochondrial membrane potential, reactive oxygen species (ROS) production, and cell death was preformed to evaluate the potential biological function of TSPO. Comparisons between two groups were performed with a two-sided unpaired t-test.

RESULTS

TSPO-KO mice exhibited more severe pulmonary inflammation in response to LPS-induced ALI. TSPO deficiency resulted in enhanced activation of the NLRP3 inflammasome pathway, promoting more proinflammatory cytokine production of macrophages in LPS-injured lung tissue, including interleukin (IL)-1β, IL-18, and macrophage inflammatory protein (MIP)-2. Mitochondria in TSPO-KO macrophages tended to depolarize in response to cellular stress. The increased production of mitochondrial damage-associated molecular pattern (mtDAMP) led to enhanced mitochondrial membrane depolarization and pyroptosis in TSPO-KO cells.

CONCLUSION

TSPO may be the key regulatory of cellular pyroptosis, it plays a vital protective role in ARDS occurrence and development.

[Risk factors for acute respiratory distress syndrome in patients with traumatic hemorrhagic shock]

OBJECTIVE

To investigate the risk factors of acute respiratory distress syndrome (ARDS) after traumatic hemorrhagic shock.

METHODS

This was a retrospective cohort study of 314 patients with traumatic hemorrhagic shock at Trauma Medicine Center, Peking University People's Hospital from December 2012 to August 2021, including 152 male patients and 162 female patients, with a median age of 63.00 (49.75-82.00) years. The demographic data, past medical history, injury assessment, vital signs, laboratory examination and other indicators of these patients during hospitalization were recorded. These patients were divided into two groups, ARDS group (n=89) and non-ARDS group (n=225) according to whether there was ARDS within 7 d of admission. Risk factors for ARDS were identified using Logistic regression. The C-statistic expressed as a percentage [area under curve (AUC) of the receiver operating characteristic (ROC) curve] was used to assess the discrimination of the model.

RESULTS

The incidence of ARDS after traumatic hemorrhagic shock was 28.34%. Finally, Logistic regression model showed that the independent risk factors of ARDS after traumatic hemorrhagic shock included male, history of coronary heart disease, high acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score, road traffic accident and elevated troponin Ⅰ. The OR and 95% confidence intervals (CI) were 4.01 (95%CI: 1.75-9.20), 5.22 (95%CI: 1.29-21.08), 1.07 (95%CI: 1.02-1.57), 2.53 (95%CI: 1.21-5.28), and 1.26 (95%CI: 1.02-1.57), respectively; the P values were 0.001, 0.020, 0.009, 0.014, and 0.034, respectively. The ROC curve was used to analyze the value of each risk factor in predicting ARDS. It was found that the AUC for predicting ARDS after traumatic hemorrhagic shock was 0.59 (95%CI: 0.51-0.68) for male, 0.55 (95%CI: 0.46-0.64) for history of coronary heart disease, 0.65 (95%CI: 0.57-0.73) for APACHE Ⅱ score, 0.58 (95%CI: 0.50-0.67) for road traffic accident, and 0.73 (95%CI: 0.66-0.80) for elevated troponin Ⅰ, with an overall predictive value of 0.81 (95%CI: 0.74-0.88).

CONCLUSION

The incidence of ARDS in patients with traumatic hemorrhagic shock is high, and male, history of coronary heart disease, high APACHE Ⅱ score, road traffic accident and elevated troponin Ⅰ are independent risk factors for ARDS after traumatic hemorrhagic shock. Timely monitoring these indicators is conducive to early detection and treatment of ARDS after traumatic hemorrhagic shock.

Modulation of alveolar macrophage and mitochondrial fitness by medicinal plant-derived nanovesicles to mitigate acute lung injury and viral pneumonia

Acute lung injury (ALI) is generally caused by severe respiratory infection and characterized by overexuberant inflammatory responses and inefficient pathogens-containing, the two major processes wherein alveolar macrophages (AMs) play a central role. Dysfunctional mitochondria have been linked with distorted macrophages and hence lung disorders, but few treatments are currently available to correct these defects. Plant-derive nanovesicles have gained significant attention because of their therapeutic potential, but the targeting cells and the underlying mechanism remain elusive. We herein prepared the nanovesicles from Artemisia annua, a well-known medicinal plant with multiple attributes involving anti-inflammatory, anti-infection, and metabolism-regulating properties. By applying three mice models of acute lung injury caused by bacterial endotoxin, influenza A virus (IAV) and SARS-CoV-2 pseudovirus respectively, we showed that Artemisia-derived nanovesicles (ADNVs) substantially alleviated lung immunopathology and raised the survival rate of challenged mice. Macrophage depletion and adoptive transfer studies confirmed the requirement of AMs for ADNVs effects. We identified that gamma-aminobutyric acid (GABA) enclosed in the vesicles is a major molecular effector mediating the regulatory roles of ADNVs. Specifically, GABA acts on macrophages through GABA receptors, promoting mitochondrial gene programming and bioenergy generation, reducing oxidative stress and inflammatory signals, thereby enhancing the adaptability of AMs to inflammation resolution. Collectively, this study identifies a promising nanotherapeutics for alleviating lung pathology, and elucidates a mechanism whereby the canonical neurotransmitter modifies AMs and mitochondria to resume tissue homeostasis, which may have broader implications for treating critical pulmonary diseases such as COVID-19.

Smoking on the risk of acute respiratory distress syndrome: a systematic review and meta-analysis

BACKGROUND

The relationship between smoking and the risk of acute respiratory distress syndrome (ARDS) has been recognized, but the conclusions have been inconsistent. This systematic review and meta-analysis investigated the association between smoking and ARDS risk in adults.

METHODS

The PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched for eligible studies published from January 1, 2000, to December 31, 2023. We enrolled adult patients exhibiting clinical risk factors for ARDS and smoking condition. Outcomes were quantified using odds ratios (ORs) for binary variables and mean differences (MDs) for continuous variables, with a standard 95% confidence interval (CI).

RESULTS

A total of 26 observational studies involving 36,995 patients were included. The meta-analysis revealed a significant association between smoking and an increased risk of ARDS (OR 1.67; 95% CI 1.33-2.08; P < 0.001). Further analysis revealed that the associations between patient-reported smoking history and ARDS occurrence were generally similar to the results of all the studies (OR 1.78; 95% CI 1.38-2.28; P < 0.001). In contrast, patients identified through the detection of tobacco metabolites (cotinine, a metabolite of nicotine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a metabolite of tobacco products) showed no significant difference in ARDS risk (OR 1.19; 95% CI 0.69-2.05; P = 0.53). The smoking group was younger than the control group (MD - 7.15; 95% CI - 11.58 to - 2.72; P = 0.002). Subgroup analysis revealed that smoking notably elevated the incidence of ARDS with extrapulmonary etiologies (OR 1.85; 95% CI 1.43-2.38; P < 0.001). Publication bias did not affect the integrity of our conclusions. Sensitivity analysis further reinforced the reliability of our aggregated outcomes.

CONCLUSIONS

There is a strong association between smoking and elevated ARDS risk. This emphasizes the need for thorough assessment of patients' smoking status, urging healthcare providers to vigilantly monitor individuals with a history of smoking, especially those with additional extrapulmonary risk factors for ARDS.

Bovine lactoferrin inhibits inflammatory response and apoptosis in lipopolysaccharide-induced acute lung injury by targeting the PPAR-γ pathway

BACKGROUND

Lactoferrin (LF) is an iron-binding multifunctional cationic glycoprotein. Previous studies have demonstrated that LF may be a potential drug for treating acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In this study, we explored the anti-inflammatory effect and mechanism of bovine lactoferrin (bLF) in ALI using the RNA sequencing (RNA-seq) technology and transcriptome analysis.

METHODS AND RESULTS

Based on the differentially expressed genes (DEGs) obtained from RNA-seq of the Lung from mouse model, the bioinformatics workflow was implemented using the BGISEQ-500 platform. The protein-protein interaction (PPI) network was obtained using STRING, and the hub gene was screened using Cytoscape. To verify the results of transcriptome analysis, the effects of bLF on Lipopolysaccharide (LPS)-induced BEAS-2B cells and its anti-reactive oxygen species (ROS), anti-inflammatory, and antiapoptotic effects were studied via Cell Counting Kit-8 (CCK-8) test, active oxygen detection test, ELISA, and western blot assay. Transcriptome analysis revealed that two hub gene modules of DEGs were screened via PPI analysis using the STRING and MCODE plug-ins of Cytoscape. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that these core modules are enriched in the PPAR (peroxisome proliferator-activated receptor) and AMPK (AMP-activated protein kinase) signaling pathways. Through cell experiments, our study shows that bLF can inhibit ROS, inflammatory reaction, and LPS-induced BEAS-2B cell apoptosis, which are significantly antagonized by the PPAR-γ inhibitor GW9662.

CONCLUSION

This study has suggested that the PPAR-γ pathway is the critical target of bLF in anti-inflammatory reactions and apoptosis of ALI, which provides a direction for further research.

Lung microbiota composition, respiratory mechanics, and outcomes in COVID-19-related ARDS

Few data are available on the lung microbiota composition of patients with coronavirus disease 2019-related acute respiratory distress syndrome (C-ARDS) receiving invasive mechanical ventilation (IMV). Moreover, it has never been investigated whether there is a potential correlation between lung microbiota communities and respiratory mechanics. We performed a prospective observational study in two intensive care units of a university hospital in Italy. Lung microbiota was investigated by bacterial 16S rRNA gene sequencing, performed on bronchoalveolar lavage fluid samples withdrawn after intubation. The lung bacterial communities were analyzed after stratification by respiratory system compliance/predicted body weight (Crs) and ventilatory ratio (VR). Weaning from IMV and hospital survival were assessed as secondary outcomes. In 70 C-ARDS patients requiring IMV from 1 April through 31 December 2020, the lung microbiota composition (phylum taxonomic level, permutational multivariate analysis of variance test) significantly differed between who had low Crs vs those with high Crs (P = 0.010), as well as in patients with low VR vs high VR (P = 0.012). As difference-driving taxa, Proteobacteria (P = 0.017) were more dominant and Firmicutes (P = 0.040) were less dominant in low- vs high-Crs patients. Similarly, Proteobacteria were more dominant in low- vs high-VR patients (P = 0.013). After multivariable regression analysis, we further observed lung microbiota diversity as a negative predictor of weaning from IMV and hospital survival (hazard ratio = 3.31; 95% confidence interval, 1.52-7.20, P = 0.048). C-ARDS patients with low Crs/low VR had a Proteobacteria-dominated lung microbiota. Whether patients with a more diverse lung bacterial community may have more chances to be weaned from IMV and discharged alive from the hospital warrants further large-scale investigations.

IMPORTANCE

Lung microbiota characteristics were demonstrated to predict ventilator-free days and weaning from mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). In this study, we observed that in severe coronavirus disease 2019 patients with ARDS who require invasive mechanical ventilation, lung microbiota characteristics were associated with respiratory mechanics. Specifically, the lung microbiota of patients with low respiratory system compliance and low ventilatory ratio was characterized by Proteobacteria dominance. Moreover, after multivariable regression analysis, we also found an association between patients' microbiota diversity and a higher possibility of being weaned from mechanical ventilation and discharged alive from the hospital. For these reasons, lung microbiota characterization may help to stratify patient characteristics and orient the delivery of target interventions. (This study has been registered at ClinicalTrials.gov on 17 February 2020 under identifier NCT04271345.).

Registered at ClinicalTrials.gov, 17 February 2020 (NCT0427135).

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.

Alpinetin alleviates LPS-induced lung epithelial cell injury by inhibiting p38 and ERK1/2 signaling via aquaporin-1

Alpinetin has been reported to play a protective role in lung diseases, while its special mechanisms remain indistinct. In this study, acute lung injury (ALI) model was constructed by inducing MLE-12 cells with lipopolysaccharide (LPS). Cell activity together with apoptosis was judged employing cell counting kit-8 (CCK-8), flow cytometry along with western blot. Oxidative stress levels were measured by dichloro-dihydro-fluorescein diacetate (DCFH-DA) staining and corresponding kits. In addition, enzyme-linked immunosorbent assay (ELISA) was to examine the levels of inflammatory factors. The protein expressions of aquaporin-1 (AQP1), p38 and extracellular signal-regulated kinase (ERK) 1/2 pathway were estimated utilizing western blot. The data showed that alpinetin increased the viability, reduced the apoptosis, oxidative stress and inflammation and inactivated p38 and ERK1/2 signaling in LPS-induced MLE-12 cells. Moreover, alpinetin also increased AQP1 expression and AQP1 knockdown reversed the impacts of alpinetin on LPS-induced MLE-12 cells. Additionally, AQP1 agonist AqF026 also exerted anti-apoptotic and anti-inflammatory activities in LPS-treated MLE-12 cells. Evidently, alpinetin may exert its protective role in LPS-induced ALI by inactivation of p38 and ERK1/2 signaling through regulating AQP1.