Immunosuppression in sepsis: a novel understanding of the disorder and a new therapeutic approach

A DNA-based nanorobot for targeting, hitchhiking, and regulating neutrophils to enhance sepsis therapy

Targeted regulation of neutrophils is an effective approach for treating neutrophil-driven inflammatory diseases, but challenges remain in minimizing off-target effects and extending drug half-life. A DNA-based nanorobot was developed to target neutrophils by using an N-acetyl Pro-Gly-Pro (Ac-PGP) peptide to specifically bind to the C-X-C motif of chemokine receptor 2 (CXCR2) on neutrophil membranes. This robot (a tetrahedral framework nucleic acid modified with Ac-PGP, APT) identified and hitchhiked neutrophils to accumulate at inflammatory sites and prolong its half-lives, whilst also was internalized to influence the neutrophil cell cycle and maturation process to regulate oxidative stress, inflammation, migration, and recruitment in both in vivo and in vitro inflammation experiments. Consequently, the tissue damage caused by sepsis was greatly reduced. This novel neutrophil-based nanorobot highlights the high precision of targeting and regulating neutrophils, and presents a potential strategy for treating multiple neutrophil-driven diseases.

Enhanced resistance to Listeria infection in mice surviving sepsis: the role of lipid metabolism and myeloid cell reprogramming

Introduction

Immune resilience is the capacity of the immune system to recover from sepsis-induced organ injury and reestablish host defense. While sepsis survivors are often viewed as immunocompromised, recent studies suggest that some may acquire adaptive immune traits that enhance resistance to secondary infections.

Methods

We employed a murine cecal ligation and puncture (CLP) model to study polymicrobial sepsis and subsequent immune responses. Listeria monocytogenes was used as a model intracellular pathogen to assess immune protection. We analyzed myeloid cell phenotypes using single-cell RNA sequencing and evaluated lipid metabolic changes through quantitative RT-PCR, immunohistochemistry, serum cytokine assays, and plasma lipidomics.

Results

Sepsis-surviving mice showed enhanced resistance to Listeria infection. Single-cell RNA sequencing revealed transcriptional reprogramming in splenic CD11b+Ly6Chigh myeloid cells, including downregulation of lipoprotein lipase and lipid efflux genes. CD11b+ myeloid cells exhibited increased lipid droplet accumulation, accompanied by elevated serum interferon-gamma (IFN-γ) levels. Plasma lipidomics identified systemic lipid remodeling, with increased phosphatidylserine and decreased phosphatidylinositol and phosphatidylglycerol levels.

Discussion

Our findings suggest that sepsis survival induces lipid metabolic reprogramming in myeloid cells, contributing to enhanced immunity against intracellular pathogens. These insights reveal potential therapeutic targets within lipid metabolic pathways to improve host defense in sepsis survivors.

Glucagon-like peptide 1 level and risk of death within 90 days after intensive care unit admission: A substudy of the IVOIRE cohort

BACKGROUND

Elevated plasma levels of glucagon-like peptide-1 (GLP-1) have been associated with poor clinical outcome in patients with sepsis. This study investigated the association between GLP-1 levels, and survival at 90 days in a large cohort of critically ill patients.

METHODS

All patients aged ≥ 18 years admitted to the intensive care unit (ICU) in a large university hospital, and receiving ≥1 life support therapy for organ failure were eligible for inclusion. Plasma samples were taken within 24h of ICU admission. We measured GLP-1 using a commercial ELISA kit. Cumulative probability of death at 90 days (D90) was plotted using the Kaplan-Meier method by quartiles of GLP-1. The effect of GLP-1 quartile on D90 survival was analyzed using a Cox proportional hazards model.

RESULTS

A total of 507 patients had GLP-1 dosage; mean age 64.5 ± 14.5 years; 179 (35.3%) women. GLP-1 levels ranged from 0.03 to 129.2 (median 7.3[IQR:3.3;19.1]). Higher mean age, SOFA, SAPS II, and LPS 3HM were found in patients with higher GLP-1 quartile by univariate analysis. Overall, 229 patients (45.2%) died within 90 days. The cumulative probability of death was significantly associated with GLP-1 quartile (p log rank<0.0001). After adjustment for age, SOFA, renal replacement therapy and vasopressor treatment, a significantly increased risk was observed only for patients with the highest quartile of GLP-1 (adjusted hazard ratio 1.65 [1.06; 2.56] for 4th vs 1st quartile of GLP-1).

CONCLUSION

After adjusting for demographic and clinical characteristics, only the highest quartile of GLP-1 remained independently associated with an increased risk of death at 90 days after admission to ICU.

Advanced lung cancer inflammation index and short-term mortality in sepsis: a retrospective analysis

Background

Sepsis is a notable cause of death and poor prognosis in the intensive care unit (ICU). Presents an ambiguous association between advanced lung cancer inflammation (ALI) and short-term lethality in sepsis patients. The purpose of this study is to explore this relationship.

Methods

This retrospective study identified sepsis cases from the MIMIC-IV 3.0 dataset. Multivariable Cox regression analysis was used to evaluate the relationship between ALI and the risks of 30-day all-cause mortality (ACM) and ICU mortality. Kaplan-Meier (K-M) curves and log-rank tests were employed for survival analysis. Restricted cubic spline (RCS) regression was employed to explore the nonlinear association between ALI and mortality risk. Subgroup and sensitivity analyses were performed to confirm the reliability of the results and to evaluate the incremental effect of ALI on the prediction of short-term mortality.

Results

A total of 4,147 sepsis cases were included in this study, with a 30-day ACM rate of 26.7% and a 30-day ICU mortality rate of 18.5%. In the completely adjusted Cox model, patients in the highest quartile of log2-ALI had a 38% lower risk of 30-day ACM (HR = 0.62, p < 0.001) and a 29% lower risk of 30-day ICU mortality (HR = 0.71, p = 0.002) compared to those in the lowest quartile. K-M curves showed that the group with the lowest log2-ALI had the lowest 30-day ACM and ICU survival rates (log-rank p < 0.001). RCS showed a nonlinear relationship between log2-ALI and 30-day ACM (P-overall < 0.001, P-nonlinear < 0.05). In all subgroups, the relationship between log2-ALI and outcomes showed no notable heterogeneity (P for interaction > 0.05), and four different sensitivity analyses yielded robust results. The combination of sequential organ failure assessment (SOFA) score and log2-ALI improved the predictive ability for 30-day ACM, with significant increases in C-statistic, Net Reclassification Improvement (NRI), and Integrated Discrimination Improvement (IDI).

Conclusion

This research found that lower levels of ALI were notably linked to higher 30-day ACM and 30-day ICU mortality in sepsis patients, warranting further verification through prospective studies.

Exploring the Potential Role of the Cholinergic Anti-Inflammatory Pathway from the Perspective of Sepsis Pathophysiology

Sepsis is one of the most prevalent conditions in critical care medicine and is characterized by a high incidence, mortality, and poor prognosis, with no specific treatment currently available. The pathogenesis of sepsis is complex with a dysregulated inflammatory response at its core. If the initial inflammatory response is not promptly controlled, patients often develop multiple organ dysfunction syndrome or die, whereas survivors may experience post-sepsis syndrome. Regulation by the central and autonomic nervous systems is essential for maintaining inflammatory homeostasis. Among these, the cholinergic anti-inflammatory pathway (CAP) has been extensively studied in sepsis owing to its significant role in modulating inflammatory responses. Recent advancements in CAP-related interventions include minimally invasive vagus nerve stimulation, novel α7nAchR-targeting drugs, serum choline acetyltransferase and cholinesterase, acupuncture, and focused ultrasound stimulation therapy. This review primarily discusses the advantages, limitations, and therapeutic prospects of these approaches. Additionally, heart rate variability, which reflects changes in autonomic nervous system function, can serve as an indicator for assessing the functional status of the vagus nerve. In summary, modulation of inflammatory responses through the vagus nerve-mediated CAP represents a potential strategy for achieving precision medicine for sepsis. Future research should focus on conducting high-quality clinical studies on CAP-based therapies in the context of sepsis-induced inflammatory dysregulation. Incorporating indicators to evaluate the autonomic nervous system function may further elucidate the impact of inflammatory dysregulation in the body.

SAMSN1 causes sepsis immunosuppression by inducing macrophages to express coinhibitory molecules that cause T-cell exhaustion via KEAP1-NRF2 signaling

BACKGROUND

Immunosuppression is closely related to the pathogenesis of sepsis, but the underlying mechanisms have not yet been fully elucidated. In this study, we aimed to examine the role of the Sterile Alpha Motif, Src Homology 3 domain and nuclear localization signal 1 (SAMSN1) in sepsis and elucidate its potential molecular mechanism in sepsis induced immunosuppression.

METHODS

RNA sequencing databases were used to validate SAMSN1 expression in sepsis. The impact of SAMSN1 on sepsis was verified using gene knockout mice. Flow cytometry was employed to delineate how SAMSN1 affects immunity in sepsis, focusing on immune cell types and T cell functions. Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated gene editing in RAW264.7 macrophages enabled interrogation of SAMSN1's regulatory effects on essential macrophage functions, including cell proliferation and phagocytic capacity. The mechanism of SAMSN1 in the interaction between macrophages and T cells was investigated using the RAW264.7 cell line and primary cell lines.

RESULTS

SAMSN1 expression was significantly increased in patients with sepsis and was positively correlated with sepsis mortality. Genetic deletion of Samsn1 in murine sepsis model improved T cell survival, elevated T cell cytolytic activity, and activated T cell signaling transduction. Concurrently, Samsn1 knockout augmented macrophage proliferation capacity and phagocytic efficiency. In macrophage, SAMSN1 binds to Kelch-like epichlorohydrin-associated protein 1 (KEAP1), causing nuclear factor erythroid 2-related factor 2 (NRF2) to dissociate from the KEAP1-NRF2 complex and translocate into the nucleus. This promotes the transcription of the coinhibitory molecules CD48/CD86/carcinoembryonic antigen related cell adhesion molecule 1 (CEACAM1), which bind to their corresponding receptors natural killer cell receptor 2B4 (2B4)/CD152/T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) on the surface of T cells, inducing T-cell exhaustion.

CONCLUSIONS

SAMSN1 deletion augmented adaptive T cell immunity and macrophage phagocytic-proliferative dual function. Furthermore, it mediates the KEAP1-NRF2 axis, which affects the expression of coinhibitory molecules on macrophages, leading to T-cell exhaustion. This novel immunosuppression mechanism potentially provides a candidate molecular target for sepsis immunotherapy.

Comparative efficacy and prognostic impact of continuous versus intermittent hydrocortisone administration in septic shock patients

This study investigates the effects of continuous versus intermittent hydrocortisone administration on septic shock patients. Sixty patients were randomized into two groups: one receiving intermittent doses of 50 mg of hydrocortisone every 6 h and the other a continuous infusion of 200 mg/day. After a 7-day treatment period and a 28-day follow-up, we observed no significant differences in the duration of sustained shock, hospital, and ICU stays between the groups. However, those in the continuous infusion group experienced shorter periods of mechanical ventilation and vasopressor use, with significant improvements in hemodynamic stability. Both treatment approaches improved arterial pressure and lactate clearance, with no significant differences in heart rate or cortisol levels between the groups at the end of the treatment. Notably, shock reversal rates were higher and 28-day mortality rates were lower in the continuous infusion group. These results suggest that continuous hydrocortisone infusion may be more effective for managing septic shock, potentially leading to better patient outcomes without an increase in adverse reactions. This method could be considered for broader clinical implementation in septic shock treatment strategies.

The pathogenesis of ventilator-associated pneumonia: old and new mechanisms

INTRODUCTION

Ventilator-associated pneumonia (VAP), defined as a lung infection that occurs in patients after 48 hours on mechanical ventilation, is among the most frequently found nosocomial infections in intensive care units around the world and is associated with increased morbidity, mortality, and economic burden.

AREAS COVERED

We review the classical mechanisms of VAP development and explore more recent ones, such as dysbiosis, which has changed our view of the pathogenesis of the disease; whereas in the past the lower respiratory tract was classically considered a sterile organ, the use of new diagnostic techniques has shown that the lungs of healthy humans are inhabited by a large, dynamic ecosystem of microorganisms. Dysbiosis is the disruption of this ecosystem and is a key factor in the development of VAP. Recent findings have demonstrated that host immunity is microbiome-regulated and, consequently, is profoundly affected by dysbiosis. In this paper the significance of the microbiome-immunity crosstalk in the pathophysiology of VAP will be discussed.

EXPERT OPINION

A deeper understanding of mechanisms of VAP pathogenesis should help to devise new preventive, diagnostic and therapeutic strategies for reducing the incidence of this condition and for improving patient prognosis.

Association between stress hyperglycemia ratio and acute kidney injury development in patients with sepsis: a retrospective study

Background

Stress hyperglycemia ratio (SHR), which adjusts blood glucose levels using glycated hemoglobin to eliminate the influence of chronic hyperglycemia, has been demonstrated to have superior predictive value than absolute hyperglycemia. However, its predictive value for sepsis-associated acute kidney injury (SA-AKI) remains unclear. This study aimed to investigate the relationship between the SHR and the risk of developing SA-AKI.

Methods

Data were extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Restricted cubic splines (RCS) were employed to depict the relationship between SHR and the likelihood of SA-AKI, determining an optimal cut-off value. Based on this threshold, patients were categorized into two groups. Logistic regression was utilized to evaluate SHR's predictive value for SA-AKI, with adjustments for confounding variables. Propensity score matching (PSM) was applied to balance baseline characteristics. Subgroup and sensitivity analyses were conducted.

Results

A total of 2,249 patients were included. The RCS curve indicated a non-linear positive association between SHR and the likelihood of SA-AKI (P for non-linearity < 0.001), with an optimal cut-off at 1.55. Accordingly, patients were divided into SHR ≤ 1.55 and SHR > 1.55 subgroups, comprising 1,131 and 1,118 individuals, respectively. A higher incidence of SA-AKI was observed in the SHR > 1.55 group (38.64% vs. 27.23%, P < 0.001). This association persisted after baseline adjustment through PSM. Logistic regression analysis confirmed that SHR > 1.55 was linked to increased odds of SA-AKI in both unadjusted (OR: 1.68, P < 0.001) and adjusted models (OR: 1.73, P < 0.001), with SHR ≤ 1.55 serving as the reference. In subgroup analysis, all subgroups consistently demonstrated a significant association between SHR > 1.55 and elevated odds of SA-AKI (all OR > 1). Sensitivity analysis validated that SHR > 1.55 remained significantly correlated with SA-AKI occurrence in the survival subgroup (OR: 1.46, P < 0.001) and the non-CKD subgroup (OR: 1.69, P < 0.001).

Conclusion

The findings indicate a non-linear positive relationship between SHR and the likelihood of SA-AKI in patients with sepsis, suggesting that SHR could be a potential predictor for SA-AKI.

Diagnostic and Prognostic Value of Hematological Parameters in Necrotizing Enterocolitis: A Systematic Review

Background/Objectives: Necrotizing enterocolitis (NEC) is a severe, potentially fatal gastrointestinal disease that primarily affects preterm neonates, especially those with very low birth weight (<1500 g). Despite extensive research, its pathophysiology remains unclear, with NEC considered a spectrum of disorders driven by systemic inflammation, microbiota dysregulation, and intestinal hypoxic injury. Diagnosis is challenging due to its subtle presentation and reliance on clinical and radiographic findings, underscoring the urgent need for reliable early biomarkers. Complete blood count (CBC) is one of the most frequently performed laboratory tests in neonatal care, providing valuable insights associated with hematologic alterations associated with NEC. Given its cost-effectiveness, accessibility, and rapid turnaround time, CBC parameters have been increasingly investigated for their diagnostic and prognostic potential in NEC. This systematic review consolidates existing evidence on the diagnostic and prognostic utility of CBC parameters in NEC, examining their association with disease onset, progression, and outcomes. Methods: A systematic review of the literature in PubMed and Scopus databases was conducted, between February 25 and December 2024. Results: Following a PRISMA-compliant search strategy, 77 eligible studies were included, analyzing data from 295,195 neonates, of whom 14,570 had NEC. Among the 77 studies, 17 examined NEC-associated mortality as a primary outcome, while 13 studies focused on the development of predictive models incorporating CBC parameters alongside other clinical and laboratory data to assess NEC severity and prognosis in neonates. The findings highlight the potential of CBC-derived markers to facilitate early NEC detection and risk stratification. However, variations in study design and diagnostic criteria highlight the need for prospective studies to validate their clinical use. Conclusions: Despite advancements in understanding NEC, its diagnosis remains challenging due to the absence of fully reliable biomarkers. CBC parameters show promise in offering early diagnostic and prognostic insights. However, further validation is needed for their routine integration into NICU practice. Given the persistent challenges in NEC diagnosis and management, our findings highlight the necessity for integrated scoring systems that combine hematologic, clinical, and radiologic data to enhance early detection and optimize neonatal care. Further research is essential to refine these predictive models, enabling timely interventions and improving survival rates in NEC-affected neonates.

WHOLE TRANSCRIPTION ANALYSIS IDENTIFIED THE REGULATION OF HYPOXIA-INDUCIBLE FACTORS IN MONOCYTES WITH IMMUNE SUPPRESSION: IMPLICATIONS FOR CLINICAL OUTCOMES

ABSTRACT

Aims: Sepsis progression is marked by a complex immune response, where the involvement of hypoxia-inducible factors (HIFs) plays an uncertain role. The study aims to elucidate the involvement of HIF-1α in monocyte function during sepsis and its potential as a prognostic indicator. Methods and Results: Transcriptomic data from healthy individuals and septic patients in datasets GSE54514, GSE167363, and GSE46955 were analyzed. Additionally, human monocytes were employed to elucidate how HIF regulates immune responses in the context of sepsis. Septic nonsurvivors exhibited sustained upregulation of HIF-1α expression alongside compromised inflammatory response and antigen presentation, with downregulation of NF-κB and HLADRB1 genes associated with poor sepsis prognosis. Conversely, septic survivors displayed an increased proportion of classical monocytes and enhanced inflammation and expression of antigen presentation-related genes. During the recovery phase of sepsis, monocytes continued to demonstrate elevated HIF-1α expression. In cultured THP1 cells and septic CD14 + monocytes, HIF hindered inflammatory responses and antigen presentation, while also suppressing the proportion of classical monocytes after LPS stimulation. Mechanistically, HIF significantly attenuated LPS-induced immune responses in monocytes by inhibiting the phosphorylation of IKK. Conclusions: HIF in monocytes acts as a suppressor of immune-inflammatory responses and antigen presentation, and may serve as a negative molecular marker for sepsis development.

PLATELET TRAITS AND SEPSIS RISK AND PROGNOSIS: A BIDIRECTIONAL TWO-SAMPLE MENDELIAN RANDOMIZATION STUDY

ABSTRACT

Background: Sepsis is a critical medical condition characterized by a dysregulated host response to infection. Platelet abnormalities frequently manifest in sepsis patients, but the causal role of platelets in sepsis remains unclear. This study employed a bidirectional two-sample Mendelian randomization (MR) approach to investigate the causal direction between platelets and sepsis. Methods: MR analysis was used to investigate the causal effect of four platelet traits-platelet count (PLT), platelet crit (PCT), mean platelet volume (MPV), and platelet distribution width (PDW)-on sepsis risk and prognosis. Additionally, the study explored the reverse causality, assessing the impact of sepsis on these platelet traits. Genetic variants from large-scale genome-wide association studies served as instrumental variables to infer causality. Sensitivity analyses and heterogeneity tests were conducted to ensure the validity and robustness of the results. Results: Genetically predicted decreased PCT (OR = 0.938, P = 0.044) and MPV (OR = 0.410, P = 0.006) were associated with an increased risk of sepsis. In the reverse direction, 28-day sepsis mortality was significantly associated with decreased PLT (OR = 0.986, P = 0.034). No significant causal relationships were observed between sepsis and other platelet traits. Conclusions: This study suggests a causal association between low PCT and MPV levels and increased risk of sepsis. Additionally, sepsis with a poor prognosis was causally linked to decreased PLT. These findings provide novel evidence for the causal relationship between platelet traits and sepsis.

A Dual-Pipeline Lactate Removal Strategy to Reverse Vascular Hyperpermeability for the Management of Lipopolysaccharide-Induced Sepsis

Sepsis is an underappreciated yet severe threat to human life, marked by organ dysfunction and high mortality resulting from disordered inflammatory responses to blood infection. Unfortunately, no specific drugs are available for effective sepsis treatment. As a pivotal biomarker for sepsis, lactate levels are closely related to vascular permeability and sepsis-associated mortality. Herein, a dual-pipeline lactate removal strategy is reported from circulating blood to ameliorate vascular permeability and lipopolysaccharide (LPS)-induced sepsis. This is achieved by formulating lactate oxidase (LOX)-encapsulated hollow manganese dioxide (HMnO2) nanohybrids (LOX@HMnO2-P[5]A) bearing pillar[5]arene (P[5]A) macrocycle with excellent host-guest properties. The highly biocompatible nanohybrids enable direct lactate consumption through LOX catalytic degradation and block lactate production by P[5]A-mediated LPS trapping, allowing for dual-pipeline lactate removal to maximize the reversal of lactate-mediated vascular hyperpermeability. Besides, HMnO2 cores decompose hydrogen peroxide produced from lactate oxidation into oxygen, further contributing to lactate consumption and mitigating the hypoxic inflammatory environment. In vivo investigations demonstrate that intravenous administration of LOX@HMnO2-P[5]A nanohybrids with extended blood circulation can effectively ameliorate endothelial barrier dysfunction, inflammatory responses, and multiple organ injury, ultimately improving survival outcomes in LPS-induced sepsis. Taken together, this dual-pipeline lactate removal strategy offers a promising approach for efficient sepsis treatment.

PD-L1+ plasma cells suppress T lymphocyte responses in patients with sepsis and mouse sepsis models

Sepsis, a leading cause of death in intensive care units, is associated with immune alterations that increase the patients' risk of secondary infections and mortality, so better understandings of the pathophysiology of sepsis-induced immunosuppression is essential for the development of therapeutic strategies. In a murine model of sepsis that recapitulates immune alterations observed in patients, here we demonstrate that PD-L1+CD44+B220LowCD138+IgM+ regulatory plasma cells are induced in spleen and regulate ex vivo proliferation and IFNɣ secretion induced by stimulation of T splenocytes. This effect is mediated both by cell-cell contact through increased PD-L1 expression on plasma cells and by production of a soluble factor. These observations are recapitulated in three cohorts of critically ill patients with bacterial and viral sepsis in association with increased mortality. Our findings thus reveal the function of regulatory plasma cells in the pathophysiology of sepsis-induced immune alterations, and present a potential therapeutic target for improving immune cell function impaired by sepsis.

Inhibitory Immune Checkpoints Predict 7-Day, In-Hospital, and 1-Year Mortality of Internal Medicine Patients Admitted With Bacterial Sepsis

BACKGROUND

Sepsis is a life-threatening syndrome with complex pathophysiology and great clinical heterogeneity, which complicates the delivery of personalized therapies. Our goal was to demonstrate that some biomarkers identified as regulatory immune checkpoints in preclinical studies could guide the stratification of patients with sepsis into subgroups with shared characteristics of immune response or survival outcomes.

METHODS

We assayed the soluble counterparts of 12 biomarkers of immune response in 113 internal medicine patients with bacterial sepsis.

RESULTS

IL-1 receptor-associated kinase M (IRAK-M) exhibited the highest hazard ratios (HRs) for increased 7-day (1.94; 95% confidence interval [CI], 1.17-3.20) and 30-day mortality (1.61; 95% CI, 1.14-2.28). HRs of IRAK-M and galectin-1 for predicting 1-year mortality were 1.52 (95% CI, 1.20-1.92) and 1.64 (95% CI, 1.13-2.36), respectively. Patients with elevated serum levels of IRAK-M and galectin-1 had clinical traits of immune suppression and low survival rates.

CONCLUSIONS

Two inhibitory immune checkpoint biomarkers (IRAK-M and galectin-1) helped identify 3 distinct sepsis phenotypes with distinct prognoses. These biomarkers shed light on the interplay between immune dysfunction and prognosis in patients with bacterial sepsis and may prove to be useful prognostic markers, therapeutic targets, and biochemical markers for targeted enrollment in therapeutic trials.

A Usefulness of Delta Neutrophil Index (DNI) for Prediction of 28 Day Mortality in Patients with Pneumonia-Induced Sepsis in the Intensive Care Unit

Background: The delta neutrophil index (DNI) represents the immature granulocyte fraction and is determined by subtracting the fraction of mature polymorphonuclear leucocytes from the sum of myeloperoxidase-reactive cells. The DNI has been proposed as a useful prognostic marker for sepsis. This study evaluated the clinical utility of DNI as a predictive marker in patients with pneumonia-induced sepsis in the intensive care unit (ICU). Methods: We conducted a retrospective study of pneumonia-induced sepsis in patients who were admitted to the Kangdong Sacred Heart Hospital's medical ICUs from July 2022 to March 2024. The DNI was measured on three consecutive days after ICU admission. The primary outcome of this study was a 28-day mortality. Results: A total of 227 patients with pneumonia-induced sepsis were included in this study. A 28-day mortality occurred 20.3% of the time in our study. In a univariate analysis, age (p = 0.05), lymphocyte (p = 0.02), DNI 1 (p = 0.01), DNI 2 (p = 0.00), DNI 3 (p = 0.00), and lactic acid (p = 0.00) were significantly associated with 28-day mortality. In a multivariable analysis, lactate (adj. OR: 0.86, 95% CI: 0.78-0.95, p = 0.002), and DNI 3 (adj. OR: 0.94, 95% CI: 0.89-0.99, p = 0.048) were significantly associated with 28-day mortality. In our study, the most appropriate cut-off values were DNI 1 (7.15), DNI 2 (8.9), and DNI 3 (2.6). Patients with higher DNI 3 (≥2.6) showed higher 28-day mortality than patients with lower DNI 3 values of <2.6 (67.4% vs. 32.6%; p < 0.001). However, those aged ≥70 did not show statistically significantly different DNI 1 values between the survivor and non- survivor groups. Conclusions: The DNI at 72 h after ICU admission is a promising predictive prognostic marker of 28-day mortality in patients with pneumonia-induced sepsis in the ICU. However, the interpretation of the DNI in sepsis patients aged 70 and older on the first day of hospitalization should be approached with caution.

Advancing sepsis diagnosis and immunotherapy machine learning-driven identification of stable molecular biomarkers and therapeutic targets

Sepsis represents a significant global health challenge, necessitating early detection and effective treatment for improved outcomes. While traditional inflammatory markers facilitate the diagnosis of sepsis, the aspect of immune suppression remains poorly addressed. This study aimed to identify critical immune-related genes (IIRGs) associated with sepsis through genomic analysis and machine learning techniques, thereby enhancing diagnostic and treatment response predictions. Analyses of two extensive datasets were conducted, identifying significant immune genes using the ESTIMATE algorithm, Weighted Gene Correlation Network Analysis (WGCNA), and five machine learning methods. Prediction models were constructed and validated using six machine learning algorithms, achieving high accuracy (AUC > 0.75). Eleven key IIRGs were identified as active in immune pathways, such as the JAK-STAT signaling pathway, and were significantly correlated with immune cell infiltration in sepsis. Additionally, drug sensitivity analysis indicated that IIRGs correlated with responses to anticancer drugs. These results underscore the potential of these genes in enhancing sepsis diagnosis and treatment, highlighting the imperative for further validation across diverse populations.

The relationship between hemoglobin, albumin, lymphocyte, and platelet (HALP) score and 28-day mortality in patients with sepsis: a retrospective analysis of the MIMIC-IV database

BACKGROUND

In recent years, the hemoglobin, albumin, lymphocyte, and platelet (HALP) score has emerged as a potential marker of immunological and nutritional status. This study aimed to evaluate the association between the HALP score and prognosis in patients with sepsis.

METHODS

This retrospective cohort study analyzed sepsis patients using clinical data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Patients were classified into Low-score and High-score groups. Confounding factors were controlled through propensity score matching (PSM) analysis. The primary outcome was 28-day mortality in individuals with sepsis. Survival probabilities between groups were compared using Kaplan-Meier curves. Multivariable Cox regression analysis and a smoothing spline fitting curve were employed to investigate the relationship between the HALP score and 28-day mortality. ROC curve analysis and subgroup analysis were performed to evaluate the predictive ability of the HALP score and its components.

RESULTS

A total of 2,968 sepsis patients were included, with 809 (27.26%) deaths within 28 days. After PSM analysis, the High-score group had a 24% lower risk of 28-day mortality compared to the Low-score group (HR, 0.76; 95% CI, 0.64-0.91). In the unmatched cohort, the multivariable Cox regression model also indicated that the High-score group had a lower 28-day mortality risk (HR, 0.78; 95% CI, 0.67-0.91). The smoothing spline fitting curve showed a nonlinear relationship between the HALP score and 28-day mortality, with an inflection point at 24.69. When the HALP score was below 24.69, an increase of one point in the HALP score was associated with a 2% reduction in 28-day mortality (HR, 0.98; 95% CI, 0.97-0.99). The HALP score provided incremental predictive value for 28-day mortality when combined with the SOFA score. Albumin was identified as the most influential component of the HALP score.

CONCLUSION

Among patients with sepsis, the HALP score exhibited a nonlinear relationship with 28-day mortality. An elevated HALP score is associated with reduced 28-day, 90-day, 360-day, and in-hospital mortality among sepsis patients.

Comprehensive integration of diagnostic biomarker analysis and immune cell infiltration features in sepsis via machine learning and bioinformatics techniques

Introduction

Sepsis, a critical medical condition resulting from an irregular immune response to infection, leads to life-threatening organ dysfunction. Despite medical advancements, the critical need for research into dependable diagnostic markers and precise therapeutic targets.

Methods

We screened out five gene expression datasets (GSE69063, GSE236713, GSE28750, GSE65682 and GSE137340) from the Gene Expression Omnibus. First, we merged the first two datasets. We then identified differentially expressed genes (DEGs), which were subjected to KEGG and GO enrichment analyses. Following this, we integrated the DEGs with the genes from key modules as determined by Weighted Gene Co-expression Network Analysis (WGCNA), identifying 262 overlapping genes. 12 core genes were subsequently selected using three machine-learning algorithms: random forest (RF), Least Absolute Shrinkage and Selection Operator (LASSO), and Support Vector Machine-Recursive Feature Elimination (SVW-RFE). The utilization of the receiver operating characteristic curve in conjunction with the nomogram model served to authenticate the discriminatory strength and efficacy of the key genes. CIBERSORT was utilized to evaluate the inflammatory and immunological condition of sepsis. Astragalus, Salvia, and Safflower are the primary elements of Xuebijing, commonly used in the clinical treatment of sepsis. Using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), we identified the chemical constituents of these three herbs and their target genes.

Results

We found that CD40LG is not only one of the 12 core genes we identified, but also a common target of the active components quercetin, luteolin, and apigenin in these herbs. We extracted the common chemical structure of these active ingredients -flavonoids. Through docking analysis, we further validated the interaction between flavonoids and CD40LG. Lastly, blood samples were collected from healthy individuals and sepsis patients, with and without the administration of Xuebijing, for the extraction of peripheral blood mononuclear cells (PBMCs). By qPCR and WB analysis. We observed significant differences in the expression of CD40LG across the three groups. In this study, we pinpointed candidate hub genes for sepsis and constructed a nomogram for its diagnosis.

Discussion

This research not only provides potential diagnostic evidence for peripheral blood diagnosis of sepsis but also offers insights into the pathogenesis and disease progression of sepsis.

The Novel Role of the Expression of Toll-like Receptors TLR-5, TLR-6, and TLR-9 and Associated Up-Regulation of Programmed Cell Death 1 Receptor (PD-1) and Its Ligand (PD-L1) in Lung Sepsis

Sepsis is a leading cause of death in hospitalized patients. The underlying pathophysiologic mechanisms of sepsis have not been fully elucidated thus far. The receptor of programmed cell death 1 (PD-1) and its ligand (PD-L1), in combination with the Toll-like receptors (TLRs), seem to contribute considerably in systematic responses during sepsis. Investigating the relationship between them and identifying potential target pathways is important in the future management of sepsis, especially in relation to acute lung injury. This study investigated the interactions between TLR-5, -6, and -9 and PD-1/PD-L1 expression in a septic mouse model. Sixty C57BL/6J mice were included and categorized in six study groups. Three sepsis (S) groups (24 h, 48 h, and 72 h) and three sham (Sh) groups (24 h, 48 h, and 72 h) were created. Cecal ligation and puncture (CLP) was utilized to simulate sepsis in the S groups. Hematological analysis and lung tissue histopathological analysis were performed after 24 h, 48 h, and 72 h. Significant decreases in S groups compared to Sh groups in WBC and lymphocyte counts at 24, 48, and 72 h were observed. Significant increases in S groups compared to Sh groups in RBC and monocyte counts, IL-6 and IL-10 levels, alveolar flooding, and alveolar collapse were demonstrated by histopathological analysis. This study suggested a strong correlation between TLR expression and PD-1/PD-L1 up-regulation in lung tissue during sepsis. These molecules, also, seem to contribute to the histopathological changes in lung tissue during sepsis, leading to acute lung injury.

Lianhua Qingke Tablet in severe pneumonia: Clinical efficacy and immunoregulatory mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Lianhua Qingke (LHQK), a traditional Chinese medicine, has shown efficacy in treating acute and chronic bronchitis and bronchiolitis. However, the specific mechanism underlying the therapeutic effects of LHQK on severe pneumonia is not clear.

AIM OF THE STUDY

Severe pneumonia remains a critical health challenge, particularly in cases progressing to sepsis and septic shock, where host immune responses become dysregulated or dysfunctional. This study aims to evaluate the immunomodulatory effects of LHQK in severe pneumonia.

MATERIALS AND METHODS

This research examined LHQK's therapeutic and immunomodulatory mechanisms in patients with severe pneumonia and a lipopolysaccharide (LPS)-induced mouse model of severe pneumonia. Patients with severe pneumonia were randomized into three groups: basal treatment, LHQK-Low dose (12 tablets/day), and LHQK-High dose (24 tablets/day). BALB/c mice were categorized into four groups: control, model, LHQK-Low dose (3.7 mg/kg), and LHQK-High dose (7.4 mg/kg). Clinical efficacy was evaluated by assessing parameters including the value and rate of change in APACHE II score, improvement in chest X-ray or CT, partial pressure of oxygen (PO2), oxygen saturation in arterial blood (SaO2), oxygenation index (OI), and the length of hospitalization after 7 days of treatment. The viscosity of sputum was measured by viscosimeter. Moreover, lung histopathology, airway barrier integrity, and immune cells in BALF, were assessed using hematoxylin and eosin staining, immunostaining, and Wright-Giemsa staining. Cytokine levels were measured using Luminex assay and Olink, while pulmonary immune cell patterns were analyzed using multiplex fluorescence and Cytometry by Time-Of-Flight (CyTOF).

RESULTS

In comparison to the basal treatment group of patients, LHQK treatment exhibited a reduction in the severity of severe pneumonia and inflammatory status, as evidenced by observations on Chest X-ray or CT scans. Additionally, LHQK treatment led to an elevation in OI, PO2, and SaO2 levels, and notably, a decreased duration of hospitalization. Further analysis revealed that LHQK enhanced the integrity of the airway epithelial barrier, reduced the viscosity of sputum, and significantly decreased inflammatory cells infiltration. The application of Luminex and Olink assay further confirmed the inhibitory impact of LHQK on the cytokine storm in mice. Moreover, multiplex fluorescence and CyTOF analysis demonstrated that LHQK effectively suppressed the activation of monocyte derived macrophages, neutrophils, and Treg cells, while preserved the levels of alveolar macrophages, B cells, and CD4+ and CD8+ T lymphocytes, therefore restoring immune homeostasis within the lung of severe pneumonia. These findings significantly substantiate the potential clinical application of LHQK in severe pneumonia treatment.

CONCLUSION

LHQK demonstrates therapeutic efficacy in severe pneumonia by maintaining structural integrity, suppressing cytokine storms, enhancing intrinsic immunity, reversing T cell exhaustion, and correcting lung immune disorders. These findings significantly substantiate LHQK's potential clinical application in severe pneumonia treatment.

Macrophage memory emerges from coordinated transcription factor and chromatin dynamics

Cells of the immune system operate in dynamic microenvironments where the timing, concentration, and order of signaling molecules constantly change. Despite this complexity, immune cells manage to communicate accurately and control inflammation and infection. It is unclear how these dynamic signals are encoded and decoded and if individual cells retain the memory of past exposure to inflammatory molecules. Here, we use live-cell analysis, ATAC sequencing, and an in vivo model of sepsis to show that sequential inflammatory signals induce memory in individual macrophages through reprogramming the nuclear factor κB (NF-κB) network and the chromatin accessibility landscape. We use transcriptomic profiling and deep learning to show that transcription factor and chromatin dynamics coordinate fine-tuned macrophage responses to new inflammatory signals. This work demonstrates how macrophages retain the memory of previous signals despite single-cell variability and elucidates the mechanisms of signal-induced memory in dynamic inflammatory conditions like sepsis.

Identification of diagnostic biomarkers related to the efferocytosis pathway and immune cell infiltration characteristics in pediatric sepsis by bioinformatics analysis

Pediatric sepsis is a serious disease characterized by multiple organ failure. Due to its unique pathogenesis, its clinical mortality rate is very high. This study systematically evaluated the value of efferocytosis related genes in the diagnosis of sepsis in children. We downloaded gene expression profiles related to pediatric sepsis from the gene expression omnibus database, identify differentially expressed genes (DEGs) by limma R package, and retrieve adult sepsis gene expression profiles to determine the specificity of pediatric sepsis biomarkers. Selected pediatric sepsis specific genes from these profiles and used clusterProfiler for Kyoto Encyclopedia of Genes and Genomes (KEGG), gene ontology, and Reactome databases for functional enrichment. Genesets related to Efferocytosis was searched in the KEGG database, and the intersection with pediatric sepsis specific genes was considered as pediatric sepsis-efferocytosis genes. Immune infiltration analysis was performed using the CIBERSORT package. Constructed a protein-protein interaction (PPI) network and screened for hub genes in pediatric sepsis-efferocytosis genes. Further select diagnostic markers through gene expression and receiver operating characteristic (ROC) curve. We identified a total of 281 DEGs specific to pediatric sepsis, which are enriched in pathways such as phagosome, autophagy and efferocytosis. We found that the efferocytosis pathway is significantly up-regulated in pediatric sepsis, while this pathway is not significant in adult sepsis. We noticed that 12 types of immune cells infiltration levels including macrophages in pediatric sepsis patients. We selected the top 20 hub genes with PPI network. By overlapping hub genes with pediatric sepsis-efferocytosis genes, we obtained 2 hub pediatric sepsis-efferocytosis genes (ALOX5, CD36). The ROC curve suggested that these genes may be potential diagnostic markers for pediatric sepsis. We have identified ALOX5 and CD36 as efferocytosis related genes associated with pediatric sepsis, which can reliably identify pediatric sepsis and provide prospective clinical references for the pathogenesis of pediatric sepsis.

The tryptophan metabolite kynurenic acid ameliorates septic colonic injury through activation of the PPARγ signaling pathway

Sepsis is the leading cause of death among critically ill patients in clinical practice, making it urgent to reduce its incidence and mortality rates. In sepsis, macrophage dysfunction often worsens and complicates the condition. M1 and M2 macrophages, two distinct types, contribute to pro-inflammatory and anti-inflammatory effects, respectively. An imbalance between them is a major cause of sepsis. The aim of this study was to explore the potential of a differential metabolite between M1 and M2 macrophages in mitigating septic colonic injury via multiomics in combination with clinical data and animal experiments. Using nontargeted metabolomics analysis, we found that Kynurenic acid (KYNA), a metabolite of tryptophan metabolism, was significantly upregulated in the supernatant of M2 macrophages. Furthermore, we discovered that the level of KYNA was significantly decreased in sepsis in both human and mouse serum and was negatively correlated with inflammatory factor levels. In vivo experiments demonstrated that KYNA can effectively alleviate septic colon injury and reduce inflammatory factor levels in mice, indicating that KYNA plays a very important protective role in sepsis. Mechanistically, KYNA promotes the transition of M1 macrophages to M2 macrophages by inhibiting the NF-κB signaling pathway and alleviates septic colonic injury through the PPARγ/NF-κB axis. This article reveals that KYNA, a differentially abundant metabolite between M1 and M2 macrophages, can become a new strategy for alleviating septic colon injury.

Dynamic changes in peripheral blood lymphocyte trajectory predict the clinical outcomes of sepsis

Background

Sepsis induces profound derangements in the immune system, including lymphopenia, which correlates with immunosuppression and poor prognosis. However, most evaluations of immunosuppression in sepsis patients rely on static, sporadic lymphocyte counts, lacking dynamic modeling over the disease course. This study aimed to apply latent class mixed modeling on longitudinal lymphocyte counts to uncover heterogeneous trajectory phenotypes in sepsis patients and assess their predictive value for clinical outcomes.

Results

Four lymphocyte trajectory phenotypes were identified in the retrospective cohort (n=2,149) and externally validated (n=2,388): high-declining (α, 3.8%), stable-medium (β, 69.3%), high-increasing (γ, 3.2%), and stable-low (δ, 23.8%). The α phenotype exhibited the highest disease severity and mortality (25.9%) compared with other phenotypes in both cohorts. In the prospective cohort (n=1,056), all lymphocyte subset counts differed among phenotypes on admission (P <.001) and were lower in non-survivors (P<.05). Multivariable regression demonstrated that age, Acute Physiology and Chronic Health Evaluation-II score, heart rate, natural killer cell count, infection source, and lymphocyte trajectory phenotype were independent predictors of 28-day mortality. A nomogram combining these variables provided individualized risk estimations.

Conclusions

The lymphocyte trajectories delineated novel dynamic phenotypes associated with divergent sepsis outcomes. Incorporating longitudinal trajectory modeling and lymphocyte subsets may improve prognostic risk assessment and guide the selection of immunotherapies tailored to specific immune phenotypes in sepsis patients.

Clinical trial registration

https://www.chictr.org.cn/showproj.aspx?proj=18277, identifier ChiCTR-40 ROC-17010750.

Epigenome-wide DNA methylation profiling in septic and non-septic patients with similar infections: potential use as sepsis biomarkers

Introduction

Sepsis is a life-threatening condition caused by a dysregulated immune response to infection, leading to organ failure. Despite its significant global burden, the underlying mechanisms of immune dysfunction in sepsis remain incompletely understood. This study explores the role of DNA methylation in white blood cells in sepsis pathogenesis.

Methods

A prospective case-control study was conducted to compare DNA methylation profiles between patients with community-acquired sepsis and matched controls who had similar infections but did not develop sepsis. Whole blood samples from these patients were analyzed using the Infinium MethylationEPIC v2.0 kit, enabling genome-wide methylation analysis. Selected genes with differential methylation were validated by pyrosequencing.

Results

Significant differential DNA methylation patterns were identified between septic and non-septic individuals uising. Our results suggest that DNA methylation changes are closely linked to the pathophysiological processes of sepsis, influencing immune cell activation, inflammation, and organ dysfunction. The most prominent findings include the hypomethylation of immune-related genes (SERPINA1, AZU1, MPO, and SLX4), which were strongly correlated with clinical severity and inflammatory markers such as SOFA scores and PCT levels. Correlation analyses demonstrated significant associations between the methylation levels of these genes and clinical severity markers, such as SOFA score and PCT levels. Notably, SLX4 hypomethylation showed the highest predictive value for poor prognosis (AUC 0.821), while SERPINA1 hypomethylation exhibited strong diagnostic potential for sepsis (AUC 0.858).

Discussion

Our results underscore the potential of DNA methylation changes, particularly in immune-related genes, to enhance the early detection of sepsis and to stratify patients based on severity. Future research should explore the therapeutic implications of these epigenetic alterations in sepsis care.

Association between various blood glucose variability-related indicators during early ICU admission and 28-day mortality in non-diabetic patients with sepsis

BACKGROUND

Various blood glucose (BG) variability-related indexes have been widely used to assess glycemic control and predict glycemic risks, but the association between BG variations and prognosis in non-diabetic patients with sepsis remains unclear.

METHODS

The single-center retrospective cohort study included 7,049 non-diabetic adults with sepsis who had at least 3 records of bedside capillary point of care BG testing during the first day after ICU admission from MIMIC-IV database (2008 to 2019). Coefficient of variation and standard deviation of glucose (i.e., GluCV and GluSD), M-value, J-index, high blood glucose index (HBGI), and low blood glucose index (LBGI) were used to describe glucose variability, quality of glycemic control, and glycemic risk of patients with sepsis. The dose-response relationship between BG variability-related indexes and mortality was explored using multivariate logistic regression with restricted cubic spline (RCS) function. If the dose-response curve presented a J-shape with a specific threshold value, a linear threshold function instead of RCS would be employed.

RESULTS

There is a J-shaped relationship between hospital mortality risk and glucose variability-related indexes in ICU patients with sepsis. The mortality risk remained relatively stable below the threshold of these indexes. However, over the threshold, the 28-day mortality risk increased by 2.82% (95% CI: 1.80-3.85%), 1.13% (95% CI: 0.66-1.60%), 1.96% (95% CI: 0.98-2.95%), 1.37% (95% CI: 0.57-2.16%), 11.19% (95% CI: 6.56-15.98%) and 39.04% (95% CI: 29.86-48.81%) for each unit increases in GluCV, GluSD, M-value, J-index, LBGI and HBGI, respectively. The effects of LBGI and HBGI on 7-day and 14-day mortality were more pronounced.

CONCLUSIONS

High levels of GluCV, GluSD, M-value, J-index, HBGI, and LBGI on the first day of ICU admission were important risk markers of hospital mortality among non-diabetic patients with sepsis.

Recent advances of precision immunotherapy in sepsis

Precision immunotherapy signifies the administration of the required type of immune intervention tailored to the state of immune activation at the appropriate time window. The classification of patients into the different states of immune activation is usually done by either a protein blood biomarker or a molecular blood endotype that is diagnostic of the precise immune state. Evidence coming from trials of the last decade suggests that immune interventions should be split into strategies aiming to attenuate the exaggerated immune responses, restore sepsis-induced immunoparalysis (SII) and restore the vascular tone. Suggested strategies to attenuate the immune responses are anakinra, nangibotide and tocilizumab. Biomarkers that guide their use are ferritin, soluble triggering receptor expressed on myeloid cells-1 and C-reactive protein. Suggested strategies to restore SII are nivolumab, recombinant human interferon-gamma, CYT107, granulocyte macrophage colony stimulating factor and IgM-enriched immunoglobulin prepapations. Biomarkers that guide their use are the expression of the human leukocyte antigen DR on blood monocytes, the absolute lymphocyte count and blood levels of immunoglobulin M. One recently suggested strategy to restore vascular tone is adrecizumab, the use of which is guided by blood levels of bio-adrenomedulin. The use of these precision treatment strategies is still hampered by the need for large-scale randomized controlled trials.

Macrophage polarization in sepsis: Emerging role and clinical application prospect

Sepsis is a severe, potentially fatal condition defined by organ dysfunction due to excessive inflammation. Its complex pathogenesis and poor therapeutic outcomes pose significant challenges in treatment. Macrophages, with their high heterogeneity and plasticity, play crucial roles in both the innate and adaptive immune systems. They can polarize into M1-like macrophages, which promote pro-inflammatory responses, or M2-like macrophages, which mediate anti-inflammatory responses, positioning them as critical mediators in the immune response during sepsis.Macrophages are the main regulators of inflammatory responses, and their polarization is also regulated by inflammatory signaling pathways. This review highlights recent advances in the inflammatory signaling pathways involved in sepsis, mechanism of macrophage polarization mediated by inflammation-related signaling pathways in sepsis, and the role of signaling pathway mediated macrophage polarization in organ dysfunction involved in sepsis. We also explore the therapeutic potential of targeting macrophage polarization for immunotherapy, offering new perspectives on macrophage-targeted treatments for sepsis.

TRPM2 deficiency contributes to M2b macrophage polarization via the PI3K/AKT/CREB pathway in murine sepsis

BackgroundPrevious studies suggest that transient receptor potential melastatin 2 (TRPM2) plays a protective role in sepsis by enhancing bacterial clearance. This effect is mediated through the modulation of macrophage phenotypic changes, which strengthen the immune response against infection. However, the specific role and underlying mechanism of TRPM2 in macrophage polarization during sepsis remain unclear.MethodCecal ligation and puncture (CLP) was used to establish a mouse sepsis model, and bone marrow-derived macrophages (BMDMs) and peritoneal macrophages were prepared from C57BL/6 wild-type and TRPM2 knockout (trpm2-/-) mice. IPI549 was utilized as a specific inhibitor of PI3K. Macrophage polarization, bactericidal ability, and the PI3K/protein kinase B (AKT)/cyclic adenosine monophosphate response element-binding protein signaling pathway were assessed. In addition, survival rate, bacterial burden, lung wet/dry weight ratio, lung and liver injury scores, and cytokine levels were measured in CLP-induced septic mice.ResultsIn lipopolysaccharide (LPS)-stimulated BMDMs, trpm2 deficiency increased the expression of characteristic markers associated with the M2b phenotype, reduced the bactericidal ability, and activated the PI3K/AKT/CREB signaling pathway. Consequently, both trpm2-/- BMDMs and trpm2-/- mice exhibited impaired bactericidal clearance during CLP-induced sepsis. Furthermore, IPI549 attenuated TRPM2 deletion-induced M2b polarization and restored the bactericidal function of BMDMs. Notably, IPI549 preconditioning reversed the increased susceptibility of the trpm2-/- mice to sepsis. The 7-day mortality rate was 92% in trpm2-/- mice, compared to 42% in IPI549-pretreated trpm2-/- mice. Moreover, IPI549-treated mice exhibited improved lung wet/dry ratios, reduced lung and liver injury scores, reversed M2b polarization and decreased bacterial load.ConclusionThe PI3K/AKT/CREB pathway mediates the effect of TRPM2 by inhibiting M2b macrophage polarization and promoting bacterial clearance during sepsis.

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.

The Role of Immune Semaphorins in Sepsis-A Prospective Cohort Study

In sepsis, a balanced pro-inflammatory and anti-inflammatory response results in the bacterial clearance and resolution of inflammation, promoting clinical recovery and survival. Semaphorins, a large family of secreted and membrane-bound glycoproteins, are newly recognized biomarkers and therapeutic targets in immunological and neoplastic disorders. Although semaphorins might also be a crucial part of host defense responses to infection, their role in sepsis is yet to be determined. This study aimed to analyze the association of serum semaphorin concentrations with sepsis severity and outcomes. Serum semaphorin concentrations (SEMA3A, SEMA3C, SEMA3F, SEMA4D, and SEMA7A) were measured in 115 adult patients with community-acquired sepsis and 50 healthy controls. While SEMA3A was decreased, SEMA3C, SEMA3F, SEMA4D, and SEMA7A were increased in sepsis patients. All analyzed SEMA showed good accuracy in identifying patients with sepsis. SEMA kinetics were related to sepsis complications; SEMA3A, SEMA3C, SEMA3F, and SEMA4D with respiratory failure; SEMA3C and SEMA7A with acute kidney injury; and SEMA3C and SEMA3F were related to septic shock. Importantly, SEMA3A, SEMA3C, SEMA4D, and SEMA7A were associated with 28-day mortality. In conclusion, we provide evidence that semaphorins are associated with sepsis course and outcomes.

Could P2X7 receptor be a potencial target in neonatal sepsis?

The United Nations Inter-Agency Group for Child Mortality Estimation (UNIGME) estimates that every year 2.5 million neonates die in their first month of life, accounting for nearly one-half of deaths in children under 5 years of age. Neonatal sepsis is the third leading cause of neonatal mortality. The worldwide burden of bacterial sepsis is expected to increase in the next decades due to the lack of effective molecular therapies to replace the administration of antibiotics whose efficacy is compromised by the emergence of resistant strains. In addition, prolonged exposure to antibiotics can have negative effects by increasing the risk of infection by other organisms. With the global burden of sepsis increasing and no vaccine nor other therapeutic approaches proved efficient, the World Health Organization (WHO) stresses the need for new therapeutic targets for sepsis treatment and infection prevention (WHO, A73/32). In response to this unresolved clinical issue, the P2X7 receptor (P2X7R), a key component of the inflammatory cascade, has emerged as a potential target for treating inflammatory/infection diseases. Indeed numerous studies have demonstrated the relevance of the purinergic system as a pharmacological target in addressing immune-mediated inflammatory diseases by regulating immunity, inflammation, and organ function. In this review, we analyze key features of sepsis immunopathophysiology focusing in neonatal sepsis and on how the immunomodulatory role of P2X7R could be a potential pharmacological target for reducing the burden of neonatal sepsis.

Association of white blood cell count with one-year mortality after cardiac arrest

Introduction

Post-resuscitation care of cardiac arrest patients may be complicated by systemic inflammation elicited in response to whole-body ischaemia-reperfusion injury. We assessed the association between early WBC with one-year mortality in a large, unselected population of cardiac arrest patients.

Methods

We collected a retrospective multicentre cohort of ICU-treated CA patients from the Finnish national ICU registry. We used locally estimated scatterplot smoothing (LOESS) curve to assess the association between the most abnormal WBC of the first 24 h in the ICU with the likelihood of death within a year. Multivariable logistic regression analyses were performed to assess the independent association between WBC and one-year mortality. In nested cohort analysis, we tested the association of delay from collapse to return of spontaneous circulation (ROSC) with WBC in linear regression models.

Results

The LOESS curve was U-shaped, with the lowest predicted mortality at 7.5 109/L WBC. Based on this cut-off value, patients were divided into high (≥ 7.5 109/L) and low (< 7.5 109/L) WBC groups. In 4229 patients with high WBC, higher WBC was independently associated with increased one-year mortality (adjusted odds ratio (OR) 1.03 per 109/L, 95 % confidence interval (CI) 1.02-1.04, p < 0.001). In 776 patients with low WBC, lower WBC was independently associated with increased one-year mortality (adjusted OR 0.88 per 109/L, 95 % CI 0.80-0.96, p < 0.001). In a nested cohort analysis, longer ROSC-delay was associated with higher WBC in patients with a shockable rhythm (β = 0.10, R2 = 0.04, p < 0.001).

Conclusions

In this large retrospective cohort, WBC was independently associated with one-year mortality after CA. Mortality was lowest in patients with WBC close to the upper limit of the normal reference range. Although WBC is not useful for outcome prognostication in individual patients, our results support the concept of excess inflammation being a harmful component of the post-cardiac arrest syndrome.

Distinct immune profiles and clinical outcomes in sepsis subphenotypes based on temperature trajectories

PURPOSE

Sepsis is a heterogeneous syndrome. Identification of sepsis subphenotypes with distinct immune profiles could lead to targeted therapies. This study investigates the immune profiles of patients with sepsis following distinct body temperature patterns (i.e., temperature trajectory subphenotypes).

METHODS

Hospitalized patients from four hospitals between 2018 and 2022 with suspicion of infection were included. A previously validated temperature trajectory algorithm was used to classify study patients into temperature trajectory subphenotypes. Microbiological profiles, clinical outcomes, and levels of 31 biomarkers were compared between these subphenotypes.

RESULTS

The 3576 study patients were classified into four temperature trajectory subphenotypes: hyperthermic slow resolvers (N = 563, 16%), hyperthermic fast resolvers (N = 805, 23%), normothermic (N = 1693, 47%), hypothermic (N = 515, 14%). The mortality rate was significantly different between subphenotypes, with the highest rate in hypothermics (14.2%), followed by hyperthermic slow resolvers 6%, normothermic 5.5%, and lowest in hyperthermic fast resolvers 3.6% (p < 0.001). After multiple testing correction for the 31 biomarkers tested, 20 biomarkers remained significantly different between temperature trajectories: angiopoietin-1 (Ang-1), C-reactive protein (CRP), feline McDonough sarcoma-like tyrosine kinase 3 ligand (Flt-3l), granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin (IL)-15, IL-1 receptor antagonist (RA), IL-2, IL-6, IL-7, interferon gamma-induced protein 10 (IP-10), monocyte chemoattractant protein-1 (MCP-1), human macrophage inflammatory protein 3 alpha (MIP-3a), neutrophil gelatinase-associated lipocalin (NGAL), pentraxin-3, thrombomodulin, tissue factor, soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), and vascular cellular adhesion molecule-1 (vCAM-1).The hyperthermic fast and slow resolvers had the highest levels of most pro- and anti-inflammatory cytokines. Hypothermics had suppressed levels of most cytokines but the highest levels of several coagulation markers (Ang-1, thrombomodulin, tissue factor).

CONCLUSION

Sepsis subphenotypes identified using the universally available measurement of body temperature had distinct immune profiles. Hypothermic patients, who had the highest mortality rate, also had the lowest levels of most pro- and anti-inflammatory cytokines.

Ubiquitin regulatory X (UBX) domain-containing protein 6 is essential for autophagy induction and inflammation control in macrophages

Ubiquitin regulatory X (UBX) domain-containing protein 6 (UBXN6) is an essential cofactor for the activity of the valosin-containing protein p97, an adenosine triphosphatase associated with diverse cellular activities. Nonetheless, its role in cells of the innate immune system remains largely unexplored. In this study, we report that UBXN6 is upregulated in humans with sepsis and may serve as a pivotal regulator of inflammatory responses via the activation of autophagy. Notably, the upregulation of UBXN6 in sepsis patients was negatively correlated with inflammatory gene profiles but positively correlated with the expression of Forkhead box O3, an autophagy-driving transcription factor. Compared with those of control mice, the macrophages of mice subjected to myeloid cell-specific UBXN6 depletion exhibited exacerbated inflammation, increased mitochondrial oxidative stress, and greater impairment of autophagy and endoplasmic reticulum-associated degradation pathways. UBXN6-deficient macrophages also exhibited immunometabolic remodeling, characterized by a shift to aerobic glycolysis and elevated levels of branched-chain amino acids. These metabolic shifts amplify mammalian target of rapamycin pathway signaling, in turn reducing the nuclear translocation of the transcription factor EB and impairing lysosomal biogenesis. Together, these data reveal that UBXN6 serves as an activator of autophagy and regulates inflammation to maintain immune system suppression during human sepsis.

In response to bacteria, neutrophils release extracellular vesicles capable of initiating thrombin generation through DNA-dependent and independent pathways

Neutrophils release extracellular vesicles, and some subsets of neutrophil-derived extracellular vesicles are procoagulant. In response to Staphylococcus aureus, neutrophils produce extracellular vesicles that associate electrostatically with neutrophil extracellular traps. DNA in neutrophil extracellular traps is procoagulant, but whether neutrophil extracellular vesicles produced during bacterial challenge have similar activity is unknown. Given that extracellular vesicle activity is agonist and cell-type dependent and coagulation contributes to sepsis, we hypothesized that sepsis-causing bacteria increase production of neutrophil-derived extracellular vesicles, as well as extracellular vesicle-associated DNA, and intact extracellular vesicles and DNA cause coagulation. We recovered extracellular vesicles from neutrophils challenged with S. aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa and measured associated DNA and procoagulant activity. Extracellular vesicles from S. aureus-challenged neutrophils, which were previously characterized, displayed dose-dependent procoagulant activity as measured by thrombin generation in platelet-poor plasma. Extracellular vesicle lysis and DNase treatment reduced thrombin generation by 90% and 37%, respectively. S. epidermidis, E. coli, and P. aeruginosa also increased extracellular vesicle production and extracellular vesicle-associated extracellular DNA, and these extracellular vesicles were also procoagulant. Compared to spontaneously released extracellular vesicles, which demonstrated some ability to amplify factor XII-dependent coagulation in the presence of an activator, only extracellular vesicles produced in response to bacteria could initiate the pathway. S. aureus and S. epidermidis extracellular vesicles had more surface-associated DNA than E. coli and P. aeruginosa extracellular vesicles, and S. aureus and S. epidermidis extracellular vesicles contributed to initiation and amplification of thrombin generation in a DNA-dependent manner. However, DNA on E. coli or P. aeruginosa extracellular vesicles played no role, suggesting that neutrophils release procoagulant extracellular vesicles, which can activate the coagulation cascade through both DNA-dependent and independent mechanisms.

Association of Dynamics of Anellovirus Loads With Hospital-Acquired Pneumonia in Patients With Brain Injury During the Intensive Care Unit Stay

BACKGROUND

Critical illness induces immune disorders associated with an increased risk of hospital-acquired pneumonia (HAP) and acute respiratory distress syndrome (ARDS). Torque teno virus (TTV), from the Anelloviridae family, is proposed as a biomarker to measure the level of immunosuppression. Our objective was to describe the kinetics of TTV DNA loads and their association with critical illness-related complications.

METHODS

We performed a longitudinal study in 115 patients with brain injury from a prospective cohort, collected endotracheal and blood samples at 3 successive time points after admission in the intensive care unit (ICU) (T1, 0-4 days post ICU admission; T2, 5-10; T3, 11-18), and measured viral DNA loads using the TTV R-GENE kit (BioMérieux) and a pan-Anelloviridae in-house quantitative real-time polymerase chain reaction.

RESULTS

TTV DNA was detected in the blood of 69%, 71%, and 64% of patients with brain injury at T1, T2, and T3, respectively. Time-associated variations of TTV and anellovirus DNA loads were observed. Using a linear mixed-effects model, we found that HAP and ARDS were associated with lower blood anellovirus DNA loads.

CONCLUSIONS

Our results show that HAP or ARDS in patients who are critically ill is associated with changes in anellovirus DNA loads and should be evaluated further as a biomarker of immune disorders leading to these complications.

Assessing sepsis-induced immunosuppression to predict positive blood cultures

Introduction

Bacteremia is a life-threatening condition that can progress to sepsis and septic shock, leading to significant mortality in the emergency department (ED). The standard diagnostic method, blood culture, is time-consuming and prone to false positives and false negatives. Although not widely accepted, several clinical and artificial intelligence-based algorithms have been recently developed to predict bacteremia. However, these strategies require further identification of new variables to improve their diagnostic accuracy. This study proposes a novel strategy to predict positive blood cultures by assessing sepsis-induced immunosuppression status through endotoxin tolerance assessment.

Methods

Optimal assay conditions have been explored and tested in sepsis-suspected patients meeting the Sepsis-3 criteria. Blood samples were collected at ED admission, and endotoxin (lipopolysaccharide, LPS) challenge was performed to evaluate the innate immune response through cytokine profiling.

Results

Clinical variables, immune cell population biomarkers, and cytokine levels (tumor necrosis factor [TNFα], IL-1β, IL-6, IL-8, and IL-10) were measured. Patients with positive blood cultures exhibited significantly lower TNFα production after LPS challenge than did those with negative blood cultures. The study also included a validation cohort to confirm that the response was consistent.

Discussion

The results of this study highlight the innate immune system immunosuppression state as a critical parameter for sepsis diagnosis. Notably, the present study identified a reduction in monocyte populations and specific cytokine profiles as potential predictive markers. This study showed that the LPS challenge can be used to effectively distinguish between patients with bloodstream infection leading to sepsis and those whose blood cultures are negative, providinga rapid and reliable diagnostic tool to predict positive blood cultures. The potential applicability of these findings could enhance clinical practice in terms of the accuracy and promptness of sepsis diagnosis in the ED, improving patient outcomes through timely and appropriate treatment.

Single-cell RNA sequencing and transcriptomic analysis reveal key genes and regulatory mechanisms in sepsis

The pathogenesis of sepsis, with a high mortality rate and often poor prognosis, has not been fully elucidated. Therefore, an in-depth study on the pathogenesis of sepsis at the molecular level is essential to identify key sepsis-related genes. The aim of this study was to explore the key genes and potential molecular mechanisms of sepsis using a bioinformatics approach. In addition, key genes with miRNA network correlation analysis and immune infiltration correlation analysis were investigated. The scRNA dataset (GSE167363) and RNA-seq dataset (GSE65682, GSE134347) from GEO database were used for screening out differentially expressed genes using single-cell sequencing and transcriptome sequencing. The analysis of immune infiltration was evaluated by the CIBERSORT method. Key genes and possible mechanisms were identified by WGCNA analysis, GSVA analysis, GSEA enrichment analysis and regulatory network analysis, and miRNA networks associated with key genes were constructed. Nine key genes associated with the development of sepsis, namely IL7R, CD3D, IL32, GPR183, HLA-DPB1, CD81, PEBP1, NCL, and ETS1 were screened, and the specific signaling mechanisms associated with the key genes causing sepsis were predicted. Immune profiling showed immune heterogeneity between control and sepsis samples. A regulatory network of 82 miRNAs, 266 pairs of mRNA-miRNA relationship pairs was also constructed. These nine key genes have the potential to become biomarkers for the diagnosis of sepsis and provide new targets and research directions for the treatment of sepsis.

Shadows and lights in sepsis immunotherapy

INTRODUCTION

Sepsis remains a major global public health challenge. The host's response in sepsis involves both an exaggerated inflammatory reaction and immunosuppressive mechanisms. A better understanding of this response has shed light on the failure of anti-inflammatory therapies administered under the 'one size fits all' approach during the last decades.

AREAS COVERED

To date, patients' management has moved toward a comprehensive precision medicine approach that aims to personalize immunotherapy, whether anti-inflammatory or immunostimulatory. Large Prospective interventional randomized controlled trials validating this approach are about to start. A crucial prerequisite for these studies is to stratify patients based on biomarkers that will help defining the patients' immuno-inflammatory trajectory.

EXPERT OPINION

Some biomarkers are already available in routine clinical care, while improvements are anticipated through the standardized use of transcriptomics and other multi-omics technologies in this field. With these precautions in mind, it is reasonable to anticipate improvement in outcomes in sepsis.

A New Easy-to-Perform Flow Cytometry Assay for Determining Bacterial- and Viral-Infection-Induced Polymorphonuclear Neutrophil and Monocyte Membrane Marker Modulation in Febrile Patients

We developed a flow cytometry (FC) assay enabling the rapid and accurate identification of bacterial and viral infections using whole blood samples. The streamlined flow cytometry assay is designed to be user-friendly, making it accessible even for operators with limited experience in FC techniques. The key components of the assay focus on the expression levels of specific surface markers-CD64 on polymorphonuclear neutrophils (PMN) as a marker for bacterial infection, and CD169 on monocytes (MO) for viral infection. The strong performance indicated by an area under the receiver operating characteristic (ROC) curve of 0.94 for both PMN CD64 positive predictive value (PPV) 97.96% and negative predictive value (NPV) 76.67%, and MO CD169 PPV 82.6% and NPV 86.9%, highlight the assay's robustness in differentiating between bacterial and viral infections accurately. The FC assay includes the assessment of immune system status through HLA-DR and IL-1R2 modulation in MO, providing a useful insight into the patients' immune response. The significant increase in the frequency of MO exhibiting reduced HLA-DR expression and elevated IL-1R2 levels in infected patients (compared to healthy controls) underscores the potential of these markers as indicators of infection severity. Although the overall correlation between HLA-DR and IL-1R2 expression levels was not significant across all patients, there was a trend in patients with more severe disease suggesting that these markers may have the potential to assist in stratifying patient risk. The present FC assay has the potential to become routine in the clinical microbiology laboratory community and to be helpful in guiding clinical decision making.

FOXO1-mediated autophagy regulation by miR-223 in sepsis-induced immunosuppression

Introduction

Immunosuppression is the main cause of the high mortality rate in patients with sepsis. The decrease in the number and dysfunction of CD4+ T lymphocytes is crucial to the immunosuppressed state of sepsis, in turn affecting the development and prognosis of sepsis. Autophagy has been shown to play an important role in the immune imbalance exhibited during sepsis.

Methods

In this study, we modulate the expression of miR-223 in CD4+ T lymphocytes, via the transfection of a mimic or an inhibitor of miR-223 to establish cell models of miR-223 overexpression and knockdown, respectively. Levels of autophagy were monitored using a double-labeled lentivirus (mRFP-GFP-LC3) and electron microscopy, and western blot analysis was used to estimate the levels of autophagy-related proteins and FOXO1 in the two cell models after co-treatment with lipopolysaccharide (LPS) and siRNA against FOXO1.

Results

We found that when the expression of miR-223 increased, FOXO1 expression decreased and autophagy decreased; whereas, when FOXO1 expression was inhibited, autophagy decreased significantly in different cell models after LPS induction.

Conclusion

Thus, this study proved that miR-223 participate in the regulation of LPS-induced autophagy via the regulation of FOXO1 expression in CD4+ T lymphocytes which shed a new light for the diagnosis and treatment of sepsis.

Temperature trajectories and mortality in hypothermic sepsis patients

OBJECTIVES

Hypothermia is associated with poor outcomes in sepsis patients, and hypothermic sepsis patients exhibit temperature alterations during initial treatment. The objective of this study was to classify hypothermic sepsis patients based on body temperature trajectories and investigate the associations of these patients with 28-day mortality.

METHODS

This was a retrospective analysis of prospectively collected data from adult sepsis or septic shock patients who visited three emergency departments between August 2014 and December 2019. Hypothermic sepsis was defined as an initial body temperature <36 °C. delta temperature was calculated by subtracting the 0 h body temperature from the 6 h body temperature. We divided the patients into three groups according to delta temperature: Group A (delta temperature ≤ 0), Group B (0 < delta temperature ≤ 1) and Group C (delta temperature > 1). The primary outcome was 28-day mortality, and a multivariable Cox proportional hazards regression model was generated.

RESULTS

Among 7344 patients with sepsis or septic shock, 325 hypothermic patients were included in the analysis, and the overall mortality rate was 36%. While initial body temperature was not different between survivors and nonsurvivors, survivors exhibited a higher body temperature at 6 h. The 28-day mortality rates for Groups A, B and C were 53.1%, 36.0%, and 30.0%, respectively, and Group A had significantly higher mortality than Group C did (p < 0.05). Group C demonstrated a 44.2% decrease in 28-day mortality compared to Group A (adjusted hazard ratio of 0.558; 95% confidence interval of 0.330-0.941).

CONCLUSIONS

In hypothermic sepsis patients, an increase of 1 °C or more in body temperature after the initial 6 h is associated with a reduced risk of 28-day mortality.

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.

The Role of Serum Albumin and Secretory Phospholipase A2 in Sepsis

Sepsis is caused by a dysregulated host response to an infection that leads to cascading cell death and eventually organ failure. In this study, the role of inflammatory response serum secretory phospholipase A2 (sPLA2) and albumin in sepsis was investigated by determining the activities of the two proteins in serial serum samples collected on different days from patients with sepsis after enrollment in the permissive underfeeding versus standard enteral feeding protocols in an intensive care unit. Serum sPLA2 and albumin showed an inverse relationship with increasing sPLA2 activity and decreasing albumin membrane-binding activity in patients with evolving complications of sepsis. The activities of sPLA2 and albumin returned to normal values more rapidly in the permissive underfeeding group than in the standard enteral feeding group. The inverse sPLA2-albumin activity relationship suggests a complex interplay between these two proteins and a regulatory mechanism underlying cell membrane phospholipid homeostasis in sepsis. The decreased albumin-membrane binding activity in patients' serum was due to its fatty acid-binding sites occupied by pre-bound fatty acids that might alter albumin's structure, binding capacities, and essential functions. The sPLA2-albumin dual serum assays may be useful in determining whether nutritional intervention effectively supports the more rapid recovery of appropriate immune responses in critically ill patients with sepsis.

Modeling "Two-Hit" Severe Pneumonia in Mice: Pathological Characteristics and Mechanistic Studies

Severe pneumonia is one of the most common critical diseases in clinical practice. Existing models for severe pneumonia have limitations, leading to limited clinical translation. In this study, a two-hit severe pneumonia mouse model was established by inducing primary pneumonia through intratracheal instillation of 800 μg lipopolysaccharide (LPS), followed by intraperitoneal injection of 10 mg/kg LPS. The effectiveness of various inflammatory indicators and the lung tissue damage during the time course of this model were confirmed and evaluated. At 3 h post two-hit, the IL-6, TNF-α levels in peripheral blood and bronchoalveolar lavage fluid (BALF), and the white blood cells, neutrophils, and lymphocytes in BALF notably exhibited the most pronounced elevation. At 12 h post two-hit, the white blood cells and neutrophils in peripheral blood significantly increased, accompanied by notable alterations in splenic immune cells and worsened pulmonary histopathological damage. Transcriptomics of lung tissue, microbiota analysis of lung and gut, as well as plasma metabolomics analyses further indicated changes in transcriptional profiles, microbial composition, and metabolites due to the two-hit modeling. These results validate that the two-hit model mimics the clinical presentation of severe pneumonia and serves as a robust experimental tool for studying the pathogenesis of severe pneumonia and developing and assessing treatment strategies.

Multidisciplinary integration and fusion based on critical care medicine and immunology: History, current status, and prospects

Critical care medicine focuses on understanding the pathophysiological mechanisms and treatment approaches for life-threatening conditions, including sepsis, severe trauma/burns, hemorrhagic shock, heatstroke, and acute pancreatitis, all of which have high incidence rates. These conditions are primarily characterized by acute multi-organ dysfunction, with sudden onset, severe illness, and high mortality rates. Additionally, critical care treatment demands substantial medical resources, imposing significant economic burdens on patients' families and society. In recent years, critical care medicine has achieved notable progress, especially in multidisciplinary integration with immunology-based fields. Collaboration across disciplines has not only accelerated advancements in critical care but also propelled the rapid development of modern immunology. This paper provides an overview and assessment of the cross-disciplinary fusion between critical care medicine and immunology, exploring how these fields related extensions mutually enhance each other. It further analyzes China's potential to become a global leader in this area within the next 5 to 10 years.

Current perspectives in the management of sepsis and septic shock

Within patients with sepsis, there exists significant heterogeneity, and while all patients should receive conventional therapy, there are subgroups of patients who may benefit from specific therapies, often referred to as rescue therapies. Therefore, the identification of these specific patient subgroups is crucial and lays the groundwork for the application of precision medicine based on the development of targeted interventions. Over the years, efforts have been made to categorize sepsis into different subtypes based on clinical characteristics, biomarkers, or underlying mechanisms. For example, sepsis can be stratified into different phenotypes based on the predominant dysregulated host response. These phenotypes can range from hyperinflammatory states to immunosuppressive states and even mixed phenotypes. Each phenotype may require different therapeutic approaches to improve patient outcomes. Rescue strategies for septic shock may encompass various interventions, such as immunomodulatory therapies, extracorporeal support (e.g., ECMO), or therapies targeted at specific molecular or cellular pathways involved in the pathophysiology of sepsis. In recent years, there has been growing interest in precision medicine approaches to sepsis and phenotype identification. Precision medicine aims to tailor treatments to each individual patient based on their unique characteristics and disease mechanisms.