Sepsis: frontiers in supportive care, organisation and research

TR4 worsen urosepsis by regulating GSDMD

BACKGROUND

Urosepsis is a life-threatening organ disease in which pathogenic microorganisms in the urine enter the blood through the vessels, causing an imbalance in the immune response to infection. The aim of this study was to elucidate the role of testicular orphan receptor 4 (TR4) in urosepsis.

METHODS

The role of TR4 in the progression and prognosis of urosepsis was confirmed by analyzing data from online databases and clinical human samples. To mimic urosepsis, we injected E. coli bacteria into the renal pelvis of mice to create a urosepsis model. Hematoxylin and eosin staining was used to observe histopathological changes in urosepsis. The effects of the upregulation or downregulation of TR4 on macrophage pyroptosis were verified in vitro. Chromatin immunoprecipitation assay was used to verify the effect of TR4 on Gasdermin D (GSDMD) transcription.

RESULTS

TR4 was more highly expressed in the nonsurviving group than in the surviving group. Furthermore, overexpressing TR4 promoted inflammatory cytokine expression, and knocking down TR4 attenuated inflammatory cytokine expression. Mechanistically, TR4 promoted pyroptosis by regulating the expression of GSDMD in urosepsis. Furthermore, we also found that TR4 knockdown protected mice from urosepsis induced by the E. coli.

CONCLUSIONS

TR4 functions as a key regulator of urosepsis by mediating pyroptosis, which regulates GSDMD expression. Targeting TR4 may be a potential strategy for urosepsis treatment.

The Clinical Value of Comprehensive Nursing Intervention in Preventing Severe Lymphopenia and Improving the Survival Rate Among Patients with Sepsis

Background

Intensive care unit (ICU) patients with sepsis who experience severe lymphopenia are at a higher risk of mortality, and they serve as a more accurate indicator of bacteremia compared to traditional infection markers.

Aim

Our study aimed to examine the influence of severe lymphopenia on ICU mortality and outcomes in sepsis patients, while also evaluating the clinical significance of comprehensive nursing intervention in preventing severe lymphopenia.

Methods

Patients with sepsis in the ICU at our hospital between January 2015 and January 2021 were split into a control group and a test group.The control group received regular nursing care, while the test group was provided with comprehensive nursing care in addition to the control group. The results encompassed mortality rates of 28 days, mortality rates of 1 year, and lengths of stay in the ICU.

Results

Our attention was directed towards day 4 absolute lymphocyte counts, taking into account the receiver operating characteristic (ROC) outcome. Patients with severe lymphopenia were older, more patients with 2 above comorbidities, higher co-infection rates and SOFA score. In addition, patients with severe lymphopenia required longer days stay in ICU (P<0.001), and presented with higher 28-day mortality (P=0.038) and 1-year mortality (P=0.004). Patients in control group have a higher incidence of severe lymphopenia (P=0.006), 28-day mortality (P=0.015) and 1-year mortality (P=0.019) compared with the test group.

Conclusion

Comprehensive nursing intervention can prevent the occurrence of severe lymphopenia, improve patients satisfaction and reduce mortality.

Neutrophil extracellular traps contribute to immunothrombosis formation via the STING pathway in sepsis-associated lung injury

Neutrophil extracellular traps (NETs) are involved in the activation and dysfunction of multiple overlapping and interacting pathways, including the immune response to injury, inflammation, and coagulation, which contribute to the pathogenesis of sepsis-induced acute lung injury (SI-ALI). However, how NETs mediate the relationship between inflammation and coagulation has not been fully clarified. Here, we found that NETs, through stimulator of interferon genes (STING) activation, induced endothelial cell damage with abundant production of tissue factor (TF), which magnified the dysregulation between inflammatory and coagulant responses and resulted in poor prognosis of SI-ALI model mice. Disruption of NETs and inhibition of STING improved the outcomes of septic mice and reduced the inflammatory response and coagulation. Furthermore, Toll-like receptor 2 (TLR2) on the surface of endothelial cells was involved in the interaction between NETs and the STING pathway. Collectively, these findings demonstrate that NETs activate the coagulant cascade in endothelial cells in a STING-dependent manner in the development of SI-ALI.

Less Severe Polymicrobial Sepsis in Conditional mgmt-Deleted Mice Using LysM-Cre System, Impacts of DNA Methylation and MGMT Inhibitor in Sepsis

The O6-methylguanine-DNA methyltransferase (MGMT) is a DNA suicide repair enzyme that might be important during sepsis but has never been explored. Then, the proteomic analysis of lipopolysaccharide (LPS)-stimulated wild-type (WT) macrophages increased proteasome proteins and reduced oxidative phosphorylation proteins compared with control, possibly related to cell injury. With LPS stimulation, mgmt null (mgmt^flox/flox; LysM-Cre^cre/-) macrophages demonstrated less profound inflammation; supernatant cytokines (TNF-α, IL-6, and IL-10) and pro-inflammatory genes (iNOS and IL-1β), with higher DNA break (phosphohistone H2AX) and cell-free DNA, but not malondialdehyde (the oxidative stress), compared with the littermate control (mgmt^flox/flox; LysM-Cre^-/-). In parallel, mgmt null mice (MGMT loss only in the myeloid cells) demonstrated less severe sepsis in the cecal ligation and puncture (CLP) model (with antibiotics), as indicated by survival and other parameters compared with sepsis in the littermate control. The mgmt null protective effect was lost in CLP mice without antibiotics, highlighting the importance of microbial control during sepsis immune modulation. However, an MGMT inhibitor in CLP with antibiotics in WT mice attenuated serum cytokines but not mortality, requiring further studies. In conclusion, an absence of mgmt in macrophages resulted in less severe CLP sepsis, implying a possible influence of guanine DNA methylation and repair in macrophages during sepsis.

Less Severe Lipopolysaccharide-Induced Inflammation in Conditional mgmt-Deleted Mice with LysM-Cre System: The Loss of DNA Repair in Macrophages

Despite the known influence of DNA methylation from lipopolysaccharide (LPS) activation, data on the O6-methylguanine-DNA methyltransferase (MGMT, a DNA suicide repair enzyme) in macrophages is still lacking. The transcriptomic profiling of epigenetic enzymes from wild-type macrophages after single and double LPS stimulation, representing acute inflammation and LPS tolerance, respectively, was performed. Small interfering RNA (siRNA) silencing of mgmt in the macrophage cell line (RAW264.7) and mgmt null (mgmt^flox/flox; LysM-Cre^cre/-) macrophages demonstrated lower secretion of TNF-α and IL-6 and lower expression of pro-inflammatory genes (iNOS and IL-1β) compared with the control. Macrophage injury after a single LPS dose and LPS tolerance was demonstrated by reduced cell viability and increased oxidative stress (dihydroethidium) compared with the activated macrophages from littermate control mice (mgmt^flox/flox; LysM-Cre^-/-). Additionally, a single LPS dose and LPS tolerance also caused mitochondrial toxicity, as indicated by reduced maximal respiratory capacity (extracellular flux analysis) in the macrophages of both mgmt null and control mice. However, LPS upregulated mgmt only in LPS-tolerant macrophages but not after the single LPS stimulation. In mice, the mgmt null group demonstrated lower serum TNF-α, IL-6, and IL-10 than control mice after either single or double LPS stimulation. Suppressed cytokine production resulting from an absence of mgmt in macrophages caused less severe LPS-induced inflammation but might worsen LPS tolerance.

Less Severe Sepsis in Cecal Ligation and Puncture Models with and without Lipopolysaccharide in Mice with Conditional Ezh2-Deleted Macrophages (LysM-Cre System)

Despite a previous report on less inflammatory responses in mice with an absence of the enhancer of zeste homologue 2 (Ezh2), a histone lysine methyltransferase of epigenetic regulation, using a lipopolysaccharide (LPS) injection model, proteomic analysis and cecal ligation and puncture (CLP), a sepsis model that more resembles human conditions was devised. As such, analysis of cellular and secreted protein (proteome and secretome) after a single LPS activation and LPS tolerance in macrophages from Ezh2 null (Ezh2^flox/flox; LysM-Cre^cre/-) mice (Ezh2 null) and the littermate control mice (Ezh2^fl/fl; LysM-Cre^-/-) (Ezh2 control) compared with the unstimulated cells from each group indicated fewer activities in Ezh2 null macrophages, especially by the volcano plot analysis. Indeed, supernatant IL-1β and expression of genes in pro-inflammatory M1 macrophage polarization (IL-1β and iNOS), TNF-α, and NF-κB (a transcription factor) were lower in Ezh2 null macrophages compared with the control. In LPS tolerance, downregulated NF-κB compared with the control was also demonstrated in Ezh2 null cells. In CLP sepsis mice, those with CLP alone and CLP at 2 days after twice receiving LPS injection, representing sepsis and sepsis after endotoxemia, respectively, symptoms were less severe in Ezh2 null mice, as indicated by survival analysis and other biomarkers. However, the Ezh2 inhibitor improved survival only in CLP, but not LPS with CLP. In conclusion, an absence of Ezh2 in macrophages resulted in less severe sepsis, and the use of an Ezh2 inhibitor might be beneficial in sepsis.

The role of nanotechnology-based approaches for clinical infectious diseases and public health

Given the high incidence of infection and the growing resistance of bacterial and viral infections to the traditional antiseptic, the need for novel antiseptics is critical. Therefore, novel approaches are urgently required to reduce the activity of bacterial and viral infections. Nanotechnology is increasingly being exploited for medical purposes and is of significant interest in eliminating or limiting the activity of various pathogens. Due to the increased surface-to-volume ratio of a given mass of particles, the antimicrobial properties of some naturally occurring antibacterial materials, such as zinc and silver, increase as particle size decreases into the nanometer regime. However, the physical structure of a nanoparticle and the way it interacts with and penetrates the bacteria also appear to provide unique bactericidal mechanisms. To measure the efficacy of nanoparticles (diameter 100 nm) as antimicrobial agents, it is necessary to comprehend the range of approaches for evaluating the viability of bacteria; each of them has its advantages and disadvantages. The nanotechnology-based disinfectants and sensors for SARS-CoV-2 provide a roadmap for creating more effective sensors and disinfectants for detecting and preventing coronaviruses and other infections. Moreover, there is an increasing role of nanotechnology-based approaches in various infections, including wound healing and related infection, nosocomial infections, and various bacterial infections. To meet the demand for patient care, nanotechnology-based disinfectants need to be further advanced with optimum approaches. Herein, we review the current burden of infectious diseases with a focus on SARS-CoV-2 and bacterial infection that significantly burdens developed healthcare systems and small healthcare communities. We then highlight how nanotechnology could aid in improving existing treatment modalities and diagnosis of those infectious agents. Finally, we conclude the current development and future perspective of nanotechnology for combating infectious diseases. The overall goal is to update healthcare providers on the existing role and future of nanotechnology in tackling those common infectious diseases.

The Regulatory Roles of Ezh2 in Response to Lipopolysaccharide (LPS) in Macrophages and Mice with Conditional Ezh2 Deletion with LysM-Cre System

The responses of macrophages to lipopolysaccharide (LPS) might determine the direction of clinical manifestations of sepsis, which is the immune response against severe infection. Meanwhile, the enhancer of zeste homologue 2 (Ezh2), a histone lysine methyltransferase of epigenetic regulation, might interfere with LPS response. Transcriptomic analysis on LPS-activated wild-type macrophages demonstrated an alteration of several epigenetic enzymes. Although the Ezh2-silencing macrophages (RAW264.7), using small interfering RNA (siRNA), indicated a non-different response to the control cells after a single LPS stimulation, the Ezh2-reducing cells demonstrated a less severe LPS tolerance, after two LPS stimulations, as determined by the higher supernatant TNF-α. With a single LPS stimulation, Ezh2 null (Ezh2flox/flox; LysM-Crecre/−) macrophages demonstrated lower supernatant TNF-α than Ezh2 control (Ezh2fl/fl; LysM-Cre−/−), perhaps due to an upregulation of Socs3, which is a suppressor of cytokine signaling 3, due to the loss of the Ezh2 gene. In LPS tolerance, Ezh2 null macrophages indicated higher supernatant TNF-α and IL-6 than the control, supporting an impact of the loss of the Ezh2 inhibitory gene. In parallel, Ezh2 null mice demonstrated lower serum TNF-α and IL-6 than the control mice after an LPS injection, indicating a less severe LPS-induced hyper-inflammation in Ezh2 null mice. On the other hand, there were similar serum cytokines after LPS tolerance and the non-reduction of serum cytokines after the second dose of LPS, indicating less severe LPS tolerance in Ezh2 null mice compared with control mice. In conclusion, an absence of Ezh2 in macrophages resulted in less severe LPS-induced inflammation, as indicated by low serum cytokines, with less severe LPS tolerance, as demonstrated by higher cytokine production, partly through the upregulated Socs3.

Lipopolysaccharide Tolerance Enhances Murine Norovirus Reactivation: An Impact of Macrophages Mainly Evaluated by Proteomic Analysis

Because of endotoxemia during sepsis (a severe life-threatening infection), lipopolysaccharide (LPS) tolerance (the reduced responses to the repeated LPS stimulation) might be one of the causes of sepsis-induced immune exhaustion (the increased susceptibility to secondary infection and/or viral reactivation). In LPS tolerance macrophage (twice-stimulated LPS, LPS/LPS) compared with a single LPS stimulation (N/LPS), there was (i) reduced energy of the cell in both glycolysis and mitochondrial activities (extracellular flux analysis), (ii) decreased abundance of the following proteins (proteomic analysis): (a) complex I and II of the mitochondrial electron transport chain, (b) most of the glycolysis enzymes, (c) anti-viral responses with Myxovirus resistance protein 1 (Mx1) and Ubiquitin-like protein ISG15 (Isg15), (d) antigen presentation pathways, and (iii) the down-regulated anti-viral genes, such as Mx1 and Isg15 (polymerase chain reaction). To test the correlation between LPS tolerance and viral reactivation, asymptomatic mice with and without murine norovirus (MNV) infection as determined in feces were tested. In MNV-positive mice, MNV abundance in the cecum, but not in feces, of LPS/LPS mice was higher than that in N/LPS and control groups, while MNV abundance of N/LPS and control were similar. Additionally, the down-regulated Mx1 and Isg15 were also demonstrated in the cecum, liver, and spleen in LPS/LPS-activated mice, regardless of MNV infection, while N/LPS more prominently upregulated these genes in the cecum of MNV-positive mice compared with the MNV-negative group. In conclusion, defects in anti-viral responses after LPS tolerance, perhaps through the reduced energy status of macrophages, might partly be responsible for the viral reactivation. More studies on patients are of interest.

Factors associated with the decision to administer β-lactams via prolonged infusion in patients with sepsis: a prospective observational cohort study

OBJECTIVE

β-lactams are the most widely used antibiotics in sepsis. We aimed to explore the factors that drive physicians to choose prolonged infusion (PI) of β-lactams in septic patients.

METHODS

This prospective observational national cohort study was conducted in 40 ICUs at the teaching hospitals of 31 provinces in China between August 20, 2021 and September 20, 2021.

RESULTS

Of the 441 enrolled patients, 265 (60.09%) received PI therapy. Multivariate analysis showed that multidrug-resistant bacterial infection and septic shock were independent factors associated with PI. However, our data showed that the survival benefit of PI use was evident in subgroups with less severe sepsis, including those with lower Charlson comorbidity index values (<2), those without septic shock, and those with lower acute physiology and chronic health evaluation II scores (<15). Univariate and multivariate Cox regression indicated that PI was an independent protective factor of 28d mortality, even after adjusting the variables associated with disease severity.

CONCLUSIONS

PI for administering β-lactams was not a commonly applied strategy in sepsis and was more likely to be used in severely ill patients. However, PI had a survival benefit independent of disease severity.

Omega-3 fatty acids impair miR-1-3p-dependent Notch3 down-regulation and alleviate sepsis-induced intestinal injury

Background

Sepsis is a troublesome syndrome that can cause intestinal injury and even high mortality rates. Omega-3 fatty acids (FAs) are known to protect against intestinal damage. Accordingly, the current study set out to explore if omega-3 FAs could affect sepsis-induced intestinal injury with the involvement of the microRNA (miR)-1-3p/Notch3-Smad axis.

Methods

First, cecal ligation and perforation (CLP) was performed to establish septic mouse models in C57BL/6J mice, and mouse intestinal epithelial MODE-K cells were induced by lipopolysaccharide (LPS) to establish sepsis cell models. The CLP-induced septic mice or LPS-exposed cells were subjected to treatment with Omega-3 FAs and activin (Smad signaling activator), miR-1-3p inhibitor and over-expressed/short hairpin RNA (oe-/sh)-Notch3 to explore their roles in inflammation, intestinal oxidative stress and cell apoptosis. A dual-luciferase reporter gene assay was further performed to verify the regulatory relationship between miR-1-3p and Notch3.

Results

Omega-3 FAs inhibited CLP-induced intestinal injury and ameliorated LPS-induced intestinal epithelial cell injury by down-regulating miR-1-3p, as evidenced by decreased levels of tumor necrosis factor-α, interleukin-1β (IL-1β) and IL-6, in addition to diminished levels of reactive oxygen species, malondialdehyde levels and superoxide dismutase activity. Furthermore, miR-1-3p could down-regulate Notch3, which inactivated the Smad pathway.

Conclusion

Collectively, our findings indicated that omega-3 FAs elevate the expression of Notch3 by down-regulating miR-1-3p, and then blocking the Smad pathway to alleviate intestinal epithelial inflammation and oxidative stress injury caused by sepsis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00425-w.

Intraperitoneal supplementation of iron alleviates dextran sodium sulfate-induced colitis by enhancing intestinal barrier function

Iron supplementation is necessary for the treatment of anemia, one of the most frequent complications in inflammatory bowel disease (IBD). However, oral iron supplementation leads to an exacerbation of intestinal inflammation. Gut barrier plays a key role in the pathogenesis of IBD. The aim of this study was to characterize the interrelationship between systemic iron, intestinal barrier and the development of intestinal inflammation in a dextran sulfate sodium (DSS) induced experimental colitis mice model. We found that DSS-treated mice developed severe inflammation of colon, but became much healthy when intraperitoneal injection with iron. Iron supplementation alleviated colonic and systemic inflammation by lower histological scores, restorative morphology of colonic villi, and reduced expression of pro-inflammatory cytokines. Moreover, intraperitoneal supplementation of iron enhanced intestinal barrier function by upregulating the colonic expressions of tight junction proteins, restoring intestinal immune homeostasis by regulating immune cell infiltration and T lymphocyte subsets, and increasing mucous secretion of goblet cells in the colon. High-throughput sequencing of fecal 16 S rRNA showed that iron injection significantly increased the relative abundance of Bacteroidetes, which was suppressed in the gut microbiota of DSS-induced colitis mice. These results provided evidences supporting the protective effects of systemic iron repletion by intraperitoneal injection of iron on intestinal barrier functions. The finding highlights a novel approach for the treatment of IBD with iron injection therapy.

Functional delivery of lncRNA TUG1 by endothelial progenitor cells derived extracellular vesicles confers anti-inflammatory macrophage polarization in sepsis via impairing miR-9-5p-targeted SIRT1 inhibition

The delivery of biomolecules by extracellular vesicles (EVs) derived from endothelial progenitor cells (EPCs) has been proven to ameliorate sepsis, yet the therapeutic mechanism remains to be elucidated. Taurine upregulated gene 1 (TUG1) is a long noncoding RNA (lncRNA) that is downregulated in sepsis. The current study was designed to explore the role of EPCs derived EVs transmitting TUG1 in macrophage polarization and macrophage-mediated inflammation in a cecal ligation and puncture (CLP)-induced sepsis mouse model. TUG1 was underexpressed in CLP-induced sepsis, and its reexpression induced anti-inflammatory macrophage polarization and suppressed macrophage-medicated inflammatory injury to the pulmonary vascular endothelium. EPCs derived EVs transmitted TUG1 to promote M2 macrophage polarization. Luciferase, RIP, and RNA pull-down assays showed that TUG1 could competitively bind to microRNA-9-5p (miR-9-5p) to upregulate the expression of sirtuin 1 (SIRT1). Furthermore, EPCs derived EVs transmitted TUG1 to promote M2 macrophage polarization through the impairment of miR-9-5p-dependent SIRT1 inhibition. Finally, EPCs derived EVs carrying TUG1 were verified to ameliorate sepsis-induced organ damage in the murine model. In summary, EPCs derived EVs transmit TUG1 to attenuate sepsis via macrophage M2 polarization. This study also highlights the proinflammatory mechanism associated with miR-9-5p-mediated inhibition of SIRT1, which contributes to a more comprehensive understanding of the pathogenesis of sepsis.

Prediction of 90-Day Mortality among Sepsis Patients Based on a Nomogram Integrating Diverse Clinical Indices

Background

Sepsis is prevalent among intensive care units and is a frequent cause of death. Several studies have identified individual risk factors or potential predictors of sepsis-associated mortality, without defining an integrated predictive model. The present work was aimed at defining a nomogram for reliably predicting mortality.

Methods

We carried out a retrospective, single-center study based on 231 patients with sepsis who were admitted to our intensive care unit between May 2018 and October 2020. Patients were randomly split into training and validation cohorts. In the training cohort, multivariate logistic regression and a stepwise algorithm were performed to identify risk factors, which were then integrated into a predictive nomogram. Nomogram performance was assessed against the training and validation cohorts based on the area under receiver operating characteristic curves (AUC), calibration plots, and decision curve analysis.

Results

Among the 161 patients in the training cohort and 70 patients in the validation cohort, 90-day mortality was 31.6%. Older age and higher values for the international normalized ratio, lactate level, and thrombomodulin level were associated with greater risk of 90-day mortality. The nomogram showed an AUC of 0.810 (95% CI 0.739 to 0.881) in the training cohort and 0.813 (95% CI 0.708 to 0.917) in the validation cohort. The nomogram also performed well based on the calibration curve and decision curve analysis.

Conclusion

This nomogram may help identify sepsis patients at elevated risk of 90-day mortality, which may help clinicians allocate resources appropriately to improve patient outcomes.

Selective inhibition of PKCβ2 improves Caveolin-3/eNOS signaling and attenuates lipopolysaccharide-induced injury by inhibiting autophagy in H9C2 cardiomyocytes

Lipopolysaccharide (LPS)-induced autophagy is involved in sepsis-associated myocardial injury with increased PKCβ2 activation. We previously found hyperglycemia-induced PKCβ2 activation impaired the expression of caveolin-3 (Cav-3), the dominant isoform to form cardiomyocytes caveolae which modulate eNOS signaling to confer cardioprotection in diabetes. However, little is known about the roles of PKCβ2 in autophagy and Cav-3/eNOS signaling in cardiomyocytes during LPS exposure. We hypothesize LPS-induced PKCβ2 activation promotes autophagy and impairs Cav-3/eNOS signaling in LPS-treated cardiomyocytes. H9C2 cardiomyocytes were treated with LPS (10 µg/mL) in the presence or absence of PKCβ2 inhibitor CGP53353 (CGP, 1 µM) or autophagy inhibitor 3-methyladenine (3-MA, 10 µM). LPS stimulation induced cytotoxicity overtime in H9C2 cardiomyocytes, accompanied with excessive PKCβ2 activation. Selective inhibition of PKCβ2 with CGP significantly reduced LPS-induced cytotoxicity and autophagy (measured by LC-3II, Beclin-1, p62 and autophagic flux). In addition, CGP significantly attenuated LPS-induced oxidative injury, and improved Cav-3 expression and eNOS activation, similar effects were shown by the treatment of autophagy inhibitor 3-MA. LPS-induced myocardial injury is associated with excessive PKCβ2 activation, which contributes to elevated autophagy and impaired Cav-3/eNOS signaling. Selective inhibition of PKCβ2 improves Cav-3/eNOS signaling and attenuates LPS-induced injury through inhibiting autophagy in H9C2 cardiomyocytes.

Interleukin-9 promotes intestinal barrier injury of sepsis: a translational research

Background

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Intestinal mucosal barrier injury is one of the important manifestations of sepsis. Interleukin-9 (IL-9) and IL-9-producing CD4(+) T cells were emerging pro-inflammatory mediators with development of intestinal injury. However, it is unclear whether IL-9 is related to the intestinal barrier injury of sepsis.

Methods

To investigate the roles of IL-9-producing CD4(+) T cells and IL-9 in the process of barrier injury in sepsis, serum IL-9-producing CD4(+) T cell percentages, IL-9, and D-lactate levels were measured in septic patients and controls. The markers of barrier function in serum and intestinal tissue were also collected in septic rats. Moreover, the barrier injury degree and survival rate of septic rats were also investigated after increasing or interfering with IL-9 expression.

Results

The serum IL-9-producing CD4(+) T cell percentages, IL-9, and D-lactate levels were significantly higher in septic patients or rats than those in controls. IL-9-producing CD4(+) T cells and IL-9 levels were positively correlated with D-lactate levels and had a high predictive value of 28-day mortality in septic patients. The non-survivors had significantly higher serum T cell percentages, IL-9, and D-lactate levels compared with survivors. In septic rats, IL-9 increased the expression levels of D-lactate, whereas that decreased the expression levels of zonula occludens 1. Moreover, the barrier injury was aggravated or alleviated by increasing or interfering with IL-9 expression, respectively. Survival rate analysis also showed that IL-9 decreased the 14-day survival rate of septic rats.

Conclusion

IL-9 is closely related to intestinal mucosal barrier injury and mortality in sepsis. IL-9 blockade has the potential to improve the barrier injury in sepsis.

Trial registration

The study was registered at ClinicalTrials.gov (ID: NCT03791866, Date: December 2018).

Pivotal role of endothelial cell autophagy in sepsis

Sepsis is a fatal organ dysfunction resulting from a disordered host response to infection. Endothelial cells (ECs) are usually the primary targets of inflammatory mediators in sepsis; damage to ECs plays a pivotal part in vital organ failure. In recent studies, autophagy was suggested to play a critical role in the ECs injury although the mechanisms by which ECs are injured in sepsis are not well elucidated. Autophagy is a highly conserved catabolic process that includes sequestrating plasma contents and transporting cargo to lysosomes for recycling the vital substrates required for metabolism. This pathway also counteracts microbial invasion to balance and retain homeostasis, especially during sepsis. Increasing evidence indicates that autophagy is closely associated with endothelial function. The role of autophagy in sepsis may or may not be favorable depending upon conditions. In the present review, the current knowledge of autophagy in the process of sepsis and its influence on ECs was evaluated. In addition, the potential of targeting EC autophagy for clinical treatment of sepsis was discussed.

[The critically ill CAR T-cell patient : Relevant toxicities, their management and challenges in critical care]

BACKGROUND

CAR‑T cell therapy has been implemented as clinical routine treatment option during the last decade. Despite beneficial outcomes in many patients severe side effects and toxicities are seen regularly that can compromise the treatment success.

METHODS

Literature review: CAR T‑cell therapy, toxicities and their management RESULTS: The cytokine release syndrome (CRS) and the immune effector cell-associated neurotoxicity syndrome (ICANS) are seen regularly after CAR T‑cell treatment. CRS symptoms can range from mild flu-like symptoms to severe organ dysfunction requiring vasopressor therapy, mechanical ventilation and other intensive care support. ICANS symptoms usually develop later and can range from disorientation and aphasia to potentially life-threatening brain edema. IL‑6 is a key factor in the pathophysiology of CRS. The pathophysiology of ICANS is not fully understood. The ASTCT consensus grading is recommended to stratify patients for different management options. An interdisciplinary team including hematologist, intensivist, neurologists and other specialties is needed to optimize the treatment.

DISCUSSION

Severe and potentially life-threatening toxicities occur regularly after CAR T‑cell therapy. Treatment strategies for CRS and ICANS still need to be evaluated prospectively. Due to the increasing number of patients treated with CAR T‑cells the number of patients requiring temporary intensive care management due to CRS and ICANS is expected to increase during the next years.

Clinical significance of sirtuin 1 level in sepsis: correlation with disease risk, severity, and mortality risk

This study aimed to investigate the value of sirtuin 1 (SIRT1) in differentiating sepsis patients from healthy controls (HCs), and its correlation with inflammation, disease severity, as well as prognosis in sepsis patients. Serum samples were collected from 180 sepsis patients and 180 age- and gender-matched HCs. The SIRT1 level in the serum samples was detected by enzyme-linked immunoassay. The clinical data of the sepsis patients were documented, and their disease severity scores and 28-day mortality rate were assessed. SIRT1 was decreased in sepsis patients compared with HCs, and the receiver operating characteristic curve (ROC) showed that SIRT1 distinguished sepsis patients from HCs (area under the curve (AUC): 0.901; 95% confidence interval (CI): 0.868-0.934). In sepsis patients, SIRT1 negatively correlated with serum creatinine (Scr), white blood cells (WBC), C-reactive protein (CRP), acute physiology, and chronic health evaluation II (APACHE II) score, and sequential organ failure assessment (SOFA) score, while it positively correlated with albumin. No correlation of SIRT1 with primary infection site or primary organism was observed. Furthermore, SIRT1 was reduced in 28-day non-survivors compared with 28-day survivors, and subsequent ROC showed that SIRT1 predicted 28-day mortality of sepsis patients (AUC: 0.725; 95% CI: 0.651-0.800), and its prognostic value was not inferior to Scr, albumin, WBC, and CRP, but was less than SOFA score and APACHE II score. In conclusion, measurement of serum SIRT1 might assist with the optimization of disease assessment, management strategies, and survival surveillance in sepsis patients.

GFI-1 Protects Against Lipopolysaccharide-Induced Inflammatory Responses and Apoptosis by Inhibition of the NF-κB/TNF-α Pathway in H9c2 Cells

Growth factor independence 1 (Gfi-1) has been widely studied for its anti-inflammatory and anti-apoptotic effects. However, whether Gfi-1 has similar effects on H9c2 cardiomyocytes has not yet been reported. In this study, we explored the effect of Gfi-1 on lipopolysaccharide (LPS)-induced inflammatory responses and apoptosis in H9c2 cells. We found that LPS induced the increased expression of TNF-α and IL-6 in the LPS group. After transfection of the Gfi-1 overexpression plasmid, the expression of TNF-α and IL-6 decreased significantly in the LPS + Gfi-1 group. Gfi-1 clearly blocked LPS-induced NF-κB, TNF-α, TNFR1, cleaved-caspase-3 and cleaved-caspase-8 expression and increased Gfi-1 and Bcl-xL expression in H9c2 cells. Similarly, compared with the LPS group, Gfi-1 significantly decreased the expression of cleaved-caspase3/8 and increased the expression of Bcl-xL in the LPS + Gfi-1 group, as verified by immunocytochemical analysis. Furthermore, Gfi-1 markedly inhibited LPS-induced H9c2 cardiomyocyte apoptosis in the LPS + Gfi-1 group, as determined by TEM, TUNEL and flow cytometry. Taken together, these results demonstrate that Gfi-1 may have protective effects against LPS-induced inflammatory responses and apoptosis in H9c2 cells. Gfi-1 may be a novel molecule for treating septic cardiomyopathy.

Identification of key genes and novel immune infiltration-associated biomarkers of sepsis

Sepsis is the major cause of mortality in the intensive care unit. The aim of this study was to identify the key prognostic biomarkers of abnormal expression and immune infiltration in sepsis. In this study, a total of 36 differentially expressed genes were identified to be mainly involved in a number of immune-related Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways. The hub genes (MMP9 and C3AR1) were significantly related to the prognosis of sepsis patients. The immune infiltration analysis indicated a significant difference in the relative cell content of naive B cells, follicular Th cells, activated NK cells, eosinophils, neutrophils and monocytes between sepsis and normal controls. Weighted gene co-expression network analysis and a de-convolution algorithm that quantifies the cellular composition of immune cells were used to analyse the sepsis expression data from the Gene Expression Omnibus database and to identify modules related to differential immune cells. CEBPB is the key immune-related gene that may be involved in sepsis. Gene set enrichment analysis revealed that CEBPB is involved in the processes of T cell selection, B cell–mediated immunity, NK cell activation and pathways of T cells, B cells and NK cells. Therefore, CEBPB may play a key role in the biological and immunological processes of sepsis.

The value of biomarker-guided antibiotic therapy

INTRODUCTION

There is an increasing interest to individualize patient management and decisions regarding antibiotic treatment. Biomarkers may provide relevant information for this purpose.

AREAS COVERED

Despite a growing number of clinical trials investigating several biomarkers, there remain open questions regarding the best type of biomarker, timing or frequency of testing, and optimal cutoffs among others. The most promising results in regard to diagnosis of bacterial infection and therapy monitoring are found for procalcitonin (PCT), although some recent trials were not able to validate the promising earlier findings. Furthermore, less specific markers like C-reactive protein (CRP) and new prognostic biomarkers such as proadrenomedullin (MR-proADM) may improve the prognostic assessment of patients and proteomics may help shorten time to microbiological results. The aim of this review is to summarize the current concept of biomarker-guided management and provide an outlook of promising ongoing investigations.

EXPERT OPINION

'Antibiotic stewardship' is complex and needs more than just the measurement of one single biomarker. However, when integrated into the context of a thorough clinical examination, standard blood parameters and a well done risk stratification by clinical scores such as the SOFA-score, biomarkers have great potential to improve the diagnostic and prognostic assessment of patients.

SEPSIS. Educational and Best Practice Frontiers. Beyond the Boundaries of Fatality, Enhancing Clinical Skills and Precision Medicine

Dissemination and exploitation of knowledge regarding affordable clinical skills and innovative precision medicine, two current topics in active development in medicine, may contribute to improve also sepsis management. Sepsis is a life-threatening organ dysfunction due to a dysregulated host response to infection. Sepsis is strongly related to all body organs or to systemic diseases and to the quality of the best-practice in use, which is particularly critical in surgical or intervention techniques. Trauma, surgical and mini-invasive procedures, vascular or endoscopic interventions, otolaryngology, obstetrics-gynecological and urological procedures, malnutrition, dental, skin, chronic liver, kidney and respiratory disease are frequently involved. Accordingly, apart from the clinical risk analysis and management of the process of care, the actual factors that may be easily neglected are the techniques used, the personal skills of the health professionals and the quality of the equipment. The quest for biomarkers consistent with the unmet needs of medical doctors and of their patient and the efforts for overcoming bacterial antibiotic resistances are currently the main foci of medical research. In addition, in this regard, research and innovation would benefit from greater knowledge, skills and use of bioinformatics and omics. The caveats related to in-silico approaches must be flagged: algorithms may equally warrant scientific innovations or hide the lack of them; a patient is more than a set of covariates. Epidemiology and prevention includes all the actions suitable for achieving an adequate hygiene and immunization of populations and for safer hospital policies and procedures during Patients’ stays. In any subset, the most unresolved critical point in sepsis is a timely diagnosis. This is impaired by low degrees of suspicion for the possibility of emerging sepsis, by the shortage of use of the simplest microbiological testing but, equally or more, by the insufficient diffusion of non-invasive imaging skills suitable to detect and monitor the emerging sites and sources of infection. In primary care, in emergency facilities, in hospital wards and in intensive care units, inclusion of appropriate knowledge, skills, expertise and imaging equipment must be extended as much as possible. The low cost of UltraSound machines and of increasing bioinformatics literacy by e-learning, makes such investments affordable even in limited-resources contexts. Frontier educational and best practice intervention enhancing affordable clinical skills and innovative precision medicine may lead beyond the boundaries of fatal outcomes in sepsis.

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Thioredoxin-2 impacts the inflammatory response via suppression of NF-κB and MAPK signaling in sepsis shock

Sepsis is a progressive disease characterized by excessive inflammatory responses, severe tissue injury and organ dysfunction, ultimately leading to mortality. In this study, we demonstrated that thioredoxin-2 (TRX-2) expression is reduced in macrophages stimulated with lipopolysaccharide (LPS). Overexpression of TRX-2 significantly attenuated interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) production induced by LPS. TRX-2 inhibited LPS-induced inflammatory responses through suppressing activation of the NF-κB and MAPK signaling pathways. Furthermore, TRX-2 induced a significant decrease in mortality in mouse sepsis models in association with reduced inflammatory cytokine production and attenuation of organ injury. Our data collectively support a role of TRX-2 as a critical regulator of sepsis that influences survival by protecting the host from excessive inflammatory damage.

Surviving Sepsis Campaign: Research Priorities for Sepsis and Septic Shock

OBJECTIVE

To identify research priorities in the management, epidemiology, outcome and underlying causes of sepsis and septic shock.

DESIGN

A consensus committee of 16 international experts representing the European Society of Intensive Care Medicine and Society of Critical Care Medicine was convened at the annual meetings of both societies. Subgroups had teleconference and electronic-based discussion. The entire committee iteratively developed the entire document and recommendations.

METHODS

Each committee member independently gave their top five priorities for sepsis research. A total of 88 suggestions (Supplemental Table 1, Supplemental Digital Content 2, http://links.lww.com/CCM/D636) were grouped into categories by the committee co-chairs, leading to the formation of seven subgroups: infection, fluids and vasoactive agents, adjunctive therapy, administration/epidemiology, scoring/identification, post-intensive care unit, and basic/translational science. Each subgroup had teleconferences to go over each priority followed by formal voting within each subgroup. The entire committee also voted on top priorities across all subgroups except for basic/translational science.

RESULTS

The Surviving Sepsis Research Committee provides 26 priorities for sepsis and septic shock. Of these, the top six clinical priorities were identified and include the following questions: 1) can targeted/personalized/precision medicine approaches determine which therapies will work for which patients at which times?; 2) what are ideal endpoints for volume resuscitation and how should volume resuscitation be titrated?; 3) should rapid diagnostic tests be implemented in clinical practice?; 4) should empiric antibiotic combination therapy be used in sepsis or septic shock?; 5) what are the predictors of sepsis long-term morbidity and mortality?; and 6) what information identifies organ dysfunction?

CONCLUSIONS

While the Surviving Sepsis Campaign guidelines give multiple recommendations on the treatment of sepsis, significant knowledge gaps remain, both in bedside issues directly applicable to clinicians, as well as understanding the fundamental mechanisms underlying the development and progression of sepsis. The priorities identified represent a roadmap for research in sepsis and septic shock.

Sepsis-Associated Coagulopathy Severity Predicts Hospital Mortality

OBJECTIVES

To assess whether sepsis-associated coagulopathy predicts hospital mortality.

DESIGN

Retrospective cohort study.

SETTING

One-thousand three-hundred beds urban academic medical center.

PATIENTS

Six-thousand one-hundred forty-eight consecutive patients hospitalized between January 1, 2010, and December 31, 2015.

INTERVENTIONS

Mild sepsis-associated coagulopathy was defined as an international normalized ratio greater than or equal to 1.2 and less than 1.4 plus platelet count less than or equal to 150,000/µL but greater than 100,000/µL; moderate sepsis-associated coagulopathy was defined with either an international normalized ratio greater than or equal to 1.4 but less than 1.6 or platelets less than or equal to 100,000/µL but greater than 80,000/µL; severe sepsis-associated coagulopathy was defined as an international normalized ratio greater than or equal to 1.6 and platelets less than or equal to 80,000/µL.

MEASUREMENTS AND MAIN RESULTS

Hospital mortality increased progressively from 25.4% in patients without sepsis-associated coagulopathy to 56.1% in patients with severe sepsis-associated coagulopathy. Similarly, duration of hospitalization and ICU care increased progressively as sepsis-associated coagulopathy severity increased. Multivariable analyses showed that the presence of sepsis-associated coagulopathy, as well as sepsis-associated coagulopathy severity, was independently associated with hospital mortality regardless of adjustments made for baseline patient characteristics, hospitalization variables, and the sepsis-associated coagulopathy-cancer interaction. Odds ratios ranged from 1.33 to 2.14 for the presence of sepsis-associated coagulopathy and from 1.18 to 1.51 for sepsis-associated coagulopathy severity for predicting hospital mortality (p < 0.001 for all comparisons).

CONCLUSIONS

The presence of sepsis-associated coagulopathy identifies a group of patients with sepsis at higher risk for mortality. Furthermore, there is an incremental risk of mortality as the severity of sepsis-associated coagulopathy increases.

Timing of Renal Support and Outcome of Septic Shock and Acute Respiratory Distress Syndrome. A Post Hoc Analysis of the AKIKI Randomized Clinical Trial

RATIONALE

The optimal strategy for initiation of renal replacement therapy (RRT) in patients with severe acute kidney injury in the context of septic shock and acute respiratory distress syndrome (ARDS) is unknown.

OBJECTIVES

To examine the effect of an early compared with a delayed RRT initiation strategy on 60-day mortality according to baseline sepsis status, ARDS status, and severity.

METHODS

Post hoc analysis of the AKIKI (Artificial Kidney Initiation in Kidney Injury) trial.

MEASUREMENTS AND MAIN RESULTS

Subgroups were defined according to baseline characteristics: sepsis status (Sepsis-3 definition), ARDS status (Berlin definition), Simplified Acute Physiology Score 3 (SAPS 3), and Sepsis-related Organ Failure Assessment (SOFA). Of 619 patients, 348 (56%) had septic shock and 207 (33%) had ARDS. We found no significant influence of the baseline sepsis status (P = 0.28), baseline ARDS status (P = 0.94), and baseline severity scores (P = 0.77 and P = 0.46 for SAPS 3 and SOFA, respectively) on the comparison of 60-day mortality according to RRT initiation strategy. A delayed RRT initiation strategy allowed 45% of patients with septic shock and 46% of patients with ARDS to escape RRT. Urine output was higher in the delayed group. Renal function recovery occurred earlier with the delayed RRT strategy in patients with septic shock or ARDS (P < 0.001 and P = 0.003, respectively). Time to successful extubation in patients with ARDS was not affected by RRT strategy (P = 0.43).

CONCLUSIONS

Early RRT initiation strategy was not associated with any improvement of 60-day mortality in patients with severe acute kidney injury and septic shock or ARDS. Unnecessary and potentially risky procedures might often be avoided in these fragile populations. Clinical trial registered with www.clinicaltrials.gov (NCT 01932190).

Sepsis information-seeking behaviors via Wikipedia between 2015 and 2018: A mixed methods retrospective observational study

Raising public awareness of sepsis, a potentially life-threatening dysregulated host response to infection, to hasten its recognition has become a major focus of physicians, investigators, and both non-governmental and governmental agencies. While the internet is a common means by which to seek out healthcare information, little is understood about patterns and drivers of these behaviors. We sought to examine traffic to Wikipedia, a popular and publicly available online encyclopedia, to better understand how, when, and why users access information about sepsis. Utilizing pageview traffic data for all available language localizations of the sepsis and septic shock pages between July 1, 2015 and June 30, 2018, significantly outlying daily pageview totals were identified using a seasonal hybrid extreme studentized deviate approach. Consecutive outlying days were aggregated, and a qualitative analysis was undertaken of print and online news media coverage to identify potential correlates. Traffic patterns were further characterized using paired referrer to resource (i.e. clickstream) data, which were available for a temporal subset of the pageviews. Of the 20,557,055 pageviews across 65 linguistic localizations, 47 of the 1,096 total daily pageview counts were identified as upward outliers. After aggregating sequential outlying days, 25 epochs were examined. Qualitative analysis identified at least one major news media correlate for each, which were typically related to high-profile deaths from sepsis and, less commonly, awareness promotion efforts. Clickstream analysis suggests that most sepsis and septic shock Wikipedia pageviews originate from external referrals, namely search engines. Owing to its granular and publicly available traffic data, Wikipedia holds promise as a means by which to better understand global drivers of online sepsis information seeking. Further characterization of user engagement with this information may help to elucidate means by which to optimize the visibility, content, and delivery of awareness promotion efforts.

Relationship between Nutrition Intake and 28-Day Mortality Using Modified NUTRIC Score in Patients with Sepsis

In critically ill patients, malnutrition is known to increase morbidity and mortality. We investigated the relationship between nutritional support and 28-day mortality using the modified NUTrition RIsk in the Critically ill (NUTRIC) score in patients with sepsis. This retrospective cohort study included patients with sepsis admitted to the medical intensive care unit (ICU) between January 2011 and June 2017. Nutritional support for energy and protein intakes at day 7 of ICU admission were categorized into <20, 20 to <25, and ≥25 kcal/kg and <1.0, 1.0 to <1.2, and ≥1.2 g/kg, respectively. NUTRIC scores ≥4 were considered to indicate high nutritional risk. Among patients with low nutritional risk, higher intakes of energy (≥25 kcal/kg) and protein (≥1.2 g/kg) were not significantly associated with lower 28-day mortality. In patients with high nutritional risk, higher energy intakes of ≥25 kcal/kg were significantly associated with lower 28-day mortality compared to intakes of <20 kcal/kg (adjusted hazard ratio (aHR): 0.569, 95% confidence interval (CI): 0.339-0.962, p = 0.035). Higher protein intakes of ≥1.2 g/kg were also significantly associated with lower 28-day mortality compared to intakes of <1.0 g/kg (aHR: 0.502, 95% CI: 0.280-0.900, p = 0.021). Appropriate energy (≥25 kcal/kg) and protein (≥1.2 g/kg) intakes during the first week may improve outcomes in patients with sepsis having high nutritional risk.

MiR-21-3p Plays a Crucial Role in Metabolism Alteration of Renal Tubular Epithelial Cells during Sepsis Associated Acute Kidney Injury via AKT/CDK2-FOXO1 Pathway

Objective

Sepsis and associated acute kidney injury (SAKI) are determined to be closely related to poor prognosis. Because the metabolic alterations of tubular epithelial cells (TECs) are crucial for the occurrence and development of SAKI, we carried out this present study to identify the metabolism changes of TECs during SAKI and relevant mechanisms.

Methods

Rat SAKI model and rat tubular epithelial cell line were used in our study. ELISA was used to determine the serum cytokines levels. Protein expressions were examined with Western-Blotting and the transcriptions of RNAs were determined with qRT-PCR. ADP/ATP assay and Oil Red O staining were used to examine the energy and lipid metabolism, respectively. Dual-luciferase reporter assay was carried out to determine the interactions between miRNA and specific proteins. Cell cycle arrest and apoptosis were determined with flow cytometry.

Results

Sepsis and AKI were induced 12 h after CLP. Energy and lipid metabolism reduced significantly while FOXO1 levels increased remarkably in TECs during SAKI. The expressions of both AKT and CDK2 and the transcriptions of relevant mRNAs reduced significantly in TECs during SAKI while miR-21-3p expression increased remarkably. Both AKT and CDK2 were determined as the direct targets of miR-21-3p. Furthermore, by in vitro experiments, it was demonstrated that FOXO1 levels were regulated by miR-21-3p in TECs via AKT/CDK2 and AKT/CDK2-FOXO1 pathway was crucial in the regulations of miR-21-3p on lipid metabolism, cell cycle arrest, and apoptosis of TECs.

Conclusions

MiR-21-3p mediates metabolism and cell fate alterations of TECs via manipulating AKT/CDK2-FOXO1 pathway, and that is crucial in the regulation of energy metabolism of TECs during SAKI.

Increased gene copy number of DEFA1/DEFA3 worsens sepsis by inducing endothelial pyroptosis

Sepsis claims an estimated 30 million episodes and 6 million deaths per year, and treatment options are rather limited. Human neutrophil peptides 1-3 (HNP1-3) are the most abundant neutrophil granule proteins but their neutrophil content varies because of unusually extensive gene copy number polymorphism. A genetic association study found that increased copy number of the HNP-encoding gene DEFA1/DEFA3 is a risk factor for organ dysfunction during sepsis development. However, direct experimental evidence demonstrating that these risk alleles are pathogenic for sepsis is lacking because the genes are present only in some primates and humans. Here, we generate DEFA1/DEFA3 transgenic mice with neutrophil-specific expression of the peptides. We show that mice with high copy number of DEFA1/DEFA3 genes have more severe sepsis-related vital organ damage and mortality than mice with low copy number of DEFA1/DEFA3 or wild-type mice, resulting from more severe endothelial barrier dysfunction and endothelial cell pyroptosis after sepsis challenge. Mechanistically, HNP-1 induces endothelial cell pyroptosis via P2X7 receptor-mediating canonical caspase-1 activation in a NLRP3 inflammasome-dependent manner. Based on these findings, we engineered a monoclonal antibody against HNP-1 to block the interaction with P2X7 and found that the blocking antibody protected mice carrying high copy number of DEFA1/DEFA3 from lethal sepsis. We thus demonstrate that DEFA1/DEFA3 copy number variation strongly modulates sepsis development in vivo and explore a paradigm for the precision treatment of sepsis tailored by individual genetic information.

Early PREdiction of sepsis using leukocyte surface biomarkers: the ExPRES-sepsis cohort study

PURPOSE

Reliable biomarkers for predicting subsequent sepsis among patients with suspected acute infection are lacking. In patients presenting to emergency departments (EDs) with suspected acute infection, we aimed to evaluate the reliability and discriminant ability of 47 leukocyte biomarkers as predictors of sepsis (Sequential Organ Failure Assessment score ≥ 2 at 24 h and/or 72 h following ED presentation).

METHODS

In a multi-centre cohort study in four EDs and intensive care units (ICUs), we standardised flow-cytometric leukocyte biomarker measurement and compared patients with suspected acute infection (cohort-1) with two comparator cohorts: ICU patients with established sepsis (cohort-2), and ED patients without infection or systemic inflammation but requiring hospitalization (cohort-3).

RESULTS

Between January 2014 and February 2016, we recruited 272, 59 and 75 patients to cohorts 1, 2, and 3, respectively. Of 47 leukocyte biomarkers, 14 were non-reliable, and 17 did not discriminate between the three cohorts. Discriminant analyses for predicting sepsis within cohort-1 were undertaken for eight neutrophil (cluster of differentiation antigens (CD) CD15; CD24; CD35; CD64; CD312; CD11b; CD274; CD279), seven monocyte (CD35; CD64; CD312; CD11b; HLA-DR; CD274; CD279) and a CD8 T-lymphocyte biomarker (CD279). Individually, only higher neutrophil CD279 [OR 1.78 (95% CI 1.23-2.57); P = 0.002], higher monocyte CD279 [1.32 (1.03-1.70); P = 0.03], and lower monocyte HLA-DR [0.73 (0.55-0.97); P = 0.03] expression were associated with subsequent sepsis. With logistic regression the optimum biomarker combination was increased neutrophil CD24 and neutrophil CD279, and reduced monocyte HLA-DR expression, but no combination had clinically relevant predictive validity.

CONCLUSIONS

From a large panel of leukocyte biomarkers, immunosuppression biomarkers were associated with subsequent sepsis in ED patients with suspected acute infection.

CLINICAL TRIAL REGISTRATION

NCT02188992.

Surviving sepsis campaign: research priorities for sepsis and septic shock

Objective

To identify research priorities in the management, epidemiology, outcome and underlying causes of sepsis and septic shock.

Design

A consensus committee of 16 international experts representing the European Society of Intensive Care Medicine and Society of Critical Care Medicine was convened at the annual meetings of both societies. Subgroups had teleconference and electronic-based discussion. The entire committee iteratively developed the entire document and recommendations.

Methods

Each committee member independently gave their top five priorities for sepsis research. A total of 88 suggestions (ESM 1 - supplemental table 1) were grouped into categories by the committee co-chairs, leading to the formation of seven subgroups: infection, fluids and vasoactive agents, adjunctive therapy, administration/epidemiology, scoring/identification, post-intensive care unit, and basic/translational science. Each subgroup had teleconferences to go over each priority followed by formal voting within each subgroup. The entire committee also voted on top priorities across all subgroups except for basic/translational science.

Results

The Surviving Sepsis Research Committee provides 26 priorities for sepsis and septic shock. Of these, the top six clinical priorities were identified and include the following questions: (1) can targeted/personalized/precision medicine approaches determine which therapies will work for which patients at which times?; (2) what are ideal endpoints for volume resuscitation and how should volume resuscitation be titrated?; (3) should rapid diagnostic tests be implemented in clinical practice?; (4) should empiric antibiotic combination therapy be used in sepsis or septic shock?; (5) what are the predictors of sepsis long-term morbidity and mortality?; and (6) what information identifies organ dysfunction?

Conclusions

While the Surviving Sepsis Campaign guidelines give multiple recommendations on the treatment of sepsis, significant knowledge gaps remain, both in bedside issues directly applicable to clinicians, as well as understanding the fundamental mechanisms underlying the development and progression of sepsis. The priorities identified represent a roadmap for research in sepsis and septic shock.

Electronic supplementary material

The online version of this article (10.1007/s00134-018-5175-z) contains supplementary material, which is available to authorized users.

Mesenchymal stromal cell-derived extracellular vesicles: regenerative and immunomodulatory effects and potential applications in sepsis

Mesenchymal stromal (stem) cells (MSCs) have multipotent differentiation capacity and exist in nearly all forms of post-natal organs and tissues. The immunosuppressive and anti-inflammatory properties of MSCs have made them an ideal candidate in the treatment of diseases, such as sepsis, in which inflammation plays a critical role. One of the key mechanisms of MSCs appears to derive from their paracrine activity. Recent studies have demonstrated that MSC-derived extracellular vesicles (MSC-EVs) are at least partially responsible for the paracrine effect. MSC-EVs transfer molecules (such as proteins/peptides, mRNA, microRNA and lipids) with immunoregulatory properties to recipient cells. MSC-EVs have been shown to mimic MSCs in alleviating sepsis and may serve as an alternative to whole cell therapy. Compared with MSCs, MSC-EVs may offer specific advantages due to lower immunogenicity and higher safety profile. The first two sections of the review discuss the preclinical and clinical findings of MSCs in sepsis. Next, we review the characteristics of EVs and MSC-EVs. Then, we summarize the mechanisms of MSC-EVs, including tissue regeneration and immunomodulation. Finally, our review presents the evidences that MSC-EVs are effective in treating models of sepsis. In conclusion, MSC-EVs may have the potential to become a novel therapeutic strategy for sepsis.

Subnanometer Gold Clusters Adhere to Lipid A for Protection against Endotoxin-Induced Sepsis

Endotoxicity originating from a dangerous debris (i.e., lipopolysaccharide, LPS) of Gram-negative bacteria is a challenging clinical problem, but no drugs or therapeutic strategies that can successfully address this issue have been identified yet. In this study, we report a subnanometer gold cluster that can efficiently block endotoxin activity to protect against sepsis. The endotoxin blocker consists of a gold nanocluster that serves as a flakelike substrate and a coating of short alkyl motifs that act as an adhesive to dock with LPS by compacting the intramolecular hydrocarbon chain-chain distance ( d-spacing) of lipid A, an endotoxicity active site that can cause overwhelming cytokine induction resulting in sepsis progression. Direct evidence showed the d-spacing values of lipid A to be decreased from 4.19 Å to either 3.85 or 3.54 Å, indicating more dense packing densities in the presence of subnanometer gold clusters. In terms of biological relevance, the concentrations of key pro-inflammatory NF-κB-dependent cytokines, including plasma TNF-α, IL-6, and IL-1β, and CXC chemokines, in LPS-challenged mice showed a noticeable decrease. More importantly, we demonstrated that the treatment of antiendotoxin gold nanoclusters significantly prolonged the survival time in LPS-induced septic mice. The ultrasmall gold nanoclusters could target lipid A of LPS to deactivate endotoxicity by compacting its packing density, which might constitute a potential therapeutic strategy for the early prevention of sepsis caused by Gram-negative bacterial infection.

Expert statement for the management of hypovolemia in sepsis

Hypovolemia is frequent in patients with sepsis and may contribute to worse outcome. The management of these patients is impeded by the low quality of the evidence for many of the specific components of the care. In this paper, we discuss recent advances and controversies in this field and give expert statements for the management of hypovolemia in patients with sepsis including triggers and targets for fluid therapy and volumes and types of fluid to be given. Finally, we point to unanswered questions and suggest a roadmap for future research.

Systemic bioinformatics analysis of skeletal muscle gene expression profiles of sepsis

Sepsis is a type of systemic inflammatory response syndrome with high morbidity and mortality. Skeletal muscle dysfunction is one of the major complications of sepsis that may also influence the outcome of sepsis. The aim of the present study was to explore and identify potential mechanisms and therapeutic targets of sepsis. Systemic bioinformatics analysis of skeletal muscle gene expression profiles from the Gene Expression Omnibus was performed. Differentially expressed genes (DEGs) in samples from patients with sepsis and control samples were screened out using the limma package. Differential co-expression and coregulation (DCE and DCR, respectively) analysis was performed based on the Differential Co-expression Analysis package to identify differences in gene co-expression and coregulation patterns between the control and sepsis groups. Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways of DEGs were identified using the Database for Annotation, Visualization and Integrated Discovery, and inflammatory, cancer and skeletal muscle development-associated biological processes and pathways were identified. DCE and DCR analysis revealed several potential therapeutic targets for sepsis, including genes and transcription factors. The results of the present study may provide a basis for the development of novel therapeutic targets and treatment methods for sepsis.

The effects of tumor necrosis factor-α (TNF-α) rs1800629 and rs361525 polymorphisms on sepsis risk

This meta-analysis of 23 eligible articles comprehensively and quantitatively evaluated the effects of tumor necrosis factor-α (TNF-α) rs1800629 and rs361525 polymorphisms on sepsis risk. We found that TNF-α rs1800629 was associated with increased sepsis risk in the overall population in four genetic models, including A vs. G (P<0.001, odds ratio (OR)=1.32), GA vs. GG (P<0.001, OR=1.46), GA+AA vs. GG (P<0.001, OR=1.46), and carrier A vs. carrier G (P<0.001, OR=1.32). Subgroup analyses showed a similar result for Asian patients (all P<0.05, OR>1). TNF-α rs361525 was also associated with increased sepsis risk in Asian patients in the four genetic models (all P<0.05, OR>1). Begg's and Egger's tests excluded large publication bias, and sensitivity analysis indicated stable results. Our results suggest that the G/A genotype of TNF-α rs1800629 and rs361525 increases sepsis risk in an Asian population.

Sphingosine 1-Phosphate- and C-C Chemokine Receptor 2-Dependent Activation of CD4+ Plasmacytoid Dendritic Cells in the Bone Marrow Contributes to Signs of Sepsis-Induced Immunosuppression

Sepsis is the dysregulated response of the host to systemic, mostly bacterial infection, and is associated with an enhanced susceptibility to life-threatening opportunistic infections. During polymicrobial sepsis, dendritic cells (DCs) secrete enhanced levels of interleukin (IL) 10 due to an altered differentiation in the bone marrow and contribute to the development of immunosuppression. We investigated the origin of the altered DC differentiation using murine cecal ligation and puncture (CLP), a model for human polymicrobial sepsis. Bone marrow cells (BMC) were isolated after sham or CLP operation, the cellular composition was analyzed, and bone marrow-derived DCs (BMDCs) were generated in vitro. From 24 h on after CLP, BMC gave rise to BMDC that released enhanced levels of IL-10. In parallel, a population of CD11c^hiMHCII⁺CD4⁺ DCs expanded in the bone marrow in a MyD88-dependent manner. Prior depletion of the CD11c^hiMHCII⁺CD4⁺ DCs from BMC in vitro reversed the increased IL-10 secretion of subsequently differentiating BMDC. The expansion of the CD11c^hiMHCII⁺CD4⁺ DC population in the bone marrow after CLP required the function of sphingosine 1-phosphate receptors and C-C chemokine receptor (CCR) 2, the receptor for C-C chemokine ligand (CCL) 2, but was not associated with monocyte mobilization. CD11c^hiMHCII⁺CD4⁺ DCs were identified as plasmacytoid DCs (pDCs) that had acquired an activated phenotype according to their increased expression of MHC class II and CD86. A redistribution of CD4⁺ pDCs from MHC class II⁻ to MHC class II⁺ cells concomitant with enhanced expression of CD11c finally led to the rise in the number of CD11c^hiMHCII⁺CD4⁺ DCs. Enhanced levels of CCL2 were found in the bone marrow of septic mice and the inhibition of CCR2 dampened the expression of CD86 on CD4⁺ pDCs after CLP in vitro. Depletion of pDCs reversed the bias of splenic DCs toward increased IL-10 synthesis after CLP in vivo. Thus, during polymicrobial sepsis, CD4⁺ pDCs are activated in the bone marrow and induce functional reprogramming of differentiating BMDC toward an immunosuppressive phenotype.

Biomarkers in Sepsis

A biomarker is a characteristic by which a (patho)physiologic process can be identified. Biomarkers can be of diagnostic value (to discriminate infection from noninfectious conditions or to determine the causative pathogen), of prognostic value (assigning risk profiles and predict outcome), and in the future may be of theranostic value (aid in selection and monitoring of therapy). Systems biology provides a promising tool for the discovery of novel biomarkers. Biomarkers can be the key to personalized targeted treatment in the future clinical management of sepsis.