Sepsis - What's new in 2019?

Novel therapeutic role of Ganoderma Polysaccharides in a septic mouse model - The key role of macrophages

Ganoderma lucidum polysaccharides (G. PS) have been recognized for their immune-modulating properties. In this study, we investigated the impact of G. PS in a sepsis mouse model, exploring its effects on survival, inflammatory cytokines, Treg cell differentiation, bacterial load, organ dysfunction, and related pathways. We also probed the role of macrophages through chlorphosphon-liposome pretreatment. Using the cecal ligation and puncture (CLP) model, we categorized mice into normal, PBS, and G. PS injection groups. G. PS significantly enhanced septic mouse survival, regulated inflammatory cytokines (TNF-α, IL-17A, IL-6, IL-10), and promoted CD4+Foxp3+ Treg cell differentiation in spleens. Additionally, G. PS reduced bacterial load, mitigated organ damage, and suppressed the NF-κB pathway. In vitro, G. PS facilitated CD4+ T cell differentiation into Treg cells via the p-STAT5 pathway. Chlorphosphon-liposome pretreatment heightened septic mortality, bacterial load, biochemical markers, and organ damage, emphasizing macrophages' involvement. G. PS demonstrated significant protective effects in septic mice by modulating inflammatory responses, enhancing Treg cell differentiation, diminishing bacterial load, and inhibiting inflammatory pathways. These findings illuminate the therapeutic potential of G. PS in sepsis treatment.

Factors influencing procalcitonin in the cerebrospinal fluid of patients after neurosurgery and its diagnostic value for intracranial infection

OBJECTIVE

This study aimed to investigate the factors influencing Procalcitonin (PCT) in the cerebrospinal fluid (CSF) of patients with high fever and suspected intracranial infection after neurosurgery and its clinical application value.

METHODS

Between February 2021 and August 2022, CSF and serum samples were collected via lumbar puncture from patients with high fever and suspected intracranial infection in the Intensive Care Unit(ICU) of our hospital. Multivariate logistic regression analysis was performed to analyze the factors influencing elevated PCT in CSF. The diagnostic efficacy of each index was assessed using receiver operating characteristic (ROC) curves.

RESULTS

A total of 183 CSF samples were collected, of which 148 had increased PCT levels, including 73 cases of intracranial infection and 75 cases in the case‒control group. Multivariate logistic regression analysis showed that intracranial infection [OR = 0.117, 95% CI: 0.025-0.559; p < 0.01] and hemorrhagic CSF [OR = 0.162, 95% CI: 0.029-0.916; p < 0.04] were factors influencing CSF PCT, while trauma [OR = 3.43, 95% CI: 0.76-15.45; p < 0.12], epileptic seizure [OR = 0.00, 95% CI: 0.00; p < 0], age [OR = 1.02, 95% CI: 0.98-1.52; p < 0.32] and Glasgow Coma Scale (GCS) score [OR = 1.03, 95% CI: 0.78-1.32; p < 0.83] did not influence CSF PCT. The CSF PCT and serum PCT levels in the intracranial infection group and the case‒control group were 0.13 (0.11, 0.25) ng/ml and 0.14 (0.07, 0.25) ng/ml and 0.14 (0.08,0.32) ng/ml and 0.23 (0.13,0.48)ng/ml, respectively, with no statistically significant difference. The median values of CSF lactate in the intracranial infection group and the case‒control group were 6.45 (4.475, 8.325) mmol/l and 3.2 (2.02, 4.200) mmol/l, respectively, with a statistically significant difference between the groups.The areas under the ROC curve of CSF PCT, serum PCT,CSF lactate, CSF PCT combined with lactate were 0.59, 0.63, 0.82,and 0.83,respectively.

CONCLUSION

Intracranial infection and hemorrhagic CSF are influencing factors for elevated CSF PCT following neurosurgery. It should be noted that the diagnostic value of intracranial infection by CSF PCT elevated alone is limited, but the combination it with other indicators can help improve diagnostic efficacy.

Postoperative systemic inflammatory dysregulation and corticosteroids: a narrative review

In some patients, the inflammatory-immune response to surgical injury progresses to a harmful, dysregulated state. We posit that postoperative systemic inflammatory dysregulation forms part of a pathophysiological response to surgical injury that places patients at increased risk of complications and subsequently prolongs hospital stay. In this narrative review, we have outlined the evolution, measurement and prediction of postoperative systemic inflammatory dysregulation, distinguishing it from a healthy and self-limiting host response. We reviewed the actions of glucocorticoids and the potential for heterogeneous responses to peri-operative corticosteroid supplementation. We have then appraised the evidence highlighting the safety of corticosteroid supplementation, and the potential benefits of high/repeated doses to reduce the risks of major complications and death. Finally, we addressed how clinical trials in the future should target patients at higher risk of peri-operative inflammatory complications, whereby corticosteroid regimes should be tailored to modify not only the a priori risk, but also further adjusted in response to markers of an evolving pathophysiological response.

Predictive value of procalcitonin level for pharyngocutaneous fistula after laryngectomy

BACKGROUND

Pharyngocutaneous fistula (PCF) is among the most common postoperative infective complications following laryngectomy. Its diagnosis is often late and identified only after the formation of an abnormal, bacterial infection-harboring fistula track between the pharynx and the skin. This study was aimed at determining whether procalcitonin (PCT), white blood cell count (WBC), C-reactive protein (CRP), and neutrophil percentage are good predictors of PCF.

METHODS

We prospectively analysed 65 consecutive patients undergoing total laryngectomy. Clinicodemographic, surgical, and body mass index data were collected. Data on serum levels of PCT, WBC, CRP, and neutrophils were obtained before surgery and on postoperative days 2, 4, 6, 8, and 10 by immunofluorescence, immune turbidimetry, and automatic blood analyzer. The area under the receiving operating characteristic (ROC) curve was calculated for each marker.

RESULTS

There were 65 patients with a mean age of 60.34 years. The PCF occurrence rate was 18.46 % (12/65). Serum levels of PCT and CRP determined on postoperative day 2, 4, 6, 8, and 10 after surgery were higher in patients with PCF (P < 0.01). PCT level was identified as a good predictor area under the curve (AUC) > 0.800 on postoperative days 2, 4, and 6. Considering the sensitivity and specificity, the best combination was PCT on postoperative days 4, which with a cutoff level of 0.12 μg/L showed 91.67 % sensitivity and 100 % specificity.

CONCLUSIONS

Procalcitonin can predict PCF following laryngectomy. PCT > 0.12 μg/L on postoperative day 4 was a reliable predictor of PCF. This may help guide postoperative antibiotic management.

Progress in the Clinical Assessment and Treatment of Myocardial Depression in Critically Ill Patient with Sepsis

Myocardial inhibition is the main cause of death in patients with sepsis.In recent years, methodological differences in the diagnosis, assessment, and treatment of septic myocardial depression have been observed, and how to objectively and accurately evaluate the degree of myocardial depression and the timing of treatment strategies have generally been the focus of this area of research. Based on the relevant research at home and abroad, the current review summarizes the clinical characteristics, methodological diagnosis, and symptomatic treatment of septic myocardial depression. The aim of doing so is to provide a reference for the early identification and treatment of patients with sepsis and myocardial depression.

Methylomic and transcriptomic characterization of postoperative systemic inflammatory dysregulation

In this study, we define and validate a state of postoperative systemic inflammatory dysregulation (PSID) based on postoperative phenotypic extremes of plasma C-reactive protein concentration following major abdominal surgery. PSID manifested clinically with significantly higher rates of sepsis, complications, longer hospital stays and poorer short, and long-term outcomes. We hypothesized that PSID will be associated with, and potentially predicted by, altered patterns of genome-wide peripheral blood mononuclear cell differential DNA methylation and gene expression. We identified altered DNA methylation and differential gene expression in specific immune and metabolic pathways during PSID. Our findings suggest that dysregulation results in, or from, dramatic changes in differential DNA methylation and highlights potential targets for early detection and treatment. The combination of altered DNA methylation and gene expression suggests that dysregulation is mediated at multiple levels within specific gene sets and hence, nonspecific anti-inflammatory treatments such as corticosteroids alone are unlikely to represent an effective therapeutic strategy.

Procalcitonin for individualizing antibiotic treatment: an update with a focus on COVID-19

Procalcitonin (PCT) is useful for differentiating between viral and bacterial infections and for reducing the unnecessary use of antibiotics. As the rise of antimicrobial resistance reaches “alarming” levels according to the World Health Organization, the importance of using biomarkers, such as PCT to limit unnecessary antibiotic exposure has further increased. Randomized trials in patients with respiratory tract infections have shown that PCT has prognostic implications and its use, embedded in stewardship protocols, leads to reductions in the use of antibiotics in different clinical settings without compromising clinical outcomes. However, available data are heterogeneous and recent trials found no significant benefit. Still, from these trials, we have learned several key considerations for the optimal use of PCT, which depend on the clinical setting, severity of presentation, and pretest probability for bacterial infection. For patients with respiratory infections and sepsis, PCT can be used to determine whether to initiate antimicrobial therapy in low-risk settings and, together with clinical data, whether to discontinue antimicrobial therapy in certain high-risk settings. There is also increasing evidence regarding PCT-guided therapy in patients with coronavirus disease 2019 (COVID-19). This review provides an up-to-date overview of the use of PCT in different clinical settings and diseases, including a discussion about its potential to improve the care of patients with COVID-19.

Interleukin-27 as a Diagnostic Biomarker for Patients with Sepsis: A Meta-Analysis

Background

The present study was aimed to investigate the value of blood interleukin-27 (IL-27) as a diagnostic biomarker of sepsis.

Methods

We searched PubMed, EMBASE, the Cochrane Library, and the reference lists of relevant articles. All studies published up to October 21, 2020, which evaluated the accuracy of IL-27 levels for the diagnosis of sepsis were included. All the selected papers were assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). We used a bivariate random effects model to estimate sensitivity, specificity, diagnostic odds ratios (DOR), and a summary receiver operating characteristic curve (SROC). Deeks' funnel plot was used to illustrate the potential presence of publication bias.

Results

This meta-analysis included seven articles. The pooled sensitivity, specificity, and DOR were 0.85 (95% CI, 0.72-0.93), 0.72 (95% CI, 0.42-0.90), and 15 (95% CI, 3-72), respectively. The area under the summary receiver operating characteristic curve was 0.88 (95% CI, 0.84-0.90). The pooled I² statistic was 96.05 for the sensitivity and 96.65 for the specificity in the heterogeneity analysis. Deeks' funnel plot indicated no publication bias in this meta-analysis (P = 0.07).

Conclusions

The present results showed that IL-27 is a reliable diagnostic biomarker of sepsis, but it should be investigated in combination with other clinical tests and results.

Procalcitonin Exerts a Mediator Role in Septic Shock Through the Calcitonin Gene-Related Peptide Receptor

OBJECTIVES

Clinically, procalcitonin represents the most widely used biomarker of sepsis worldwide with unclear pathophysiologic significance to date. Pharmacologically, procalcitonin was shown to signal through both calcitonin receptor and calcitonin gene-related peptide receptor in vitro, yet the identity of its biologically relevant receptor remains unknown.

DESIGN

Prospective randomized animal investigations and in vitro human blood studies.

SETTING

Research laboratory of a university hospital.

SUBJECTS

C57BL/6J mice and patients with post-traumatic sepsis.

INTERVENTIONS

Procalcitonin-deficient mice were used to decipher a potential mediator role in experimental septic shock and identify the relevant receptor for procalcitonin. Cecal ligation and puncture and endotoxemia models were employed to investigate septic shock. Disease progression was evaluated through survival analysis, histology, proteome profiling, gene expression, and flow cytometry. Mechanistic studies were performed with cultured macrophages, dendritic cells, and gamma delta T cells. Main findings were confirmed in serum samples of patients with post-traumatic sepsis.

MEASUREMENTS AND MAIN RESULTS

Procalcitonin-deficient mice are protected from septic shock and show decreased pulmonary inflammation. Mechanistically, procalcitonin potentiates proinflammatory cytokine expression in innate immune cells, required for interleukin-17A expression in gamma delta T cells. In patients with post-traumatic sepsis, procalcitonin positively correlates with systemic interleukin-17A levels. In mice with endotoxemia, immunoneutralization of interleukin-17A inhibits the deleterious effect of procalcitonin on disease outcome. Although calcitonin receptor expression is irrelevant for disease progression, the nonpeptide calcitonin gene-related peptide receptor antagonist olcegepant, a prototype of currently introduced antimigraine drugs, inhibits procalcitonin signaling and increases survival time in septic shock.

CONCLUSIONS

Our experimental data suggest that procalcitonin exerts a moderate but harmful effect on disease progression in experimental septic shock. In addition, the study points towards the calcitonin gene-related peptide receptor as relevant for procalcitonin signaling and suggests a potential therapeutic application for calcitonin gene-related peptide receptor inhibitors in sepsis, which warrants further clinical investigation.

The effects of sepsis on endothelium and clinical implications

ABSTRACT

Sepsis accounts for nearly 700 000 deaths in Europe annually and is caused by an overwhelming host response to infection resulting in organ failure. The endothelium is an active contributor to sepsis and as such represents a major target for therapy. During sepsis, endothelial cells amplify the immune response and activate the coagulation system. They are both a target and source of inflammation and serve as a link between local and systemic immune responses. In response to cytokines produced by immune cells, the endothelium expresses adhesion molecules and produces vasoactive compounds, inflammatory cytokines, and chemoattractants, thus switching from an anticoagulant to procoagulant state. These responses contribute to local control of infection, but systemic activation can lead to microvascular thrombosis, capillary permeability, hypotension, tissue hypoxia, and ultimately tissue damage. This review focuses on the role of the endothelium in leucocyte adhesion and transmigration as well as production of reactive oxygen and nitrogen species, microRNAs and cytokines, formation of signalling microparticles, and disseminated intravascular coagulation. We also discuss alterations in endothelial permeability and apoptosis. Finally, we review the diagnostic potential of endothelial markers and endothelial pathways as therapeutic targets for this devastating disease.

An update on endotoxin neutralization strategies in Gram-negative bacterial infections

INTRODUCTION

Gram-negative bacterial infections represent still a severe problem of human health care, regarding the increase in multi-resistance against classical antibiotics and the lack of newly developed antimicrobials. For the fight against these germs, anti-infective agents must overcome and/or bind to the Gram-negative outer membrane consisting of a lipopolysaccharide (LPS, endotoxin) outer leaflet and an inner leaflet from phospholipids, with additional peripheral or integral membrane proteins (OMP's).

AREAS COVERED

The current article reviews data of existing therapeutic options and summarizes newer approaches for targeting and neutralizing endotoxins, ranging from in vitro over in vivo animal data to clinical applications by using databases such as Medline.

EXPERT OPINION

Conventional antibiotic treatment of the bacteria leads to their killing, but not necessary LPS neutralization, which may be a severe problem in particular for the systemic pathway. This is the reason why there is an increasing number of therapeutic approaches, which - besides combating whole bacteria - at the same time try to neutralize endotoxin within or outside the bacterial cells mainly responsible for the high inflammation induction in Gram-negative species.

Accuracy of circulating microRNAs in diagnosis of sepsis: a systematic review and meta-analysis

Objectives

The aim of this study was to systematically assess the accuracy of circulating microRNAs (miRNAs) as a promising biomarker for sepsis via a meta-analysis.

Methods

PubMed, Cochrane Library, Embase, Web of Science, Scopus, and Ovid databases were searched up to April 3, 2020. The Quality in Prognostic Studies (QUADAS-2) tool was used to assess methodological quality. The pooled sensitivity (Sen), specificity (Spe), positive or negative likelihood ratios (PLR or NLR), diagnostic odds ratio (DOR), curve, and area under the curve (AUC) were calculated with 95% confidence interval (95% CI). The overall accuracy (OA) of miRNAs, procalcitonin (PCT), and C-reactive protein (CRP) was analyzed by the chi-square test.

Results

A total of 22 records were eligible for systematic review, including 2210 sepsis, 426 systemic inflammatory response syndrome (SIRS), and 1076 healthy controls (HC). The pooled Sen, Spe, and DOR of miRNAs were 0.80 (95% CI 0.75–0.83), 0.85 (95% CI 0.80–0.89), and 22 (15–32), respectively. The DOR of PCT and CRP were 17 (95% CI 4–68) and 7 (95% CI 1–48), respectively. The OA value of miRNAs (79.02%) and PCT (76.95%) were higher than CRP (61.22%) (P < 0.000). The subgroup analysis indicated that miRNAs in adults, serum type, downregulation of miRNA expression, criteria of Sepsis-3, internal reference of non-U6, and dysregulation expression of miR-223 had superior diagnostic accuracy. In addition, there was no significant publication bias among the included studies. Fagan’s nomogram showed valuable clinical utility.

Conclusions

Our meta-analysis indicated that the level of circulating miRNAs, particularly the miR-223, could be used as an indicator for sepsis.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s40560-020-00497-6.

The Septic Patient

Anesthesiologists are uniquely positioned to facilitate emergent care of patients with sepsis in the perioperative setting. A subset of sepsis patients presents with surgical pathology. Emphasis is on timely intervention with source control, antibiotic therapy, and aggressive resuscitation. Ileus, aspiration, and cardiovascular collapse must be considered when inducing patients with sepsis. Dynamic fluid responsiveness may prove an effective tool in minimizing over-resuscitation. Assessment of circulatory failure and drug therapy involves an understanding of preload, afterload, and contractility. Timely, targeted resuscitation and early source control have persisted and remain fundamental to sepsis care.

Inhibition of CXCR4 and CXCR7 Is Protective in Acute Peritoneal Inflammation

Our previous studies revealed a pivotal role of the chemokine stromal cell-derived factor (SDF)-1 and its receptors CXCR4 and CXCR7 on migratory behavior of polymorphonuclear granulocytes (PMNs) in pulmonary inflammation. Thereby, the SDF-1-CXCR4/CXCR7-axis was linked with adenosine signaling. However, the role of the SDF-1 receptors CXCR4 and CXCR7 in acute inflammatory peritonitis and peritonitis-related sepsis still remained unknown. The presented study provides new insight on the mechanism of a selective inhibition of CXCR4 (AMD3100) and CXCR7 (CCX771) in two models of peritonitis and peritonitis-related sepsis by injection of zymosan and fecal solution. We observed an increased expression of SDF-1, CXCR4, and CXCR7 in peritoneal tissue and various organs during acute inflammatory peritonitis. Selective inhibition of CXCR4 and CXCR7 reduced PMN accumulation in the peritoneal fluid and infiltration of neutrophils in lung and liver tissue in both models. Both inhibitors had no anti-inflammatory effects in A_2B knockout animals (A_2B–/–). AMD3100 and CCX771 treatment reduced capillary leakage and increased formation of tight junctions as a marker for microvascular permeability in wild type animals. In contrast, both inhibitors failed to improve capillary leakage in A_2B–/– animals, highlighting the impact of the A_2B-receptor in SDF-1 mediated signaling. After inflammation, the CXCR4 and CXCR7 antagonist induced an enhanced expression of the protective A_2B adenosine receptor and an increased activation of cAMP (cyclic adenosine mono phosphate) response element-binding protein (CREB), as downstream signaling pathway of A_2B. The CXCR4- and CXCR7-inhibitor reduced the release of cytokines in wild type animals via decreased intracellular phosphorylation of ERK and NFκB p65. In vitro, CXCR4 and CXCR7 antagonism diminished the chemokine release of human cells and increased cellular integrity by enhancing the expression of tight junctions. These protective effects were linked with functional A_2B-receptor signaling, confirming our in vivo data. In conclusion, our study revealed new protective aspects of the pharmacological modulation of the SDF-1-CXCR4/CXCR7-axis during acute peritoneal inflammation in terms of the two hallmarks PMN migration and barrier integrity. Both anti-inflammatory effects were linked with functional adenosine A_2B-receptor signaling.

The use of procalcitonin for the management of sepsis in Internal Medicine wards: current evidence

Procalcitonin (PCT) is a circulating polypeptide produced in response to bacterial infections. Studies conducted in the Intensive Care Unit (ICU) setting have demonstrated its utility as a biomarker of bacterial infection and sepsis. Thus, PCT is widely used to distinguish between sepsis and SIRS, and to guide antibiotic therapy. At present sepsis represents a frequent diagnosis among patients admitted to internal medicine (IM) departments. Basing on the knowledge derived from ICU studies, the use of PCT has become routine in non-intensive wards, contributing to improve the management of sepsis. However, some differences between the two populations of patients - the IM being older, affected by multiple chronic comorbidities and lacking of invasive monitoring - could limit the generalizability of ICU results. Most of the studies on PCT conducted in the IM setting have focused on chronic obstructive pulmonary disease, pneumonia and sepsis. Although PCT represents one of the best biomarker available in routine clinical practice, there are uncertainties on the optimal cut-offs to be used for starting or discontinuing antibiotic treatment in patients with suspected bacterial infection or sepsis, for predicting outcome and on the role of PCT variations during antibiotic treatment. Moreover, several diseases can produce an elevation of PCT levels, thus producing false positive results. This represents a narrative review summarizing current evidences on PCT for the management of sepsis in an Internal Medicine wards, highlighting differences with ICU, with a special focus on the role of PCT variations as predictor of outcomes in non-ICU wards.

The Pathogenesis of Sepsis and Potential Therapeutic Targets

Sepsis is defined as “a life-threatening organ dysfunction caused by a host’s dysfunctional response to infection”. Although the treatment of sepsis has developed rapidly in the past few years, sepsis incidence and mortality in clinical treatment is still climbing. Moreover, because of the diverse manifestations of sepsis, clinicians continue to face severe challenges in the diagnosis, treatment, and management of patients with sepsis. Here, we review the recent development in our understanding regarding the cellular pathogenesis and the target of clinical diagnosis of sepsis, with the goal of enhancing the current understanding of sepsis. The present state of research on targeted therapeutic drugs is also elaborated upon to provide information for the treatment of sepsis.