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

BACKGROUND AND AIM: Sepsis-induced acute lung injury (ALI) is a complex and life-threatening condition lacking specific and efficient clinical treatments. Extracellular histones, identified as a novel type of damage-associated molecular patterns, have been implicated in the inflammatory process of ALI. However, further elucidation is needed regarding the precise mechanism through which extracellular histones induce inflammation. The aim of this study was to investigate whether extracellular histones can activate NLRP3 inflammasome-mediated inflammation in alveolar macrophages (AMs) by affecting TWIK2-dependent potassium efflux. METHODS AND RESULTS: We conducted experiments using cecal ligation and puncture (CLP) C57BL/6 mice and extracellular histone-stimulated LPS-primed MH-S cells. The results demonstrated a significant increase in the levels of extracellular histones in the plasma and bronchoalveolar lavage fluid (BALF) of CLP mice. Furthermore, neutralizing extracellular histone mitigated lung injury and inflammation in CLP-induced ALI mice. In vitro studies confirmed that extracellular histones upregulated the expression of NLRP3 inflammasome activation-related proteins in MH-S cells, and this effect was dependent on increased potassium efflux mediated by the TWIK2 channel on the plasma membrane. Moreover, extracellular histones directly triggered a substantial influx of calcium, leading to increased Rab11 activity and facilitating the trafficking and location of TWIK2 to the plasma membrane. CONCLUSION: These findings underscore the critical role of extracellular histone-induced upregulation of TWIK2 expression on the plasma membrane of alveolar macrophages (AMs). This upregulation leads to potassium efflux and subsequent activation of the NLRP3 inflammasome, ultimately exacerbating lung inflammation and injury during sepsis.

Effect of bilateral low serratus anterior plane block on quality of recovery after trans-subxiphoid robotic thymectomy: Results of a randomized placebo-controlled trial.

Purpose: This study aimed to investigate the impact of ultrasound-guided, bilateral, low level (T8-T9) deep serratus anterior plane (DSAP) blocks on postoperative recovery quality and postoperative analgesia in patients undergoing trans-subxiphoid robotic thymectomy (TRT). Methods: 39 patients undergoing TRT were randomized to receive either low DSAP block under general anesthesia (Group S) or the sham block (Group C) on each side. The primary outcome was the QoR-40 score at postoperative day (POD) 1. Secondary outcomes included numeric rating scale (NRS) scores over time, postoperative 48 hours opioid consumption, QoR-40 scores at POD 2, 30, and 90. Results: The QoR-40 scores on POD1-2 were higher in Group S than in Group C [179.1 (4.9) vs 167.7 (2.8), P < 0.01; 187.7 (4.6) vs 178.1 (3), P < 0.01, respectively]. Pain scores were significantly lower in Group S, both during resting and motion at postoperative 6h, 12h, and 24h (P < 0.05 for each). The total amount of sufentanil consumed in the first 48 h was lower in Group S than in Group C [61.4 (4.9) vs 78.9 (4.6), P < 0.001]. Conclusion: The bilateral low DSAP blocks enhanced the QoR-40 for 2 days postoperatively, relieved postsurgical pain, and reduced opioid consumption during the early postoperative period in patients undergoing TRT.

Rapid postmortem ventilation improves donor lung viability by extending the tolerable warm ischemic time after cardiac death in mice.

Uncontrolled donation after cardiac death (uDCD) contributes little to ameliorating donor lung shortage due to rapidly progressive warm ischemia after circulatory arrest. Here, we demonstrated that nonhypoxia improves donor lung viability in a novel uDCD lung transplant model undergoing rapid ventilation after cardiac death and compared the evolution of ischemia-reperfusion injury to mice that underwent pulmonary artery ligation (PAL). The tolerable warm ischemia time at 37°C was initially determined in mice using a modified PAL model. The donor lung following PAL was also transplanted into syngeneic mice and compared with those that underwent rapid ventilation or no ventilation at 37°C before transplantation. Twenty-four hours following reperfusion, lung histology, [Formula: see text]/[Formula: see text] ratio, and inflammatory mediators were measured. Four hours of PAL had little impact on [Formula: see text]/[Formula: see text] ratio and acute lung injury score in contrast to significant injury induced by 5 h of PAL. Four-hour PAL lungs showed an early myeloid-dominant inflammatory signature when compared with naïve lungs and substantially injured 5 h PAL lungs. In the context of transplantation, unventilated donor lungs showed severe injury after reperfusion, whereas ventilated donor lungs showed minimal changes in [Formula: see text]/[Formula: see text] ratio, histologic score, and expression of inflammatory markers. Taken together, the tolerable warm ischemia time of murine lungs at 37°C can be extended by maintaining alveolar ventilation for up to 4 h. Nonhypoxic lung undergoing warm ischemia-reperfusion injury shows an early transcriptional signature of myeloid cell recruitment and extracellular matrix proteolysis before blood-gas barrier dysfunction and significant tissue damage.

Inhibition of O-glycosylation aggravates GalN/LPS-induced liver injury through activation of ER stress.

OBJECTIVE: O-glycosylation is the most common post-translational modification of proteins, which is involved in many pathophysiological processes including inflammation. Acute liver injury is characterized by an excessive, uncontrolled inflammatory response, but the effects of aberrant O-glycosylation on acute liver injury are yet to explore. Here we aimed to investigate the role of defective O-glycosylation in D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced acute liver damage in mice. MATERIAL AND METHODS: Experimental mice were administrated with an O-glycosylation inhibitor (benzyl-a-GalNac, 5 mg/kg) at 24 h before administration of GalN/LPS. At 12 h after GalN/LPS administration, mice were sacrificed to collect blood and liver samples for further analysis. RESULTS: We found that benzyl-a-GalNac treatment-induced abundant expression of Tn antigen, which is an immature O-glycan representing abnormal O-glycosylation. Benzyl-a-GalNac pretreatment exacerbated considerably GalN/LPS-induced liver damage in mice, evidenced by significantly reduced survival rates, more severe histological alterations, and notable elevation of multiple inflammatory cytokines and chemokines. Mechanistically, benzyl-a-GalNac could trigger endoplasmic reticulum (ER) stress in the liver of mice, demonstrated by the elevated expression of glucose-regulated protein 78 (GRP78) and C/EBP-homologous protein (CHOP), both of which are hallmarks for ER stress. Inhibition of ER stress by 4-phenylbutyric acid (4-PBA) markedly abrogated benzyl-a-GalNac-mediated enhanced hepatotoxicity and systemic inflammation in GalN/LPS-treated mice. CONCLUSIONS: This study demonstrated that inhibition of O-glycosylation caused by benzyl-a-GalNac aggravated GalN/LPS-induced liver damage and systemic inflammation, which may be due to activation of ER stress.

Extracellular histones indicate the prognosis in patients undergoing extracorporeal membrane oxygenation therapy.

INTRODUCTION: Extracellular histones have been recently identified as damage-associated molecular-pattern (DAMP) molecules involved with the pathogenesis of various inflammatory diseases. This study intended to investigate whether extracellular histones can indicate the prognosis in critically ill patients supported by extracorporeal membrane oxygenation (ECMO) therapy. METHODS: A total of 56 patients undergoing ECMO were analysed retrospectively. Median concentrations of extracellular histones in patients before ECMO were assessed and used to divide the patients into two groups (Group 1 <48 µg/ml and Group 2 ⩾48 µg/ml). Mortality rate, Sequential Organ Failure Assessment (SOFA) scores and systemic inflammation were compared between the groups. RESULTS: There were relatively higher concentrations of extracellular histones in Group 2 patients (57.78 µg/ml [48.4, 71.3]) than in Group 1 patients (36.76 µg/ml [28.5, 39.3], p<0.0001). The hospital mortality rate was 55.4% for the entire study subjects, with significantly worsened mortality in Group 2 in contrast to Group 1 (58.8% vs. 50%, p=0.031). Moreover, Group 2 patients had significantly higher SOFA scores and more pronounced systemic inflammation than Group 1 patients prior to ECMO initialization. CONCLUSIONS: Extracellular histones are known contributors to cell damage and organ injury. Our study showed that extracellular histones have a predictive value in the assessment of outcome of patients undergoing ECMO therapy and may be helpful for risk stratification in clinical settings.

Increased Concentrations of Extracellular Histones in Patients with Tuberculous Pleural Effusion.

BACKGROUND Extracellular histones have recently been suggested as critical mediators in many inflammatory diseases. However, the role of extracellular histones in tuberculous pleural effusion (TPE) is unclear. The goal of this study was to explore the potential involvement of extracellular histones in patients with TPE. MATERIAL AND METHODS Samples of pleural effusion and peripheral blood were obtained from 58 patients with tuberculosis. Extracellular histones were determined in both TPE and serum samples. Moreover, the biomarkers for cellular damage, inflammatory cell activation, and systemic inflammation including lactate dehydrogenase (LDH), myeloperoxidase (MPO), S100A8/A9, as well as multiple inflammatory cytokines were measured. RESULTS Extracellular histone levels were significantly elevated in TPE (4.762 mg/mL [3.336, 7.307]) and serum samples (1.502 mg/mL [1.084, 2.478]) from tuberculosis patients as compared with the serum (0.585 mg/mL [0.285, 0.949]) from healthy controls. Notably, extracellular histones in TPE were also much higher than in serum of patients (P=0.002). LDH, MPO, and S100A8/A9 levels were all increased in TPE, along with a remarkable elevation of various cytokines. A correlation analysis showed that extracellular histones were positively associated with LDH, MPO, and S100A8/A9, and a panel of inflammatory cytokines in TPE. CONCLUSIONS These results suggest that high concentrations of extracellular histones are markedly present in TPE, which may play an inflammatory role towards the progression of tuberculosis.

Extracellular histones are clinically relevant mediators in the pathogenesis of acute respiratory distress syndrome.

BACKGROUND: Extracellular histones were recently identified as an inflammatory mediator involved in the pathogenesis of various organ injuries. This study aimed to examine extracellular histone levels and their clinical implications in acute respiratory distress syndrome (ARDS) patients and to explore histone-mediated effects through ex-vivo investigations. METHODS: Extracellular histones, cytokine profiles and clinical data from 96 ARDS patients and 30 healthy volunteers were obtained. Human bronchial epithelial cells (BEAS-2B), human pulmonary artery endothelial cells (HPAEC), and human monocytic U937 cells were exposed to bronchoalveolar lavage fluid (BALF) collected from ARDS patients, and cellular damage and cytokine production were assessed. Furthermore, the effect of histone-targeted interventions by heparin or anti-histone antibody was evaluated. RESULTS: Plasma and BALF extracellular histone levels were much higher in ARDS patients than in healthy controls. There was a significant association between extracellular histones and ARDS severity and mortality. In addition, extracellular histones correlated with an evident systemic inflammation detected in ARDS patients. Ex-vivo analysis further showed that ARDS patient's BALF remarkably induced epithelial and endothelial cell damage and stimulated cytokine production in the supernatant of U937 cells. The adverse effects on these cells could be abrogated by heparin or anti-histone antibody. CONCLUSIONS: Extracellular histones in ARDS patients are excessively increased and may contribute to disease aggravation by inducing cellular damage and promoting systemic inflammation. Targeting extracellular histones may provide a promising approach for treating ARDS.

Neutrophils counteract autophagy-mediated anti-inflammatory mechanisms in alveolar macrophage: role in posthemorrhagic shock acute lung inflammation.

Acute lung injury (ALI) is a major component of multiple organ dysfunction syndrome after hemorrhagic shock (HS) resulting from major surgery and trauma. The increased susceptibility in HS patients to the development of ALI suggests not yet fully elucidated mechanisms that enhance proinflammatory responses and/or suppress anti-inflammatory responses in the lung. Alveolar macrophages (AMϕ) are at the center of the pathogenesis of ALI after HS. We have previously reported that HS-activated polymorphonuclear neutrophils (PMNs) interact with macrophages to influence inflammation progress. In this study, we explore a novel function of PMNs regulating AMϕ anti-inflammatory mechanisms involving autophagy. Using a mouse "two-hit" model of HS/resuscitation followed by intratracheal injection of muramyl dipeptide, we demonstrate that HS initiates high mobility group box 1/TLR4 signaling, which upregulates NOD2 expression in AMϕ and sensitizes them to subsequent NOD2 ligand muramyl dipeptide to augment lung inflammation. In addition, upregulated NOD2 signaling induces autophagy in AMϕ, which negatively regulates lung inflammation through feedback suppression of NOD2-RIP2 signaling and inflammasome activation. Importantly, we further demonstrate that HS-activated PMNs that migrate in alveoli counteract the anti-inflammatory effect of autophagy in AMϕ, possibly through NAD(P)H oxidase-mediated signaling to enhance I-κB kinase γ phosphorylation, NF-κB activation, and nucleotide-binding oligomerization domain protein 3 inflammasome activation, and therefore augment post-HS lung inflammation. These findings explore a previously unidentified complexity in the mechanisms of ALI, which involves cell-cell interaction and receptor cross talk.

Extracellular histones play an inflammatory role in acid aspiration-induced acute respiratory distress syndrome.

BACKGROUND: Systemic inflammation is a key feature in acid aspiration-induced acute respiratory distress syndrome (ARDS), but the factors that trigger inflammation are unclear. The authors hypothesize that extracellular histones, a newly identified inflammatory mediator, play important roles in the pathogenesis of ARDS. METHODS: The authors used a hydrochloric acid aspiration-induced ARDS model to investigate whether extracellular histones are pathogenic and whether targeting histones are protective. Exogenous histones and antihistone antibody were administered to mice. Heparin can bind to histones, so the authors studied whether heparin could protect from ARDS using cell and mouse models. Furthermore, the authors analyzed whether extracellular histones are clinically involved in ARDS patients caused by gastric aspiration. RESULTS: Extracellular histones in bronchoalveolar lavage fluid of acid-treated mice were significantly higher (1.832 ± 0.698) at 3 h after injury than in sham-treated group (0.63 ± 0.153; P = 0.0252, n = 5 per group). Elevated histones may originate from damaged lung cells and neutrophil infiltration. Exogenous histones aggravated lung injury, whereas antihistone antibody markedly attenuated the intensity of ARDS. Notably, heparin provided a similar protective effect against ARDS. Analysis of plasma from ARDS patients (n = 21) showed elevated histones were significantly correlated with the degree of ARDS and were higher in nonsurvivors (2.723 ± 0.2933, n = 7) than in survivors (1.725 ± 0.1787, P = 0.006, n = 14). CONCLUSION: Extracellular histones may play a contributory role toward ARDS by promoting tissue damage and systemic inflammation and may become a novel marker reflecting disease activity. Targeting histones by neutralizing antibody or heparin shows potent protective effects, suggesting a potentially therapeutic strategy.

Hemorrhagic shock augments Nlrp3 inflammasome activation in the lung through impaired pyrin induction.

Hemorrhagic shock (HS) promotes the development of systemic inflammatory response syndrome and organ injury by activating and priming the innate immune system for an exaggerated inflammatory response through, as of yet, unclear mechanisms. IL-1ß also plays an important role in the development of post-HS systemic inflammatory response syndrome and active IL-1ß production is tightly controlled by the inflammasome. Pyrin, a protein of 781 aa with pyrin domain at the N-terminal, negatively regulates inflammasome activation through interaction with nucleotide-binding oligomerization domain-like receptor protein (NLRP). Expression of pyrin can be induced by LPS and cytokines, and IL-10 is a known potent inducer of pyrin expression in macrophages. In the current study, we tested the hypothesis that HS downregulates IL-10 and therefore decreases pyrin expression to promote inflammasome activation and subsequent IL-1ß processing and secretion in the lungs. Our results show that LPS, while activating Nlrp3 inflammasome in the lungs, also induced pyrin expression, which in turn suppressed inflammasome activation. More importantly, LPS-mediated upregulation of IL-10 enhanced pyrin expression, which serves, particularly in later phases, as a potent negative-feedback mechanism regulating inflammasome activation. However, HS-mediated suppression of IL-10 expression in alveolar macrophages attenuated the upregulation of pyrin in alveolar macrophages and lung endothelial cells and thereby significantly enhanced inflammasome activation and IL-1ß secretion in the lungs. This study demonstrates a novel mechanism by which HS suppresses negative-feedback regulation of Nlrp3 inflammasome to enhance IL-1ß secretion in response to subsequent LPS challenge and so primes for inflammation.

Intraoperative partial pressure of arterial carbon dioxide levels and adverse outcomes in patients undergoing lung transplantation.

OBJECTIVE: Patients undergoing lung transplantation (LTx) often experience abnormal hypercapnia or hypocapnia. This study aimed to investigate the association between intraoperative PaCO2 and postoperative adverse outcomes in patients undergoing LTx. METHODS: We retrospectively reviewed the medical records of 151 patients undergoing LTx. Patients' demographics, perioperative clinical factors, and pre- and intraoperative PaCO2 data after reperfusion were collected and analyzed. Based on the PaCO2 levels, patients were classified into three groups: hypocapnia (≤35 mmHg), normocapnia (35.1-55 mmHg), and hypercapnia (>55 mmHg). Univariate and multivariable logistic regressions were used to identify independent risk factors for postoperative composite adverse events and in-hospital mortality. RESULTS: Intraoperative hypercapnia occurred in 69 (45.7%) patients, and hypocapnia in 17 (11.2%). Patients with intraoperative PaCO2 of 35.1-45 mmHg showed a lower incidence of composite adverse events (53.3%) and mortality (6.2%) (P < 0.001). There was no significant difference in composite adverse events and mortality among preoperative PaCO2 groups (P > 0.05). Compared with intraoperative PaCO2 at 35.1-45 mmHg, the risk of composite adverse events in hypercapnia group increased: the adjusted OR was 3.07 (95% confidence interval [CI]: 1.36-6.94; P = 0.007). The risk of death was significantly higher in hypocapnia group than normocapnia group, the adjusted OR was 7.69 (95% CI: 1.68-35.24; P = 0.009). Over ascending ranges of PaCO2, PaCO2 at 55.1-65 mmHg had the strongest association with composite adverse events, the adjusted OR was 6.40 (95% CI: 1.18-34.65; P = 0.031). CONCLUSION: These results demonstrate that intraoperative hypercapnia independently predicts postoperative adverse outcomes in patients undergoing LTx. Intraoperative hypocapnia shows predictive value for postoperative in-hospital mortality in LTx.

Cathepsin C from extracellular histone-induced M1 alveolar macrophages promotes NETosis during lung ischemia-reperfusion injury.

Primary graft dysfunction (PGD) is a severe form of acute lung injury resulting from lung ischemia/reperfusion injury (I/R) in lung transplantation (LTx), associated with elevated post-transplant morbidity and mortality rates. Neutrophils infiltrating during reperfusion are identified as pivotal contributors to lung I/R injury by releasing excessive neutrophil extracellular traps (NETs) via NETosis. While alveolar macrophages (AMs) are involved in regulating neutrophil chemotaxis and infiltration, their role in NETosis during lung I/R remains inadequately elucidated. Extracellular histones constitute the main structure of NETs and can activate AMs. In this study, we confirmed the significant involvement of extracellular histone-induced M1 phenotype of AMs (M1-AMs) in driving NETosis during lung I/R. Using secretome analysis, public protein databases, and transwell co-culture models of AMs and neutrophils, we identified Cathepsin C (CTSC) derived from AMs as a major mediator in NETosis. Further elucidating the molecular mechanisms, we found that CTSC induced NETosis through a pathway dependent on NADPH oxidase-mediated production of reactive oxygen species (ROS). CTSC could significantly activate p38 MAPK, resulting in the phosphorylation of the NADPH oxidase subunit p47phox, thereby facilitating the trafficking of cytoplasmic subunits to the cell membrane and activating NADPH oxidase. Moreover, CTSC up-regulated and activated its substrate membrane proteinase 3 (mPR3), resulting in an increased release of NETosis-related inflammatory factors. Inhibiting CTSC revealed great potential in mitigating NETosis-related injury during lung I/R. These findings suggests that CTSC from AMs may be a crucial factor in mediating NETosis during lung I/R, and targeting CTSC inhition may represent a novel intervention for PGD in LTx.

Identification of Neutrophil Extracellular Trap-Related Gene Expression Signatures in Ischemia Reperfusion Injury During Lung Transplantation: A Transcriptome Analysis and Clinical Validation.

Purpose: Ischemia reperfusion injury (IRI) unavoidably occurs during lung transplantation, further contributing to primary graft dysfunction (PGD). Neutrophils are the end effectors of IRI and activated neutrophils release neutrophil extracellular traps (NETs) to further amplify damage. Nevertheless, potential contributions of NETs in IRI remain incompletely understood. This study aimed to explore NET-related gene biomarkers in IRI during lung transplantation. Methods: Differential expression analysis was applied to identify differentially expressed genes (DEGs) for IRI during lung transplantation based on matrix data (GSE145989, 127003) downloaded from GEO database. The CIBERSORT and weighted gene co-expression network analysis (WGCNA) algorithms were utilized to identify key modules associated with neutrophil infiltration. Moreover, the least absolute shrinkage and selection operator regression and random forest were applied to identify potential NET-associated hub genes. Subsequently, the screened hub genes underwent further validation of an external dataset (GSE18995) and nomogram model. Based on clinical peripheral blood samples, immunofluorescence staining and dsDNA quantification were used to assess NET formation, and ELISA was applied to validate the expression of hub genes. Results: Thirty-eight genes resulted from the intersection between 586 DEGs and 75 brown module genes, primarily enriched in leukocyte migration and NETs formation. Subsequently, four candidate hub genes (FCAR, MMP9, PADI4, and S100A12) were screened out via machine learning algorithms. Validation using an external dataset and nomogram model achieved better predictive value. Substantial NETs formation was demonstrated in IRI, with more pronounced NETs observed in patients with PGD ≥ 2. PADI4, S100A12, and MMP9 were all confirmed to be up-regulated after reperfusion through ELISA, with higher levels of S100A12 in PGD ≥ 2 patients compared with non-PGD patients. Conclusion: We identified three potential NET-related biomarkers for IRI that provide new insights into early detection and potential therapeutic targets of IRI and PGD after lung transplantation.

Circulating histones exacerbate inflammation in mice with acute liver failure.

Circulating histones are a newly recognized mediator implicated in various inflammatory diseases. It is likely that the release of histones, from dying hepatocytes or inflammatory leukocytes, into the circulation initiates and amplifies inflammation during the course of acute liver failure (ALF). In this study, we investigated a putative pathogenic role of circulating histones in a murine model of ALF induced by D-galactosamine (GalN) plus lipopolysaccharide (LPS). Hepatic function and histological indexes, myeloperoxidase (MPO) activity, hepatocyte apoptosis and the levels of circulating histone were measured in GalN/LPS-treated mice. GalN/LPS caused severe liver damage and a notable increase in plasma concentration of circulating histones. To further assess the role of circulating histones in our model, we administered exogenous histones and anti-histone H4 antibody. Notably, exogenous histones aggravated GalN/LPS-induced hepatotoxicity, whereas anti-histone antibody significantly protected mice. Circulating histones may serve as both a functional marker of ALF activity and as an inflammatory mediator contributing to the progression of ALF. Blockade of circulating histones shows potent protective effects, suggesting a potential therapeutic strategy for ALF.

Low dose of carbon monoxide intraperitoneal injection provides potent protection against GalN/LPS-induced acute liver injury in mice.

Carbon monoxide (CO) is an important effector-signaling molecule involved in various pathophysiological processes. Here we investigated the protective effects of exogenous CO in a murine model of acute liver damage induced by d-galactosamine (GalN) and lipopolysaccharide (LPS). Exogenous CO gas was administered to mice via intraperitoneal injection (first at a dose of 15 ml kg(-1) and then, 6 h later, 8 ml kg(-1)), which caused a significant elevation of blood carboxyhemoglobin levels of up to 12-14% for more than 12 h. GalN/LPS were given to induce acute liver damage in mice 30 min prior to CO exposure. This showed that GalN/LPS induced severe liver injury in mice, whereas CO injection remarkably improved the survival rate of mice and led to attenuated hepatocellular damage. CO exhibited anti-oxidative capabilities by inhibiting hepatic malondialdehyde contents and restoring superoxide dismutase and glutathione, as well as by reducing inducible NOS/NO production. The anti-apoptotic and anti-inflammatory effects of CO were substantial, characterized by a notable inhibition of hepatocyte apoptosis and a reduction of pro-inflammatory cytokines in mice. Our findings thus supported the hypothesis that exogenous CO provides protective effects against acute liver damage in mice, mainly dependent on its anti-oxidative, anti-inflammatory and anti-apoptotic properties.

Ultrasound-Guided Bilateral Sequential Thoracic Paravertebral Block for Simultaneous Bilateral Uniportal Video-Assisted Thoracoscopic Surgery: Study Protocol for a Randomized Controlled Trial.

Purpose: Simultaneous bilateral pulmonary resection via uniportal video-assisted thoracoscopic surgery (UVATS) was safe and feasible for the treatment of bilateral multiple pulmonary nodules. But, it should be noted that considerable postoperative pain at the bilateral surgical site was a crucial issue. The safety and efficacy of bilateral thoracic paravertebral block (TPVB) have been reported for postoperative analgesia. But, whether bilateral sequential TPVB can be safely and effectively used in simultaneous bilateral UVATS remains unknown. Therefore, this study aimed to determine the analgesic efficacy and safety of bilateral sequential TPVB after simultaneous bilateral UVATS. Study Design and Methods: In this study, 80 participants scheduled for UVATS will be randomly allocated to the bilateral sequential TPVB group (G2) and the control group (G1). The patient of G2 will be performed bilateral TPVB at 2 time-points: before the start of the first side of pulmonary resection and before the start of the contralateral pulmonary resection. G1 will only receive standard analgesia protocol. The primary outcome is the numeric rating scale score during coughing at 24 h postoperatively. The secondary outcomes include the Prince Henry Pain Score scores, sufentanil consumption, postoperative nausea and vomiting, levels of inflammatory factors, and the Quality of Recovery-40 scores at different time points, as well as chronic pain at postoperative day (POD) 90. Discussion: This is the first prospective trial to determine the safety and effectiveness of ultrasound-guided bilateral sequential TPVB for postoperative analgesia following simultaneous bilateral UVATS. This study also intended to evaluate the effect of this intervention on postoperative quality of recovery and inflammation levels. The final results will provide clinical evidence related to bilateral sequential TPVB, and promote the application of that acting as a more appropriate analgesic method for simultaneous bilateral UVATS.

Association of preoperative spirometry tests with postoperative pulmonary complications after mediastinal mass resection: protocol for a retrospective cohort study.

INTRODUCTION: Patients with a mediastinal mass are at risk of pulmonary complications in the perioperative period. Preoperative spirometry tests are recommended in patients scheduled for thoracic surgery. Our objective is to investigate the association between preoperative spirometry results and the incidence of postoperative pulmonary complications in patients following mediastinal mass resection, which may determine the usefulness of spirometry tests in the prediction of the perioperative respiratory risk. METHODS AND ANALYSIS: This protocol describes a retrospective cohort study of patients with mediastinal masses in Shanghai Pulmonary Hospital between 1 September 2021 and 1 September 2022, with a planned sample size of 660 patients. The primary aim of this study is to explore the association between preoperative spirometry results and the occurrence of postoperative pulmonary complications after mediastinal mass resection. Logistic regression analysis will be used to calculate the adjusted incidence rate difference and incidence rate ratios (with 95% CIs). ETHICS AND DISSEMINATION: The study was approved by the ethics committee of Shanghai Pulmonary Hospital (K21-372Y). The results of the study will be submitted to a peer-reviewed biomedical journal for publication and presented at relevant conferences.

Diagnostic and Therapeutic Implications of Ex Vivo Lung Perfusion in Lung Transplantation: Potential Benefits and Inherent Limitations.

Ex vivo lung perfusion (EVLP), a technique in which isolated lungs are continually ventilated and perfused at normothermic temperature, is emerging as a promising platform to optimize donor lung quality and increase the lung graft pool. Over the past few decades, the EVLP technique has become recognized as a significant achievement and gained much attention in the field of lung transplantation. EVLP has been demonstrated to be an effective platform for various targeted therapies to optimize donor lung function before transplantation. Additionally, some physical parameters during EVLP and biological markers in the EVLP perfusate can be used to evaluate graft function before transplantation and predict posttransplant outcomes. However, despite its advantages, the clinical practice of EVLP continuously encounters multiple challenges associated with both intrinsic and extrinsic limitations. It is of utmost importance to address the advantages and disadvantages of EVLP for its broader clinical usage. Here, the pros and cons of EVLP are comprehensively discussed, with a focus on its benefits and potential approaches for overcoming the remaining limitations. Directions for future research to fully explore the clinical potential of EVLP in lung transplantation are also discussed.

Effects of preoperative mildly elevated pulmonary artery systolic pressure on the incidence of perioperative adverse events undergoing thoracoscopic lobectomy: an observational cohort study protocol.

INTRODUCTION: Echocardiography provides a non-invasive estimation of pulmonary artery systolic pressure (PASP) and is the first diagnostic test for pulmonary hypertension. Recent studies have demonstrated that PASP of more than 30 mm Hg related to increased mortality and morbidity. However, perioperative risks and management for patients with mildly elevated PASP are not well established. This study aims to explore the association between mildly elevated PASP and perioperative adverse outcomes. METHODS AND ANALYSIS: This will be a retrospective cohort study conducted at Shanghai Pulmonary Hospital in Shanghai, China. Eligible patients are adults (≥18 years) who performed preoperative echocardiography and followed thoracoscopic lobectomy. Our primary objective is to determine the effect of preoperative mildly elevated PASP on the incidence of hypotension during surgery. Whether mildly elevated PASP is related to other perioperative adverse events (including hypoxaemia, myocardial injury, new-onset atrial fibrillation, postoperative pulmonary complications, 30-day readmission and 30-day mortality) will be also analysed. An estimated 2300 patients will be included. ETHICS AND DISSEMINATION: The study has been approved by the institutional review board of Shanghai Pulmonary Hospital (approval No: 2022LY1143). The research findings intend to be published in peer-reviewed scientific publications. TRIAL REGISTRATION NUMBER: Chinese Clinical Trial Registry (ChiCTR2200066679).

Shock lung is not "wet" but characterized as necroptotic inflammation in a mouse model of hypotension.

OBJECTIVES: Hypotension episodes before or after donor brain death are assumed to trigger hypoxia-reoxygenation, causing diffuse alveolar-capillary damage via necrosis. However, alveolar-capillary membranes have direct access to oxygen in alveoli. We hypothesized hypotension-induced lung injury is not diffuse alveolar-capillary damage but interstitial inflammation resulting from nonhypoxic lung ischemia and systemic responses to hypoxic extrapulmonary ischemia. METHODS: The 4-hour hypotension model was established by subjecting C57BL/6J mice to 4-hour hypotension at 15 ± 5 mm Hg of mean artery pressure and resuscitated with whole shed blood and norepinephrine. Nonhypoxic lung ischemia model was established by 4-hour left pulmonary artery ligation. At 24 hours postprocedure, an arterial blood gas analysis and a gastroduodenal occult blood test were conducted. Lung samples were assessed for histology, cytokine transcripts, regulated cell death, and alveolar-capillary permeability. RESULTS: The 4-hour hypotension model had an intraoperative mortality rate of 17.7% (41/231) and a stress-ulcer bleeding rate of 15.3% (29/190). No signs of alveolar flooding were observed in both models. Four-hour hypotension without stress ulcer showed normal oxygenation and permeability but increased interstitial infiltration, transcription of Tnf and Il1b, phosphorylation of MLKL and RIPK3, and cleaved caspase 3 compared with 4-hour pulmonary artery ligation and naïve control. Animals that developed stress ulcer presented with worse pulmonary infiltration, intracellular edema, and oxygenation but just slightly increased permeability. Immunoblotting showed significant upregulations of protein expression and phosphorylation of MLKL and RIPK3, cleaved Caspase-3, but not its prototype in 4-hour hypotension with stress ulcer. CONCLUSIONS: Hypotensive lung injury is essentially a nonhypoxic ischemia-reperfusion injury enhanced by systemic responses. It is predominated by necroptosis-induced inflammation rather than necrosis-induced diffuse alveolar-capillary damage.