Assessment of clinical sepsis-associated biomarkers in a septic mouse model

Protective effects of nordalbergin against LPS-induced endotoxemia through inhibiting MAPK/NF-κB signaling pathway, NLRP3 inflammasome activation, and ROS production

OBJECTIVE

Nordalbergin is a coumarin extracted from Dalbergia sissoo DC. To date, the biological effects of nordalbergin have not been well investigated. To investigate the anti-inflammatory responses and the anti-oxidant abilities of nordalbergin using lipopolysaccharide (LPS)-activated macrophages and LPS-induced sepsis mouse model.

MATERIALS AND METHODS

Production of nitrite oxide (NO), prostaglandin E2 (PGE2), pro-inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β), reactive oxygen species (ROS), tissue damage and serum inflammatory markers, and the activation of the NLRP3 inflammasome were examined.

RESULTS

Our results indicated that nordalbergin reduced the production of NO and pro-inflammatory cytokines in vitro and ex vivo. Nordalbergin also suppressed iNOS and cyclooxygenase-2 expressions, decreased NF-κB activity, and attenuated MAPKs signaling pathway activation by decreasing JNK and p38 phosphorylation by LPS-activated J774A.1 macrophages. Notably, nordalbergin diminished NLRP3 inflammasome activation via repressing the maturation of IL-1β and caspase-1 and suppressing ROS production by LPS/ATP- and LPS/nigericin-activated J774A.1 macrophages. Furthermore, nordalbergin exhibited protective effects against the infiltration of inflammatory cells and also inhibited the levels of organ damage markers (AST, ALT, BUN) by LPS-challenged mice.

CONCLUSION

Nordalbergin possesses anti-inflammatory effects in macrophage-mediated innate immune responses, alleviates ROS production, decreases NLRP3 activation, and exhibits protective effects against LPS-induced tissue damage in mice.

An early sepsis prediction model utilizing machine learning and unbalanced data processing in a clinical context

Background

Early and accurate diagnoses of sepsis patients are essential to reduce the mortality. However, the sepsis is still diagnosed in a traditional way in China despite the increasing number of related studies, which may to some extent lead to delays in the treatment.

Methods

The study included 2,385 patients, including 364 with sepsis, collected from the First Affiliated Hospital of Anhui Medical University and partner hospitals from April to July 2022. External validation was conducted using the MIMIC-III database (over 60,000 patients from 2001 to 2012) and the eICU Collaborative Research Database (139,000 patients from 2014 to 2015). Multiple algorithm models, along with the SHapley Additive exPlanations (SHAP) analysis, are applied to explore the main risk factors for the accurate prediction of the sepsis. Multiple Imputations for filling missing data and the Synthetic Minority Oversampling (SMOTE) balancing method for balancing data are used for the data processing.

Result

Eighteen diagnostic features are used in the predictive model for early sepsis. The Random Forest model has the best performance among all the models, with an Area Under the Curve (AUC) of 87% and an F1-score (F1) of 77%. Moreover, the interpretation from the SHAP analysis is generally consistent with the current clinical situation.

Conclusion

The study revealed the relationship between these 18 clinical features and diagnostic outcomes. The results indicate that patients with laboratory values of Systolic Blood Pressure, Albumin, and Heart Rate exceeding certain thresholds are at a high likelihood of developing sepsis.

Immunomodulatory Effects and Protection in Sepsis by the Antibiotic Moxifloxacin

Sepsis is a leading cause of death in Intensive Care Units. Despite its prevalence, sepsis remains insufficiently understood, with no substantial qualitative improvements in its treatment in the past decades. Immunomodulatory agents may hold promise, given the significance of TNF-α and IL-1β as sepsis mediators. This study examines the immunomodulatory effects of moxifloxacin, a fluoroquinolone utilized in clinical practice. THP1 cells were treated in vitro with either PBS or moxifloxacin and subsequently challenged with lipopolysaccharide (LPS) or E. coli. C57BL/6 mice received intraperitoneal injections of LPS or underwent cecal ligation and puncture (CLP), followed by treatment with PBS, moxifloxacin, meropenem or epirubicin. Atm-/- mice underwent CLP and were treated with either PBS or moxifloxacin. Cytokine and organ lesion markers were quantified via ELISA, colony-forming units were assessed from mouse blood samples, and DNA damage was evaluated using a comet assay. Moxifloxacin inhibits the secretion of TNF-α and IL-1β in THP1 cells stimulated with LPS or E. coli. Intraperitoneal administration of moxifloxacin significantly increased the survival rate of mice with severe sepsis by 80% (p < 0.001), significantly reducing the plasma levels of cytokines and organ lesion markers. Notably, moxifloxacin exhibited no DNA damage in the comet assay, and Atm-/- mice were similarly protected following CLP, boasting an overall survival rate of 60% compared to their PBS-treated counterparts (p = 0.003). Moxifloxacin is an immunomodulatory agent, reducing TNF-α and IL-1β levels in immune cells stimulated with LPS and E. coli. Furthermore, moxifloxacin is also protective in an animal model of sepsis, leading to a significant reduction in cytokines and organ lesion markers. These effects appear unrelated to its antimicrobial activity or induction of DNA damage.

What we know about alterations in immune cells during sepsis in veterinary animals?

Sepsis is still one of the most common causes of death of animals and humans. It is marked by an aberrant immune response to infection, resulting in extensive inflammation, organ dysfunction, and, in severe instances, organ failure. Recognizable symptoms and markers of sepsis encompass substantial elevations in body temperature, respiratory rate, hemoglobin levels, and alterations in immune cell counts, including neutrophils, monocytes, and basophils, along with increases in certain acute-phase proteins. In contrast to human medicine, veterinarians must take into account some species differences. This article provides a comprehensive overview of changes in the immune system during sepsis, placing particular emphasis on species variations and exploring potential future drugs and interventions. Hence, understanding the intricate balance of the immune responses during sepsis is crucial to develop effective treatments and interventions to improve the chances of recovery in animals suffering from this serious condition.

Combinational therapy of mesenchymal stem cell-derived extracellular vesicles and azithromycin improves clinical and histopathological recovery in CLP sepsis model

BACKGROUND

Sepsis is a syndrome that occurs following an infection and marked by severe inflammatory responses, and if not treated in time, it can lead to multi-organ failure syndrome and death. This study examines the effects of a novel combination therapy using azithromycin and mesenchymal stem cell-derived extracellular vesicles (EVs) on a cecal ligation and puncture (CLP) model of sepsis.

METHODS

Human Wharton's jelly-mesenchymal stem cells were cultured, characterized, and used to extract EVs. The CLP sepsis model was induced in mice, followed by treatments: saline, AZM, EVs, and combination therapy (A+E). Clinical sepsis scores were recorded 24 h post-treatment. Serum, peritoneal fluid, and organ tissues (kidney, liver, lung) were collected and analyzed for biochemical parameters (AST ALT, and creatinine), inflammatory markers, bacterial load, and histopathological changes.

RESULTS

The A+E combined treatment improved the clinical scores of septic mice. The administration of A+E reduced bacterial loads in the peritoneum of septic mice, contributing to effective control of infection. Inflammatory markers of neutrophils-to-lymphocytes ratio (NLR) and TNF-α serum levels were significantly lower in the combinational therapy group, indicating significant anti-inflammatory effect of this combination. Additionally, combination of AZM and EVs alleviated organ damage mainly within liver, kidneys and lungs. Based on histopathological assessments and biochemical parameters, there was diminished tissue damage as well as reduced inflammation, which is correlated with improved functions of these vital organs.

CONCLUSION

The combined use of azithromycin and EVs offers a promising therapeutic approach for sepsis by effectively controlling infection and modulating the inflammatory response.

Acute and Chronic Kidney Disease Worsen Outcomes in Experimental Sepsis

Key Points

Acute kidney disease (AKD) and CKD are common conditions associated with high rates of incident infection, and poor outcomes once infection have been established. We successfully modeled AKD and CKD in rodents and then administered a cecal slurry solution to create peritonitis and tracked sepsis severity, end organ injury, and inflammatory changes. Our results indicate that AKD mice are more susceptible to infection than CKD mice, developing an aggravated inflammatory response and suggests that this condition predisposes to disparate infection risk.

Background

Infection is a leading cause of morbidity in individuals with acute kidney disease (AKD) and CKD. However, there is significant difficulty in modeling infection into an animal host with preexisting kidney disease. We report a novel method of peritoneal infection induced via cecal slurry (CS) inoculation deployed into mice with experimental aristolochic acid–induced AKD and CKD.

Methods

AKD, CKD, and paired control mice were injected with sham, low, or higher doses of donor–recipient matched CS solution. Animal survival, sepsis severity, and change in GFR were tracked longitudinally throughout the study. Histology for kidney injury, flow cytometry, plasma cytokines, and evidence of indirect organ injury from sepsis were also assessed.

Results

Infected AKD mice experienced significantly heightened sepsis severity, with 100% mortality by 24 hours after high CS doses versus no mortality in control mice. In addition, AKD mice receiving lower CS doses developed dramatically increased proinflammatory cytokines and persistent cytopenias. Infected CKD mice also had worse outcomes than paired CKD controls, although less severe than in AKD mice. Interestingly, animals with AKD had worse outcomes than mice with CKD after any CS dose or time point after inoculation, despite higher baseline kidney function and less uremic sequela.

Conclusions

These data confirm that acute bacterial infection can be modeled in animals with established kidney disease and suggest that the clinical state of kidney disease (AKD versus CKD) may influence host susceptibility to infection more than the degree of kidney failure alone.

A novel model of urosepsis in mice developed by ureteral ligation and injection of Escherichia coli into the renal pelvis

Despite extensive investigations, urosepsis remains a life-threatening and high-mortality illness. The absence of widely acknowledged animal models for urosepsis prompted this investigation with the objective of formulating a replicable murine model. Eighty-four adult male C57BL/6J mice were arbitrarily distributed into three cohorts based on the concentration of the Escherichia coli (E. coli) solution administered into the renal pelvis: Sham, Low-grade sepsis (1.0 × 108 cfu/mL), and High-grade sepsis (1.0 × 109 cfu/mL). By fabricating a glass needle with a 100 μm outer diameter, bacterial leakage during renal pelvic injection was minimized. After the ureteral ligation, the mice were injected with this needle into the right renal pelvis (normal saline or E. coli solution, 1 ml/kg). Ten days post after E. coli injection, the mortality rates for the Low-grade sepsis and High-grade sepsis groups stood at 30 % and 100 %, respectively. Post-successful modeling, mice in the urosepsis cohort exhibited a noteworthy reduction in activity, body temperature, and white blood cell count within a 2-h timeframe. At the 24-h mark post-modeling, mice afflicted with urosepsis displayed compromised coagulation functionality. Concurrently, multiple organ dysfunction was confirmed as evidenced by markedly elevated levels of inflammatory factors (IL-6 and TNF-α) in four distinct organs (heart, lung, liver, and kidney). This study confirmed the feasibility of establishing a standardized mouse model of urosepsis by ureteral ligation and E. coli injection into the renal pelvis. A primary drawback of this model resides in the mice's diminished blood volume, rendering continuous blood extraction at multiple intervals challenging.

Extracellular Vesicles Derived from Human Adipose-Derived Mesenchymal Stem Cells Alleviate Sepsis-Induced Acute Lung Injury through a MicroRNA-150-5p-Dependent Mechanism

Extracellular vesicles (EVs) derived from human adipose mesenchymal stem cells (hADSCs) may exert a therapeutic benefit in alleviating sepsis-induced organ dysfunction by delivering cargos that include RNAs and proteins to target cells. The current study aims to explore the protective effect of miR-150-5p delivered by hADSC-EVs on sepsis-induced acute lung injury (ALI). We noted low expression of miR-150-5p in plasma and bronchoalveolar lavage fluid samples from patients with sepsis-induced ALI. The hADSC-EVs were isolated and subsequently cocultured with macrophages. It was established that hADSC-EVs transferred miR-150-5p to macrophages, where miR-150-5p targeted HMGA2 to inhibit its expression and, consequently, inactivated the MAPK pathway. This effect contributed to the promotion of M2 polarization of macrophages and the inhibition of proinflammatory cytokines. Further, mice were made septic by cecal ligation and puncture in vivo and treated with hADSC-EVs to elucidate the effect of hADSC-EVs on sepsis-induced ALI. The in vivo experimental results confirmed a suppressive role of hADSC-EVs in sepsis-induced ALI. Our findings suggest that hADSC-EV-mediated transfer of miR-150-5p may be a novel mechanism underlying the paracrine effects of hADSC-EVs on the M2 polarization of macrophages in sepsis-induced ALI.

Two murine models of sepsis: immunopathological differences between the sexes-possible role of TGFβ1 in female resistance to endotoxemia

Endotoxic shock (ExSh) and cecal ligature and puncture (CLP) are models that induce sepsis. In this work, we investigated early immunologic and histopathologic changes induced by ExSh or CLP models in female and male mice. Remarkable results showed that females supported twice the LD100 of LPS for males, CLP survival and CFU counts were similar between genders, high circulating LPS levels in ExSh mice and low levels of IgM anti-LPS in males. In the serum of ExSh males, TNF and IL-6 increased in the first 6 h, in CLP males at 12 h. In the liver of ExSh mice, TNF increased at 1.5 and 12 h, IL-1 at 6 h. TGFβ1 increased in females throughout the study and at 12 h in males. In CLP mice, IL-6 decreased at 12 h, TGFβ1 increased at 6-12 h in males and at 12 h in females. In the lungs of ExSh males, IL-1β increased at 1.5-6 h and TGFβ1 at 12 h; in females, TNF decrease at 6 h and TGFβ1 increased from 6 h; in CLP females, TNF and IL-1β decreased at 12 h and 1.5 h, respectively, and TGFβ1 increased from 6 h; in males, TGFβ1 increased at 12 h. In the livers of ExSh mice, signs of inflammation were more common in males; in the CLP groups, inflammation was similar but less pronounced. ExSh females had leucocytes with TGFβ1. The lungs of ExSh males showed patches of hyaline membranes and some areas of inflammatory cells, similar but fewer and smaller lesions were seen in male mice with CLP. In ExSh females, injuries were less extent than in males, similar pulmonary lesions were seen in female mice with CLP. ExSh males had lower levels of TGFβ1 than females, and even lower levels were seen in CLP males. We conclude that the ExSh was the most lethal model in males, associated with high levels of free LPS, low IgM anti-LPS, exacerbated inflammation and target organ injury, while females showed early TGFβ1 production in the lungs and less tissue damage. We didn't see any differences between CLP mice.

Prediction of severe CRS and determination of biomarkers in B cell-acute lymphoblastic leukemia treated with CAR-T cells

Introduction

CAR-T cell therapy is a novel approach in the treatment of hematological tumors. However, it is associated with life-threatening side effects, such as the severe cytokine release syndrome (sCRS). Therefore, predicting the occurrence and development of sCRS is of great significance for clinical CAR-T therapy. The study of existing clinical data by artificial intelligence may bring useful information.

Methods

By analyzing the heat map of clinical factors and comparing them between severe and non-severe CRS, we can identify significant differences among these factors and understand their interrelationships. Ultimately, a decision tree approach was employed to predict the timing of severe CRS in both children and adults, considering variables such as the same day, the day before, and initial values.

Results

We measured cytokines and clinical biomarkers in 202 patients who received CAR-T therapy. Peak levels of 25 clinical factors, including IFN-γ, IL6, IL10, ferritin, and D-dimer, were highly associated with severe CRS after CAR T cell infusion. Using the decision tree model, we were able to accurately predict which patients would develop severe CRS consisting of three clinical factors, classified as same-day, day-ahead, and initial value prediction. Changes in serum biomarkers, including C-reactive protein and ferritin, were associated with CRS, but did not alone predict the development of severe CRS.

Conclusion

Our research will provide significant information for the timely prevention and treatment of sCRS, during CAR-T immunotherapy for tumors, which is essential to reduce the mortality rate of patients.

Construction and validation of machine learning models for sepsis prediction in patients with acute pancreatitis

BACKGROUND

This study aimed to construct predictive models for the risk of sepsis in patients with Acute pancreatitis (AP) using machine learning methods and compared optimal one with the logistic regression (LR) model and scoring systems.

METHODS

In this retrospective cohort study, data were collected from the Medical Information Mart for Intensive Care III (MIMIC III) database between 2001 and 2012 and the MIMIC IV database between 2008 and 2019. Patients were randomly divided into training and test sets (8:2). The least absolute shrinkage and selection operator (LASSO) regression plus 5-fold cross-validation were used to screen and confirm the predictive factors. Based on the selected predictive factors, 6 machine learning models were constructed, including support vector machine (SVM), K-nearest neighbour (KNN), multi-layer perceptron (MLP), LR, gradient boosting decision tree (GBDT) and adaptive enhancement algorithm (AdaBoost). The models and scoring systems were evaluated and compared using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and the area under the curve (AUC).

RESULTS

A total of 1, 672 patients were eligible for participation. In the training set, 261 AP patients (19.51%) were diagnosed with sepsis. The predictive factors for the risk of sepsis in AP patients included age, insurance, vasopressors, mechanical ventilation, Glasgow Coma Scale (GCS), heart rate, respiratory rate, temperature, SpO2, platelet, red blood cell distribution width (RDW), International Normalized Ratio (INR), and blood urea nitrogen (BUN). The AUC of the GBDT model for sepsis prediction in the AP patients in the testing set was 0.985. The GBDT model showed better performance in sepsis prediction than the LR, systemic inflammatory response syndrome (SIRS) score, bedside index for severity in acute pancreatitis (BISAP) score, sequential organ failure assessment (SOFA) score, quick-SOFA (qSOFA), and simplified acute physiology score II (SAPS II).

CONCLUSION

The present findings suggest that compared to the classical LR model and SOFA, qSOFA, SAPS II, SIRS, and BISAP scores, the machine learning model-GBDT model had a better performance in predicting sepsis in the AP patients, which is a useful tool for early identification of high-risk patients and timely clinical interventions.

Sepsis-induced endothelial dysfunction drives acute-on-chronic liver failure through Angiopoietin-2-HGF-C/EBPβ pathway

BACKGROUND AND AIMS

Acute-on-chronic liver failure (ACLF) is an acute liver and multisystem failure in patients with previously stable cirrhosis. A common cause of ACLF is sepsis secondary to bacterial infection. Sepsis-associated ACLF involves a loss of differentiated liver function in the absence of direct liver injury, and its mechanism is unknown. We aimed to study the mechanism of sepsis-associated ACLF using a novel mouse model.

APPROACH AND RESULTS

Sepsis-associated ACLF was induced by cecal ligation and puncture procedure (CLP) in mice treated with thioacetamide (TAA). The combination of TAA and CLP resulted in a significant decrease in liver synthetic function and high mortality. These changes were associated with reduced metabolic gene expression and increased CCAAT enhancer binding protein beta (C/EBPβ) transcriptional activity. We found that C/EBPβ binding to its target gene promoters was increased. In humans, C/EBPβ chromatin binding was similarly increased in the ACLF group compared with control cirrhosis. Hepatocyte-specific Cebpb knockout mice had reduced mortality and increased gene expression of hepatocyte differentiation markers in TAA/CLP mice, suggesting that C/EBPβ promotes liver failure in these mice. C/EBPβ activation was associated with endothelial dysfunction, characterized by reduced Angiopoietin-1/Angiopoietin-2 ratio and increased endothelial production of HGF. Angiopoietin-1 supplementation or Hgf knockdown reduced hepatocyte C/EBPβ accumulation, restored liver function, and reduced mortality, suggesting that endothelial dysfunction induced by sepsis drives ACLF through HGF-C/EBPβ pathway.

CONCLUSIONS

The transcription factor C/EBPβ is activated in both mouse and human ACLF and is a potential therapeutic target to prevent liver failure in patients with sepsis and cirrhosis.

Clinical Phenotypes of Sepsis in a Cohort of Hospitalized Patients According to Infection Site

OBJECTIVES

Clinical sepsis phenotypes may be defined by a wide range of characteristics such as site of infection, organ dysfunction patterns, laboratory values, and demographics. There is a paucity of literature regarding the impact of site of infection on the timing and pattern of clinical sepsis markers. This study hypothesizes that important phenotypic variation in clinical markers and outcomes of sepsis exists when stratified by infection site.

DESIGN

Retrospective cohort study.

SETTING

Five hospitals within the Wake Forest Health System from June 2019 to December 2019.

PATIENTS

Six thousand seven hundred fifty-three hospitalized adults with a discharge International Classification of Diseases, 10th Revision code for acute infection who met systemic inflammatory response syndrome (SIRS), quick Sepsis-related Organ Failure Assessment (qSOFA), or Sequential Organ Failure Assessment (SOFA) criteria during the index hospitalization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome of interest was a composite of 30-day mortality or shock. Infection site was determined by a two-reviewer process. Significant demographic, vital sign, and laboratory result differences were seen across all infection sites. For the composite outcome of shock or 30-day mortality, unknown or unspecified infections had the highest proportion (21.34%) and CNS infections had the lowest proportion (8.11%). Respiratory, vascular, and unknown or unspecified infection sites showed a significantly increased adjusted and unadjusted odds of the composite outcome as compared with the other infection sites except CNS. Hospital time prior to SIRS positivity was shortest in unknown or unspecified infections at a median of 0.88 hours (interquartile range [IQR], 0.22-5.05 hr), and hospital time prior to qSOFA and SOFA positivity was shortest in respiratory infections at a median of 54.83 hours (IQR, 9.55-104.67 hr) and 1.88 hours (IQR, 0.47-17.40 hr), respectively.

CONCLUSIONS

Phenotypic variation in illness severity and mortality exists when stratified by infection site. There is a significantly higher adjusted and unadjusted odds of the composite outcome of 30-day mortality or shock in respiratory, vascular, and unknown or unspecified infections as compared with other sites.

Development and validation of a nomogram for predicting sepsis in patients with pyogenic liver abscess

Pyogenic liver abscess (PLA) is a severe condition that significantly increases the risk of sepsis. However, there is a notable dearth of research regarding the prediction of sepsis in PLA patients. The objective of this study was to develop and validate a prognostic nomogram for predicting sepsis in PLA patients. A total of 206 PLA patients were enrolled in our study, out of which 60 individuals (29.1%) met the Sepsis-3 criteria. Independent risk factors for sepsis were identified through univariate and multivariate logistic regression analyses. Subsequently, a nomogram was developed based on age, positive blood culture, procalcitonin, alanine aminotransferase, blood urea nitrogen, and D-dimer. The nomogram demonstrated excellent calibration and discrimination, as evidenced by the area under the receiver operating characteristic curve (AUC) values of 0.946 (95% confidence interval [CI], 0.912-0.979) and 0.980 (95%CI 0.951-1.000) in the derivation and validation cohorts, respectively. Furthermore, decision-curve analysis confirmed the clinical utility of the nomogram. This study provides valuable insights for the prevention of sepsis in PLA patients and underscores the potential application of the prognostic nomogram in clinical practice.

Oxidative stress and DNA damage in critically ill patients with sepsis

The aim of our study was to assess the oxidative stress and inflammatory status in critically ill patients with sepsis as well as their relationship with the level of DNA damage. The study also evaluated the influence of all analyzed parameters on the outcome of the patients. The study included 27 critically ill patients with sepsis and 20 healthy subjects. Comet Assay was used for the measurement of the level of DNA damage, expressed as genetic damage index (GDI). Both oxidative stress parameters and the antioxidant parameters were obtained spectrophotometrically. The standard laboratory methods and the appropriate autoanalyzers were performed for determination the parameters of inflammation. A higher level of oxidative stress and more pronounced inflammation were found in the patients with sepsis compared to healthy subjects. The activity of the antioxidant enzymes was statistically declined in patients with sepsis, so that the most notable differences between two groups of participants were found for the activity of superoxide dismutase (SOD) (p = 0.004). Comet assay indicated that patients with sepsis had significantly higher GDI compared to healthy subjects (p < 0.001), which positively correlated with the concentration of superoxide anion radical (О₂^-) (r = 0.497, p = 0.010), and nitrites (NО₂^-) (r = 0.473, p = 0.015), as well with the concentration of C reactive protein (CRP) (r = 0.460, p = 0.041). Regression analysis confirmed that patients' age (p = 0.033), the level of О₂^- (p = 0.007), CRP concentration (p = 0.029) and GDI (p = 0.001) increased the risk of lethal outcome in critically ill patients with sepsis. In conclusion, critically ill patients with sepsis have a higher degree of oxidative stress and inflammation which contribute to a higher level of DNA damage. Consequently, above mentioned parameters, including patients' age, adversely affect the outcome of critically ill patients with sepsis.

Protective effect of the novel cyclic peptide ASK0912 on mice with sepsis induced by Acinetobacter baumannii

BACKGROUND

Sepsis has become a global health concern owing to its increasing incidence and high mortality rate. In the present study, we investigated a novel drug candidate ASK0912 on its protective effects in mice with Acinetobacter baumannii 20-1-induced sepsis, and studied the related mechanisms.

MATERIAL AND METHODS

To analyze the protective effect of ASK0912 on septic mice, survival rates, body temperature, organ and blood bacterial loads, white blood cell and platelet counts, organ damage, and cytokine levels were determined.

RESULTS

ASK0912 remarkably increased the survival rate of mice with sepsis induced by A. baumannii 20-1 at a low dose of 0.6 mg/kg. Rectal temperature measurements showed that ASK0912 treatment prevented the body temperature decrease of septic mice to some extent. Treatment with ASK0912 can notably reduce the organ and blood bacterial loads and alleviate platelet count reduction due to sepsis. ASK0912 attenuated organ damage, including reduced levels of total bile acids, urea, and creatinine, aggregation of inflammatory cells, and mitigation of structural changes in septic mice, as demonstrated by biochemical analysis and hematoxylin & eosin staining. Additionally, multiplex assay showed that abnormally increased cytokine levels (IL-1β, IL-3, IL-5, IL-6, IL-10, IL-13, MCP-1, RANTES, KC, MIP-1α, MIP-1β, and G-CSF) in septic mice decreased after ASK0912 treatment.

CONCLUSIONS

ASK0912 can not only improve the survival rate, hypothermia, lower the bacterial loads in the organs and blood, but also alleviate the pathophysiological manifestations such as intravascular coagulation abnormalities, organ damages, and immune system disorder of sepsis mice induced by A. baumannii 20-1.

Advances in Rodent Experimental Models of Sepsis

In the development of therapeutic strategies for human diseases, preclinical experimental models have a key role. However, the preclinical immunomodulatory therapies developed using rodent sepsis were not successful in human clinical trials. Sepsis is characterized by a dysregulated inflammation and redox imbalance triggered by infection. Human sepsis is simulated in experimental models using methods that trigger inflammation or infection in the host animals, most often mice or rats. It remains unknown whether the characteristics of the host species, the methods used to induce sepsis, or the molecular processes focused upon need to be revisited in the development of treatment methods that will succeed in human clinical trials. Our goal in this review is to provide a survey of existing experimental models of sepsis, including the use of humanized mice and dirty mice, and to show how these models reflect the clinical course of sepsis. We will discuss the strengths and limitations of these models and present recent advances in this subject area. We maintain that rodent models continue to have an irreplaceable role in studies toward discovering treatment methods for human sepsis.

miR-926-3p influences myocardial injury in septic mice through regulation of mTOR signaling pathway by targeting TSC1

BACKGROUND

The purpose of this study is to investigate the influence of miR-926-3p on myocardial injury and its mechanisms.

METHODS

An animal model of sepsis was constructed by CLP, and animals were randomly divided into 4 groups: C group, miR-926-3p inhibitor group, CLP + NC group, and CLP + miR-926-3p inhibitor group.

RESULTS

Compared with those in C group, echocardiographic parameters remarkably declined in CLP + NC group. Compared with CLP + NC group, miR-926-3p inhibitor group indicated elevated echocardiographic parameters in mice, pathological improvement tendency of myocardial tissues and distinct reduction in cardiomyocyte apoptosis. It could be observed by electron microscopy that the number of lysosomes in miR-926-3p inhibitor group was greatly increased relative to CLP + NC group. Immunofluorescence exhibited that the number of green fluorescent puncta was significantly higher in miR-926-3p inhibitor group as compared to that in CLP + NC group. The autophagic flow was verified by observing the relative expression of LC3II at different times. The results of Western blotting manifested that miR-926-3p inhibitor up-regulated mTOR-related protein expressions and down-regulated the protein expression of p-mTOR. LPS was adopted to induce cardiomyocyte injury in vitro, and the results confirmed that, identical to in vivo experiments, miR-926-3p inhibitor was able to up-regulate the protein expressions of mTOR-related protein and down-regulate p-mTOR protein expression in cardiomyocytes. After addition of MHY1485, The expression of mTOR-related proteins changes in each group.

CONCLUSION

Inhibition of miR-926-3p enhances autophagy through regulation of the mTOR signaling pathway, thus ameliorating myocardial injury in septic mice.

Development of a High-Throughput Urosepsis Mouse Model

Murine sepsis models are typically polymicrobial, and are associated with high mortality. We aimed to develop a high-throughput murine model that mimics a slow-paced, monomicrobial sepsis originating from the urinary tract. A total of 23 male C57Bl/6 mice underwent percutaneous insertion of a 4 mm catheter into the bladder using an ultrasound-guided method, previously developed by our group. The following day, Proteus mirabilis (PM) was introduced percutaneously in the bladder in three groups: g1-50 µL 1 × 108 CFU/mL solution (n = 10); g2-50 µL 1 × 107 CFU/mL solution (n = 10); and g3 (sham mice)-50 µL sterile saline (n = 3). On day 4, mice were sacrificed. The number of planktonic bacteria in urine, adherent to catheters, and adherent to/invaded into the bladder and spleen was assessed. Cell-free DNA, D-dimer, thrombin-antithrombin complex (TAT), and 32 pro-/anti-inflammatory cytokines/chemokines were quantified in the blood. All mice survived the 4 day postinterventional period. Mean weight loss was 11% in g1, 9% in g2, and 3% in the control mice. Mean urine CFU counts were highest in group 1. All catheters showed high catheter-adhered bacterial counts. Of the infected mice, 17/20 had CFU counts in the splenic tissue, indicating septicemia. Plasma levels of cell-free DNA, D-dimer, and the proinflammatory cytokines IFN-γ, IL-6, IP-10, MIG, and G-CSF were significantly elevated in infected mice versus controls. We present a reproducible, monomicrobial murine model of urosepsis that does not lead to rapid deterioration and death, and is useful for studying prolonged urosepsis.

Establishing the role of the FES tyrosine kinase in the pathogenesis, pathophysiology, and severity of sepsis and its outcomes

Introduction

Sepsis is a result of initial over-activation of the immune system in response to an infection or trauma that results in reduced blood flow and life-threatening end-organ damage, followed by suppression of the immune system that prevents proper clearance of the infection or trauma. Because of this, therapies that not only limit the activation of the immune system early on, but also improve blood flow to crucial organs and reactivate the immune system in late-stage sepsis, may be effective treatments. The tyrosine kinase FES may fulfill this role. FES is present in immune cells and serves to limit immune system activation. We hypothesize that by enhancing FES in early sepsis and inhibiting its effects in late sepsis, the severity and outcome of septic illness can be improved.

Methods and analysis

In vitro and in vivo modeling will be performed to determine the degree of inflammatory signaling, cytokine production, and neutrophil extracellular trap (NET) formation that occurs in wild-type (WT) and FES knockout (FES-/- ) mice. Clinically available treatments known to enhance or inhibit FES expression (lorlatinib and decitabine, respectively), will be used to explore the impact of early vs. late FES modulation on outcomes in WT mice. Bioinformatic analysis will be performed to examine FES expression levels in RNA transcriptomic data from sepsis patient cohorts, and correlate FES expression data with clinical outcomes (diagnosis of sepsis, illness severity, hospital length-of-stay).

Ethics and dissemination

Ethics approval pending from the Queen's University Health Sciences & Affiliated Teaching Hospitals Research Ethics Board. Results will be disseminated through scientific publications and through lay summaries to patients and families.

Early effects of bone marrow-derived mononuclear cells on lung and kidney in experimental sepsis

BACKGROUND

In experimental sepsis, functional and morphological effects of bone marrow-derived mononuclear cell (BMDMC) administration in lung tissue have been evaluated 1 and 7 days after therapy. However, to date no study has evaluated the early effects of BMDMCs in both lung and kidney in experimental polymicrobial sepsis.

MATERIAL AND METHODS

Twenty-five female C57BL/6 mice were randomly divided into the following groups: 1) cecal ligation and puncture (CLP)-induced sepsis; and 2) Sham (surgical procedure without CLP). After 1 h, CLP animals received saline (NaCl 0.9%) (CLP-Saline) or 10⁶ BMDMCs (CLP-Cell) via the jugular vein. At 6, 12, and 24 h after saline or BMDMC administration, lungs and kidneys were removed for histology and molecular biology analysis.

RESULTS

In lungs, CLP-Saline, compared to Sham, was associated with increased lung injury score (LIS) and keratinocyte chemoattractant (KC) mRNA expression at 6, 12, and 24 h. BMDMCs were associated with reduced LIS and KC mRNA expression regardless of the time point of analysis. Interleukin (IL)- 10 mRNA content was higher in CLP-Cell than CLP-Saline at 6 and 24 h. In kidney tissue, CLP-Saline, compared to Sham, was associated with tubular cell injury and increased neutrophil gelatinase-associated lipocalin (NGAL) levels, which were reduced after BMDMC therapy at all time points. Surface high-mobility-group-box (HMGB)- 1 levels were higher in CLP-Saline than Sham at 6, 12, and 24 h, whereas nuclear HMGB-1 levels were increased only at 24 h. BMDMCs were associated with decreased surface HMGB-1 and increased nuclear HMGB-1 levels. Kidney injury molecule (KIM)- 1 and IL-18 gene expressions were reduced in CLP-Cell compared to CLP-Saline at 12 and 24 h.

CONCLUSION

In the present experimental polymicrobial sepsis, early intravenous therapy with BMDMCs was able to reduce lung and kidney damage in a time-dependent manner. BMDMCs thus represent a potential therapy in well-known scenarios of sepsis induction.

PURPOSE

To evaluate early bone marrow-derived mononuclear cell (BMDMC) therapy on lung and kidney in experimental polymicrobial sepsis.

METHODS

Twenty-five female C57BL/6 mice were randomly divided into the following groups: cecal ligation and puncture (CLP)-induced sepsis; and sham (surgical procedure without CLP). After 1 h, CLP animals received saline (CLP-saline) or 10⁶ BMDMCs (CLP-cell) via the jugular vein. Lungs and kidneys were evaluated for histology and molecular biology after 6, 12, and 24 h.

RESULTS

In lungs, BMDMCs reduced the lung injury score and keratinocyte chemoattractant mRNA expression regardless of the time point of analysis; interleukin-10 mRNA content was higher in CLP-cell than CLP-saline at 6 and 24 h. In kidneys, BMDMCs reduced neutrophil gelatinase-associated lipocalin levels at all time points. BMDMCs decreased surface high mobility group box (HMGB)- 1 but increased nuclear HMGB-1 levels.

CONCLUSION

Early BMDMC therapy reduced lung and kidney damage in a time-dependent manner.

Specificity of Presepsin as a Biomarker of Bacterial Infection in Mouse Sepsis Models

INTRODUCTION

Since its discovery in 2002, presepsin (P-SEP) has been reported to be useful in the early diagnosis of sepsis and has been evaluated in many clinical studies. However, as antibodies that bind to mouse P-SEP were previously unavailable, serum P-SEP levels in mice are limited. This study used a P-SEP enzyme-linked immunosorbent assay kit to evaluate the changes in serum P-SEP levels in mouse sepsis models compared with changes in other inflammatory markers and determine whether P-SEP can function as a biomarker specific to bacterial infections.

METHODS

Sepsis was induced in mice via cecal ligation and puncture (CLP), induction with lipopolysaccharide (LPS), and cecal ligation (CL) model was created as a control for the CLP model, following which clinical biomarkers (P-SEP, C-reactive protein, and procalcitonin) were evaluated.

RESULTS

The 48-h survival rates in the CLP, CL, and LPS-induced sepsis models were 67%, 89%, and 57%, respectively. Serum C-reactive protein levels did not increase in the CLP and CL models within 24 h but significantly increased in the LPS-induced sepsis model. Serum procalcitonin levels increased in the CLP and CL models and especially increased in the LPS-induced sepsis model. In contrast, an increase in serum P-SEP level was found in the CLP model at 6 h compared with those at baseline, the CL, and LPS-induced sepsis models.

CONCLUSIONS

Mouse P-SEP is elevated early in infection and more specific to bacterial infection compared with other biomarkers.

Modeling sepsis, with a special focus on large animal models of porcine peritonitis and bacteremia

Infectious diseases, which often result in deadly sepsis or septic shock, represent a major global health problem. For understanding the pathophysiology of sepsis and developing new treatment strategies, reliable and clinically relevant animal models of the disease are necessary. In this review, two large animal (porcine) models of sepsis induced by either peritonitis or bacteremia are introduced and their strong and weak points are discussed in the context of clinical relevance and other animal models of sepsis, with a special focus on cardiovascular and immune systems, experimental design, and monitoring. Especially for testing new therapeutic strategies, the large animal (porcine) models represent a more clinically relevant alternative to small animal models, and the findings obtained in small animal (transgenic) models should be verified in these clinically relevant large animal models before translation to the clinical level.

Decreased VEGFA alleviates the symptoms of LPS-induced sepsis in a mouse model by inhibiting glycolysis and thereby regulating the polarization of macrophages

The immune imbalance caused by excessive inflammatory reactions is the primary cause of sepsis. Macrophages with M1 and M2 polarization states are important immune cells that regulate the balance of the inflammatory response in sepsis. Encouraging the conversion of macrophages from the M1 to the M2 type is an important strategy for relieving sepsis. Here, we demonstrated the upregulation of vascular endothelial growth factor A (VEGFA) in a mouse model of sepsis. Then, siRNA technology was applied to inhibit the expression of VEGFA in macrophages. Flow cytometry and RT‒qPCR results showed that low expression of VEGFA inhibited LPS-induced M1 polarization of macrophages. Decreased VEGFA was also proven to lower TNF-α, IL-1β, and IL-6 secretion by LPS-induced macrophages. In addition, the effects of knocking down VEGFA on the energy metabolism pattern of macrophages were investigated by glycolysis pressure tests and mitochondrial pressure tests, and VEGFA knockdown reversed the induction of glycolysis in macrophages by LPS. The mitochondrial content and ATP content results also confirmed this finding. After the tail vein of septic mice was injected with macrophages transfected with si-VEGFA, the liver and kidney damage and the pathological conditions of the lung were alleviated. The secretion of TNF-α and IL-6 was decreased, while IL-10 was increased in their serum. Immunohistochemical staining revealed decreased expression of CD86 and increased expression of CD206 in the si-VEGFA group. This study demonstrates that decreased VEGFA inhibits glycolysis and thus inhibits LPS-induced M1 polarization of macrophages, ultimately relieving sepsis.

Renoprotective Effects of Luteolin: Therapeutic Potential for COVID-19-Associated Acute Kidney Injuries

Acute kidney injury (AKI) has been increasingly reported in critically-ill COVID-19 patients. Moreover, there was significant positive correlation between COVID-19 deaths and renal disorders in hospitalized COVID-19 patients with underlying comorbidities who required renal replacement therapy. It has suggested that death in COVID-19 patients with AKI is 3-fold higher than in COVID-19 patients without AKI. The pathophysiology of COVID-19-associated AKI could be attributed to unspecific mechanisms, as well as COVID-19-specific mechanisms such as direct cellular injury, an imbalanced renin-angiotensin-aldosterone system, pro-inflammatory cytokines elicited by the viral infection and thrombotic events. To date, there is no specific treatment for COVID-19 and its associated AKI. Luteolin is a natural compound with multiple pharmacological activities, including anticoronavirus, as well as renoprotective activities against kidney injury induced by sepsis, renal ischemia and diverse nephrotoxic agents. Therefore, in this review, we mechanistically discuss the anti-SARS-CoV-2 and renoprotective activities of luteolin, which highlight its therapeutic potential in COVID-19-AKI patients.

Olmesartan Ameliorates Organ Injury and Mortality in Rats With Peritonitis-Induced Sepsis

INTRODUCTION

Sepsis and related complications lead to high morbidity and mortality in humans and animals. Olmesartan medoxomil (OLM), a nonpeptide angiotensin II type 1 receptor blocker, has antiinflammatory and antioxidative effects in various experimental animal models. The present study aimed to investigate whether OLM protects against sepsis in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP).

METHODS

Sepsis was induced by CLP in anesthetized rats. OLM was administered intraperitoneally 3 h after CLP onset. Hemodynamic, biochemical, and inflammatory parameters were analyzed.

RESULTS

The administration of OLM in CLP rats significantly improved their survival rate. Moreover, OLM mitigated CLP-induced hypotension and organ injury (indicated by biochemical parameters), but not tachycardia. OLM significantly reduced the plasma levels of interleukin-6 and nitric oxide.

CONCLUSIONS

OLM markedly attenuated CLP-induced hypotension and organ injury, and hence improved survival by inhibiting the inflammatory response and nitrosative stress in this clinically relevant model of sepsis.

Dichloroacetate improves systemic energy balance and feeding behavior during sepsis

Sepsis is a life-threatening organ dysfunction caused by dysregulated host response to an infection. The metabolic aberrations associated with sepsis underly an acute and organism-wide hyperinflammatory response and multiple organ dysfunction; however, crosstalk between systemic metabolomic alterations and metabolic reprogramming at organ levels remains unknown. We analyzed substrate utilization by the respiratory exchange ratio, energy expenditure, metabolomic screening, and transcriptional profiling in a cecal ligation and puncture model to show that sepsis increases circulating free fatty acids and acylcarnitines but decreases levels of amino acids and carbohydrates, leading to a drastic shift in systemic fuel preference. Comparative analysis of previously published metabolomics from septic liver indicated a positive correlation with hepatic and plasma metabolites during sepsis. In particular, glycine deficiency was a common abnormality of the plasma and liver during sepsis. Interrogation of the hepatic transcriptome in septic mice suggested that the septic liver may contribute to systemic glycine deficiency by downregulating genes involved in glycine synthesis. Interestingly, intraperitoneal injection of the pyruvate dehydrogenase kinase (PDK) inhibitor dichloroacetate reversed sepsis-induced anorexia, energy imbalance, inflammation, dyslipidemia, hypoglycemia, and glycine deficiency. Collectively, our data indicated that PDK inhibition rescued systemic energy imbalance and metabolic dysfunction in sepsis partly through restoration of hepatic fuel metabolism.

Results of Structural and Bacteriological Analysis of the Mouse Adrenal Glands in a Sepsis Model

The article presents the results of histological and bacteriological analysis of the adrenal glands in two models of sepsis caused by intraperitoneal administration of Pseudomonas aeruginosa strains 1623 and 5266 to sexually mature male C57BL/6 mice. In both models, histological changes in the adrenal glands in the dynamics of sepsis consist in cell destruction and decrease in the absolute areas of the zona glomerulosa, columnar part of the zona fasciculata, and medulla, the development of venous congestion in the absence of pronounced signs of leukocytic infiltration. Most adrenocortical cells of the zona glomerulosa and chromaffin cells of the medulla show signs of destruction. The columnar part of the zona fasciculata loses normal architectonics, the cells undergo degeneration and apoptosis, a significant part of cells in the deep layers of the zona fasciculata remain intact, but do not show tinctorial and ultrastructural signs of steroidogenesis. The active growth of P. aeruginosa colonies from adrenal homogenates in both models already in the first hours after infection of animals makes it possible to associate the revealed structural changes in the adrenal glands with the direct negative effect of P. aeruginosa, and high levels of mRNA of proinflammatory cytokines in the adrenal tissues raise the question of the possible synthesis of these modulators of inflammation in the adrenal parenchyma of septic animals.

Comparison of Single and Repeated Dosing of Anti-Inflammatory Human Umbilical Cord Mesenchymal Stromal Cells in a Mouse Model of Polymicrobial Sepsis

Mesenchymal stromal cells (MSCs) ameliorate pre-clinical sepsis and sepsis-associated acute kidney injury (SA-AKI) but clinical trials of single-dose MSCs have not indicated robust efficacy. This study investigated immunomodulatory effects of a novel MSC product (CD362-selected human umbilical cord-derived MSCs [hUC-MSCs]) in mouse endotoxemia and polymicrobial sepsis models. Initially, mice received intra-peritoneal (i.p.) lipopolysaccharide (LPS) followed by single i.p. doses of hUC-MSCs or vehicle. Next, mice underwent cecal ligation and puncture (CLP) followed by intravenous (i.v.) doses of hUC-MSCs at 4 h or 4 and 28 h. Analyses included serum/plasma assays of biochemical indices, inflammatory mediators and the AKI biomarker NGAL; multi-color flow cytometry of peritoneal macrophages (LPS) and intra-renal immune cell subpopulations (CLP) and histology/immunohistochemistry of kidney (CLP). At 72 h post-LPS injections, hUC-MSCs reduced serum inflammatory mediators and peritoneal macrophage M1/M2 ratio. Repeated, but not single, hUC-MSC doses administered at 48 h post-CLP resulted in lower serum concentrations of inflammatory mediators, lower plasma NGAL and reversal of sepsis-associated depletion of intra-renal T cell and myeloid cell subpopulations. Hierarchical clustering analysis of all 48-h serum/plasma analytes demonstrated partial co-clustering of repeated-dose hUC-MSC CLP animals with a Sham group but did not reveal a distinct signature of response to therapy. It was concluded that repeated doses of CD362-selected hUC-MSCs are required to modulate systemic and local immune/inflammatory events in polymicrobial sepsis and SA-AKI. Inter-individual variability and lack of effect of single dose MSC administration in the CLP model are consistent with observations to date from early-phase clinical trials.

Endogenous Sulfur Dioxide Improves the Survival Rate of Sepsis by Improving the Oxidative Stress Response during Lung Injury

Objective

To explore the regulation of endogenous sulfur dioxide on oxidative stress in lung injury induced by sepsis.

Method

Forty male Sprague Dawley rats were divided into control, sepsis, sepsis + SO2, and SO2 group randomly used to observe survival rate. The other group of twenty-eight rats were randomly divided as the same manner for mechanism research. The number of WBCS and the percentage of PMN cells were calculated. The microphotographs of morphological changes and the index of quantitative assessment (IQA) of lung tissues were calculated. The ratio of wet/dry (W/D) of lung tissues was calculated. Levels of H2O2, MDA, NO, MPO, SOD, GSH-px, and TNF-α in plasma and lung tissues were measured.

Result

The number of WBCS and the percentage of PMN cells decreased in sepsis (p all < 0.05), and rebound in sepsis+SO2 (p all < 0.05). The IQA and W/D of lung tissues increased in sepsis (p for W/D < 0.05), and decreased in sepsis+SO2 (p all < 0.05). H2O2 and MDA of plasma and lung tissues increased in sepsis (p all < 0.05) and rebound in sepsis+SO2 (p for H2O2 of plasma and lung tissues <0.05). NO and MPO of plasma and lung tissues increased in sepsis (p for NO and MPO of lung tissues <0.05) and rebound in sepsis+SO2 (p all < 0.05). SOD of plasma and lung tissues in sepsis group decreased (p all <0.05) and increased in sepsis+SO2 (p all < 0.05). GSH-px of plasma and lung tissues decreased in sepsis (p for plasma <0.05) and increased in sepsis+SO2 (p for GSH-px of lung tissues <0.05). TNF-α of plasma and lung tissues increased in sepsis (p all<0.05) and decreased in sepsis+SO2 (p for lung tissue <0.05).

Conclusion

Endogenous sulfur dioxide improves the survival rate of sepsis by improving the oxidative stress response during lung injury.

miR-197 Participates in Lipopolysaccharide-Induced Cardiomyocyte Injury by Modulating SIRT1

Sepsis is a systemic inflammation and is capable of inducing myocarditis, which is a major leading cause of death in patients. Studies have found that miR-197 is correlated with the prognosis of patients with inflammatory heart disease, but its effect on sepsis-induced cardiomyocyte injury remains unclear. We treated H9c2 cells with lipopolysaccharide (LPS), then detected the cell viability via the cell counting kit-8 (CCK-8) assay and quantified miR-197 expression via quantitative real-time polymerase chain reaction (qRT-PCR). Then, we investigated the role of miR-197 in LPS-induced H9c2 cells by CCK-8 assay, flow cytometry, lactate dehydrogenase (LDH) measurement, enzyme-linked immunosorbent assay (ELISA), qRT-PCR, and western blot. Subsequently, silent information regulator 1 (SIRT1) was downregulated in H9c2 cells to explore its interaction with miR-197 under LPS induction. LPS induced miR-197 overexpression in H9c2 cells. LPS restrained viability, the expressions of B-cell lymphoma-2 (Bcl-2) and SIRT1, but promoted apoptosis, LDH release, and levels of interleukin-6 (IL-6), interleukin-1β (IL-1β), acetyl (AC)-p53, BCL2-associated X (Bax), and cleaved caspase-3 in H9c2 cells. miR-197 inhibition reversed the effects of LPS on H9c2 cells. The protective role of miR-197 downregulation in LPS-induced H9c2 cells was reversed by SIRT1 silencing. miR-197 contributed to LPS-induced cardiomyocyte injury by modulating SIRT1, which might be used as a molecular marker in the management of sepsis.

Transfusion of fresh washed platelets does not prevent experimental polymicrobial-induced septic shock in mice

INTRODUCTION

The specific role of platelets during sepsis is not yet fully understood, probably related to the paradox of platelets being potentially beneficial but also deleterious via their thrombotic functions.

OBJECTIVE

To evaluate the impact of thrombocytopenia on septic shock in mice and to investigate whether transfusion of fresh washed platelets, either fully functional or with impaired hemostatic properties, might have beneficial effects.

METHODS

Septic shock was induced by cecal ligation and puncture (CLP). Experimental depletion of circulating platelets was induced with a rat anti-mouse GPIbα monoclonal antibody. Transfusion of either wild-type washed platelets, platelets treated with the antiplatelet drugs acetylsalicylic acid (ASA) and clopidogrel, or GPIIbIIIa-deficient washed platelets treated with ASA and clopidogrel was performed 4 h after CLP surgery.

RESULTS

Depletion of circulating platelets negatively affected septic shock, worsening systemic inflammation, coagulopathy, organ damage, and mortality, raising the question of whether a higher platelet count could be protective. Transfusion of fully functional platelets or platelets with combined treatment with ASA and clopidogrel, with or without additional GPIIbIIIa deficiency, afforded an immediate return of circulating platelet counts to their initial values before surgery. However, transfusion of each of the three types of platelets did not prevent arterial hypotension, inflammatory response, coagulopathy, and organ damage during septic shock.

CONCLUSION

Depletion of circulating platelets negatively affects septic shock, while transfusion of washed platelets has no significant beneficial effect in mice.

Is rosuvastatin protective against sepsis-associated encephalopathy? A secondary analysis of the SAILS trial

BACKGROUND

Sepsis is a common cause of death in emergency departments and sepsis-associated encephalopathy (SAE) is a major complication. Rosuvastatin may play a neuroprotective role due to its protective effects on the vascular endothelium and its anti-inflammatory functions. Our study aimed to explore the potential protective function of rosuvastatin against SAE.

METHODS

Sepsis patients without any neurological dysfunction on admission were prospectively enrolled in the "Rosuvastatin for Sepsis-Associated Acute Respiratory Distress Syndrome" study (SAILS trial, ClinicalTrials.gov number: NCT00979121). Patients were divided into rosuvastatin and placebo groups. This is a secondary analysis of the SAILS dataset. Baseline characteristics, therapy outcomes, and adverse drug events were compared between groups.

RESULTS

A total of 86 patients were eligible for our study. Of these patients, 51 were treated with rosuvastatin. There were significantly fewer cases of SAE in the rosuvastatin group than in the placebo group (32.1% vs. 57.1%, P=0.028). However, creatine kinase levels were significantly higher in the rosuvastatin group than in the placebo group (233 [22-689] U/L vs. 79 [12-206] U/L, P=0.034).

CONCLUSION

Rosuvastatin appears to have a protective role against SAE but may result in a higher incidence of adverse events.

Riboflavin did not provide anti-inflammatory or antioxidant effects in an experimental model of sepsis

We aimed to evaluate whether the administration of riboflavin to septic animals reduces inflammation, oxidative stress, organ dysfunction, and mortality. C57BL/6 mice, 6-8 weeks old, were allocated to the study group (polymicrobial sepsis induced by cecal ligation and puncture (CLP) + antibiotic + iv riboflavin), control (CLP + antibiotic + iv saline), or naïve (non-operated controls). Serum concentrations of alanine aminotransferase (ALT), creatine kinase-MB (CK-MB), urea, and creatinine, and markers of inflammation [interleukin (IL)-6, tumor necrosis factor (TNF)-α, keratinocyte-derived chemokine (KC), and macrophage inflammatory protein (MIP)-2)], and oxidative stress (malondialdehyde (MDA) were measured 12 h after the experiment. Animal survival rates were calculated after 7 days. Means between groups were compared using linear regression models adjusted under the Bayesian approach. No significant difference was observed between control and study groups in serum concentrations of IL-6 (95% credible interval) (-0.35 to 0.44), TNF-α (-15.7 to 99.1), KC (-0.13 to 0.05), MIP-2 (-0.84 to 0.06), MDA (-1.25 to 2.53), or ALT (-6.6 to 11.5). Serum concentrations of CK-MB (-145.1 to -30.1), urea (-114.7 to -15.1), and creatinine (-1.14 to -0.01) were higher in the study group. Survival was similar in both groups (P=0.8). Therefore, the use of riboflavin in mice undergoing sepsis induced by CLP did not reduce inflammation, oxidative stress, organ dysfunction, or mortality compared with placebo.

Metabolic syndrome improves cardiovascular dysfunction and survival during cecal ligation and puncture-induced mild sepsis in mice

AIMS

Sepsis is a potentially fatal systemic inflammatory response and its underlying pathophysiology is still poorly understood. Studies suggest that obesity, a component of metabolic syndrome (MS), is associated with sepsis survival. Therefore, this study focused on investigating the influence of MS on mortality and cardiovascular dysfunction induced by sublethal cecal ligation and puncture (SL-CLP).

MAIN METHODS

Newborn Swiss mice received monosodium glutamate (MSG) (4 mg kg^-1 day^-1, s.c.) during the first 5 d of life for MS induction, while the control pups received equimolar saline solution. On the 75th day, SL-CLP was used to induce mild sepsis (M-CLP) in the MS (MS-M-CLP) and control (SAL-M-CLP) mice. The effect of MS on sepsis in mice was assessed by determining the survival rate and quantification of nitric oxide (NO) in the plasma, and associating this data with hematological and cardiovascular parameters.

KEY FINDINGS

MS improved the survival of septic mice, preventing impairment to hematological and cardiovascular parameters. In addition, MS attenuated plasmatic NO increase, which is a typical feature of sepsis.

SIGNIFICANCE

These findings provide new insights into the relationship between obesity and mild sepsis in mice, thus revealing an approach in favor of the "obesity paradox."

Higher blood urea nitrogen level is independently linked with the presence and severity of neonatal sepsis

BACKGROUND

Previous studies have demonstrated that blood urea nitrogen (BUN) is strongly associated with sepsis. However, no data are currently available regarding the association of BUN levels and neonatal sepsis. Thus, this study aimed to investigate the role of BUN in predicting the presence and severity of neonatal sepsis.

METHODS

In this study, we enrolled 925 neonates. Among them, 737 neonates were diagnosed with sepsis, including 426 neonates with severe sepsis. Neonates with hyperbilirubinemia (n = 188) served as controls. We collected complete clinical and laboratory data were collected. Multivariate logistic regression analysis was performed to identify the potential independent risk factor for neonatal sepsis. Receiver operating characteristic (ROC) curve analysis was used to evaluate the prediction accuracy of BUN in predicting neonatal sepsis. All statistical analyses were performed using the statistical package SPSS 24.0.

RESULTS

Neonates with sepsis and severe sepsis had a higher level of BUN. The prevalence of neonates with severe sepsis was dramatically increased according to BUN tertiles. Correlation analysis showed that BUN levels were positively correlated with the levels of infection marker procalcitonin (PCT) and high-sensitivity C-reactive protein (hsCRP). Multiple logistic regression analysis showed that BUN was an independent risk factor for the presence and severity of neonatal sepsis. ROC curve analysis showed that BUN had a well discriminatory power in predicting sepsis (area under curve (AUC) = 0.69, 95% CI, 0.66-0.74, p < .001) and severe sepsis (AUC = 0.72, 95% CI, 0.67-0.78, p < .001).

CONCLUSION

Higher BUN level is independently linked with the presence and severity of neonatal sepsis.

Assessment of Sumatriptan on Sepsis-Induced Kidney injury in the Cecal Ligation and Puncture Mice Model

Sepsis is a severe systemic inflammatory response with high mortality rate resulting from different microorganisms. Cytokines activation is essential for the immune response, but in painful conditions like sepsis, cytokines act as a double-edged sword and dysregulate immune response which is life-threatening owing to multiple organ dysfunction. The abnormality in 5-HT function is involved in pathological conditions like irritable bowel syndrome, inflammation, myocardial ischemia, itch and renal injury. Sumatriptan, a 5-HT_1B/1D agonist, has anti-inflammatory and anti-oxidative stress effects on animal models. This study was aimed to assess the effects of sumatriptan on kidney injury, the levels of pro-inflammatory cytokines and the percentage of survival in (CLP)-induced sepsis were examined.Cecal ligation and puncture (CLP) model was done on adult C57BL/6 male mice to induce Polymicrobial sepsis. Sumatriptan was injected intraperitoneally 1 h after the sepsis induction by CLP at doses of 0.1, 0.3, and 1 mg/kg in 3 treatment groups. To study the effect of sumatriptan on short-term survival, septic animals were detected 72 h after CLP. Serum levels of TNF-α, IL-1β, IL-6 and IL-10 were evaluated. To study sepsis-induced acute renal failure, kidney functional biomarkers and histopathological alterations were evaluated.Sumatriptan (0.3 mg/kg) administration significantly enhanced survival rate (P<0.01) compared to the CLP group. The beneficial effects of sumatriptan were related to a significant decrease in the pro-inflammatory cytokines and elevated level of IL-10. Sumatriptan presented protective effects on kidney biomarkers and histopathology assay.Anti-inflammatory effects of sumatriptan lead to decrease mortality rate and inflammatory cytokines in CLP induction sepsis in C57BL/6 mice.

A Kinetic Response Model for Standardized Regression Analyses of Inflammation-Triggered Hypothermic Body Temperature-Time Courses in Mice

LPS is frequently used to induce experimental endotoxic shock, representing a standard model of acute inflammation in mice. The resulting inflammatory response leads to hypothermia of the experimental animals, which in turn can be used as surrogate for the severity of systemic inflammation. Although increasingly applied as a humane endpoint in murine studies, differences between obtained temperature-time curves are typically evaluated at a single time point with t-tests or ANOVA analyses. We hypothesized that analyses of the entire temperature-time curves using a kinetic response model could fit the data, which show a temperature decrease followed by a tendency to return to normal temperature, and could increase the statistical power. Using temperature-time curves obtained from LPS stimulated mice, we derived a biologically motivated kinetic response model based on a differential equation. The kinetic model includes four parameters: (i) normal body temperature (T _n ), (ii) a coefficient related to the force of temperature autoregulation (r), (iii) damage strength (p ₀), and (iv) clearance rate (k). Kinetic modeling of temperature-time curves obtained from LPS stimulated mice is feasible and leads to a high goodness-of-fit. Here, modifying key enzymes of inflammatory cascades induced a dominant impact of genotypes on the damage strength and a weak impact on the clearance rate. Using a likelihood-ratio test to compare modeled curves of different experimental groups yields strongly enhanced statistical power compared to pairwise t-tests of single temperature time points. Taken together, the kinetic model presented in this study has several advantages compared to simple analysis of individual time points and therefore may be used as a standard method for assessing inflammation-triggered hypothermic response curves in mice.

Platelet P2Y 12 Receptor Deletion or Pharmacological Inhibition does not Protect Mice from Sepsis or Septic Shock

Introduction  Platelets are increasingly appreciated as key effectors during sepsis, raising the question of the usefulness of antiplatelet drugs to treat patients with sepsis.

Objective  Evaluate the potential contribution of the platelet P2Y ₁₂ receptor in the pathogenesis of polymicrobial-induced sepsis and septic shock in mice.

Methods  The effects of P2Y ₁₂ inhibition using clopidogrel treatment and of platelet-specific deletion of the P2Y ₁₂ receptor in mice were examined in two severity grades of cecal ligation and puncture (CLP) leading to mild sepsis or septic shock.

Results  Twenty hours after induction of the high grade CLP, clopidogrel- and vehicle-treated mice displayed a similar 30% decrease in mean arterial blood pressure (MAP) characteristic of shock. Septic shock-induced thrombocytopenia was not modified by clopidogrel treatment. Plasma concentrations of inflammatory cytokines and myeloperoxidase (MPO) were similarly increased in clopidogrel- and vehicle-treated mice, indicating comparable increase in systemic inflammation. Thrombin-antithrombin (TAT) complexes and the extent of organ damage were also similar. In mild-grade CLP, clopidogrel- and vehicle-treated mice did not display a significant decrease in MAP, while thrombocytopenia and plasma concentrations of TNFα, IL6, IL10, MPO, TAT and organ damage reached similar levels in both groups, although lower than those reached in the high grade CLP. Similarly, mice with platelet-specific deletion of the P2Y ₁₂ receptor were not protected from CLP-induced sepsis or septic shock.

Conclusion  The platelet P2Y ₁₂ receptor does not contribute to the pathogenesis of sepsis or septic shock in mice, suggesting that P2Y ₁₂ receptor antagonists may not be beneficial in patients with sepsis or septic shock.

Echinochrome pigment extracted from sea urchin suppress the bacterial activity, inflammation, nociception, and oxidative stress resulted in the inhibition of renal injury in septic rats

The current study aimed to evaluate the antibacterial, anti-inflammatory, analgesic, and renoprotective effects of echinochrome pigment extracted from sea urchin. The disk diffusion method was used for the antibacterial activity of echinochrome against four different bacterial strains; Salmonella typhimurium, Pseudomonas aeroginosa, Staphylococcus aureus, and Listeria monocytogenes. While, acetic acid-induced writhing, formalin-induced licking, and hot plate latency assays evaluate the analgesic activity. The biochemical and oxidative stress markers of kidneys, as well as the histopathological examination, were measured to evaluate the renoprotective activity of echinochrome for cecal ligation and puncture-induced renal injury in rats. Echinochrome pigment exhibited in vitro antibacterial activity against all aforementioned bacterial species besides a powerful anti-inflammatory impact in vitro by the effective stabilization of the RBCs membrane and in vivo by decrease levels of serum IL6 and TNF-α. What's more, echinochrome showed a notable analgesic efficacy as well as an enhancement of the kidney's biochemical markers, oxidative stress status, and histopathological screening. Ech attenuated cecal ligation and puncture-induced renal injury by improving renal biomarkers, suppressing reactive oxygen species propagation as well as its antibacterial, anti-inflammatory, and anti-nociceptive activities. PRACTICAL APPLICATIONS: Sea urchins are rich in pharmacologically important quinone pigments, specifically echinochrome. The current study aimed to evaluate the role of echinochrome as a renal protective remedy in sepsis and clarify its biological activities. Echinochrome exhibited antibacterial activity in vitro against Salmonella typhimurium, Pseudomonas aeroginosa, Staphylococcus aureus, and Listeria monocytogenes. Our results revealed that echinochrome protects the kidney against damage caused by sepsis in rats. Echinochrome can use in the treatment of sepsis as an antibacterial, anti-inflammatory, and antioxidant agent.

New Approaches to Identify Sepsis Biomarkers: The Importance of Model and Sample Source for Mass Spectrometry

Septic shock is a systemic inflammatory response syndrome associated with circulatory failure leading to organ failure with a 40% mortality rate. Early diagnosis and prognosis of septic shock are necessary for specific and timely treatment. However, no predictive biomarker is available. In recent years, improvements in proteomics-based mass spectrometry have improved the detection of such biomarkers. This approach can be performed on different samples such as tissue or biological fluids. Working directly from human samples is complicated owing to interindividual variability. Indeed, patients are admitted at different stages of disease development and with signs of varying severity from one patient to another. All of these elements interfere with the identification of early, sensitive, and specific septic shock biomarkers. For these reasons, animal models of sepsis, although imperfect, are used to control the kinetics of the development of the pathology and to standardise experimentation, facilitating the identification of potential biomarkers. These elements underline the importance of the choice of animal model used and the sample to be studied during preclinical studies. The aim of this review is to discuss the relevance of different approaches to enable the identification of biomarkers that could indirectly be relevant to the clinical setting.

TICAM2-related pathway mediates neutrophil exhaustion

Pathogenic inflammation and immune suppression are the cardinal features that underlie the pathogenesis of severe systemic inflammatory syndrome and sepsis. Neutrophil exhaustion may play a key role during the establishment of pathogenic inflammation and immune suppression through elevated expression of inflammatory adhesion molecules such as ICAM1 and CD11b as well as immune-suppressors such as PD-L1. However, the mechanism of neutrophil exhaustion is not well understood. We demonstrated that murine primary neutrophils cultured in vitro with the prolonged lipopolysaccharides (LPS) stimulation can effectively develop an exhaustive phenotype resembling human septic neutrophils with elevated expression of ICAM1, CD11b, PD-L1 as well as enhanced swarming and aggregation. Mechanistically, we observed that TICAM2 is involved in the generation of neutrophil exhaustion, as TICAM2 deficient neutrophils have the decreased expression of ICAM1, CD11b, PD-L1, and the reduced aggregation following the prolonged LPS challenge as compared to wild type (WT) neutrophils. LPS drives neutrophil exhaustion through TICAM2 mediated activation of Src family kinases (SFK) and STAT1, as the application of SFK inhibitor Dasatinib blocks neutrophil exhaustion triggered by the prolonged LPS challenge. Functionally, TICAM2 deficient mice were protected from developing severe systemic inflammation and multi-organ injury following the chemical-induced mucosal damage. Together, our data defined a key role of TICAM2 in facilitating neutrophil exhaustion and that targeting TICAM2 may be a potential approach to treating the severe systemic inflammation.

Mechanisms Underlying Potential Therapeutic Approaches for COVID-19

Coronavirus disease (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is a betacoronavirus, and is associated with cytokine storm inflammation and lung injury, leading to respiratory distress. The transmission of the virus is mediated by human contact. To control and prevent the spread of this virus, the majority of people worldwide are facing quarantine; patients are being subjected to non-specific treatments under isolation. To prevent and stop the COVID-19 pandemic, several clinical trials are in the pipeline. The current clinical trials either target the intracellular replication and spread of the virus or the cytokine storm inflammation seen in COVID-19 cases during the later stages of the disease. Since both targeting strategies are different, the window drug administration plays a crucial role in the efficacy of the treatment. Here, we review the mechanism underlying SARS-CoV-2 cell infection and potential future therapeutic approaches.

Apoptotic cell therapy for cytokine storm associated with acute severe sepsis

Sepsis has no proven pharmacologic treatment other than appropriate antibiotic agents, fluids, vasopressors as needed, and possibly corticosteroids. It is generally initiated mainly by the simultaneous recognition by various components of the innate immune system of either pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). In the current study, we employed the murine cecal ligation and puncture (CLP) model for sepsis to evaluate the effect of post-CLP infusion of apoptotic cells (Allocetra-OTS) on a CLP severe sepsis model. Cardiovascular evaluation, acute kidney injury (AKI), acute liver injury (ALI), and hematological and metabolic function were evaluated. Cytokine and chemokine profiles were measured by Multiplex ELISA and mitochondrial function, and glycolysis by Seahorse. The Murine Sepsis Score (MSS) was used for disease severity definition. CLP mice had low blood pressure, poor cardiac output, and lung dysfunction, as well as AKI, ALI, and thrombocytopenia, which correlated with the MSS and corresponded to a cytokine/chemokine storm. Apoptotic cell administration markedly improved the cytokine and chemokine storm and restored the impaired mitochondrial and glycolytic function in white blood cells leading to increased survival, from 6 to 60% (P < 0.0001), together with a significant improvement in organ dysfunction. We conclude that the deleterious immune response in CLP-induced sepsis can be successfully modified by apoptotic cell infusion.

Intraperitoneal Phototherapy Suppresses Inflammatory Reactions in a Surgical Model of Peritonitis

BACKGROUND

Standard treatment for diffuse peritonitis due to colorectal perforation may be insufficient to suppress inflammatory reaction in sepsis. Thus, developing new treatments is important. This study aimed to examine whether intraperitoneal irradiation by artificial sunlight suppresses inflammatory reaction in a lipopolysaccharide (LPS)-induced peritonitis model after surgical treatments.

MATERIALS AND METHODS

Mice were divided into naive, nontreatment (NT), and phototherapy (PT) groups. In the latter two groups, LPS was intraperitoneally administered to induce peritonitis and removed by intraperitoneal lavage after laparotomy. The PT group was irradiated with artificial sunlight intraperitoneally. We evaluated the local and systemic inflammatory reactions. Murine macrophages were irradiated with artificial sunlight after stimulation by LPS, and cell viability and expression of tumor necrotizing factor-α (TNF-α) were evaluated.

RESULTS

As a local inflammatory reaction, the whole cell count, the expression of interleukin-6 and TNF-α in the intra-abdominal fluid, and the peritoneal thickness were significantly lower in the PT group than in the NT group. As a systematic inflammatory reaction, the expression of serum TNF-α, granulocyte macrophage colony-stimulating factor, monocyte chemotactic protein-1, macrophage inflammatory protein (MIP)-1α, and MIP-1β were significantly lower in the PT group than in the NT group. Irradiation by artificial sunlight suppressed the expression of TNF-α in murine macrophages without affecting cell viability.

CONCLUSIONS

Intraperitoneal irradiation by artificial sunlight could suppress local and systemic inflammatory reactions in the LPS-induced peritonitis murine model. These effects may be associated with macrophage immune responses.

l-theanine alleviates liver and kidney dysfunction in septic rats induced by cecal ligation and puncture

AIMS

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response against infection that triggers systemic inflammatory response syndrome. l-theanine (LT), a glutamate derivative, is a non-protein amino acid derived from tea (Camellia sinensis), and a valuable nutraceutical product used as an additive in the food industry. This study we aimed to investigate whether LT would exert any therapeutic effect on liver and kidney tissues in Sprague Dawley rats with sepsis induced with cecal ligation and puncture (CLP).

MAIN METHODS

Rats were divided into four groups; sham, CLP, CLP+LT1 (2x250 mg/kg) and CLP+LT2 (2 × 750 mg/kg). Liver and kidney tissues were subjected to histopathological examination. Apoptotic index percentages (AI%) were examined using the TUNEL method. The oxidized glutathione to total glutathione (GSSG/TGSH) ratio (as a marker of oxidative stress, levels of caspase-3 (a marker of apoptosis), glutathione peroxidase (GPx) and glutathione S-transferase (GST) (as antioxidant enzymes), inducible nitric oxide synthase (iNOS) and the tumor necrosis factor-α to Interleukin-10 ratio (TNF-α/IL-10) (as markers of inflammation) were investigated using commercial kits. Levels of malondialdehyde (MDA) (a marker of oxidative stress) were determined spectrophotometrically.

KEY FINDINGS

A high dose of LT exhibited more significant effects in reducing oxidative stress, inflammation and apoptosis than a low dose of LT in liver and kidney tissues with CLP-induced sepsis (p < 0.05).

SIGNIFICANCE

Our results indicated that LT significantly and dose-dependently inhibited sepsis induced liver and kidney injury. This effect may be attributed to the antioxidant, anti-inflammatory, and anti-apoptotic activities of LT.

Evaluation of 2 Rat Models for Sepsis Developed by Improved Cecal Ligation/Puncture or Feces Intraperitoneal-Injection

Background

The aim of this study was to evaluate the clinical characteristics of 2 rat models of sepsis for improved cecal ligation/puncture (CLP) and feces intraperitoneal-injection (FIP), including systemic inflammation, organ dysfunction, and blood coagulation.

Material/Methods

Sixty-two male SD rats were randomly divided into 3 groups: a normal control group (NC, n=6), a CLP group (n=28), and a FIP group (n=28). Ten rats each in the CLP and FIP groups were observed for 72-h mortality rate. The remaining 18 rats in each group were divided into 3 subgroups (n=6) according to their post-operation period (6, 12, and 24 h). Abdominal arterial blood was collected to determine the lactic acid (Lac) concentration, prothrombin time (PT), active partial prothrombin time (APTT), plasmic interleukin-6 (IL-6) level, and cardiac troponin (cTnI) level. The intestines, lung, and heart were collected for pathological examination.

Results

The 72-h mortality rates in the CLP and FIP groups were 60% and 100%, respectively. The Lac level in both groups was significantly elevated at 6, 12, and 24 h after modeling. Compared with the NC group, PT in the CLP and FIP groups was prolonged at 12 and 24 h, and APTT was significantly prolonged at 6 h. IL-6 levels in the CLP and FIP groups peaked at 6 h. The cTnI level in the FIP group was significantly higher at 12 h after modeling compared with the NC group. The intestines, lung, and heart were pathologically damaged at 6 h, and this damage worsened over time.

Conclusions

Both modeling methods induced sepsis in rats and closely mimicked the clinical conditions, but FIP was easier to establish and was more suitable for standardization.

Impact of Intermittent Hypoxia on Sepsis Outcomes in a Murine Model

Sleep apnea has been associated with a variety of diseases, but its impact on sepsis outcome remains unclear. This study investigated the effect of intermittent hypoxia [IH]–the principal feature of sleep apnea–on murine sepsis. 5-week-old male C57BL6 mice were assigned to groups receiving severe IH (O2 fluctuating from room air to an O2 nadir of 5.7% with a cycle length of 90 seconds), mild IH (room air to 12%, 4 minutes/cycle), or room air for 3 weeks. Sepsis was induced by cecal ligation and puncture and survival was monitored. Sepsis severity was evaluated by murine sepsis scores, blood bacterial load, plasma tumor necrosis factor-α [TNF-α]/interleukin-6 [IL-6] levels and histopathology of vital organs. Compared with normoxic controls, mice subjected to severe IH had earlier mortality, a lower leukocyte count, higher blood bacterial load, higher plasma TNF-α and IL-6 levels, more severe inflammatory changes in the lung, spleen and small intestine. Mice subjected to mild IH did not differ from normoxic controls, except a higher IL-6 level after sepsis induced. The adverse impact of severe IH was reversed following a 10-day normoxic recovery. In conclusion, severe IH, not mild IH, contributed to poorer outcomes in a murine sepsis model.

Prophylactic simvastatin treatment modulates the immune response and increases survival of mice following induction of lethal sepsis

Objective

To investigate whether and how simvastatin mediates protection from lethal sepsis, using a mouse model.

Methods

Sixty C57BL/6 mice were selected and divided into three groups (“control,” “model,” and “observation”; n = 20 mice per group). Mice in the model and observation groups underwent cecal ligation and puncture; mice in the observation group received simvastatin. After 24 hours of induced sepsis, serum concentrations of IL-6, TNF-α, IL-1, and IL-10 were measured by ELISA. Serum malondialdehyde (MDA) concentrations and serum superoxide dismutase (SOD) activities were quantified by radioimmunoassay.

Results

The mean duration of survival of mice in the observation group was significantly longer than that of the model group. The serum concentrations of IL-6, TNF-α, IL-1, IL-10, and MDA were significantly higher in the observation group than in the control group. Serum SOD activities were significantly lower in the observation group than in the control group.

Conclusions

Simvastatin can alleviate symptoms of sepsis in mice and improve their rates of survival. The mechanism of action of simvastatin may be mediated by inhibition of the systemic inflammatory response and oxidative stress.

Differential Roles of Dendritic Cells in Expanding CD4 T Cells in Sepsis

Sepsis is a systemically dysregulated inflammatory syndrome, in which dendritic cells (DCs) play a critical role in coordinating aberrant immunity. The aim of this study is to shed light on the differential roles played by systemic versus mucosal DCs in regulating immune responses in sepsis. We identified a differential impact of the systemic and mucosal DCs on proliferating allogenic CD4 T cells in a mouse model of sepsis. Despite the fact that the frequency of CD4 T cells was reduced in septic mice, septic mesenteric lymph node (MLN) DCs proved superior to septic spleen (SP) DCs in expanding allogeneic CD4 T cells. Moreover, septic MLN DCs markedly augmented the surface expression of MHC class II and CD40, as well as the messaging of interleukin-1β (IL-1β). Interestingly, IL-1β-treated CD4 T cells expanded in a dose-dependent manner, suggesting that this cytokine acts as a key mediator of MLN DCs in promoting septic inflammation. Thus, mucosal and systemic DCs were found to be functionally different in the way CD4 T cells respond during sepsis. Our study provides a molecular basis for DC activity, which can be differential in nature depending on location, whereby it induces septic inflammation or immune-paralysis.