Predictive value of plasma sICAM-1 and sP-Selectins in the risk of death in patients with acute respiratory distress syndrome

Background

To evaluate the predictive value of sICAM-1 and sP-Selectins in the risk of death in a prospective cohort of adult acute respiratory distress syndrome (ARDS).

Methods

Adult ARDS patients were included. Plasma sICAM-1, sP-Selectins, and inflammatory cytokines (TNF-α, IL-1b, IL-6, IL-8, and IL-17A) were detected in ARDS subjects. The correlation between different factors and the potential of sICAM-1 and sP-Selectins as endothelial markers to predict the risk of deathfrom ARDS was analyzed.

Predictive value of combination of lung injury prediction score and receptor for advanced glycation end‑products for the occurrence of acute respiratory distress syndrome

The present study evaluated the predictive value of the combination of the lung injury prediction score (LIPS) and receptor for advanced glycation end-products (RAGE) for the occurrence of acute respiratory distress syndrome (ARDS) in critically ill patients with ARDS risk factors. A total of 551 patients with risk factors of ARDS were divided into an ARDS group and a non-ARDS group. LIPS was computed within 6 h of admission into the ICU, and the plasma concentration of RAGE was detected within 24 h of admission. Multivariate analysis was performed to identify independent associations, and the predictive values for ARDS occurrence were assessed with receiver operating characteristic (ROC) curve. Within 7 days after admission into the ICU, ARDS occurred in 176 patients (31.9%). Multivariate analysis demonstrated that LIPS [odds ratio (OR), 1.282; 95% confidence interval (CI), 1.108-1.604], RAGE levels (OR, 2.359; 95% CI, 1.351-4.813) and Acute Physiology and Chronic Health Evaluation II score (OR, 1.167; 95% CI, 1.074-1.485) were independently associated with ARDS occurrence. ROC curves demonstrated that the area under curve (AUC) of LIPS, RAGE levels and their combination was 0.714 [standard error (SE), 0.023; 95% CI, 0.670-0.759], 0.709 (SE, 0.025; 95% CI, 0.660-0.758) and 0.889 (SE, 0.014; 95% CI, 0.861-0.917), respectively. The AUC of LIPS combined with RAGE levels was significantly higher compared with those of LIPS (0.889 vs. 0.714; Z=6.499; P<0.001) and RAGE (0.889 vs. 0.709; Z=6.282; P<0.001) levels alone. In conclusion, both LIPS and RAGE levels were independently associated with ARDS occurrence in critically ill patients with ARDS risk factors, and had medium predictive values for ARDS occurrence. Combination of LIPS with RAGE levels increased the predictive value for ARDS occurrence.

Pillar arene Se nanozyme therapeutic systems with dual drive power effectively penetrated mucus layer combined therapy acute lung injury

siRNA has demonstrated a promising paradigm for therapy of acute lung injury(ALI). However, the pulmonary mucus layer barrier powerfully hinders the therapeutic efficacy. Herein, we proposed to use dual drive power to enhance the mucus permeation of siRNA by constructing the neutral and targeted selenium nanozymes therapeutic system. The multifunctional selenium nanozymes (CWP-Se@Man) were synthesized by modifying with cationic water-soluble pillar arene (CWP) and mannose (Man). After loading CCR2-siRNA, the CWP-Se@Man reached electroneutrality that co-driven by electroneutrality and targeting, the mucus permeation capacity of CWP-Se@Man enhanced by ∼15 fold, thus effectively penetrate pulmonary mucus layer and deliver CCR2-siRNA into macrophages. Moreover, with optimizing the composition of CWP-Se@Man made of CWP (Slutsky, 2013) [5] or CWP (Ichikado et al., 2012) [6], the therapeutic system CWP (Ichikado et al., 2012) [6]-Se@Man showed better biological activities due to smaller size. In inflamed modes, the CWP-Se@Man nanotherapeutic systems loading CCR2-siRNA not only exerted pronounced anti-inflammatory effect through combining inhibit the chemotactic effect and ROS, but also effectively against ALI after blocking the circulatory effect of ROS and inflammatory cytokines. Therefore, this strategy of dual-driving force penetration mucus renders a unique approach for mediating trans-mucus nucleic acid delivery in lungs, and provide a promising treatment for the acute lung injury therapy.

Tangeretin attenuates acute lung injury in septic mice by inhibiting ROS-mediated NLRP3 inflammasome activation via regulating PLK1/AMPK/DRP1 signaling axis

OBJECTIVE

NLRP3 inflammasome-mediated pyroptosis of macrophage acts essential roles in the progression of sepsis-induced acute lung injury (ALI). Tangeretin (TAN), enriched in citrus fruit peel, presents anti-oxidative and anti-inflammatory effects. Here, we aimed to explore the potentially protective effect of TAN on sepsis-induced ALI, and the underlying mechanism of TAN in regulating NLRP3 inflammasome.

MATERIAL AND METHODS

The effect of TAN on sepsis-induced ALI and NLRP3 inflammasome-mediated pyroptosis of macrophage were examined in vivo and in vitro using a LPS-treated mice model and LPS-induced murine macrophages, respectively. The mechanism of TAN regulating the activation of NLRP3 inflammasome in sepsis-induced ALI was investigated with HE staining, Masson staining, immunofluorescent staining, ELISA, molecular docking, transmission electron microscope detection, qRT-PCR, and western blot.

RESULTS

TAN could evidently attenuate sepsis-induced ALI in mice, evidenced by reducing pulmonary edema, pulmonary congestion and lung interstitial fibrosis, and inhibiting macrophage infiltration in the lung tissue. Besides, TAN significantly suppressed inflammatory cytokine IL-1β and IL-18 expression in the serum or bronchoalveolar lavage fluid (BALF) samples of mice with LPS-induced ALI, and inhibited NLRP3 inflammasome-mediated pyroptosis of macrophages. Furthermore, we found TAN inhibited ROS production, preserved mitochondrial morphology, and alleviated excessive mitochondrial fission in LPS-induced ALI in mice. Through bioinformatic analysis and molecular docking, Polo-like kinase 1 (PLK1) was identified as a potential target of TAN for treating sepsis-induced ALI. Moreover, TAN significantly inhibited the reduction of PLK1 expression, AMP-activated protein kinase (AMPK) phosphorylation, and Dynamin related protein 1 (Drp1) phosphorylation (S637) in LPS-induced ALI in mice. In addition, Volasertib, a specific inhibitor of PLK1, abolished the protective effects of TAN against NLRP3 inflammasome-mediated pyroptosis of macrophage and lung injury in the cell and mice septic models.

CONCLUSION

TAN attenuates sepsis-induced ALI by inhibiting ROS-mediated NLRP3 inflammasome activation via regulating PLK1/AMPK/DRP1 signaling axis, and TAN is a potentially therapeutic candidate against ALI through inhibiting pyroptosis.

Elastic power, a novel predictor of the severity and prognosis of ARDS

PURPOSE

To explore the predictive value of the new comprehensive respiratory mechanics parameters elastic power (EP) and elastic power normalized to the compliance (Cst-EP) in the evaluation of the severity and 28-day prognosis of ARDS patients.

METHODS

The MIMIC-III database was used to identify ARDS patients under invasive mechanical ventilation for at least 48 h. Their baseline data and ventilatory variables were collected. EP, elastic energy, driving pressure and mechanical power were calculated according to the corresponding formulas. Their value in assessing the severity of ARDS was evaluated. The correlation between Cst-EP and 28-day prognosis of ARDS patients was analyzed.

RESULTS

EP was independently associated with the severity of the ARDS and the odds ratio (OR) was 1.301 [95% CI (1.190-1.423), p < 0.001]. It has higher accuracy for the severity of ARDS, with an optimal cut-off value of 14.6 J/min. The Cst-EP was significantly associated with increased risk of death and the hazard ratio (HR) per 100 J/min × cmH2O/ml × 10-3 was 1.169 [95% CI (1.093-1.250), p < 0.001]. In addition, the 28-day cumulative survival rate of the high Cst-EP group was significantly lower than that of the low Cst-EP group.

CONCLUSION

EP can be used to predict the severity of ARDS, and Cst-EP is associated with mortality during controlled mechanical ventilation in ARDS.

Management of Portal Hypertension in Patients with Acute-on-Chronic Liver Disease

Portal hypertension is central to the pathogenesis of complications of cirrhosis, including acute-on-chronic liver failure (ACLF). Both nonselective beta-blockers and preemptive transjugular portal-systemic stent shunt can lower portal pressure, reducing the risk of variceal bleeding, a known trigger for ACLF. However, in patients with advanced cirrhosis, both could potentially induce ACLF by causing hemodynamic instability and hepatic ischemia, respectively, and therefore must be used with caution. Lowering portal pressure with vasoconstrictor such as terlipressin can reverse the kidney failure but careful patient selection is key for success, with careful monitoring for complications.

Circulatory HMGB1 is an early predictive and prognostic biomarker of ARDS and mortality in a swine model of polytrauma

Acute respiratory distress syndrome (ARDS) is a leading cause of morbidity and mortality in polytrauma patients. Pharmacological treatments of ARDS are lacking, and ARDS patients rely on supportive care. Accurate diagnosis of ARDS is vital for early intervention and improved outcomes but is presently delayed up to days. The use of biomarkers for early identification of ARDS development is a potential solution. Inflammatory mediators high-mobility group box 1 (HMGB1), syndecan-1 (SDC-1), and C3a have been previously proposed as potential biomarkers. For this study, we analyzed these biomarkers in animals undergoing smoke inhalation and 40% total body surface area burns, followed by intensive care for 72 h post-injury (PI) to determine their association with ARDS and mortality. We found that the levels of inflammatory mediators in serum were affected, as well as the degree of HMGB1 and Toll-like receptor 4 (TLR4) signal activation in the lung. The results showed significantly increased HMGB1 expression levels in animals that developed ARDS compared with those that did not. Receiver operating characteristic (ROC) analysis showed that HMGB1 levels at 6 h PI were significantly associated with ARDS development (AUROC=0.77) and mortality (AUROC=0.82). Logistic regression analysis revealed that levels of HMGB1 ≥24.10 ng/ml are associated with a 13-fold higher incidence of ARDS [OR:13.57 (2.76-104.3)], whereas the levels of HMGB1 ≥31.39 ng/ml are associated with a 12-fold increase in mortality [OR: 12.00 (2.36-93.47)]. In addition, we found that mesenchymal stem cell (MSC) therapeutic treatment led to a significant decrease in systemic HMGB1 elevation but failed to block SDC-1 and C3a increases. Immunohistochemistry analyses showed that smoke inhalation and burn injury induced the expression of HMGB1 and TLR4 and stimulated co-localization of HMGB1 and TLR4 in the lung. Interestingly, MSC treatment reduced the presence of HMGB1, TLR4, and the HMGB1-TLR4 co-localization. These results show that serum HMGB1 is a prognostic biomarker for predicting the incidence of ARDS and mortality in swine with smoke inhalation and burn injury. Therapeutically blocking HMGB1 signal activation might be an effective approach for attenuating ARDS development in combat casualties or civilian patients.

miR-223: a key regulator of pulmonary inflammation

Small noncoding RNAs, known as microRNAs (miRNAs), are vital for the regulation of diverse biological processes. miR-223, an evolutionarily conserved anti-inflammatory miRNA expressed in cells of the myeloid lineage, has been implicated in the regulation of monocyte-macrophage differentiation, proinflammatory responses, and the recruitment of neutrophils. The biological functions of this gene are regulated by its expression levels in cells or tissues. In this review, we first outline the regulatory role of miR-223 in granulocytes, macrophages, endothelial cells, epithelial cells and dendritic cells (DCs). Then, we summarize the possible role of miR-223 in chronic obstructive pulmonary disease (COPD), acute lung injury (ALI), coronavirus disease 2019 (COVID-19) and other pulmonary inflammatory diseases to better understand the molecular regulatory networks in pulmonary inflammatory diseases.

Engineered Extracellular Vesicles Derived from Dermal Fibroblasts Attenuate Inflammation in a Murine Model of Acute Lung Injury

Acute respiratory distress syndrome (ARDS) represents a significant burden to the healthcare system, with ≈200 000 cases diagnosed annually in the USA. ARDS patients suffer from severe refractory hypoxemia, alveolar-capillary barrier dysfunction, impaired surfactant function, and abnormal upregulation of inflammatory pathways that lead to intensive care unit admission, prolonged hospitalization, and increased disability-adjusted life years. Currently, there is no cure or FDA-approved therapy for ARDS. This work describes the implementation of engineered extracellular vesicle (eEV)-based nanocarriers for targeted nonviral delivery of anti-inflammatory payloads to the inflamed/injured lung. The results show the ability of surfactant protein A (SPA)-functionalized IL-4- and IL-10-loaded eEVs to promote intrapulmonary retention and reduce inflammation, both in vitro and in vivo. Significant attenuation is observed in tissue damage, proinflammatory cytokine secretion, macrophage activation, influx of protein-rich fluid, and neutrophil infiltration into the alveolar space as early as 6 h post-eEVs treatment. Additionally, metabolomics analyses show that eEV treatment causes significant changes in the metabolic profile of inflamed lungs, driving the secretion of key anti-inflammatory metabolites. Altogether, these results establish the potential of eEVs derived from dermal fibroblasts to reduce inflammation, tissue damage, and the prevalence/progression of injury during ARDS via nonviral delivery of anti-inflammatory genes/transcripts.

Identification of macrophage-related genes in sepsis-induced ARDS using bioinformatics and machine learning

Sepsis-induced acute respiratory distress syndrome (ARDS) is one of the leading causes of death in critically ill patients, and macrophages play very important roles in the pathogenesis and treatment of sepsis-induced ARDS. The aim of this study was to screen macrophage-related biomarkers for the diagnosis and treatment of sepsis-induced ARDS by bioinformatics and machine learning algorithms. A dataset including gene expression profiles of sepsis-induced ARDS patients and healthy controls was downloaded from the gene expression omnibus database. The limma package was used to screen 325 differentially expressed genes, and enrichment analysis suggested enrichment mainly in immune-related pathways and reactive oxygen metabolism pathways. The level of immune cell infiltration was analysed using the ssGSEA method, and then 506 macrophage-related genes were screened using WGCNA; 48 showed differential expression. PPI analysis was also performed. SVM-RFE and random forest map analysis were used to screen 10 genes. Three key genes, SGK1, DYSF and MSRB1, were obtained after validation with external datasets. ROC curves suggested that all three genes had good diagnostic efficacy. The nomogram model consisting of the three genes also had good diagnostic efficacy. This study provides new targets for the early diagnosis of sepsis-induced ARDS.

Network pharmacology, a promising approach to reveal the pharmacology mechanism of Chinese medicine formula

ETHNOPHARMACOLOGICAL RELEVANCE

Network pharmacology is a new discipline based on systems biology theory, biological system network analysis, and multi-target drug molecule design specific signal node selection. The mechanism of action of TCM formula has the characteristics of multiple targets and levels. The mechanism is similar to the integrity, systematization and comprehensiveness of network pharmacology, so network pharmacology is suitable for the study of the pharmacological mechanism of Chinese medicine compounds.

AIM OF THE STUDY

The paper summarizes the present application status and existing problems of network pharmacology in the field of Chinese medicine formula, and formulates the research ideas, up-to-date key technology and application method and strategy of network pharmacology. Its purpose is to provide guidance and reference for using network pharmacology to reveal the modern scientific connotation of Chinese medicine.

MATERIALS AND METHODS

Literatures in this review were searched in PubMed, China National Knowledge Infrastructure (CNKI), Web of Science, ScienceDirect and Google Scholar using the keywords "traditional Chinese medicine", "Chinese herb medicine" and "network pharmacology". The literature cited in this review dates from 2002 to 2022.

RESULTS

Using network pharmacology methods to predict the basis and mechanism of pharmacodynamic substances of traditional Chinese medicines has become a trend.

CONCLUSION

Network pharmacology is a promising approach to reveal the pharmacology mechanism of Chinese medicine formula.

Trends in research on acute lung injury/acute respiratory distress syndrome associated with viral pneumonia from 1992 to 2022: a 31-year bibliometric analysis

Purpose

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a dangerous symptom in patients with severe viral pneumonia. This study aims to comprehensively review the cooperation and influence of countries, institutions, authors and co-cited journals/authors/references and keywords in the field of ALI/ARDS associated with viral pneumonia from the perspective of bibliometrics, evaluate the clustering evolution of knowledge structure, and find hot trends and emerging topics.

Methods

Publications on ALI/ARDS associated with viral pneumonia published from January 1, 1992 to December 31, 2022 were extracted from the Web of Science core collection. The document type was limited to original article or review, with the language set to English. Citespace was used to conduct the bibliometric analysis.

Results

A total of 929 articles were included, and the number of them generally increased over time. The countries with the most published articles in this field are the United States (320 papers) and Fudan University is the institution (15 papers) with the most research results. The New England Journal of Medicine was the most frequently co-cited journal, while the most influential co-cited journal was American Journal of Clinical Pathology. Reinout A Bem and Cao Bin were the most prolific author, but there was no leader in this field. The keywords with both high frequency and high centrality were "pneumonia" (Freq = 169, Central = 0.15), "infection" (Freq = 133, Central = 0.15), "acute lung injury" (Freq = 112, Central = 0.18), "respiratory distress syndrome" (Freq = 108, Central = 0.24), and "disease" (Freq = 61, Central = 0.17). "Failure" was the first keyword with citation bursts. Meanwhile, "coronavirus," "cytokine storm" and "respiratory syndrome coronavirus" continue to burst.

Conclusion

Although there was a surge in literature since 2020, attentions to ALI/ARDS associated with viral pneumonia were still insufficient over last three decades. The communication and cooperation among countries, institutions and authors need to be further strengthened.

Mechanisms of pulmonary microvascular endothelial cells barrier dysfunction induced by LPS: The roles of ceramides and the Txnip/NLRP3 inflammasome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are characterized by pulmonary microvascular endothelial cells (PMVECs) barrier dysfunction and proinflammatory cytokine influx into lung tissue, resulting in pulmonary oedema. Ceramide overproduction is an important mediator of pulmonary hyperinflammation and pulmonary oedema in Acute lung injury (ALI). Ceramides induce NLRP3 inflammasome activation are essential for the hyperinflammatory response. However, the roles and specific mechanisms of ceramide-induced NLRP3 inflammasome activation, proinflammatory cytokine manufacturing and PMVECs barrier dysfunction in ALI are unclear. Herein, pretreatment with the acid sphingomyelinase (ASMase) inhibitor imipramine (but not a neutral sphingomyelinase (NSMase) inhibitor or de novo pathway inhibitor) significantly inhibited ceramide early production in rats with lipopolysaccharide (LPS)-induced ALI; Furthermore, the Txnip/NLRP3 inflammasome activation, proinflammatory cytokine release, increased PMVECs permeability and lung injury were significantly decreased. Verapamil, a Txnip inhibitor, substantially inhibited Txnip/NLRP3 inflammasome activation, proinflammatory cytokine release, increased PMVECs permeability and lung injury in rats with C8-ceramide-induced ALI. In vitro, short hairpin RNA-mediated Txnip silencing significantly inhibited C8-ceramide-induced Txnip/NLRP3 inflammasome activation in NR8383 alveolar macrophages (AMs) and early secretion of the proinflammatory cytokines IL-1β (4-12 h) as well as IL-6 and TNF-α at subsequent times (later than 12 h). However, C8-ceramide significantly increased the early secretion (within 8 h) of the proinflammatory cytokines IL-1β, IL-6 and TNF-α in a co-culture model of NR8383 AMs and PMVECs, and Txnip silencing of NR8383 AMs inhibited the secretion of pro-inflammatory cytokines and reduced cytoskeletal rearrangements, intercellular connection breakage and hyperpermeability in PMVECs. Overall, our results suggest that in LPS-induced ALI, ceramide-mediated Txnip/NLRP3 inflammasome activation in NR8383 AMs leads to early IL-1β release, subsequently inducing PMVECs injury and release of the proinflammatory cytokines IL-6 and TNF-α, ultimately leading to PMVECs barrier dysfunction and ALI.

Current status and prospects of basic research and clinical application of mesenchymal stem cells in acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a common and clinically devastating disease that causes respiratory failure. Morbidity and mortality of patients in intensive care units are stubbornly high, and various complications severely affect the quality of life of survivors. The pathophysiology of ARDS includes increased alveolar-capillary membrane permeability, an influx of protein-rich pulmonary edema fluid, and surfactant dysfunction leading to severe hypoxemia. At present, the main treatment for ARDS is mechanical treatment combined with diuretics to reduce pulmonary edema, which primarily improves symptoms, but the prognosis of patients with ARDS is still very poor. Mesenchymal stem cells (MSCs) are stromal cells that possess the capacity to self-renew and also exhibit multilineage differentiation. MSCs can be isolated from a variety of tissues, such as the umbilical cord, endometrial polyps, menstrual blood, bone marrow, and adipose tissues. Studies have confirmed the critical healing and immunomodulatory properties of MSCs in the treatment of a variety of diseases. Recently, the potential of stem cells in treating ARDS has been explored via basic research and clinical trials. The efficacy of MSCs has been shown in a variety of in vivo models of ARDS, reducing bacterial pneumonia and ischemia-reperfusion injury while promoting the repair of ventilator-induced lung injury. This article reviews the current basic research findings and clinical applications of MSCs in the treatment of ARDS in order to emphasize the clinical prospects of MSCs.

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

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

Extracellular vesicles derived from CD4+ T cells carry DGKK to promote sepsis-induced lung injury by regulating oxidative stress and inflammation

BACKGROUND

Sepsis is an abnormal immune response after infection, wherein the lung is the most susceptible organ to fail, leading to acute lung injury. To overcome the limitations of current therapeutic strategies and develop more specific treatment, the inflammatory process, in which T cell-derived extracellular vesicles (EVs) play a central role, should be explored deeply.

METHODS

Liquid chromatography-tandem mass spectrometry was performed for serum EV protein profiling. The serum diacylglycerol kinase kappa (DGKK) and endotoxin contents of patients with sepsis-induced lung injury were measured. Apoptosis, oxidative stress, and inflammation in A549 cells, bronchoalveolar lavage fluid, and lung tissues of mice were measured by flow cytometry, biochemical analysis, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, and western blot.

RESULTS

DGKK, the key regulator of the diacylglycerol (DAG)/protein kinase C (PKC) pathway, exhibited elevated expression in serum EVs of patients with sepsis-induced lung injury and showed strong correlation with sepsis severity and disease progression. DGKK was expressed in CD4⁺ T cells under regulation of the NF-κB pathway and delivered by EVs to target cells, including alveolar epithelial cells. EVs produced by CD4⁺ T lymphocytes exerted toxic effects on A549 cells to induce apoptotic cell death, oxidative cell damage, and inflammation. In mice with sepsis induced by cecal ligation and puncture, EVs derived from CD4⁺ T cells also promoted tissue damage, oxidative stress, and inflammation in the lungs. These toxic effects of T cell-derived EVs were attenuated by the inhibition of PKC and NOX4, the downstream effectors of DGKK and DAG.

CONCLUSIONS

This approach established the mechanism that T-cell-derived EVs carrying DGKK triggered alveolar epithelial cell apoptosis, oxidative stress, inflammation, and tissue damage in sepsis-induced lung injury through the DAG/PKC/NOX4 pathway. Thus, T-cell-derived EVs and the elevated distribution of DGKK should be further investigated to develop therapeutic strategies for sepsis-induced lung injury.

Effect of respiratory training on respiratory failure secondary to unilateral phrenic nerve injury: A case report

INTRODUCTION

Diaphragm is one of the most important respiratory muscles dominated by the phrenic nerve. Phrenic nerve injury would induce a series of clinical symptoms, including respiratory failure. Respiratory training could assist in regular treatment in improving the respiratory function and daily ability of respiratory failure patients.

CASE PRESENTATION

A 71-years-old female was enrolled for the disorders of consciousness of 4.5 hours observed by her family and was diagnosed with respiratory failure secondary to unilateral phrenic nerve injury. The patient received basic therapy combined with rehabilitation training, including the training of aspirate muscle, limb resistance, thoracic loosening, aerobic training, electrical stimulation on respiratory nerves, and airway clearance. The combining therapeutic strategy significantly improved the daily ability and respiratory of the patient. The ultrasound showed that after therapy, the diaphragmatic muscles were thickened and the range of diaphragmatic movement was also enhanced. The pulmonary function was also improved after therapy.

CONCLUSION

The combination of rehabilitation is suitable for the treatment of respiratory failure patients with clear causes of phrenic nerve injury. For patients with unexplained causes, rehabilitation could also be performed before the diagnosis. Patients with irreversible injury need long-term and family rehabilitation prescriptions.

Risk of Acute Respiratory Distress Syndrome in Community-Acquired Pneumonia Patients: Use of an Artificial Neural Network Model

This study aimed to explore the independent risk factors for community-acquired pneumonia (CAP) complicated with acute respiratory distress syndrome (ARDS) and to predict and evaluate the risk of ARDS in CAP patients based on artificial neural network models (ANNs). We retrospectively analyzed eligible 989 CAP patients (632 men and 357 women) who met the criteria from the comprehensive intensive care unit (ICU) and the respiratory and critical care medicine department of Changzhou Second People's Hospital, Jiangsu Provincial People's Hospital, Nanjing Military Region General Hospital, and Wuxi Fifth People's Hospital between February 2018 and February 2021. The best predictors to model the ANNs were selected from 51 variables measured within 24 h after admission. By using this model, patients were divided into a training group (n = 701) and a testing group (n = 288 patients). Results showed that in 989 CAP patients, 22 important variables were identified as risk factors. The sensitivity, specificity, and accuracy of the ANNs model training group were 88.9%, 90.1%, and 89.7%, respectively. When ANNs were used in the test group, their sensitivity, specificity, and accuracy were 85.0%, 87.3%, and 86.5%, respectively; when ANNs were used to predict ARDS, the area under the receiver operating characteristic (ROC) curve was 0.943 (95% confidence interval (0.918-0.968)). The nine most important independent variables affecting the ANNs models were lactate dehydrogenase (100%), activated partial thromboplastin time (84.6%), procalcitonin (83.8%), age (77.9%), maximum respiratory rate (76.0%), neutrophil (75.9%), source of admission (68.9%), concentration of total serum kalium (61.3%), and concentration of total serum bilirubin (50.4%) (all important >50%). The ANNs model and the logistic regression models were significantly different in predicting and evaluating ARDS in CAP patients. Thus, the ANNs model has a good predictive value in predicting and evaluating ARDS in CAP patients, and its performance is better than that of the logistic regression model in predicting the incidence of ARDS patients.

EVs vs. EVs: MSCs and Tregs as a source of invisible possibilities

Extracellular vesicles (EVs) are produced by various cells and exist in most biological fluids. They play an important role in cell-cell signaling, immune response, and tumor metastasis, and also have theranostic potential. They deliver many functional biomolecules, including DNA, microRNAs (miRNA), messenger RNA (mRNA), long non-coding RNA (lncRNA), lipids, and proteins, thus affecting different physiological processes in target cells. Decreased immunogenicity compared to liposomes or viral vectors and the ability to cross through physiological barriers such as the blood-brain barrier make them an attractive and innovative option as diagnostic biomarkers and therapeutic carriers. Here, we highlighted two types of cells that can produce functional EVs, namely, mesenchymal stem/stromal cells (MSCs) and regulatory T cells (Tregs), discussing MSC/Treg-derived EV-based therapies for some specific diseases including acute respiratory distress syndrome (ARDS), autoimmune diseases, and cancer.

Design, synthesis, and bioactivity evaluation of novel 1-(4-(benzylsulfonyl)-2-nitrophenyl) derivatives as potential anti-inflammatory agents against LPS-induced acute lung injury

Acute lung injury (ALI) is a devastating disease with a high mortality rate of 30%-40%. There is an unmet clinical need owing to limited treatment strategies and little clinical benefit. The pathology of ALI indicates that reducing the inflammatory response could be a highly desirable strategy to treat ALI. In this study, we designed and synthesized 36 novel 1-(4-(benzylsulfonyl)-2-nitrophenyl) derivatives and evaluated their anti-inflammatory activities by measuring the release of cytokines in lipopolysaccharide (LPS)-challenged J774A.1 cells. Compounds 19, 20, and 39 potently reduced the release of IL-6 and TNF-α in J774A.1 cells. Additionally, 39 improved LPS-induced ALI in vivo and inhibited cytokine production in lung tissues. Furthermore, 39 reduced inflammatory infiltration and downregulated p-p65 levels in lung tissues. Thus, compound 39 could serve as a new lead structure for the development of anti-inflammatory drugs to treat ALI.

siRNA-Mediated Timp1 Silencing Inhibited the Inflammatory Phenotype during Acute Lung Injury

Acute lung injury is a complex cascade process that develops in response to various damaging factors, which can lead to acute respiratory distress syndrome. Within this study, based on bioinformatics reanalysis of available full-transcriptome data of acute lung injury induced in mice and humans by various factors, we selected a set of genes that could serve as good targets for suppressing inflammation in the lung tissue, evaluated their expression in the cells of different origins during LPS-induced inflammation, and chose the tissue inhibitor of metalloproteinase Timp1 as a promising target for suppressing inflammation. We designed an effective chemically modified anti-TIMP1 siRNA and showed that Timp1 silencing correlates with a decrease in the pro-inflammatory cytokine IL6 secretion in cultured macrophage cells and reduces the severity of LPS-induced acute lung injury in a mouse model.

Early and Dose-Dependent Xenogeneic Mesenchymal Stem Cell Therapy Improved Outcomes in Acute Respiratory Distress Syndrome Rodent Through Ameliorating Inflammation, Oxidative Stress, and Immune Reaction

This study tested whether human umbilical cord-derived mesenchymal stem cells (HUCDMSCs) treatment effectively protected the rat lung against acute respiratory distress syndrome (ARDS) injury, and benefits of early and dose-dependent treatment. Rat pulmonary epithelial cell line L2 (PECL2) were categorized into G1 (PECL2), G2 (PECL2 + healthy rat lung-derived extraction/50 mg/ml co-cultured for 24 h), G3 (PECL2 + ARDS rat lung-derived extraction/50 mg/ml co-cultured for 24 h), and G4 (condition as G3 + HUCDMSCs/1 × 105/co-cultured for 24 h). The result showed that the protein expressions of inflammatory (HMGB-1/TLR-2/TLR-4/MAL/TRAM/MyD88/TRIF/TRAF6/IkB/NF-κB/IL-1β/TNF-α), oxidative-stress/mitochondrial-damaged (NOX-1/NOX-2/ASK1/p-MKK4/p-MKK7/JNKs/JUN/cytosolic-cytochrome-C/cyclophilin-D/DRP1), and cell-apoptotic/fibrotic (cleaved-caspase 3/cleaved-PARP/TGF-β/p-Smad3) biomarkers were significantly increased in G3 than in G1/G2 and were significantly reversed in G4 (all P < 0.001), but they were similar between G1/G2. Adult male rats (n = 42) were equally categorized into group 1 (normal control), group 2 (ARDS only), group 3 [ARDS + HUCDMSCs/1.2 × 106 cells intravenous administration at 3 h after 48 h ARDS induction (i.e., early treatment)], group 4 [ARDS + HUCDMSCs/1.2 × 106 cells intravenous administration at 24 h after 48 h ARDS induction (late treatment)], and group 5 [ARDS + HUCDMSCs/1.2 × 106 cells intravenous administration at 3 h/24 h after-48 h ARDS induction (dose-dependent treatment)]. By day 5 after ARDS induction, the SaO2%/immune regulatory T cells were highest in group 1, lowest in group 2, significantly lower in group 4 than in groups 3/5, and significantly lower in group 3 than in group 5, whereas the circulatory/bronchioalveolar lavage fluid inflammatory cells (CD11b-c+/LyG6+/MPO+)/circulatory immune cells (CD3-C4+/CD3-CD8+)/lung-leakage-albumin level/lung injury score/lung protein expressions of inflammatory (HMGB-1/TLR-2/TLR-4/MAL/TRAM/MyD88/TRIF/TRAF6/IκB-β/p-NF-κB/IL-1β/TNF-α)/fibrotic (p-SMad3/TGF-β), apoptosis (mitochondrial-Bax/cleaved-caspase-3)/oxidative-cell-stress (NOX-1/NOX-2/ASK1/p-MKK4/p-MKK7/p-JNKs/p-cJUN)/mitochondrial damaged (cyclophilin-D/DRP1/cytosolic-cytochrome-C) biomarkers displayed an opposite pattern of SaO2% among the groups (all P < 0.0001). Early administration was superior to and two-dose counterpart was even more superior to late HUCDMSCs treatment for protecting the lung against ARDS injury.

Knockdown of SHP2 attenuated LPS-induced ferroptosis via downregulating ACSL4 expression in acute lung injury

BACKGROUND

Acute lung injury (ALI) is a complex disease with a high mortality. Src homology 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2) is a protein tyrosine phosphatase that participates in pathogenesis of multiple diseases. Nevertheless, the role of SHP2 in ALI remains unknown.

METHODS

The in vivo and in vitro lipopolysaccharide (LPS)-induced ALI models were successfully established. The histopathological changes were evaluated by hematoxylin and eosin staining. The vascular permeability of lungs was assessed by Evans blue assay. The expression of ACSL4 and SHP2 was detected by western blot and qRT-PCR assay. The lactate dehydrogenase (LDH) activity, malondialdehyde (MDA), iron, and glutathione (GSH) levels were measured by commercial kits.

RESULTS

The SHP2 was upregulated in LPS-induced ALI mice and LPS-stimulated MLE-12 cells. In loss-of function experiment, the knockdown of SHP2 attenuated LPS-induced lung injury, microvessels damage, pulmonary edema, and increase of lung vascular permeability in vivo. Mechanically, shSHP2-rescued LPS induced increase in LDH activity, MDA, and iron levels, and decrease in GSH levels, as well as the accumulation of reactive oxygen species in vivo and in vitro, leading to an alleviation of LPS-induced ferroptosis. Notably, shSHP2 reduced the expression of Acyl-CoA synthetase long-chain 4 (ACSL4). In the rescued experiments, overexpression of ACSL4 abolished the shSHP2-induced reduction of LDH activity, MDA, and iron levels, and increase in GSH levels, thereby aggravating the LPS-induced ferroptosis.

CONCLUSION

These findings concluded that the knockdown of SHP2 attenuated LPS-induced ferroptosis via downregulation of ACSL4 expression in ALI, providing a novel sight for ALI treatment.

rmMANF prevents sepsis-associated lung injury via inhibiting endoplasmic reticulum stress-induced ferroptosis in mice

Ferroptosis plays a critical role in LPS-induced acute lung injury and is modulated by endoplasmic reticulum stress (ERS). As a typical ER stress-responsive protein, recently mesencephalic astrocyte-derived neurotrophic factor (MANF) has been demonstrated to attenuate LPS-induced acute lung injury (ALI) through repressing macrophage activation. However, whether MANF exerts a preventive role on ferroptosis and excess ER stress remains unclear. Here, we first built a protein-protein interaction (PPI) network to obtain potential interacting proteins related to MANF through STRING and GeneMANIA. Then, male C57BL/6J mice were used to build a model of LPS-induced lung injury. Two days before LPS injection, the tail vein injected recombinant murine MANF (rmMANF) at 750 μg/kg. Twenty-four hours after the LPS injection, the histopathological changes and damage in the lung tissues were detected and scored by HE staining and TUNEL assay, respectively. Endogenous MANF levels, oxidative stress markers (GSH, SOD, CAT, and MDA), ERS markers (GRP78, PERK, and ATF4), and the ferroptosis markers (iron, GPX4, and 4-HNE) in the lung tissues were measured by IHC, western blotting, and commercial kits. Our results showed that LPS induced significant lung injury to the increase in MPO, MDA, and 4-HNE, a decrease in GPX4 and GSH, SOD, CAT, and total iron accumulation in LPS-exposed mice. Simultaneously, GRP78/PERK/ATF4 pathway was notably activated by LPS, accompanied by the down-regulation of MANF. Furthermore, rmMANF pretreatment markedly prevented LPS-induced lung tissue injury and ferroptosis characteristics with the increased GPX4 level in sepsis mice. Finally, we found that LPS-induced oxidative stress and activation of the GRP78/PERK/ATF4 pathway were significantly restrained by rmMANF pretreatment, except for endogenous MANF level. Overall, rmMANF pretreatment can prevent sepsis-associated lung injury by inhibiting ER stress-induced ferroptosis in mice.

The Role of Pulmonary Surfactant Phospholipids in Fibrotic Lung Diseases

Diffuse parenchymal lung diseases (DPLD) or Interstitial lung diseases (ILD) are a heterogeneous group of lung conditions with common characteristics that can progress to fibrosis. Within this group of pneumonias, idiopathic pulmonary fibrosis (IPF) is considered the most common. This disease has no known cause, is devastating and has no cure. Chronic lesion of alveolar type II (ATII) cells represents a key mechanism for the development of IPF. ATII cells are specialized in the biosynthesis and secretion of pulmonary surfactant (PS), a lipid-protein complex that reduces surface tension and minimizes breathing effort. Some differences in PS composition have been reported between patients with idiopathic pulmonary disease and healthy individuals, especially regarding some specific proteins in the PS; however, few reports have been conducted on the lipid components. This review focuses on the mechanisms by which phospholipids (PLs) could be involved in the development of the fibroproliferative response.

Inositol Alleviates Pulmonary Fibrosis by Promoting Autophagy via Inhibiting the HIF-1α-SLUG Axis in Acute Respiratory Distress Syndrome

The effective remission of acute respiratory distress syndrome- (ARDS-) caused pulmonary fibrosis determines the recovery of lung function. Inositol can relieve lung injuries induced by ARDS. However, the mechanism of myo-inositol in the development of ARDS is unclear, which limits its use in the clinic. We explored the role and mechanism of myo-inositol in the development of ARDS by using an in vitro lipopolysaccharide- (LPS-) established alveolar epithelial cell inflammation model and an in vivo ARDS mouse model. Our results showed that inositol can alleviate the progression of pulmonary fibrosis. More significantly, we found that inositol can induce autophagy to inhibit the progression pulmonary fibrosis caused by ARDS. In order to explore the core regulators of ARDS affected by inositol, mRNA-seq sequencing was performed. Those results showed that transcription factor HIF-1α can regulate the expression of SLUG, which in turn can regulate the key gene E-Cadherin involved in cell epithelial-mesenchymal transition (EMT) as well as N-cadherin expression, and both were regulated by inositol. Our results suggest that inositol activates autophagy to inhibit EMT progression induced by the HIF-1α/SLUG signaling pathway in ARDS, and thereby alleviates pulmonary fibrosis.

Pharmacologic therapies of ARDS: From natural herb to nanomedicine

Acute respiratory distress syndrome (ARDS) is a common critical illness in respiratory care units with a huge public health burden. Despite tremendous advances in the prevention and treatment of ARDS, it remains the main cause of intensive care unit (ICU) management, and the mortality rate of ARDS remains unacceptably high. The poor performance of ARDS is closely related to its heterogeneous clinical syndrome caused by complicated pathophysiology. Based on the different pathophysiology phases, drugs, protective mechanical ventilation, conservative fluid therapy, and other treatment have been developed to serve as the ARDS therapeutic methods. In recent years, there has been a rapid development in nanomedicine, in which nanoparticles as drug delivery vehicles have been extensively studied in the treatment of ARDS. This study provides an overview of pharmacologic therapies for ARDS, including conventional drugs, natural medicine therapy, and nanomedicine. Particularly, we discuss the unique mechanism and strength of nanomedicine which may provide great promises in treating ARDS in the future.

Progress in preclinical studies of macrophage autophagy in the regulation of ALI/ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with high morbidity and mortality that poses a major challenge in critical care medicine. The development of ALI/ARDS involves excessive inflammatory response, and macrophage autophagy plays an important role in regulating the inflammatory response in ALI/ARDS. In this paper, we review the effects of autophagy in regulating macrophage function, discuss the roles of macrophage autophagy in ALI/ARDS, and highlight drugs and other interventions that can modulate macrophage autophagy in ALI/ARDS to improve the understanding of the mechanism of macrophage autophagy in ALI/ARDS and provide new ideas and further research directions for the treatment of ALI/ARDS.

Application of Visual Artificial Airway in Patients with ARDS Assisted by Pulmonary Ultrasound

Objective

To explore the application of pulmonary ultrasound in visual nursing of artificial airway in patients with acute respiratory distress syndrome (ARDS).

Methods

Seventy-eight ARDS patients with mechanical ventilation admitted from February 2021 to January 2022 were included and divided into the intervention group and the control group. The control group was given routine airway nursing, and the intervention group was given visual airway nursing management through lung ultrasound. The arterial blood gas analysis indexes, mechanical ventilation time, ICU treatment time, total hospitalization time, aspiration, and the incidence of ventilator-associated pneumonia (VAP) were compared between the two groups.

Results

After treatment, PaO2, PaCO2, SPO2, and oxygenation indexes were significantly improved compared with those before treatment, and the indexes in the intervention group were better than those in the control group after treatment, and the differences were statistically significant (P < 0.05). The mechanical ventilation time (5.39 ± 0.68 vs. 7.92 ± 0.59 days), ICU treatment time (8.05 ± 1.14 vs. 10.71 ± 1.16 days), and total hospitalization time (12.05 ± 2.20 vs. 15.68 ± 2.18 days) in the intervention group were significantly shorter than those in the control group (P < 0.05). The incidences of aspiration (2.56% vs. 15.38%) and VAP (5.13% vs. 20.51%) in the intervention group was significantly lower than that in the control group (P < 0.05).

Conclusion

The application of visual artificial airway management assisted by lung ultrasound in ARDS patients can shorten the treatment time and hospitalization time of mechanical ventilation, reduce the incidence of aspiration and VAP, and improve the prognosis of patients.

Meta-Analysis of the Effect of Glucocorticoids on Adult Acute Respiratory Distress Syndrome

Objectives

The aim of this study is to investigate the effect of glucocorticoids in adult patients with acute respiratory distress syndrome (ARDS) by meta-analysis.

Methods

PubMed, Cochrane Library, Embase, CNKI, Wanfang Database, and Chinese Biomedical literature database were searched. A randomized controlled trial (RCTS) on glucocorticoid therapy in adult patients with ARDS was conducted from the time of database construction to December 2021. The content is about the randomized controlled trial (RCT) of glucocorticoid treatment for adult patients with ARDS, without limiting the dose and course of glucocorticoid treatment. The quality of the included RCTS was evaluated by using the bias risk assessment tool of the Cochrane Collaboration network, and the basic information, clinical features, and target outcomes of the literature were extracted. The effects of glucocorticoids on mortality and oxygenation index (PaO₂/FiO₂) in adult ARDS patients were evaluated by meta-analysis.

Results

A total of 1,441 ARDS patients in 10 RCTs were finally included, including 734 patients in the glucocorticoid treatment group (hormone group) and 707 patients in the conventional treatment group (control group). The 10 studies included have a good overall design and high quality. Compared with controls, glucocorticoid use was significantly associated with a decrease in mortality in adult ARDS patients (relative risk (RR) = 0.73, 95% confidence interval (95% CI) = 0.59–0.90, P = 0.003). Analysis showed that glucocorticoids significantly reduced the mortality in ARDS patients treated with medium and low doses of steroids (RR = 0.73, 95% CI = 0.58–0.92, P = 0.007). In patients with early administration of steroids, intervention with glucocorticoids was significantly associated with the decreased mortality in adult ARDS patients compared with controls (RR = 0.74, 95% CI 0.56–0.99, P = 0.04). Among patients with more than 7 days of hormone therapy, treatment with glucocorticoids was significantly associated with decreased mortality in adult ARDS patients (RR = 0.66, 95% CI = 0.50–0.88, P = 0.005) compared with controls. Glucocorticoids tended to improve PaO₂/FiO₂ in adult ARDS patients compared with controls, but the difference was not statistically significant (weighted mean difference (WMD) = 11.60, 95% = CI = 15.02–38.22, P = 0.39).

Conclusion

Glucocorticoid therapy can reduce mortality in adult ARDS patients, and the benefit is more pronounced in patients with medium- and low-dose hormone therapy, early hormone administration, and hormone therapy for more than 7 days. However, no improvement in PaO₂/FiO₂ by glucocorticoid treatment was found, which needs to be confirmed by further studies.

Advances in the use of exosomes for the treatment of ALI/ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with high morbidity and mortality. Currently, the primary treatment for ALI/ARDS is mainly symptomatic therapy such as mechanical ventilation and fluid management. Due to the lack of effective treatment strategies, most ALI/ARDS patients face a poor prognosis. The discovery of exosomes has created a promising prospect for the treatment of ALI/ARDS. Exosomes can exert anti-inflammatory effects, inhibit apoptosis, and promote cell regeneration. The microRNA contained in exosomes can participate in intercellular communication and play an immunomodulatory role in ALI/ARDS disease models. This review discusses the possible mechanisms of exosomes in ALI/ARDS to facilitate the development of innovative treatments for ALI/ARDS.

Nanoscale Porphyrin Metal-Organic Frameworks Deliver siRNA for Alleviating Early Pulmonary Fibrosis in Acute Lung Injury

Acute lung injury (ALI) has high mortality and still lacks novel and efficient therapies. Zinc finger E-box binding homeobox 1 and 2 (ZEB1/2) are highly expressed in the early stage of ALI and are positively correlated with the progression of pulmonary fibrosis. Herein, we developed a nanoscale Zr(IV)-based porphyrin metal-organic (ZPM) framework to deliver small interfering ZEB1/2 (siZEB1/2) to alleviate early pulmonary fibrosis during ALI. This pH-responsive nano-ZPM system could effectively protect siRNAs during lung delivery until after internalization and rapidly trigger siRNA release under the mildly acidic environment of the endo/lysosome (pH 4.0–6.5) for transfection and gene silencing. Furthermore, the in vivo studies confirmed that this nano-ZPM system could anchor in inflamed lungs. Moreover, the ZEB1/2 silencing led to increased E-cadherin and decreased α-SMA levels. Overall, the nano-ZPM system was an excellent non-viral vector system to deliver siRNAs to alleviate early pulmonary fibrosis during ALI.

Advances in the Regulation of Macrophage Polarization by Mesenchymal Stem Cells and Implications for ALI/ARDS Treatment

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a common condition with high mortality. ALI/ARDS is caused by multiple etiologies, and the main clinical manifestations are progressive dyspnea and intractable hypoxemia. Currently, supportive therapy is the main ALI/ARDS treatment, and there remains a lack of targeted and effective therapeutic strategies. Macrophages are important components of innate immunity. M1 macrophages are pro-inflammatory, while M2 macrophages are anti-inflammatory and promote tissue repair. Mesenchymal stem cells (MSCs) are stem cells with broad application prospects in tissue regeneration due to their multi-directional differentiation potential along with their anti-inflammatory and paracrine properties. MSCs can regulate the balance of M1/M2 macrophage polarization to improve the prognosis of ALI/ARDS. In this paper, we review the mechanisms by which MSCs regulate macrophage polarization and the signaling pathways associated with polarization. This review is expected to provide new targets for the treatment of ALI/ARDS.

Metabolomics profile in acute respiratory distress syndrome by nuclear magnetic resonance spectroscopy in patients with community-acquired pneumonia

Background

Acute respiratory distress syndrome (ARDS) is a challenging clinical problem. Discovering the potential metabolic alterations underlying the ARDS is important to identify novel therapeutic target and improve the prognosis. Serum and urine metabolites can reflect systemic and local changes and could help understanding metabolic characterization of community-acquired pneumonia (CAP) with ARDS.

Methods

Clinical data of patients with suspected CAP at the First Affiliated Hospital of Wenzhou Medical University were collected from May 2020 to February 2021. Consecutive patients with CAP were enrolled and divided into two groups: CAP with and without ARDS groups. ¹H nuclear magnetic resonance-based metabolomics analyses of serum and urine samples were performed before and after treatment in CAP with ARDS (n = 43) and CAP without ARDS (n = 45) groups. Differences metabolites were identifed in CAP with ARDS. Furthermore, the receiver operating characteristic (ROC) curve was utilized to identify panels of significant metabolites for evaluating therapeutic effects on CAP with ARDS. The correlation heatmap was analyzed to further display the relationship between metabolites and clinical characteristics.

Results

A total of 20 and 42 metabolites were identified in the serum and urine samples, respectively. Serum metabolic changes were mainly involved in energy, lipid, and amino acid metabolisms, while urine metabolic changes were mainly involved in energy metabolism. Elevated levels of serum 3-hydroxybutyrate, lactate, acetone, acetoacetate, and decreased levels of serum leucine, choline, and urine creatine and creatinine were detected in CAP with ARDS relative to CAP without ARDS. Serum metabolites 3-hydroxybutyrate, acetone, acetoacetate, citrate, choline and urine metabolite 1-methylnicotinamide were identified as a potential biomarkers for assessing therapeutic effects on CAP with ARDS, and with AUCs of 0.866 and 0.795, respectively. Moreover, the ROC curve analysis revealed that combined characteristic serum and urine metabolites exhibited a better classification system for assessing therapeutic effects on CAP with ARDS, with a AUC value of 0.952. In addition, differential metabolites strongly correlated with clinical parameters in patients with CAP with ARDS.

Conclusions

Serum- and urine-based metabolomics analyses identified characteristic metabolic alterations in CAP with ARDS and might provide promising circulatory markers for evaluating therapeutic effects on CAP with ARDS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02075-w.

Correlation of small nucleolar RNA host gene 16 with acute respiratory distress syndrome occurrence and prognosis in sepsis patients

Background

Long noncoding RNA small nucleolar RNA host gene 16 (lnc‐SNHG16) regulates sepsis‐induced acute lung injury and inflammation, which is involved in the pathophysiology of acute respiratory distress syndrome (ARDS). The present study intended to explore the role of lnc‐SNHG16 as a potential biomarker indicating ARDS risk, disease severity, inflammation, and mortality in sepsis.

Methods

Peripheral blood mononuclear cell (PBMC) samples were collected from 160 sepsis patients within 24 hours after admission and 30 healthy controls (HCs). Then, lnc‐SNHG16 in PBMCs was detected by reverse transcription‐quantitative polymerase chain reaction. Sepsis patients were followed up until death or up to 28 days.

Results

lnc‐SNHG16 was declined in sepsis patients compared with HCs (p < 0.001). The incidence of ARDS was 27.5% among sepsis patients; meanwhile, sepsis patients with ARDS had higher mortality than those without ARDS (p < 0.001). Furthermore, lnc‐SNHG16 was declined in sepsis patients with ARDS compared to those without ARDS (p < 0.001); besides, higher lnc‐SNHG16 was independently correlated with declined ARDS occurrence in sepsis patients (p = 0.001), while primary respiratory infection and higher CRP were independently correlated with elevated ARDS occurrence in sepsis patients (both p < 0.05). Moreover, a negative correlation was found in lnc‐SNHG16 with history of diabetes, history of chronic obstructive pulmonary disease, and APACHE II and SOFA scores (all p < 0.05). Additionally, lnc‐SNHG16 was declined in sepsis deaths compared with survivors (p = 0.002), while it was not independently linked with sepsis mortality.

Conclusion

lnc‐SNHG16 correlates with lower ARDS occurrence and better prognosis in sepsis patients.

Differential Prognostic Analysis of Higher and Lower PEEP in ARDS Patients: Systematic Review and Meta-Analysis

Background

Positive end-expiratory pressure (PEEP) refers to the positive pressure in the respiratory tract at the end of the exhalation when we use a ventilator. The differences of higher PEEP and lower PEEP on clinical outcomes in acute respiratory distress syndrome (ARDS) patients are less well known.

Methods

A comprehensive literature search of all randomized control trials (RCTs) was conducted using PubMed, Embase, World Health Organization (WHO) Global Index Medicus, WHO clinical trial registry, and Clinicaltrials.gov. Inclusion criteria included RCTs comparing the clinical outcomes of higher and lower PEEP in ARDS patients.

Results

Eleven studies were included in the final analysis. In the higher PEEP group, the hospital mortality, 28-day mortality, and ICU mortality showed no significantly lower risk compared to the lower PEEP group (RR = 0.92, 95% CI 0.80-1.05, p = 0.22; RR = 0.88, 95% CI 0.73-1.05, p = 0.15; RR = 0.84, 95% CI 0.67-1.05, p = 0.12; respectively). High certainty could be obtained that there is no significant difference between the clinical outcomes of higher PEEP and lower PEEP in ARDS patients.

Conclusions

There is no significant difference of the hospital mortality, 28-day mortality, and ICU mortality between higher and lower PEEP in ARDS patients.

The suppressive effects of Mer inhibition on inflammatory responses in the pathogenesis of LPS-induced ALI/ARDS

The pathogenesis of sepsis-induced acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) has not yet been fully elucidated. Growth arrest-specific 6 (Gas6) has marked effects on hemostasis and reduces inflammation through its interaction with receptor tyrosine kinases of the TAM family: Tyro3, Axl, and Mer. Here, we found that plasma concentrations of Gas6 and soluble Mer were greater in patients with severe sepsis or septic ALI/ARDS compared with those in normal healthy donors. To determine whether the Gas6-Mer axis was critical in the pathogenesis of ALI/ARDS, we investigated the effects of intravenous administration of the selective Mer inhibitor UNC2250 on lipopolysaccharide (LPS)-induced ALI in mouse models subjected to inhalation of LPS. UNC2250 markedly inhibited the infiltration into the lungs of neutrophils and monocytes with increased amounts of Gas6 and Mer proteins, severe lung damage, and increased amounts of reactive oxygen species (ROS) in LPS-induced ALI in mice. In human pulmonary aortic endothelial cells, LPS induced decreases in the amounts of endothelial nitric oxide synthase, thrombomodulin, and vascular endothelial-cadherin, which was blocked by treatment with UNC2250. UNC2250 also inhibited the LPS-dependent increases in cell proliferation and enhanced apoptosis in HL-60 cells, a human neutrophil-like cell line, and RAW264.7 cells, a mouse monocyte/macrophage cell line. These data provide insights into the potential multiple beneficial effects of the Mer inhibitor UNC2250 as a therapeutic reagent to treat inflammatory responses in ALI/ARDS.

PARP-1 Inhibition Repressed Imbalance of Th17 and Treg Cells in Preterm Rats with Intrauterine Infection-Induced Acute Respiratory Distress Syndrome by Reducing the Expression Level of IL-6

Background. Abundant reports have uncovered an imbalance of Treg and Th17 cells in pulmonary diseases. Hereon, we intend to explore the impact of PARP-1 on the imbalance of Th17/Treg and the potential mechanism in premature rats with acute respiratory distress syndrome (ARDS). Methods. Preterm ARDS infants and healthy term infants were enrolled in this investigation. To induce a rat model of ARDS, E.coli suspension was given to rats through two vaginal dilator-guided intramuscular injections. H&E staining was used to perform histopathological examination. Flow cytometry was employed to assess the proportion of Th17 or Treg cells accounted for CD4+ T cells. ELISA was applied to measure levels of IL-6, IL-17A, and IL-10 in the serum of ARDS patients. Moreover, the mRNA and protein expression levels of PARP-1, IL-6, IL-17A, and IL-10 were detected through qRT-PCR and western blotting. Results. An increased Th17/Treg ratio was observed in preterm infants and rats with ARDS. The PARP-1 expression level was raised in the lung tissues of ARDS rats, and PARP-1 downregulation alleviated E.coli-induced lung injury in preterm rats. Expression levels of PARP-1, IL-6, and IL-17A were raised, and the IL-10 level was reduced in the lung tissues of rats after E.coli treatment, which was all reversed by PARP-1 suppression. Importantly, the ratio of Th17/Treg differentiated from purified CD4+ T cells of the E.coli + PARP-1 inhibitor group was elevated by recombinant IL-6. Conclusion. PARP-1 downregulation repressed the imbalance of Th17 and Treg cells via reducing the expression level of IL-6, implying that PARP-1 may be a promising target for ARDS therapy.

Pulmonary delivery of siRNA against acute lung injury/acute respiratory distress syndrome

The use of small interfering RNAs (siRNAs) has been under investigation for the treatment of several unmet medical needs, including acute lung injury/acute respiratory distress syndrome (ALI/ARDS) wherein siRNA may be implemented to modify the expression of pro-inflammatory cytokines and chemokines at the mRNA level. The properties such as clear anatomy, accessibility, and relatively low enzyme activity make the lung a good target for local siRNA therapy. However, the translation of siRNA is restricted by the inefficient delivery of siRNA therapeutics to the target cells due to the properties of naked siRNA. Thus, this review will focus on the various delivery systems that can be used and the different barriers that need to be surmounted for the development of stable inhalable siRNA formulations for human use before siRNA therapeutics for ALI/ARDS become available in the clinic.

New Insights into the Role of the Complement System in Human Viral Diseases

The complement system (CS) is part of the human immune system, consisting of more than 30 proteins that play a vital role in the protection against various pathogens and diseases, including viral diseases. Activated via three pathways, the classical pathway (CP), the lectin pathway (LP), and the alternative pathway (AP), the complement system leads to the formation of a membrane attack complex (MAC) that disrupts the membrane of target cells, leading to cell lysis and death. Due to the increasing number of reports on its role in viral diseases, which may have implications for research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), this review aims to highlight significant progress in understanding and defining the role of the complement system in four groups of diseases of viral etiology: (1) respiratory diseases; (2) acute liver failure (ALF); (3) disseminated intravascular coagulation (DIC); and (4) vector-borne diseases (VBDs). Some of these diseases already present a serious global health problem, while others are a matter of concern and require the collaboration of relevant national services and scientists with the World Health Organization (WHO) to avoid their spread.

Quest for breathing: proliferation of alveolar type 1 cells

There is much evidence that the vertebrate lung originated from a progenitor structure which was present in bony fish. However, critical basic elements for the evolution of breathing in tetrapods, such as the central rhythm generator sensitive to CO₂/pH and the pulmonary surfactant, were present in the lungless primitive vertebrate. This suggests that the evolution of air breathing in all vertebrates may have evolved through exaptations. It appears that the capability for proliferation of alveolar type 1 (AT1) cells is the "critical factor" which rendered possible the most radical subsequent innovation-the possibility of air breathing. "Epithelial remodeling," which consists in proliferation of alveolar cells-the structural basis for gas diffusion-observed in the alimentary tract of the gut-breathing fishes (GBF) has great potential for application in biomedical research. Such a process probably led to the gradual evolutionary development of lungs in terrestrial vertebrates. Research on the cellular and molecular mechanisms controlling proliferation of squamous epithelial cells in the GBF should contribute to explaining the regeneration-associated phenomena that occur in mammal lungs, and especially to the understanding of signal pathways which govern the process.

The pathophysiology of sepsis - 2021 update: Part 2, organ dysfunction and assessment

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

This is the second article in a 2-part series discussing the pathophysiology of sepsis. Part 1 of the series reviewed the immunologic response and overlapping pathways of inflammation and coagulation that contribute to the widespread organ dysfunction. In this article (part 2), major organ systems and their dysfunction in sepsis are reviewed, with discussion of scoring systems used to identify patterns and abnormal vital signs and laboratory values associated with sepsis.

SUMMARY

Sepsis is a dysregulated host response to infection that produces significant morbidity, and patients with shock due to sepsis have circulatory and cellular and metabolic abnormalities that lead to a higher mortality. Cardiovascular dysfunction produces vasodilation, reduced cardiac output and hypotension/shock requiring fluids, vasopressors, and advanced hemodynamic monitoring. Respiratory dysfunction may require mechanical ventilation and attention to volume status. Renal dysfunction is a frequent manifestation of sepsis. Hematologic dysfunction produces low platelets and either elevation or reduction of leucocytes, so consideration of the neutrophil:lymphocyte ratio may be useful. Procoagulant and antifibrinolytic activity leads to coagulation that is stimulated by inflammation. Hepatic dysfunction manifest as elevated bilirubin is often a late finding in sepsis and may cause reductions in production of essential proteins. Neurologic dysfunction may result from local endothelial injury and systemic inflammation through activity of the vagus nerve.

CONCLUSION

Timely recognition and team response with efficient use of therapies can improve patient outcome, and pharmacists with a complete understanding of the pathophysiologic mechanisms and treatments are valuable members of that team.

Reference Gene Selection for Gene Expression Analyses in Mouse Models of Acute Lung Injury

qRT-PCR still remains the most widely used method for quantifying gene expression levels, although newer technologies such as next generation sequencing are becoming increasingly popular. A critical, yet often underappreciated, problem when analysing qRT-PCR data is the selection of suitable reference genes. This problem is compounded in situations where up to 25% of all genes may change (e.g., due to leukocyte invasion), as is typically the case in ARDS. Here, we examined 11 widely used reference genes for their suitability in commonly used models of acute lung injury (ALI): ventilator-induced lung injury (VILI), in vivo and ex vivo, lipopolysaccharide plus mechanical ventilation (MV), and hydrochloric acid plus MV. The stability of reference gene expression was determined using the NormFinder, BestKeeper, and geNorm algorithms. We then proceeded with the geNorm results because this is the only algorithm that provides the number of reference genes required to achieve normalisation. We chose interleukin-6 (Il-6) and C-X-C motif ligand 1 (Cxcl-1) as the genes of interest to analyse and demonstrate the impact of inappropriate normalisation. Reference gene stability differed between the ALI models and even within the subgroup of VILI models, no common reference gene index (RGI) could be determined. NormFinder, BestKeeper, and geNorm produced slightly different, but comparable results. Inappropriate normalisation of Il-6 and Cxcl1 gene expression resulted in significant misinterpretation in all four ALI settings. In conclusion, choosing an inappropriate normalisation strategy can introduce different kinds of bias such as gain or loss as well as under- or overestimation of effects, affecting the interpretation of gene expression data.

Early neuromuscular blocking agents for adults with acute respiratory distress syndrome: a systematic review, meta-analysis and meta-regression

OBJECTIVE

To determine whether neuromuscular blocking agents (NMBAs) can decrease the mortality of patients with acute respiratory distress syndrome (ARDS) and improve their clinical outcomes.

DESIGN

Systematic review, meta-analysis and meta-regression.

DATA SOURCES

PubMed, Embase, Cochrane Library, Web of Science and ClinicalTrials.gov.

METHODS

Randomised controlled trials (RCTs) comparing the treatment effect of NMBAs with that of placebo (or traditional treatment) in patients with ARDS were carefully selected. The primary outcome was 90-day mortality. The secondary outcomes were 21-28 days mortality, NMBA-related complications (barotrauma, pneumothorax and intensive care unit (ICU)-acquired muscle weakness), days free of ventilation and days not in the ICU by day 28, Medical Research Council score, Acute Physiology and Chronic Health Evaluation II score and arterial oxygen tension (PaO₂)/fractional inspired oxygen (FiO₂) (at 48 hours and 72 hours). Random-effects meta-regression was used to explore models involving potential moderators. Trial sequential analysis was performed to estimate the cumulative effect on mortality across RCTs.

RESULTS

NMBAs were not associated with reduced 90-day mortality (risk ratio (RR) 0.85; 95% CI 0.66 to 1.09; p=0.20). However, they decreased the 21-28 days mortality (RR 0.71; 95% CI 0.53 to 0.96; p=0.02) and the rates of pneumothorax (RR 0.46; 95% CI 0.28 to 0.77; p=0.003) and barotrauma (RR 0.56; 95% CI 0.37 to 0.86; p=0.008). In addition, NMBAs increased PaO₂/FiO₂ at 48 hours (mean difference (MD) 18.91; 95% CI 4.29 to 33.53; p=0.01) and 72 hours (MD 12.27; 95% CI 4.65 to 19.89; p=0.002). Meta-regression revealed an association between sample size (p=0.042) and short-term mortality. Publication year (p=0.050), sedation strategy (p=0.047) and sample size (p=0.046) were independently associated with PaO₂/FiO₂ at 48 hours.

CONCLUSIONS

In summary, the results suggested that use of NMBAs might reduce 21-28 days mortality, NMBA-related complications and oxygenation. However, NMBAs did not reduce the 90-day mortality of patients with ARDS, which contradicts a previous meta-analysis.

PROSPERO REGISTRATION NUMBER

CRD42019139440.

Renin-Angiotensin System: An Important Player in the Pathogenesis of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is characterized by massive inflammation, increased vascular permeability and pulmonary edema. Mortality due to ARDS remains very high and even in the case of survival, acute lung injury can lead to pulmonary fibrosis. The renin-angiotensin system (RAS) plays a significant role in these processes. The activities of RAS molecules are subject to dynamic changes in response to an injury. Initially, increased levels of angiotensin (Ang) II and des-Arg⁹-bradykinin (DABK), are necessary for an effective defense. Later, augmented angiotensin converting enzyme (ACE) 2 activity supposedly helps to attenuate inflammation. Appropriate ACE2 activity might be decisive in preventing immune-induced damage and ensuring tissue repair. ACE2 has been identified as a common target for different pathogens. Some Coronaviruses, including SARS-CoV-2, also use ACE2 to infiltrate the cells. A number of questions remain unresolved. The importance of ACE2 shedding, associated with the release of soluble ACE2 and ADAM17-mediated activation of tumor necrosis factor-α (TNF-α)-signaling is unclear. The roles of other non-classical RAS-associated molecules, e.g., alamandine, Ang A or Ang 1-9, also deserve attention. In addition, the impact of established RAS-inhibiting drugs on the pulmonary RAS is to be elucidated. The unfavorable prognosis of ARDS and the lack of effective treatment urge the search for novel therapeutic strategies. In the context of the ongoing SARS-CoV-2 pandemic and considering the involvement of humoral disbalance in the pathogenesis of ARDS, targeting the renin-angiotensin system and reducing the pathogen's cell entry could be a promising therapeutic strategy in the struggle against COVID-19.

Risk factors for and predictive nomogram of postoperative hypoxaemia in elderly patients with femoral neck fractures

Objective

To investigate the related risk factors and predictive nomogram of postoperative hypoxaemia in elderly patients with femoral neck fractures.

Methods

This study included patients aged ≥65 years who underwent surgical treatment of acute femoral neck fractures. Univariate and multivariate logistic analyses were performed to determine the incidence of and risk factors for postoperative hypoxaemia. A predictive nomogram was constructed based on the multivariable model. Using the bootstrap method, discrimination was determined by the C-index and calibration plot.

Results

The logistic regression analysis showed that the anaesthesia type, surgical procedure, American Society of Anesthesiologists (ASA) classification, preoperative hypoxaemia occurrence, and age were independent predictors of development of postoperative hypoxaemia. The predictive formula for hypoxaemia was established as follows: hypoxaemia=−0.8668×spinal anaesthesia (whether)+0.1162×nerve anaesthesia (whether)+1.9555×plate/screw fixation (whether)+1.4950×hip replacement (whether)+0.4883×ASA classification+1.7153×preoperative oxygenation index+0.1608×age. With the bootstrap method, the prediction curve fit well with the ideal curve, suggesting that the prediction curve constructed in this study has good predictive ability.

Conclusions

Anaesthesia type, surgical procedure, ASA classification, preoperative hypoxaemia occurrence, and age were risk factors for postoperative hypoxaemia in elderly patients with femoral neck fractures. The predictive nomogram was designed for preoperative assessment of the risk of postoperative hypoxaemia by calculating the risk score.