Response Sepsis Research Articles

Impacts of Curcumin Treatment on Experimental Sepsis: A Systematic Review.

Sepsis is defined as a life-threatening organ dysfunction due to a dysregulated host immune response to an infection. Curcumin is a yellow polyphenol derived from the rhizome of Curcuma longa with anti-inflammatory and antioxidant properties scientifically proven, a condition that allowed its use as a tool in the treatment of sepsis. Thus, the purpose of this article was to systematically review the evidence on the impact of curcumin's anti-inflammatory effect on experimental sepsis. For this, the PubMed, MEDLINE, EMBASE, Scopus, Web of Science, and LILACS databases were used, and the research was not limited to a specific publication period. Only original articles in English using in vivo experimental models (rats or mice) of sepsis induction performed by administration of lipopolysaccharide (LPS) or cecal ligation and perforation surgery (CLP) were included in the study. Studies using curcumin in dry extract or with a high degree of purity were included. At initial screening, 546 articles were selected, and of these, 223 were eligible for primary evaluation. Finally, 12 articles with full text met all inclusion criteria. Our results showed that curcumin may inhibit sepsis-induced complications such as brain, heart, liver, lungs, and kidney damage. Curcumin can inhibit inflammatory factors, prevent oxidative stress, and regulate immune responses in sepsis. Additionally, curcumin increased significantly the survival rates after experimental sepsis in several studies. The modulation of the immune response and mortality by curcumin reinforces its protective effect on sepsis and indicates a potential therapeutic tool for the treatment of sepsis.

Gram-negative bacterial infection causes aggravated innate immune response in sepsis: Studies from clinical samples and cellular models

Bacterial infection is the most common cause for sepsis. The purpose of this study was to evaluate the impact of different bacterial infection on sepsis based on human samples and cellular experiments. Physiological indexes and prognostic information of 121 sepsis patients were analysed based on whether they had a gram-positive or gram-negative bacterial infection. Moreover, murine RAW264.7 macrophages were treated with lipopolysaccharide (LPS) or peptidoglycan (PG) to simulate infection with gram-negative or gram-positive bacteria in sepsis, respectively. Exosomes derived from the macrophages were extracted for transcriptome sequencing. In patients with sepsis, most gram-positive bacterial infections were Staphylococcus aureus, and gram-negative infections were Escherichia coli. Gram-negative bacterial infection was significantly associated with high neutrophil and interleukin (IL)-6 levels in blood and shorter prothrombin (PT) and activated partial thromboplastin time (APTT). Intriguingly, the survival prognosis of sepsis patients was not affected by the type of bacterial infection, but it was significantly related to fibrinogen. Protein transcriptome sequencing of the macrophage-derived exosomes showed that differentially expressed proteins were significantly enriched in megakaryocyte differentiation, leukocyte and lymphocyte-mediated immunity, and complement and coagulation cascade pathways. The complement and coagulation-related proteins were significantly upregulated after LPS induction, which explained the shortened PT and APTT in gram-negative bacterial sepsis. Bacterial infection did not affect mortality in sepsis but did alter the host response. The immune disorder induced by gram-negative infection was more severe than that produced by gram-positive infection. This study provides references for the rapid identification and molecular research of different bacterial infections in sepsis.

Neuraminidase is a host-directed approach to regulate neutrophil responses in sepsis and COVID-19.

Neutrophil overstimulation plays a crucial role in tissue damage during severe infections. Because pathogen-derived neuraminidase (NEU) stimulates neutrophils, we investigated whether host NEU can be targeted to regulate the neutrophil dysregulation observed in severe infections. The effects of NEU inhibitors on lipopolysaccharide (LPS)-stimulated neutrophils from healthy donors or COVID-19 patients were determined by evaluating the shedding of surface sialic acids, cell activation, and reactive oxygen species (ROS) production. Re-analysis of single-cell RNA sequencing of respiratory tract samples from COVID-19 patients also was carried out. The effects of oseltamivir on sepsis and betacoronavirus-induced acute lung injury were evaluated in murine models. Oseltamivir and zanamivir constrained host NEU activity, surface sialic acid release, cell activation, and ROS production by LPS-activated human neutrophils. Mechanistically, LPS increased the interaction of NEU1 with matrix metalloproteinase 9 (MMP-9). Inhibition of MMP-9 prevented LPS-induced NEU activity and neutrophil response. In vivo, treatment with oseltamivir fine-tuned neutrophil migration and improved infection control as well as host survival in peritonitis and pneumonia sepsis. NEU1 also is highly expressed in neutrophils from COVID-19 patients, and treatment of whole-blood samples from these patients with either oseltamivir or zanamivir reduced neutrophil overactivation. Oseltamivir treatment of intranasally infected mice with the mouse hepatitis coronavirus 3 (MHV-3) decreased lung neutrophil infiltration, viral load, and tissue damage. These findings suggest that interplay of NEU1-MMP-9 induces neutrophil overactivation. In vivo, NEU may serve as a host-directed target to dampen neutrophil dysfunction during severe infections.

Citrulline enteral administration markedly reduces immunosuppressive extrafollicular plasma cell differentiation in a preclinical model of sepsis.

The sustained immunosuppression associated with severe sepsis favors an increased susceptibility to secondary infections and remains incompletely understood. Plasmablast and plasma cell subsets, whose primary function is to secrete antibodies, have emerged as important suppressive populations that expand during sepsis. In particular, sepsis supports CD39hi plasmablast metabolic reprogramming associated with adenosine-mediated suppressive activity. Arginine deficiency has been linked to an increased risk of secondary infections in sepsis. Overcoming arginine shortage by citrulline administration efficiently improves sepsis-induced immunosuppression and secondary infections in the cecal ligation and puncture murine model. Here, we aimed to determine the impact of citrulline administration on B cell suppressive responses in sepsis. We demonstrate that restoring arginine bioavailability through citrulline administration markedly reduces the dominant extrafollicular B cell response, decreasing the immunosuppressive LAG3+ and CD39+ plasma cell populations, and restoring splenic follicles. At the molecular level, the IRF4/MYC-mediated B cell reprogramming required for extrafollicular plasma cell differentiation is shunted in the splenic B cells of mice fed with citrulline. Our study reveals a prominent impact of nutrition on B cell responses and plasma cell differentiation and further supports the development of citrulline-based clinical studies to prevent sepsis-associated immune dysfunction.

Keyword Analysis: Identifying Interdisciplinary Improvement Opportunities for Sepsis Response

Background: Boston Children’s Hospital has implemented an enterprise-wide sepsis initiative to manage pediatric sepsis, one of the leading causes of mortality in pediatrics.1 To sustain and improve early sepsis identification and treatment, ongoing review of our process and outcomes data highlighted system gaps focusing on interdisciplinary communication and engagement at the bedside. Objectives: We conducted a qualitative assessment for 4 inpatient medicine units with nurses, attendings, residents, and NPs to understand pain points for escalation of concerns and communication methods among the caregivers and inform enterprise-level problem-solving. Methods: We conducted 16 focus group discussions with nurses, candy round interviews with 11 attending physicians, and surveys for 3 nurse practitioners and 47 resident physicians. Over 6 weeks, we collected 406 unique responses across all of our interactions. We then identified basic themes for interdisciplinary improvement in each phase of sepsis recognition and response. We executed a keyword analysis to quantitatively evaluate the responses and highlight opportunities for improvement. Figure 1 illustrates the keywords used in analysis. These specific keywords were identified most frequently throughout our initial thematic analysis. For instance, in our focus group discussions, Orderset and STAT popped up 16 and 20 times, respectively, when evaluating individual responses. We then used Excel’s Wildcard Function to search for multiple keywords at a time from each phase in our sepsis response. This function allowed us to analyze multiple keywords related to each phase of sepsis recognition and response.Fig. 1.: Keywords identified and utilized during data analysis.Results: Figure 2 highlights the improvement themes identified for different phases of sepsis clinical workflow for nurses and prescribers. We identified that the phases of highest uncertainty were during the sepsis huddle, plan of care, and ordering of antibiotics. We noted that in these stages of the care process, our keyword analysis pointed to a limited understanding in the sepsis huddle, lack of communication regarding IV access, and underutilization of our sepsis orderset as areas for improvement. Consequentially, we were able to develop improvement themes based on a Pareto chart developed from the frequency distribution of our keywords.Fig. 2.: Phases identified with opportunities for improvement. *Note that 116 responses for nurses and 24 responses from Residents, Attendings and NPs fell into miscellaneous categories that were not used in developing interventions.Conclusions: The keyword analysis helped illustrate the interaction of human behavior, technology, and working environments influencing our interdisciplinary workflows surrounding sepsis response. With data as our driver, we partnered with the frontline staff to develop and operationalize our new huddle checklist, IV algorithm triage resource, and sepsis orderset while continuing to monitor both our process and outcome measures. The result was a continuous increase in sepsis bundle utilization for critical sepsis patients with a center line shift from 41% to 70%. One of our biggest drivers of this shift was the centerline shift in sepsis orderset utilization increase from 36% to 61% across all sepsis patients. Finally, in response to our results, we are also working diligently to develop a simulation experience focusing on the huddle process. ACKNOWLEDGMENTS Monica Kleinman, MD, Medical/Surgical Intensive Care, Boston Children’s Hospital; Matthew Eisenberg, MD, Division of Emergency Medicine, Boston Children’s Hospital; Daniel Kelly, MD, Division of Medicine Critical Care, Boston Children’s Hospital; Kate Madden, MD, Medical/Surgical Intensive Care, Boston Children’s Hospital; Teresa Shannon, MSN, RN, CPN; Sue Dixon, RN; and Marlena Smith-Millman, MPH.

Knockdown of histone deacetylase 9 attenuates sepsis-induced myocardial injury and inflammatory response.

Myocardial cell damage is associated with apoptosis and excessive inflammatory response in sepsis. Histone deacetylases (HDACs) are implicated in the progression of heart diseases. This study aims to explore the role of histone deacetylase 9 (HDAC9) in sepsis-induced myocardial injury. Lipopolysaccharide (LPS)-induced Sprague Dawley rats and cardiomyocyte line H9C2 were used as models in vivo and in vitro. The results showed that HDAC9 was significantly upregulated after LPS stimulation, and HDAC9 knockdown remarkably improved cardiac function, as evidenced by decreased left ventricular internal diameter end diastole (LVEDD) and left ventricular internal diameter end systole (LVESD), and increased fractional shortening (FS)% and ejection fraction (EF)%. In addition, HDAC9 silencing alleviated release of inflammatory cytokines (tumor necrosis factor-α (TNF-α), IL-6 and IL-1β) and cardiomyocyte apoptosis in vivo and in vitro. Furthermore, HDAC9 inhibition was proved to suppress nuclear factor-kappa B (NF-κB) activation with reducing the levels of p-IκBα and p-p65, and p65 nuclear translocation. Additionally, interaction between miR-214-3p and HDAC9 was determined through bioinformatics analysis, RT-qPCR, western blot and dual luciferase reporter assay. Our data revealed that miR-214-3p directly targeted the 3'UTR of HDAC9. Our findings demonstrate that HDAC9 suppression ameliorates LPS-induced cardiac dysfunction by inhibiting the NF-κB signaling pathway and presents a promising therapeutic agent for the treatment of LPS-stimulated myocardial injury.

Role of the regulation of mesenchymal stem cells on macrophages in sepsis.

Sepsis is a common clinical critical disease with high mortality. The excessive release of cytokines from macrophages is the main cause of out-of-control immune response in sepsis. Mesenchymal stem cells (MSCs) are thought to be useful in adjunctive therapy of sepsis and related diseases, due to their function in immune regulation, anti-inflammatory, antibacterial, and tissue regeneration. Also there have been several successful cases in clinical treatment. Some previous studies have shown that MSCs regulate the function of macrophages through secreting cytokines and extracellular vesicles, or transferring mitochondria directly to target cells, which affects the progress of sepsis. Here, we review the regulation of MSCs on macrophages in sepsis, mainly focus on the regulation ways. We hope that will help to understand the immunological mechanism and also provide some clues for the clinical application of MSCs in the biotherapy of sepsis.

How Extracellular Nano-Vesicles Can Play a Role in Sepsis? An Evidence-Based Review of the Literature.

Sepsis is a systemic inflammatory reaction caused by infection. Severe sepsis can lead to multiple organ dysfunction, with a high incidence rate and mortality. The molecular pathogenesis of sepsis is complex and diverse. In recent years, with further study of the role of extracellular vesicles (EVs) in inflammatory diseases, it has been found that EVs play a dual role in the imbalance of inflammatory response in sepsis. Due to the great advantages such as lower toxicity, lower immunogenicity compared with stem cells and better circulation stability, EVs are increasingly used for the diagnosis and treatment of sepsis. The roles of EVs in the pathogenesis, diagnosis and treatment of sepsis were summarized to guide further clinical studies.

Development and validation of liquid chromatography-tandem mass spectrometry method to quantify dasatinib in plasma and its application to a pharmacokinetic study

Dasatinib, a potent oral multi-targeted kinase inhibitor against Src and Bcr-Abl, can decrease inflammatory response in sepsis. A simple and cost-effective method for determination of an effective dose dasatinib was established. This method was validated in human plasma, with the aim of reducing the number of animals used, thus, avoiding ethical problems. Dasatinib and internal standard lopinavir were extracted from 180 uL of plasma using liquid-liquid extraction with methyl tert-butil ether, followed by liquid chromatography coupled to triple quadrupole mass spectrometry in multiple reaction monitoring mode. For the pharmacokinetic study, 1 mg/kg of dasatinib was administered to mice with and without sepsis. The method was linear over the concentration range of 1-98 ng/mL for DAS in mice and human plasma, with r2>0.99 and presented intra- and interday precision within the range of 2.3 - 6.2 and 4.3 - 7.0%, respectively. Further intra- and interday accuracy was within the range of 88.2 - 105.8 and 90.6 - 101.7%, respectively. The mice with sepsis showed AUC0-t = 2076.06 h*ng/mL and Cmax =102.73 ng/mL and mice without sepsis presented AUC0-t = 2128.46 h*ng/mL. Cmax = 164.5 ng/mL. The described analytical method was successfully employed in pharmacokinetic study of DAS in mice.

May Pentoxifylline Protect Immature Brain Against Disorders Induced By Inflammatory Response In Neonatal Sepsis?

Prematurity is a chronic hyperinflammatory state when compared to the inflammatory response in adulthood. Even in the absence of disease, the inflammatory reaction is more robust with preterm infants mounting cytokine levels that far exceed those in adults with similar insults. Unregulated inflammatory response is partially due to an increase in production of proinflammatory mediators but is also due to the lack of negative regulator [1].

Effects of artemisinin and hydroxychloroquine on cytokines in experimental sepsis.

Pro-and anti-inflammatory cytokines mediate the inflammatory response in sepsis. Therefore, regulation of cytokines with medications in risky situations may protect the patients from sepsis. Hydroxychloroquine and artemisinin are antimalarial drugs with immunomodulatory properties. In this study, we intended to investigate the effects of artemisinin and hydroxychloroquine on the cytokines released during sepsis in the rat model. Twenty-four rats were randomized into four groups. The control group received oral saline, the sepsis group received oral saline and intraperitoneal lipopolysaccharide toxin (LPS), the artemisinin-treated sepsis group received oral 33.33 mg/kg of artemisinin, and the hydroxychloroquinetreated sepsis group received oral 33.33 mg/kg of hydroxychloroquine before LPS injection. Three hours later, serum cytokines were measured. An increase was detected in TNF-a, IL-1, and IL-6 levels in the sepsis group compared to the control (p<0.01). Oral pretreatment with artemisinin resulted in significant downregulation only of IL-1 levels (p<0.01). Cytokines IL-1 and IL-6 were significantly downregulated in the serum of LPS-induced rats pretreated with oral hydroxychloroquine than rats with sepsis (p<0.01). Decreases observed in TNF-a and IL-10 levels were insignificant. These results demonstrated that both artemisinin and hydroxychloroquine attenuate the release of pro-inflammatory cytokines three hours after LPS-induced sepsis in rats. A significant decrease was observed in serum IL-1 and IL-6 levels with hydroxychloroquine and IL-1 levels with artemisinin. Based on our findings, we suggest that the therapeutic potential of artemisinin and hydroxychloroquine may be beneficial in preventing cytokine storm during sepsis, and further research is needed to determine the optimal timing of administration.

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

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

A Rare Presentation of Fulminant Toxic Shock Syndrome in a Healthy 10-Year-Old Male Patient

Staphylococcal toxic shock syndrome (STSS) is characterized by acute, progressive illness with fever, rapid-onset hypotension, and multisystem organ failure. The clinical course of STSS is attributable to host response to exotoxins with superantigenic properties. Fulminant staphylococcal infection is often associated with a deep focus of infection. In this report, we present a 10-year-old boy with multisystem organ failure as a result of STSS, a rare fatal complication following soft tissue injury. The rapid and fulminant progression of the disease in our patient precluded early timely diagnosis of STSS that may have allowed for the initiation of life-saving supportive intervention. Furthermore, the rapidly developing STSS occurred without an identifiable infectious source. The diagnosis of STSS was made upon the sum total of the clinical presentation, laboratory and autopsy findings, and antemortem and postmortem microbiology studies. It is crucial for health care providers to be aware of the possibility of STSS, even in the absence of overt focal infections and risk factors. A high index of suspicion for STSS should be present in critically ill patients presenting with a precipitous course of sepsis, septic shock, or systemic inflammatory response syndrome (SIRS).

Biomaterial mediated simultaneous delivery of spermine and alpha ketoglutarate modulate metabolism and innate immune cell phenotype in sepsis mouse models

Although different metabolic pathways have been associated with distinct macrophage phenotypes, the field of utilizing metabolites to modulate macrophage phenotype is in a nascent stage. In this report, we developed microparticles based on polymerization of alpha-ketoglutarate (a Krebs cycle metabolite), with or without encapsulation of spermine (a polyamine metabolite), to modulate cell phenotype that are critical for resolution of inflammation. Poly (alpha-ketoglutarate) microparticles encapsulated and released spermine (spermine (encap)paKG MPs) in vitro, which was accelerated in an acidic environment. When delivered to bone marrow-derived-macrophages, spermine (encap)paKG MPs induced a complex phenotypic profile outside of the typical M1/M2 paradigm, with distinct effects in the presence or absence of the pro-inflammatory stimulus lipopolysaccharide. Of particular interest was the increase in expression of CD163, which has been linked to anti-inflammatory responses in sepsis. Therefore, we systemically administered spermine (encap)paKG MPs to two different murine models of sepsis using acute or chronic injection of LPS. Macrophages and neutrophils in the liver and spleen of animals treated with spermine (encap)paKG MPs increased expression of CD163, concomitant with normalizing of glycolysis and oxidative phosphorylation, in both models. Overall, these results show that spermine (encap)paKG MPs modulate macrophage phenotype in vitro and in vivo, with potential applications in inflammation-associated diseases.

The Predictive Value of Systemic Immune-Inflammation Index and Symptom Severity Score for Sepsis and Systemic Inflammatory Response Syndrome in Odontogenic Infections.

Acute Odontogenic Infections (OI) are the leading cause of emergency visits and hospitalizations to the maxillofacial department, and may induce systemic inflammatory complications. Increasing numbers of OI patients need extended hospitalizations, various treatments, and intensive care. The Symptom Severity score (SS) helps doctors assess the likelihood of infection and admission complications. Systemic Immune-inflammation Index (SII) is a biomarker-based inflammatory prognosis score. It was hypothesized that greater SII and SS values might suggest a higher risk for sepsis and systemic inflammatory response syndrome (SIRS). Therefore, this research aims to discover whether SII and SS scores can reliably predict odontogenic infection severity and prognosis, and if they can be used to predict the development of SIRS and sepsis in OI using admission features. The study was designed as a retrospective cohort, with patients' data being retrieved from medical records between January 2017 to April 2022. A total of 108 OI patients were matched 1:1 as low-severity and high-severity groups. Most individuals with severe infections had diabetes and smoking as comorbidities. Severe patients had longer hospital stays (12.0 days vs. 4.1 days), although mortality rates did not significantly differ. A total of 11.1% lower-severity patients (Group A) had SIRS during hospitalization, compared to Group B with 25.9%. Group A had 7.4% of patients that developed sepsis compared to Group B's rate of 22.2%. The correlation between OI's SS and SII index values was positive and statistically significant (r = 0.6314). The total SII index mean was 1303, whereas the mean values by severity were 696.3 in Group A and 2312.4 in Group B. Group A's mean SS score was 6.1, while Group B's was 13.6. According to the calculated AUC plots, SII and SS scores were accurate predictors of sepsis and SIRS development using OI admission parameters. The adjusted odds ratio for SIRS in OI patients was 2.09, and 2.27 for sepsis. Medical professionals and dentistry teams should be encouraged to use the SII and SS scores to diagnose and anticipate sepsis and SIRS, hence improving disease management decisions.

THE ROLE OF OBESITY AND PLASMA ADIPOCYTOKINES IN IMMUNE DYSREGULATION IN SEPSIS PATIENTS.

Introduction: The dysregulated immune response in sepsis is highly variable, ranging from hyperinflammation to immunoparalysis. Obesity is associated with the release of inflammatory mediators from adipose tissue, known as adipocytokines, causing a chronic inflammatory state. Perhaps counterintuitively, obesity is also associated with lower mortality in sepsis patients. We investigated the association between obesity, circulating adipocytokine concentrations, immune dysregulation, and outcome in sepsis patients. Methods In this secondary analysis of a prospective study, plasma concentrations of the adipocytokines leptin, adiponectin, and resistin were assessed in 167 patients at diagnosis of sepsis due to pneumonia, bacteremia, or acute cholangitis. Adipocytokines were compared between patients with normal weight (body mass index [BMI], 18.5-24.9 kg/m 2 ; n = 67), overweight (BMI, 25.0-29.9 kg/m 2 ; n = 56), and obesity (BMI ≥30 kg/m 2 ; n = 42), as well as between immunological endotypes: hyperinflammation (n = 40), immunoparalysis (n = 62), and unclassified (n = 55). Results: Higher circulating concentrations of leptin were observed in patients with obesity compared with patients with normal weight ( P = 0.008) and overweight ( P = 0.02), whereas adiponectin and resistin plasma concentrations were not different ( P = 0.08 and P = 0.85, respectively). Resistin concentrations were associated with immunological endotypes, with the highest levels found in hyperinflammatory patients ( P < 0.001). Furthermore, resistin concentrations were predictive for 28-day mortality (adjusted odds ratio, 1.03 per 10 ng/mL; P = 0.04). These associations were not found for leptin and adiponectin. Conclusion: Obesity and BMI-related adipocytokines are not related to the development of a hyperactive or suppressed immune response as defined by ferritin and mHLA-DR expression in sepsis patients. Although resistin is related to the immune response and an increased risk of adverse clinical outcomes, these associations are similar in patients with normal weight, overweight, and obesity. This implies that the relationship between resistin and clinical outcome is likely driven by the inflammatory response and not by obesity itself. Taken together, although there exists a strong association between inflammation and sepsis mortality, our results do not point toward a role for obesity and BMI-related adipocytokines in immune dysregulation in sepsis patients.

Construction and validation of a robust prognostic model based on immune features in sepsis.

Sepsis, with life-threatening organ failure, is caused by the uncontrolled host response to infection. Immune response plays an important role in the pathophysiology of sepsis. Immune-related genes (IRGs) are promising novel biomarkers that have been used to construct the diagnostic and prognostic model. However, an IRG prognostic model used to predict the 28-day mortality in sepsis was still limited. Therefore, the study aimed to develop a prognostic model based on IRGs to identify patients with high risk and predict the 28-day mortality in sepsis. Then, we further explore the circulating immune cell and immunosuppression state in sepsis. The differentially expressed genes (DEGs), differentially expressed immune-related genes (DEIRGs), and differentially expressed transcription factors (DETFs) were obtained from the GEO, ImmPort, and Cistrome databases. Then, the TFs-DEIRGs regulatory network and prognostic prediction model were constructed by Cox regression analysis and Pearson correlation analysis. The external datasets also validated the reliability of the prognostic model. Based on the prognostic DEIRGs, we developed a nomogram and conducted an independent prognosis analysis to explore the relationship between DEIRGs in the prognostic model and clinical features in sepsis. Besides, we further evaluate the circulating immune cells state in sepsis. A total of seven datasets were included in our study. Among them, GSE65682 was identified as a discovery cohort. The results of GSEA showed that there is a significant correlation between sepsis and immune response. Then, based on a P value <0.01, 69 prognostic DEIRGs were obtained and the potential molecular mechanisms of DEIRGs were also clarified. According to multivariate Cox regression analysis, 22 DEIRGs were further identified to construct the prognostic model and identify patients with high risk. The Kaplan-Meier survival analysis showed that high-risk groups have higher 28-day mortality than low-risk groups (P=1.105e-13). The AUC value was 0.879 which symbolized that the prognostic model had a better accuracy to predict the 28-day mortality. The external datasets also prove that the prognostic model had an excellent prediction value. Furthermore, the results of correlation analysis showed that patients with Mars1 might have higher risk scores than Mars2-4 (P=0.002). According to the previous study, Mars1 endotype was characterized by immunoparalysis. Thus, the sepsis patients in high-risk groups might exist the immunosuppression. Between the high-risk and low-risk groups, circulating immune cells types were significantly different, and risk score was significantly negatively correlated with naive CD4+ T cells (P=0.019), activated NK cells (P=0.0045), monocytes (P=0.0134), and M1 macrophages (P=0.0002). Our study provides a robust prognostic model based on 22 DEIRGs which can predict 28-day mortality and immunosuppression status in sepsis. The higher risk score was positively associated with 28-day mortality and the development of immunosuppression. IRGs are a promising biomarker that might facilitate personalized treatments for sepsis.

Monitoring the Host Immune Response in Sepsis

Abstract Sepsis is a life-threatening condition characterized by immune system dysregulation whose pathophysiology still remains incompletely understood. Better outcomes in patients with sepsis have not been reached despite guidelines updates, development of rapid diagnostic tests, and proper hemodynamic and antimicrobial management. Blood cultures are time-consuming and may delay important therapeutic decisions. Nonculture-based techniques overcome some limitations seen with culture-based techniques with early phenotypic identification of resistance remaining as the cornerstone of optimal diagnosis. A new paradigm has started adjusting preemptive therapy for cytomegalovirus (CMV) infection among kidney transplant patients based on monitoring the host immune response. In this review from a PubMed literature search in adults with sepsis or septic shock, we identified newer tests and highlight some advances in monitoring the host immune response for personalized adjunctive therapy. Monitoring the individual host immune response at the bedside is an unmet clinical need to guide immunomodulatory therapy. The coronavirus disease 2019 pandemic has led to a further understanding of the complex immunopathology of sepsis and opened new avenues for mitigating immune dysregulation. In this review, we discuss current evidence regarding the immune response to sepsis along with challenges and directions for future research.

Sepsis biomarkers and diagnostic tools with a focus on machine learning.

Over the last years, there have been advances in the use of data-driven techniques to improve the definition, early recognition, subtypes characterisation, prognostication and treatment personalisation of sepsis. Some of those involve the discovery or evaluation of biomarkers or digital signatures of sepsis or sepsis sub-phenotypes. It is hoped that their identification may improve timeliness and accuracy of diagnosis, suggest physiological pathways and therapeutic targets, inform targeted recruitment into clinical trials, and optimise clinical management. Given the complexities of the sepsis response, panels of biomarkers or models combining biomarkers and clinical data are necessary, as well as specific data analysis methods, which broadly fall under the scope of machine learning. This narrative review gives a brief overview of the main machine learning techniques (mainly in the realms of supervised and unsupervised methods) and published applications that have been used to create sepsis diagnostic tools and identify biomarkers.

Glucose metabolism is upregulated in the mononuclear cell proteome during sepsis and supports endotoxin-tolerant cell function.

Metabolic adaptations shape immune cell function. In the acute response, a metabolic switch towards glycolysis is necessary for mounting a proinflammatory response. During the clinical course of sepsis, both suppression and activation of immune responses take place simultaneously. Leukocytes from septic patients present inhibition of cytokine production while other functions such as phagocytosis and production of reactive oxygen species (ROS) are preserved, similarly to the in vitro endotoxin tolerance model, where a first stimulation with lipopolysaccharide (LPS) affects the response to a second stimulus. Here, we sought to investigate how cellular metabolism is related to the modulation of immune responses in sepsis and endotoxin tolerance. Proteomic analysis in peripheral blood mononuclear cells (PBMCs) from septic patients obtained at intensive care unit admission showed an upregulation of proteins related to glycolysis, the pentose phosphate pathway (PPP), production of ROS and nitric oxide, and downregulation of proteins in the tricarboxylic acid cycle and oxidative phosphorylation compared to healthy volunteers. Using the endotoxin-tolerance model in PBMCs from healthy subjects, we observed increased lactate production in control cells upon LPS stimulation, while endotoxin-tolerant cells presented inhibited tumor necrosis factor-α and lactate production along with preserved phagocytic capacity. Inhibition of glycolysis and PPP led to impairment of phagocytosis and cytokine production both in control and in endotoxin-tolerant cells. These data indicate that glucose metabolism supports leukocyte functions even in a condition of endotoxin tolerance.