The pathophysiology of sepsis-2021 update: Part 1, immunology and coagulopathy leading to endothelial injury

Predicting survival in sepsis: The prognostic value of NLR and BAR ratios

BACKGROUND

Due to the high-risk nature of sepsis, emergency departments urgently need a simple evaluation method to assess the degree of inflammation and prognosis in sepsis patients, providing a reference for diagnosis and treatment.

OBJECTIVE

To investigate the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) combined with the blood urea nitrogen-to-serum albumin ratio (BAR) in sepsis.

METHODS

A total of 377 sepsis patients admitted to Lishui People's Hospital from June 2022 to June 2023 were selected as the study subjects. Based on their prognosis, they were divided into a survival group (255 cases) and a death group (82 cases). The clinical data of the two groups were compared. Multivariate logistic analysis was used to identify factors influencing sepsis prognosis, and ROC curve analysis was used to assess the predictive efficacy of NLR, BAR, and their combination.

RESULTS

Compared with survivors, non-survivors had higher NLR and BAR, with statistically significant differences (p< 0.05). After adjusting for confounding factors, NLR (OR = 1.052) and BAR (OR = 1.095) were found to be independent prognostic factors for sepsis patients (both p< 0.05). The AUC of NLR combined with BAR was 0.798 (95% CI 0.745-0.850, p< 0.05), higher than the AUC of NLR alone (0.776) and BAR alone (0.701).

CONCLUSIONS

The combination of NLR and BAR has a high predictive value for the prognosis of sepsis patients. Its simple calculation makes it particularly suitable for use in emergency departments.

A retrospective Cohort study on the effect of the LOw-molecular weighT heparin (LMWH) nadroparin dose on anti-XA levels in a mixed medical-surgical ICU population: CLOT-Xa

PURPOSE

Low-molecular-weight heparins (LMWHs) are widely used for prevention and treatment of venous thromboembolism (VTE) in critically ill patients. The objective of this study was to assess the dose-response relationship between nadroparin dose and anti-Xa activity in ICU patients.

MATERIALS AND METHODS

Critically ill adult patients who were admitted to the ICU, and received at least three subcutaneous injections of nadroparin were included. The dose-effect relationship between nadroparin dose and anti-Xa level was analysed through a mixed-effects logistic regression model.

RESULTS

In total, 327 ICU patients were included. Median anti-Xa levels ranged from <0.1 IU/mL after nadroparin 0-37 IU/kg/day to 0.6 IU/mL after nadroparin >85 IU/kg/day (p < 0.01). Among all 1520 anti-Xa measurements, 859 (57 %) measurements were in the desired anti-Xa range. The best adequacy of anti-Xa levels was observed in nadroparin doses of 38-85 IU/kg (73 %). No differences in the odds of bleeding events or VTE between different anti-Xa levels were found.

CONCLUSIONS

We found a clear dose-response relationship between nadroparin dose and anti-Xa levels. Increasing nadroparin doses led to more adequate anti-Xa levels without a change in the occurrence of VTE or major bleeding events, suggesting that LMWH therapy can be successfully and safely personalized using anti-Xa guided dosing.

Potential mechanism of CARD16 protein action and susceptibility to sepsis in the elderly infected population: Through transcriptome analysis of blood

As global aging accelerates, the super-elderly population is at higher risk of infectious diseases, especially sepsis, a condition that may be associated with declining immune system function and abnormal inflammatory responses. The aim of this study was to investigate the role of CARD16 protein in sepsis susceptibility in the elderly population and its potential mechanism, and to reveal the expression characteristics of CARD16-related genes through blood transcriptomic analysis. Transcriptome sequencing was conducted on peripheral blood samples obtained from patients suffering from senile sepsis, along with samples from a healthy elderly control group. To examine the differences in gene expression, bioinformatics techniques were employed to compare the expression levels of CARD16-related genes between the two groups. Additionally, a comprehensive analysis was performed on the downstream inflammatory pathways and cytokines that are regulated by CARD16.The findings from the transcriptome analysis indicated that the expression of CARD16 was markedly upregulated in the cohort of patients experiencing hypersenile sepsis. This upregulation was associated with an increase in a variety of pro-inflammatory factors. Further network analysis suggested that CARD16 may potentiate the inflammatory response by modulating the NF-κB signaling pathway, which could consequently heighten the patients' vulnerability to sepsis.In comparison to the healthy elderly control group, the levels of anti-inflammatory genes in the super-elderly cohort were found to be significantly diminished. This observation points to a notable imbalance in immune regulation, further emphasizing the altered immune response in individuals with senile sepsis.

Sepsis-Induced Coagulopathy Score is Associated with an Increased Risk of New-Onset Atrial Fibrillation in Septic Patients: A Two-Centered Retrospective Study

Purpose

New-onset atrial fibrillation (NOAF) and sepsis-induced coagulopathy (SIC) are severe complications in septic patients. However, the relationship between NOAF and SIC score has not been clearly defined. This study aims to investigate the association between SIC score and NOAF, as well as their effect on mortality in sepsis.

Patients and Methods

This study was a two-center retrospective analysis. Medical data were collected from patients diagnosed with sepsis. The patients were divided into NOAF and non-NOAF groups, and the SIC score was calculated for each group. Univariable and multivariable logistic regression analyses were performed to explore the relationship between the SIC score and NOAF, as well as their effects on mortality. The Kaplan-Meier curve was used to assess the survival rate.

Results

A total of 2,280 septic patients were included, with 132 (5.7%) suffering from NOAF. Multivariable logistic regression analyses indicated that age, gender, the Acute Physiology and Chronic Health Evaluation II score (APACHE II), heart rate, renal failure, stroke, chronic obstructive pulmonary disease (COPD), and the SIC score were independent risk factors for NOAF in sepsis. Moreover, NOAF was associated with an increased risk of in-hospital mortality, 28-day mortality, and 90-day mortality. These results were consistent across subgroup analyses.

Conclusion

The SIC score was an independent risk factor for NOAF in septic patients, and NOAF was an independent risk factor for predicting mortality.

Fluid Resuscitation Dilemma in End-stage Renal Disease Patients Presenting with Sepsis: A Systematic Review and Meta-analysis

Background: This study aims to investigate the safety and efficacy of guideline-directed fluid resuscitation (GDFR) compared with conservative fluid management in end-stage renal disease (ESRD) patients with sepsis by evaluating 90-day mortality and intubation rate. Methods: Following PRISMA guidelines, a systematic review was conducted across multiple databases using specific keywords and controlled vocabulary. The search strategy, implemented until October 1, 2023, aimed to identify studies examining fluid resuscitation in ESRD patients with sepsis. The review process was streamlined using Covidence software. A fourth reviewer resolved discrepancies in study inclusion. A random-effects model with the generic Mantel-Haenszel method was preferred for integrating odds ratios (ORs). Sensitivity analysis and publication bias analysis were performed. Results: Of the 1274 identified studies, 10 were selected for inclusion, examining 1184 patients, 593 of whom received GDFR. Four studies were selected to investigate the intubation rate, including 304 patients. No significant mortality or intubation rate difference was spotted between both groups [OR = 1.23; confidence interval (CI) = 0.92-1.65; I2 = 0% and OR = 1.91; CI = 0.91-4.04]. In most studies, sensitivity analysis using the leave-one-out approach revealed higher mortality and intubation rates. The Egger test results indicated no statistically significant publication bias across the included studies. Conclusion: Our research contradicts the common assumption about the effectiveness of GDFR for sepsis patients with ESRD. It suggests that this approach, while not superior to the conservative strategy, may potentially be harmful.

Mangiferin attenuates lipopolysaccharide-induced neuronal injuries in primary cultured hippocampal neurons

Mangiferin, a naturally occurring potent glucosylxanthone, is mainly isolated from the Mangifera indica plant and shows potential pharmacological properties, including anti-bacterial, anti-inflammation, and antioxidant in sepsis-induced lung and kidney injury. However, there was a puzzle as to whether mangiferin had a protective effect on sepsis-associated encephalopathy. To answer this question, we established an in vitro cell model of sepsis-associated encephalopathy and investigated the neuroprotective effects of mangiferin in primary cultured hippocampal neurons challenged with lipopolysaccharide (LPS). Neurons treated with 20 μmol/L or 40 μmol/L mangiferin for 48 h can significantly reverse cell injuries induced by LPS treatment, including improved cell viability, decreased inflammatory cytokines secretion, relief of microtubule-associated light chain 3 expression levels and several autophagosomes, as well as attenuated cell apoptosis. Furthermore, mangiferin eliminated pathogenic proteins and elevated neuroprotective factors at both the mRNA and protein levels, showing strong neuroprotective effects of mangiferin, including anti-inflammatory, anti-autophagy, and anti-apoptotic effects on neurons in vitro.

Case report: Enhancing prognosis in severe COVID-19 through human herpes virus coinfection treatment strategies

Background

In the context of increasing reports of co-infection with coronavirus disease 2019 (COVID-19), particularly with human herpes viruses (HHVs), it is important to consider the appropriate treatment options for HHVs that have been reactivated by COVID-19.

Case presentation

This study presents two cases of severe COVID-19 with HHV co-infection. The first case involved a critically ill patient with COVID-19 co-infected with herpes simplex virus type 1, confirmed using metagenomic next-generation sequencing, and another patient with severe COVID-19 experiencing Epstein-Barr virus (EBV) reactivation, as evidenced by elevated EBV-DNA levels in the serum. Treatment included high-dose glucocorticoids and sivelestat sodium, with notable improvements observed after initiating ganciclovir anti-herpesvirus therapy.

Conclusion

This study underscores the significance of recognizing HHV co-infections in severe COVID-19 cases and highlights the potential of combining anti-HHV treatment, increased glucocorticoid dosages, and anti-cytokine storm therapy to enhance prognosis.

Bacterial lipopolysaccharide-induced endothelial activation and dysfunction: a new predictive and therapeutic paradigm for sepsis

BACKGROUND

Lipopolysaccharide, a highly potent endotoxin responsible for severe sepsis, is the major constituent of the outer membrane of gram-negative bacteria. Endothelial cells participate in both innate and adaptive immune responses as the first cell types to detect lipopolysaccharide or other foreign debris in the bloodstream. Endothelial cells are able to recognize the presence of LPS and recruit specific adaptor proteins to the membrane domains of TLR4, thereby initiating an intracellular signaling cascade. However, lipopolysaccharide binding to endothelial cells induces endothelial activation and even damage, manifested by the expression of proinflammatory cytokines and adhesion molecules that lead to sepsis.

MAIN FINDINGS

LPS is involved in both local and systemic inflammation, activating both innate and adaptive immunity. Translocation of lipopolysaccharide into the circulation causes endotoxemia. Endothelial dysfunction, including exaggerated inflammation, coagulopathy and vascular leakage, may play a central role in the dysregulated host response and pathogenesis of sepsis. By discussing the many strategies used to treat sepsis, this review attempts to provide an overview of how lipopolysaccharide induces the ever more complex syndrome of sepsis and the potential for the development of novel sepsis therapeutics.

CONCLUSIONS

To reduce patient morbidity and mortality, preservation of endothelial function would be central to the management of sepsis.

Ameliorating effects of berberine on sepsis-associated lung inflammation induced by lipopolysaccharide: molecular mechanisms and preclinical evidence

As a life-threatening disorder, sepsis-associated lung injury is a dysregulated inflammatory response to microbial infection, characterized by the infiltration of inflammatory cells into lung tissues and excessive production of pro-inflammatory mediators. Therefore, immunomodulatory/anti-inflammatory agents are a potential treatment for sepsis-associated lung injury. Berberine, one of the well-studied medicinal plant-derived compounds, has shown promising anti-inflammatory potential in inflammatory conditions, through modulating excessive immune responses induced by various immune cells. A systematic literature search in electronic databases indicated several publications that studied the effect of berberine on lipopolysaccharide (LPS)-induced sepsis in preclinical investigations. The current review article aims to provide evidence on the effects of berberine against LPS-induced acute lung injury (ALI), together with underlying molecular mechanisms. The findings reveal that berberine through inhibiting the excessive production of multiple pro-inflammatory cytokines, suppressing the infiltration of immune cells into lung tissues, as well as preventing pulmonary edema and coagulation, can relieve pulmonary histopathological changes from LPS-mediated inflammation, thereby attenuating sepsis-associated lung injury and lethality in the experimental models. In conclusion, berberine shows great potential as a preventing and therapeutic agent for sepsis-associated lung injury, however, further proof-of-concept studies and clinical investigations are warranted for translating these preclinical findings into clinical practices.

Septic shock in obstetrics: guidelines of the All-Russian public organization “Federation of Anesthesiologists and Reanimatologists”

The article reflects the main provisions of the clinical guidelines on septic shock in obstetrics, approved by the All-Russian public organization “Federation of Anesthesiologists-Resuscitators” in 2022. The relevance of the problem is associated with high mortality and morbidity rates from sepsis and septic shock in obstetrics. The main issues of etiology, pathogenesis, clinical picture, methods of laboratory and instrumental diagnostics, features of using the qSOFA, SOFA, MOEWS, SOS, MEWC, IMEWS scales for sepsis verification are consistently presented. The article presents the starting intensive therapy (the first 6–12 hours) of the treatment of septic shock in obstetrics, taking into account the characteristics of the pregnant woman's body. The strategy of prescribing vasopressors (norepinephrine, phenylephrine, epinephrine), inotropic drugs (dobutamine) is described, antibiotics and optimal antibiotic therapy regimens, features of infusion and adjuvant therapy are presented. The issues of surgical treatment of the focus of infection and indications for hysterectomy, as well as the organization of medical care and rehabilitation of patients with sepsis and septic shock were discussed. The basic principles of prevention of sepsis and septic shock in obstetrics are described. The criteria for the quality of medical care for patients with septic shock and the algorithms of doctor's actions in the diagnosis and intensive care of patients with septic shock in obstetrics are presented.

Eptifibatide, an Older Therapeutic Peptide with New Indications: From Clinical Pharmacology to Everyday Clinical Practice

Therapeutic peptides are oligomers or short polymers of amino acids used for various medical purposes. Peptide-based treatments have evolved considerably due to new technologies, stimulating new research interests. They have been shown to be beneficial in a variety of therapeutic applications, notably in the treatment of cardiovascular disorders such as acute coronary syndrome (ACS). ACS is characterized by coronary artery wall damage and consequent formation of an intraluminal thrombus obstructing one or more coronary arteries, leading to unstable angina, non-ST elevated myocardial infarction, and ST-elevated myocardial infarction. One of the promising peptide drugs in the treatment of these pathologies is eptifibatide, a synthetic heptapeptide derived from rattlesnake venom. Eptifibatide is a glycoprotein IIb/IIIa inhibitor that blocks different pathways in platelet activation and aggregation. In this narrative review, we summarized the current evidence on the mechanism of action, clinical pharmacology, and applications of eptifibatide in cardiology. Additionally, we illustrated its possible broader usage with new indications, including ischemic stroke, carotid stenting, intracranial aneurysm stenting, and septic shock. Further research is, however, required to fully evaluate the role of eptifibatide in these pathologies, independently and in comparison to other medications.

Epigenetic mechanisms of Immune remodeling in sepsis: targeting histone modification

Sepsis is a life-threatening disorder disease defined as infection-induced dysregulated immune responses and multiple organ dysfunction. The imbalance between hyperinflammation and immunosuppression is a crucial feature of sepsis immunity. Epigenetic modifications, including histone modifications, DNA methylation, chromatin remodeling, and non-coding RNA, play essential roles in regulating sepsis immunity through epi-information independent of the DNA sequence. In recent years, the mechanisms of histone modification in sepsis have received increasing attention, with ongoing discoveries of novel types of histone modifications. Due to the capacity for prolonged effects on immune cells, histone modifications can induce immune cell reprogramming and participate in the long-term immunosuppressed state of sepsis. Herein, we systematically review current mechanisms of histone modifications involved in the regulation of sepsis, summarize their role in sepsis from an immune perspective and provide potential therapeutic opportunities targeting histone modifications in sepsis treatment.

Immunoregulatory functions of mature CD10+ and immature CD10- neutrophils in sepsis patients

Introduction

Neutrophil plays a more and more important role in sepsis with paralysis of immunoregulation. Till now, there was no biomarker to identify and isolate the mature and immature neutrophils in sepsis patients. CD10 shows on mature neutrophils at the latest stages of its differentiation. Our study aimed to investigate whether CD10 was a valid biomarker for distinguishing immature and mature neutrophil subgroups under septic conditions and their immunoregulatory effects on lymphocytes.

Methods

Totally 80 healthy volunteers and 107 sepsis patients were recruited in this study. Fluorescence-conjugated anti-CD66b, and anti-CD10 monoclonal antibodies followed by incubation with specific anti-fluorochrome microbeads was used to isolate different subgroups of neutrophils. T cell apoptotic assays and T cell proliferation assays followed by flow cytometry analysis were used to evaluate the immunoregulatory effect of each subgroup of neutrophils.

Results

(1) The cytological morphology of CD10⁺ neutrophils was mature and that of CD10^- neutrophils was immature in sepsis patients. (2) Mature CD10⁺ neutrophils inhibited the proliferation of T cell and immature CD10^- neutrophils promoted the T cell proliferation.

Conclusion

(1) CD10 was a good biomarker to distinguish mature from immature neutrophils in sepsis patients. (2) Mature CD10⁺ and immature CD10^- neutrophils displayed opposite immunoregulatory effects on T cells in sepsis patients.

Endothelial progenitor cells in the host defense response

Extensive injury of endothelial cells in blood vasculature, especially in the microcirculatory system, frequently occurs in hosts suffering from sepsis and the accompanied systemic inflammation. Pathological factors, including toxic components derived from invading microbes, oxidative stress associated with tissue ischemia/reperfusion, and vessel active mediators generated during the inflammatory response, are known to play important roles in mediating endothelial injury. Collapse of microcirculation and tissue edema developed from the failure of endothelial barrier function in vital organ systems, including the lung, brain, and kidney, are detrimental, which often predict fatal outcomes. The host body possesses a substantial capacity for maintaining vascular homeostasis and repairing endothelial damage. Bone marrow and vascular wall niches house endothelial progenitor cells (EPCs). In response to septic challenges, EPCs in their niche environment are rapidly activated for proliferation and angiogenic differentiation. In the meantime, release of EPCs from their niches into the blood stream and homing of these vascular precursors to tissue sites of injury are markedly increased. The recruited EPCs actively participate in host defense against endothelial injury and repair of damage in blood vasculature via direct differentiation into endothelial cells for re-endothelialization as well as production of vessel active mediators to exert paracrine and autocrine effects on angiogenesis/vasculogenesis. In recent years, investigations on significance of EPCs in host defense and molecular signaling mechanisms underlying regulation of the EPC response have achieved substantial progress, which promotes exploration of vascular precursor cell-based approaches for effective prevention and treatment of sepsis-induced vascular injury as well as vital organ system failure.

Bone Marrow Mesenchymal Stem Cells (BMSC) from Exosome with High miR-184 Level Ameliorates Sepsis

This study assesses whether BMSC from exosome with high miR-184 level ameliorates sepsis. BMSC with high miR-184 expression established. RAW264.7 cells were cultivated in vitro and divided into control set, model set, BMSC set and BMSC with high miR-184 level set. The model was established through infection of RAW264.7 cells with LPS followed by analysis of cell proliferation and apoptosis, activity of ROS and SOD, secretion of IL-1β, IL-6 and TNF-α as well as the expression of NF-κB and TRAIL. BMSC set showed significantly upregulated miR-184 expression, increased cell proliferation and SOD activity, reduced ROS activity, decreased secretion of IL-1β, IL-6 and TNF-α as well as the expression of NF-κB and TRAIL. The above changes were more significant in the set of BMSC with overexpression of miR-184. In conclusion, cell proliferation, apoptosis and inflammation in RAW264.7 cells induced with LPS is regulated by BMSC from exosome with high expression of miR-184, which is possibly through restraining the NF-κB and TRAIL and oxidative stress.

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.

Effect of CRRT with oXiris filter on hemodynamic instability in surgical septic shock with AKI: A pilot randomized controlled trial

BACKGROUND

Early identification and timely management of septic AKI continue to represent clinical challenges for intensive care. The aim was to evaluate the effect of renal replacement with oXiris filter on clinical outcomes in septic AKI.

METHODS

This was a single-center randomized controlled trial that enrolled surgical septic shock with AKI patients admitted in the ICU, Renji Hospital, Shanghai Jiao Tong University, School of Medicine from Jan 1, 2021 to Sep 30, 2021, were screened.

RESULTS

Sixteen subjects that met the inclusion and exclusion criteria were randomized into CRRT with AN69-oXiris group (n = 8) and AN69-ST group (n = 8). The PCT and IL-6 concentration decreased significantly after the first treatment compared to pre-CRRT levels in the oXiris group (PCT: 23.46 [4.18, 84.90] vs 52.79 [9.03, 100.00] µg/L, p = 0.046; IL-6: 3080.15 [527.62, 9806.61] vs 10,457.17 [8150.00, 15,528.87] pg/mL, p = 0.043). The levels of lactate decreased by 1.70 [1.03, 2.83] mmol/L after the first CRRT in the oXiris group (p = 0.028). The norepinephrine infusion rate was decreased by 0.06 [0, 0.09], 0.05 [0, 0.23] and 0.11 [0, 0.23] μg/kg/min at 4, 6, and 8 h in the oXiris group compared to the ST group (p = 0.005, 0.038, and 0.017).

CONCLUSION

Using the oXiris filter may improve hemodynamic status during initial CRRT in severe surgical septic shock with AKI. Further large multicenter RCTs are needed to determine the effect of the oXiris filter on patient outcomes. (http://www.chictr.org.cn/index.aspx (ChiCTR2200055732)).