GDF15 ameliorates sepsis-induced lung injury via AMPK-mediated inhibition of glycolysis in alveolar macrophage.

Growth differentiation factor 15 (GDF15) as a stress response cytokine is involved in the development and progression of several diseases associated with metabolic disorders. However, the regulatory role and the underlying mechanisms of GDF15 in sepsis remain poorly defined. Our study analyzed the levels of GDF15 and its correlations with the clinical prognosis of patients with sepsis. In vivo and in vitro models of sepsis were applied to elucidate the role and mechanisms of GDF15 in sepsis-associated lung injury. We observed strong correlations of plasma GDF15 levels with the levels of C-reactive protein (CRP), procalcitonin (PCT), lactate dehydrogenase (LDH), and lactate as well as Sequential Organ Failure Assessment (SOFA) scores in patients with sepsis. In the mouse model of lipopolysaccharide-induced sepsis, recombinant GDF15 inhibited the proinflammatory responses and alleviated lung tissue injury. In addition, GDF15 decreased the levels of cytokines produced by alveolar macrophages (AMs). The anti-inflammatory effect of glycolysis inhibitor 2-DG on AMs during sepsis was mediated by GDF15 via inducing the phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) and the expression of activating transcription factor 4 (ATF4). Furthermore, we explored the mechanism underlying the beneficial effects of GDF15 and found that GDF15 inhibited glycolysis and mitogen-activated protein kinases (MAPK)/nuclear factor-κB (NF-κB) signaling via promoting AMPK phosphorylation. This study demonstrated that GDF15 inhibited glycolysis and NF-κB/MAPKs signaling via activating AMP-activated protein kinase (AMPK), thereby alleviating the inflammatory responses of AMs and sepsis-associated lung injury. Our findings provided new insights into novel therapeutic strategies for treating sepsis.

Development and external validation of a nomogram for the early prediction of acute kidney injury in septic patients: a multicenter retrospective clinical study.

Background and purpose: Acute kidney injury (AKI) is a common serious complication in sepsis patients with a high mortality rate. This study aimed to develop and validate a predictive model for sepsis associated acute kidney injury (SA-AKI). Methods: In our study, we retrospectively constructed a development cohort comprising 733 septic patients admitted to eight Grade-A tertiary hospitals in Shanghai from January 2021 to October 2022. Additionally, we established an external validation cohort consisting of 336 septic patients admitted to our hospital from January 2017 to December 2019. Risk predictors were selected by LASSO regression, and a corresponding nomogram was constructed. We evaluated the model's discrimination, precision and clinical benefit through receiver operating characteristic (ROC) curves, calibration plots, decision curve analysis (DCA) and clinical impact curves (CIC) in both internal and external validation. Results: AKI incidence was 53.2% in the development cohort and 48.2% in the external validation cohort. The model included five independent indicators: chronic kidney disease stages 1 to 3, blood urea nitrogen, procalcitonin, D-dimer and creatine kinase isoenzyme. The AUC of the model in the development and validation cohorts was 0.914 (95% CI, 0.894-0.934) and 0.923 (95% CI, 0.895-0.952), respectively. The calibration plot, DCA, and CIC demonstrated the model's favorable clinical applicability. Conclusion: We developed and validated a robust nomogram model, which might identify patients at risk of SA-AKI and promising for clinical applications.

Early short-term abdominal paracentesis drainage in moderately severe and severe acute pancreatitis with pelvic ascites.

BACKGROUND: We sought to evaluate the effect of early short-term abdominal paracentesis drainage (APD) in moderately severe and severe acute pancreatitis (MSAP/SAP) with pelvic ascites. METHODS: A total of 135 MSAP/SAP patients with early pelvic ascites were divided into the Short-term APD group (57 patients) and the Non-APD group (78 patients). The effects, complications, and prognosis of short-term APD patients were evaluated. RESULTS: The baseline characteristics in the two groups were similar. The target days of intra-abdominal hypertension relief, half-dose enteral nutrition, duration of mechanical ventilation, length of intensive care unit stay (in days) and total hospitalization (also in days) were all lower in the Short-term APD group than in the Non-APD group (P = 0.002, 0.009, 0.004, 0.006 and 0.019), while the white blood cell count and serum C-reaction protein level decreased significantly more quickly (P < 0.01 and P < 0.05), and the prevalence of intra-abdominal infection was also significantly lower (P = 0.014) in the former than the latter. No complications occurred in early APD patients, and the microbial cultures of pelvic ascites were all negative. In addition, patients with early APD presented fewer cases of residual wall-off necrosis or fluid collection (P = 0.008) at discharge and had a lower incidence of rehospitalization and percutaneous catheter drainage and/or necrosectomy (P = 0.017 and 0.009). CONCLUSIONS: For MSAP/SAP patients with pelvic ascites, the early short-term APD is feasible and safe to perform, and it can decrease clinical symptoms, reduce intra-abdominal infection and shorten the hospital stay. It may also reduce the incidence of rehospitalization and surgical intervention.

Immune effects of PI3K/Akt/HIF-1α-regulated glycolysis in polymorphonuclear neutrophils during sepsis.

BACKGROUND: Effective removal of pathogenic bacteria is key to improving the prognosis of sepsis. Polymorphonuclear neutrophils (PMNs) are the most important components of innate cellular immunity and play vital roles in clearing pathogenic bacteria. However, the metabolic characteristics and immunomodulatory pathways of PMNs during sepsis have not been investigated. In the present study, we explored the immune metabolism characteristics of PMNs and the mechanism by which neutrophilic glycolysis is regulated during sepsis. METHODS: Metabolomics analysis was performed on PMNs isolated from 14 septic patients, 26 patients with acute appendicitis, and 19 healthy volunteers. Transcriptome analysis was performed on the PMNs isolated from the healthy volunteers and the patients with sepsis to assess glycolysis and investigate its mechanism. Lipopolysaccharide (LPS) was used to stimulate the neutrophils isolated from the healthy volunteers at different time intervals to build an LPS-tolerant model. Chemotaxis, phagocytosis, lactate production, oxygen consumption rate (OCR), and extracellular acidification rate (ECAR) were evaluated. RESULTS: Transcriptomics showed significant changes in glycolysis and the mTOR/HIF-1α signaling pathway during sepsis. Metabolomics revealed that the Warburg effect was significantly altered in the patients with sepsis. We discovered that glycolysis regulated PMNs' chemotaxis and phagocytosis functions during sepsis. Lactate dehydrogenase A (LDHA) downregulation was a key factor in the inhibition of glycolysis in PMNs. This study confirmed that the PI3K/Akt-HIF-1α pathway was involved in the LDHA expression level and also influenced PMNs' chemotaxis and phagocytosis functions. CONCLUSIONS: The inhibition of glycolysis contributed to neutrophil immunosuppression during sepsis and might be controlled by PI3K/Akt-HIF-1α pathway-mediated LDHA downregulation. Our study provides a scientific theoretical basis for the management and treatment of patients with sepsis and promotes to identify therapeutic target for the improvement of immune function in sepsis.

Clinical validation of a multiplex droplet digital PCR for diagnosing suspected bloodstream infections in ICU practice: a promising diagnostic tool.

BACKGROUND: Droplet digital PCR (ddPCR) has emerged as a promising tool of pathogen detection in bloodstream infections (BSIs) in critical care medicine. However, different ddPCR platforms have variable sensitivity and specificity for diverse microorganisms at various infection sites. There is still a lack of prospective clinical studies aimed at validating and interpreting the discrepant ddPCR results for diagnosing BSI in intensive care unit (ICU) practice. METHODS: A prospective diagnostic study of multiplex ddPCR panels was conducted in a general ICU from May 21, 2021, to December 22, 2021. Paired blood cultures (BCs) and ddPCRs (2.5 h) were obtained synchronously to detect the 12 most common BSI pathogens and three antimicrobial resistance (AMR) genes. Firstly, ddPCR performance was compared to definite BSI. Secondly, clinical validation of ddPCR was compared to composite clinical diagnosis. Sensitivity, specificity, and positive and negative predictive values were calculated. Thirdly, the positive rate of AMR genes and related analysis was presented. RESULTS: A total of 438 episodes of suspected BSIs occurring in 150 critical patients were enrolled. BC and ddPCR were positive for targeted bacteria in 40 (9.1%) and 180 (41.1%) cases, respectively. There were 280 concordant and 158 discordant. In comparison with BCs, the sensitivity of ddPCR ranged from 58.8 to 86.7% with an aggregate of 72.5% in different species, with corresponding specificity ranging from 73.5 to 92.2% with an aggregate of 63.1%. Furthermore, the rate of ddPCR+/BC- results was 33.6% (147/438) with 87.1% (128 of 147) cases was associated with probable (n = 108) or possible (n = 20) BSIs. When clinically diagnosed BSI was used as true positive, the final sensitivity and specificity of ddPCR increased to 84.9% and 92.5%, respectively. In addition, 40 blaKPC, 3blaNDM, and 38 mecA genes were detected, among which 90.5% were definitely positive for blaKPC. Further, 65.8% specimens were predicted to be mecA-positive in Staphylococcus sp. according to all microbiological analysis. CONCLUSIONS: The multiplexed ddPCR is a flexible and universal platform, which can be used as an add-on complementary to conventional BC. When combined with clinical infection evidence, ddPCR shows potential advantages for rapidly diagnosing suspected BSIs and AMR genes in ICU practice.

Nomogram for prediction of severe community-acquired pneumonia development in diabetic patients: a multicenter study.

BACKGROUND: Diabetic patients with community-acquired pneumonia (CAP) have an increased risk of progressing to severe CAP. It is essential to develop predictive tools at the onset of the disease for early identification and intervention. This study aimed to develop and validate a clinical feature-based nomogram to identify diabetic patients with CAP at risk of developing severe CAP. METHOD: A retrospective cohort study was conducted between January 2019 to December 2020. 1026 patients with CAP admitted in 48 hospitals in Shanghai were enrolled. All included patients were randomly divided into the training and validation samples with a ratio of 7:3. The nomogram for the prediction of severe CAP development was established based on the results of the multivariate logistic regression analysis and other predictors with clinical relevance. The nomogram was then assessed using receiver operating characteristic curves (ROC), calibration curve, and decision curve analysis (DCA). RESULTS: Multivariate analysis showed that chronic kidney dysfunction, malignant tumor, abnormal neutrophil count, abnormal lymphocyte count, decreased serum albumin level, and increased HbA1c level at admission was independently associated with progression to severe CAP in diabetic patients. A nomogram was established based on these above risk factors and other predictors with clinical relevance. The area under the curve (AUC) of the nomogram was 0.87 (95% CI 0.83-0.90) in the training set and 0.84 (95% CI 0.78-0.90). The calibration curve showed excellent agreement between the predicted possibility by the nomogram and the actual observation. The decision curve analysis indicated that the nomogram was applicable with a wide range of threshold probabilities due to the net benefit. CONCLUSION: Our nomogram can be applied to estimate early the probabilities of severe CAP development in diabetic patients with CAP, which has good prediction accuracy and discrimination abilities. Since included biomarkers are common, our findings may be performed well in clinical practice and improve the early management of diabetic patients with CAP.

Transferability and interpretability of the sepsis prediction models in the intensive care unit.

BACKGROUND: We aimed to develop an early warning system for real-time sepsis prediction in the ICU by machine learning methods, with tools for interpretative analysis of the predictions. In particular, we focus on the deployment of the system in a target medical center with small historical samples. METHODS: Light Gradient Boosting Machine (LightGBM) and multilayer perceptron (MLP) were trained on Medical Information Mart for Intensive Care (MIMIC-III) dataset and then finetuned on the private Historical Database of local Ruijin Hospital (HDRJH) using transfer learning technique. The Shapley Additive Explanations (SHAP) analysis was employed to characterize the feature importance in the prediction inference. Ultimately, the performance of the sepsis prediction system was further evaluated in the real-world study in the ICU of the target Ruijin Hospital. RESULTS: The datasets comprised 6891 patients from MIMIC-III, 453 from HDRJH, and 67 from Ruijin real-world data. The area under the receiver operating characteristic curves (AUCs) for LightGBM and MLP models derived from MIMIC-III were 0.98 - 0.98 and 0.95 - 0.96 respectively on MIMIC-III dataset, and, in comparison, 0.82 - 0.86 and 0.84 - 0.87 respectively on HDRJH, from 1 to 5 h preceding. After transfer learning and ensemble learning, the AUCs of the final ensemble model were enhanced to 0.94 - 0.94 on HDRJH and to 0.86 - 0.9 in the real-world study in the ICU of the target Ruijin Hospital. In addition, the SHAP analysis illustrated the importance of age, antibiotics, net balance, and ventilation for sepsis prediction, making the model interpretable. CONCLUSIONS: Our machine learning model allows accurate real-time prediction of sepsis within 5-h preceding. Transfer learning can effectively improve the feasibility to deploy the prediction model in the target cohort, and ameliorate the model performance for external validation. SHAP analysis indicates that the role of antibiotic usage and fluid management needs further investigation. We argue that our system and methodology have the potential to improve ICU management by helping medical practitioners identify at-sepsis-risk patients and prepare for timely diagnosis and intervention. TRIAL REGISTRATION: NCT05088850 (retrospectively registered).

Serum-soluble PD-L1 may be a potential diagnostic biomarker in sepsis.

To investigate whether serum-soluble PD-L1 (sPD-L1) is a potential biomarker for identifying sepsis. This study enrolled 64 septic patients, 29 patients with acute appendicitis, 33 patients with acute pancreatitis and 30 healthy volunteers. Sepsis was defined according to the Sepsis 3.0 criteria.[1] The associated clinical parameters were recorded, blood samples were collected on the first day of diagnosis, and serum sPD-L1 levels were measured using enzyme-linked immunosorbent assays. Compared with the control group, a significant increase in sPD-L1 levels was observed in patients with sepsis (n = 64). Increased sPD-L1 expression correlated strongly with increased clinical inflammatory values (CRP, PCT and WBC) and decreased immunological functional parameters (CD3+ , CD4+ and CD8+ cell counts). The area under the ROC curve (AUC) for sPD-L1 in combination with the sequential organ failure assessment (SOFA) score was superior to the AUC for either sPD-L1 or SOFA score in regard to the diagnosis of sepsis. sPD-L1 may represent a valuable biomarker for the diagnosis of sepsis.

Upregulation of endothelial cell-derived exosomal microRNA-125b-5p protects from sepsis-induced acute lung injury by inhibiting topoisomerase II alpha.

OBJECTIVE: Emerging evidence has revealed that exosomal microRNAs (miRNAs) are implicated in human diseases. However, role of exosomal miR-125b-5p in sepsis-induced acute lung injury (ALI) remains further explored. We focused on the effect of exosomal miR-125b-5p on ALI progression via targeting topoisomerase II alpha (TOP2A). METHODS: The ALI mouse models were established by cecal ligation and perforation, which were then treated with miR-125b-5p agomir or overexpressed TOP2A. Next, the pathological structure of ALI mouse lung tissues were observed, miR-125b-5p, TOP2A and vascular endothelial growth factor (VEGF) expression was determined, and the lung water content, inflammatory response, protein content in bronchoalveolar lavage fluid (BALF) and cell apoptosis in ALI mouse lung tissues were assessed. Exosomes were extracted from endothelial cells (ECs) and identified, which were then injected into the modeled mice to observe their roles in ALI. The targeting relationship between miR-125b-5p and TOP2A was confirmed. RESULTS: MiR-125b-5p was downregulated while TOP2A was upregulated in ALI mice. MiR-125b-5p elevation or ECs-derived exosomes promoted VEGF expression, improved pathological changes and restrained lung water content, inflammatory response, protein content in BALF and cell apoptosis in lung tissues ALI mice. TOP2A overexpression reversed the repressive role of miR-125b-5p upregulation in ALI, while downregulated miR-125b-5p abrogated the effect of ECs-derived exosomes on ALI. TOP2A was confirmed as a direct target gene of miR-125b-5p. CONCLUSION: Our study indicates that ECs-derived exosomes overexpressed miR-125b-5p to protect from sepsis-induced ALI by inhibiting TOP2A, which may contribute to ALI therapeutic strategies.

Increased mortality of acute respiratory distress syndrome was associated with high levels of plasma phenylalanine.

BACKGROUND: There is a dearth of drug therapies available for the treatment of acute respiratory distress syndrome (ARDS). Certain metabolites play a key role in ARDS and could serve as potential targets for developing therapies against this respiratory disorder. The present study was designed to determine such "functional metabolites" in ARDS using metabolomics and in vivo experiments in a mouse model. METHODS: Metabolomic profiles of blood plasma from 42 ARDS patients and 28 healthy controls were captured using Ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) assay. Univariate and multivariate statistical analysis were performed on metabolomic profiles from blood plasma of ARDS patients and healthy controls to screen for "functional metabolites", which were determined by variable importance in projection (VIP) scores and P value. Pathway analysis of all the metabolites was performed. The mouse model of ARDS was established to investigate the role of "functional metabolites" in the lung injury and mortality caused by the respiratory disorder. RESULTS: The metabolomic profiles of patients with ARDS were significantly different from healthy controls, difference was also observed between metabolomic profiles of the non-survivors and the survivors among the ARDS patient pool. Levels of Phenylalanine, D-Phenylalanine and Phenylacetylglutamine were significantly increased in non-survivors compared to the survivors of ARDS. Phenylalanine metabolism was the most notably altered pathway between the non-survivors and survivors of ARDS patients. In vivo animal experiments demonstrated that high levels of Phenylalanine might be associated with the severer lung injury and increased mortality of ARDS. CONCLUSION: Increased mortality of acute respiratory distress syndrome was associated with high levels of plasma Phenylalanine. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800015930. Registered 29 April 2018, http://www.chictr.org.cn/edit.aspx?pid=25609&htm=4.

Plasma PTX3, MCP1 and Ang2 are early biomarkers to evaluate the severity of sepsis and septic shock.

Sepsis is associated with significant mortality. Early diagnosis and prognosis of patients with sepsis is still a difficult clinical challenge. In this study, the ability of plasma PTX3 (pentraxin 3), MCP1 (monocyte chemoattractant protein 1) and Ang (angiopoietin)1/2 was investigated to evaluate the severity of sepsis. Blood samples were obtained from 43 patients with sepsis. A total of 33 post-surgery patients with infections and 25 healthy individuals served as controls. The results showed that plasma PTX3, MCP1 and Ang2 significantly increased in patients on the first day of septic shock onset, while sepsis patients had significantly higher Ang2 level, compared with controls. Furthermore, PTX3, MCP1 and Ang2 had high AUROC values in patients with septic shock on the first day of sepsis onset. The findings suggest that PTX3, MCP1 and Ang2 maybe early predictors to evaluate the severity of sepsis and septic shock with the latest Sepsis 3.0 definitions.

Lower respiratory tract microbial composition was diversified in Pseudomonas aeruginosa ventilator-associated pneumonia patients.

BACKGROUND: Probiotics could prevent Pseudomonas aeruginosa colonization in lower respiratory tract (LRT) and reduced P. aeruginosa ventilator-associated pneumonia (VAP) rate. Recent studies also suggested that probiotics could improve lung inflammation in mice infected with P. aeruginosa. It seems that microbiota regulation may be a potential therapy for P. aeruginosa VAP patients. However, we know less about the LRT microbial composition and its correlation with prognosis in P. aeruginosa VAP patients. This study aimed to characterize LRT microbiota in P. aeruginosa VAP patients and explore the relationship between microbiota and patient prognosis. METHODS: Deep endotracheal secretions were sampled from subjects via intubation. Communities were identified by 16S ribosomal RNA gene sequencing. The relationship between microbiota and the prognosis of P. aeruginosa VAP patients were evaluated. Clinical pulmonary infection score and the survival of intensive care unit were both the indicators of patient prognosis. RESULTS: In this study, the LRT microbial composition of P. aeruginosa VAP patients was significantly different from non-infected intubation patients, and showed significant individual differences, forming two clusters. According to the predominant phylum of each cluster, these two clusters were named Pro cluster and Fir-Bac cluster respectively. Patients from Pro cluster were dominated by Proteobacteria (adj.P < 0.001), while those from Fir-Bac cluster were dominated by Firmicutes, and Bacteroidetes (both adj.P < 0.001). These two varied clusters (Pro and Fir-Bac cluster) were associated with the patients' primary disease (χ2-test, P < 0.0001). The primary disease of the Pro cluster mainly included gastrointestinal disease (63%), and the Fir-Bac cluster was predominantly respiratory disease (89%). During the two-week dynamic observation period, despite the use of antibiotics, the dominant genera and Shannon diversity of the LRT microbiota did not change significantly in patients with P. aeruginosa VAP. In prognostic analysis, we found a significant negative correlation between Lactobacillus and clinical pulmonary infection score on the day of diagnosis (P = 0.014); but we found no significant difference of microbial composition between survivors and non-survivors. CONCLUSIONS: LRT microbial composition was diversified among P. aeruginosa VAP patients, forming two clusters which were associated with the primary diseases of the patients.

Monocyte programmed death ligand-1 expression is an early marker for predicting infectious complications in acute pancreatitis.

BACKGROUND: Acute pancreatitis (AP) is a life-threatening disease that requires early identification of patients at risk of developing infectious complications. Immunosuppression is an initial event that is key to AP pathogenesis. The programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) system is reported to mediate evasion of host immune surveillance in many diseases; however, the relationship between PD-1/PD-L1 expression and these parameters or infectious complications in AP has not been elucidated. This study was conducted to determine whether PD-1 and PD-L1 are upregulated and to reveal the relationship between PD-1/PD-L1 expression and the development of infectious complications in AP. METHODS: Sixty-three patients with AP and 32 sex- and age-matched healthy control subjects were prospectively enrolled. On days 1 and 3 after the onset of AP, we measured PD-1 expression in peripheral CD4+ T cells and PD-L1 and human leukocyte antigen-DR (HLA-DR) expression in CD14+ monocytes using flow cytometry. Plasma interleukin (IL)-10 levels were measured by enzyme-linked immunosorbent assay. RESULTS: Compared with healthy volunteers, the percentages of PD-1-expressing CD4+ lymphocytes and PD-L1-expressing CD14+ monocytes were increased in patients with AP on days 1 and 3 after onset, especially those with infectious complications. Moreover, increased PD-1/PD-L1 expression was associated with increased occurrence of infectious complications, decreased circulating lymphocytes, and increased plasma IL-10 concentration. Multivariate regression analysis indicated that the increased percentage of PD-L1-expressing CD14+ monocytes was an independent risk factor for infectious complications in AP. Area under the ROC curve analysis showed the combination of Acute Physiology and Chronic Health Evaluation II score and PD-L1 and HLA-DR expression in CD14+ monocytes had high accuracy in predicting infectious complications in patients with AP. CONCLUSIONS: The PD-1/PD-L1 system plays an essential role in the early immunosuppression of AP. PD-L1 expression in CD14+ monocytes may be a new marker for predicting risk of infectious complications in patients with AP.

Clinical findings in 111 cases of influenza A (H7N9) virus infection.

BACKGROUND: During the spring of 2013, a novel avian-origin influenza A (H7N9) virus emerged and spread among humans in China. Data were lacking on the clinical characteristics of the infections caused by this virus. METHODS: Using medical charts, we collected data on 111 patients with laboratory-confirmed avian-origin influenza A (H7N9) infection through May 10, 2013. RESULTS: Of the 111 patients we studied, 76.6% were admitted to an intensive care unit (ICU), and 27.0% died. The median age was 61 years, and 42.3% were 65 years of age or older; 31.5% were female. A total of 61.3% of the patients had at least one underlying medical condition. Fever and cough were the most common presenting symptoms. On admission, 108 patients (97.3%) had findings consistent with pneumonia. Bilateral ground-glass opacities and consolidation were the typical radiologic findings. Lymphocytopenia was observed in 88.3% of patients, and thrombocytopenia in 73.0%. Treatment with antiviral drugs was initiated in 108 patients (97.3%) at a median of 7 days after the onset of illness. The median times from the onset of illness and from the initiation of antiviral therapy to a negative viral test result on real-time reverse-transcriptase-polymerase-chain-reaction assay were 11 days (interquartile range, 9 to 16) and 6 days (interquartile range, 4 to 7), respectively. Multivariate analysis revealed that the presence of a coexisting medical condition was the only independent risk factor for the acute respiratory distress syndrome (ARDS) (odds ratio, 3.42; 95% confidence interval, 1.21 to 9.70; P=0.02). CONCLUSIONS: During the evaluation period, the novel H7N9 virus caused severe illness, including pneumonia and ARDS, with high rates of ICU admission and death. (Funded by the National Natural Science Foundation of China and others.).

The revised Atlanta criteria 2012 altered the classification, severity assessment and management of acute pancreatitis.

BACKGROUND: The Atlanta criteria for acute pancreatitis (AP) has been revised recently. This study was to evaluate its practical value in classification of AP, the severity assessment and management. METHODS: The clinical features, severity classification, outcome and risk factors for mortality of 3212 AP patients who had been admitted in Ruijin Hospital from 2004 to 2011 were analyzed based on the revised Atlanta criteria (RAC) and the original Atlanta criteria (OAC). RESULTS: Compared to the OAC group, the incidence of severe acute pancreatitis (SAP) was decreased by approximately one half (13.9% vs 28.2%) in the RAC group. The RAC presented a lower sensitivity but higher specificity, and its predictive value for severity and poor outcome was higher than those of the OAC. The proportion of SAP diagnosis and ICU admission in the early phase in the RAC group was significantly lower than that in the OAC group (P<0.05). Based on the RAC, the risk factors for death among SAP patients were older age, high CT severity index (CTSI), renal failure, cardiovascular failure, acute necrotic collection and walled-off necrosis. Compared to the OAC, the acute physiology and chronic health evaluation II (APACHE II) score, Ranson score, idiopathic etiology, respiratory failure and laparotomy debridement were not risk factors of death in contrast to walled-off necrosis. Interestingly, hypertriglyceridemia-related SAP had good outcomes in both groups. CONCLUSIONS: The RAC showed a higher predictive value for severity and poorer outcome than the OAC. However, the RAC resulted in fewer ICU admissions in the early phase due to its lower sensitivity for diagnosis of SAP. Among SAP cases, older age, high CTSI, renal and cardiovascular failure, complications of acute necrotic collection and walled-off necrosis were independent risk factors for mortality.

Sox9 activation is essential for the recovery of lung function after acute lung injury.

BACKGROUND/AIMS: Acute lung injury (ALI) often predisposes acute respiratory distress syndrome (ARDS) in humans, and is featured with neutrophilic alveolitis, injury of the alveolar epithelium and endothelium, hyaline membrane formation, and microvascular thrombi. Although the pathogenesis of ALI is relatively well studied, the knowledge on the molecular regulation of the post-ALI lung recovery are poorly understood. METHODS: Here, we used a widely applied bleomycin-induced ALI model to study the molecular mechanisms that underlie the post-ALI lung recovery in mice. We analyzed Sox9 expression in mouse lung by RT-qPCR, Western blot and immunohistochemistry. We analyzed miR-101 levels in mouse lung by RT-qPCR. We inhibited Sox9 in mouse lung by expressing either shRNA for Sox9 or miR-101, and analyzed the effects of Sox9 suppression on lung recovery. RESULTS: We detected a significant increase in Sox9 protein but not mRNA, and a signifcant decrease in miR-101 levels in the mouse lung after ALI. MiR-101 was found to target 3'-UTR of Sox9 mRNA to inhibit its expression. Sox9 inhibition by either shRNA for Sox9 or by miR-101 further impaired the functional recovery of the lung after ALI. CONCLUSION: Our data suggest that Sox9 activation is essential for the recovery of lung function after ALI, which highlights a previously unappreciated mechanism that controls the post-ALI lung recovery.

Notch Signaling Pathway Was Involved in Regulating Programmed Cell Death 1 Expression during Sepsis-Induced Immunosuppression.

Programmed cell death 1 (PD-1) plays an important pathologic role in sepsis-induced immunosuppression. However, whether PD-1 overexpression occurs early during septic shock is unknown and its regulation mechanism is also unknown. Our study investigated the expressions of PD-1/programmed death-ligand 1 (PD-L1) on immune cells in peripheral blood from the early-stage septic shock patients. We found that both PD-1 and PD-L1 showed increased expressions on the CD4(+) T cells and monocytes. It indicated that PD-1 expression might be an early biomarker to assess illness severity and predict the prognosis of septic shock. Then, we further investigated the mechanism underlying the regulation of PD-1 expression. Our data showed that Notch signaling pathway was activated in both septic shock patients and lipopolysaccharide- (LPS-) tolerant THP1 cells and both interleukin-10 (IL-10) and PD-1 were increased in the THP1 cells. Inhibition of Notch signaling by N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenyl glycinet-butyl ester (DAPT) induced significantly decreased expressions of PD-1 and IL-10 in the LPS-tolerant cell model. Our work suggested that Notch signaling pathway was involved in the regulation of PD-1 expression.

RES-Xre toxin-antitoxin locus knaAT maintains the stability of the virulence plasmid in Klebsiella pneumoniae.

Hypervirulent Klebsiella pneumoniae isolates have been increasingly reported worldwide, especially hypervirulent drug-resistant variants owing to the acquisition of a mobilizable virulence plasmid by a carbapenem-resistant strain. This pLVPK-like mobilizable plasmid encodes various virulence factors; however, information about its genetic stability is lacking. This study aimed to investigate the type II toxin-antitoxin (TA) modules that facilitate the virulence plasmid to remain stable in K. pneumoniae. More than 3,000 TA loci in 2,000 K. pneumoniae plasmids were examined for their relationship with plasmid cargo genes. TA loci from the RES-Xre family were highly correlated with virulence plasmids of hypervirulent K. pneumoniae. Overexpression of the RES toxin KnaT, encoded by the virulence plasmid-carrying RES-Xre locus knaAT, halts the cell growth of K. pneumoniae and E. coli, whereas co-expression of the cognate Xre antitoxin KnaA neutralizes the toxicity of KnaT. knaA and knaT were co-transcribed, representing the characteristics of a type II TA module. The knaAT deletion mutation gradually lost its virulence plasmid in K. pneumoniae, whereas the stability of the plasmid in E. coli was enhanced by adding knaAT, which revealed that the knaAT operon maintained the genetic stability of the large virulence plasmid in K. pneumoniae. String tests and mouse lethality assays subsequently confirmed that a loss of the virulence plasmid resulted in reduced pathogenicity of K. pneumoniae. These findings provide important insights into the role of the RES-Xre TA pair in stabilizing virulence plasmids and disseminating virulence genes in K. pneumoniae.

High-performance lung-targeted bio-responsive platform for severe colistin-resistant bacterial pneumonia therapy.

Polymyxins are the last line of defense against multidrug-resistant (MDR) Gram-negative bacterial infections. However, this last resort has been threatened by the emergence of superbugs carrying the mobile colistin resistance gene-1 (mcr-1). Given the high concentration of matrix metalloproteinase 3 (MMP-3) in bacterial pneumonia, limited plasma accumulation of colistin (CST) in the lung, and potential toxicity of ionic silver (Ag+), we designed a feasible clinical transformation platform, an MMP-3 high-performance lung-targeted bio-responsive delivery system, which we named "CST&Ag@CNMS". This system exhibited excellent lung-targeting ability (>80% in lungs), MMP-3 bio-responsive release property (95% release on demand), and synergistic bactericidal activity in vitro (2-4-fold minimum inhibitory concentration reduction). In the mcr-1+ CST-resistant murine pneumonia model, treatment with CST&Ag@CNMS improved survival rates (70% vs. 20%), reduced bacteria burden (2-3 log colony-forming unit [CFU]/g tissue), and considerably mitigated inflammatory response. In this study, CST&Ag@CNMS performed better than the combination of free CST and AgNO3. We also demonstrated the superior biosafety and biodegradability of CST&Ag@CNMS both in vitro and in vivo. These findings indicate the clinical translational potential of CST&Ag@CNMS for the treatment of lung infections caused by CST-resistant bacteria carrying mcr-1.

Septic macrophages induce T cells immunosuppression in a cell-cell contact manner with the involvement of CR3.

Background: In addition to excessive inflammation, immunosuppression has been recognized as a contributing factor to poor prognosis of sepsis. Although it has been reported that T cells can become functionally impaired during sepsis, the underlying mechanisms responsible for this phenomenon remain unclear. This study aims to elucidate the mechanisms by which macrophages induce immunosuppression in T cells. Methods: In an in vivo setting, C57BL-6J mice were subjected to cecal ligation and puncture (CLP) with or without depletion of macrophages, and the functions of T cells were assessed. In vitro experiments involved direct co-culture or separate culture of T cells and septic macrophages using a transwell system, followed by analysis of T cell immunity. Additionally, a siRNA targeting CD18 on macrophages was utilized to investigate the role of complement receptor 3 (CR3). Results: Both macrophages and T cells exhibited immunosuppression during sepsis. In the in vivo experiments, the absence of macrophages partially alleviated T cell immunosuppression, as evidenced by restored vitality, increased production of TNF-α and IFN-γ, elevated CD8+ T cell levels, and decreased CD25+ T cell levels. In the in vitro experiments, direct co-culture of T cells with septic macrophages resulted in diminished T cell immunity, which was improved when T cells and macrophages were separated by a chamber wall. The expression of CR3 (CD11b/CD18) was upregulated on septic macrophages, and silencing of CD18 led to decreased TNF-α production by T cells, reduced CD4+ T cell numbers, and increased CD25+ T cell numbers. Conclusion: In sepsis, macrophages induce immunosuppression in T cells through direct cell-cell contact, with the involvement of CR3.