Sepsis-induced immunosuppression: mechanisms, diagnosis and current treatment options

Targeting sepsis through inflammation and oxidative metabolism

Infection is a public health problem and represents a spectrum of disease that can result in sepsis and septic shock. Sepsis is characterized by a dysregulated immune response to infection. Septic shock is the most severe form of sepsis which leads to distributive shock and high mortality rates. There have been significant advances in sepsis management mainly focusing on early identification and therapy. However, complicating matters is the lack of reliable diagnostic tools and the poor specificity and sensitivity of existing scoring tools i.e., systemic inflammatory response syndrome criteria, sequential organ failure assessment (SOFA), or quick SOFA. These limitations have underscored the modest progress in reducing sepsis-related mortality. This review will focus on novel therapeutics such as oxidative stress targets, cytokine modulation, endothelial cell modulation, etc., that are being conceptualized for the management of sepsis and septic shock.

XueBiJing injection improves the symptoms of sepsis-induced acute lung injury by mitigating oxidative stress and ferroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

XBJ injection is approved by the China Food and Drug Administration for the adjunctive treatment of sepsis, and it is derived from the traditional Chinese medicine (TCM) prescription XuefuZhuyu Decoction. It consists of five Chinese herbal extracts: Carthamus tinctorius, Paeonia lactiflora, Salvia miltiorrhiza, Conioselinum anthriscoides 'Chuanxiong' and Angelica sinensis.

AIM OF THE STUDY

The purpose of this study was to explore the relationship between ferroptosis and acute septic lung injury, and to evaluate the improvement effect of XBJ injection on acute lung injury in sepsis.

MATERIALS AND METHODS

Acute lung injury was induced in rats by cecum ligation and puncture, and these rats were treated with XBJ injection. Oxidative stress and inflammation levels were assessed in serum and lung tissue, and tissue samples were collected for histological and protein analyses. To illustrate the mechanism of the improvement effect of XBJ on acute lung injury in sepsis, serum lipidomics was carried out to investigate whether XBJ prevents oxidative stress-induced lipid metabolism disorders. Furthermore, protein expression of ferroptosis-related genes was also examined.

RESULTS

XBJ was shown to be effective in alleviating sepsis-induced ALI. XBJ also improves sepsis-induced acute lung injury by reducing lipid peroxidation and inflammation and modulating ferroptosis pathways. Specifically, compared with the sham group, XBJ downregulated the levels of Fe2+, MDA and GSSG, and reversed the decrease in the levels of GSH and GSH/GSSH in lung tissue. Metabolic pathways such as glycerophospholipid metabolism, phospholipid metabolism, and lipid metabolism associated with ferroptosis were obtained by lipidomic analysis of differential lipid metabolite enrichment, suggesting that ferroptosis occurs in septic rats, and that XBJ inhibits ferroptosis and thereby improves sepsis-induced ALI. Furthermore, XBJ optimises iron metabolism and lipid oxide metabolism by regulating the expression of a series of proteins that are closely related to ferroptosis, such as GPX4, ACSL4, x-CT, and FTH1.

CONCLUSIONS

Our findings, initially, indicated that XBJ ameliorates sepsis-induced ALI by reducing oxidative stress and ferroptosis, revealing a previously unrecognised mechanism by which XBJ ameliorates sepsis-induced ALI.

Evaluation of the protective role of resveratrol on LPS-induced septic intestinal barrier function via TLR4/MyD88/NF-κB signaling pathways

The intestinal barrier function is a critical defense mechanism in the human body, serving as both the primary target and initiating organ in cases of sepsis. Preserving the integrity of this barrier is essential for preventing complications and diseases, including sepsis and mortality. Despite this importance, the impact of resveratrol on intestinal barrier function remains unclear. Thus, this study aims to explore the potential beneficial effects of resveratrol on maintaining intestinal barrier function. Fifteen male Sprague Dawley rats, weighing between 180 g and 220 g, were randomly assigned to one of three groups: the control group (Con), the lipopolysaccharide (LPS) group, and the resveratrol (RSV) group. The resveratrol group received an intravenous administration of resveratrol at a dosage of 8 mg/kg, 10 min prior to lipopolysaccharide treatment. Each group comprised five rats. Various techniques including enzyme-linked immunosorbent assay (ELISA), hematoxylin and eosin staining (HE), periodic acid Schiff (PAS) staining, transmission electron microscopy (TEM), Western blot analysis (WB), and quantitative real-time polymerase chain reaction (qRT-PCR) were utilized to assess differences in inflammatory cytokine expression, histopathological changes, apoptosis, tight junction (TJ) protein, and the TLR4/MyD88/NF-кB signaling pathways. Resveratrol exhibited anti-inflammatory effects by decreasing levels of interleukin (IL)-1β, interleukin(IL)-6, and tumor necrosis factor (TNF)-α, while increasing interleukin (IL)-10. Additionally, in rats treated with resveratrol, there was a reduction in the expression of apoptosis-associated proteins Bax and Caspase-3. Resveratrol also significantly increased the expression of intestinal tight junction proteins (TJ), and decreased the levels of intestinal fatty acid binding protein (I-FABP) and D-lactic acid (D-LA). Furthermore, the expression of proteins in the related signaling pathways TLR4, MyD88, and NF-κB was decreased. Resveratrol has been shown to reduce the expression of intestinal apoptotic proteins, enhance the expression of intestinal tight junction proteins, and inhibit the inflammatory response mediated by the TLR4/MyD88/NF-κB signaling pathway, thereby alleviating LPS-induced septic intestinal injury.

Megakaryocyte in sepsis: the trinity of coagulation, inflammation and immunity

BACKGROUND

Megakaryocytes are traditionally recognized as cells responsible for platelet production. However, beyond their role in thrombopoiesis, megakaryocytes also participate in inflammatory responses and regulate immune system functions. Sepsis, characterized by life-threatening organ dysfunction due to a dysregulated response to infection, prominently features coagulopathy, severe inflammation, and immune dysfunction as key pathophysiological aspects.

AIM OF REVIEW

Given the diverse functions of megakaryocytes, we explore their roles in coagulation in the context of sepsis, and also in inflammatory and immune regulation. We try to infer future research directions and potential strategies for sepsis prevention and treatment based on the properties of megakaryocytes.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The purpose of this review is to both highlight and provide an update on the functions of megakaryocytes and pathophysiological changes in sepsis. Specific emphasis is given to the role of megakaryocytes in sepsis, which suggests value of future research and clinical application.

Nano Acacetin Mitigates Intestinal Mucosal Injury in Sepsis Rats by Protecting Mitochondrial Function and Regulating TRX1 to Inhibit the NLRP3 Pyroptosis Pathway

Background

Acacetin (AC) is a flavonoid compound with antiperoxidant, anti-inflammatory, and antiplasmodial activity. However, the solubility of AC is poor and nano acacetin (Nano AC) was synthesized. The intestinal mucosal barrier is impaired in sepsis rats, and the protective effects and mechanism of AC and Nano AC on the intestinal mucosal barrier are unclear.

Methods

Cecal ligation and perforation (CLP) was used to induce sepsis in rats, and lipopolysaccharide (LPS)-stimulated intestinal epithelial cells were used to observe the effects of AC and our synthesized Nano AC on the amelioration of intestinal mucosal damage. The molecular docking technique was used to predict the binding energy of AC to thioredoxin reductase 1 (TRX1) signaling pathway proteins. TRX1 inhibitor (PX-12) was employed to elucidate the protective signaling pathway of Nano AC in LPS-stimulated intestinal epithelial cells.

Results

Our synthesized Nano AC, with an average particle size of 17.18 ± 0.48 nm and an uptake rate of 95% in intestinal epithelial cells. The maximum binding capacity of AC to TRX1 was -6.82 kcal/mol, supporting the hypothesis that TRX1 is a potential target of AC. AC and Nano AC ameliorated the survival rate, intestinal mucosal damage score, pathological morphology, hepatic and renal function, and myocardial troponin levels, decreased serum levels of pyroptosis-related factors, upregulated TRX1, down-regulated NOD-like receptor protein 3 inflammasome (NLRP3), cysteinyl aspartate specific proteinase-11 (Caspase-11), Gasdermin D (GSDMD) in sepsis rats. They improved mitochondrial morphology and mitochondrial reactive oxygen species (ROS) levels, reduced pyroptosis levels, and upregulated TRX1, which adjusted NLRP3/ Caspase-11/ GSDMD signaling pathway in LPS-stimulated intestinal epithelial cells. Moreover, Nano AC was more effective.

Conclusion

AC and Nano-AC can inhibit the NLRP3/Caspase-11/GSDMD signaling pathway by upregulating TRX1 to ameliorate intestinal mucosal injury in sepsis rats, and the effect of Nano AC is more prominent.

Association between body temperature and all-cause mortality in patients with sepsis: analysis of the MIMIC-IV database

BACKGROUND

Abnormal body temperature (fever or hypothermia) is a critical symptom in sepsis and is strongly associated with clinical prognosis and disease progression. Given the duality and variability of body temperature fluctuations throughout the disease course, further research is essential to refine clinical strategies for temperature management in sepsis patients.

METHODS

We extracted clinical data of sepsis patients from the MIMIC-IV database. A restricted cubic spline (RCS) curve was employed to describe the non-linear relationship between body temperature and clinical outcomes. Based on peak temperature within the first 24 h after admission, patients were categorized into three groups: < 36 °C, 36-38 °C, and > 38 °C. We subsequently matched patients one-to-one into three cohorts using a pairwise propensity score matching (PSM) approach. Alongside clinical data, we conducted log-rank and McNemar tests, and established multiple models, including multiple Cox regression, overlap-weighted (OW) adjusted Cox regression, multiple logistic regression, and OW-adjusted multiple logistic regression, to investigate the impact of temperature on clinical outcomes.

RESULTS

A total of 35,499 sepsis patients were included in my study: 311 with a temperature below 36 °C, 27,538 with a temperature between 36 and 38 °C, and 7650 with a temperature above 38 °C. The RCS analysis revealed a non-linear, U-shaped relationship between body temperature and 28-day, ICU, and in-hospital mortality. Patients with hypothermia had significantly higher 28-day mortality (54.34% vs. 19.28%), ICU mortality (44.37% vs. 12.89%), and in-hospital mortality (49.20% vs. 17.46%) compared to those with hyperthermia. Among patients younger than 65 years, hyperthermia was a protective factor against 28-day mortality relative to normal body temperature, while the opposite was observed in patients aged 65 and older. This trend was consistent in the analysis of ICU and in-hospital mortality.

CONCLUSIONS

Among sepsis patients admitted to the ICU, a peak temperature below 36 °C within the first 24 h of admission was associated with higher 28-day mortality. However, no significant difference in clinical prognosis was observed between normothermic and hyperthermic patients.

Discovery of Novel MyD88 Inhibitor A5S to Alleviate Acute Lung Injury with Favorable Drug-like Properties

Myeloid differentiation primary response 88 (MyD88) plays a central role in inflammatory responses and diseases. However, only a few inhibitors of MyD88 with some limits have been reported currently. Herein, we identified a lead compound (L7) through virtual screening and synthesized twenty-seven L7 derivatives. An optimal compound (A5) was determined through enzyme-linked immunosorbent assay (ELISA), 2,5-diphenyl-2H-tetrazolium bromide (MTT), and biolayer interferometry (BLI) assay. The potent isomer A5S showed a high MyD88 binding ability and exerted an anti-inflammatory effect through the NF-κB/MAPK pathway. A5S had good stability and safety, showed the highest distribution concentration in the lungs, and exhibited good therapeutic effects on LPS-induced and sepsis-induced ALI mouse models. Most importantly, A5S showed advantages in PK properties, and was identified as a promising MyD88 inhibitor with favorable drug-like properties, compared to the only approved MyD88 inhibitor, TJ-M2010-5, which is currently undergoing a Phase I study, and our previously reported MyD88 inhibitors LM8.

The role of m6A methylation genes in predicting poor prognosis in sepsis: identifying key biomarkers and therapeutic targets

Sepsis is one of the leading causes of death among seriously ill patients worldwide, affecting more than 30 million people annually and accounting for 1-2% of hospitalizations. By analyzing gene expression omnibus (GEO) data set, our team explored the relationship between m6A methylation gene and poor prognosis of sepsis. The purpose of this present study is to examine new detection markers for patients with poor prognosis, provide theoretical basis for timely intervention and improve the survival rate of patients. First, GSE54514 transcriptome data were extracted from the GEO database 31 patients with sepsis related death and 72 sepsis survivors. Key genes were screened from differentially expressed genes (DEGs), least absolute shrinkage and selection operator (LSAAO) and random forest (RF). And then, METTL3, WTAP and RBM15 were further verified by quantitative reverse transcription PCR (qRT-PCR). The constructed nomogram model showed high accuracy in predicting death. These three genes are mainly involved in chemokine signaling pathway, differentiation of monocytes and T cells, and phagocytosis of immune cells. The analysis showed that a high m6A score subtype is linked to lower immunosuppression and higher survival rates in clinical samples, suggesting better immune responses and outcomes for these patients. Finally, the protective effect of METTL3 in sepsis was demonstrated in mouse sepsis model applied with METTL3 inhibitor, by conducting cell flow cytometry analysis, enzyme-linked immunosorbent assay (ELISA) and hematoxylin-eosin (HE) staining. In conclusion, these findings provide potential biomarkers and targets for early precision diagnosis and treatment.

Tim-3 pathway dysregulation and targeting in sepsis-induced immunosuppression

Sepsis is a major medical problem which causes millions of deaths worldwide every year. The host immune response in sepsis is characterized by acute inflammation and a simultaneous state of immunosuppression. In the later stage of sepsis, immunosuppression is a crucial factor that increases the susceptibility of septic patients to secondary infection and mortality. It is characterized by T cell exhaustion, excessive production of anti-inflammatory cytokines, hyperproliferation of immune suppressor cells and aberrant expression of immune checkpoint molecules. T cell immunoglobulin and mucin domain 3 (Tim-3), an immune checkpoint molecule, is found on the surface of various cells, including macrophages, NK cells, NKT cells, and T cells. There are four different ligands for Tim-3, and accumulating evidence indicates that Tim-3 and its ligands play a crucial role in regulating immune cell dysfunction during sepsis. Anti-Tim-3 antibodies have been applied in the field of cancer immunotherapy and have achieved positive therapeutic effects in some clinical trials. However, the therapeutic efficacy of Tim-3 blockade is still controversial in animal models of sepsis. These challenges highlight the need for a deeper understanding of Tim-3 signaling in sepsis. This review examines the comprehensive effect of Tim-3 signaling in the development of sepsis-induced immunosuppression and the therapeutic efficacy of Tim-3 blockade.

Copper-Based Nanoparticles for Effective Treatment Against Sepsis-Induced Lung Injury in Mice Model

Introduction

Lung injury, a common complication of sepsis, arises from elevated reactive oxygen species (ROS), mitochondrial dysfunction, and cell death driven by inflammation. In this study, a novel class of ultrasmall nanoparticles (Cu4.5O USNPs) was developed to address sepsis-induced lung injury (SILI).

Methods

The synthesized nanoparticles were thoroughly characterized to assess their properties. In vitro experiments were conducted to determine the biologically effective concentration and elucidate the anti-inflammatory mechanism of action. These findings were further supported by in vivo studies, showcasing the material's efficacy in mitigating SILI.

Results

The Cu4.5O USNPs demonstrated remarkable scavenging capabilities for hydrogen peroxide (H2O2), superoxide anions (O2 -), and hydroxyl radicals (·OH), attributed to their catalase (CAT)- and superoxide dismutase (SOD)-like activities. Additionally, the nanoparticles exhibited strong anti-inflammatory effects, preserved mitochondrial homeostasis through potent ROS scavenging, and significantly reduced cell death. In vivo studies on mice further validated their protective role against SILI.

The conclusion

This study highlights the therapeutic potential of Cu4.5O USNPs in treating sepsis-induced lung injury by effectively scavenging ROS and reducing cell death. These findings provide compelling evidence for the future use of copper-based nanoparticles as antioxidant therapeutics.

Clostridium butyricum, a future star in sepsis treatment

Sepsis is a systemic inflammatory response syndrome of multiorgan failure caused by dysregulation of the host response to infection and is a major cause of death in critically ill patients. In recent years, with the continuous development of sequencing technology, the intestinal microecology of this disease has been increasingly studied. The gut microbiota plays a host-protective role mainly through the maintenance of normal immune function and the intestinal barrier. Recent evidence suggests that intestinal flora dysbiosis plays a crucial role in sepsis. Clostridium butyricum (C. butyricum), which has been used as a probiotic in poultry feed since its discovery, has been found to play a potential protective role in intestinal infections, inflammatory bowel disease (IBD), colorectal cancer, and other diseases in recent studies. In this review, we continue to focus on the important role and mechanism of C. butyricum as a probiotic in human diseases, especially intestinal diseases. Additionally, we evaluate the research progress of C. butyricum in treatment of sepsis to identify more therapeutic targets for the clinical treatment of sepsis.

The impact of glucose metabolism on inflammatory processes in sepsis-induced acute lung injury

Acute lung injury (ALI) is a prevalent and critical complication of sepsis, marked by high incidence and mortality rates, with its pathogenesis still not being fully elucidated. Recent research has revealed a significant correlation between the metabolic reprogramming of glucose and sepsis-associated ALI (S-ALI). Throughout the course of S-ALI, immune cells, including macrophages and dendritic cells, undergo metabolic shifts to accommodate the intricate demands of immune function that emerge as sepsis advances. Indeed, glucose metabolic reprogramming in S-ALI serves as a double-edged sword, fueling inflammatory immune responses in the initial stages and subsequently initiating anti-inflammatory responses as the disease evolves. In this review, we delineate the current research progress concerning the pathogenic mechanisms linked to glucose metabolic reprogramming in S-ALI, with a focus on the pertinent immune cells implicated. We encapsulate the impact of glucose metabolic reprogramming on the onset, progression, and prognosis of S-ALI. Ultimately, by examining key regulatory factors within metabolic intermediates and enzymes, We have identified potential therapeutic targets linked to metabolic reprogramming, striving to tackle the inherent challenges in diagnosing and treating Severe Acute Lung Injury (S-ALI) with greater efficacy.

Unique lymphocyte transcriptomic profiles in septic patients with chronic critical illness

Introduction

Despite continued improvement in post-sepsis survival, long term morbidity and mortality remain high. Chronic critical illness (CCI), defined as persistent inflammation and organ injury requiring prolonged intensive care, is a harbinger of poor long-term outcomes in sepsis survivors. Current dogma states that sepsis survivors are immunosuppressed, particularly in CCI. Investigation of this immune suppression in heterogeneous immune populations across distinct clinical trajectories and outcomes, along with limited sampling access, is accessible via single-cell RNA sequencing (scRNA-seq).

Methods

scRNA-seq analysis was performed on healthy subjects (n=12), acutely septic patients at day 4 ± 1 (n=4), and those defined as rapid recovery (n=4) or CCI (n=5) at day 14-21. Differential gene expression and pathway analyses were performed on peripheral blood lymphocytes at both a population and annotated cell subset level. Cellular function was assessed via enzyme-linked immunosorbent spot (ELISpot), cytokine production analysis, and T-cell proliferation assays on an additional cohort of septic patients (19 healthy, 68 acutely septic, 27 rapid recovery and 20 classified as CCI 14-21 days after sepsis onset).

Results

Sepsis survivors that developed CCI exhibited proportional shifts within lymphoid cell populations, with expanded frequency of CD8+ and NK cells. Differential expression and pathway analyses revealed continued activation in T cells and NK cells, with generalized suppression of B-cell function. Both T and NK cell subsets displayed transcriptomic profiles of exhaustion and immunosuppression in CCI, particularly in CD8+ T effector memory (TEM) cells and NK cells. Functional validation of T-cell behavior in an independent cohort demonstrated T cells maintained proliferative responses in vitro yet exhibited a marked loss of cytokine production. IFN-γ production at the acute phase (day 4 ± 1) was significantly reduced in subjects later classified as CCI.

Discussion

Sepsis patients exhibit unique T-, B-, and NK-cell transcriptional patterns that are both time- and clinical trajectory-dependent. These transcriptomic and pathway differences in sepsis patients that develop CCI are associated with exhaustion in CD8+ TEM cells and NK cells. Understanding the specific immune system patterns of different cell subsets after sepsis at a molecular level will be key to the development of personalized immunotherapy and drug-targeting intervention.

Clinical trial registration

https://clinicaltrials.gov/, identifier NCT02276417.

N6-methyladenosine demethyltransferase FTO alleviates sepsis by upregulating BNIP3 to induce mitophagy

N6-methyladenosine (m6A) is known to be crucial in various biological processes, but its role in sepsis-induced circulatory and cardiac dysfunction is not well understood. Specifically, mitophagy, a specialized form of autophagy, is excessively activated during lipopolysaccharide (LPS)-induced myocardial injury. This study aimed to investigate the impact of LPS-induced endotoxemia on m6A-RNA methylation and its role in regulating mitophagy in sepsis-induced myocardial dysfunction. Our research demonstrated that FTO (fat mass and obesity-associated protein), an m6A demethylase, significantly affects abnormal m6A modification in the myocardium and cardiomyocytes following LPS treatment. In mice, cardiac dysfunction and cardiomyocyte apoptosis worsened after adeno-associated virus serotype 9 (AAV9)-mediated FTO knockdown. Further analyses to uncover the cellular mechanisms improving cardiac function showed that FTO reduced mitochondrial reactive oxygen species, restored both basal and maximal respiration, and preserved mitochondrial membrane potential. We revealed that FTO plays a critical role in activating mitophagy by targeting BNIP3. Additionally, the cardioprotective effects of AAV-FTO were significantly compromised by mdivi-1, a mitophagy inhibitor. Mechanistically, FTO interacted with BNIP3 transcripts and regulated their expression in an m6A-dependent manner. Following FTO silencing, BNIP3 transcripts with elevated m6A modification levels in their coding regions were bound by YTHDF2 (YT521-B homology m6A RNA-binding protein 2), leading to mRNA destabilization and decreased BNIP3 protein levels. These findings highlight the importance of FTO-dependent cardiac m6A methylation in regulating mitophagy and enhance our understanding of this critical interplay, which is essential for developing therapeutic strategies to protect cardiac mitochondrial function, alleviate cardiac dysfunction, and improve survival during sepsis.

Acupuncture Treats Sepsis through Immune Modulation and Organ Protection

Sepsis is a secondary condition resulting from severe systemic infections. It is a significant contributor to mortality in critically ill patients with rapid onset and severe symptoms. Acupuncture is a traditional Chinese medical treatment. Recent clinical studies have demonstrated that acupuncture, as an important synergistic therapy, has promising therapeutic effects in the treatment of sepsis. This paper reviews the mechanisms of immunomodulation and target organ protection associated with acupuncture and synergistic drug acupuncture in the treatment of sepsis. It also integrates existing studies to elucidate the modulation of the immune system and the protective effect of acupuncture on target organs.

Glucocorticoid therapy for sepsis in the AI era: a survey on current and future approaches

Sepsis, a life-threatening medical condition, manifests as new or worsening organ failures due to a dysregulated host response to infection. Many patients with sepsis have manifested a hyperinflammatory phenotype leading to the identification of inflammatory modulation by corticosteroids as a key treatment modality. However, the optimal use of corticosteroids in sepsis treatment remains a contentious subject, necessitating a deeper understanding of their physiological and pharmacological effects. Our study conducts a comprehensive review of randomized controlled trials (RCTs) focusing on traditional corticosteroid treatment in sepsis, alongside an analysis of evolving clinical guidelines. Additionally, we explore the emerging role of artificial intelligence (AI) in medicine, particularly in diagnosing, prognosticating, and treating sepsis. AI's advanced data processing capabilities reveal new avenues for enhancing corticosteroid therapeutic strategies in sepsis. The integration of AI in sepsis treatment has the potential to address existing gaps in knowledge, especially in the application of corticosteroids. Our findings suggest that combining corticosteroid therapy with AI-driven insights could lead to more personalized and effective sepsis treatments. This approach holds promise for improving clinical outcomes and presents a significant advancement in the management of this complex and often fatal condition.

Annexin A1 Mitigates Blood-Brain Barrier Disruption in a Sepsis-Associated Encephalopathy Model by Enhancing the Expression of Occludin and Zonula Occludens-1 (ZO-1)

AIMS

This study investigated the protective role of Annexin A1 (ANXA1) in sepsis-associated encephalopathy (SAE) by examining its effects on brain vascular endothelium and blood-brain barrier (BBB) integrity.

METHODS

Mice were divided into four groups: wild type (WT), cecal ligation and puncture (CLP), ANXA1 knockout (ANXA1[-/-]), and ANXA1(-/-) with CLP. Neurobehavioral changes were assessed using the Y-maze test, while BBB integrity was evaluated through Evans blue dye (EBD) staining and permeability tests with fluorescein isothiocyanate (FITC)-dextran.

RESULTS

Results showed that ANXA1 levels were reduced in septic mice, and its deficiency exacerbated cognitive impairment and survival rate reduction. ANXA1 deficiency also upregulated proinflammatory cytokines and adhesion molecules, worsened BBB impairment, and altered expression of tight junction proteins and VEGF-A/VEGF-R2. In vitro, ANXA1 Ac2-26 prevented LPS-induced increased permeability in bEnd.3 cells by restoring tight junction proteins and reducing VEGF-A/VEGF-R2 expression. Notably, VEGF-A negated the protective effects of ANXA1 Ac2-26.

CONCLUSION

The study concludes that ANXA1 reduces BBB permeability to protect against sepsis-induced brain dysfunction via VEGF-A/VEGF-R2 regulation of tight junction proteins, suggesting ANXA1 as a potential therapeutic for SAE.

Exosomes as novel biomarkers in sepsis and sepsis related organ failure

Sepsis, a severe and life-threatening condition arising from a dysfunctional host response to infection, presents considerable challenges to the health care system and is characterized by high mortality rates and substantial economic costs. Exosomes have garnered attention as potential diagnostic markers because of their capacity to mirror the pathophysiological milieu of sepsis. This discourse reviews the progression of sepsis classification from Sepsis 1.0 to Sepsis 3.0, highlighting the imperative for sensitive and specific biomarkers to facilitate timely diagnosis and optimize patient outcomes. Existing biomarkers, such as procalcitonin (PCT) and C-reactive protein (CRP), exhibit certain limitations, thereby prompting the quest for more dependable diagnostic indicators. Exosomal cargoes, which encompass proteins and miRNAs, present a trove of biomarker candidates, attributable to their stability, pervasive presence, and indicative nature of the disease status. The potential of exosomal biomarkers in the identification of sepsis-induced organ damage, including cardiomyopathy, acute kidney injury, and acute lung injury, is emphasized, as they provide real-time insights into cardiac and renal impairments. Despite promising prospects, hurdles persist in the standardization of exosome extraction and the need for extensive clinical trials to validate their efficacy. The combination of biomarker development and sophisticated exosome detection techniques represents a pioneering strategy in the realm of sepsis diagnosis and management, underscoring the significance of further research and clinical validation.

Immune regulation and organ damage link adiponectin to sepsis

Sepsis is a life-threatening syndrome characterized by organ dysfunction, resulting from an uncontrolled or abnormal immune response to infection, which leads to septicemia. It involves a disruption of immune homeostasis, marked by the release of Inflammatory factors and dysfunction of immune cells. Adiponectin is widely recognized as an anti-inflammatory mediator, playing a crucial role in regulating immune cell function and exerting protective effects on tissues and organs. However, the physiological role of adiponectin in septicemia remains unclear due to the condition's association with immune response dysregulation and organ damage. This study focuses on the potential relationship between adiponectin and excessive immune responses, along with organ injury in septicemia. Additionally, we investigate possible explanations for the observed discrepancies in adiponectin levels among critically ill or deceased patients compared to theoretical expectations, aiming to provide valuable insights for clinical diagnostics and therapeutic interventions in sepsis.

IL7R, GZMA and CD8A serve as potential molecular biomarkers for sepsis based on bioinformatics analysis

Purpose

Sepsis is an unusual systemic reaction to what is sometimes an otherwise ordinary infection, and it probably represents a pattern of response by the immune system to injury. However, the relationship between biomarkers and sepsis remains unclear. This study aimed to find potential molecular biomarkers, which could do some help to patients with sepsis.

Methods

The sepsis dataset GSE28750, GSE57065 was downloaded from the GEO database, and ten patients with or without sepsis from our hospital were admitted for RNA-seq and the differentially expressed genes (DEGs) were screened. The Metascape database was used for functional enrichment analysis and was used to found the differential gene list. Protein-protein interaction network was used and further analyzed by using Cytoscape and STRING. Logistic regression and Correlation analysis were used to find the potential molecular biomarkers.

Results

Taking the intersection of the three datasets yielded 287 differential genes. The enrichment results included Neutrophil degranulation, leukocyte activation, immune effectors process, positive regulation of immune response, regulation of leukocyte activation. The top 10 key genes of PPI connectivity were screened using cytoHubba plugin, which were KLRK1, KLRB1, IL7R, GZMA, CD27, PRF1, CD8A, CD2, IL2RB, and GZMB. All of the hub genes are higher expressed in health group of different databases. Logistic regression showed that IL7R, GZMA and CD8A proteins were analyzed and all of them were statistically significant. Correlation analysis showed that there was a statistically significant correlation between IL7R, GZMA and CD8A.

Conclusion

KLRK1, KLRB1, IL7R, GZMA, CD27, PRF1, CD8A, CD2, IL2RB, GZMB are key genes in sepsis, which associated with the development of sepsis. However, IL7R, GZMA and CD8A may serve as the attractively potential molecular biomarkers for sepsis.

Identification of a Susceptible and High-Risk Population for Postoperative Systemic Inflammatory Response Syndrome in Older Adults: Machine Learning-Based Predictive Model

BACKGROUND

Systemic inflammatory response syndrome (SIRS) is a serious postoperative complication among older adult surgical patients that frequently develops into sepsis or even death. Notably, the incidences of SIRS and sepsis steadily increase with age. It is important to identify the risk of postoperative SIRS for older adult patients at a sufficiently early stage, which would allow preemptive individualized enhanced therapy to be conducted to improve the prognosis of older adult patients. In recent years, machine learning (ML) models have been deployed by researchers for many tasks, including disease prediction and risk stratification, exhibiting good application potential.

OBJECTIVE

We aimed to develop and validate an individualized predictive model to identify susceptible and high-risk populations for SIRS in older adult patients to instruct appropriate early interventions.

METHODS

Data for surgical patients aged ≥65 years from September 2015 to September 2020 in 3 independent medical centers were retrieved and analyzed. The eligible patient cohort in the Third Affiliated Hospital of Sun Yat-sen University was randomly separated into an 80% training set (2882 patients) and a 20% internal validation set (720 patients). We developed 4 ML models to predict postoperative SIRS. The area under the receiver operating curve (AUC), F1 score, Brier score, and calibration curve were used to evaluate the model performance. The model with the best performance was further validated in the other 2 independent data sets involving 844 and 307 cases, respectively.

RESULTS

The incidences of SIRS in the 3 medical centers were 24.3% (876/3602), 29.6% (250/844), and 6.5% (20/307), respectively. We identified 15 variables that were significantly associated with postoperative SIRS and used in 4 ML models to predict postoperative SIRS. A balanced cutoff between sensitivity and specificity was chosen to ensure as high a true positive as possible. The random forest classifier (RF) model showed the best overall performance to predict postoperative SIRS, with an AUC of 0.751 (95% CI 0.709-0.793), sensitivity of 0.682, specificity of 0.681, and F1 score of 0.508 in the internal validation set and higher AUCs in the external validation-1 set (0.759, 95% CI 0.723-0.795) and external validation-2 set (0.804, 95% CI 0.746-0.863).

CONCLUSIONS

We developed and validated a generalizable RF model to predict postoperative SIRS in older adult patients, enabling clinicians to screen susceptible and high-risk patients and implement early individualized interventions. An online risk calculator to make the RF model accessible to anesthesiologists and peers around the world was developed.

Exploiting the Zebrafish Model for Sepsis Research: Insights into Pathophysiology and Therapeutic Potentials

Sepsis, a severe condition instigated by infections, continues to be a primary global cause of death, typified by systemic inflammation and advancing immune dysfunction. Comprehending the complex pathological processes that underlie sepsis is integral to the creation of efficacious treatments. Despite the inability of animal models to entirely reproduce the clinical intricacies related to sepsis, they are invaluable instruments for the exploration and development of therapeutic approaches. Within this context, the zebrafish model is particularly noteworthy due to its genetic tractability, transparency, and appropriateness for high-throughput screening of genetic mutants and therapeutic compounds. This scholarly review emphasizes the crucial role that the zebrafish disease model plays in enhancing our comprehension of sepsis, by exploring its applications in deciphering immune and inflammatory responses, evaluating the consequences of genetic alterations, and examining novel therapeutic agents. The Insights derived from zebrafish research not only augment our understanding of the underlying mechanisms of sepsis, but also possess considerable potential for the transference of these discoveries into clinical therapies, thus potentially transforming the approach to sepsis management. The objective of this scholarly article is to underscore the importance of zebrafish in the realm of biomedical research pertaining to sepsis, and to delineate forthcoming opportunities for utilizing this model in clinical applications.

Plasma neutrophil extracellular traps in patients with sepsis-induced acute kidney injury serve as a new biomarker to predict 28-day survival outcomes of disease

Background

There is currently no accurate, readily available, or validated biomarker for assessing disease severity and survival outcomes in sepsis-induced acute kidney injury (SAKI), which limits the ability to conduct effective therapeutic interventions. The neutrophil extracellular traps (NETs) may be involved in the pathophysiology of SAKI. The present study investigated the predictive value of plasma NETs for the survival outcome of patients with SAKI.

Methods

This observational study included 136 SAKI patients, all of whom underwent a 28-day follow-up. According to the follow-up records, SAKI patients were divided into two groups: the non-survivor group (60 subjects) and the survivor group (76 subjects). Blood samples were collected after the diagnosis of AKI to measure three NET markers and 12 inflammatory indices. Correlation analysis, logistic regression analysis, receiver operating characteristic curve analysis, and survival analysis were performed.

Results

Compared to survivors, non-survivors among SAKI patients exhibited significantly higher levels of three plasma NET markers (all p < 0.001). Meanwhile, in SAKI patients, plasma levels of NET markers were significantly associated with serum levels of inflammatory indices. Additionally, serum interleukin (IL)-2, IL-8, IL-10, and tumor necrosis factor-alpha showed an interactive effect with plasma NET markers on the survival of SAKI patients. Furthermore, the combination of three plasma NET markers could identify SAKI patients with a poor 28-day survival with better accuracy (area under the curve = 0.857). Finally, plasma NET markers may independently predict the 28-day survival in SAKI patients.

Conclusion

Plasma NET markers were elevated in SAKI patients with poor outcomes and served as biomarkers for predicting 28-day survival in SAKI patients.

Sepsis-associated liver injury: Mechanisms and potential therapeutic targets

In this editorial, we examined a recent article in the World Journal of Gastroenterology that focused on sepsis-associated liver injury (SLI) and its treatment. SLI is a serious complication of sepsis, primarily caused by microcirculatory disturbances, the gut-liver axis, and inflammatory responses. Specific treatment recommendations for SLI are lacking. The gut-liver axis represents a potential therapeutic target, with metformin showing promise in modulating the gut microbiome and enhancing intestinal barrier function. Although immunomodulatory therapies are being explored, anti-tumor necrosis factor agents and interleukin-1 receptor antagonists have not demonstrated significant clinical benefits. Statins may reduce liver inflammation and prevent injury in sepsis, but their clinical application is limited. Reduced D-related human leucocyte antigen expression on monocytes and lymphocytes suggests immune suppression in patients, indicating that corticosteroids could reverse clinical deterioration in severe infections and address adrenal cortical insufficiency. Current large-scale studies on glucocorticoid therapy for sepsis have yielded mixed results, likely due to inadequate assessment of the immune status of the host. Future research should prioritize the development of personalized immunotherapy tailored to patients' immune profiles, focusing on identifying novel indicators of immune status and advancing immunomodulatory targets and therapeutics for septic patients.

Predictive Value of the Systemic Immune-Inflammation Index in the 28-Day Mortality for Patients with Sepsis-Associated Acute Kidney Injury and Construction of a Prediction Model

Purpose

The predictive value of the Systemic Immune-Inflammation Index (SII) on mortality in patients with sepsis-associated acute kidney injury (S-AKI) remains unclear. This study aims to investigate the predictive value of SII levels at the Intensive Care Unit (ICU) on the 28-day mortality of S-AKI patients.

Patients and Methods

S-AKI patients admitted to the ICU of Henan Provincial People's Hospital from January 1, 2023, to December 31, 2023. Patients who were diagnosed with S-AKI were divided into survival and death groups based on their 28-day outcome after ICU admission. Using receiver operating characteristic (ROC) curves to determine the best cut-off values and prognostic abilities of various parameters. Kaplan-Meier survival curves describe the 28-day survival of patients after ICU admission. Cox regression analysis identified the main risk factors associated with mortality in S-AKI patients, constructing a predictive nomogram. The concordance index (C-index) and decision curve analysis were used to validate the predictive ability of this model.

Results

A total of 216 patients with S-AKI were included. ROC analysis showed that SII had the highest predictive value for mortality risk in S-AKI patients after ICU admission. Compared with the low-SII group, the high-SII group had higher 28-day (86.7% vs 32.4%, respectively, P <0.001) mortality rate. Based on Cox regression analysis, a nomogram predictive model was constructed, including age, respiratory failure, SII levels, number of organ dysfunctions at ICU admission, sequential organ failure assessment (SOFA), and acute physiology and chronic health evaluation II (APACHEII). The C-index for predicting the 28-day survival rate was 0.682. Decision curve analysis indicated a high level of clinical predictive efficacy.

Conclusion

SII serves as a potential biomarker for predicting the prognosis of S-AKI patients. The constructed nomogram prognostic model can aid in assessing the prognosis of S-AKI patients.

Role of mesenchymal stem cells in sepsis and their therapeutic potential in sepsis‑associated myopathy (Review)

Sepsis‑induced myopathy (SIM) is one of the leading causes of death in critically ill patients. SIM mainly involves the respiratory and skeletal muscles of patients, resulting in an increased risk of lung infection, aggravated respiratory failure, and prolonged mechanical ventilation and hospital stay. SIM is also an independent risk factor associated with increased mortality in critically ill patients. At present, no effective treatment for SIM has yet been established. However, mesenchymal stem cells (MSCs) have emerged as a promising therapeutic approach and have been utilized in the treatment of various clinical conditions. A significant body of basic and clinical research supports the efficacy of MSCs in managing sepsis and muscle‑related diseases. This literature review aims to explore the relationship between MSCs and sepsis, as well as their impact on skeletal muscle‑associated diseases. Additionally, the present review discusses the potential mechanisms and therapeutic benefits of MSCs in the context of SIM.

Upregulation of Cullin1 neddylation promotes glycolysis and M1 polarization of macrophage via NF-κB p65 pathway in sepsis

This study aimed to explore the underlying mechanism of neddylation in macrophage polarization during sepsis. A mouse model of sepsis was established by cecal ligation and puncture (CLP). ELISA and Flow cytometry were performed to analyze the generation of pro-inflammatory factors and M1/M2 macrophage polarization, respectively. Western blotting was applied to detect NEDD8-mediated neddylation and glycolysis-related proteins. ECAR method was used to analyze the glycolysis level. HE staining was applied to detect the lung injury. The bacterial load in peritoneal cavity and peripheral blood was determined by counting the colony-forming units. The results showed the upregulated neddylation, M1 polarization and glycolysis of macrophage in patients with sepsis and CLP-challenged mice. NEDD8-mediated Cullin1 neddylation promoted M1 polarization and glycolysis to accelerate inflammation via NF-κB p65 pathway in E.coli-treated Raw264.7 cells. MLN4924 treatment alleviated sepsis by inhibiting neddylation to prevent M1 polarization in CLP-challenged mice. In summary, this study demonstrated that upregulation of NEDD8-mediated Cullin1 neddylation promotes glycolysis and M1 polarization of macrophage via NF-κB p65 pathway, accelerating inflammation in sepsis.

Application of targeted drug delivery by cell membrane-based biomimetic nanoparticles for inflammatory diseases and cancers

Drug-carrying nanoparticles can be recognized and captured by macrophages and cleared away by the immune system, resulting in reduced drug efficacy and representing the main drawbacks. Biomimetic nanoparticles, which are coated with cell membranes from natural resources, have been applied to address this problem. This type of nanoparticle maintains some specific biological activities, allowing them to carry drugs reaching designated tissues effectively and have a longer time in circulation. This review article aims to summarize recent progress on biomimetic nanoparticles based on cell membranes. In this paper, we have introduced the classification of biomimetic nanoparticles, their preparation and characterization, and their applications in inflammatory diseases and malignant tumors. We have also analyzed the shortcomings and prospects of this technology, hoping to provide some clues for basic researchers and clinicians engaged in this field.

Personalized, disease-stage specific, rapid identification of immunosuppression in sepsis

Introduction

Data overlapping of different biological conditions prevents personalized medical decision-making. For example, when the neutrophil percentages of surviving septic patients overlap with those of non-survivors, no individualized assessment is possible. To ameliorate this problem, an immunological method was explored in the context of sepsis.

Methods

Blood leukocyte counts and relative percentages as well as the serum concentration of several proteins were investigated with 4072 longitudinal samples collected from 331 hospitalized patients classified as septic (n=286), non-septic (n=43), or not assigned (n=2). Two methodological approaches were evaluated: (i) a reductionist alternative, which analyzed variables in isolation; and (ii) a non-reductionist version, which examined interactions among six (leukocyte-, bacterial-, temporal-, personalized-, population-, and outcome-related) dimensions.

Results

The reductionist approach did not distinguish outcomes: the leukocyte and serum protein data of survivors and non-survivors overlapped. In contrast, the non-reductionist alternative differentiated several data groups, of which at least one was only composed of survivors (a finding observable since hospitalization day 1). Hence, the non-reductionist approach promoted personalized medical practices: every patient classified within a subset associated with 100% survival subset was likely to survive. The non-reductionist method also revealed five inflammatory or disease-related stages (provisionally named 'early inflammation, early immunocompetence, intermediary immuno-suppression, late immuno-suppression, or other'). Mortality data validated these labels: both 'suppression' subsets revealed 100% mortality, the 'immunocompetence' group exhibited 100% survival, while the remaining sets reported two-digit mortality percentages. While the 'intermediary' suppression expressed an impaired monocyte-related function, the 'late' suppression displayed renal-related dysfunctions, as indicated by high concentrations of urea and creatinine.

Discussion

The data-driven differentiation of five data groups may foster early and non-overlapping biomedical decision-making, both upon admission and throughout their hospitalization. This approach could evaluate therapies, at personalized level, earlier. To ascertain repeatability and investigate the dynamics of the 'other' group, additional studies are recommended.

Multi-omics analysis reveals the interplay between pulmonary microbiome and host in immunocompromised patients with sepsis-induced acute lung injury

The mechanisms behind the high inflammatory state and immunocompromise in severe sepsis remain unclear. While microbiota's role in immune regulation is known, the impact of pulmonary microbiota on sepsis progression is not fully understood. This study aims to investigate pulmonary microbial characteristics in septic patients and their relationship with host immune-related genes and clinical features. Fifty-four sepsis patients were divided into the immunocompromised host (ICH) group (n = 18) and the control group (n = 36). Bronchoalveolar lavage fluid (BALF) was analyzed using metagenomic next-generation sequencing (mNGS) to assess the pulmonary microbiome, and transcriptomic sequencing evaluated host gene expression. The pulmonary microbiota network in the ICH group showed notable alterations. Symbiotic bacteria like Streptococcus salivarius and Streptococcus oralis were key taxa in the control group. In contrast, opportunistic pathogens such as Campylobacter concisus and Prevotella melaninogenica, typically linked to infections in various body sites, dominated in the ICH group. Transcriptomic analysis revealed differential genes between the two groups. The downregulated differential genes in the ICH group were primarily enriched in pathways related to T-cell activation and the Type I interferon signaling pathway, both crucial for the immune system. Further correlation analysis identified significant associations between certain microbes and host genes, as well as clinical indicators, particularly with species like Campylobacter concisus, Streptococcus salivarius, Streptococcus oralis, and several species of Veillonella. These findings suggest that alterations in the pulmonary microbiome, especially the presence of opportunistic pathogens, may contribute to immune dysregulation in immunocompromised septic patients, warranting further research to explore causal relationships.

IMPORTANCE

Recent research has substantiated the significant role of microbiota in immune regulation, which could influence high inflammatory state and immunocompromise in patients with severe sepsis, as well as provide new opportunities for acute lung injury induced by sepsis diagnosis and treatment. Our study identified some potential critical microbes (Campylobacter concisus and several species of Veillonella), which were correlated with immune-related genes and might be the novel target to regulate immunotherapy in sepsis.

Nanotechnology-Based Drug Delivery Systems for Treating Acute Kidney Injury

Acute kidney injury (AKI) is a disease that is characterized by a rapid decline in renal function and has a relatively high incidence in hospitalized patients. Sepsis, renal hypoperfusion, and nephrotoxic drug exposure are the main causes of AKI. The major therapy measures currently include supportive treatment, symptomatic treatment, and kidney transplantation. These methods are supportive treatments, and their results are not satisfactory. Fortunately, many new treatments that markedly improve the AKI therapy efficiency are emerging. These include antioxidant therapy, ferroptosis therapy, anti-inflammatory therapy, autophagy therapy, and antiapoptotic therapy. In addition, the development of nanotechnology has further promoted therapeutic effects on AKI. In this review, we highlight recent advances in the development of nanocarriers for AKI drug delivery. Emphasis has been placed on the latest developments in nanocarrier modification and design. We also summarize the applications of different nanocarriers in AKI treatment. Finally, the advantages and challenges of nanocarrier applications in AKI are summarized, and several nanomedicines that have been approved for clinical trials to treat diverse kidney diseases are listed.

Multiomics Analysis Identifies Prognostic Signatures for Sepsis-Associated Hepatocellular Carcinoma in Emergency Medicine

Objectives

Sepsis, caused by the body's response to infection, poses a life-threatening condition and represents a significant global health challenge. Characterized by dysregulated immune response to infection, sepsis may lead to organ dysfunction and failure, ultimately resulting in high mortality rates. The liver plays a crucial role in sepsis, yet the role of differentially expressed genes in septic patients remains unclear in hepatocellular carcinoma (HCC). In this study, we aim to investigate the significance of differentially expressed genes related to sepsis in the occurrence and prognosis of tumors in HCC.

Methods

We conducted analyses by obtaining gene transcriptome data and clinical data of HCC cases from The Cancer Genome Atlas (TCGA). Furthermore, we obtained transcriptomic sequencing results of septic patients from the Gene Expression Omnibus (GEO) database, identified intersecting differentially expressed genes between the two, and performed survival analysis on the samples using LASSO and Cox regression analysis. Combining analyses of tumor mutation burden (TMB) and immune function, we further elucidated the mechanisms of sepsis-related genes in the prognosis and treatment of HCC.

Results

We established a prognostic model consisting of four sepsis-related genes: KRT20, PAEP, CCR3, and ANLN. Both the training and validation sets showed excellent outcomes in the prognosis of tumor patients, with significantly longer survival times observed in the low-risk group based on this model compared to the high-risk group. Furthermore, analyses, such as differential analysis of tumor mutation burden, immune function analysis, GO/KEGG pathway enrichment analysis, and drug sensitivity analysis, also demonstrated the potential mechanisms of action of sepsis-related genes.

Conclusions

Models constructed based on sepsis-related genes have shown excellent predictive ability in prognosis and differential analysis of drug sensitivity among tumor patients. These predictive models can enhance patient prognosis and inform the creation of early treatment protocols for sepsis, consequently aiding in the prevention of sepsis-induced HCC development through the modulation of the overall immune status. This may play a crucial role in patient management and immunotherapy, providing valuable reference for subsequent research.

Factors affecting neutrophil functions during sepsis: human microbiome and epigenetics

Sepsis is a severe disease that occurs when the body's immune system reacts excessively to infection. The body's response, which includes an intense antibacterial reaction, can damage its tissues and organs. Neutrophils are the major components of white blood cells in circulation, play a vital role in innate immunity while fighting against infections, and are considered a feature determining sepsis classification. There is a plethora of basic research detailing neutrophil functioning, among which, the study of neutrophil extracellular traps is providing novel insights into mechanisms and treatments of sepsis. This review explores their functions, dysfunctions, and influences in the context of sepsis. The interplay between neutrophils and the human microbiome and the impact of DNA methylation on neutrophil function in sepsis are crucial areas of study. The interaction between neutrophils and the human microbiome is complex, particularly in the context of sepsis, where dysbiosis may occur. We highlight the importance of deciphering neutrophils' functional alterations and their epigenetic features in sepsis because it is critical for defining sepsis endotypes and opening up the possibility for novel diagnostic methods and therapy. Specifically, epigenetic signatures are pivotal since they will provide a novel implication for a sepsis diagnostic method when used in combination with the cell-free DNA. Research is exploring how specific patterns of DNA methylation in neutrophils, detectable in cell-free DNA, could serve as biomarkers for the early detection of sepsis.

A New Strategy for Targeting UCP2 to Modulate Glycolytic Reprogramming as a Treatment for Sepsis A New Strategy for Targeting UCP2

Sepsis is a severe and life-threatening disease caused by infection, characterized by a dysregulated immune response. Unfortunately, effective treatment strategies for sepsis are still lacking. The intricate interplay between metabolism and the immune system limits the treatment options for sepsis. During sepsis, there is a profound shift in cellular energy metabolism, which triggers a metabolic reprogramming of immune cells. This metabolic alteration impairs immune responses, giving rise to excessive inflammation and immune suppression. Recent research has demonstrated that UCP2 not only serves as a critical target in sepsis but also functions as a key metabolic switch involved in immune cell-mediated inflammatory responses. However, the regulatory mechanisms underlying this modulation are complex. This article focuses on UCP2 as a target and discusses metabolic reprogramming during sepsis and the complex regulatory mechanisms between different stages of inflammation. Our research indicates that overexpression of UCP2 reduces the Warburg effect, restores mitochondrial function, and improves the prognosis of sepsis. This discovery aims to provide a promising approach to address the significant challenges associated with metabolic dysfunction and immune paralysis.

Classification and functional analysis of disulfidptosis-associated genes in sepsis

Sepsis represents a critical condition characterized by multiple-organ dysfunction resulting from inflammatory response to infection. Disulfidptosis is a newly identified type of programmed cell death that is intimately associated with the actin cytoskeleton collapse caused by glucose starvation and disulfide stress, but its role in sepsis is largely unknown. The study was to adopt a diagnostic and prognostic signature for sepsis with disulfidptosis based on the differentially expressed genes (DEGs) between sepsis and healthy people from GEO database. The disulfidptosis hub genes associated with sepsis were identified, and then developed consensus clustering and immune infiltration characteristics. Next, we evaluated disulfidptosis-related risk genes by using LASSO and Random Forest algorithms, and constructed the diagnostic sepsis model by nomogram. Finally, immune infiltration, GSVA analysis and mRNA-miRNA networks based on disulfidptosis-related DEGs were screened. There are five upregulated disulfidptosis-related genes and seven downregulated genes were filtered out. The six intersection disulfidptosis-related genes including LRPPRC, SLC7A11, GLUT, MYH9, NUBPL and GYS1 exhibited higher predictive ability for sepsis with an accuracy of 99.7%. In addition, the expression patterns of the critical genes were validated. The study provided a comprehensive view of disulfidptosis-based signatures to predict the prognosis, biological features and potential treatment directions for sepsis.

Identification of Immune-Related Genes as Potential Biomarkers in Early Septic Shock

INTRODUCTION

Septic shock, a severe manifestation of infection-induced systemic immune response, poses a critical threat resulting in life-threatening multi-organ failure. Early diagnosis and intervention are imperative due to the potential for irreversible organ damage. However, specific and sensitive detection tools for the diagnosis of septic shock are still lacking.

METHODS

Gene expression files of early septic shock were obtained from the Gene Expression Omnibus (GEO) database. CIBERSORT analysis was used to evaluate immune cell infiltration. Genes related to immunity and disease progression were identified using weighted gene co-expression network analysis (WGCNA), followed by enrichment analysis. CytoHubba was then employed to identify hub genes, and their relationships with immune cells were explored through correlation analysis. Blood samples from healthy controls and patients with early septic shock were collected to validate the expression of hub genes, and an external dataset was used to validate their diagnostic efficacy.

RESULTS

Twelve immune cells showed significant infiltration differences in early septic shock compared to control, such as neutrophils, M0 macrophages, and natural killer cells. The identified immune and disease-related genes were mainly enriched in immune, cell signaling, and metabolism pathways. In addition, six hub genes were identified (PECAM1, F11R, ITGAL, ICAM3, HK3, and MCEMP1), all significantly associated with M0 macrophages and exhibiting an area under curve of over 0.7. These genes exhibited abnormal expression in patients with early septic shock. External datasets and real-time qPCR validation supported the robustness of these findings.

CONCLUSION

Six immune-related hub genes may be potential biomarkers for early septic shock.

The role of lipoprotein‑associated phospholipase A2 in inflammatory response and macrophage infiltration in sepsis and the regulatory mechanisms

Lipoproteinassociated phospholipase A2 (Lp-PLA2), encoded by the phospholipase A2 group VII (Pla2g7) gene, has been pertinent to inflammatory responses. This study investigates the correlation between Lp-PLA2 and inflammatory injury in septic mice and explores its regulatory mechanism. Lp-PLA2 was found to be upregulated in the serum of septic mice induced by cecal ligation and puncture and in the culture supernatant of RAW264.7 cells following lipopolysaccharide and adenosine triphosphate treatments. The contents of Lp-PLA2 were positively correlated with increased concentrations of proinflammatory cytokines in patients with sepsis. Both animal and cellular models showed increased concentrations of proinflammatory cytokines. Spi-1 proto-oncogene (Spi1), highly expressed in these models, was found to activate Pla2g7 transcription. Knockdown of Pla2g7 or Spi1 reduced the proinflammatory cytokine production, mitigated organ damage in mice, and suppressed macrophage migration in vitro. Retinoblastoma binding protein 6 (Rbbp6), poorly expressed in both models, was found to reduce Spi1 protein stability through ubiquitination modification. Rbbp6 overexpression similarly suppressed inflammatory activation of RAW264.7 cells, which was counteracted by Pla2g7 or Spi1 upregulation. In summary, this study demonstrates that the Pla2g7 loss and Spi1 upregulation participate in inflammatory responses in sepsis by elevating the Lp-PLA2 levels.

Progress in the study of the correlation between sepsis and intestinal microecology

Sepsis, a disease with high incidence, mortality, and treatment costs, has a complex interaction with the gut microbiota. With advances in high-throughput sequencing technology, the relationship between sepsis and intestinal dysbiosis has become a new research focus. However, owing to the intricate interplay between critical illness and clinical interventions, it is challenging to establish a causal relationship between sepsis and intestinal microbiota imbalance. In this review, the correlation between intestinal microecology and sepsis was summarized, and new therapies for sepsis intervention based on microecological target therapy were proposed, and the shortcomings of bacterial selection and application timing in clinical practice were addressed. In conclusion, current studies on metabolomics, genomics and other aspects aimed at continuously discovering potential probiotics are all providing theoretical basis for restoring intestinal flora homeostasis for subsequent treatment of sepsis.

Lymphopenia in sepsis: a narrative review

This narrative review provides an overview of the evolving significance of lymphopenia in sepsis, emphasizing its critical function in this complex and heterogeneous disease. We describe the causal relationship of lymphopenia with clinical outcomes, sustained immunosuppression, and its correlation with sepsis prediction markers and therapeutic targets. The primary mechanisms of septic lymphopenia are highlighted. In addition, the paper summarizes various attempts to treat lymphopenia and highlights the practical significance of promoting lymphocyte proliferation as the next research direction.

Cronobacter sakazakii induced sepsis-associated arrhythmias through its outer membrane vesicles

Sepsis-induced arrhythmia, linked to sudden cardiac death, is associated with gut microbiota, though the exact relationship is unclear. This study aimed to elucidate the relationship between Cronobacter sakazakii (C. sakazakii) and arrhythmia. The relative abundance of C. sakazakii was increased in cecal ligation and puncture (CLP)-induced septic mice. Live C. sakazakii, supernatant, and outer membrane vesicles (OMVs) resulted in premature ventricular beat (PVB), sinus arrhythmia (SA), and increased arrhythmia and mortality in sepsis model through dysregulated ion channel proteins. Moreover, short-chain fatty acids (SCFAs) showed antibacterial effects in vitro. We confirmed sodium acetate (C2) and sodium butyrate (C4) protect from C. sakazakii-induced arrhythmia, and C2 and C4 protected from septic arrhythmia by activating free fatty acid receptor 2 and 3 (FFAR2 and FFAR3) in mice. These findings point to how C. sakazakii's OMVs trigger arrhythmia, and SCFAs may be a treatment for septic arrhythmia.

Lactate's impact on immune cells in sepsis: unraveling the complex interplay

Lactate significantly impacts immune cell function in sepsis and septic shock, transcending its traditional view as just a metabolic byproduct. This review summarizes the role of lactate as a biomarker and its influence on immune cell dynamics, emphasizing its critical role in modulating immune responses during sepsis. Mechanistically, key lactate transporters like MCT1, MCT4, and the receptor GPR81 are crucial in mediating these effects. HIF-1α also plays a significant role in lactate-driven immune modulation. Additionally, lactate affects immune cell function through post-translational modifications such as lactylation, acetylation, and phosphorylation, which alter enzyme activities and protein functions. These interactions between lactate and immune cells are central to understanding sepsis-associated immune dysregulation, offering insights that can guide future research and improve therapeutic strategies to enhance patient outcomes.

Early B lymphocyte subsets in blood predict prognosis in sepsis

Background

B lymphocytes play a key role in immunosuppression. This study investigated the prognostic value of B cell subsets in sepsis.

Methods

Flow cytometry was used to assess peripheral B cell subsets from patients with sepsis on the first and seventh days following admission, as well as 111 healthy controls. The patients were divided into survivors and non-survivors, based on 28-day prognosis.

Results

The analysis showed abnormal distribution and selective depletion of B cells and its subsets in the early stages of sepsis. On day 1, compared with survivors, non-survivors showed significant decreases in the proportion and absolute count of transitional (Tr) B cells, reductions in the proportion of CD5+ B cells, and increases in the proportion of double-negative (DN) B cells. On day 7, the proportions and absolute counts of Tr and CD5+ B cells significantly decreased whereas the proportion of DN B cells significantly increased in non-survivors. Ninety-four survivors and 15 non-survivors were included in our paired-sample rank-sum test. Compared to day 1, only the survivors showed significant increases in absolute B, Tr B, and CD5+ B cell counts by day 7. Multivariate Cox regression analysis showed that the proportion of DN B cells on day 1 (hazard ratio = 1.092 [95% confidence interval: 1.035-1.152], P = 0.001) was a risk factor for mortality, and Kaplan-Meier survival curve analysis showed that patients with proportions of DN B cells > 11.81% on day 1 had poorer prognoses. Receiver operating characteristic curve analysis showed that B cell subset parameters could predict mortality (area under the receiver operating characteristic curve [AUC], 0.741) and enhanced the prognostic value of the Acute Physiology and Chronic Health Evaluation II score (AUC, 0.840).

Conclusion

Our study revealed that deficiencies of B, Tr B, and CD5+ B cells, as well as a persistent increase in the proportion of DN B cells, were associated with poor prognosis-and that B cell subsets showed predictive value to mortality. These results provide new insights into the roles of B cell subsets in sepsis, as well as ways to better manage its progression and predict its course.

Investigating immune dysregulation and hub genes in septic cardiomyopathy development

Septic cardiomyopathy is a life-threatening heart dysfunction caused by severe infection. Considering the complexity of pathogenesis and high mortality, the identification of efficient biomarkers are needed to guide clinical practice. Based on multimicroarray analysis, this study aimed to explore the pathogenesis of septic cardiomyopathy and the related immune landscape. The results showed that septic cardiomyopathy resulted in organ dysfunction due to extreme pro- and anti-inflammatory effects. In this process, KLRG1, PRF1, BCL6, GAB2, MMP9, IL1R1, JAK3, IL6ST, and SERPINE1 were identified as the hub genes regulating the immune landscape of septic cardiomyopathy. Nine transcription factors regulated the expression of these genes: SRF, STAT1, SP1, RELA, PPARG, NFKB1, PPARA, SMAD3, and STAT3. The hub genes activated the Th17 cell differentiation pathway, JAK-STAT signaling pathway, and cytokine‒cytokine receptor interaction pathway. These pathways were mainly involved in regulating the inflammatory response, adaptive immune response, leukocyte-mediated immunity, cytokine-mediated immunity, immune effector processes, myeloid cell differentiation, and T-helper cell differentiation. These nine hub genes could be considered biomarkers for the early prediction of septic cardiomyopathy.

Suppression of overactivated immunity in the early stage is the key to improve the prognosis in severe burns

Background

Severe burns can lead to systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) due to inflammation-immunity dysregulation. This study aimed to identify key immune-related molecules and potential drugs for immune regulation in severe burn treatment.

Method

Microarray datasets GSE77791 and GSE37069 were analyzed to identify immune-related differentially expressed genes (DEGs), enriched pathways and prognosis-related genes. The DGIdb database was used to identify potentially clinically relevant small molecular drugs for hub DEGs. Hub DEGs were validated by total RNA from clinical blood samples through qPCR. The efficacy of drug candidates was tested in a severe burn mouse model. Pathologic staining was used to observe organ damage. Enzyme Linked Immunosorbent Assay (ELISA) was used to detect the serum IL-1b, IL-6, TNF-a and MCP-1 contents. Activation of the NF-κB inflammatory pathway was detected by western blotting. Transcriptome sequencing was used to observe inflammatory-immune responses in the lung.

Results

A total of 113 immune-related DEGs were identified, and the presence of immune overactivation was confirmed in severe burns. S100A8 was not only significantly upregulated and identified to be prognosis-related among the hub DEGs but also exhibited an increasing trend in clinical blood samples. Methotrexate, which targets S100A8, as predicted by the DGIdb, significantly reduces transcription level of S100A8 and inflammatory cytokine content in blood, organ damage (lungs, liver, spleen, and kidneys) and mortality in severely burned mice when combined with fluid resuscitation. The inflammatory-immune response was suppressed in the lungs.

Conclusion

S100A8 with high transcription level in blood is a potential biomarker for poor severe burn prognosis. It suggested that methotrexate has a potential application in severe burn immunotherapy. Besides, it should be emphasized that fluid resuscitation is necessary for the function of methotrexate.

Innate immune response in acute critical illness: a narrative review

BACKGROUND

Activation of innate immunity is a first line of host defense during acute critical illness (ACI) that aims to contain injury and avoid tissue damages. Aberrant activation of innate immunity may also participate in the occurrence of organ failures during critical illness. This review aims to provide a narrative overview of recent advances in the field of innate immunity in critical illness, and to consider future potential therapeutic strategies.

MAIN TEXT

Understanding the underlying biological concepts supporting therapeutic strategies modulating immune response is essential in decision-making. We will develop the multiple facets of innate immune response, especially its cellular aspects, and its interaction with other defense mechanisms. We will first describe the pathophysiological mechanisms of initiation of innate immune response and its implication during ACI. We will then develop the amplification of innate immunity mediated by multiple effectors. Our review will mainly focus on myeloid and lymphoid cellular effectors, the major actors involved in innate immune-mediated organ failure. We will third discuss the interaction and integration of innate immune response in a global view of host defense, thus considering interaction with non-immune cells through immunothrombosis, immunometabolism and long-term reprogramming via trained immunity. The last part of this review will focus on the specificities of the immune response in children and the older population.

CONCLUSIONS

Recent understanding of the innate immune response integrates immunity in a highly dynamic global vision of host response. A better knowledge of the implicated mechanisms and their tissue-compartmentalization allows to characterize the individual immune profile, and one day eventually, to develop individualized bench-to-bedside immunomodulation approaches as an adjuvant resuscitation strategy.

Exposome-Wide Ranking to Uncover Environmental Chemicals Associated with Dyslipidemia: A Panel Study in Healthy Older Chinese Adults from the BAPE Study

BACKGROUND

Environmental contaminants (ECs) are increasingly recognized as crucial drivers of dyslipidemia and cardiovascular disease (CVD), but the comprehensive impact spectrum and interlinking mechanisms remain uncertain.

OBJECTIVES

We aimed to systematically evaluate the association between exposure to 80 ECs across seven divergent categories and markers of dyslipidemia and investigate their underpinning biomolecular mechanisms via an unbiased integrative approach of internal chemical exposome and multi-omics.

METHODS

A longitudinal study involving 76 healthy older adults was conducted in Jinan, China, and participants were followed five times from 10 September 2018 to 19 January 2019 in 1-month intervals. A broad spectrum of seven chemical categories covering the prototypes and metabolites of 102 ECs in serum or urine as well as six serum dyslipidemia markers [total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein (Apo)A1, ApoB, and ApoE4] were measured. Multi-omics, including the blood transcriptome, serum/urine metabolome, and serum lipidome, were profiled concurrently. Exposome-wide association study and the deletion/substitution/addition algorithms were applied to explore the associations between 80 EC exposures detection frequency > 50 % and dyslipidemia markers. Weighted quantile sum regression was used to assess the mixture effects and relative contributions. Multi-omics profiling, causal inference model, and pathway analysis were conducted to interpret the mediating biomolecules and underlying mechanisms. Examination of cytokines and electrocardiograms was further conducted to validate the observed associations and biomolecular pathways.

RESULTS

Eight main ECs [1-naphthalene, 1-pyrene, 2-fluorene, dibutyl phosphate, tri-phenyl phosphate, mono-(2-ethyl-5-hydroxyhexyl) phthalate, chromium, and vanadium] were significantly associated with most dyslipidemia markers. Multi-omics indicated that the associations were mediated by endogenous biomolecules and pathways, primarily pertinent to CVD, inflammation, and metabolism. Clinical measures of cytokines and electrocardiograms further cross-validated the association of these exogenous ECs with systemic inflammation and cardiac function, demonstrating their potential mechanisms in driving dyslipidemia pathogenesis.

DISCUSSION

It is imperative to prioritize mitigating exposure to these ECs in the primary prevention and control of the dyslipidemia epidemic. https://doi.org/10.1289/EHP13864.

Exploring the potential mechanisms of Rehmannia glutinosa in treating sepsis based on network pharmacology

The present study utilized network pharmacology to identify therapeutic targets and mechanisms of Rehmannia glutinosa in sepsis treatment. RNA-sequencing was conducted on peripheral blood samples collected from 23 sepsis patients and 10 healthy individuals. Subsequently, the RNA sequence data were analyzed for differential expression. Identification of active components and their putative targets was achieved through the HERB and SwissTarget Prediction databases, respectively. Functional enrichment analysis was performed using GO and KEGG pathways. Additionally, protein-protein interaction networks were constructed and survival analysis of key targets was conducted. Single-cell RNA sequencing provided cellular localization data, while molecular docking explored interactions with central targets. Results indicated significant involvement of identified targets in inflammation and Th17 cell differentiation. Survival analysis linked several targets with mortality rates, while molecular docking highlighted potential interactions between active components and specific targets, such as rehmaionoside a with ADAM17 and rehmapicrogenin with CD81. Molecular dynamics simulations confirmed the stability of these interactions, suggesting Rehmannia glutinosa's role in modulating immune functions in sepsis.

Molecular mechanisms of Sepsis attacking the immune system and solid organs

Remarkable progress has been achieved in sepsis treatment in recent times, the mortality rate of sepsis has experienced a gradual decline as a result of the prompt administration of antibiotics, fluid resuscitation, and the implementation of various therapies aimed at supporting multiple organ functions. However, there is still significant mortality and room for improvement. The mortality rate for septic patients, 22.5%, is still unacceptably high, accounting for 19.7% of all global deaths. Therefore, it is crucial to thoroughly comprehend the pathogenesis of sepsis in order to enhance clinical diagnosis and treatment methods. Here, we summarized classic mechanisms of sepsis progression, activation of signal pathways, mitochondrial quality control, imbalance of pro-and anti- inflammation response, diseminated intravascular coagulation (DIC), cell death, presented the latest research findings for each mechanism and identify potential therapeutic targets within each mechanism.

U-shaped correlation of lymphocyte count with all-cause hospital mortality in sepsis and septic shock patients: a MIMIC-IV and eICU-CRD database study

BACKGROUND

In sepsis, the relationship between lymphocyte counts and patient outcomes is complex. Lymphocytopenia and lymphocytosis significantly influence survival, illustrating the dual functionality of lymphocytes in responding to infections. This study investigates this complex interaction, focusing on how variations in lymphocyte counts correlate with all-cause hospital mortality among sepsis patients.

METHODS

This retrospective cohort study analyzed data from two extensive critical care databases: the Medical Information Mart for Intensive Care IV 2.0 (MIMIC-IV 2.0) from Beth Israel Deaconess Medical Center, Boston, Massachusetts, and the eICU Collaborative Research Database (eICU-CRD), which was Multi-center database from over 200 hospitals across the United States conducted by Philips eICU Research Institute. We included adult patients aged 18 years and older who met the Sepsis-3 criteria, characterized by documented or suspected infection and a Sequential Organ Failure Assessment (SOFA) score of 2 or higher. Sepsis patients were categorized into quartiles based on lymphocyte counts. The primary outcome was all-cause mortality in the hospital, with 90 and 60-day all-cause mortality as the secondary outcomes. Univariable and multivariable Cox proportional hazard regressions were utilized to assess lymphocyte counts' impact on hospital mortality. An adjusted restricted cubic spline (RCS) analysis was performed to elucidate this relationship further. Subgroup analyses were also conducted to explore the association across various comorbidity groups among sepsis and septic shock patients.

RESULTS

Our study included 37,054 patients, with an observed in-hospital mortality rate of 16.6%. Univariable and multivariable Cox proportional hazard regression models showed that lymphocyte counts were independently associated with in-hospital mortality (HR = 1.04, P < 0.01; HR = 1.06, P < 0.01). RCS regression analysis revealed a U-shaped relationship between lymphocyte levels and hospital mortality risk in sepsis and septic shock patients (P for overall < 0.001, P for nonliner < 0.01; P for overall = 0.002, P for nonliner = 0.014). Subgroup analyses revealed that elevated lymphocyte counts correlated with increased hospital mortality among sepsis patients with liver disease and requiring renal replacement therapy (P for overall = 0.021, P for nonliner = 0.158; P for overall = 0.025, P for nonliner = 0.759). These findings suggest that lymphocytes may have enhanced prognostic value in specific subsets of critically ill sepsis patients.

CONCLUSION

Our findings demonstrate that lymphocyte counts are a significant independent predictor of hospital mortality in sepsis and septic shock patients. We observed a U-shaped association between lymphocyte levels and mortality risk, indicating that high and low counts are linked to increased mortality. This result highlights the complex role of lymphocytes in sepsis outcomes and suggests the need for further investigation into the underlying mechanisms and potential therapeutic approaches. Integrating lymphocyte count assessment into risk stratification algorithms and clinical decision support tools could enhance the early identification of high-risk sepsis patients.