Characterization of Early Peripheral Immune Responses in Patients with Sepsis and Septic Shock

EARLY ANALYSIS OF ENDOTHELIAL MARKERS TO PREDICT SEPSIS IN THE EMERGENCY DEPARTMENT

ABSTRACT

Background: Acute infections and sepsis are a leading cause of death. These patients are primarily encountered at the emergency department (ED), where early assessment for sepsis is necessary to improve outcome. In sepsis, the inflammatory response causes several characteristic pathophysiological changes, including a dysregulated and generalized activation of the endothelium. This study aimed to analyze endothelial markers released to the blood as diagnostic biomarkers for acute infection and sepsis in the ED, as smaller studies have previously shown promising results in other settings. Methods : Serum samples from n = 312 adult patients with suspected acute infections at presentation to the ED were utilized. Patients' courses of disease and outcomes were assessed by clinical adjudication. E-selectin, P-selectin, ICAM-1, and VCAM-1 were measured by ELISAs. The accuracy of each marker for predicting bacterial infection, sepsis, and in-hospital mortality was evaluated. Results : For sepsis, E-selectin and ICAM-1 both showed an area under the receiver operating characteristic (AUROC) of 0.62, lower than procalcitonin with 0.77 (both P < 0.01) and lactate with 0.73 ( P = 0.030 and 0.046, respectively), but similar to CRP with 0.60 ( P = 0.758 and 0.876, respectively). For 28-day in-hospital mortality among patients with infection, ICAM-1 performed best with an AUROC of 0.75. Conclusions : Despite promising results in small studies and specific cohorts, particularly in intensive care units, this large-scale evaluation of four endothelial biomarkers highlights their limited diagnostic utility in a broader inclusion setup design at the earliest possible time point of evaluation.

The significance of long chain non-coding RNA signature genes in the diagnosis and management of sepsis patients, and the development of a prediction model

Background

Sepsis is a life-threatening organ dysfunction condition produced by dysregulation of the host response to infection. It is now characterized by a high clinical morbidity and mortality rate, endangering patients' lives and health. The purpose of this study was to determine the value of Long chain non-coding RNA (LncRNA) RP3_508I15.21, RP11_295G20.2, and LDLRAD4_AS1 in the diagnosis of adult sepsis patients and to develop a Nomogram prediction model.

Methods

We screened adult sepsis microarray datasets GSE57065 and GSE95233 from the GEO database and performed differentially expressed genes (DEGs), weighted gene co-expression network analysis (WGCNA), and machine learning methods to find the genes by random forest (Random Forest), least absolute shrinkage and selection operator (LASSO), and support vector machine (SVM), respectively, with GSE95233 as the training set and GSE57065 as the validation set. Differentially expressed genes (DEGs), weighted gene co-expression network analysis (WGCNA), boxplot statistical analysis, and ROC analysis by Random Forest, Least Absolute Shrinkage and Selection Operator (LASSO), and Support Vector Machine (SVM) machine learning methods were used to identify characteristic genes and build the Nomogram Prediction model.

Results

GSE95233 yielded a total of 1069 genes, 102 of which were sepsis-related and 22 of which were non-sepsis controls. GSE57065 yielded a total of 899 genes, with 467 up-regulated and 432 down-regulated, including 82 sepsis-related genes and 25 non-sepsis control genes. WGCNA analysis excluded outlier samples, leaving 2,029 genes for relationship analysis between sepsis- and non-sepsis patient-associated LncRNA network representation modules, as well as Wein plots of differential genes versus genes in key modules of weighted co-expression network analysis to analyze gene intersections. Machine Learning found the sepsis-related characteristic LncRNAs RP3-508I15.21, RP11-295G20.2, LDLRAD4-AS1, and CTD-2542L18.1. The datasets GSE95233 and GSE57065 were analyzed using Boxplot against the screened genes listed above, respectively. The p-value between the sepsis and non-sepsis groups was less than 0.05, indicating that anomalies were statistically significant. CTD-2542L18.1 in dataset GSE57065 had an AUC value of 0.638, which was less than 0.7 and did not indicate diagnostic significance, but RP3-508I15.21, RP11-295G20.2, and LDLRAD4-AS1 had AUC values more than 0.7 after ROC analysis. All four sepsis-associated LncRNA ROC analyses in dataset GSE95233 exhibited AUC values more than 0.7, indicating diagnostic significance.

Conclusion

LncRNAs RP3_508I15.21, RP11_295G20.2, and LDLRAD4_AS1 have some utility in the diagnosis and treatment of adult sepsis patients, as well as some reference importance in guiding the diagnosis and treatment of clinical sepsis.

ICAM1 and VCAM1 are associated with outcome in patients with sepsis: A systematic review and meta-analysis

Background

Endothelial cell dysfunction and microcirculatory disturbances play crucial roles in the pathogenesis of sepsis. This systematic review and meta-analysis explored the relationship of the plasma levels of the key endothelial proteins intercellular adhesion molecule 1 (ICAM1) and vascular cell adhesion molecule 1 (VCAM1) with clinical outcomes in patients with sepsis.

Methods

MEDLINE and EMBASE were searched through November 28, 2023. ICAM1 and VCAM1 levels and patient outcomes were evaluated. The primary outcome was the relationship of sepsis with ICAM1 or VCAM1. The secondary outcomes were the relationships of septic shock and multiple-organ dysfunction syndrome (MODS) with ICAM1 and VCAM1. Variables were compared using standardized mean differences (SMDs) with 95 % confidence intervals (CIs).

Results

Forty-one studies were included. ICAM1 (SMD = 1.12, 95 % CI = 0.67, 1.57; P < 0.00001) and VCAM1 (SMD = 0.65; 95 % CI = 0.17, 1.13; P = 0.008) were associated with sepsis. Similarly, both ICAM1 (SMD = 2.30; 95 % CI = 1.30, 3.31; P < 0.00001) and VCAM1 (SMD = 0.93; 95 % CI = 0.27, 1.59; P = 0.006) were associated with MODS. ICAM1 was associated with septic shock (SMD = 1.93; 95 % CI = 0.55, 3.30; P = 0.006), overall mortality (SMD = -1.18; 95 % CI = -1.76, -0.61; P < 0.0001), and sepsis-related mortality (SMD = -0.64; 95 % CI = -0.88, -0.39; P < 0.00001). VCAM1 was associated with overall mortality (SMD = -0.71; 95 % CI = -1.02, -0.40; P < 0.00001), sepsis-related mortality (SMD = -0.62; 95 % CI = -1.14, -0.10; P = 0.02), and MODS-related mortality (SMD = -0.55; 95 % CI = -0.89, -0.21; P = 0.002).

Conclusion

Elevated plasma ICAM1 and VCAM1 levels could increase the risks of sepsis, septic shock, MODS, and mortality.

The Modulation of Septic Shock: A Proteomic Approach

Sepsis poses a significant challenge due its lethality, involving multiple organ dysfunction and impaired immune responses. Among several factors affecting sepsis, monocytes play a crucial role; however, their phenotype, proteomic profile, and function in septic shock remain unclear. Our aim was to fully characterize the subpopulations and proteomic profiles of monocytes seen in septic shock cases and discuss their possible impact on the disease. Peripheral blood monocyte subpopulations were phenotype based on CD14/CD16 expression by flow cytometry, and proteins were extracted from the monocytes of individuals with septic shock and healthy controls to identify changes in the global protein expression in these cells. Analysis using 2D-nanoUPLC-UDMSE identified 67 differentially expressed proteins in shock patients compared to controls, in which 44 were upregulated and 23 downregulated. These proteins are involved in monocyte reprogramming, immune dysfunction, severe hypotension, hypo-responsiveness to vasoconstrictors, vasodilation, endothelial dysfunction, vascular injury, and blood clotting, elucidating the disease severity and therapeutic challenges of septic shock. This study identified critical biological targets in monocytes that could serve as potential biomarkers for the diagnosis, prognosis, and treatment of septic shock, providing new insights into the pathophysiology of the disease.

Effects of Oxiris® Therapy on Cytokine Elimination after a LPS Infusion-An Experimental Animal Study

The clinical effectiveness of Oxiris®, particularly in reducing cytokines, remains uncertain due to the limited data provided. This study explored and analyzed the application value of Oxiris® endotoxin adsorption technology in a large animal model. Pigs received an intravenous LPS infusion. Six animals were treated 2 h after the infusion with an Oxiris® hemadsorption using a pumpless extracorporeal technique for 6 h. Five animals served as controls. Cardiocirculatory parameters, hyperspectral analysis, and a panel of cytokines were measured. The lipopolysaccharide infusion induced sepsis-like inflammation with tachycardia, elevated pulmonary pressure, elevated lactate level, as well as elevated pro-inflammatory cytokines like interferon (IFN)-γ, interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-12 and tumor necrosis factor alpha (TNF-α). In addition, increases of anti-inflammatory cytokines like IL-1ra and IL-10 were found. After 3 and 6 h in both groups, pro-inflammatory cytokines were significantly reduced. No differences between the intervention and the control group could be detected after 3 and 6 h for IL-1β, IL-2, IL-6, IL-8, IL-12 and TNF-α, suggesting no effect of the Oxiris® filter on the elimination of elevated cytokines with a pumpless extracorporeal hemadsorption technique. The presented large animal model may be a promising option for studying the effects of hemadsorption techniques.

Lipid Fraction from Agaricus brasiliensis as a Potential Therapeutic Agent for Lethal Sepsis in Mice

Sepsis is a potentially fatal clinical condition that results from an immune imbalance in the host during an infection. It presents systemic alterations due to excessive activation of pro-inflammatory mediators that contribute to inflammation, formation of reactive species, and tissue damage. Anti-inflammatory mediators are then extensively activated to regulate this process, leading to immune exhaustion and, consequently, immunosuppression of the host. Considering the biological activities of the nutraceutical Agaricus brasiliensis (A. brasiliensis), such as immunomodulatory, antioxidant, and antitumor activities, the present study investigated the therapeutic potential of the lipid fraction of A. brasiliensis (LF) in a model of lethal sepsis in mice (Mus musculus), induced by cecal ligation and perforation (CLP). The results showed that treatment of septic animals with LF or LF associated with ertapenem (LF-Erta) reduced systemic inflammation, promoting improvement in clinical parameters and increased survival. The data show a reduction in pro-inflammatory and oxidative stress markers, regulation of the anti-inflammatory response and oxidizing agents, and increased bacterial clearance in the peritoneal cavity and liver. Thus, it can be concluded that LF as a treatment, and in conjunction with antibiotic therapy, has shown promising effects as a hepatoprotective, antioxidant, antimicrobial, and immunomodulatory agent.

Construction and validation of a nomogram prediction model for the progression to septic shock in elderly patients with urosepsis

Background

Septic shock is a clinical syndrome characterized by the progression of sepsis to a severe stage. Elderly patients with urosepsis in the intensive care unit (ICU) are more likely to progress to septic shock. This study aimed to establish and validate a nomogram model for predicting the risk of progression to septic shock in elderly patients with urosepsis.

Methods

We extracted data from the Medical Information Mart for Intensive Care (MIMIC-IV) and the eICU Collaborative Research Database (eICU-CRD). The MIMIC-IV dataset was split into a training set for model development and an internal validation set to assess model performance. Further external validation was performed using a distinct dataset sourced from the eICU-CRD. Predictors were screened using least absolute shrinkage and selection operator (LASSO) regression and multivariable logistic regression analyses. The evaluation of model performance included discrimination, calibration, and clinical usefulness.

Results

The study demonstrated that the Glasgow Coma Scale (GCS), white blood count (WBC), platelet, blood urea nitrogen (BUN), calcium, albumin, congestive heart failure (CHF), and invasive ventilation were closely associated with septic shock in the training cohort. Nomogram prediction, utilizing eight parameters, demonstrated strong predictive accuracy with area under the curve (AUC) values of 0.809 (95 % CI 0.786-0.834), 0.794 (95 % CI 0.756-0.831), and 0.723 (95 % CI 0.647-0.801) in the training, internal validation, and external validation sets, respectively. Additionally, the nomogram demonstrated a promising calibration performance and significant clinical usefulness in both the training and validation sets.

Conclusion

The constructed nomogram is a reliable and practical tool for predicting the risk of progression to septic shock in elderly patients with urosepsis. Its implementation in clinical practice may enhance the early identification of high-risk patients, facilitate timely and targeted interventions to mitigate the risk of septic shock, and improve patient outcomes.

Commonly disrupted pathways in brain and kidney in a pig model of systemic endotoxemia

Sepsis is a life-threatening state that arises due to a hyperactive inflammatory response stimulated by infection and rarely other insults (e.g., non-infections tissue injury). Although changes in several proinflammatory cytokines and signals are documented in humans and small animal models, far less is known about responses within affected tissues of large animal models. We sought to understand the changes that occur during the initial stages of inflammation by administering intravenous lipopolysaccharide (LPS) to Yorkshire pigs and assessing transcriptomic alterations in the brain, kidney, and whole blood. Robust transcriptional alterations were found in the brain, with upregulated responses enriched in inflammatory pathways and downregulated responses enriched in tight junction and blood vessel functions. Comparison of the inflammatory response in the pig brain to a similar mouse model demonstrated some overlapping changes but also numerous differences, including oppositely dysregulated genes between species. Substantial changes also occurred in the kidneys following LPS with several enriched upregulated pathways (cytokines, lipids, unfolded protein response, etc.) and downregulated gene sets (tube morphogenesis, glomerulus development, GTPase signal transduction, etc.). We also found significant dysregulation of genes in whole blood that fell into several gene ontology categories (cytokines, cell cycle, neutrophil degranulation, etc.). We observed a strong correlation between the brain and kidney responses, with significantly shared upregulated pathways (cytokine signaling, cell death, VEGFA pathways) and downregulated pathways (vasculature and RAC1 GTPases). In summary, we have identified a core set of shared genes and pathways in a pig model of systemic inflammation.

Alterations in leukocyte DNA methylome are associated to immunosuppression in severe clinical phenotypes of septic patients

Introduction

Sepsis patients experience a complex interplay of host pro- and anti-inflammatory processes which compromise the clinical outcome. Despite considering the latest clinical and scientific research, our comprehension of the immunosuppressive events in septic episodes remains incomplete. Additionally, a lack of data exists regarding the role of epigenetics in modulating immunosuppression, subsequently impacting patient survival.

Methods

To advance the current understanding of the mechanisms underlying immunosuppression, in this study we explored the dynamics of DNA methylation using the Infinium Methylation EPIC v1.0 BeadChip Kit in leukocytes from patients suffering from sepsis, septic shock, and critically ill patients as controls, within the first 24 h after admission in the Intensive Care Unit of a tertiary hospital.

Results and discussion

Employing two distinct analysis approaches (DMRcate and mCSEA) in comparing septic shock and critically ill patients, we identified 1,256 differentially methylated regions (DMRs) intricately linked to critical immune system pathways. The examination of the top 100 differentially methylated positions (DMPs) between septic shock and critically ill patients facilitated a clear demarcation among the three patient groups. Notably, the top 6,657 DMPs exhibited associations with organ dysfunction and lactate levels. Among the individual genes displaying significant differential methylation, IL10, TREM1, IL1B, and TNFAIP8 emerged with the most pronounced methylation alterations across the diverse patient groups when subjected to DNA bisulfite pyrosequencing analysis. These findings underscore the dynamic nature of DNA methylation profiles, highlighting the most pronounced alterations in patients with septic shock, and revealing their close association with the disease.

Identification of Potential Biomarkers of Septic Shock Based on Pathway and Transcriptome Analyses of Immune-Related Genes

Immunoregulation is crucial to septic shock (SS) but has not been clearly explained. Our aim was to explore potential biomarkers for SS by pathway and transcriptional analyses of immune-related genes to improve early detection. GSE57065 and GSE95233 microarray data were used to screen differentially expressed genes (DEGs) in SS. Gene Ontology and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analyses of DEGs were performed, and correlations between immune cell and pathway enrichment scores were analyzed. The predictive value of candidate genes was evaluated by receiver operating characteristic (ROC) curves. GSE66099, GSE4607, and GSE13904 datasets were used for external validation. Blood samples from six patients and six controls were collected for validation by qRT-PCR and western blotting. In total, 550 DEGs in SS were identified; these genes were involved in the immune response, inflammation, and infection. Immune-related pathways and levels of infiltration of CD4 + TCM, CD8 + T cells, and preadipocytes differed between SS cases and controls. Seventeen genes were identified as potential biomarkers of SS (areas under ROC curves >0.9). The downregulation of CD8A, CD247, CD3G, LCK, and HLA-DRA in SS was experimentally confirmed. We identified several immune-related biomarkers in SS that may improve early identification of disease risk.

Validation of circulating histone detection by mass spectrometry for early diagnosis, prognosis, and management of critically ill septic patients

BACKGROUND

As leading contributors to worldwide morbidity and mortality, sepsis and septic shock are considered a major global health concern. Proactive biomarker identification in patients with sepsis suspicion at any time remains a daunting challenge for hospitals. Despite great progress in the understanding of clinical and molecular aspects of sepsis, its definition, diagnosis, and treatment remain challenging, highlighting a need for new biomarkers with potential to improve critically ill patient management. In this study we validate a quantitative mass spectrometry method to measure circulating histone levels in plasma samples for the diagnosis and prognosis of sepsis and septic shock patients.

METHODS

We used the mass spectrometry technique of multiple reaction monitoring to quantify circulating histones H2B and H3 in plasma from a monocenter cohort of critically ill patients admitted to an Intensive Care Unit (ICU) and evaluated its performance for the diagnosis and prognosis of sepsis and septic shock (SS).

RESULTS

Our results highlight the potential of our test for early diagnosis of sepsis and SS. H2B levels above 121.40 ng/mL (IQR 446.70) were indicative of SS. The value of blood circulating histones to identify a subset of SS patients in a more severe stage with associated organ failure was also tested, revealing circulating levels of histones H2B above 435.61 ng/ml (IQR 2407.10) and H3 above 300.61 ng/ml (IQR 912.77) in septic shock patients with organ failure requiring invasive organ support therapies. Importantly, we found levels of H2B and H3 above 400.44 ng/mL (IQR 1335.54) and 258.25 (IQR 470.44), respectively in those patients who debut with disseminated intravascular coagulation (DIC). Finally, a receiver operating characteristic curve (ROC curve) demonstrated the prognostic value of circulating histone H3 to predict fatal outcomes and found for histone H3 an area under the curve (AUC) of 0.720 (CI 0.546-0.895) p < 0.016 on a positive test cut-off point at 486.84 ng/mL, showing a sensitivity of 66.7% and specificity of 73.9%.

CONCLUSIONS

Circulating histones analyzed by MS can be used to diagnose SS and identify patients at high risk of suffering DIC and fatal outcome.

Histone Citrullination Mediates a Protective Role in Endothelium and Modulates Inflammation

NETosis is a key host immune process against a pathogenic infection during innate immune activation, consisting of a neutrophil "explosion" and, consequently, NET formation, containing mainly DNA, histones, and other nuclear proteins. During sepsis, an exacerbated immune host response to an infection occurs, activating the innate immunity and NETosis events, which requires histone H3 citrullination. Our group compared the circulating histone levels with those citrullinated H3 levels in plasma samples of septic patients. In addition, we demonstrated that citrullinated histones were less cytotoxic for endothelial cells than histones without this post-translational modification. Citrullinated histones did not affect cell viability and did not activate oxidative stress. Nevertheless, citrullinated histones induced an inflammatory response, as well as regulatory endothelial mechanisms. Furthermore, septic patients showed elevated levels of circulating citrullinated histone H3, indicating that the histone citrullination is produced during the first stages of sepsis, probably due to the NETosis process.

The immunomodulatory function of adenosine in sepsis

Sepsis is an unsolved clinical condition with a substantial mortality rate in the hospital. Despite decades of research, no effective treatments for sepsis exists. The role of adenosine in the pathogenesis of sepsis is discussed in this paper. Adenosine is an essential endogenous molecule that activates the A1, A2a, A2b, and A3 adenosine receptors to regulate tissue function. These receptors are found on a wide range of immune cells and bind adenosine, which helps to control the immune response to inflammation. The adenosine receptors have many regulatory activities that determine the onset and progression of the disease, which have been discovered via the use of animal models. A greater understanding of the role of adenosine in modulating the immune system has sparked hope that an adenosine receptor-targeted treatment may be used one day to treat sepsis.