Extracellular DNA traps promote thrombosis. Proc Natl Acad Sci U S A. 2010;107:15880-15885. [PMID: 20798043 DOI: 10.1073/pnas.1005743107]

Cell-free DNA predicts all-cause mortality of sepsis-induced acute kidney injury

Background Sepsis-induced acute kidney injury (S-AKI) is a common complication in critically ill patients. Therefore, reliable biomarkers for predicting S-AKI outcomes are necessary. Serum cell-free DNA (cfDNA) is a circulating extracellular DNA fragment used as a noninvasive screening tool for many diseases, including sepsis. This study aimed to investigate the prognostic value of cfDNA in S-AKI patients and its relationship with some other parameters.Methods A total of 89 S-AKI patients admitted to the intensive care unit (ICU) from June 2021 to December 2021 were enrolled in this study. The patients were categorized into the low cfDNA group (< 855 ng/ml) and high cfDNA group (≥ 855 ng/ml) and were followed up for three months. CfDNA was extracted from serum and quantified using Quant-iT PicoGreen dsDNA Reagent.Results Overall survival was significantly lower in the high cfDNA group than in the low cfDNA group (Log-Rank p = 0.012). Univariate Cox proportional hazard model showed that cfDNA was significantly associated with all-cause mortality (HR [hazard ratio] 2.505, 95% CI [95% confidence interval] 1.184-5.298, p = 0.016). Also, serum cfDNA was a significant risk factor for all-cause mortality after adjusting for covariates (HR 2.191, 95% CI 1.017-4.721, p = 0.045). Moreover, cfDNA was positively correlated with several baseline parameters, including serum creatine, aspartate aminotransferase, alanine aminotransferase, prothrombin time, and International Normalized Ratio.Conclusion High serum cfDNA level is associated with higher mortality among the S-AKI population, indicating that cfDNA is a valuable biomarker for S-AKI prognosis.

Relationship between thrombocytopenia and prognosis in children with septic shock: a retrospective cohort study

Septic shock is a life-threatening disease worldwide often associated with thrombocytopenia. Platelets play a crucial role in bridging the gap between immunity, coagulation, and endothelial cell activation, potentially influencing the course of the disease. However, there are few studies specifically evaluating the impact of thrombocytopenia on the prognosis of pediatric patients. Therefore, the study investigates effects of early thrombocytopenia in the prognosis of children with septic shock. Pediatric patients with septic shock from 2015 to 2022 were included monocentrically. Thrombocytopenia was defined as a platelet count of <100 × 109/L during the first 24 hours of septic shock onset. The primary outcome was the 28-day mortality. Propensity score matching was used to pair patients with different platelet counts on admission but comparable disease severity. A total of 419 pediatric patients were included in the analysis. Patients with thrombocytopenia had higher 28-day mortality (55.5% vs. 38.7%, p = .005) compared to patients with no thrombocytopenia. Thrombocytopenia was associated with reduced 28-PICU free days (median value, 0 vs. 13 days, p = .003) and 28-ventilator-free (median value, 0 vs. 19 days, p = .001) days. Among thrombocytopenia patients, those with platelet count ≤50 × 109/L had a higher 28-day mortality rate (63.6% vs. 45%, p = .02). Multiple logistic regression showed that elevated lactate (adjusted odds ratio (OR) = 1.11; 95% confidence interval (CI): 1.04-1.17; P <0.001) and white blood cell (WBC) count (OR = 0.97; 95% CI: 0.95-0.99; p = .003) were independent risk factors for the development of thrombocytopenia. Thrombocytopenia group had increased bleeding events, blood product transfusions, and development of organ failure. In Kaplan-Meier survival estimates, survival probabilities at 28 days were greater in patients without thrombocytopenia (p value from the log-rank test, p = .004). There were no significant differences in the type of pathogenic microorganisms and the site of infection between patients with and without thrombocytopenia. In conclusion, thrombocytopenia within 24 hours of shock onset is associated with an increased risk of 28-day mortality in pediatric patients with septic shock.

Identification of diagnostic signature and immune microenvironment subtypes of venous thromboembolism

The close link between immune and pathogenesis of venous thromboembolism (VTE) has been recognized, but not fully elucidated. The current study was designed to identify immune microenvironment related signature and subtypes using explainable machine learning in VTE. We first observed an alteration of immune microenvironment in VTE patients and identified eight key immune cells involved in VTE. Then PTPN6, ITGB2, CR2, FPR2, MMP9 and ISG15 were determined as key immune microenvironment-related genes, which could divide VTE patients into two subtypes with different immune and metabolic characteristics. Also, we found that prunetin and torin-2 may be most promising to treat VTE patients in Cluster 1 and 2, respectively. By comparing six machine learning models in both training and external validation sets, XGboost was identified as the best one to predict the risk of VTE, followed by the interpretation of each immune microenvironment-related gene contributing to the model. Moreover, CR2 and FPR2 had high accuracy in distinguishing VTE and control, which may act as diagnostic biomarkers of VTE, and their expressions were validated by qPCR. Collectively, immune microenvironment related PTPN6, ITGB2, CR2, FPR2, MMP9 and ISG15 are key genes involved in the pathogenesis of VTE. The VTE risk prediction model and immune microenvironment subtypes based on those genes might benefit prevention, diagnosis, and the individualized treatment strategy in clinical practice of VTE.

Association between lower neutrophil-to-albumin ratio and early neurological improvement in patients with acute cerebral infarction after intravenous thrombolysis

Elevated neutrophil counts and decreased albumin levels have been linked to an unfavorable prognosis in acute cerebral infarction (ACI). The objective of this study is to explore the correlation between the neutrophil-to-albumin ratio (NAR) and the early neurological improvement (ENI) of ACI patients following intravenous thrombolysis (IVT). ACI patients who underwent IVT between June 2019 and June 2023 were enrolled. The severity of ACI was assessed using the National Institutes of Health Stroke Scale (NIHSS). ENI was defined as a reduction in NIHSS score of ≥ 4 or complete resolution of neurological deficit within 24 h after IVT. Propensity score match (PSM) and logistic regression analysis were used to explore the correlation between these variables and the early neurological outcomes of patients. A total of 545 ACI patients were included, with 253 (46.4 %) experiencing ENI. Among the 193 pairs of patients after PSM, there was a significant association between NAR and ENI (OR, 0.89; 95 % CI, 0.85-0.94; p < 0.001). The restricted cubic splines analysis revealed a significant nonlinear correlation between NAR and ENI (p for nonlinear = 0.0004; p for overall = 0.0002). The optimal cutoff for predicting ENI was determined as a NAR level of 10.20, with sensitivity and specificity values of 73.6 % and 60.9 %. NAR levels are associated with ENI in ACI patients after IVT. The decreased levels of NAR indicate an increased likelihood of post-thrombolysis ENI in ACI patients.

Peptidylarginine deiminase (PAD): A promising target for chronic diseases treatment

In 1958, the presence of citrulline in the structure of the proteins was discovered for the first time. Several years later they found that Arginine converted to citrulline during a post-translational modification process by PAD enzyme. Each PAD is expressed in a certain tissue developing a series of diseases such as inflammation and cancers. Among these, PAD2 and PAD4 play a role in the development of rheumatoid arthritis (RA) by producing citrullinated autoantigens and increasing the production of inflammatory cytokines. PAD4 is also associated with the formation of NET structures and thrombosis. In the crystallographic structure, PAD has several calcium binding sites, and the active site of the enzyme consists of different amino acids. Various PAD inhibitors have been developed divided into pan-PAD and selective PAD inhibitors. F-amidine, Cl-amidine, and BB-Cl-amidine are some of pan-PAD inhibitors. AFM-30a and JBI589 are selective for PAD2 and PAD4, respectively. There is a need to evaluate the effectiveness of existing inhibitors more accurately in the coming years, as well as design and production of novel inhibitors targeting highly specific isoforms.

Neutrophil extracellular traps: Potential targets for the treatment of rheumatoid arthritis with traditional Chinese medicine and natural products

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease. Abnormal formation of neutrophil extracellular traps (NETs) at the synovial membrane leads to the release of many inflammatory cytokines, including IL-1β, IL-6, and TNF-α. Elastase, histone H3, and myeloperoxidase, which are carried by NETs, damage the soft tissues of the joints and aggravate the progression of RA. The balance of NET formation coordinates the pro-inflammatory and anti-inflammatory effects and plays a key role in the development of RA. Therefore, when NETs are used as effector targets, highly targeted drugs with fewer side effects can be developed to treat RA without damaging the host immune system. Currently, an increasing number of studies have shown that traditional Chinese medicines and natural products can regulate the formation of NETs through multiple pathways to counteract RA, which shows great potential for the treatment of RA and has a promising future for clinical application. In this article, we review the latest biological progress in understanding NET formation, the mechanism of NETs in RA, and the potential targets or pathways related to the modulation of NET formation by Chinese medicines and natural products. This review provides a relevant basis for the use of Chinese medicines and natural products as natural adjuvants in the treatment of RA.

Atorvastatin combined with imipenem alleviates lung injury in sepsis by inhibiting neutrophil extracellular trap formation via the ERK/NOX2 signaling pathway

Sepsis is a systemic inflammatory response syndrome caused by the invasion of pathogenic microorganisms. Despite major advances in diagnosis and technology, morbidity and mortality remain high. The level of neutrophil extracellular traps (NETs) is closely associated with the progression and prognosis of sepsis, suggesting the regulation of NET formation as a new strategy in sepsis treatment. Owing to its pleiotropic effects, atorvastatin, a clinical lipid-lowering drug, affects various aspects of sepsis-related inflammation and immune responses. To align closely with clinical practice, we combined it with imipenem for the treatment of sepsis. In this study, we used a cecum ligation and puncture-induced lung injury mouse model and employed techniques including western blot, immunofluorescence, and enzyme-linked immunosorbent assay to measure the levels of NETs and other sepsis-related lung injury indicators. Our findings indicate that atorvastatin effectively inhibited the formation of NETs. When combined with imipenem, it significantly alleviated lung injury, reduced systemic inflammation, and improved the 7-day survival rate of septic mice. Additionally, we explored the inhibitory mechanism of atorvastatin on NET formation in vitro, revealing its potential action through the ERK/NOX2 pathway. Therefore, atorvastatin is a potential immunomodulatory agent that may offer new treatment strategies for patients with sepsis in clinical settings.

Assessment of associations between neutrophil extracellular trap biomarkers in blood and thrombi in acute ischemic stroke patients

Inflammation including immunothrombosis by neutrophil extracellular traps (NETs) has important implications in acute ischemic stroke and can affect reperfusion status, susceptibility to stroke associated infections (SAI) as well as functional clinical outcome. NETs were shown to be prevalent in stroke thrombi and NET associated markers were found in stroke patients' blood. However, little is known whether blood derived NET markers reflect the amount of NETs in thrombi. Conclusions from blood derived markers to thrombus composition might open avenues for novel strategies in diagnostic and therapeutic approaches. We prospectively recruited 166 patients with acute ischemic stroke undergoing mechanical thrombectomy between March 2018 and May 2021. Available thrombi (n = 106) were stained for NET markers DNA-histone-1 complexes and myeloperoxidase (MPO). Cell free DNA (cfDNA), deoxyribonuclease (DNase) activity, MPO-histone complexes and a cytokine-panel were measured before thrombectomy and after seven days. Clinical data, including stroke etiology, reperfusion status, SAI and functional outcome after rehabilitation, were collected of all patients. NET markers were present in all thrombi. At onset the median concentration of cfDNA in blood was 0.19 µg/ml increasing to 0.30 µg/ml at 7 days. Median DNase activity at onset was 4.33 pmol/min/ml increasing to 4.96 pmol/min/ml at 7 days. Within thrombi DNA-histone-1 complexes and MPO correlated with each other (ρ = 0.792; p < 0.001). Moreover, our study provides evidence for an association between the amount of NETs and endogenous DNase activity in blood with amounts of NETs in cerebral thrombi. However, these associations need to be confirmed in larger cohorts, to investigate the potential clinical implications for individualized therapeutic and diagnostic approaches in acute ischemic stroke.

ADAMTS13 or Caplacizumab Reduces the Accumulation of Neutrophil Extracellular Traps and Thrombus in Whole Blood of COVID-19 Patients under Flow

BACKGROUND

 Neutrophil NETosis and neutrophil extracellular traps (NETs) play a critical role in pathogenesis of coronavirus disease 2019 (COVID-19)-associated thrombosis. However, the extents and reserve of NETosis, and potential of thrombus formation under shear in whole blood of patients with COVID-19 are not fully elucidated. Neither has the role of recombinant ADAMTS13 or caplacizumab on the accumulation of NETs and thrombus in COVID-19 patients' whole blood under shear been investigated.

METHODS

 Flow cytometry and microfluidic assay, as well as immunoassays, were employed for the study.

RESULTS

 We demonstrated that the percentage of H3Cit + MPO+ neutrophils, indicative of NETosis, was dramatically increased in patients with severe but not critical COVID-19 compared with that in asymptomatic or mild disease controls. Upon stimulation with poly [I:C], a double strain DNA mimicking viral infection, or bacterial shigatoxin-2, the percentage of H3Cit + MPO+ neutrophils was not significantly increased in the whole blood of severe and critical COVID-19 patients compared with that of asymptomatic controls, suggesting the reduction in NETosis reserve in these patients. Microfluidic assay demonstrated that the accumulation of NETs and thrombus was significantly enhanced in the whole blood of severe/critical COVID-19 patients compared with that of asymptomatic controls. Like DNase I, recombinant ADAMTS13 or caplacizumab dramatically reduced the NETs accumulation and thrombus formation under arterial shear.

CONCLUSION

 Significantly increased neutrophil NETosis, reduced NETosis reserve, and enhanced thrombus formation under arterial shear may play a crucial role in the pathogenesis of COVID-19-associated coagulopathy. Recombinant ADAMTS13 or caplacizumab may be explored for the treatment of COVID-19-associated thrombosis.

Hot under the clot: venous thrombogenesis is an inflammatory process

ABSTRACT

Venous thrombosis (VT) is a serious medical condition in which a blood clot forms in deep veins, often causing limb swelling and pain. Current antithrombotic therapies carry significant bleeding risks resulting from targeting essential coagulation factors. Recent advances in this field have revealed that the cross talk between the innate immune system and coagulation cascade is a key driver of VT pathogenesis, offering new opportunities for potential therapeutic interventions without inducing bleeding complications. This review summarizes and discusses recent evidence from preclinical models on the role of inflammation in VT development. We highlight the major mechanisms by which endothelial cell activation, Weibel-Palade body release, hypoxia, reactive oxygen species, inflammasome, neutrophil extracellular traps, and other immune factors cooperate to initiate and propagate VT. We also review emerging clinical data describing anti-inflammatory approaches as adjuncts to anticoagulation in VT treatment. Finally, we identify key knowledge gaps and future directions that could maximize the benefit of anti-inflammatory therapies in VT. Identifying and targeting the inflammatory factors driving VT, either at the endothelial cell level or within the clot, may pave the way for new therapeutic possibilities for improving VT treatment and reducing thromboembolic complications without increasing bleeding risk.

Intraluminal release of citrullinated histone 3 from various cellular origins coincides with microvascular thrombosis in burn wounds

Loss of perfusion in the burn wound might cause wound deepening and impaired healing. We previously showed persistent microvascular thrombosis coinciding with intraluminal neutrophils extracellular traps in human burned skin. This study investigates the presence of intraluminal citrullinated histone 3 (H3cit) from different cellular origins (neutrophils, monocytes, and lymphocytes) in relation to microvascular thrombosis of burn wounds. Eschar was obtained from burn patients (n = 18) 6-40 days postburn with a mean total burned body surface area of 23%. Microvascular presence of tissue factor (TF), factor XII (FXII) and thrombi was assessed by immunohistochemistry. Intramicrovascular cell death was analyzed via immunofluorescent microscopy, combining antibodies for neutrophils (MPO), monocytes (CD14), and lymphocytes (CD45) with endothelial cell markers CD31 and H3cit. Significantly increased microvascular expression of TF, FXII, and thrombi (CD31+) was found in all eschar samples compared with control uninjured skin. Release of H3cit from different cellular origins was observed in the lumen of the dermal microvasculature in the eschar tissue 7-40 days postburn, with release from neutrophilic origin being 2.7 times more abundant. Intraluminal presence of extracellular H3cit colocalizing with either MPO, CD14, or CD45 is correlated to increased microvascular thrombosis in eschar of burn patients.

Neutrophil extracellular traps in cancer

Neutrophil extracellular traps (NETs), which consist of chromatin DNA studded with granule proteins, are released by neutrophils in response to both infectious and sterile inflammation. Beyond the canonical role in defense against pathogens, the extrusion of NETs also contributes to the initiation, metastasis, and therapeutic response of malignant diseases. Recently, NETs have been implicated in the development and therapeutic responses of various types of tumors. Although extensive work regarding inflammation in tumors has been reported, a comprehensive summary of how these web-like extracellular structures initiate and propagate tumor progression under the specific microenvironment is lacking. In this review, we demonstrate the initiators and related signaling pathways that trigger NETs formation in cancers. Additionally, this review will outline the current molecular mechanisms and regulatory networks of NETs during dormant cancer cells awakening, circulating tumor cells (CTCs) extravasation, and metastatic recurrence of cancer. This is followed by a perspective on the current and potential clinical potential of NETs as therapeutic targets in the treatment of both local and metastatic disease, including the improvement of the efficacy of existing therapies.

Neutrophil extracellular traps mediate neuro-immunothrombosis

Neutrophil extracellular traps are primarily composed of DNA and histones and are released by neutrophils to promote inflammation and thrombosis when stimulated by various inflammatory reactions. Neutrophil extracellular trap formation occurs through lytic and non-lytic pathways that can be further classified by formation mechanisms. Histones, von Willebrand factor, fibrin, and many other factors participate in the interplay between inflammation and thrombosis. Neuro-immunothrombosis summarizes the intricate interplay between inflammation and thrombosis during neural development and the pathogenesis of neurological diseases, providing cutting-edge insights into post-neurotrauma thrombotic events. The blood-brain barrier defends the brain and spinal cord against external assaults, and neutrophil extracellular trap involvement in blood-brain barrier disruption and immunothrombosis contributes substantially to secondary injuries in neurological diseases. Further research is needed to understand how neutrophil extracellular traps promote blood-brain barrier disruption and immunothrombosis, but recent studies have demonstrated that neutrophil extracellular traps play a crucial role in immunothrombosis, and identified modulators of neuro-immunothrombosis. However, these neurological diseases occur in blood vessels, and the mechanisms are unclear by which neutrophil extracellular traps penetrate the blood-brain barrier to participate in immunothrombosis in traumatic brain injury. This review discusses the role of neutrophil extracellular traps in neuro-immunothrombosis and explores potential therapeutic interventions to modulate neutrophil extracellular traps that may reduce immunothrombosis and improve traumatic brain injury outcomes.

The convergent model of coagulation

It is increasingly apparent that the pathologic interplay between coagulation and innate immunity, ie, immunothrombosis, forms the common basis of many challenges across the boundaries of specialized medicine and cannot be fully explained by the conventional concepts of cascade and cell-based coagulation. To improve our understanding of coagulation, we propose a model of coagulation that converges with inflammation and innate immune activation as a unified response toward vascular injury. Evolutionarily integral to the convergent response are damage-associated molecular patterns, which are released as a consequence of injury. Damage-associated molecular patterns facilitate diverse interactions within and between systems, not only to complement and reinforce cell-based clot formation but also to steer the response toward clot resolution and wound healing. By extending coagulation beyond its current boundaries, the convergent model aims to deliver novel diagnostics and therapeutics for contemporary and unexpected challenges across medicine, as exposed by COVID-19 and vaccine-induced immune thrombotic thrombocytopenia.

Bibliometric insights into the inflammation and mitochondrial stress in ischemic stroke

BACKGROUND

Research in the areas of inflammation and mitochondrial stress in ischemic stroke is rapidly expanding, but a comprehensive overview that integrates bibliometric trends with an in-depth review of molecular mechanisms is lacking.

OBJECTIVE

To map the evolving landscape of research using bibliometric analysis and to detail the molecular mechanisms that underpin these trends, emphasizing their implications in ischemic stroke.

METHODS

We conducted a bibliometric analysis to identify key trends, top contributors, and focal research themes. In addition, we review recent research advances in mitochondrial stress and inflammation in ischemic stroke to gain a detailed understanding of the pathophysiological processes involved.

CONCLUSION

Our integrative approach not only highlights the growing research interest and collaborations but also provides a detailed exploration of the molecular mechanisms that are central to the pathology of ischemic stroke. This synthesis offers valuable insights for researchers and paves the way for targeted therapeutic interventions.

SIRT1-Mediated HMGB1 Deacetylation Suppresses Neutrophil Extracellular Traps Related to Blood-Brain Barrier Impairment After Cerebral Venous Thrombosis

Cerebral venous thrombosis (CVT) is a neurovascular disease with recently increasing incidence. Aseptic inflammatory responses play an important role in the pathology of CVT. Recent studies report that neutrophil extracellular traps (NETs) are major triggers of thrombosis and inflammation in stroke, but their effect on brain injury in CVT requires further validation. In this study, two CVT animal models were used to simulate superior sagittal sinus thrombosis and cortical vein thrombosis. The effects of brain tissue infiltration of NETs and the molecular mechanisms associated with NET formation were deeply explored in combination with proteomics, histology, and serology. The results showed that the cortical vein thrombosis model could be combined with more severe blood-brain barrier (BBB) disruption and showed more severe cerebral hemorrhage. Decreased Sirtuin 1 (SIRT1) expression promotes high mobility group box 1 (HMGB1) acetylation, causing increased cytosolic translocation and extracellular release, and HMGB1 can promote NET formation and recruitment. In addition, corticocerebral accumulation of NETs contributes to BBB damage. This establishes a vicious cycle between BBB damage and NET accumulation. SIRT1 mediated-HMGB1 deacetylation may play a critical role in attenuating BBB damage following CVT. This study employed a combined validation using models of venous sinus thrombosis and cortical vein thrombosis to investigate the deacetylation role of SIRT1, aiming to offer new insights into the pathological mechanisms of brain injury following CVT.

Comprehensive macro and micro views on immune cells in ischemic heart disease

Ischemic heart disease (IHD) is a prevalent cardiovascular condition that remains the primary cause of death due to its adverse ventricular remodelling and pathological changes in end-stage heart failure. As a complex pathologic condition, it involves intricate regulatory processes at the cellular and molecular levels. The immune system and cardiovascular system are closely interconnected, with immune cells playing a crucial role in maintaining cardiac health and influencing disease progression. Consequently, alterations in the cardiac microenvironment are influenced and controlled by various immune cells, such as macrophages, neutrophils, dendritic cells, eosinophils, and T-lymphocytes, along with the cytokines they produce. Furthermore, studies have revealed that Gata6+ pericardial cavity macrophages play a key role in regulating immune cell migration and subsequent myocardial tissue repair post IHD onset. This review outlines the role of immune cells in orchestrating inflammatory responses and facilitating myocardial repair following IHD, considering both macro and micro views. It also discusses innovative immune cell-based therapeutic strategies, offering new insights for further research on the pathophysiology of ischemic heart disease and immune cell-targeted therapy for IHD.

IL-1 signaling pathway, an important target for inflammation surrounding in myocardial infarction

Acute myocardial infarction is an important cardiovascular disease worldwide. Although the mortality rate of myocardial infarction (MI) has improved dramatically in recent years due to timely treatment, adverse remodeling of the left ventricle continues to affect cardiac function. Various immune cells are involved in this process to induce inflammation and amplification. The infiltration of inflammatory cells in the infarcted myocardium is induced by various cytokines and chemokines, and the recruitment of leukocytes further amplifies the inflammatory response. As an increasing number of clinical anti-inflammatory therapies have achieved significant success in recent years, treating myocardial infarction by targeting inflammation may become a novel therapeutic option. In particular, successful clinical trials of canakinumab have demonstrated the important role of the inflammatory factor interleukin-1 (IL-1) in atherosclerosis. Targeted IL-1 therapy may decrease inflammation levels and improve cardiac function in patients after myocardial infarction. This article reviews the complex series of responses after myocardial infarction, including the involvement of inflammatory cells and the role of cytokines and chemokines, focusing on the progression of the IL-1 family in myocardial infarction as well as the performance of current targeted therapy drugs in experiments.

Exploring bradykinin: A common mediator in the pathophysiology of sepsis and atherosclerotic cardiovascular disease

Sepsis and atherosclerotic cardiovascular disease (ASCVD) are major health challenges involving complex processes like inflammation, renin-angiotensin system (RAS) dysregulation, and thrombosis. Despite distinct clinical symptoms, both conditions share mechanisms mediated by bradykinin. This review explores bradykinin's role in inflammation, RAS modulation, and thrombosis in sepsis and ASCVD. In sepsis, variable kininogen-bradykinin levels may correlate with disease severity and progression, though the effect of bradykinin receptor modulation on inflammation remains uncertain. RAS activation is present in both diseases, with sepsis showing variable or low levels of Ang II, ACE, and ACE2, while ASCVD consistently exhibits elevated levels. Bradykinin may act as a mediator for ACE2 and AT2 receptor effects in RAS regulation. It may influence clotting and fibrinolysis in sepsis-associated coagulopathy, but evidence for an antithrombotic effect in ASCVD is insufficient. Understanding bradykinin's role in these shared pathologies could guide therapeutic and monitoring strategies and inform future research.

Development of a Clonal and High-Yield Mammalian Cell Line for the Manufacturing of a Hyperactive Human DNase I with Extended Plasma Half-Life Using PASylation® Technology

Cumulative evidence from several pre-clinical studies suggests that restoration of plasma DNase activity in a thrombo-inflammatory state may improve clinical outcomes. Following injury, hyperactivated immune cells release large amounts of granular proteins together with DNA, which often accumulate in the surrounding environment in so-called neutrophil extracellular traps (NETs). Degradation of excess NETs by systemic DNase administration offers a promising therapeutic approach to ameliorate inflammation and dissolve intravascular clots. In order to expand the therapeutic utility of human DNase I, a variant of the enzyme was developed that has both a prolonged systemic half-life and a higher catalytic activity compared to Dornase alfa (Pulmozyme®), the recombinant form of DNase I approved for inhaled therapy of cystic fibrosis. The hyperactive enzyme was "PASylated" by genetic fusion with a strongly hydrophilic and biodegradable PAS-polypeptide to increase its hydrodynamic volume and retard kidney filtration. A stable TurboCell™ CHO-K1-based cell line was generated which is suitable for the future production of PASylated DNase I according to good manufacturing practice (GMP). Furthermore, a robust bioprocess strategy was devised and an effective downstream process was developed. The final protein product is characterized by excellent purity, favorable physicochemical properties, a 14-fold higher DNA-degrading activity than Dornase alfa and a sustained pharmacokinetic profile, with a 22-fold slower clearance in rats.

Novel Diagnostic Biomarkers Related to Necroptosis and Immune Infiltration in Coronary Heart Disease

Purpose

Necroptosis, a monitored form of inflammatory cell death, contributes to coronary heart disease (CHD) progression. This study examined the potential of using necroptosis genes as diagnostic markers for CHD and sought to elucidate the underlying roles.

Methods

Through bioinformatic analysis of GSE20680 and GSE20681, we first identified the differentially expressed genes (DEGs) related to necroptosis in CHD. Hub genes were identified using least absolute shrinkage and selection operator (LASSO) regression and random forest analysis after studying immune infiltration and transcription factor-miRNA interaction networks according to the DEGs. Quantitative polymerase chain reaction and immunohistochemistry were used to further investigate hub gene expression in vivo, for which a diagnostic model was constructed and the predictive efficacy was validated. Finally, the CHD group was categorized into high- and low-score groups in accordance with the single-sample gene set enrichment analysis (ssGSEA) score of the necroptosis genes. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, GSEA, and further immune infiltration analyses were performed on the two groups to explore the possible roles of hub genes.

Results

Based on the results of the LASSO regression and random forest analyses, four genes were used to construct a diagnostic model to establish a nomogram. Additionally, an extensive analysis of all seventeen necroptosis genes revealed notable distinctions in expression between high-risk and low-risk groups. Evaluation of immune infiltration revealed that neutrophils, monocytes, B cells, and activated dendritic cells were highly distributed in the peripheral blood of patients with CHD. Specifically, the high CHD score group exhibited greater neutrophil and monocyte infiltration. Conversely, the high-score group showed lower infiltration of M0 and M2 macrophages, CD8+ T, plasma, and resting mast cells.

Conclusion

TLR3, MLKL, HMGB1, and NDRG2 may be prospective biomarkers for CHD diagnosis. These findings offer plausible explanations for the role of necroptosis in CHD progression through immune infiltration and inflammatory response.

Ischaemic Stroke, Thromboembolism and Clot Structure

Ischaemic stroke is a major cause of morbidity and mortality worldwide. Blood clotting and thromboembolism play a central role in the pathogenesis of ischaemic stroke. An increasing number of recent studies indicate changes in blood clot structure and composition in patients with ischaemic stroke. In this review, we aim to summarise and discuss clot structure, function and composition in ischaemic stroke, including its relationships with clinical diagnosis and treatment options such as thrombolysis and thrombectomy. Studies are summarised in which clot structure and composition is analysed both in vitro from patients' plasma samples and ex vivo in thrombi obtained through interventional catheter-mediated thrombectomy. Mechanisms that drive clot composition and architecture such as neutrophil extracellular traps and clot contraction are also discussed. We find that, while in vitro clot structure in plasma samples from ischaemic stroke patients are consistently altered, showing denser clots that are more resistant to fibrinolysis, current data on the composition and architecture of ex vivo clots obtained by thrombectomy are more variable. With the potential of advances in technologies underpinning both the imaging and retrieving of clots, we expect that future studies in this area will generate new data that is of interest for the diagnosis, optimal treatment strategies and clinical management of patients with ischaemic stroke.

Acute Ischemic Stroke Thrombus Composition

Ischemic stroke is caused by a thrombus blocking one or multiple arteries in the brain, resulting in irreversible damage in the associated brain tissue. The aim of therapy is to restore the blood flow as fast as possible. Two recanalization strategies are currently available: pharmacological thrombolysis using recombinant tissue plasminogen activator (rt-PA) and mechanical removal of the thrombus. Despite recent advancements, achieving efficient recanalization remains a challenge. The precise causes of therapy failure are not fully understood but thrombus composition is likely a key factor in successful recanalization. This review explores acute ischemic stroke thrombus composition, its recently identified components, and how it affects stroke treatment. It also discusses how new insights could enhance current recanalization strategies for ischemic stroke patients.

Neutrophil extracellular traps promote immune escape in hepatocellular carcinoma by up-regulating CD73 through Notch2

Immune escape is the main reason that immunotherapy is ineffective in hepatocellular carcinoma (HCC). Here, this study illustrates a pathway mediated by neutrophil extracellular traps (NETs) that can promote immune escape of HCC. Mechanistically, we demonstrated that NETs up-regulated CD73 expression through activating Notch2 mediated nuclear factor kappa B (NF-κB) pathway, promoting regulatory T cells (Tregs) infiltration to mediate immune escape of HCC. In addition, we found the similar results in mouse HCC models by hydrodynamic plasmid transfection. The treatment of deoxyribonuclease I (DNase I) could inhibit the action of NETs and improve the therapeutic effect of anti-programmed cell death protein 1 (PD-1). In summary, our results revealed that targeting of NETs was a promising treatment to improve the therapeutic effect of anti-PD-1.

The role of P-selectin/PSGL-1 in regulating NETs as a novel mechanism in cerebral ischemic injury

In recent years, substantial advancements have been made in understanding the pathophysiology of ischemic stroke. Despite these developments, therapeutic options for cerebral ischemia remain limited due to stringent time windows and various contraindications. Consequently, there has been a concentrated effort to elucidate the underlying mechanisms of cerebral ischemic injury. Emerging research indicates that neutrophil extracellular traps (NETs) exacerbate inflammation and damage in ischemic brain tissue, contributing to neuronal cell death. The inhibition of NETs has shown potential in preventing thrombosis and the infiltration of immune cells. Central to the formation of NETs are P-selectin and its ligand, P-selectin glycoprotein ligand-1 (PSGL-1), which represent promising therapeutic targets. This review explores the detrimental impact of P-selectin, PSGL-1, and NETs on cerebral ischemia. Additionally, it delineates the processes by which P-selectin and PSGL-1 stimulate NETs production and provides evidence that blocking these molecules reduces NETs formation. This novel insight highlights a potential therapeutic avenue that warrants further investigation by researchers in the field.

Neutrophil extracellular traps-inspired DNA hydrogel for wound hemostatic adjuvant

Severe traumatic bleeding may lead to extremely high mortality rates, and early intervention to stop bleeding plays as a critical role in saving lives. However, rapid hemostasis in deep non-compressible trauma using a highly water-absorbent hydrogel, combined with strong tissue adhesion and bionic procoagulant mechanism, remains a challenge. In this study, a DNA hydrogel (DNAgel) network composed of natural nucleic acids with rapid water absorption, high swelling and instant tissue adhesion is reported, like a band-aid to physically stop bleeding. The excellent swelling behavior and robust mechanical performance, meanwhile, enable the DNAgel band-aid to fill the defect cavity and exert pressure on the bleeding vessels, thereby achieving compression hemostasis for deep tissue bleeding sites. The neutrophil extracellular traps (NETs)-inspired DNAgel network also acts as an artificial DNA scaffold for erythrocytes to adhere and aggregate, and activates platelets, promoting coagulation cascade in a bionic way. The DNAgel achieves lower blood loss than commercial gelatin sponge (GS) in male rat trauma models. In vivo evaluation in a full-thickness skin incision model also demonstrates the ability of DNAgel for promoting wound healing. Overall, the DNAgel band-aid with great hemostatic capacity is a promising candidate for rapid hemostasis and wound healing.

Biomarkers of bleeding and venous thromboembolism in patients with acute leukemia

BACKGROUND

Coagulopathy and associated bleeding and deep vein thrombosis (DVT) are major causes of morbidity and mortality in patients with acute leukemia. The underlying mechanisms of these complications have not been fully elucidated.

OBJECTIVES

To evaluate the associations between biomarker levels and bleeding and DVT in acute leukemia patients.

METHODS

We examined plasma levels of activators, inhibitors, and biomarkers of the coagulation and fibrinolytic pathways in patients aged ≥18 years with newly diagnosed acute leukemia compared with those of normal controls. Multivariable regression models were used to examine the association of biomarkers with bleeding and DVT in acute leukemia patients. The study included 358 patients with acute leukemia (29 with acute promyelocytic leukemia [APL], 253 with non-APL acute myeloid leukemia, and 76 with acute lymphoblastic leukemia) and 30 normal controls.

RESULTS

Patients with acute leukemia had higher levels of extracellular vesicle tissue factor (EVTF) activity, phosphatidylserine-positive extracellular vesicles, plasminogen activator inhibitor-1, plasmin-antiplasmin complexes, and cell-free DNA and lower levels of citrullinated histone H3-DNA complexes compared with normal controls. APL patients had the highest levels of EVTF activity and the lowest levels of tissue plasminogen activator among acute leukemia patients. There were 41 bleeding and 23 DVT events in acute leukemia patients. High EVTF activity was associated with increased risk of bleeding (subdistribution hazard ratio, 2.30; 95% CI, 0.99-5.31), whereas high levels of plasminogen activator inhibitor-1 were associated with increased risk of DVT (subdistribution hazard ratio, 3.00; 95% CI, 0.95-9.47) in these patients.

CONCLUSION

Our study shows alterations in several biomarkers in acute leukemia and identifies biomarkers associated with risk of bleeding and DVT.

Extracellular traps in skin lesions infected with lymphocystis disease virus in black rockfish (Sebastes schlegelii)

The lymphocystis disease (LCD), caused by Lymphocystis disease virus (LCDV), is a benign and self-limiting disease described in a many freshwater and marine fish species. Hypertrophic fibroblasts and extensive aggregation of inflammatory cells are characteristics of LCD. In the present study, small animal imaging and ultrastructural investigations were carried out on the lymphocystis nodules of black rockfish (Sebastes schlegelii) naturally infected with lymphocystis iridovirus, to assess pathology, and the exudate with particular attention to the formation of extracellular traps (ETs) in vivo. Ex vivo were examined by nodules sections and primary cells stimulation. By histopathological analysis, the nodules contained infiltrated inflammatory cells and extensive basophilic fibrillar filaments at the periphery of the hypertrophied fibroblasts. ETs were assessed in nodules samples using indirect immunofluorescence to detect DNA and myeloperoxidase. Moreover, LCDV was able to infect peritoneal cells of black rockfish in vitro and induce the formation of ETs within 4 h. In summary, this study proved that ETs are involved in the response to LCDV infection and may be involved in formation of lymphoid nodules. Taken together, the findings provide a new perspective to determine the impact factors on the growth of nodules.

Targeting extranuclear histones to alleviate acute and chronic inflammation

Extracellular histones instigate an inflammatory triad - centered on cytotoxicity, immune cell stimulation, and coagulation - ultimately shaping the dynamics and outcome of various inflammatory pathologies. Given the virtual absence of beneficial functions of histones in the extracellular space, in recent years a number of interference strategies have emerged. In this review we summarize pathogenic functions of extracellular histones and highlight current developments of therapeutic interference. Finally, we elaborate on the current status of preclinical attempts to interfere with extracellular histones in the context of a focus on sepsis and cardiovascular diseases, both of which are leading causes of mortality worldwide.

IL-8 Induces Neutrophil Extracellular Trap Formation in Severe Thermal Injury

Neutrophil extracellular traps (NETs) have a dual role in the innate immune response to thermal injuries. NETs provide an early line of defence against infection. However, excessive NETosis can mediate the pathogenesis of immunothrombosis, disseminated intravascular coagulation (DIC) and multiple organ failure (MOF) in sepsis. Recent studies suggest that high interleukin-8 (IL-8) levels in intensive care unit (ICU) patients significantly contribute to excessive NET generation. This study aimed to determine whether IL-8 also mediates NET generation in patients with severe thermal injuries. IL-8 levels were measured in serum samples from thermally injured patients with ≥15% of the total body surface area (TBSA) and healthy controls (HC). Ex vivo NET generation was also investigated by treating isolated neutrophils with serum from thermal injured patients or normal serum with and without IL-8 and anti-IL-8 antibodies. IL-8 levels were significantly increased compared to HC on days 3 and 5 (p < 0.05) following thermal injury. IL-8 levels were also significantly increased at day 5 in septic versus non-septic patients (p < 0.001). IL-8 levels were also increased in patients who developed sepsis compared to HC at days 3, 5 and 7 (p < 0.001), day 10 (p < 0.05) and days 12 and 14 (p < 0.01). Serum containing either low, medium or high levels of IL-8 was shown to induce ex vivo NETosis in an IL-8-dependent manner. Furthermore, the inhibition of DNase activity in serum increased the NET-inducing activity of IL-8 in vitro by preventing NET degradation. IL-8 is a major contributor to NET formation in severe thermal injury and is increased in patients who develop sepsis. We confirmed that DNase is an important regulator of NET degradation but also a potential confounder within assays that measure serum-induced ex vivo NETosis.

Role of inflammation and evidence for the use of colchicine in patients with acute coronary syndrome

Acute Coronary Syndrome (ACS) significantly contributes to cardiovascular death worldwide. ACS may arise from the disruption of an atherosclerotic plaque, ultimately leading to acute ischemia and myocardial infarction. In the pathogenesis of atherosclerosis, inflammation assumes a pivotal role, not solely in the initiation and complications of atherosclerotic plaque formation, but also in the myocardial response to ischemic insult. Acute inflammatory processes, coupled with time to reperfusion, orchestrate ischemic and reperfusion injuries, dictating infarct magnitude and acute left ventricular (LV) remodeling. Conversely, chronic inflammation, alongside neurohumoral activation, governs persistent LV remodeling. The interplay between chronic LV remodeling and recurrent ischemic episodes delineates the progression of the disease toward heart failure and cardiovascular death. Colchicine exerts anti-inflammatory properties affecting both the myocardium and atherosclerotic plaque by modulating the activity of monocyte/macrophages, neutrophils, and platelets. This modulation can potentially result in a more favorable LV remodeling and forestalls the recurrence of ACS. This narrative review aims to delineate the role of inflammation across the different phases of ACS pathophysiology and describe the mechanistic underpinnings of colchicine, exploring its purported role in modulating each of these stages.

Autoimmune diseases and atherosclerotic cardiovascular disease

Autoimmune diseases are associated with a dramatically increased risk of atherosclerotic cardiovascular disease and its clinical manifestations. The increased risk is consistent with the notion that atherogenesis is modulated by both protective and disease-promoting immune mechanisms. Notably, traditional cardiovascular risk factors such as dyslipidaemia and hypertension alone do not explain the increased risk of cardiovascular disease associated with autoimmune diseases. Several mechanisms have been implicated in mediating the autoimmunity-associated cardiovascular risk, either directly or by modulating the effect of other risk factors in a complex interplay. Aberrant leukocyte function and pro-inflammatory cytokines are central to both disease entities, resulting in vascular dysfunction, impaired resolution of inflammation and promotion of chronic inflammation. Similarly, loss of tolerance to self-antigens and the generation of autoantibodies are key features of autoimmunity but are also implicated in the maladaptive inflammatory response during atherosclerotic cardiovascular disease. Therefore, immunomodulatory therapies are potential efficacious interventions to directly reduce the risk of cardiovascular disease, and biomarkers of autoimmune disease activity could be relevant tools to stratify patients with autoimmunity according to their cardiovascular risk. In this Review, we discuss the pathophysiological aspects of the increased cardiovascular risk associated with autoimmunity and highlight the many open questions that need to be answered to develop novel therapies that specifically address this unmet clinical need.

Plasma levels of bactericidal/permeability-increasing protein correlate with systemic inflammation in acute coronary syndrome

Background

Neutrophils play important roles in atherosclerosis and atherothrombosis. Bactericidal/permeability-increasing protein (BPI) is mainly expressed in the granules of human neutrophils in response to inflammatory stress. This observational, cross-sectional study investigated the plasma level of BPI in patients with acute coronary syndrome (ACS) and its correlation with blood neutrophil counts and circulating inflammatory biomarkers.

Methods

A total of 367 patients who had acute chest pain and who were admitted to our hospital for coronary angiography (CAG) and/or percutaneous coronary intervention (PCI) from May 1, 2020 to August 31, 2020 were recruited. Among them, 256 had a cardiac troponin value above the 99th percentile upper reference limit and were diagnosed with ACS. The remaining patients (n = 111) were classified as non-ACS. The TIMI and GRACE scores were calculated at admission. The Gensini score based on CAG was used to determine atherosclerotic burden. Plasma levels of interleukin (IL)-1β, myeloperoxidase-DNA (MPO-DNA), high sensitivity C-reactive protein (hs-CRP), S100A8/A9, and BPI were measured using enzyme-linked immunosorbent assays. Correlations of plasma BPI levels with examination scores and levels of circulating inflammatory biomarkers were explored. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic efficacy of BPI for ACS and myocardial infarction.

Results

Patients in the ACS group showed significantly higher plasma BPI levels compared to the non-ACS group (46.42 ± 16.61 vs. 16.23 ± 6.19 ng/mL, p < 0.05). Plasma levels of IL-1β, MPO-DNA, hs-CRP, and S100A8/A9 in the ACS group were also significantly higher than those in the non-ACS group (all p < 0.05). In addition, plasma BPI levels were positively correlated with the TIMI, GRACE, and Gensini scores (r = 0.176, p = 0.003; r = 0.320, p < 0.001; r = 0.263, p < 0.001, respectively) in patients with ACS. Plasma BPI levels were also positively correlated with blood neutrophil counts (r = 0.266, p < 0.001) and levels of circulating inflammatory biomarkers (IL-1β, r = 0.512; MPO-DNA, r = 0.452; hs-CRP, r = 0.554; S100A8/A9, r = 0.434; all p < 0.001) in patients with ACS. ROC curve analysis revealed that the diagnostic efficacy of BPI for ACS was not inferior to that of IL-1β, MPO-DNA, hs-CRP, S100A8/A9, or blood neutrophil counts. ROC analysis also showed that the diagnostic efficacy of BPI for myocardial infarction was not inferior to that of creatine kinase (CK)-MB or cardiac troponin I.

Conclusion

BPI is associated with systemic inflammation in ACS and may be involved in the process of atherosclerosis and atherothrombosis. The potential of BPI as a prognostic and diagnostic biomarker for ACS should be investigated in clinical settings.

Shaping the immune-suppressive microenvironment on tumor-associated myeloid cells through tumor-derived exosomes

Tumor-associated myeloid cells (TAMCs) play a crucial role in orchestrating the dynamics of the tumor immune microenvironment. This heterogeneous population encompasses myeloid-derived suppressor cells, tumor-associated macrophages and dendritic cells, all of which contribute to the establishment of an immunosuppressive milieu that fosters tumor progression. Tumor-derived exosomes (TEXs), small extracellular vesicles secreted by tumor cells, have emerged as central mediators in intercellular communication within the tumor microenvironment. In this comprehensive review, we explore the intricate mechanisms through which TEXs modulate immune-suppressive effects on TAMCs and their profound implications in cancer progression. We delve into the multifaceted ways in which TEXs influence TAMC functions, subsequently affecting tumor immune evasion. Furthermore, we elucidate various therapeutic strategies aimed at targeting TEX-mediated immune suppression, with the ultimate goal of bolstering antitumor immunity.

Between good and evil: Complexation of the human cathelicidin LL-37 with nucleic acids

The innate immune system provides a crucial first line of defense against invading pathogens attacking the body. As the only member of the human cathelicidin family, the antimicrobial peptide LL-37 has been shown to have antiviral, antifungal, and antibacterial properties. In complexation with nucleic acids, LL-37 is suggested to maintain its beneficial health effects while also acting as a condensation agent for the nucleic acid. Complexes formed by LL-37 and nucleic acids have been shown to be immunostimulatory with a positive impact on the human innate immune system. However, some studies also suggest that in some circumstances, LL-37/nucleic acid complexes may be a contributing factor to autoimmune disorders such as psoriasis and systemic lupus erythematosus. This review provides a comprehensive discussion of research highlighting the beneficial health effects of LL-37/nucleic acid complexes, as well as discussing observed detrimental effects. We will emphasize why it is important to investigate and elucidate structural characteristics, such as condensation patterns of nucleic acids within complexation, and their mechanisms of action, to shed light on the intricate physiological effects of LL-37 and the seemingly contradictory role of LL-37/nucleic acid complexes in the innate immune response.

Contribution of staphylococcal virulence factors in the pathogenesis of thrombosis

Staphylococci are responsible for many infections in humans, starting with skin and soft tissue infections and finishing with invasive diseases such as endocarditis, sepsis and pneumonia, which lead to high mortality. Patients with sepsis often demonstrate activated clotting pathways, decreased levels of anticoagulants, decreased fibrinolysis, activated endothelial surfaces and activated platelets. This results in disseminated intravascular coagulation and formation of a microthrombus, which can lead to a multiorgan failure. This review describes various staphylococcal virulence factors that contribute to vascular thrombosis, including deep vein thrombosis in infected patients. The article presents mechanisms of action of different factors released by bacteria in various host defense lines, which in turn can lead to formation of blood clots in the vessels.

Right Lower Pulmonary Vein Thrombi and Right Upper Pulmonary Vein Thrombi Connected on the Anterior Wall of the Left Atrium

The interaction between the right upper pulmonary vein (RUPV) and the right lower pulmonary vein (RLPV) is poorly understood. In this paper, using transesophageal echocardiography (TEE) and 80-slice multidetector computed tomography (80-MDCT), we report that the RUPV thrombi and the RLPV thrombi invade the left atrium (LA) and reach the anterior wall of the LA. To our knowledge, this is the first study to directly show the connection between the RUPV thrombi and the RLPV thrombi on the anterior wall of the LA using TEE and 80-MDCT.

NETosis in tumour microenvironment of liver: From primary to metastatic hepatic carcinoma

BACKGROUND

Hepatocellular carcinoma is a common and highly lethal tumour. The tumour microenvironment (TME) plays an important role in the progression and metastasis of hepatocellular carcinoma (HCC). A cell death mechanism, termed NETosis, has been found to play an important role in the TME of HCC.

SUMMARY

This review article focuses on the role of NETosis in the TME of HCC, a novel form of cell death in which neutrophils capture and kill microorganisms by releasing a type of DNA meshwork fibres called "NETs". This process is associated with neutrophil activation, local inflammation and cytokines. The study suggests that NETs play a multifaceted role in the development and metastasis of HCC. The article also discusses the role of NETs in tumour proliferation and metastasis, epithelial-mesenchymal transition (EMT), and surgical stress. In addition, the article discusses the interaction of NETosis with other immune cells in the TME and related therapeutic strategies. A deeper understanding of NETosis can help us better understand the complexity of the immune system and provide a new therapeutic basis for the treatment and prevention of HCC.

KEY INFORMATION

In conclusion, NETosis is important in the TME of liver. NETs have been shown to contribute to the progression and metastasis of liver cancer. The interaction between NETosis and immune cells in the TME, as well as related therapies, are important areas of research.

Sepsis in elderly patients: the role of neutrophils in pathophysiology and therapy

Sepsis is among the most important causes of mortality, particularly within the elderly population. Sepsis prevalence is on the rise due to different factors, including increasing average population age and the concomitant rise in the prevalence of frailty and chronic morbidities. Recent investigations have unveiled a "trimodal" trajectory for sepsis-related mortality, with the ultimate zenith occurring from 60 to 90 days until several years after the original insult. This prolonged temporal course ostensibly emanates from the sustained perturbation of immune responses, persevering beyond the phase of clinical convalescence. This phenomenon is particularly associated with the aging immune system, characterized by a broad dysregulation commonly known as "inflammaging." Inflammaging associates with a chronic low-grade activation of the innate immune system preventing an appropriate response to infective agents. Notably, during the initial phases of sepsis, neutrophils-essential in combating pathogens-may exhibit compromised activity. Paradoxically, an overly zealous neutrophilic reaction has been observed to underlie multi-organ dysfunction during the later stages of sepsis. Given this scenario, discovering treatments that can enhance neutrophil activity during the early phases of sepsis while curbing their overactivity in the later phases could prove beneficial in fighting pathogens and reducing the detrimental effects caused by an overactive immune system. This narrative review delves into the potential key role of neutrophils in the pathological process of sepsis, focusing on how the aging process impacts their functions, and highlighting possible targets for developing immune-modulatory therapies. Additionally, the review includes tables that outline the principal potential targets for immunomodulating agents.

Neutrophil extracellular traps formation may be involved in the association of propranolol with the development of portal vein thrombosis

BACKGROUND & AIMS

Nonselective β blockers (NSBBs) facilitate the development of portal vein thrombosis (PVT) in liver cirrhosis. Considering the potential effect of NSBBs on neutrophils and neutrophil extracellular traps (NETs), we speculated that NSBBs might promote the development of PVT by stimulating neutrophils to release NETs.

MATERIALS AND METHODS

Serum NETs biomarkers were measured, use of NSBBs was recorded, and PVT was evaluated in cirrhotic patients. Carbon tetrachloride and ferric chloride (FeCl3) were used to induce liver fibrosis and PVT in mice, respectively. After treatment with propranolol and DNase I, neutrophils in peripheral blood, colocalization and expression of NETs in PVT specimens, and NETs biomarkers in serum were measured. Ex vivo clots lysis analysis was performed and portal vein velocity and coagulation parameters were tested.

RESULTS

Serum MPO-DNA level was significantly higher in cirrhotic patients treated with NSBBs, and serum H3Cit and MPO-DNA levels were significantly higher in those with PVT. In fibrotic mice, following treatment with propranolol, DNase I significantly shortened the time of FeCl3-induced PVT formation, lowered the peripheral blood neutrophils labelled by CD11b/Ly6G, inhibited the positive staining of H3Cit and the expression of H3Cit and MPO proteins in PVT tissues, and reduced serum nucleosome level. Furthermore, the addition of DNase I to tissue plasminogen activator (tPA) significantly accelerated clots lysis as compared with tPA alone. Propranolol reduced portal vein velocity in fibrotic mice, but did not influence coagulation parameters.

CONCLUSION

Our study provides a clue to the potential impact of NETs formation on the association of NSBBs with the development of PVT.

The role of neutrophils and neutrophil extracellular traps (NETs) in stages, outcomes and pregnancy complications

Neutrophils are the main components of innate immunity to eliminate infectious pathogens. Neutrophils play a role in several stages of the reproductive cycle, and their presence in the female reproductive system is highly regulated, so their function may change during pregnancy. Emerging evidence suggests that neutrophils are important at all stages of pregnancy, from implantation, placentation, and connective tissue regeneration to birth, as well as birth itself. Neutrophil extracellular traps (NETs) are defined as extracellular strands of unfolded DNA together with histone complexes and neutrophil granule proteins. NET formation is a new mechanism of these cells for their defense function. These strands containing DNA and antimicrobial peptides were initially recognized as one of the defense mechanisms of neutrophils, but later it was explained that they are involved in a variety of non-infectious diseases. Since the source of inflammation and tissue damage is the irregular activity of neutrophils, it is not surprising that NETosis are associated with a number of inflammatory conditions and diseases. The overexpression of NET components or non-principled NET clearance is associated with the risk of production and activation of autoantibodies, which results in participation in autoinflammatory and autoimmune disorders (SLE, RA), fibrosis, sepsis and other disorders such as vascular diseases, for example, thrombosis and atherosclerosis. Recent published articles have shown the role of neutrophils and extracellular traps (NETs) in pregnancy, childbirth and pregnancy-related diseases. The aim of this study was to identify and investigate the role of neutrophils and neutrophil extracellular traps (NETs) in the stages of pregnancy, as well as the complications caused by these cells.

Neutrophil extracellular trap formation and its implications in nonsteroidal anti-inflammatory drug-induced small intestinal injury

BACKGROUND AND AIM

Nonsteroidal anti-inflammatory drugs (NSAIDs) damage the small intestine via neutrophil infiltration driven by the mucosal invasion of enterobacteria. The antimicrobial function of neutrophils is partially dependent on neutrophil extracellular traps (NETs). Excessive NET formation has been associated with several inflammatory diseases. Here, we aimed to investigate the role of NETs in NSAID-induced small intestinal damage using human samples and an experimental mouse model.

METHODS

Human small intestine specimens were obtained from NSAID users during double-balloon enteroscopy. Wild-type, protein arginine deiminase 4 (PAD4) knockout, and antibiotic-treated mice were administered indomethacin to induce small intestinal injury. The expression of NET-associated proteins, including PAD4, citrullinated histone H3 (CitH3), cell-free DNA, and myeloperoxidase (MPO), was evaluated.

RESULTS

The double-positive stained area with CitH3 and MPO, which is specific for neutrophil-derived extracellular traps, was significantly high in the injured small intestinal mucosa of NSAID users. In a mouse model, small intestinal damage developed at 6 h after indomethacin administration, accompanied by increased mRNA levels of interleukin-1β and keratinocyte chemoattractant and elevated NET-associated protein levels of PAD4, CitH3, and MPO in small intestine and serum levels of cell-free DNA. Both genetic deletion and pharmacological inhibition of PAD4 attenuated this damage by reducing the mRNA expression of inflammatory cytokines and NET-associated proteins. Furthermore, mice pretreated with antibiotics showed resistance to indomethacin-induced small intestinal damage, with less NET formation.

CONCLUSION

These results suggest that NETs aggravate NSAID-induced small intestinal injury. Therefore, NET inhibition could be a potential treatment for NSAID-induced small intestinal injury.

Immunological role of Gas6/TAM signaling in hemostasis and thrombosis

The immune system is an emerging regulator of hemostasis and thrombosis. The concept of immunothrombosis redefines the relationship between coagulation and immunomodulation, and the Gas6/Tyro3-Axl-MerTK (TAM) signaling pathway builds the bridge across them. During coagulation, Gas6/TAM signaling pathway not only activates platelets, but also promotes thrombosis through endothelial cells and vascular smooth muscle cells involved in inflammatory responses. Thrombosis appears to be a common result of a Gas6/TAM signaling pathway-mediated immune dysregulation. TAM TK and its ligands have been found to be involved in coagulation through the PI3K/AKT or JAK/STAT pathway in various systemic diseases, providing new perspectives in the understanding of immunothrombosis. Gas6/TAM signaling pathway serves as a breakthrough target for novel therapeutic strategies to improve disease management. Many preclinical and clinical studies of TAM receptor inhibitors are in process, confirming the pivotal role of Gas6/TAM signaling pathway in immunothrombosis. Therapeutics targeting the TAM receptor show potential both in anticoagulation management and immunotherapy. Here, we review the immunological functions of the Gas6/TAM signaling pathway in coagulation and its multiple mechanisms in diseases identified to date, and discuss the new clinical strategies that may generated by these roles.

Relationship between thrombus vWF and NETs with clinical severity and peripheral blood immunocytes' indicators in patients with acute ischemic stroke

OBJECTIVE

To investigate the association between von Willebrand factor (vWF) and neutrophil extracellular traps (NETs) in thrombus with clinical severity and peripheral blood immunocytes' indicators in patients with early-stage acute ischemic stroke (AIS).

METHODS

A retrospective study was conducted using the clinical data of 66 patients with AIS who underwent endovascular mechanical thrombectomy and had their thrombus samples collected. The concentrations of vWF and NETs in the thrombus samples were quantitatively assessed. Peripheral blood samples taken in the early stages of the disease were analyzed for total white blood cell counts (WBC), ratios of neutrophils (NEU%), lymphocytes (LYM%), eosinophils (EOS%), and monocytes (MONO%). The severity of clinical symptoms in these patients was evaluated using the modified Rankin Scale (mRS), Essen Stroke Risk Score (ESRS), Barthel Index (BI), and National Institute of Health Stroke Scale (NIHSS).

RESULTS

Higher vWF levels in thrombus were associated with lower NIHSS scores, while higher NETs levels were associated with higher initial NIHSS scores. In the early stages of AIS, WBC count and vWF levels were negatively correlated, as well as NEU%. LYM% was positively correlated with vWF level; however, it was negatively correlated with NETs. EOS% was positively correlated with vWF levels.

CONCLUSION

In the early stages of AIS, a higher peripheral WBC count and NEU%, combined with decreased EOS% and LYM%, were significantly correlated with a lower vWF level in the thrombus, potentially indicating more severe symptoms. Consequently, the timely administration of vWF-targeted medications is recommended for such patients. Reduced LYM% is indicative of elevated NETs levels and correlated with more severe clinical symptoms. Therefore, the prompt initiation of NETs-targeted medication is warranted for these patients.

The role of leukocytes in myeloproliferative neoplasm thromboinflammation

Classic myeloproliferative neoplasms lacking the Philadelphia chromosome are stem cell disorders characterized by the proliferation of myeloid cells in the bone marrow and increased counts of peripheral blood cells. The occurrence of thrombotic events is a common complication in myeloproliferative neoplasms. The heightened levels of cytokines play a substantial role in the morbidity and mortality of these patients, establishing a persistent proinflammatory condition that culminates in thrombosis. The etiology of thrombosis remains intricate and multifaceted, involving blood cells and endothelial dysfunction, the inflammatory state, and the coagulation cascade, leading to hypercoagulability. Leukocytes play a pivotal role in the thromboinflammatory process of myeloproliferative neoplasms by releasing various proinflammatory and prothrombotic factors as well as interacting with other cells, which contributes to the amplification of the clotting cascade and subsequent thrombosis. The correlation between increased leukocyte counts and thrombotic risk has been established. However, there is a need for an accurate biomarker to assess leukocyte activation. Lastly, tailored treatments to address the thrombotic risk in myeloproliferative neoplasms are needed. Therefore, this review aims to summarize the potential mechanisms of leukocyte involvement in myeloproliferative neoplasm thromboinflammation, propose potential biomarkers for leukocyte activation, and discuss promising treatment options for controlling myeloproliferative neoplasm thromboinflammation.

Targeting neutrophil extracellular trap accumulation under flow in patients with immune-mediated thrombotic thrombocytopenic purpura

ABSTRACT

Neutrophil NETosis is a unique form of cell death, characterized by the release of decondensed chromatin and antimicrobial contents to the extracellular space, which is involved in inflammation and thrombosis. However, the role of NETosis in the pathogenesis of immune-mediated thrombotic thrombocytopenic purpura (iTTP) and how a targeted therapy affects the accumulation of neutrophil extracellular traps (NETs) under flow remain unknown. Flow cytometry demonstrated that the percentage of neutrophils undergoing NETosis in whole blood from patients with iTTP on admission was significantly increased, with a concurrent decrease in the capacity of inducible NETosis by shigatoxin. After therapy, the percentage of H3Cit+MPO+ neutrophils was significantly reduced, with an improvement in inducible NETosis in these patients. Additionally, little to no NET and thrombus formation was detected underflow in the whole blood from patients with iTTP when platelet counts were very low, but the NET and thrombus formation was dramatically increased following therapy when platelet counts rose to ≥50 × 109/L or were restored to normal with donor platelets. Similarly, there was no thrombus or NET accumulation under flow in the whole blood from vwf-/- mice, but NET accumulation was significantly higher in Adamts13-/- mice than in wild-type mice. Finally, recombinant ADAMTS13 or caplacizumab (or anfibatide) prevented NET and thrombus formation under flow in whole blood from patients with iTTP or from Adamts13-/- mice. These results indicate that neutrophil NETosis and NET formation depend on platelets and von Willebrand factor (VWF) in iTTP, and a targeted therapy such as recombinant ADAMTS13 or caplacizumab may prevent NET and thrombus formation under flow in iTTP.

Interactions between integrin α9β1 and VCAM-1 promote neutrophil hyperactivation and mediate poststroke DVT

ABSTRACT

Venous thromboembolic events are significant contributors to morbidity and mortality in patients with stroke. Neutrophils are among the first cells in the blood to respond to stroke and are known to promote deep vein thrombosis (DVT). Integrin α9 is a transmembrane glycoprotein highly expressed on neutrophils and stabilizes neutrophil adhesion to activated endothelium via vascular cell adhesion molecule 1 (VCAM-1). Nevertheless, the causative role of neutrophil integrin α9 in poststroke DVT remains unknown. Here, we found higher neutrophil integrin α9 and plasma VCAM-1 levels in humans and mice with stroke. Using mice with embolic stroke, we observed enhanced DVT severity in a novel model of poststroke DVT. Neutrophil-specific integrin α9-deficient mice (α9fl/flMrp8Cre+/-) exhibited a significant reduction in poststroke DVT severity along with decreased neutrophils and citrullinated histone H3 in thrombi. Unbiased transcriptomics indicated that α9/VCAM-1 interactions induced pathways related to neutrophil inflammation, exocytosis, NF-κB signaling, and chemotaxis. Mechanistic studies revealed that integrin α9/VCAM-1 interactions mediate neutrophil adhesion at the venous shear rate, promote neutrophil hyperactivation, increase phosphorylation of extracellular signal-regulated kinase, and induce endothelial cell apoptosis. Using pharmacogenomic profiling, virtual screening, and in vitro assays, we identified macitentan as a potent inhibitor of integrin α9/VCAM-1 interactions and neutrophil adhesion to activated endothelial cells. Macitentan reduced DVT severity in control mice with and without stroke, but not in α9fl/flMrp8Cre+/- mice, suggesting that macitentan improves DVT outcomes by inhibiting neutrophil integrin α9. Collectively, we uncovered a previously unrecognized and critical pathway involving the α9/VCAM-1 axis in neutrophil hyperactivation and DVT.

The role of platelets in central hubs of inflammation: A literature review

Platelets are increasingly recognized for their multifaceted roles in inflammation beyond their traditional involvement in haemostasis. This review consolidates knowledge on platelets as critical players in inflammatory responses. This study did an extensive search of electronic databases and identified studies on platelets in inflammation, focusing on molecular mechanisms, cell interactions, and clinical implications, emphasizing recent publications. Platelets contribute to inflammation via surface receptors, release of mediators, and participation in neutrophil extracellular trap formation. They are implicated in diseases like atherosclerosis, rheumatoid arthritis, and sepsis, highlighting their interaction with immune cells as pivotal in the onset and resolution of inflammation. Platelets are central to regulating inflammation, offering new therapeutic targets for inflammatory diseases. Future research should explore specific molecular pathways of platelets in inflammation for therapeutic intervention.

Endothelial PTP1B Deletion Promotes VWF Exocytosis and Venous Thromboinflammation

BACKGROUND

Endothelial activation promotes the release of procoagulant extracellular vesicles and inflammatory mediators from specialized storage granules. Endothelial membrane exocytosis is controlled by phosphorylation. We hypothesized that the absence of PTP1B (protein tyrosine phosphatase 1B) in endothelial cells promotes venous thromboinflammation by triggering endothelial membrane fusion and exocytosis.

METHODS

Mice with inducible endothelial deletion of PTP1B (End.PTP1B-KO) underwent inferior vena cava ligation to induce stenosis and venous thrombosis. Primary endothelial cells from transgenic mice and human umbilical vein endothelial cells were used for mechanistic studies.

RESULTS

Vascular ultrasound and histology showed significantly larger venous thrombi containing higher numbers of Ly6G (lymphocyte antigen 6 family member G)-positive neutrophils in mice with endothelial PTP1B deletion, and intravital microscopy confirmed the more pronounced neutrophil recruitment following inferior vena cava ligation. RT2 PCR profiler array and immunocytochemistry analysis revealed increased endothelial activation and adhesion molecule expression in primary End.PTP1B-KO endothelial cells, including CD62P (P-selectin) and VWF (von Willebrand factor). Pretreatment with the NF-κB (nuclear factor kappa B) kinase inhibitor BAY11-7082, antibodies neutralizing CD162 (P-selectin glycoprotein ligand-1) or VWF, or arginylglycylaspartic acid integrin-blocking peptides abolished the neutrophil adhesion to End.PTP1B-KO endothelial cells in vitro. Circulating levels of annexin V+ procoagulant endothelial CD62E+ (E-selectin) and neutrophil (Ly6G+) extracellular vesicles were also elevated in End.PTP1B-KO mice after inferior vena cava ligation. Higher plasma MPO (myeloperoxidase) and Cit-H3 (citrullinated histone-3) levels and neutrophil elastase activity indicated neutrophil activation and extracellular trap formation. Infusion of End.PTP1B-KO extracellular vesicles into C57BL/6J wild-type mice most prominently enhanced the recruitment of endogenous neutrophils, and this response was blunted in VWF-deficient mice or by VWF-blocking antibodies. Reduced PTP1B binding and tyrosine dephosphorylation of SNAP23 (synaptosome-associated protein 23) resulting in increased VWF exocytosis and neutrophil adhesion were identified as mechanisms, all of which could be restored by NF-κB kinase inhibition using BAY11-7082.

CONCLUSIONS

Our findings show that endothelial PTP1B deletion promotes venous thromboinflammation by enhancing SNAP23 phosphorylation, endothelial VWF exocytosis, and neutrophil recruitment.