Tissue factor and thrombosis: The clot starts here

Cutting edge of immune response and immunosuppressants in allogeneic and xenogeneic islet transplantation

As an effective treatment for diabetes, islet transplantation has garnered significant attention and research in recent years. However, immune rejection and the toxicity of immunosuppressive drugs remain critical factors influencing the success of islet transplantation. While immunosuppressants are essential in reducing immune rejection reactions and can significantly improve the survival rate of islet transplants, improper use of these drugs can markedly increase mortality rates following transplantation. Additionally, the current availability of islet organ donations fails to meet the demand for organ transplants, making xenotransplantation a crucial method for addressing organ shortages. This review will cover the following three aspects: 1) the immune responses occurring during allogeneic islet transplantation, including three stages: inflammation and IBMIR, allogeneic immune response, and autoimmune recurrence; 2) commonly used immunosuppressants in allogeneic islet transplantation, including calcineurin inhibitors (Cyclosporine A, Tacrolimus), mycophenolate mofetil, glucocorticoids, and Bortezomib; and 3) early and late immune responses in xenogeneic islet transplantation and the immune effects of triple therapy (ECDI-fixed donor spleen cells (ECDI-SP) + anti-CD20 + Sirolimus) on xenotransplantation.

Beyond Anticoagulation: A Comprehensive Review of Non-Vitamin K Oral Anticoagulants (NOACs) in Inflammation and Protease-Activated Receptor Signaling

Non-vitamin K oral anticoagulants (NOACs) have revolutionized anticoagulant therapy, offering improved safety and efficacy over traditional agents like warfarin. This review comprehensively examines the dual roles of NOACs-apixaban, rivaroxaban, edoxaban, and dabigatran-not only as anticoagulants, but also as modulators of inflammation via protease-activated receptor (PAR) signaling. We highlight the unique pharmacotherapeutic properties of each NOAC, supported by key clinical trials demonstrating their effectiveness in preventing thromboembolic events. Beyond their established anticoagulant roles, emerging research suggests that NOACs influence inflammation through PAR signaling pathways, implicating factors such as factor Xa (FXa) and thrombin in the modulation of inflammatory responses. This review synthesizes current evidence on the anti-inflammatory potential of NOACs, exploring their impact on inflammatory markers and conditions like atherosclerosis and diabetes. By delineating the mechanisms by which NOACs mediate anti-inflammatory effects, this work aims to expand their therapeutic utility, offering new perspectives for managing inflammatory diseases. Our findings underscore the broader clinical implications of NOACs, advocating for their consideration in therapeutic strategies aimed at addressing inflammation-related pathologies. This comprehensive synthesis not only enhances understanding of NOACs' multifaceted roles, but also paves the way for future research and clinical applications in inflammation and cardiovascular health.

Development and Validation of an ICU-Venous Thromboembolism Prediction Model Using Machine Learning Approaches: A Multicenter Study

Purpose

The purpose of this study was to establish and validate machine learning-based models for predicting the risk of venous thromboembolism (VTE) in intensive care unit (ICU) patients.

Patients and Methods

The clinical data of 1494 ICU patients who underwent Doppler ultrasonography or venography between December 2020 and March 2023 were extracted from three tertiary hospitals. The Boruta algorithm was used to screen the essential variables associated with VTE. Five machine learning algorithms were employed: Random Forest (RF), eXtreme Gradient Boosting (XGBoost), Support Vector Machine (SVM), Gradient Boosting Decision Tree (GBDT), and Logistic Regression (LR). Hyperparameter optimization was conducted on the predictive model of the training dataset. The performance in the validation dataset was measured using indicators, including the area under curve (AUC) of the receiver operating characteristic (ROC) curve, specificity, and F1 score. Finally, the optimal model was interpreted using the SHapley Additive exPlanation (SHAP) package.

Results

The incidence of VTE among the ICU patients in this study was 26.04%. We screened 19 crucial features for the risk prediction model development. Among the five models, the RF model performed best, with an AUC of 0.788 (95% CI: 0.738-0.838), an accuracy of 0.759 (95% CI: 0.709-0.809), a sensitivity of 0.633, and a Brier score of 0.166.

Conclusion

A machine learning-based model for prediction of VTE in ICU patients were successfully developed, which could assist clinical medical staff in identifying high-risk populations for VTE in the early stages so that prevention measures can be implemented to reduce the burden on the ICU patients.

The Impact of Cytokines on Coagulation Profile in COVID-19 Patients: Controlled for Socio-Demographic, Clinical, and Laboratory Parameters

Background: Severe coagulation abnormalities are common in patients with COVID-19 infection. We aimed to investigate the relationship between pro-inflammatory cytokines and coagulation parameters concerning socio-demographic, clinical, and laboratory characteristics. Methods: Our study included patients hospitalized during the second wave of COVID-19 in the Republic of Serbia. We collected socio-demographic, clinical, and blood-sample data for all patients. Cytokine levels were measured using flow cytometry. Results: We analyzed data from 113 COVID-19 patients with an average age of 58.15 years, of whom 79 (69.9%) were male. Longer duration of COVID-19 symptoms before hospitalization (B = 69.672; p = 0.002) and use of meropenem (B = 1237.220; p = 0.014) were predictive of higher D-dimer values. Among cytokines, higher IL-5 values significantly predicted higher INR values (B = 0.152; p = 0.040) and longer prothrombin times (B = 0.412; p = 0.043), and higher IL-6 (B = 0.137; p = 0.003) predicted longer prothrombin times. Lower IL-17F concentrations at admission (B = 0.024; p = 0.050) were predictive of higher INR values, and lower IFN-γ values (B = -0.306; p = 0.017) were predictive of higher aPTT values. Conclusions: Our findings indicate a significant correlation between pro-inflammatory cytokines and coagulation-related parameters. Factors such as the patient's level of education, gender, oxygen-therapy use, symptom duration before hospitalization, meropenem use, and serum concentrations of IL-5, IL-6, IL-17F, and IFN-γ were associated with worse coagulation-related parameters.

Neurovascular Adverse Effects of Sars-Cov-2 Vaccination

The global deployment of SARS-CoV-2 vaccines has been pivotal in curbing the COVID-19 pandemic, reducing morbidity and mortality associated with the virus. While most of these vaccines have demonstrated high efficacy and overall safety, emerging reports have highlighted potential neurovascular adverse effects, albeit uncommon, associated with these vaccinations. This review aims to assess and summarize the current knowledge on the neurovascular complications arising post-SARS-CoV-2 vaccination. We conducted an extensive literature review, focusing on clinical studies and case reports to identify reported neurovascular events, such as ischemic stroke, cerebral sinus venous thrombosis, intracerebral hemorrhage, pituitary apoplexy and primary CNS angiitis Despite the relative rarity of these events, their impact on affected individuals underscores the importance of ongoing surveillance, early detection, and management strategies. We aim to provide healthcare professionals with the latest evidence on neurovascular adverse effects, facilitating informed decision-making in the context of SARS-CoV-2 vaccination programs. Furthermore, we highlight areas requiring further research to understand the pathophysiology of these adverse events better and to develop targeted prevention and treatment strategies.

Deciphering the triad of endothelial glycocalyx, von Willebrand Factor, and P-selectin in inflammation-induced coagulation

This review examines the endothelial glycocalyx's role in inflammation and explores its involvement in coagulation. The glycocalyx, composed of proteins and glycosaminoglycans, interacts with von Willebrand Factor and could play a crucial role in anchoring it to the endothelium. In inflammatory conditions, glycocalyx degradation may leave P-selectin as the only attachment point for von Willebrand Factor, potentially leading to uncontrolled release of ultralong von Willebrand Factor in the bulk flow in a shear stress-dependent manner. Identifying specific glycocalyx glycosaminoglycan interactions with von Willebrand Factor and P-selectin can offer insights into unexplored coagulation mechanisms.

Trauma diagnostic-related target proteins and their detection techniques

Trauma is a significant health issue that not only leads to immediate death in many cases but also causes severe complications, such as sepsis, thrombosis, haemorrhage, acute respiratory distress syndrome and traumatic brain injury, among trauma patients. Target protein identification technology is a vital technique in the field of biomedical research, enabling the study of biomolecular interactions, drug discovery and disease treatment. It plays a crucial role in identifying key protein targets associated with specific diseases or biological processes, facilitating further research, drug design and the development of treatment strategies. The application of target protein technology in biomarker detection enables the timely identification of newly emerging infections and complications in trauma patients, facilitating expeditious medical interventions and leading to reduced post-trauma mortality rates and improved patient prognoses. This review provides an overview of the current applications of target protein identification technology in trauma-related complications and provides a brief overview of the current target protein identification technology, with the aim of reducing post-trauma mortality, improving diagnostic efficiency and prognostic outcomes for patients.

NADPH-oxidases as potential pharmacological targets for thrombosis and depression comorbidity

There is a complex interrelationship between the nervous system and the cardiovascular system. Comorbidities of cardiovascular diseases (CVD) with mental disorders, and vice versa, are prevalent. Adults with mental disorders such as anxiety and depression have a higher risk of developing CVD, and people with CVD have an increased risk of being diagnosed with mental disorders. Oxidative stress is one of the many pathways associated with the pathophysiology of brain and cardiovascular disease. Nicotinamide adenine dinucleotide phosphate oxidase (NOX) is one of the major generators of reactive oxygen species (ROS) in mammalian cells, as it is the enzyme that specifically produces superoxide. This review summarizes recent findings on the consequences of NOX activation in thrombosis and depression. It also discusses the therapeutic effects and pharmacological strategies of NOX inhibitors in CVD and brain disorders. A better comprehension of these processes could facilitate the development of new therapeutic approaches for the prevention and treatment of the comorbidity of thrombosis and depression.

Improvements in markers of inflammation and coagulation potential following a 5-day high-fat diet rich in cottonseed oil vs. Olive oil in healthy males

Low-grade inflammation is believed to be a risk factor for chronic diseases and is nutritionally responsive. Cottonseed oil (CSO), which is rich in n-6 polyunsaturated fats, has been shown to lower cholesterol and other chronic disease risk factors. The purpose of this secondary analysis was to determine the comparative responses of markers of inflammation and coagulation potential of healthy adult males consuming diets rich in CSO vs. olive oil (OO).

METHODS

Fifteen normal-weight males, ages 21.7 ± 2.58y, completed a randomized crossover trial. Each intervention consisted of a 3-day lead-in diet and a 5-day outpatient, controlled feeding intervention (CSO or OO). There was a 2 to 4-week washout period between interventions. The 5-day intervention diets were 35 % carbohydrate, 15 % protein, and 50 % fat, enriched with either CSO or OO (44 % of total energy from oil). At pre- and post- diet intervention visits, a fasting blood draw was collected for analysis of markers of inflammation (Tumor Necrosis Factor Alpha (TNF-α), Interleukin-6 (IL-6), C-Reactive Protein (CRP)) and coagulation potential (Tissue Factor (TF), Plasminogen Activator Inhibitor-1 (PAI-1)).

RESULTS

The CSO-enriched diets reduced TNF-α (CSO: -0.12 ± 0.02 pg/ml, OO: -0.01 ± 0.05 pg/ml; p < 0.01) and TF (CSO: -0.59 ± 0.68 pg/ml, OO: 1.13 ± 0.83 pg/ml; p = 0.02) compared to OO diets. There were no differences in IL-6, CRP, or PAI-1 between diets.

CONCLUSION

A 5-day, CSO-enriched diet may be sufficient to reduce inflammation and coagulation potential compared to OO-enriched diets in a healthy male population which could have implications in chronic disease prevention.

COVID-19 pathogenesis

The pathogenesis of COVID-19 involves a complex interplay between host factors and the SARS-CoV-2 virus, leading to a multitude of clinical manifestations beyond the respiratory system. This chapter provides an overview of the risk factors, genetic predisposition, and multisystem manifestations of COVID-19, shedding light on the underlying mechanisms that contribute to extrapulmonary manifestations. The chapter discusses the direct invasion of SARS-CoV-2 into various organs as well as the indirect mechanisms such as dysregulation of the renin-angiotensin-aldosterone system (RAAS), immune response dysfunctions within the innate and adaptive immune systems, endothelial damage, and immunothrombosis. Furthermore, the multisystem manifestations of COVID-19 across different organ systems, including the cardiovascular, renal, gastrointestinal, hepatobiliary, nervous, endocrine and metabolic, ophthalmic, ear-nose-throat, reproductive, hematopoietic, and immune systems are discussed in detail. Each system exhibits unique manifestations that contribute to the complexity of the disease.

Post-transcriptional control of haemostatic genes: mechanisms and emerging therapeutic concepts in thrombo-inflammatory disorders

The haemostatic system is pivotal to maintaining vascular integrity. Multiple components involved in blood coagulation have central functions in inflammation and immunity. A derailed haemostasis is common in prevalent pathologies such as sepsis, cardiovascular disorders, and lately, COVID-19. Physiological mechanisms limit the deleterious consequences of a hyperactivated haemostatic system through adaptive changes in gene expression. While this is mainly regulated at the level of transcription, co- and posttranscriptional mechanisms are increasingly perceived as central hubs governing multiple facets of the haemostatic system. This layer of regulation modulates the biogenesis of haemostatic components, for example in situations of increased turnover and demand. However, they can also be 'hijacked' in disease processes, thereby perpetuating and even causally entertaining associated pathologies. This review summarizes examples and emerging concepts that illustrate the importance of posttranscriptional mechanisms in haemostatic control and crosstalk with the immune system. It also discusses how such regulatory principles can be used to usher in new therapeutic concepts to combat global medical threats such as sepsis or cardiovascular disorders.

Serious neurological adverse events following immunization against SARS-CoV-2: a narrative review of the literature

Amid the coronavirus disease 2019 (COVID-19) pandemic, massive immunization campaigns became the most promising public health measure. During clinical trials, certain neurological adverse effects following immunization (AEFIs) were observed; however, acceptable safety profiles lead to emergency authorization for the distribution and use of the vaccines. To contribute to pharmacovigilance and lessen the potential negative impact that vaccine hesitancy would have on immunization programs, we conducted a review of the scientific literature concerning the epidemiological data, clinical presentation, and potential mechanisms of these neurological AEFIs. There is some epidemiological evidence linking COVID-19 vaccines to cerebral venous sinus thrombosis, arterial ischemic stroke, convulsive disorder, Guillain-Barré syndrome, facial nerve palsy, and other neurological conditions. Cerebral venous sinus thrombosis has been associated with a thrombotic thrombocytopenia induced by the vaccine, similar to that induced by heparin, which suggests similar pathogenic mechanisms (likely involving antibodies against platelet factor 4, a chemokine released from activated platelets). Arterial ischemic stroke is another thrombotic condition observed among some COVID-19 vaccine recipients. Vaccine-induced convulsive disorder might be the result of structural abnormalities potentially caused by the vaccine or autoimmune mechanisms. Guillain-Barré syndrome and facial nerve palsy may also be linked to the immunization event, possibly due to immune mechanisms such as uncontrolled cytokine release, autoantibody production, or bystander effect. However, these events are mostly uncommon and the evidence for the association with the vaccine is not conclusive. Furthermore, the potential pathophysiological mechanisms remain largely unknown. Nevertheless, neurological AEFIs can be serious, life-threatening or even fatal. In sum, COVID-19 vaccines are generally safe and the risk of neurological AEFIs does not outweigh the benefits of immunization. However, early diagnosis and treatment of neurological AEFIs are of utmost importance, and both health professionals and the public should be aware of these conditions.

Hemorrhagic Fever with Renal Syndrome in Asia: History, Pathogenesis, Diagnosis, Treatment, and Prevention

Hemorrhagic Fever with Renal Syndrome (HFRS) is the most frequently diagnosed zoonosis in Asia. This zoonotic infection is the result of exposure to the virus-contaminated aerosols. Orthohantavirus infection may cause Hemorrhagic Fever with Renal Syndrome (HRFS), a disease that is characterized by acute kidney injury and increased vascular permeability. Several species of orthohantaviruses were identified as causing infection, where Hantaan, Puumala, and Seoul viruses are most common. Orthohantaviruses are endemic to several Asian countries, such as China, South Korea, and Japan. Along with those countries, HFRS tops the list of zoonotic infections in the Far Eastern Federal District of Russia. Recently, orthohantavirus circulation was demonstrated in small mammals in Thailand and India, where orthohantavirus was not believed to be endemic. In this review, we summarized the current data on orthohantaviruses in Asia. We gave the synopsis of the history and diversity of orthohantaviruses in Asia. We also described the clinical presentation and current understanding of the pathogenesis of orthohantavirus infection. Additionally, conventional and novel approaches for preventing and treating orthohantavirus infection are discussed.

Tissue factor-dependent coagulation activation in intracranial neoplasms: a comparative study

The aim of the study was to investigate the concentration and activity of tissue factor (TF) and Tissue factor pathway inhibitor (TFPI) as well as the concentration of thrombin-antithrombin (TAT) complexes in patients with primary and metastatic intracranial neoplasms. The study included 69 patients with an average age of 62 years. Twenty-one patients were diagnosed with gliomas, 18 meningioma stage II (M) patients, and 30 metastatic brain tumour cases (Meta). The control group consisted of 30 individuals with a mean age of 57 years. In the plasma of all the participants and in tumour tissue-derived homogenate, the concentrations and activities of TF, TFPI, the concentration of TAT complexes and the concentration of total protein were measured. The results were converted per 1 mg of protein. The concentration of TF was over 80 times higher in the tumour tissue-derived homogenate in respect to patients' plasma levels. Plasma TF activity in intracranial cancer patients was almost six times higher compared with noncancer counterparts, while in the tumour tissue-derived homogenate it was more than 14 times higher than in the intracranial cancer patients' plasma, whereas the concentration of TFPI in the tumour tissue-derived homogenate was significantly lower than in the patients' plasma. However, a significantly higher TFPI activity in the tumour tissue derived than in the patients' plasma was reported. The high concentration and activity of TF, along with the coexisting low concentration and activity of TFPI in the plasma of intracranial tumour patients, is associated with a higher prothrombotic risk in these patients.

John J, Khademhosseini A. Recent advances in biopolymer-based hemostatic materials

Hemorrhage is the leading cause of trauma-related deaths, in hospital and prehospital settings. Hemostasis is a complex mechanism that involves a cascade of clotting factors and proteins that result in the formation of a strong clot. In certain surgical and emergency situations, hemostatic agents are needed to achieve faster blood coagulation to prevent the patient from experiencing a severe hemorrhagic shock. Therefore, it is critical to consider appropriate materials and designs for hemostatic agents. Many materials have been fabricated as hemostatic agents, including synthetic and naturally derived polymers. Compared to synthetic polymers, natural polymers or biopolymers, which include polysaccharides and polypeptides, have greater biocompatibility, biodegradability and processibility. Thus, in this review, we focus on biopolymer-based hemostatic agents of different forms, such as powder, particles, sponges and hydrogels. Finally, we discuss biopolymer-based hemostatic materials currently in clinical trials and offer insight into next-generation hemostats for clinical translation.

COVID-19-Related ARDS: Key Mechanistic Features and Treatments

Acute respiratory distress syndrome (ARDS) is a heterogeneous syndrome historically characterized by the presence of severe hypoxemia, high-permeability pulmonary edema manifesting as diffuse alveolar infiltrate on chest radiograph, and reduced compliance of the integrated respiratory system as a result of widespread compressive atelectasis and fluid-filled alveoli. Coronavirus disease 19 (COVID-19)-associated ARDS (C-ARDS) is a novel etiology caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that may present with distinct clinical features as a result of the viral pathobiology unique to SARS-CoV-2. In particular, severe injury to the pulmonary vascular endothelium, accompanied by the presence of diffuse microthrombi in the pulmonary microcirculation, can lead to a clinical presentation in which the severity of impaired gas exchange becomes uncoupled from lung capacity and respiratory mechanics. The purpose of this review is to highlight the key mechanistic features of C-ARDS and to discuss the implications these features have on its treatment. In some patients with C-ARDS, rigid adherence to guidelines derived from clinical trials in the pre-COVID era may not be appropriate.

Effects of Interleukin-17A on the Early Stages of Arterial Thrombosis in Mice

PURPOSE

Interleukin (IL)-17A has been suggested to play a role in the growth and organization of thrombi. We examined whether IL-17A plays a role in the early stages of thrombosis and whether there are sex differences in the effects of IL-17A.

MATERIALS AND METHODS

We performed a blinded, randomized, placebo-controlled study to compare time to thrombotic occlusion and sex differences therein between mice treated with IL-17A and those treated with saline using a ferric chloride-induced model. We also assessed thrombus histology, blood coagulation, and plasma levels of coagulation factors.

RESULTS

Time to occlusion values did not differ between the IL-17A group and the control group (94.6±86.9 sec vs. 121.0±84.4 sec, p=0.238). However, it was significantly shorter in the IL-17A group of female mice (74.6±57.2 sec vs. 130.0±76.2 sec, p=0.032). In rotational thromboelastometry, the IL-17A group exhibited increased maximum clot firmness (71.3±4.5 mm vs. 66.7±4.7 mm, p=0.038) and greater amplitude at 30 min (69.7±5.2 mm vs. 64.5±5.3 mm, p=0.040) than the control group. In Western blotting, the IL-17A group showed higher levels of coagulation factor XIII (2.2±1.5 vs. 1.0±0.9, p=0.008), monocyte chemoattractant protein-1 (1.6±0.6 vs. 1.0±0.4, p=0.023), and tissue factor (1.5±0.6 vs. 1.0±0.5, p=0.003).

CONCLUSION

IL-17A plays a role in the initial st ages of arterial thrombosis in mice. Coagulation factors and monocyte chemoattractant protein-1 may be associated with IL-17A-mediated thrombosis.

SARS-CoV-2 pathogenesis

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a devastating pandemic. Although most people infected with SARS-CoV-2 develop a mild to moderate disease with virus replication restricted mainly to the upper airways, some progress to having a life-threatening pneumonia. In this Review, we explore recent clinical and experimental advances regarding SARS-CoV-2 pathophysiology and discuss potential mechanisms behind SARS-CoV-2-associated acute respiratory distress syndrome (ARDS), specifically focusing on new insights obtained using novel technologies such as single-cell omics, organoid infection models and CRISPR screens. We describe how SARS-CoV-2 may infect the lower respiratory tract and cause alveolar damage as a result of dysfunctional immune responses. We discuss how this may lead to the induction of a 'leaky state' of both the epithelium and the endothelium, promoting inflammation and coagulation, while an influx of immune cells leads to overexuberant inflammatory responses and immunopathology. Finally, we highlight how these findings may aid the development of new therapeutic interventions against COVID-19.

Immunothrombosis and the molecular control of tissue factor by pyroptosis: prospects for new anticoagulants

The interplay between innate immunity and coagulation after infection or injury, termed immunothrombosis, is the primary cause of disseminated intravascular coagulation (DIC), a condition that occurs in sepsis. Thrombosis associated with DIC is the leading cause of death worldwide. Interest in immunothrombosis has grown because of COVID-19, the respiratory disease caused by SARS-CoV-2, which has been termed a syndrome of dysregulated immunothrombosis. As the relatively new field of immunothrombosis expands at a rapid pace, the focus of academic and pharmacological research has shifted from generating treatments targeted at the traditional 'waterfall' model of coagulation to therapies better directed towards immune components that drive coagulopathies. Immunothrombosis can be initiated in macrophages by cleavage of the non-canonical inflammasome which contains caspase-11. This leads to release of tissue factor (TF), a membrane glycoprotein receptor that forms a high-affinity complex with coagulation factor VII/VIIa to proteolytically activate factors IX to IXa and X to Xa, generating thrombin and leading to fibrin formation and platelet activation. The mechanism involves the post-translational activation of TF, termed decryption, and release of decrypted TF via caspase-11-mediated pyroptosis. During aberrant immunothrombosis, decryption of TF leads to thromboinflammation, sepsis, and DIC. Therefore, developing therapies to target pyroptosis have emerged as an attractive concept to counteract dysregulated immunothrombosis. In this review, we detail the three mechanisms of TF control: concurrent induction of TF, caspase-11, and NLRP3 (signal 1); TF decryption, which increases its procoagulant activity (signal 2); and accelerated release of TF into the intravascular space via pyroptosis (signal 3). In this way, decryption of TF is analogous to the two signals of NLRP3 inflammasome activation, whereby induction of pro-IL-1β and NLRP3 (signal 1) is followed by activation of NLRP3 (signal 2). We describe in detail TF decryption, which involves pathogen-induced alterations in the composition of the plasma membrane and modification of key cysteines on TF, particularly at the location of the critical, allosterically regulated disulfide bond of TF in its 219-residue extracellular domain. In addition, we speculate towards the importance of identifying new therapeutics to block immunothrombotic triggering of TF, which can involve inhibition of pyroptosis to limit TF release, or the direct targeting of TF decryption using cysteine-modifying therapeutics.

Biomaterials Based on Carbon Nanotube Nanocomposites of Poly(styrene-b-isobutylene-b-styrene): The Effect of Nanotube Content on the Mechanical Properties, Biocompatibility and Hemocompatibility

Nanocomposites based on poly(styrene-block-isobutylene-block-styrene) (SIBS) and single-walled carbon nanotubes (CNTs) were prepared and characterized in terms of tensile strength as well as bio- and hemocompatibility. It was shown that modification of CNTs using dodecylamine (DDA), featured by a long non-polar alkane chain, provided much better dispersion of nanotubes in SIBS as compared to unmodified CNTs. As a result of such modification, the tensile strength of the nanocomposite based on SIBS with low molecular weight (Mn = 40,000 g mol-1) containing 4% of functionalized CNTs was increased up to 5.51 ± 0.50 MPa in comparison with composites with unmodified CNTs (3.81 ± 0.11 MPa). However, the addition of CNTs had no significant effect on SIBS with high molecular weight (Mn~70,000 g mol-1) with ultimate tensile stress of pure polymer of 11.62 MPa and 14.45 MPa in case of its modification with 1 wt% of CNT-DDA. Enhanced biocompatibility of nanocomposites as compared to neat SIBS has been demonstrated in experiment with EA.hy 926 cells. However, the platelet aggregation observed at high CNT concentrations can cause thrombosis. Therefore, SIBS with higher molecular weight (Mn~70,000 g mol-1) reinforced by 1-2 wt% of CNTs is the most promising material for the development of cardiovascular implants such as heart valve prostheses.

Construction of Risk Assessment Model for Venous Thromboembolism After Colorectal Cancer Surgery: A Chinese Single-Center Study

Objective

A retrospective study was carried out to construct a postoperative venous thromboembolism (VTE) risk assessment model (RAM) applicable for Chinese colorectal cancer patients.

Methods

541 Patients who underwent colorectal cancer surgery from June 2019 to May 2020 at Sir-Run-Run-Shaw Hospital affiliated to Zhejiang University School of Medicine were enrolled in this study. Multi-factor analysis was used to determine the independent risk factors of VTE. A novel RAM of VTE which we called Sir-Run-Run-Shaw VTE RAM were constructed basing on the independent risk factors. Another study cohort consisted of 287 colorectal cancer patients underwent surgery from January 2021 to June 2021was used for model evaluation.

Results

The incidence of VTE after colorectal cancer surgery was 12.0%(65/541). Among the 65 VTE Patients, DVT accounted for 92.3% (60/65) and DVT + PE accounted for 7.7% (5/65). Multi-factor analysis showed that age ≥ 69 years ( P < 0.01), preoperative plasma D-dimer ≥ 0.49 mg/L ( P = .004), stage IV of cancer ( P = .018) and transfusion ( P = .004) are independent risk factors of VTE after surgery. Sir-Run-Run-Shaw VTE RAM includes the above 4 factors, and the total score is 4 points. The score of the low, medium and high risk groups are 0, 1 and ≥2 points. The area under the ROC curve (AUC) of Sir-Run-Run-Shaw VTE RAM is 0.769, while Caprini RAM is 0.656. There is statistical difference between the two risk score tables ( Z = 2.337, P = .0195).

Conclusion

A VTE RAM is constructed basing on a single center retrospective study. This score table may be applicable for Chinese patients with colorectal cancer surgery.

Prevalence and clinical outcomes of hospitalized patients with upper extremity deep vein thrombosis

OBJECTIVE

Upper extremity (UE) deep vein thrombosis (DVT) is a common and increasing complication in hospitalized patients. The objective of the present study was to determine the prevalence, treatment strategies, complications, and outcomes of UE-DVT.

METHODS

We performed a retrospective single-institution study of patients with a diagnosis of UE-DVT from January 2016 through February 2018 (26 months). Patients aged ≥18 years who had been admitted to the hospital and who had had positive UE duplex ultrasound findings for acute UE-DVT were included in the present study. The outcomes were in-hospital mortality, major bleeding, pulmonary embolism (PE), and recurrent UE-DVT.

RESULTS

Among 63,045 patients admitted to the hospital, 1000 (1.6%) had been diagnosed with UE-DVT. Of 3695 UE venous duplex ultrasound examinations performed during the study period, almost one third (27.0%) were positive for acute UE-DVT. The mean age was 55.0 ± 17.2 years, and most patients were men (58.3%), white (49.2%), and overweight (mean body mass index, 29.4 ± 10.3 kg/m²). The most affected vein was the right internal jugular vein (54.8%). Most of the patients (96.9%) has been receiving venous thromboembolism prophylaxis or anticoagulation therapy at the diagnosis. Most patients (77.8%) had had an intravenous device (IVD) in place at the diagnosis. Most of the patients (84.4%) were treated with anticoagulation therapy in the hospital but only one half (54.5%) were discharged with anticoagulation therapy. In-hospital mortality was 12.1% unrelated to UE-DVT, major bleeding occurred in 47.6% of the patients during hospitalization (fatal bleeding, 1%), PE was diagnosed in 4.8% of the patients, and 0.7% were fatal. Recurrent UE-DVT occurred in 6.1% of the patients. On multivariable analysis, the risk of death was increased by older age, cancer, intensive care unit admission, concomitant lower extremity DVT, and bleeding before the UE-DVT diagnosis. The presence of an IVD increased the risk of PE and the risk of recurrent UE-DVT. The risk of major bleeding was increased by the presence of an IVD, female sex, and concomitant lower extremity DVT.

CONCLUSIONS

UE-DVT is a common complication in hospitalized patients (1.6%). Consequent acute PE and recurrent DVT remain important complications, as does bleeding. It is unclear whether standard thromboprophylaxis effectively protects against UE-DVT. More studies dedicated to UE-DVT are required to provide appropriate guidance on prophylaxis and treatment.

Depression, anxiety, and vital exhaustion are associated with pro-coagulant markers in depressed patients with coronary artery disease - A cross sectional and prospective secondary analysis of the SPIRR-CAD trial

INTRODUCTION

A hyper-coagulant state is a biological mechanism that triggers cardiac events in patients with coronary artery disease (CAD). Depressive symptoms and anxiety predict an unfavourable course of CAD. The SPIRR-CAD-RCT examined the effects of a psychological intervention and provided the opportunity to explore cross-sectional associations between indices of psychological strain and coagulation parameters, as well as prospective changes in depression scores and coagulation parameters.

METHODS

In this secondary analysis, we investigated 253 CAD patients (194 male; age m 58.9, SD 8.3 yrs.) with mild to moderate depression (≥8 on the HADS-D) at baseline and at follow-up 18 months later: TF, fibrinogen, D-dimer, VWF, FVII and PAI-1 and the course of depression (HAM-D), vital exhaustion (VE) and anxiety scores (HADS-A) were examined by ANOVA in the total and younger age groups (≤ 60).

RESULTS

HAM-D at baseline was correlated with TF (corr. R² = 0.27; F = 9.31, p = 0.001). HADS anxiety was associated with fibrinogen (corr. R².20; F = 7.27, p = 0.001). There was no detectable therapeutic effect on coagulation. Fibrinogen and VWF decreased within 18 months (time effect; p = 0.02; p = 0.04), as did HADS-D in both treatment groups (p < 0.001). Fibrinogen decreased more in patients ≤60 years with high VE compared to low VE (interaction time x group, p = 0.01).

CONCLUSIONS

This is the first study to show an association between TF and depression. Coagulation parameters as potential mediators of CAD progression correlated cross-sectionally with depression and anxiety and prospectively with VE. Further studies should replicate these correlations in depressed and non-depressed CAD patients.

ISRCTN

76240576; clinicaltrials.gov.

PCSK9 Induces Tissue Factor Expression by Activation of TLR4/NFkB Signaling

Proprotein convertase subtilisin kexin 9 (PCSK9) increases LDL cholesterol (C) concentration by accelerating the hepatic degradation of the LDL receptor (R) thus promoting atherogenesis. The molecule, however, also exerts proinflammatory effects independent of circulating LDL-C by enhancing local cytokine production and activation of NFkB, a process that might involve Toll-like receptor 4 (TLR4), a crucial component of the innate immunity system. Tissue factor (TF), a glycoprotein which plays an essential role in coagulation and inflammation, is rapidly induced by circulating monocytes stimulated by proinflammatory agents through NFkB-dependent mechanisms. The aims of our study were (1) to assess whether PCSK9 may induce monocytic TF expression and (2) to evaluate whether the TLR4/NFkB signaling pathway may contribute to that effect. Experiments were carried out in peripheral blood mononuclear cells (PBMCs), THP-1 cells, and HEK293 cells transfected with plasmids encoding the human TLR4 complex. PCSK9 increased procoagulant activity (PCA), mRNA and TF protein expression in both PBMCs and THP-1 cultures. Pre-treatment with inhibitors of TLR4/NFkB signaling such as LPS-RS, CLI-095, and BAY 11-7082, downregulated PCSK9-induced TF expression. A similar effect was obtained by incubating cell cultures with anti-PCSK9 human monoclonal antibody. In TLR4-HEK293 cells, PCSK9 activated the TLR4/NFkB signaling pathway to an extent comparable to LPS, the specific agonist of TLR4s and quantitative confocal microscopy documented the colocalization of PCSK9 and TLR4s. In conclusion, PCSK9 induces TF expression through activation of TLR4/NFkB signaling.

Seaweed polysaccharides: Emerging extraction technologies, chemical modifications and bioactive properties

Nowadays, consumers are increasingly aware of the relationship between diet and health, showing a greater preference of products from natural origin. In the last decade, seaweeds have outlined as one of the natural sources with more potential to obtain bioactive carbohydrates. Numerous seaweed polysaccharides have aroused the interest of the scientific community, due to their biological activities and their high potential on biomedical, functional food and technological applications. To obtain polysaccharides from seaweeds, it is necessary to find methodologies that improve both yield and quality and that they are profitable. Nowadays, environmentally friendly extraction technologies are a viable alternative to conventional methods for obtaining these products, providing several advantages like reduced number of solvents, energy and time. On the other hand, chemical modification of their structure is a useful approach to improve their solubility and biological properties, and thus enhance the extent of their potential applications since some uses of polysaccharides are still limited. The present review aimed to compile current information about the most relevant seaweed polysaccharides, available extraction and modification methods, as well as a summary of their biological activities, to evaluate knowledge gaps and future trends for the industrial applications of these compounds.Key teaching pointsStructure and biological functions of main seaweed polysaccharides.Emerging extraction methods for sulfate polysaccharides.Chemical modification of seaweeds polysaccharides.Potential industrial applications of seaweed polysaccharides.Biological activities, knowledge gaps and future trends of seaweed polysaccharides.

Severely ill pediatric patients with Shiga toxin-associated hemolytic uremic syndrome (STEC-HUS) who suffered from multiple organ involvement in the early stage

BACKGROUND

Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (STEC-HUS) is the main cause of pediatric acute kidney injury (AKI) in Argentina. Endothelial injury is the trigger event in the microangiopathic process. The host inflammatory response to toxin and E. coli lipopolysaccharide (LPS) is involved in disease pathophysiology.

METHODS

This retrospective study describes pediatric STEC-HUS patients with multiorgan involvement at the initial phase of disease. A retrospective study of critically ill HUS patients with evidence of E. coli infection was conducted through a period of 15 years.

RESULTS

Forty-four patients 35.4 ± 4.1 months were admitted to the intensive care unit for 21 ± 2 days. Mechanical ventilation was required in 41 patients, early inotropic support in 37, and 28 developed septic shock. Forty-one patients required kidney replacement therapy for 12 ± 1 days. Forty-one patients showed neurological dysfunction. Dilated cardiomyopathy was demonstrated in 3 patients, left ventricular systolic dysfunction in 4, and hypertension in 17. Four patients had pulmonary hemorrhage, and acute respiratory distress syndrome in 2. Colectomy for transmural colonic necrosis was performed in 3 patients. Thirty-seven patients were treated with therapeutic plasma exchange, and 28 patients received methylprednisolone (10 mg/kg for 3 days). Of the surviving 32 patients, neurological sequelae were seen in 11 and chronic kidney failure in 5.

CONCLUSIONS

Severe clinical outcome at onset suggests an amplified inflammatory response after exposure to Shiga toxin and/or E. coli LPS. STEC-HUS associated with severe neurological involvement, hemodynamic instability, and AKI requires intensive care and focused therapy.

Low-density lipoproteins cause atherosclerotic cardiovascular disease: pathophysiological, genetic, and therapeutic insights: a consensus statement from the European Atherosclerosis Society Consensus Panel

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Thrombolome and Its Emerging Role in Chronic Kidney Diseases

Patients with chronic kidney disease (CKD) are at an increased risk of thromboembolic complications, including myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism. These complications lead to increased mortality. Evidence points to the key role of CKD-associated dysbiosis and its effect via the generation of gut microbial metabolites in inducing the prothrombotic phenotype. This phenomenon is known as thrombolome, a panel of intestinal bacteria-derived uremic toxins that enhance thrombosis via increased tissue factor expression, platelet hyperactivity, microparticles release, and endothelial dysfunction. This review discusses the role of uremic toxins derived from gut-microbiota metabolism of dietary tryptophan (indoxyl sulfate (IS), indole-3-acetic acid (IAA), kynurenine (KYN)), phenylalanine/tyrosine (p-cresol sulfate (PCS), p-cresol glucuronide (PCG), phenylacetylglutamine (PAGln)) and choline/phosphatidylcholine (trimethylamine N-oxide (TMAO)) in spontaneously induced thrombosis. The increase in the generation of gut microbial uremic toxins, the activation of aryl hydrocarbon (AhRs) and platelet adrenergic (ARs) receptors, and the nuclear factor kappa B (NF-κB) signaling pathway can serve as potential targets during the prevention of thromboembolic events. They can also help create a new therapeutic approach in the CKD population.

Coagulation Disorders in COVID-19: Role of Toll-like Receptors

Coronavirus disease 2019 (COVID-19) has spread rapidly throughout the world. The range of the disease is broad but among hospitalized patients with COVID-19 are coagulation disorders, pneumonia, respiratory failure, and acute respiratory distress syndrome (ARDS). The excess production of early response proinflammatory cytokines results in what has been described as a cytokine storm, leading to an increased risk of thrombosis, inflammations, vascular hyperpermeability, multi-organ failure, and eventually death over time. As the pandemic is spreading and the whole picture is not yet clear, we highlight the importance of coagulation disorders in COVID-19 infected subjects and summarize it. COVID-19 infection could induce coagulation disorders leading to clot formation as well as pulmonary embolism with detrimental effects in patient recovery and survival. Coagulation and inflammation are closely related. In this review, we try to establish an association between virus infections associated with innate immune activation, inflammation and coagulation activation.

Post-traumatic pulmonary embolism: incidence, physiopathology, risk factors of early occurrence, and impact outcome. A narrative review

BACKGROUND

Venous thromboembolism (VTE) is a well-established complication of trauma. So far, the factors that are related to early post-traumatic pulmonary embolism (PE) occurrence have been given little attention.

AIMS

We have conducted this literature review in order to analyze the incidence and the physiopathology of post-traumatic PE among intensive care unit (ICU) trauma patients, analyze the incidence of early post-traumatic PE, and elucidate risk factors associated with post-traumatic PE. Moreover, we aim to study the impact/outcome of post-traumatic PE in the ICU.

METHODS

We used the PubMed and EMBASE databases and entered the following key words in MeSH research: Deep vein thrombosis (DVT), Post-traumatic Pulmonary embolism, Early pulmonary-embolism, risk factors, and Prognosis.

RESULTS

The incidence of PE among trauma patients varies considerably, ranging from 0.35% to 24%. The incidence of early post-traumatic PE varies widely from 10 to 42%. After a traumatic injury, many factors have been found to be responsible for the formation of DVT and PE. In addition to the risk factors of hypercoagulability described by Virchow in his original triad, inflammation acting via endothelial damage may be considered as a fourth factor. The literature review showed that lower limb fractures and age are the most frequent factors associated with PE (particularly in early PE). The heterogeneity among studies limits reliable conclusions regarding the true risk factors for the timing of the occurrence of post-traumatic PE. Fatality from pulmonary embolism (PE) is close to 50% in some series. Moreover, high mortality rates, a high rate of nosocomial infections, and a prolonged stay in an ICU and/or in a hospital were found to be associated with the development of PE.

CONCLUSION

Post-traumatic PE is frequent in ICUs. Inflammation acting via endothelial damage may be considered as a fourth factor in addition to the Virchow's triad of risk factors for venous thrombosis. Fractures of the lower extremities, obesity, and age happen to be the most frequent factors associated with PE (in particular early PE). PE development was associated with high rates of mortality, nosocomial infections, and a prolonged stay in an ICU and/or in a hospital. Therefore, prevention is warranted.

HIV Antivirals Affect Endothelial Activation and Endothelial-Platelet Crosstalk

RATIONALE

People living with HIV on effective antiretroviral therapy are at increased risk of cardiovascular complications, possibly due to off-target drug effects. Some studies have associated antiretroviral therapy with increased risk of myocardial infarction and endothelial dysfunction, but a link between endothelial function and antiretrovirals has not been established.

OBJECTIVE

To determine the effects of antiretrovirals in common clinical use upon in vitro endothelial function to better understand cardiovascular risk in people living with HIV.

METHODS AND RESULTS

Human umbilical cord vein endothelial cells or human coronary artery endothelial cells were pretreated with the antiretrovirals abacavir sulphate (ABC), tenofovir disoproxil fumarate, or tenofovir alafenamide. Expression of adhesion molecules, ectonucleotidases (CD39 and CD73), tissue factor (TF), endothelial-derived microparticle (EMP) numbers and phenotype, and platelet activation were evaluated by flow cytometry. TF and ectonucleotidase activities were measured using colourimetric plate-based assays. ABC-treated endothelial cells had higher levels of ICAM (intercellular adhesion molecule)-1 and TF expression following TNF (tumor necrosis factor)-α stimulation. In contrast, tenofovir disoproxil fumarate and tenofovir alafenamide treatment gave rise to greater populations of CD39⁺CD73⁺ cells. These cell surface differences were also observed within EMP repertoires. ABC-treated cells and EMP had greater TF activity, while tenofovir disoproxil fumarate- and tenofovir alafenamide-treated cells and EMP displayed higher ectonucleotidase activity. Finally, EMP isolated from ABC-treated cells enhanced collagen-evoked platelet integrin activation and α-granule release.

CONCLUSIONS

We report differential effects of antiretrovirals used in the treatment of HIV upon endothelial function. ABC treatment led to an inflammatory, prothrombotic endothelial phenotype that promoted platelet activation. In contrast, tenofovir disoproxil fumarate and tenofovir alafenamide conferred potentially cardioprotective properties associated with ectonucleotidase activity. These observations establish a link between antiretrovirals and specific functional effects that provide insight into cardiovascular disease in people living with HIV.

Modelling the linkage between influenza infection and cardiovascular events via thrombosis

There is a heavy burden associated with influenza including all-cause hospitalization as well as severe cardiovascular and cardiorespiratory events. Influenza associated cardiac events have been linked to multiple biological pathways in a human host. To study the contribution of influenza virus infection to cardiovascular thrombotic events, we develop a dynamic model which incorporates some key elements of the host immune response, inflammatory response, and blood coagulation. We formulate these biological systems and integrate them into a cohesive modelling framework to show how blood clotting may be connected to influenza virus infection. With blood clot formation inside an artery resulting from influenza virus infection as the primary outcome of this integrated model, we demonstrate how blood clot severity may depend on circulating prothrombin levels. We also utilize our model to leverage clinical data to inform the threshold level of the inflammatory cytokine TNFα which initiates tissue factor induction and subsequent blood clotting. Our model provides a tool to explore how individual biological components contribute to blood clotting events in the presence of influenza infection, to identify individuals at risk of clotting based on their circulating prothrombin levels, and to guide the development of future vaccines to optimally interact with the immune system.

Microvascular platelet aggregation and thrombosis after subarachnoid hemorrhage: A review and synthesis

Delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH) has been associated with numerous pathophysiological sequelae, including large artery vasospasm and microvascular thrombosis. The focus of this review is to provide an overview of experimental animal model studies and human autopsy studies that explore the temporal-spatial characterization and mechanism of microvascular platelet aggregation and thrombosis following SAH, as well as to critically assess experimental studies and clinical trials highlighting preventative therapeutic options against this highly morbid pathophysiological process. Upon review of the literature, we discovered that microvascular platelet aggregation and thrombosis occur after experimental SAH across multiple species and SAH induction techniques in a similar time frame to other components of DCI, occurring in the cerebral cortex and hippocampus across both hemispheres. We discuss the relationship of these findings to human autopsy studies. In the final section of this review, we highlight the important therapeutic options for targeting microvascular platelet aggregation and thrombosis, and emphasize why therapeutic targeting of this neurovascular pathology may improve patient care. We encourage ongoing research into the pathophysiology of SAH and DCI, especially in regard to microvascular platelet aggregation and thrombosis and the translation to randomized clinical trials.

Hypoxia induced up-regulation of tissue factor is mediated through extracellular RNA activated Toll-like receptor 3-activated protein 1 signalling

Sterile Inflammation (SI), a condition where damage associated molecular patterns (DAMPs) released from dying cells, leads to TLR (Toll-like receptor) activation and triggers hypoxemia in circulation leading to venous thrombosis (VT) through tissue factor (TF) activation, but its importance under acute hypoxia (AH) remains unexplored. Thus, we hypothesized that eRNA released from dying cells under AH activates TF via the TLR3-ERK1/2-AP1 pathway, leading to VT. Animals were exposed to stimulate hypoxia for 0–24 h at standard temperature and humidity. RNaseA and DNase1 were injected immediately before exposure. TLR3 gene silencing was performed through in vivo injection of TLR3 siRNA. 80 μg/kg BW of isolated eRNA and eDNA were injected 6 h prior to sacrifice. Antigens of TF pathway were determined by ELISA and TF activity by a chromogenic assay. AH exposure significantly induced release of SI markers i.e. eRNA, eDNA, HMGB1 and upregulated TLR3, ERK1/2 (Extracellular signal-regulated kinases), AP1 (Activator Protein-1) and TF, whereas RNaseA pre-treatment diminished the effect of AH, thus inhibiting TF expression as well as activity during AH. Hence, we propose a possible mechanism of AH-induced TF activation and thrombosis where RNaseA can become the novel focal point in ameliorating therapy for AH induced thrombosis.

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Acute hypoxia exposure leads to systemic Sterile Inflammation.

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eRNA regulates upregulation of TF by activation of TLR3 pathway.

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RNase A pre-treatment ameliorates effect of acute hypoxia on coagulation.

Critical Review of Large Animal Models for Central Deep Venous Thrombosis

OBJECTIVE

To review the existing literature on large animal models of central venous thrombosis (CVT) and to evaluate its relevance in regard to the development and testing of dedicated therapeutics applicable to humans.

METHODS

A systematic literature search was conducted in PubMed and Embase. Articles describing an in vivo experimental protocol of CVT in large animals, involving the iliac vein and/or the vena cava and/or the brachiocephalic vein, were included. The primary aim of the study, animal characteristics, experimental protocol, and thrombus evaluation were recorded.

RESULTS

Thirty-eight papers describing more than 30 different protocols were included. Animals used were pigs (53%), dogs (21%), monkeys (24%), and cattle (3%). The median number of animals per study was 12. Animal sex, strain, and weight were missing in 18 studies (47%), seven studies (18%), and eight studies (21%), respectively. CVT was always induced by venous stasis: solely (55%), or in addition to hypercoagulability (37%) or endothelial damage (10%). The size of the vessel used for thrombus creation was measured in four studies (10%). Unexpected animal death occurred in nine studies (24%), ranging from 3% to 37% of the animals. Twenty-two studies (58%) in the acute phase and 31 studies in the chronic phase (82%) evaluated the presence or absence of the thrombus created, and its occlusive characteristic was reported, respectively, in five and 17 studies. Histological examination was performed in 24 studies (63%) with comparison to human thrombus in one study.

CONCLUSION

This review showed advantages and weaknesses of the existing large animal models of CVT. Future models should insist on more rigour and consistency in reporting animal characteristics, as well as evaluating and comparing the thrombus created to human thrombus.

Inhibitors of blood coagulation factor XIII

The blood coagulation factor XIII (FXIII) plays an essential role in the stabilization of fibrin clots. This factor, belonging to the class of transglutaminases, catalyzes the final step of secondary hemostasis, i.e. the crosslinking of fibrin polymers. These crosslinks protect the clots against premature fibrinolysis. Consequently, FXIII is an interesting target for the therapeutic treatment of cardiovascular diseases. In this context, inhibitors can influence FXIII in the activation process of the enzyme itself or in its catalytic activity. To date, there is no FXIII inhibitor in medical application, but several studies have been conducted in the past. These studies provided a better understanding of FXIII and identified new lead structures for FXIII inhibitors. Next to small molecule inhibitors, the most promising candidates for the development of clinically applicable FXIII inhibitors are the peptide inhibitors tridegin and transglutaminase-inhibiting Michael acceptors (TIMAs) due to their selectivity towards activated FXIII (FXIIIa). In this review, select FXIII inhibitors and their pharmacological potential are discussed.

Plasma tissue factor and immune activation are associated with carotid intima-media thickness progression in treated HIV infection

OBJECTIVES

We evaluated the roles of biomarkers of immune activation with carotid intima-media thickness (CIMT) progression in treated HIV infection.

DESIGN

Longitudinal observational study of 118 treated and virologically suppressed individuals.

METHODS

We measured biomarkers of immune activation at baseline using cryopreserved samples. CIMT was measured at baseline and longitudinally using high-resolution ultrasound. Linear regression was used to estimate biomarker associations with CIMT progression, and logistic regression was used to model plaque progression.

RESULTS

The median duration of follow-up was 2.0 years. The median annual rate of change in mean CIMT was 6.0%. Rates of progression were more rapid in the bifurcation (5.6%/year, P = 0.006) and internal (6.5%/year, P = 0.0008) than common CIMT (4.3%/year). Incident plaque occurred in 13 of the 52 individuals without baseline plaque. In multivariable adjusted analysis, plasma tissue factor and monocyte chemoattractant protein-1 were associated with more rapid common CIMT progression (0.058 mm/year, P = 0.0004 and 0.067 mm/year, P = 0.017; all estimates per doubling). CD8 T-cell count and percentage of HLA-DRCD38CD8 T cells were associated with more rapid internal CIMT progression (0.10 mm/year, P = 0.008 and 0.054 mm/year, P = 0.045). CD8 T-cell count was also associated with 0.068 mm/year more rapid mean CIMT progression (P = 0.011). Each 10% increase in CD4 T-cell count at baseline was associated with a 34% reduced odds of plaque progression (P = 0.018).

CONCLUSION

Residual immune activation and plasma tissue factor are independently associated with CIMT progression in treated HIV infection. Interventions targeting coagulation and inflammatory pathways to reduce cardiovascular disease risk in HIV merit additional investigations.

Shiga Toxin-Associated Hemolytic Uremic Syndrome: A Narrative Review

The severity of human infection by one of the many Shiga toxin-producing Escherichia coli (STEC) is determined by a number of factors: the bacterial genome, the capacity of human societies to prevent foodborne epidemics, the medical condition of infected patients (in particular their hydration status, often compromised by severe diarrhea), and by our capacity to devise new therapeutic approaches, most specifically to combat the bacterial virulence factors, as opposed to our current strategies that essentially aim to palliate organ deficiencies. The last major outbreak in 2011 in Germany, which killed more than 50 people in Europe, was evidence that an effective treatment was still lacking. Herein, we review the current knowledge of STEC virulence, how societies organize the prevention of human disease, and how physicians treat (and, hopefully, will treat) its potentially fatal complications. In particular, we focus on STEC-induced hemolytic and uremic syndrome (HUS), where the intrusion of toxins inside endothelial cells results in massive cell death, activation of the coagulation within capillaries, and eventually organ failure.

Low Systemic Levels of Chemokine C-C Motif Ligand 3 (CCL3) are Associated with a High Risk of Venous Thromboembolism in Patients with Glioma

A tight interplay between inflammation and hemostasis has been described as a potential driver for developing venous thromboembolism (VTE). Here, we investigated the association of systemic cytokine levels and risk of VTE in patients with glioma. This analysis was conducted within the prospective, observational Vienna Cancer and Thrombosis Study. Patients with glioma were included at time of diagnosis or progression and were observed for a maximum of two years. Primary endpoint was objectively confirmed VTE. At study entry, a single blood draw was performed. A panel of nine cytokines was measured in serum samples with the xMAP technology developed by Luminex. Results: Overall, 76 glioma patients were included in this analysis, and 10 (13.2%) of them developed VTE during the follow-up. Chemokine C-C motif ligand 3 (CCL3) levels were inversely associated with risk of VTE (hazard ratio [HR] per double increase, 95% confidence interval [CI]: 0.385, 95% CI: 0.161–0.925, p = 0.033), while there was no association between the risk of VTE and serum levels of interleukin (IL)-1β, IL-4, IL-6, IL-8, IL-10, IL-11, tumor necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF), respectively. In conclusion, low serum levels of CCL3 were associated with an increased risk of VTE. CCL3 might serve as a potential biomarker to predict VTE risk in patients with glioma.

Evidence of epigenetic alterations in thrombosis and coagulation: A systematic review

Thrombosis in the context of Cardiovascular disease (CVD) affects mainly the blood vessels supplying the heart, brain and peripheries and it is the leading cause of death worldwide. The pathophysiological thrombotic mechanisms are largely unknown. Heritability contributes to a 30% of the incidence of CVD. The remaining variation can be explained by life style factors such as smoking, dietary and exercise habits, environmental exposure to toxins, and drug usage and other comorbidities. Epigenetic variation can be acquired or inherited and constitutes an interaction between genes and the environment. Epigenetics have been implicated in atherosclerosis, ischemia/reperfusion damage and the cardiovascular response to hypoxia. Epigenetic regulators of gene expression are mainly the methylation of CpG islands, histone post translational modifications (PTMs) and microRNAs (miRNAs). These epigenetic regulators control gene expression either through activation or silencing. Epigenetic control is mostly dynamic and can potentially be manipulated to prevent or reverse the uncontrolled expression of genes, a trait that renders them putative therapeutic targets. In the current review, we systematically studied and present available data on epigenetic alterations implicated in thrombosis derived from human studies. Evidence of epigenetic alterations is observed in several thrombotic diseases such as Coronary Artery Disease and Cerebrovascular Disease, Preeclampsia and Antiphospholipid Syndrome. Differential CpG methylation and specific histone PTMs that control transcription of prothrombotic and proinflammatory genes have also been associated with predisposing factors of thrombosis and CVD, such us smoking, air pollution, hypertriglyceridemia, occupational exposure to particulate matter and comorbidities including cancer, Chronic Obstructive Pulmonary Disease and Chronic Kidney Disease. These clinical observations are further supported by in vitro experiments and indicate that epigenetic regulation affects the pathophysiology of thrombotic disorders with potential diagnostic or therapeutic utility.

Enhancement of Tissue Factor Expression in Monocyte-Derived Dendritic Cells by Pentraxin 3 and Its Modulation by C1 Esterase Inhibitor

BACKGROUND

We have previously shown that human monocyte-derived dendritic cells (moDCs) may participate in immune system-mediated hypercoagulable state through enhanced tissue factor (TF) expression and that the complement system may be involved in this process.

OBJECTIVES

The aim of this study was to explore the role of pentraxin 3 (PTX3) and the complement system in enhanced TF expression in moDCs.

METHODS

moDCs were generated from isolated human monocytes. PTX3 levels in whole human blood supplemented with moDCs were determined after lipopolysaccharide (LPS) stimulation. PTX3 release by the generated moDCs upon LPS stimulation was also assessed. The effect of PTX3 on whole blood coagulation was investigated using thromboelastometric analysis. TF expression in stationary moDCs treated with LPS and/or PTX3 was determined by measuring TF activity. The effect of complement inhibitors on TF activity in moDCs treated with LPS and/or PTX3 under low-shear conditions was evaluated.

RESULTS

PTX3 levels were higher in whole blood supplemented with moDCs than in the presence of monocytes and were further elevated by LPS stimulation. PTX3 release from generated moDCs was also increased by LPS stimulation. PTX3 reduced whole blood coagulation time in a dose-dependent manner. However, PTX3 did not increase TF expression in stationary moDCs. Under low-shear conditions, PTX3 increased TF expression in moDCs. C1 esterase inhibitor (C1-inh) suppressed this effect.

CONCLUSIONS

PTX3 might have a thrombophilic activity and enhance TF expression in moDCs under low-shear conditions. Furthermore, suppression of moDC-associated hypercoagulability by C1-inh might be partly ascribed to its inhibitory effect on PTX3.

Early diagnosis of cerebral thrombosis by EGFP–EGF1 protein conjugated ferroferric oxide magnetic nanoparticles

Cerebral thrombosis disease is a worldwide problem, with high rates of morbidity, disability, and mortality. Magnetic resonance imaging diffusion-weighted imaging was used as an important early diagnostic method for cerebral thrombotic diseases; however, its diagnosis time is 2 h after onset. In this study, we designed EGFP–EGF1–NP–Fe3O4 for earlier diagnosis of cerebral thrombosis by taking advantage of EGFP–EGF1 fusion protein, in which EGF1 can bind with tissue factor and enhanced green fluorescent protein has previously been widely used as a fluorescent protein marker. EGFP–EGF1–NP–Fe3O4 or NP–Fe3O4 reaches the highest concentration in the infarction areas in 1 h. To evaluate the targeting ability of EGFP–EGF1–NP–Fe3O4, a fluorochrome dye, Dir, was loaded into the nanoparticle. As shown by the in vivo organ multispectral fluorescence imaging, Dir-loaded EGFP–EGF1–NP–Fe3O4 exhibited higher fluorescence than those of model rats treated with Dir-loaded NP–Fe3O4. Coronal frozen sections and transmission electron microscope further showed that EGFP–EGF1–NP–Fe3O4 was mainly accumulated in the tissue factor exposure region of brain. The data indicated that the EGFP–EGF1–NP–Fe3O4 targeted cerebral thrombosis and might be applied in the early diagnosis of intracranial thrombosis.

Anti-thrombotic effect of a factor Xa inhibitor TAK-442 in a rabbit model of arteriovenous shunt thrombosis stimulated with tissue factor

Objective

Arterial thrombosis is triggered by tissue factor, which is a transmembrane glycoprotein can be released into the blood circulation after plaque rupture. Animal models with reflecting ruptured plaque lesions will be useful to understand efficacy of anticoagulant. In this study, we sought to improve a common arteriovenous shunt model in rabbits, aiming for a model of thrombosis stimulated with tissue factor, and to investigate the anti-thrombotic effect of a direct factor Xa inhibitor TAK-442 in the model.

Results

In the model where thrombus was stimulated with a thrombogenic silk thread soaked with recombinant human tissue factor, thrombus formation was significantly reduced by TAK-442 at more than 37.5 µg/kg, accompanied with prolonged plasma hemostatic parameters. Although efficacious doses of anti-coagulants in ordinary arteriovenous thrombosis models are widely reported to be higher than those in venous thrombosis models, TAK-442 showed its efficacy in the present arteriovenous shunt thrombosis model, with equivalent sensitivity in a previously reported venous model. TAK-442 might be effective under conditions thrombus formed is more influenced by tissue factor pathway.

Mitochondrial Dysfunction in Stroke: Implications of Stem Cell Therapy

Stroke is a debilitating condition which is also the second leading cause of death and disability worldwide. Despite the benefits and promises shown by numerous neuroprotective agents in animal stroke models, their clinical translation has not been a complete success. Hence, search for treatment options have directed researchers towards utilising stem cells. Mitochondria has a major involvement in the pathophysiology of stroke and a number of other conditions. Stem cells have shown the ability to transfer mitochondria to the damaged cells and to help revive cell energetics in the recipient cell. The present review discusses how stem cells could be employed to protect neurons and mitochondria in stroke and also the various mechanisms involved in neuroprotection.

microRNAs in the haemostatic system: More than witnesses of thromboembolic diseases?

MicroRNAs (miRNAs) are small endogenous RNAs that post-transcriptionally regulate gene expression. In the last few years, these molecules have been implicated in the regulation of haemostasis, and an increasing number of studies have investigated their relationship with the development of thrombosis. In this review, we discuss the latest developments regarding the role of miRNAs in the regulation of platelet function and secondary haemostasis. We also discuss the genetic and environmental factors that regulate miRNAs. Finally, we address the potential use of miRNAs as prognostic and diagnostic tools in thrombosis.

Tissue Factor: An Essential Mediator of Hemostasis and Trigger of Thrombosis

Tissue factor (TF) is the high-affinity receptor and cofactor for factor (F)VII/VIIa. The TF-FVIIa complex is the primary initiator of blood coagulation and plays an essential role in hemostasis. TF is expressed on perivascular cells and epithelial cells at organ and body surfaces where it forms a hemostatic barrier. TF also provides additional hemostatic protection to vital organs, such as the brain, lung, and heart. Under pathological conditions, TF can trigger both arterial and venous thrombosis. For instance, atherosclerotic plaques contain high levels of TF on macrophage foam cells and microvesicles that drives thrombus formation after plaque rupture. In sepsis, inducible TF expression on monocytes leads to disseminated intravascular coagulation. In cancer patients, tumors release TF-positive microvesicles into the circulation that may contribute to venous thrombosis. TF also has nonhemostatic roles. For instance, TF-dependent activation of the coagulation cascade generates coagulation proteases, such as FVIIa, FXa, and thrombin, which induce signaling in a variety of cells by cleavage of protease-activated receptors. This review will focus on the roles of TF in protective hemostasis and pathological thrombosis.