Unfractioned heparin for treatment of sepsis: A randomized clinical trial (The HETRASE Study)

HEPARIN AND DNase I TREAT MYOCARDIAL INJURY IN SEPTIC MICE

ABSTRACT

Background: Sepsis is a life-threatening clinical condition often seen in intensive care units, leading to multi-organ dysfunction. Myocardial injury is a prevalent complication, significantly increasing mortality among sepsis patients. Although heparin is used in sepsis management, its specific effects on myocardial injury and the role of neutrophil extracellular traps (NETs) in this context remain insufficiently understood. Aim: This study investigates the role of unfractionated heparin (UFH) combined with DNase I in reducing myocardial injury in a septic mouse model. Methods: A cecal ligation and puncture (CLP)-induced sepsis model was established in C57BL/6 mice to study myocardial injury. The experimental groups included treatments with UFH, UFH with DNase I, and NETs introduction. Myocardial injury was assessed using hematoxylin and eosin staining, enzyme linked immunosorbent assay for injury markers (creatine kinase MB [CK-MB] and lactate dehydrogenase [LDH]), and Western blotting for inflammatory proteins (TNF-α and IL-6). Differential proteomic analysis using data independent acquisition mass spectrometry and pathway enrichment analysis (Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) were conducted to identify molecular pathways and key proteins affected by the treatments. Results: Single UFH treatment increased the formation of NETs, upregulated TNF-α and IL-6, and increased CK-MB and LDH, worsening myocardial injury. The combination of UFH and DNase I significantly reduced myocardial injury, suppressing NETs formation and inflammation. Proteomic analysis identified crucial pathways related to NETs, metabolism, and complement and coagulation cascades, with proteins Ccn1 and Tagln highlighted as potential therapeutic targets. Conclusion: UFH combined with DNase I effectively alleviates myocardial injury in septic mice by modulating NETs formation and associated inflammatory processes. This study may provide new insights and options for the early use of heparin in the treatment of septic patients, particularly in cases with a higher risk of myocardial injury.

Impact of antiplatelets, anticoagulants and cyclic nucleotide stimulators on neutrophil extracellular traps (NETs) and inflammatory markers during COVID-19

While the association between coronavirus disease-19 (COVID-19) and neutrophils extracellular traps (NETs) is recognized, uncertainties remain regarding its precise onset, timing of resolution and target therapy. To assess changes in inflammatory and NET markers during the first week of COVID-19 hospitalization, and the association with disease severity. "In vitro" experiments investigated the effect of antiplatelets, anticoagulants, and cyclic nucleotide stimulators on NETs release. Prospective cohort study, changes in interleukin (IL)-6, IL-8, IL-17, TNF-α, RANTES, PF4, and citrullinated-H3 (citH3) levels within each outcome group was evaluated using ANOVA. Differences between moderately ill, critically ill, and non-survivors were determined using Kruskal-Wallis and logistic regression. Healthy neutrophils were stimulated with phorbol-12-myristate-13-acetate (PMA) or COVID-19 sera and treated with unfractionated heparin (UFH), low molecular weight heparin (LMWH), aspirin (ASA), ticagrelor, cinaciguat, sildenafil, and milrinone. The proportion of NETosis was assessed using IncuCyte Cell Imager. Of the 125 patients, 40.8% had moderate COVID-19, 40.8% had critical COVID-19 but recovered, and 18.4% died. From admission to hospitalization day 8, IL-6 levels decreased in moderately and critically ill, but not in non-survivors, while citH3 levels increased in critically ill and non-survivors. IL-6, IL-8, and TNF-α levels were associated with critical and fatal COVID-19. The release of NETs by neutrophils stimulated with PMA or COVID-19 sera was decreased in the presence of ASA, UFH, LMWH and cyclic nucleotide stimulators in a dose-dependent manner. In the first week of hospitalization, NET markers rose later than inflammatory markers in severe COVID-19 cases. Cyclic nucleotide stimulators, ASA and heparin may emerge as treatment approaches as they may modulate NETosis.

Acetylsalicylic Acid Treatment in Patients With Sepsis and Septic Shock: A Phase 2, Placebo-Controlled, Randomized Clinical Trial

OBJECTIVES

Platelets play a critical role in the inflammatory response and coagulation. We aimed to evaluate whether the use of acetylsalicylic acid (ASA) would reduce the intensity of organ dysfunction in septic patients.

DESIGN

Randomized, blinded, parallel-group, placebo-controlled trial.

SETTING

Five general ICUs in Brazil.

PATIENTS

Adults with sepsis for no longer than 48 hours who had at least one severe organ dysfunction (lactate > 4 mmol/L, platelets < 100,000/mm3, Pao2/Fio2 ratio < 200, or septic shock).

INTERVENTIONS

Patients were randomized to receive 200 mg of ASA or placebo for 7 days.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the change in the Sequential Organ Failure Assessment (SOFA) score between day 0 and day 7 or date of discharge/death. Safety outcomes were major bleeding and the number of blood transfusions within 14 days. The planned sample size was 218 with interim safety analyses after enrolling 109 and 163 patients. The study was discontinued due to higher frequency of major bleeding in the ASA group. We included 166 patients (ASA: 82 patients, placebo: 84). In the adjusted analysis, there was no difference in the SOFA change between the groups (mean placebo to ASA group difference, 0.60; 95% CI, -0.55 to 1.75; p = 0.30). There were no differences in any of the secondary outcomes. In the intervention group, there were a higher number of serious adverse events (9 [11%] vs. 1 [1.2%]; p = 0.009) and major bleeding (8 [8.5%] vs. 1 [1.2%]; p = 0.02).

CONCLUSIONS

In this population of septic patients, ASA did not reduce the intensity of organ dysfunction. ASA increased the risk of severe bleeding compared with placebo.

Mediating Role of Platelet Count Increase in Unfractionated Heparin Treatment for Sepsis Patients: A Retrospective Cohort Analysis

Aims/Background The role of heparin in sepsis therapy has been widely debated. The controversy surrounding heparin's use as an anticoagulant in sepsis may stem from differences in sepsis definitions, study designs, timing and dosage of drug administration, treatment duration, complications, and patient severity. In this study, we aimed to determine the optimal timing and dosage of heparin in patients with sepsis, identify specific subgroups that could benefit from heparin therapy, and explore laboratory markers to assess its efficacy. Methods This retrospective cohort study was conducted using the Medical Information Mart for Intensive Care-IV dataset. Data from patients with sepsis were extracted based on the Sepsis 3.0 criteria. Patients were categorized according to heparin use. The effectiveness of early and appropriate heparin administration was assessed, and a subgroup analysis was performed to identify patients most likely to benefit from heparin therapy. Additionally, factors mediating the improvement in sepsis prognosis following heparin treatment were analyzed. Results We recruited 4149 participants who met the inclusion criteria, with an overall 28-day mortality rate of 19.5%. There were 2192 individuals in the heparin group and 1957 in the non-heparin group. After propensity score matching, heparin therapy demonstrated a significantly greater effect on reducing both 28-day and 90-day mortality compared to the non-heparin treatment (18.1% vs. 10.7%, p < 0.001; 18.8% vs. 12.6%, p < 0.001). However, the heparin group had a higher incidence of major bleeding (10.9% vs. 6.3%, p = 0.001), increased use of mechanical ventilation (54.3% vs. 45.1%, p < 0.001), and a longer intensive care unit stay (3.6 vs. 2.5 days, p < 0.001) compared to the non-heparin group. Early administration of high-dose heparin improved 28-day survival. Early and adequate heparin administration was more effective than late and insufficient dosing (p < 0.01), except in patients with sepsis who had low white blood cell counts, alkalosis, or reduced platelet counts. The increase in platelet count had a significant mediating effect on the entire cohort (p < 0.001 for the causal mediation effect), with a mediation proportion of 14%. Conclusion Early and adequate heparin administration can significantly improve the prognosis of sepsis. An increase in platelet count may serve as a potential indicator of the effectiveness of heparin therapy in sepsis.

The transition of the criteria for disseminated intravascular coagulation and the targeted patients in randomized controlled trials over the decades: a scoping review

BACKGROUND

Disseminated intravascular coagulation (DIC) is a severe complication in septic patients. The Japanese Ministry of Health and Welfare (JMHW)-DIC criteria, the first DIC criteria, were established in 1983, and several other criteria have been proposed since then, including the International Society on Thrombosis and Haemostasis (ISTH)-overt DIC criteria and the Japanese Association for Acute Medicine (JAAM) DIC criteria. This study aimed to look into the transition of DIC criteria used in randomized controlled trials (RCTs) for sepsis-induced DIC.

METHODS

We searched PubMed, Scopus, and the Cochrane Central Register of Controlled Trials for English-language studies published through September 30, 2023. Two reviewers looked through citations that assessed the DIC criteria used in RCTs and their secondary analyses. Data on DIC diagnostic criteria, patient characteristics, interventions, and results were gathered.

RESULTS

Twenty-one studies (thirteen RCTs: JMHW-DIC in 5, JAAM-DIC in 4, the sepsis-induced coagulopathy (SIC) in 2; and eight secondary analyses: ISTH-overt DIC in 3, single parameter in 5) were eligible for inclusion. Most RCTs were conducted in Japan, using the criteria of JMHW-DIC, which were followed by JAAM-DIC. Recently, SIC has been used in international RCTs. Meanwhile, other countries tended to conduct RCTs that focused on sepsis, with secondary analyses for DIC using the ISTH-overt DIC criteria.

CONCLUSIONS

The criteria used in RCTs have changed over decades, from the JMHW-DIC to the JAAM-DIC criteria, and the ISTH-overt DIC criteria were retained in the secondary analysis. Based on these findings, additional research is needed to determine the best criterion for diagnosing septic patients.

Heparin in sepsis: current clinical findings and possible mechanisms

Sepsis is a clinical syndrome resulting from the interaction between coagulation, inflammation, immunity and other systems. Coagulation activation is an initial factor for sepsis to develop into multiple organ dysfunction. Therefore, anticoagulant therapy may be beneficial for sepsis patients. Heparin possesses a variety of biological activities, so it has a broad prospect in sepsis. Previous studies suggested that patients with sepsis-induced disseminated intravascular coagulation and high disease severity might be suitable for anticoagulant therapy. With the development of artificial intelligence (AI), recent studies have shown that patients with severe coagulation activation represent the targeted patients for anticoagulant therapy in sepsis. However, it remains necessary to accurately define the relevant biomarkers indicative of this phenotype and validate their clinical utility by large randomized controlled trials (RCTs). Analyses of data from early small RCTs, subgroup analyses of large RCTs and meta-analyses have collectively suggested that anticoagulant therapy, particularly the use of heparin, may be an effective approach for managing sepsis patients. Concurrently, debate persists regarding the optimal selection of anticoagulants, proper timing, usage and dosage of administration that should be employed to assess treatment efficacy. The primary mechanisms of heparin are acting on heparan sulfate, histones, high mobility group box 1 and heparin-binding protein, which interfere with the regulation of inflammation, vascular permeability, coagulation, endothelial function and other biological activities. However, the underlying pathophysiological processes mediating the potential therapeutic effects of heparin in the context of sepsis remain incompletely understood and warrant additional rigorous investigation to establish the mechanism more conclusively.

Unfractionated Heparin Enhances Sepsis Prognosis Through Inhibiting Drp1-Mediated Mitochondrial Quality Imbalance

Unfractionated heparin (UFH) is commonly used as an anticoagulant in sepsis treatment and has recently been found to have non-anticoagulant effects, but underlying mechanisms remain unclear. This retrospective clinical data showed that UFH has significant protective effects in sepsis compared to low-molecular-weight heparin and enoxaparin, indicating potential benefits of its non-anticoagulant properties. Recombinant protein chip screening, surface plasmon resonance, and molecular docking data demonstrated that UFH specifically bound to the cytoplasmic Drp1 protein through its zone 2 non-anticoagulant segment. In-vitro experiments verified that UFH's specific binding to Drp1 suppressed Drp1 translocation to mitochondria following "sepsis" challenge, thereby improving mitochondrial morphology, function and metabolism in vascular endothelial cells. Consequently, UHF comprehensively protected mitochondrial quality, thus reducing vascular leakage and improving prognosis in a sepsis rat model. These findings highlight the potential of UFH as a sepsis treatment strategy targeting non-anticoagulation mechanism.

Heparins May Not Be the Optimal Anticoagulants for Sepsis and Sepsis-Associated Disseminated Intravascular Coagulation

Historically, heparin has had the longest historical use as an anticoagulant and continues this day to be the primary therapeutic option for preventing thrombosis and thromboembolism in critically ill hospitalized patients. Heparin is also used to treat sepsis and sepsis-associated disseminated intravascular coagulation (DIC) in various countries. However, the efficacy and safety of heparin for this indication remains controversial, as adequately powered randomized clinical studies have not demonstrated as yet a survival benefit in sepsis and sepsis-associated DIC, despite meta-analyses and propensity analyses reporting improved outcomes without increasing bleeding risk. Further, activated protein C and recombinant thrombomodulin showed greater improvements in outcomes compared with heparin, although these effects were inconclusive. In summary, further research is warranted, despite the ongoing clinical use of heparin for sepsis and sepsis-associated DIC. Based on Japanese guidelines, antithrombin or recombinant thrombomodulin may be a preferable choice if they are accessible.

Understanding, assessing and treating immune, endothelial and haemostasis dysfunctions in bacterial sepsis

The interplay between the immune system, coagulation, and endothelium is critical in regulating the host response to infection. However, in sepsis and other critical illnesses, a dysregulated immune response can lead to excessive alterations in these mechanisms, resulting in coagulopathy, endothelial dysfunction, and multi-organ dysfunction. This review aims to provide a comprehensive analysis of the pathophysiological mechanisms that govern the complex interplay between immune dysfunction, endothelial dysfunction, and coagulation in sepsis. It emphasises clinical significance, evaluation methods, and potential therapeutic interventions. Understanding these mechanisms is essential for developing effective treatments that can modulate the immune response, mitigate thrombosis, restore endothelial function, and ultimately improve patient survival.

Therapeutic Plasma Exchange to Reverse Plasma Failure in Multiple Organ Dysfunction Syndrome

Plasma plays a crucial role in maintaining health through regulating coagulation and inflammation. Both are essential to respond to homeostatic threats such as traumatic injury or microbial infection; however, left unchecked, they can themselves cause damage. A well-functioning plasma regulatory milieu controls the location, intensity, and duration of the response to injury or infection. In contrast, plasma failure can be conceptualized as a state in which these mechanisms are overwhelmed and unable to constrain coagulation and inflammation appropriately. This dysregulated state causes widespread tissue damage and multiple organ dysfunction syndrome. Unlike plasma derangements caused by individual factors, plasma failure is characterized by a heterogeneous set of plasma component deficiencies and excesses. Targeted therapies such as factor replacement or recombinant antibodies are thus inadequate to restore plasma function. Therapeutic plasma exchange offers the unique ability to remove harmful factors and replete exhausted components, thereby reestablishing appropriate regulation of coagulation and inflammation.

Heparin therapy in sepsis and sepsis-associated disseminated intravascular coagulation: a systematic review and meta-analysis

BACKGROUND

Sepsis is a life-threatening condition that affects 49 million people annually. Managing sepsis-associated coagulopathy poses a significant challenge due to its high mortality rates in intensive care. Recent reports suggest that administering heparin may offer potential survival benefits in sepsis and coronavirus disease cases. However, there is currently no established evidence supporting the use of heparin for sepsis. Thus, in this study, we aimed to assess the efficacy of heparin administration in patients with sepsis.

METHODS

A systematic review was conducted following the PRISMA guidelines. The searches included MEDLINE, Cochrane, and Japanese databases up to January 2023. The inclusion criteria consisted of randomized control trials (RCTs) involving adult sepsis patients receiving heparin. The risk of bias was assessed using RoB2, and the data extraction included 28-day mortality and bleeding complications.

RESULTS

Out of 1733 initial articles, only three studies met the inclusion criteria. The analysis, which included 426 patients, showed no significant difference in 28-day and in-hospital mortality between the heparin and control groups (risk ratio [RR] = 0.86, 95% confidence interval [CI]: 0.60-1.24). Subgroup analysis of sepsis-associated disseminated intravascular coagulation (DIC) patients (n = 109) also did not show a significant reduction in mortality (RR = 0.84, 95% CI: 0.51-1.38). Heterogeneity was zero, and no publication bias was observed. Additionally, there was significant difference in bleeding complications (RR = 0.49, 95% CI: 0.24-0.99, p = 0.047).

CONCLUSIONS

This meta-analysis did not demonstrate a survival benefit of heparin administration in patients with sepsis and sepsis-associated DIC. Further investigation into the potential benefits of heparin is warranted. Moreover, the analysis revealed no increase in bleeding risks with heparin administration; instead, a significant reduction in the risk of bleeding was noted.

TRIAL REGISTRATION

This review was preregistered with PROSPERO (registration: CRD42023385091).

Efficacy of unfractionated heparin in patients with moderate sepsis-induced coagulopathy: An observational study

INTRODUCTION

The 2021 Surviving Sepsis Campaign guidelines recommend low-molecular-weight heparin for the prevention of venous thromboembolism in sepsis. However, observational studies suggest that anticoagulants as a whole may benefit severely ill sepsis patients with coagulopathy, but the optimal targets of unfractionated heparin remain unclear. This study investigated which sepsis patients could most benefit from unfractionated heparin.

MATERIALS AND METHODS

In this retrospective observational study, we identified adult sepsis patients requiring urgent hospitalization from 2006 to 2019 using a large-scale Japanese medical database. Patients were divided into two groups: those receiving unfractionated heparin within 72 h of admission and those who did not. We compared in-hospital mortality, major bleeding complications, and thromboembolic events between these groups using a multivariate logistic regression model adjusted for patient and treatment variables. Additionally, we assessed the association between heparin administration and in-hospital mortality across various subgroups.

RESULTS

Among 30,342 sepsis patients, 2520 received early heparin administration, and 27,822 did not. Multivariate logistic regression revealed a significant association between heparin and reduced in-hospital mortality (adjusted OR: 0.735, 95 % CI: 0.596-0.903) but no significant association with major bleeding and thromboembolic risk (adjusted OR: 1.137, 1.243; 95 % CI: 0.926-1.391, 0.853-1.788, respectively). Subgroup analyses suggested significant survival benefits associated with heparin only in the sepsis patients with moderate coagulopathy and sepsis-induced coagulopathy scores of 3 or 4 (adjusted OR: 0.452, 0.625; 95 % CI: 0.265-0.751, 0.410-0.940, respectively).

CONCLUSIONS

Early heparin administration upon admission is associated with lower in-hospital mortality, especially in moderate sepsis-induced coagulopathy, and no significant increase in complications.

The Preventive and Therapeutic Effects of Acute and Severe Inflammatory Disorders with Heparin and Heparinoid

Systematic inflammatory response syndrome (SIRS) and the accompanying sepsis pose a huge threat to human health worldwide. Heparin is a part of the standard supportive care for the disease. However, the molecular mechanism is not fully understood yet, and the potential signaling pathways that play key roles have not yet been elucidated. In this paper, the main findings regarding the molecular mechanisms associated with the beneficial effects of heparin, including inhibiting HMGB-1-driven inflammation reactions, histone-induced toxicity, thrombo-inflammatory response control and the new emerging mechanisms are concluded. To set up the link between the preclinical research and the clinical effects, the outcomes of the clinical trials are summarized. Then, the structure and function relationship of heparin is discussed. By providing an updated analysis of the above results, the paper highlights the feasibility of heparin as a possible alternative for sepsis prophylaxis and therapy.

Emerging therapeutic strategies targeting extracellular histones for critical and inflammatory diseases: an updated narrative review

Extracellular histones are crucial damage-associated molecular patterns involved in the development and progression of multiple critical and inflammatory diseases, such as sepsis, pancreatitis, trauma, acute liver failure, acute respiratory distress syndrome, vasculitis and arthritis. During the past decade, the physiopathologic mechanisms of histone-mediated hyperinflammation, endothelial dysfunction, coagulation activation, neuroimmune injury and organ dysfunction in diseases have been systematically elucidated. Emerging preclinical evidence further shows that anti-histone strategies with either their neutralizers (heparin, heparinoids, nature plasma proteins, small anion molecules and nanomedicines, etc.) or extracorporeal blood purification techniques can significantly alleviate histone-induced deleterious effects, and thus improve the outcomes of histone-related critical and inflammatory animal models. However, a systemic evaluation of the efficacy and safety of these histone-targeting therapeutic strategies is currently lacking. In this review, we first update our latest understanding of the underlying molecular mechanisms of histone-induced hyperinflammation, endothelial dysfunction, coagulopathy, and organ dysfunction. Then, we summarize the latest advances in histone-targeting therapy strategies with heparin, anti-histone antibodies, histone-binding proteins or molecules, and histone-affinity hemoadsorption in pre-clinical studies. Finally, challenges and future perspectives for improving the clinical translation of histone-targeting therapeutic strategies are also discussed to promote better management of patients with histone-related diseases.

Inflammation, Sepsis, and the Coagulation System

Sepsis has been a major health problem for centuries and it is still the leading cause of hospital deaths. Several studies in the past decades have identified numerous biochemical abnormalities in severe cases, and many of these studies provide evidence of the perturbation of the hemostatic system. This can result in complications, such as disseminated intravascular coagulation that can lead to multiorgan failure. Nevertheless, large clinical studies have demonstrated that the simple approach of inhibiting the coagulation processes by any means fails to provide significant improvement in the survival of septic patients. A cause of this failure could be the fact that in sepsis the major clinical problems result not primarily from the presence of the infective agent or enhanced coagulation but from the complex dysregulated systemic host response to pathogens. If this overt reaction is not fully deciphered, appropriate interference is highly unlikely and any improvement by conventional therapeutic interventions would be limited. Cellular activation in sepsis can be targeted by novel approaches like inhibition of the heterotypic cellular interactions of blood cells by targeting surface receptors or posttranscriptional control of the hemostatic system by noncoding ribonucleic acid (RNA) molecules. Stable RNA molecules can affect the expression of several proteins. Thus, it can be anticipated that modulation of microRNA production would result in a multitude of effects that may be beneficial in septic cases. Here, we highlight some of the recent diagnostic possibilities and potential novel routes of the dysregulated host response.

Cathepsin C from extracellular histone-induced M1 alveolar macrophages promotes NETosis during lung ischemia-reperfusion injury

Primary graft dysfunction (PGD) is a severe form of acute lung injury resulting from lung ischemia/reperfusion injury (I/R) in lung transplantation (LTx), associated with elevated post-transplant morbidity and mortality rates. Neutrophils infiltrating during reperfusion are identified as pivotal contributors to lung I/R injury by releasing excessive neutrophil extracellular traps (NETs) via NETosis. While alveolar macrophages (AMs) are involved in regulating neutrophil chemotaxis and infiltration, their role in NETosis during lung I/R remains inadequately elucidated. Extracellular histones constitute the main structure of NETs and can activate AMs. In this study, we confirmed the significant involvement of extracellular histone-induced M1 phenotype of AMs (M1-AMs) in driving NETosis during lung I/R. Using secretome analysis, public protein databases, and transwell co-culture models of AMs and neutrophils, we identified Cathepsin C (CTSC) derived from AMs as a major mediator in NETosis. Further elucidating the molecular mechanisms, we found that CTSC induced NETosis through a pathway dependent on NADPH oxidase-mediated production of reactive oxygen species (ROS). CTSC could significantly activate p38 MAPK, resulting in the phosphorylation of the NADPH oxidase subunit p47phox, thereby facilitating the trafficking of cytoplasmic subunits to the cell membrane and activating NADPH oxidase. Moreover, CTSC up-regulated and activated its substrate membrane proteinase 3 (mPR3), resulting in an increased release of NETosis-related inflammatory factors. Inhibiting CTSC revealed great potential in mitigating NETosis-related injury during lung I/R. These findings suggests that CTSC from AMs may be a crucial factor in mediating NETosis during lung I/R, and targeting CTSC inhition may represent a novel intervention for PGD in LTx.

Extracellular histones promote TWIK2-dependent potassium efflux and associated NLRP3 activation in alveolar macrophages during sepsis-induced lung injury

BACKGROUND AND AIM

Sepsis-induced acute lung injury (ALI) is a complex and life-threatening condition lacking specific and efficient clinical treatments. Extracellular histones, identified as a novel type of damage-associated molecular patterns, have been implicated in the inflammatory process of ALI. However, further elucidation is needed regarding the precise mechanism through which extracellular histones induce inflammation. The aim of this study was to investigate whether extracellular histones can activate NLRP3 inflammasome-mediated inflammation in alveolar macrophages (AMs) by affecting TWIK2-dependent potassium efflux.

METHODS AND RESULTS

We conducted experiments using cecal ligation and puncture (CLP) C57BL/6 mice and extracellular histone-stimulated LPS-primed MH-S cells. The results demonstrated a significant increase in the levels of extracellular histones in the plasma and bronchoalveolar lavage fluid (BALF) of CLP mice. Furthermore, neutralizing extracellular histone mitigated lung injury and inflammation in CLP-induced ALI mice. In vitro studies confirmed that extracellular histones upregulated the expression of NLRP3 inflammasome activation-related proteins in MH-S cells, and this effect was dependent on increased potassium efflux mediated by the TWIK2 channel on the plasma membrane. Moreover, extracellular histones directly triggered a substantial influx of calcium, leading to increased Rab11 activity and facilitating the trafficking and location of TWIK2 to the plasma membrane.

CONCLUSION

These findings underscore the critical role of extracellular histone-induced upregulation of TWIK2 expression on the plasma membrane of alveolar macrophages (AMs). This upregulation leads to potassium efflux and subsequent activation of the NLRP3 inflammasome, ultimately exacerbating lung inflammation and injury during sepsis.

Association Between Nonthyroidal Illness Syndrome and Disseminated Intravascular Coagulation in Sepsis

PURPOSE

Both nonthyroidal illness syndrome (NTIS) and disseminated intravascular coagulation (DIC) are commonly occurred in sepsis. The objective of this study is to evaluate the association between NTIS and DIC, as well as their impacts on the mortality in adults with sepsis.

PATIENTS AND METHODS

A total of 1219 septic patients in two Chinese academic centers from October 2012 and October 2022 were enrolled in analysis. We conduct logistic regression models to analyze the independent risk factors for DIC. Modified Poisson regression models are used to estimate the relative risk (RR) of NTIS on the 28 days mortality in septic patients with DIC. Correlation analysis between thyroid function parameters and coagulation parameters is performed with Pearson coefficient be reported.

RESULTS

DIC is diagnosed on 388 (31.8%) of all the 1219 enrolled septic patients within 72 hours after admission. In multivariate logistic regression models, NTIS (OR 3.19; CI 2.31-4.46; p<0.001) is a statistically significant independent risk factor for DIC after adjustment for potential confounders. Twenty-eight days mortality is significantly higher in DIC patients complicated with NTIS compared with the other DIC patients (23.2% vs 14.0%, p=0.024). This result is also robust in different modified Poisson regression models (Model 1: RR 1.46; CI 1.25-1.70; p<0.001; Model 2: RR 1.35; CI 1.14-1.60; p<0.001; Model 3: RR 1.18; CI 1.02-1.37; p=0.026). Correlation analysis reveals that the thyroid function parameters of FT3, FT4 and TSH only have weak correlations with coagulation parameters of platelet count, fibrinogen, FDP, D-dimers, PT, APTT and INR in sepsis.

CONCLUSION

NTIS is an independent risk factor for DIC in adults with sepsis. DIC patients complicated with NTIS have significantly higher severity and higher rate of mortality.

Efficacy and safety of heparin for sepsis-induced disseminated intravascular coagulation (HepSIC): study protocol for a multicenter randomized controlled trial

BACKGROUND

Disseminated intravascular coagulation (DIC) occurs in 30-50% of septic patients and contributes to high mortality in the intensive care unit (ICU). However, there are few proven interventions for coagulation disorder management in sepsis. Experimental and clinical data have demonstrated that sepsis could benefit from unfractionated heparin (UFH) treatment. To date, there are no large multicenter trials to determine the safety and efficacy of UFH in septic patients with suspected DIC.

METHODS

A multicenter, double-blinded, placebo-controlled randomized trial is designed to recruit 600 patients who met sepsis 3.0 criteria and suspected DIC. Participants will be randomized (1:1) to receive UFH or saline via continuous intravenous administration for 7 days within 6 h of enrolment. The primary outcome is ICU mortality. The secondary outcome includes 28-day all-cause mortality, the improvement of Sequential Organ Failure Assessment scores, and the incidence of major hemorrhage. Investigators, participants, and statisticians will be blinded to the allocation.

DISCUSSION

The HepSIC trial is to evaluate the efficacy and safety of UFH on sepsis-related DIC across different areas of China. The small dosage of UFH administration would offer a new potential approach for treating sepsis-related coagulation disorders.

ETHICS AND DISSEMINATION

Ethical approval was granted by all the ethics committees of 20 participant centers. Results will be disseminated via peer-reviewed publications and presented at conferences.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02654561. Registered on 13 January 2016.

The Polyanionic Drug Suramin Neutralizes Histones and Prevents Endotheliopathy

Drugs are needed to protect against the neutrophil-derived histones responsible for endothelial injury in acute inflammatory conditions such as trauma and sepsis. Heparin and other polyanions can neutralize histones but challenges with dosing or side effects such as bleeding limit clinical application. In this study, we demonstrate that suramin, a widely available polyanionic drug, completely neutralizes the toxic effects of individual histones, but not citrullinated histones from neutrophil extracellular traps. The sulfate groups on suramin form stable electrostatic interactions with hydrogen bonds in the histone octamer with a dissociation constant of 250 nM. In cultured endothelial cells (Ea.Hy926), histone-induced thrombin generation was significantly decreased by suramin. In isolated murine blood vessels, suramin abolished aberrant endothelial cell calcium signals and rescued impaired endothelial-dependent vasodilation caused by histones. Suramin significantly decreased pulmonary endothelial cell ICAM-1 expression and neutrophil recruitment caused by infusion of sublethal doses of histones in vivo. Suramin also prevented histone-induced lung endothelial cell cytotoxicity in vitro and lung edema, intra-alveolar hemorrhage, and mortality in mice receiving a lethal dose of histones. Protection of vascular endothelial function from histone-induced damage is a novel mechanism of action for suramin with therapeutic implications for conditions characterized by elevated histone levels.

Effectiveness of early heparin therapy on outcomes in critically ill patients with sepsis-induced coagulopathy

Background: This study aimed to investigate whether early unfractionated heparin (UFH) administration provides a survival advantage for patients with sepsis-induced coagulopathy (SIC). Methods: Patients hospitalized with sepsis-induced coagulopathy from the Medical Information Mart for Intensive Care (MIMIC)-IV database were identified. Patients were divided into two groups, who received unfractionated heparin (UFH) subcutaneously within 24 h after intensive care unit (ICU) admission, and the control group, who received not. The primary endpoint was intensive care unit mortality, the secondary outcomes were 7, 14, and 28-day and hospital mortality. Propensity score matching (PSM) the marginal structural Cox model (MSCM) and E-value analysis were used to account for baseline differences, time-varying and unmeasured confounding factors. Results: A total of 3,377 patients with sepsis-induced coagulopathy were enrolled in the study, of which 815 in unfractionated heparin group and 2,562 in control group. There was significant effect on primary and secondary outcomes with unfractionated heparin after propensity score matching (intensive care unit mortality, hazard ratio [HR] 0.69, 95% confidence interval [CI] 0.52-0.92; 7-day, HR 0.70, 95% CI 0.49-0.99; 14-day, HR 0.68.95% CI 0.50-0.92; 28-day, HR 0.72, 95% CI 0.54-0.96; hospital mortality, HR 0.74, 95% CI 0.57-0.96), marginal structural Cox model manifested unfractionated heparin associated with decreased intensive care unit mortality in all populations (HR 0.64, 95% CI 0.49-0.84), and stratification with the marginal structural Cox model indicated analysis further indicated the survival advantage only among patients with an sepsis-induced coagulopathy score of 4 (HR 0.56, 95% CI 0.38-0.81). Further analysis showed that treatment with 6,250-13750 IU/day of unfractionated heparin associated with a decreased risk of intensive care unit mortality. Similar results were replicated in subgroup analysis with propensity score matching only for patients with an sepsis-induced coagulopathy score of 4 (intensive care unit mortality, HR 0.51, 95% CI 0.34-0.76). Conclusion: This study found early unfractionated heparin therapy to patients with sepsis-induced coagulopathy appears to be associated with improved outcomes. Subgroup analysis further demonstrates heparin therapy decreased intensive care unit mortality primarily in patients only with SIC score of 4.

The effect of antithrombotic treatment on mortality in patients with acute infection: A meta-analysis of randomized clinical trials

BACKGROUND AND AIMS

Acute infections cause relevant activation of innate immunity and inflammatory cascade. An excessive response against pathogens has been proved to trigger the pathophysiological process of thrombo-inflammation. Nevertheless, an association between the use of antithrombotic agents and the outcome of critically ill patients with infectious diseases is lacking. The aim of this meta-analysis is to determine the impact of antithrombotic treatment on survival of patients with acute infective disease.

METHODS

MEDLINE, Embase, Cinahl, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL) databases were systematically searched from inception to March 2021. We included randomized controlled trials (RCTs) that evaluated any antithrombotic agent in patients with infectious diseases other than COVID-19. Two authors independently performed study selection, data extraction and risk of bias evaluation. The primary outcome was all-cause mortality. Summary estimates for mortality were calculated using the inverse-variance random-effects method.

RESULTS

A total of 16,588 patients participating in 18 RCTs were included, of whom 2141 died. Four trials evaluated therapeutic-dose anticoagulation, 1 trial prophylactic-dose anticoagulation, 4 trials aspirin, and 9 trials other antithrombotic agents. Overall, the use of antithrombotic agents was not associated with all-cause mortality (relative risk 0.96; 95% confidence interval, 0.90-1.03).

CONCLUSIONS

The use of antithrombotics is not associated with all-cause mortality in patients with infectious disease other than COVID-19. Complex pathophysiological interplays between inflammatory and thrombotic pathways may explain these results and need further investigation.

REGISTRATION

PROSPERO, CRD42021241182.

A 3-O-sulfated heparan sulfate dodecasaccharide (12-mer) suppresses thromboinflammation and attenuates early organ injury following trauma and hemorrhagic shock

Introduction

Dysregulated inflammation and coagulation are underlying mechanisms driving organ injury after trauma and hemorrhagic shock. Heparan sulfates, cell surface glycosaminoglycans abundantly expressed on the endothelial surface, regulate a variety of cellular processes. Endothelial heparan sulfate containing a rare 3-O-sulfate modification on a glucosamine residue is anticoagulant and anti-inflammatory through high-affinity antithrombin binding and sequestering of circulating damage-associated molecular pattern molecules. Our goal was to evaluate therapeutic potential of a synthetic 3-O-sulfated heparan sulfate dodecasaccharide (12-mer, or dekaparin) to attenuate thromboinflammation and prevent organ injury.

Methods

Male Sprague-Dawley rats were pre-treated subcutaneously with vehicle (saline) or dekaparin (2 mg/kg) and subjected to a trauma/hemorrhagic shock model through laparotomy, gut distention, and fixed-pressure hemorrhage. Vehicle and dekaparin-treated rats were resuscitated with Lactated Ringer's solution (LR) and compared to vehicle-treated fresh-frozen-plasma-(FFP)-resuscitated rats. Serial blood samples were collected at baseline, after induction of shock, and 3 hours after fluid resuscitation to measure hemodynamic and metabolic shock indicators, inflammatory mediators, and thrombin-antithrombin complex formation. Lungs and kidneys were processed for organ injury scoring and immunohistochemical analysis to quantify presence of neutrophils.

Results

Induction of trauma and hemorrhagic shock resulted in significant increases in thrombin-antithrombin complex, inflammatory markers, and lung and kidney injury scores. Compared to vehicle, dekaparin treatment did not affect induction, severity, or recovery of shock as indicated by hemodynamics, metabolic indicators of shock (lactate and base excess), or metrics of bleeding, including overall blood loss, resuscitation volume, or hematocrit. While LR-vehicle-resuscitated rodents exhibited increased lung and kidney injury, administration of dekaparin significantly reduced organ injury scores and was similar to organ protection conferred by FFP resuscitation. This was associated with a significant reduction in neutrophil infiltration in lungs and kidneys and reduced lung fibrin deposition among dekaparin-treated rats compared to vehicle. No differences in organ injury, neutrophil infiltrates, or fibrin staining between dekaparin and FFP groups were observed. Finally, dekaparin treatment attenuated induction of thrombin-antithrombin complex and inflammatory mediators in plasma following trauma and hemorrhagic shock.

Conclusion

Anti-thromboinflammatory properties of a synthetic 3-O-sulfated heparan sulfate 12-mer, dekaparin, could provide therapeutic benefit for mitigating organ injury following major trauma and hemorrhagic shock.

Endothelial dysfunction and immunothrombosis in sepsis

Sepsis is a life-threatening clinical syndrome characterized by multiorgan dysfunction caused by a dysregulated or over-reactive host response to infection. During sepsis, the coagulation cascade is triggered by activated cells of the innate immune system, such as neutrophils and monocytes, resulting in clot formation mainly in the microcirculation, a process known as immunothrombosis. Although this process aims to protect the host through inhibition of the pathogen’s dissemination and survival, endothelial dysfunction and microthrombotic complications can rapidly lead to multiple organ dysfunction. The development of treatments targeting endothelial innate immune responses and immunothrombosis could be of great significance for reducing morbidity and mortality in patients with sepsis. Medications modifying cell-specific immune responses or inhibiting platelet–endothelial interaction or platelet activation have been proposed. Herein, we discuss the underlying mechanisms of organ-specific endothelial dysfunction and immunothrombosis in sepsis and its complications, while highlighting the recent advances in the development of new therapeutic approaches aiming at improving the short- or long-term prognosis in sepsis.

Heparan sulfates and heparan sulfate binding proteins in sepsis

Heparan sulfates (HSs) are the main components in the glycocalyx which covers endothelial cells and modulates vascular homeostasis through interactions with multiple Heparan sulfate binding proteins (HSBPs). During sepsis, heparanase increases and induces HS shedding. The process causes glycocalyx degradation, exacerbating inflammation and coagulation in sepsis. The circulating heparan sulfate fragments may serve as a host defense system by neutralizing dysregulated Heparan sulfate binding proteins or pro-inflammatory molecules in certain circumstances. Understanding heparan sulfates and heparan sulfate binding proteins in health and sepsis is critical to decipher the dysregulated host response in sepsis and advance drug development. In this review, we will overview the current understanding of HS in glycocalyx under septic condition and the dysfunctional heparan sulfate binding proteins as potential drug targets, particularly, high mobility group box 1 (HMGB1) and histones. Moreover, several drug candidates based on heparan sulfates or related to heparan sulfates, such as heparanase inhibitors or heparin-binding protein (HBP), will be discussed regarding their recent advances. By applying chemical or chemoenzymatic approaches, the structure-function relationship between heparan sulfates and heparan sulfate binding proteins is recently revealed with structurally defined heparan sulfates. Such homogenous heparan sulfates may further facilitate the investigation of the role of heparan sulfates in sepsis and the development of carbohydrate-based therapy.

Heparin, Heparan Sulphate and Sepsis: Potential New Options for Treatment

Sepsis is a life-threatening hyperreaction to infection in which excessive inflammatory and immune responses cause damage to host tissues and organs. The glycosaminoglycan heparan sulphate (HS) is a major component of the cell surface glycocalyx. Cell surface HS modulates several of the mechanisms involved in sepsis such as pathogen interactions with the host cell and neutrophil recruitment and is a target for the pro-inflammatory enzyme heparanase. Heparin, a close structural relative of HS, is used in medicine as a powerful anticoagulant and antithrombotic. Many studies have shown that heparin can influence the course of sepsis-related processes as a result of its structural similarity to HS, including its strong negative charge. The anticoagulant activity of heparin, however, limits its potential in treatment of inflammatory conditions by introducing the risk of bleeding and other adverse side-effects. As the anticoagulant potency of heparin is largely determined by a single well-defined structural feature, it has been possible to develop heparin derivatives and mimetic compounds with reduced anticoagulant activity. Such heparin mimetics may have potential for use as therapeutic agents in the context of sepsis.

Unfractionated Heparin Protects Microcirculation in Endotoxemic Rats by Antagonizing Histones

INTRODUCTION

Levels of extracellular histones are highly increased in sepsis and may facilitate microcirculatory dysfunction. Unfractionated heparin (UFH) binds histones and neutralizes their cytotoxicity. We investigated the effect of UFH on microcirculatory dysfunction by interacting with extracellular histones in endotoxemic rats.

METHODS

Twenty-four Wistar rats were randomly divided into three groups: control, lipopolysaccharide (LPS) group, and LPS + UFH group. In the LPS and LPS + UFH groups, 10 mg/kg LPS was injected to induce endotoxemia, and 100 IU/kg/h UFH was administered intravenously in the LPS + UFH group. The rats underwent midline laparotomy, and then intestinal microcirculation was evaluated using an incident dark field microscope. Circulating histones and microstructures of the rat intestinal microvascular endothelium were also detected. Additionally, the antagonistic effect of UFH on histone-induced cytotoxicity was investigated in human intestinal microvascular endothelial cells.

RESULTS

UFH protected the microcirculation of the intestinal serosa and mucosa in endotoxemic rats, as evidenced by increased total vessel density, perfused vessel density, and proportion of perfused vessels of both the serosa and mucosa, and increased microcirculatory flow index of the mucosa in the LPS + UFH group. UFH treatment decreased the levels of circulating histones and alleviated intestinal microvascular endothelial injuries in endotoxemic rats. Furthermore, UFH inhibited histone cytotoxicity in vitro.

CONCLUSIONS

UFH attenuated microcirculatory dysfunction in endotoxemic rats by antagonizing extracellular histones, thereby providing a potential therapeutic strategy for sepsis.

Role of pyroptosis in hemostasis activation in sepsis

Sepsis is frequently associated with hemostasis activation and thrombus formation, and systematic hemostatic changes are associated with a higher risk of mortality. The key events underlying hemostasis activation during sepsis are the strong activation of innate immune pathways and the excessive inflammatory response triggered by invading pathogens. Pyroptosis is a proinflammatory form of programmed cell death, that defends against pathogens during sepsis. However, excessive pyroptosis can lead to a dysregulation of host immune responses and organ dysfunction. Recently, pyroptosis has been demonstrated to play a prominent role in hemostasis activation in sepsis. Several studies have demonstrated that pyroptosis participates in the release and coagulation activity of tissue factors. In addition, pyroptosis activates leukocytes, endothelial cells, platelets, which cooperate with the coagulation cascade, leading to hemostasis activation in sepsis. This review article attempts to interpret the molecular and cellular mechanisms of the hemostatic imbalance induced by pyroptosis during sepsis and discusses potential therapeutic strategies.

Anticoagulant therapies against sepsis-induced disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC) is a frequent but lethal complication in sepsis. Anticoagulant therapies, such as heparin, antithrombin, activated protein C, and recombinant human-soluble thrombomodulin, were expected to regulate the progression of coagulopathy in sepsis. Although a number of randomized controlled trials (RCTs) have evaluated the survival effects of these therapies over the past few decades, there remains no consistent evidence showing a significant survival benefit of anticoagulant therapies. Currently, anticoagulant therapies are not conducted as a standard treatment against sepsis in many countries and regions. However, most of these RCTs were performed overall in patients with sepsis but not in those with sepsis-induced DIC, who were theoretically the optimal target population of anticoagulants. Actually, multiple lines of evidence from observational studies and meta-analyses of the RCTs have suggested that anticoagulant therapies might reduce mortality only when used in septic DIC. In addition, the severity of illness is another essential factor that maximally affects the efficacy of the therapy. Therefore, to provide evidence on the true effect of anticoagulant therapies, the next RCTs must be designed to enroll only patients with sepsis-induced overt DIC and a high severity of illness. To prepare these future RCTs, a novel scientific infrastructure for accurate detection of patients who can receive maximal benefit from anticoagulant therapies also needs to be established.

Early prophylactic anticoagulation with heparin alleviates mortality in critically ill patients with sepsis: a retrospective analysis from the MIMIC-IV database

Background

Minimal data exist on anticoagulation use and timing and the dose of heparin in patients with sepsis, and whether heparin use improves sepsis survival remains largely unclear. This study was performed to assess whether heparin administration would provide a survival advantage in critically ill patients with sepsis.

Methods

A retrospective cohort study of patients with sepsis in the Medical Information Mart for Intensive Care (MIMIC)-IV database was conducted. Cox proportional hazards model and propensity score matching (PSM) were used to evaluate the outcomes of prophylactic anticoagulation with heparin administered by subcutaneous injection within 48 h of intensive care unit (ICU) admission. The primary outcome was in-hospital mortality. Secondary outcomes included 60-day mortality, length of ICU stay, length of hospital stay and incidence of acute kidney injury (AKI) on day 7. E-Value analysis were used for unmeasured confounding.

Results

A total of 6646 adult septic patients were included and divided into an early prophylactic heparin group (n = 3211) and a nonheparin group (n = 3435). In-hospital mortality in the heparin therapy group was significantly lower than that in the nonheparin group (prematched 14.7 vs 20.0%, hazard ratio (HR) 0.77, 95% confidence interval (CI) [0.68-0.87], p < 0.001, and postmatched 14.9 vs 18.3%, HR 0.78, 95% CI [0.68-0.89], p < 0.001). Secondary endpoints, including 60-day mortality and length of ICU stay, differed between the heparin and nonheparin groups (p < 0.01). Early prophylactic heparin administration was associated with in-hospital mortality among septic patients in different adjusted covariates (HR 0.71-0.78, p < 0.001), and only administration of five doses of heparin was associated with decreased in-hospital mortality after PSM (HR 0.70, 95% CI 0.56-0.87, p < 0.001). Subgroup analysis showed that heparin use was significantly associated with reduced in-hospital mortality in patients with sepsis-induced coagulopathy, septic shock, sequential organ failure assessment score ≥ 10, AKI, mechanical ventilation, gram-positive bacterial infection and gram-negative bacterial infection, with HRs of 0.74, 0.70, 0.58, 0.74, 0.73, 0.64 and 0.72, respectively (p <0.001). E-Value analysis suggested robustness to unmeasured confounding.

Conclusions

This study found an association between early administration prophylactic heparin provided to patients with sepsis and reduced risk-adjusted mortality. A prospective randomized-controlled study should be designed to further assess the relevant findings.

A potential new pathway for heparin treatment of sepsis-induced lung injury: inhibition of pulmonary endothelial cell pyroptosis by blocking hMGB1-LPS-induced caspase-11 activation

Sepsis is a significant cause of mortality in critically ill patients. Acute lung injury (ALI) is a leading cause of death in these patients. Endothelial cells exposed to the bacterial endotoxin lipopolysaccharide (LPS) can progress into pyroptosis, a programmed lysis of cell death triggered by inflammatory caspases. It is characterized by lytic cell death induced by the binding of intracellular LPS to caspases 4/5 in human cells and caspase-11 in mouse cells. In mice,caspase-11-dependent pyroptosis plays an important role in endotoxemia. HMGB1 released into the plasma binds to LPS and is internalized into lysosomes in endothelial cells via the advanced glycation end product receptor. In the acidic lysosomal environment, HMGB1 permeates the phospholipid bilayer, which is followed by the leakage of LPS into the cytoplasm and the activation of caspase-11. Heparin is an anticoagulant widely applied in the treatment of thrombotic disease. Previous studies have found that heparin could block caspase-11-dependent inflammatory reactions, decrease sepsis-related mortality, and reduce ALI, independent of its anticoagulant activity. Heparin or modified heparin with no anticoagulant property could inhibit the alarmin HMGB1-LPS interactions, minimize LPS entry into the cytoplasm, and thus blocking caspase-11 activation. Heparin has been studied in septic ALI, but the regulatory mechanism of pulmonary endothelial cell pyroptosis is still unclear. In this paper, we discuss the potential novel role of heparin in the treatment of septic ALI from the unique mechanism of pulmonary endothelial cell pyroptosis.

Chasing the Ghost: Hyperinflammation Does Not Cause Sepsis

Sepsis is infection sufficient to cause illness in the infected host, and more severe forms of sepsis can result in organ malfunction or death. Severe forms of Coronavirus disease-2019 (COVID-19), or disease following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are examples of sepsis. Following infection, sepsis is thought to result from excessive inflammation generated in the infected host, also referred to as a cytokine storm. Sepsis can result in organ malfunction or death. Since COVID-19 is an example of sepsis, the hyperinflammation concept has influenced scientific investigation and treatment approaches to COVID-19. However, decades of laboratory study and more than 100 clinical trials designed to quell inflammation have failed to reduce sepsis mortality. We examine theoretical support underlying widespread belief that hyperinflammation or cytokine storm causes sepsis. Our analysis shows substantial weakness of the hyperinflammation approach to sepsis that includes conceptual confusion and failure to establish a cause-and-effect relationship between hyperinflammation and sepsis. We conclude that anti-inflammation approaches to sepsis therapy have little chance of future success. Therefore, anti-inflammation approaches to treat COVID-19 are likewise at high risk for failure. We find persistence of the cytokine storm concept in sepsis perplexing. Although treatment approaches based on the hyperinflammation concept of pathogenesis have failed, the concept has shown remarkable resilience and appears to be unfalsifiable. An approach to understanding this resilience is to consider the hyperinflammation or cytokine storm concept an example of a scientific paradigm. Thomas Kuhn developed the idea that paradigms generate rules of investigation that both shape and restrict scientific progress. Intrinsic features of scientific paradigms include resistance to falsification in the face of contradictory data and inability of experimentation to generate alternatives to a failing paradigm. We call for rejection of the concept that hyperinflammation or cytokine storm causes sepsis. Using the hyperinflammation or cytokine storm paradigm to guide COVID-19 treatments is likewise unlikely to provide progress. Resources should be redirected to more promising avenues of investigation and treatment.

Age-related differences in the survival benefit of the administration of antithrombin, recombinant human thrombomodulin, or their combination in sepsis

Disseminated intravascular coagulation (DIC) is one of the major organ dysfunctions associated with sepsis. This retrospective secondary analysis comprised data from a prospective multicenter study to investigate the age-related differences in the survival benefit of anticoagulant therapy in sepsis according to the DIC diagnostic criteria. Adult patients with severe sepsis based on the Sepsis-2 criteria were enrolled and divided into the following groups: (1) anticoagulant group (patients who received anticoagulant therapy) and (2) non-anticoagulant group (patients who did not receive anticoagulant therapy). Patients in the former group were administered antithrombin, recombinant human thrombomodulin, or their combination. The increases in the risk of hospital mortality were suppressed in the high-DIC-score patients aged 60-70 years receiving anticoagulant therapy. No favorable association of anti-coagulant therapy with hospital mortality was observed in patients aged 50 years and 80 years. Furthermore, anticoagulant therapy in the lower-DIC-score range increased the risk of hospital mortality in patients aged 50-60 years. In conclusion, anticoagulant therapy was associated with decreased hospital mortality according to a higher DIC score in septic patients aged 60-70 years. Anticoagulant therapy, however, was not associated with a better outcome in relatively younger and older patients with sepsis.

A propensity score-matching analysis of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker exposure on in-hospital mortality in patients with acute respiratory failure

STUDY OBJECTIVE

To explore the impact of pre-hospital ACEI and ARB exposure on the prognosis of ARF patients.

DESIGN

A single-center retrospective cohort study.

SETTING

Medical Information Mart for Intensive Care-III (MIMIC-III) database.

PATIENTS

The patients meeting ICD-9 code of acute respiratory failure were enrolled.

INTERVENTION

The primary exposure was the pre-hospital exposure of ACEI and ARB.

MEASUREMENT AND MAIN RESULTS

The primary outcome was in-hospital mortality. Multiple logistic regression analysis was conducted to determine the independent effect of ACEI/ARB exposure on mortality. Propensity score matching (PSM) method was adopted to reduce bias of the confounders. Subgroup analysis and sensitivity analysis were used to test the stability of the conclusion. 5335 adult ARF patients were enrolled. Mortality was significantly decreased in patients with ACEI/ARB exposure before and after PSM, and the adjusted odds ratio (OR) of ACEI/ARB exposure was 0.56 (95% CI 0.43-0.72). In the subgroup analysis, ACEI/ARB lost its protective effect in young subgroup, but no significant interaction was found between ACEI/ARB exposure and age (p = 0.082). The point estimation and lower 95% limit of E-value was 2.97 and 2.12. In sensitivity analysis, ACEI/ARB exposure showed similar effect in ARDS cohort, but no significantly difference was found in the MIMIC-IV database, which may be explained by small sample size of the ACEI/ARB group.

CONCLUSIONS

Among patients with acute respiratory failure, pre-hospital ACEI/ARB exposure was associated with better outcomes and acted as an independent factor. The relationship between ACEI/ARB and prognosis of ARF is worth investigating further.

Coagulation System Activation for Targeting of COVID-19: Insights into Anticoagulants, Vaccine-Loaded Nanoparticles, and Hypercoagulability in COVID-19 Vaccines

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as COVID-19, is currently developing into a rapidly disseminating and an overwhelming worldwide pandemic. In severe COVID-19 cases, hypercoagulability and inflammation are two crucial complications responsible for poor prognosis and mortality. In addition, coagulation system activation and inflammation overlap and produce life-threatening complications, including coagulopathy and cytokine storm, which are associated with overproduction of cytokines and activation of the immune system; they might be a lead cause of organ damage. However, patients with severe COVID-19 who received anticoagulant therapy had lower mortality, especially with elevated D-dimer or fibrin degradation products (FDP). In this regard, the discovery of natural products with anticoagulant potential may help mitigate the numerous side effects of the available synthetic drugs. This review sheds light on blood coagulation and its impact on the complication associated with COVID-19. Furthermore, the sources of natural anticoagulants, the role of nanoparticle formulation in this outbreak, and the prevalence of thrombosis with thrombocytopenia syndrome (TTS) after COVID-19 vaccines are also reviewed. These combined data provide many research ideas related to the possibility of using these anticoagulant agents as a treatment to relieve acute symptoms of COVID-19 infection.

Favorable Outcomes of Anticoagulation With Unfractioned Heparin in Sepsis-Induced Coagulopathy: A Retrospective Analysis of MIMIC-III Database

Backgrounds: Anticoagulation in sepsis-associated disseminated intravascular coagulation (DIC) remains uncertain. The aim of this study was to investigate whether unfractioned heparin (UFH) could improve clinical outcomes in patients with sepsis-induced coagulopathy (SIC).

Methods: Septic patients with SIC were identified from the Medical Information Mart for Intensive Care (MIMIC)-III database. Cox-proportional hazards model, logistic regression model and linear regression were used to assess the associations between UFH administration and 28-day mortality, hospital mortality, occurrence of bleeding complications and length of stay, respectively. Propensity score matching (PSM) analysis was used to match the imbalance between patients in the UFH group and the control group. Patients were further stratified according to SIC score and Simplified Acute Physiology Score II (SAPS II).

Results: A total of 1,820 septic patients with SIC were included in the data analysis. After PSM, 652 pairs of patients were matched between the patients in the UFH group and the control group. UFH was significantly associated with reduced 28-day mortality (HR, 0.323, 95% CI, 0.258–0.406; p < 0.001) and hospital mortality (HR, 0.380, 95% CI, 0.307–0.472; p < 0.001) without increasing the risks of intracranial hemorrhage (OR, 1.480, 95% CI, 0.955–2.294; p = 0.080) or gastrointestinal bleeding (OR, 1.094, 95% CI, 0.503–2.382; p = 0.820). For subgroup analysis, it didn't change the favorable results of UFH on mortality and UFH didn't increase the risk of hemorrhage in patients with severe disease.

Conclusions: The analysis of MIMIC-III database indicated that anticoagulant therapy with UFH may be associated with a survival benefit in patients with SIC.

Unfractionated heparin improves the clinical efficacy in adult sepsis patients: a systematic review and meta-analysis

Background

The anticoagulant treatment and clinical efficacy of heparin in sepsis remains controversial. We conducted a meta-analysis to estimate the clinical efficacy of unfractionated heparin (UFH) in adult septic patients.

Method

A systematic review of Medline, Cochrane Library, PubMed, Embase, WEIPU database, CNKI database, WANFANG database was performed from inception to January 2021. We included Randomized controlled trials (RCTs) and the main outcome was 28 d mortality. Data analysis was performed with Review Manager (RevMan) version 5.3 software. The meta-analysis included 2617 patients from 15 RCTs.

Results

Comparing to control group, UFH could reduce 28 d mortality (RR: 0.82; 95% CI: 0.72 to 0.94) especially for patient with Acute Physiology and Chronic Health Evaluation II (APACHE II) > 15, (RR: 0.83; 95% CI: 0.72 to 0.96). In UFH group, the platelet (PLT) (MD: 9.18; 95% CI: 0.68 to 17.68) was higher, the activated partial thromboplastin time (APTT) was shorter (MD: -8.01; 95% CI: − 13.84 to − 2.18) and the prothrombin time (PT) results (P > 0.05) failed to reach statistical significance. UFH decreased multiple organ dysfunction syndrome (MODS) incidence (RR: 0.61; 95% CI: 0.45 to 0.84), length of stay (LOS) in ICU (MD: -4.94; 95% CI: − 6.89 to − 2.99) and ventilation time (MD: -3.01; 95% CI: − 4.0 to − 2.02). And UFH had no adverse impact on bleeding (RR: 1.10; 95% CI: 0.54 to 2.23).

Conclusion

This meta-analysis suggests that UFH may reduce 28 d mortality and improve the clinical efficacy in sepsis patients without bleeding adverse effect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01545-w.

Signaling pathways and intervention therapies in sepsis

Sepsis is defined as life-threatening organ dysfunction caused by dysregulated host systemic inflammatory and immune response to infection. Over decades, advanced understanding of host-microorganism interaction has gradually unmasked the genuine nature of sepsis, guiding toward new definition and novel therapeutic approaches. Diverse clinical manifestations and outcomes among infectious patients have suggested the heterogeneity of immunopathology, while systemic inflammatory responses and deteriorating organ function observed in critically ill patients imply the extensively hyperactivated cascades by the host defense system. From focusing on microorganism pathogenicity, research interests have turned toward the molecular basis of host responses. Though progress has been made regarding recognition and management of clinical sepsis, incidence and mortality rate remain high. Furthermore, clinical trials of therapeutics have failed to obtain promising results. As far as we know, there was no systematic review addressing sepsis-related molecular signaling pathways and intervention therapy in literature. Increasing studies have succeeded to confirm novel functions of involved signaling pathways and comment on efficacy of intervention therapies amid sepsis. However, few of these studies attempt to elucidate the underlining mechanism in progression of sepsis, while other failed to integrate preliminary findings and describe in a broader view. This review focuses on the important signaling pathways, potential molecular mechanism, and pathway-associated therapy in sepsis. Host-derived molecules interacting with activated cells possess pivotal role for sepsis pathogenesis by dynamic regulation of signaling pathways. Cross-talk and functions of these molecules are also discussed in detail. Lastly, potential novel therapeutic strategies precisely targeting on signaling pathways and molecules are mentioned.

Endothelial dysfunction: a therapeutic target in bacterial sepsis?

INTRODUCTION

Endothelial cells maintain vascular integrity, tone, and patency and have important roles in hemostasis and inflammatory responses. Although some degree of endothelial dysfunction with increased vascular permeability may be necessary to control local infection, excessive dysfunction plays a central role in the pathogenesis of sepsis-related organ dysfunction and failure as it results in dysregulated inflammation, vascular leakage, and abnormal coagulation. The vascular endothelium has thus been proposed as a potential target for therapeutic intervention in patients with sepsis.

AREAS COVERED

Different mechanisms underlying sepsis-related dysfunction of the vascular endothelium are discussed, including glycocalyx shedding, nitrosative stress, and coagulation factors. Potential therapeutic implications of each mechanism are mentioned.

EXPERT OPINION

Multiple targets to protect or restore endothelial function have been suggested, but endothelium-driven treatments remain a future potential at present. As some endothelial dysfunction and permeability may be necessary to remove infection and repair damaged tissue, targeting the endothelium may be a particular challenge. Ideally, therapies should be guided by biomarkers related to that specific pathway to ensure they are given only to patients most likely to respond. This enrichment based on biological plausibility and theragnostics will increase the likelihood of a beneficial response in individual patients and enable more personalized treatment.

Endothelial Heparan Sulfate Proteoglycans in Sepsis: The Role of the Glycocalyx

There is increasing recognition of the importance of the endothelial glycocalyx and its in vivo manifestation, the endothelial surface layer, in vascular homeostasis. Heparan sulfate proteoglycans (HSPGs) are a major structural constituent of the endothelial glycocalyx and serve to regulate vascular permeability, microcirculatory tone, leukocyte and platelet adhesion, and hemostasis. During sepsis, endothelial HSPGs are shed through the induction of "sheddases" such as heparanase and matrix metalloproteinases, leading to loss of glycocalyx integrity and consequent vascular dysfunction. Less well recognized is that glycocalyx degradation releases HSPG fragments into the circulation, which can shape the systemic consequences of sepsis. In this review, we will discuss (1) the normal, homeostatic functions of HSPGs within the endothelial glycocalyx, (2) the pathological changes in HSPGs during sepsis and their consequences on the local vascular bed, and (3) the systemic consequences of HSPG degradation. In doing so, we will identify potential therapeutic targets to improve vascular function during sepsis as well as highlight key areas of uncertainty that require further mechanistic investigation.

The Role of Histones and Heparin in Sepsis: A Review

Septic shock with multiple organ failure is a devastating situation in clinical settings. Through the past decades, much progress has been made in the management of sepsis and its underlying pathogenesis, but a highly effective therapeutic has not been developed. Recently, macromolecules such as histones have been targeted in the treatment of sepsis. Histones primarily function as chromosomal organizers to pack DNA and regulate its transcription through epigenetic mechanisms. However, a growing body of research has shown that histone family members can also exert cellular toxicity once they relocate from the nucleus into the extracellular space. Heparin, a commonly used anti-coagulant, has been shown to possess life-saving capabilities for septic patients, but the potential interplay between heparin and extracellular histones has not been investigated. In this review, we summarize the pathogenic roles of extracellular histones and the therapeutic roles of heparin in the development and management of sepsis and septic shock.

Heparin prevents caspase-11-dependent septic lethality independent of anticoagulant properties

Heparin, a mammalian polysaccharide, is a widely used anticoagulant medicine to treat thrombotic disorders. It is also known to improve outcomes in sepsis, a leading cause of mortality resulted from infection-induced immune dysfunction. Whereas it is relatively clear how heparin exerts its anticoagulant effect, the immunomodulatory mechanisms enabled by heparin remain enigmatic. Here, we show that heparin prevented caspase-11-dependent immune responses and lethality in sepsis independent of its anticoagulant properties. Heparin or a chemically modified form of heparin without anticoagulant function inhibited the alarmin HMGB1-lipopolysaccharide (LPS) interaction and prevented the macrophage glycocalyx degradation by heparanase. These events blocked the cytosolic delivery of LPS in macrophages and the activation of caspase-11, a cytosolic LPS receptor that mediates lethality in sepsis. Survival was higher in septic patients treated with heparin than those without heparin treatment. The identification of this previously unrecognized heparin function establishes a link between innate immune responses and coagulation.

Thrombocytopenia-Associated Multiple Organ Failure

Thrombocytopenia-associated multiple organ failure is a clinical phenotype encompassing a spectrum of syndromes associated with disseminated microvascular thromboses. Autopsies performed in patients that died with thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, or disseminated intravascular coagulation reveal specific findings that can differentiate these 3 entities. Significant advancements have been made in our understanding of the pathologic mechanisms of these syndromes. Von Willebrand factor and ADAMTS-13 play a central role in thrombotic thrombocytopenic purpura. Shiga toxins and the complement pathway drive the hemolytic uremic syndrome pathology. Tissue factor activity is vital in the development of disseminated intravascular coagulation.

The role of type 1 interferons in coagulation induced by gram-negative bacteria

Bacterial infection not only stimulates innate immune responses but also activates coagulation cascades. Overactivation of the coagulation system in bacterial sepsis leads to disseminated intravascular coagulation (DIC), a life-threatening condition. However, the mechanisms by which bacterial infection activates the coagulation cascade are not fully understood. Here we show that type 1 interferons (IFNs), a widely expressed family of cytokines that orchestrate innate antiviral and antibacterial immunity, mediate bacterial infection-induced DIC by amplifying the release of high-mobility group box 1 (HMGB1) into the bloodstream. Inhibition of the expression of type 1 IFNs and disruption of their receptor IFN-α/βR or downstream effector (eg, HMGB1) uniformly decreased gram-negative bacteria-induced DIC. Mechanistically, extracellular HMGB1 markedly increased the procoagulant activity of tissue factor by promoting the externalization of phosphatidylserine to the outer cell surface, where phosphatidylserine assembles a complex of cofactor-proteases of the coagulation cascades. These findings not only provide novel insights into the link between innate immune responses and coagulation, but they also open a new avenue for developing novel therapeutic strategies to prevent DIC in sepsis.

Synthetic anticoagulant heparan sulfate attenuates liver ischemia reperfusion injury

Heparan sulfate (HS) is a sulfated glycosaminoglycan abundant on the cell surface and in the extracellular matrix and has several biological activities including anticoagulation and anti-inflammation. Liver ischemia reperfusion injury is associated with coagulation and inflammatory responses. Here, we synthesized HS oligosaccharides with defined sulfation patterns and show that synthetic anticoagulant HS oligosaccharides limit liver ischemia reperfusion injury in a mouse model. Using a small targeted HS library, we demonstrate that an oligosaccharide that possesses both anticoagulant activity and binding affinity to HMGB1, the inflammatory target, decreases injury greater than oligosaccharides that only bind to HMGB1 or only have anticoagulant activity. HS oligosaccharides may represent a potential new therapeutic option for decreasing liver damage resulting from ischemia reperfusion injury.

COVID-19-associated coagulopathy: An exploration of mechanisms

An ongoing global pandemic of viral pneumonia (coronavirus disease [COVID-19]), due to the virus SARS-CoV-2, has infected millions of people and remains a threat to many more. Most critically ill patients have respiratory failure and there is an international effort to understand mechanisms and predictors of disease severity. Coagulopathy, characterized by elevations in D-dimer and fibrin(ogen) degradation products (FDPs), is associated with critical illness and mortality in patients with COVID-19. Furthermore, increasing reports of microvascular and macrovascular thrombi suggest that hemostatic imbalances may contribute to the pathophysiology of SARS-CoV-2 infection. We review the laboratory and clinical findings of patients with COVID-19-associated coagulopathy, and prior studies of hemostasis in other viral infections and acute respiratory distress syndrome. We hypothesize that an imbalance between coagulation and inflammation may result in a hypercoagulable state. Although thrombosis initiated by the innate immune system is hypothesized to limit SARS-CoV-2 dissemination, aberrant activation of this system can cause endothelial injury resulting in loss of thromboprotective mechanisms, excess thrombin generation, and dysregulation of fibrinolysis and thrombosis. The role various components including neutrophils, neutrophil extracellular traps, activated platelets, microparticles, clotting factors, inflammatory cytokines, and complement play in this process remains an area of active investigation and ongoing clinical trials target these different pathways in COVID-19.

Enzymatic Synthesis of Chondroitin Sulfate E to Attenuate Bacteria Lipopolysaccharide-Induced Organ Damage

Chondroitin sulfate E (CS-E) is a sulfated polysaccharide that contains repeating disaccharides of 4,6-disulfated N-acetylgalactosamine and glucuronic acid residues. Here, we report the enzymatic synthesis of three homogeneous CS-E oligosaccharides, including CS-E heptasaccharide (CS-E 7-mer), CS-E tridecasaccharide (CS-E13-mer), and CS-E nonadecasaccharide (CS-E 19-mer). The anti-inflammatory effect of CS-E 19-mer was investigated in this study. CS-E 19-mer neutralizes the cytotoxic effect of histones in a cell-based assay and in mice. We also demonstrate that CS-E 19-mer treatment improves survival and protects against organ damage in a mouse model of endotoxemia induced by bacterial lipopolysaccharide (LPS). CS-E19-mer directly interacts with circulating histones in the plasma from LPS-challenged mice. CS-E 19-mer does not display anticoagulant activity nor react with heparin-induced thrombocytopenia antibodies isolated from patients. The successful synthesis of CS-E oligosaccharides provides structurally defined carbohydrates for advancing CS-E research and offers a potential therapeutic agent to treat life-threatening systemic inflammation.

Effects of endotoxin adsorber hemoperfusion on sublingual microcirculation in patients with septic shock: a randomized controlled trial

BACKGROUND

Endotoxins can induce an excessive inflammatory response and result in microcirculatory dysfunction. Polymyxin-B hemoperfusion (PMX-HP) has been recognized to effectively remove endotoxins in patients with sepsis and septic shock, and a rat sepsis model revealed that PMX-HP treatment can maintain a better microcirculation. The primary aim of this study was to investigate the effect of PMX-HP on microcirculation in patients with septic shock.

METHODS

Patients with septic shock were enrolled and randomized to control and PMX-HP groups. In the PMX-HP group, patients received the first session of PMX-HP in addition to conventional septic shock management within 24 h after the onset of septic shock; the second session of PMX-HP was provided after another 24 h as needed.

RESULTS

Overall, 28 patients finished the trial and were analyzed. The mean arterial pressure and norepinephrine infusion dose did not differ significantly between the control and PMX-HP groups after PMX-HP treatment. At 48 h after enrollment, total vessel density (TVD) and perfused vessel density (PVD) were higher in the PMX-HP group than in the control group [TVD 24.2 (22.1-24.9) vs. 21.1 (19.9-22.9) mm/mm2; p = 0.007; PVD 22.9 (20.9-24.9) vs. 20.0 (18.9-21.6) mm/mm2, p = 0.008].

CONCLUSIONS

This preliminary study observed that PMX-HP treatment improved microcirculation but not clinical outcomes in patients with septic shock at a low risk of mortality. Nevertheless, larger multicenter trials are needed to confirm the effect of PMX-HP treatment on microcirculation in patients with septic shock at intermediate- and high-risk of mortality. Trial registration ClinicalTrials.gov protocol registration ID: NCT01756755. Date of registration: December 27, 2012. First enrollment: October 6, 2013. https://clinicaltrials.gov/ct2/show/NCT01756755.