Thrombomodulin and its role in inflammation

Group XIV C-type lectins: emerging targets in tumor angiogenesis

C-type lectins, distinguished by a C-type lectin binding domain (CTLD), are an evolutionarily conserved superfamily of glycoproteins that are implicated in a broad range of physiologic processes. The group XIV subfamily of CTLDs are comprised of CD93, CD248/endosialin, CLEC14a, and thrombomodulin/CD141, and have important roles in creating and maintaining blood vessels, organizing extracellular matrix, and balancing pro- and anti-coagulative processes. As such, dysregulation in the expression and downstream signaling pathways of these proteins often lead to clinically relevant pathology. Recently, group XIV CTLDs have been shown to play significant roles in cancer progression, namely tumor angiogenesis and metastatic dissemination. Interest in therapeutically targeting tumor vasculature is increasing and the search for novel angiogenic targets is ongoing. Group XIV CTLDs have emerged as key moderators of tumor angiogenesis and metastasis, thus offering substantial therapeutic promise for the clinic. Herein, we review our current knowledge of group XIV CTLDs, discuss each's role in malignancy and associated potential therapeutic avenues, briefly discuss group XIV CTLDs in the context of two other relevant lectin families, and offer future direction in further elucidating mechanisms by which these proteins function and facilitate tumor growth.

New Directions in Infection-Associated Ischemic Stroke

The relationship between infections and stroke has not been fully characterized, probably delaying the development of specific treatments. This narrative review addresses mechanisms of stroke linked to infections, including hypercoagulability, endothelial dysfunction, vasculitis, and impaired thrombolysis. SARS-CoV-2, the virus that causes COVID-19, may promote the development of stroke, which may represent its most severe neurological complication. The development of specific therapies for infection-associated stroke remains a profound challenge. Perhaps the most important remaining issue is the distinction between infections that trigger a stroke versus infections that are truly incidental. This distinction likely requires the establishment of appropriate biomarkers, candidates of which are elevated levels of fibrin D-dimer and anticardiolipin/antiphospholipid antibodies. These candidate biomarkers might have potential use in identifying pathogenic infections preceding stroke, which is a precursor to establishing specific therapies for this syndrome.

The Association between Coagulation and Atrial Fibrillation

The existing literature highlights the presence of numerous coagulation factors and markers. Elevated levels of coagulation factors are associated with both existing and newly diagnosed cases of atrial fibrillation (AF). However, this article summarizes the role of coagulation in the pathogenesis of AF, which includes fibrinogen and fibrin, prothrombin, thrombomodulin, soluble urokinase plasminogen activator receptor, von Willebrand factor, P-selectin, D-dimer, plasminogen activator inhibitor-1, and platelet activation. Coagulation irregularities play a significant role in the pathogenesis of AF.

Activation of cGAS-STING signaling pathway promotes liver fibrosis and hepatic sinusoidal microthrombosis

Inflammation plays an essential role in the development liver fibrosis.The Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) is a central cytoplasmic DNA sensor which can recognize cytoplasmic DNA, known to trigger stimulator of interferon genes (STING) and downstream proinflammatory factors. Here, we investigated the role of cGAS-STING signaling pathway in the pathogenesis of liver fibrosis.Differentially expressed genes (DEGs) in human liver tissue were identified using RNA-Seq analysis. As models of liver fibrosis, chronic Carbon tetrachloride (CCl4) exposure were applied in cGAS-knockout mice. LX-2 cells were co-cultured with human liver sinusoidal endothelial cells (LSECs) to explore the underlying mechanisms of hepatic sinusoidal microthrombosis in an inflammatory microenvironment. The endoscopic ultrasound-guided portal vein pressure gradient (EUS-PPG) method was used to analyze the associations between hepatic sinusoidal microthrombosis and PPG in patients with liver fibrosis and portal hypertension (PTH). The RNA-seq analysis results showed that DEGs were enriched in inflammation and endothelial cell activation. The upregulation of the cGAS-STING signaling exacerbated liver fibrosis and intrahepatic inflammation. It also exacerbated LSECs impairment and increased the contribution of hepatic sinusoidal microthrombosis to liver fibrosis in vivo and in vitro. Prothrombotic mediators and proinflammatory factors were associated with PPG in patients with liver fibrosis and portal hypertension. Therefore, activating cGAS-STING signaling pathway promotes liver fibrosis and hepatic sinusoidal microthrombosis, which may lead to increased portal vein pressure.

Metabolic syndrome, soluble CD40L, and biomarkers of endothelial dysfunction in people living with HIV

In the present study, we aimed to investigate the association between soluble CD40 ligand (sCD40L, a marker of platelet activation), soluble thrombomodulin, and syndecan-1 (both well-described markers of endothelial dysfunction) and metabolic syndrome in a large cohort of well-treated people with HIV (PWH) and to elucidate their association with HIV-specific variables. We included 862 PWH with undetectable viral replication. Our hypotheses were tested using uni- and multivariable logistic regression models a priori adjusted for well-known confounders. While no association of soluble thrombomodulin and syndecan-1 with MetS was found, high levels of sCD40L (aOR 1.54 [1.07-2.22]) were associated with excess risk of MetS. Given the previously described association between sCD40L, vascular inflammation and endothelial damage, the results presented in our study may suggest a potential role for sCD40L in the well-known association between cardiometabolic comorbidity and HIV infection.

VEGFR and DPP-IV as Markers of Severe COVID-19 and Predictors of ICU Admission

The pathophysiology of the severe course of COVID-19 is multifactorial and not entirely elucidated. However, it is well known that the hyperinflammatory response and cytokine storm are paramount events leading to further complications. In this paper, we investigated the vascular response in the pathophysiology of severe COVID-19 and aimed to identify novel biomarkers predictive of ICU admission. The study group consisted of 210 patients diagnosed with COVID-19 (age range: 18-93; mean ± SD: 57.78 ± 14.16), while the control group consisted of 80 healthy individuals. We assessed the plasma concentrations of various vascular factors using the Luminex technique. Then, we isolated RNA from blood mononuclear cells and performed a bioinformatics analysis investigating various processes related to vascular response, inflammation and angiogenesis. Our results confirmed that severe COVID-19 is associated with vWF/ADAMTS 13 imbalance. High plasma concentrations of VEGFR and low DPP-IV may be potential predictors of ICU admission. SARS-CoV-2 infection impairs angiogenesis, hinders the generation of nitric oxide, and thus impedes vasodilation. The hypercoagulable state develops mainly in the early stages of the disease, which may contribute to the well-established complications of COVID-19.

The in vitro effect of anticoagulant agents on coagulation and fibrinolysis in the presence of emicizumab in the plasmas from patients with haemophilia A

INTRODUCTION

Emicizumab is used as hemostatic prophylaxis for patients with hemophilia A (PwHA), irrespective of the presence of inhibitors. Although bacterial infection can lead to a procoagulant state, there is limited information on coagulation and fibrinolysis potentials in emicizumab-treated PwHA and on the use of anticoagulants in such cases.

AIM

We examined whether anticoagulants affect the coagulation and fibrinolysis potentials in plasma from PwHA spiked with emicizumab.

METHODS

Plasma from PwHA was in vitro supplemented with emicizumab (50 μg/mL; emi-plasma) and anticoagulants (recombinant thrombomodulin (rTM), nafamostat mesylate (NM), unfractionated heparin (UFH), or low-molecular-weight heparin (LMH)). PwHA plasma spiked with rFVIII (1 IU/mL) was used as a reference (ref-plasma). The coagulation and fibrinolysis potentials in plasma was measured by thrombin and plasmin generation assay (T/P-GA) and clot-fibrinolysis waveform analysis (CFWA).

RESULTS

In T/P-GA and CFWA, coagulation potentials (maximum coagulation velocity; |min1|, and peak thrombin; Th-Peak) in plasma rose with increasing concentrations of emicizumab and rFVIII, but fibrinolytic potentials (peak plasmin; Plm-Peak, and maximum fibrinolytic velocity; |FL-min1|) remained unchanged. Adding rTM, NM, and UFH to emi-plasma suppressed coagulation and fibrinolysis potentials, similar to ref-plasma. Regarding the heparin, UFH and LMH inhibited the improved coagulation in emi-plasma. UFH inhibited fibrinolysis as well, but LMH did not.

CONCLUSIONS

Anticoagulants could exhibit the inhibitory effects on the coagulation and fibrinolysis potentials in plasma from PwHA spiked with emicizumab, similar to those in normal plasma.

Pregnancy by Oocyte Donation: Reviewing Fetal-Maternal Risks and Complications

Oocyte donation (OD) has greatly improved over the last three decades, becoming a preferred practice of assisted reproductive technology (ART) for infertile women wishing for motherhood. Through OD, indeed, it has become possible to overcome the physiological limitation due to the ovarian reserve (OR) exhaustion as well as the poor gamete reliability which parallels the increasing age of women. However, despite the great scientific contribution related to the success of OD in the field of infertility, this practice seems to be associated with a higher rate of major risky events during pregnancy as recurrent miscarriage, infections and placental diseases including gestational hypertension, pre-eclampsia and post-partum hemorrhage, as well as several maternal-fetal complications due to gametes manipulation and immune system interaction. Here, we will revisit this questioned topic since a number of studies in the medical literature focus on the successful aspects of the OD procedure in terms of pregnancy rate without, however, neglecting the risks and complications potentially linked to external manipulation or heterologous implantation.

Matrix stiffness regulates neovascular homeostasis through autophagy in nude mice

One of the major obstacles to the effective application of vascularized fruit is an insufficient understanding of the relationship between the microenvironment and neovascular homeostasis. The role of extracellular matrix stiffness in regulating the structural and functional stability of neovascularization has not yet been elucidated. This study explored the effects of matrix stiffness on neovascular homeostasis in nude mice. Dextran hydrogels with three different stiffnesses were separately combined with mouse bone marrow-derived endothelial progenitor cells (EPCs) and subcutaneously implanted into the backs of nude mice. After 14 days, neovascular homeostasis indicators in the different groups were measured. Cell autophagy levels were evaluated, and inhibitor assays were performed to explore the underlying mechanism. New blood vessels were generated in the three stiffnesses of the EPC-loaded dextran hydrogels 14 days after implantation. The newly formed vessels tended to have better structural stability in softer hydrogels. Endothelial function markers, such as endothelial nitric oxide synthase and E-selectin, were downregulated as the matrix stiffness increased. Furthermore, we found that cell autophagy levels decreased in stiffer matrices, and autophagy inhibition attenuated neovascular homeostasis. A soft matrix is conducive to maintaining neovascular homeostasis through autophagy in nude mice.

A Scoping Review on Biomarkers of Endothelial Dysfunction in Small Vessel Disease: Molecular Insights from Human Studies

Small vessel disease (SVD) is a highly prevalent disorder of the brain's microvessels and a common cause of dementia as well as ischaemic and haemorrhagic strokes. Though much about the underlying pathophysiology of SVD remains poorly understood, a wealth of recently published evidence strongly suggests a key role of microvessel endothelial dysfunction and a compromised blood-brain barrier (BBB) in the development and progression of the disease. Understanding the causes and downstream consequences associated with endothelial dysfunction in this pathological context could aid in the development of effective diagnostic and prognostic tools and provide promising avenues for potential therapeutic interventions. In this scoping review, we aim to summarise the findings from clinical studies examining the role of the molecular mechanisms underlying endothelial dysfunction in SVD, focussing on biochemical markers of endothelial dysfunction detectable in biofluids, including cell adhesion molecules, BBB transporters, cytokines/chemokines, inflammatory markers, coagulation factors, growth factors, and markers involved in the nitric oxide cascade.

HMGB1: a double-edged sword and therapeutic target in the female reproductive system

HMGB1 that belongs to the High Mobility Group-box superfamily, is a nonhistone chromatin associated transcription factor. It is present in the nucleus of eukaryotes and can be actively secreted or passively released by kinds of cells. HMGB1 is important for maintaining DNA structure by binding to DNA and histones, protecting it from damage. It also regulates the interaction between histones and DNA, affecting chromatin packaging, and can influence gene expression by promoting nucleosome sliding. And as a DAMP, HMGB1 binding to RAGE and TLRs activates NF-κB, which triggers the expression of downstream genes like IL-18, IL-1β, and TNF-α. HMGB1 is known to be involved in numerous physiological and pathological processes. Recent studies have demonstrated the significance of HMGB1 as DAMPs in the female reproductive system. These findings have shed light on the potential role of HMGB1 in the pathogenesis of diseases in female reproductive system and the possibilities of HMGB1-targeted therapies for treating them. Such therapies can help reduce inflammation and metabolic dysfunction and alleviate the symptoms of reproductive system diseases. Overall, the identification of HMGB1 as a key player in disease of the female reproductive system represents a significant breakthrough in our understanding of these conditions and presents exciting opportunities for the development of novel therapies.

Chondrocyte Thrombomodulin Protects against Osteoarthritis

Osteoarthritis (OA) is a prevalent form of arthritis that affects over 32.5 million adults worldwide, causing significant cartilage damage and disability. Unfortunately, there are currently no effective treatments for OA, highlighting the need for novel therapeutic approaches. Thrombomodulin (TM), a glycoprotein expressed by chondrocytes and other cell types, has an unknown role in OA. Here, we investigated the function of TM in chondrocytes and OA using various methods, including recombinant TM (rTM), transgenic mice lacking the TM lectin-like domain (TM^LeD/LeD), and a microRNA (miRNA) antagomir that increased TM expression. Results showed that chondrocyte-expressed TM and soluble TM [sTM, like recombinant TM domain 1 to 3 (rTMD123)] enhanced cell growth and migration, blocked interleukin-1β (IL-1β)-mediated signaling and protected against knee function and bone integrity loss in an anterior cruciate ligament transection (ACLT)-induced mouse model of OA. Conversely, TM^LeD/LeD mice exhibited accelerated knee function loss, while treatment with rTMD123 protected against cartilage loss even one-week post-surgery. The administration of an miRNA antagomir (miR-up-TM) also increased TM expression and protected against cartilage damage in the OA model. These findings suggested that chondrocyte TM plays a crucial role in counteracting OA, and miR-up-TM may represent a promising therapeutic approach to protect against cartilage-related disorders.

Cell-Specific Mechanisms in the Heart of COVID-19 Patients

From the onset of the pandemic, evidence of cardiac involvement in acute COVID-19 abounded. Cardiac presentations ranged from arrhythmias to ischemia, myopericarditis/myocarditis, ventricular dysfunction to acute heart failure, and even cardiogenic shock. Elevated serum cardiac troponin levels were prevalent among hospitalized patients with COVID-19; the higher the magnitude of troponin elevation, the greater the COVID-19 illness severity and in-hospital death risk. Whether these consequences were due to direct SARS-CoV-2 infection of cardiac cells or secondary to inflammatory responses steered early cardiac autopsy studies. SARS-CoV-2 was reportedly detected in endothelial cells, cardiac myocytes, and within the extracellular space. However, findings were inconsistent and different methodologies had their limitations. Initial autopsy reports suggested that SARS-CoV-2 myocarditis was common, setting off studies to find and phenotype inflammatory infiltrates in the heart. Nonetheless, subsequent studies rarely detected myocarditis. Microthrombi, cardiomyocyte necrosis, and inflammatory infiltrates without cardiomyocyte damage were much more common. In vitro and ex vivo experimental platforms have assessed the cellular tropism of SARS-CoV-2 and elucidated mechanisms of viral entry into and replication within cardiac cells. Data point to pericytes as the primary target of SARS-CoV-2 in the heart. Infection of pericytes can account for the observed pericyte and endothelial cell death, innate immune response, and immunothrombosis commonly observed in COVID-19 hearts. These processes are bidirectional and synergistic, rendering a definitive order of events elusive. Single-cell/nucleus analyses of COVID-19 myocardial tissue and isolated cardiac cells have provided granular data about the cellular composition and cell type-specific transcriptomic signatures of COVID-19 and microthrombi-positive COVID-19 hearts. Still, much remains unknown and more in vivo studies are needed. This review seeks to provide an overview of the current understanding of COVID-19 cardiac pathophysiology. Cell type-specific mechanisms and the studies that provided such insights will be highlighted. Given the unprecedented pace of COVID-19 research, more mechanistic details are sure to emerge since the writing of this review. Importantly, our current knowledge offers significant clues about the cardiac pathophysiology of long COVID-19, the increased postrecovery risk of cardiac events, and thus, the future landscape of cardiovascular disease.

DNA methylation changes and increased mRNA expression of coagulation proteins, factor V and thrombomodulin in Fuchs endothelial corneal dystrophy

Late-onset Fuchs endothelial corneal dystrophy (FECD) is a disease affecting the corneal endothelium (CE), associated with a cytosine-thymine-guanine repeat expansion at the CTG18.1 locus in the transcription factor 4 (TCF4) gene. It is unknown whether CTG18.1 expansions affect global methylation including TCF4 gene in CE or whether global CE methylation changes at advanced age. Using genome-wide DNA methylation array, we investigated methylation in CE from FECD patients with CTG18.1 expansions and studied the methylation in healthy CE at different ages. The most revealing DNA methylation findings were analyzed by gene expression and protein analysis. 3488 CpGs had significantly altered methylation pattern in FECD though no substantial changes were found in TCF4. The most hypermethylated site was in a predicted promoter of aquaporin 1 (AQP1) gene, and the most hypomethylated site was in a predicted promoter of coagulation factor V (F5 for gene, FV for protein). In FECD, AQP1 mRNA expression was variable, while F5 gene expression showed a ~ 23-fold increase. FV protein was present in both healthy and affected CE. Further gene expression analysis of coagulation factors interacting with FV revealed a ~ 34-fold increase of thrombomodulin (THBD). THBD protein was detected only in CE from FECD patients. Additionally, we observed an age-dependent hypomethylation in elderly healthy CE.Thus, tissue-specific genome-wide and gene-specific methylation changes associated with altered gene expression were discovered in FECD. TCF4 pathological methylation in FECD because of CTG18.1 expansion was ruled out.

Sepsis-Induced Coagulopathy: An Update on Pathophysiology, Biomarkers, and Current Guidelines

Significant cross talk occurs between inflammation and coagulation. Thus, coagulopathy is common in sepsis, potentially aggravating the prognosis. Initially, septic patients tend to exhibit a prothrombotic state through extrinsic pathway activation, cytokine-induced coagulation amplification, anticoagulant pathways suppression, and fibrinolysis impairment. In late sepsis stages, with the establishment of disseminated intravascular coagulation (DIC), hypocoagulability ensues. Traditional laboratory findings of sepsis, including thrombocytopenia, increased prothrombin time (PT) and fibrin degradation products (FDPs), and decreased fibrinogen, only present late in the course of sepsis. A recently introduced definition of sepsis-induced coagulopathy (SIC) aims to identify patients at an earlier stage when changes to coagulation status are still reversible. Nonconventional assays, such as the measurement of anticoagulant proteins and nuclear material levels, and viscoelastic studies, have shown promising sensitivity and specificity in detecting patients at risk for DIC, allowing for timely therapeutic interventions. This review outlines current insights into the pathophysiological mechanisms and diagnostic options of SIC.

A missense mutation in lectin domain of thrombomodulin causing functional deficiency

Thrombomodulin (TM) functions in coagulation, fibrinolysis and inflammation by its cofactor activity for protein C, thrombin-activatable fibrinolysis inhibitor (TAFI) activation and high mobility group box 1 (HMGB1) degradation induced by thrombin. It has been widely reported that mutations in TM are related to thromboembolic diseases but hardly in lectin domain. Here we report our findings about the functional deficiencies in TM caused by substitution of aspartate with tyrosine at residue 126. Three patients suffering from recurrent thromboembolic diseases were identified with this mutation and their plasma soluble TM levels were decreased. Transfected cells expressing wild-type TM or the variant and corresponding proteins were used to examine TM functions in vitro. The cofactor activity of the mutant for protein C, TAFI activation was reduced to approximately 50% and 60% respectively. Loss in anti-inflammation due to weakened HMGB1 degradation was also observed. And the study with thrombosis models of mice suggested the decreased inhibition of thrombus development of the mutant. Together the results showed deleterious changes on TM function caused by this mutation, which may explain the thrombophilia tendency of the patients. This work provided supportive evidence that mutation in lectin domain of TM might be related to thrombotic diseases and may help us better understand the physiological roles of TM.

Recombinant Human Thrombomodulin Reduces Mortality and Acute Lung Injury Caused by Septic Peritonitis in Rats

This study aimed to investigate the therapeutic effects of recombinant human thrombomodulin (rhTM) on acute lung injury (ALI) caused by sepsis in rats. Rats that underwent cecal ligation and puncture (CLP) were treated with or without rhTM, and then mortality was analyzed. In another set of experiments, ALI was assessed. Furthermore, microthrombosis in the lungs was investigated by immunohistochemistry. Moreover, plasma inflammatory and anti-inflammatory cytokines, such as TNF-α, high-mobility group box chromosomal protein 1 (HMGB-1), and IL-10, were evaluated by ELISA. Production of TNF-α and HMGB-1 by isolated tissue macrophages (Mφs) was assessed in vitro. Mortality after CLP was significantly improved by rhTM treatment. In addition, rhTM treatment improved the wet/dry weight ratio of the lungs, the pulmonary microvascular permeability, and the lung injury scores in animals that underwent CLP. Microthrombosis was detected in the lungs after CLP. These pathophysiological changes were blunted by rhTM treatment. Increased plasma TNF-α and HMGB-1 levels were blunted by rhTM treatment; however, the anti-inflammatory cytokine IL-10 was significantly greater in the rhTM(+) group than in the rhTM(-) group. Increased TNF-α and HMGB-1 production by the tissue Mφs stimulated with LPS were significantly blunted by rhTM treatment in vitro, but the production of IL-10 by the tissue Mφs was not changed in the cells incubated with rhTM. Overall, rhTM improved the mortality caused by septic peritonitis. The possible mechanisms are most likely anti-inflammatory and anticoagulant effects, which lead to the prevention of ALI.

Fibroblast growth factor-2 bound to specific dermal fibroblast-derived extracellular vesicles is protected from degradation

Fibroblast growth factor-2 (FGF2) has multiple roles in cutaneous wound healing but its natural low stability prevents the development of its use in skin repair therapies. Here we show that FGF2 binds the outer surface of dermal fibroblast (DF)-derived extracellular vesicles (EVs) and this association protects FGF2 from fast degradation. EVs isolated from DF cultured in the presence of FGF2 harbor FGF2 on their surface and FGF2 can bind purified EVs in absence of cells. Remarkably, FGF2 binding to EVs is restricted to a specific subpopulation of EVs, which do not express CD63 and CD81 markers. Treatment of DF with FGF2-EVs activated ERK and STAT signaling pathways and increased cell proliferation and migration. Local injection of FGF2-EVs improved wound healing in mice. We further demonstrated that binding to EVs protects FGF2 from both thermal and proteolytic degradation, thus maintaining FGF2 function. This suggests that EVs protect soluble factors from degradation and increase their stability and half-life. These results reveal a novel aspect of EV function and suggest EVs as a potential tool for delivering FGF2 in skin healing therapies.

Hemostasis Proteins in Invasive Meningococcal and Nonmeningococcal Infections: A Prospective Multicenter Study

OBJECTIVES

We aimed to describe the variation of hemostasis proteins in children with bacterial infections due to different pathogens ( Neisseria meningitidis, Streptococcus pneumoniae, Staphylococcus aureus , and group A streptococcus [GAS]) and to study hemostasis proteins in relation to mortality.

DESIGN

Preplanned analysis in prospective cohort study.

SETTING

Hospitals in five European countries (Austria, The Netherlands, Spain, Switzerland, and the United Kingdom).

PATIENTS

Admitted children (2012-2016) with community-acquired infections due to meningococci ( n = 83), pneumococci ( n = 64), S. aureus (n = 50), and GAS ( n = 44) with available serum samples collected less than 48 hours after admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Fibronectin, plasminogen activator inhibitor type 1 (PAI-1), thrombomodulin, and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13) were measured in serum in 2019-2020. Additionally, von Willebrand factor, protein C, protein S, and factor IX were measured in citrate plasma available from a subset of patients. Outcome measures included in-hospital mortality and disease severity (need for ventilation/inotropes, Pediatric Index of Mortality score).Of 241 children, 21 (8.7%) died and 177 (73.5%) were admitted to PICU. Mortality rate was similar for the pathogen groups. Levels of fibronectin and thrombomodulin differed for the different pathogens ( p < 0.05). Fibronectin levels were lower in GAS infections than in S. pneumoniae and S. aureus infections but did not differ from meningococcal infections. Thrombomodulin levels in meningococcal infections were higher than in S. aureus and pneumococcal infections. Overall, the area under the curve for mortality was 0.81 (95% CI, 0.70-0.92) for thrombomodulin and 0.78 (95% CI, 0.69-0.88) for ADAMTS-13. The association of each hemostasis protein did not vary across pathogens for any of the outcome measures.

CONCLUSIONS

Hemostatic disturbances in childhood bacterial infections are not limited to meningococcal sepsis but occur with a comparable severity across nonmeningococcal infections. High thrombomodulin and high ADAMTS-13 had good discriminative ability for mortality. Our results emphasize the importance of hemostatic disturbances in meningococcal and nonmeningococcal pediatric bacterial infections.

Regulation of VWF (Von Willebrand Factor) in Inflammatory Thrombosis

Increasing evidence indicates that inflammation promotes thrombosis via a VWF (von Willebrand factor)-mediated mechanism. VWF plays an essential role in maintaining the balance between blood coagulation and bleeding, and inflammation can lead to aberrant regulation. VWF is regulated on a transcriptional and (post-)translational level, and its secretion into the circulation captures platelets upon endothelial activation. The significant progress that has been made in understanding transcriptional and translational regulation of VWF is described in this review. First, we describe how VWF is regulated at the transcriptional and post-translational level with a specific focus on the influence of inflammatory and immune responses. Next, we describe how changes in regulation are linked with various cardiovascular diseases. Recent insights from clinical diseases provide evidence for direct molecular links between inflammation and thrombosis, including atherosclerosis, chronic thromboembolic pulmonary hypertension, and COVID-19. Finally, we will briefly describe clinical implications for antithrombotic treatment.

Advance of genetically modified pigs in xeno-transplantation

As the standard of living improves, chronic diseases and end-stage organ failure have been a regular occurrence in human beings. Organ transplantation has become one of the hopes in the fight against chronic diseases and end-stage organ failure. However, organs available for transplantation are far from sufficient to meet the demand, leading to a major organ shortage crisis. To solve this problem, researchers have turned to pigs as their target since pigs have many advantages as xenograft donors. Pigs are considered the ideal organ donor for human xenotransplantation, but direct transplantation of porcine organs to humans faces many obstacles, such as hyperacute rejection, acute humoral xenograft rejection, coagulation dysregulation, inflammatory response, coagulation dysregulation, and endogenous porcine retroviral infection. Many transgenic strategies have been developed to overcome these obstacles. This review provides an overview of current advances in genetically modified pigs for xenotransplantation. Future genetic engineering-based delivery of safe and effective organs and tissues for xenotransplantation remains our goal.

An ultrasensitive cathodic electrochemiluminescence immunoassay for thrombomodulin based on Ru(bpy)32+ encapsulated by MIL-NH2-101(Al) nanocomposites

The rapid and reliable determination of thrombomodulin (TM) is of great significance for the diagnosis of disseminated intravascular coagulation, thrombosis and others. This work exhibits an electrochemiluminescent (ECL) sensor, which was prepared using Ru(bpy)₃²⁺ encapsulated by MIL-NH₂-101(Al) nanocomposites for the sensitive detection of the new-thrombus marker thrombomodulin (TM) for the first time. Specifically, on one hand, with the advantages of high specific surface area, large hollow porous structure and favorable biocompatibility, MIL-NH₂-101(Al) could load a large amount of luminescent Ru(bpy)₃²⁺ and thereby greatly enhance the ECL signal of the immunosensor. On the other hand, K₂S₂O₈ is used as co-reactant to form a reduction-oxidation ECL system for cathodic ECL detection with strong anti-interference capacity. The experimental results show that the ECL signal intensity of the Ru(bpy)₃²⁺@MIL-NH₂-101(Al)-based immunosensor decreased with the immunocapturing of TM, exhibiting a linear detection concentration ranging from 1 × 10^-5 to 10 μg mL^-1 and the limit of detection (LOD) of 8.2 × 10^-6 μg mL^-1 (S/N = 3). With its ideal stability, selectivity and reproducibility, the proposed ECL immunosensor can provide excellent aid and shows great promise for the detection of TM.

Anticoagulation Strategies during Extracorporeal Membrane Oxygenation: A Narrative Review

The development of extracorporeal life support technology has added a new dimension to the care of critically ill patients who fail conventional treatment options. Extracorporeal membrane oxygenation (ECMO)—specialized temporary life support for patients with severe cardiac or pulmonary failure—plays a role in bridging the time for organ recovery, transplant, or permanent assistance. The overall patient outcome is dependent on the underlying disease, comorbidities, patient reaction to critical illness, and potential adverse events during ECMO. Moreover, the contact of the blood with the large artificial surface of an extracorporeal system circuit triggers complex inflammatory and coagulation responses. These processes may further lead to endothelial injury and disrupted microcirculation with consequent end-organ dysfunction and the development of adverse events like thromboembolism. Therefore, systemic anticoagulation is considered crucial to alleviate the risk of thrombosis and failure of ECMO circuit components. The gold standard and most used anticoagulant during extracorporeal life support is unfractionated heparin, with all its benefits and disadvantages. However, therapeutic anticoagulation of a critically ill patient carries the risk of clinically relevant bleeding with the potential for permanent injury or death. Similarly, thrombotic events may occur. Therefore, different anticoagulation strategies are employed, while the monitoring and the balance of procoagulant and anticoagulatory factors is of immense importance. This narrative review summarizes the most recent considerations on anticoagulation during ECMO support, with a special focus on anticoagulation monitoring and future directions.

Circulating Thrombomodulin: Release Mechanisms, Measurements, and Levels in Diseases and Medical Procedures

Thrombomodulin (TM) is a type-I transmembrane protein that is mainly expressed on endothelial cells and plays important roles in many biological processes. Circulating TM of different forms are also present in biofluids, such as blood and urine. Soluble TM (sTM), comprised of several domains of TM, is the major circulating TM which is generated by either enzymatic or chemical cleavage of the intact protein under different conditions. Under normal conditions, sTM is present in low concentrations (<10 ng/mL) in the blood but is elevated in several pathological conditions associated with endothelial dysfunction such as cardiovascular, inflammatory, infection, and metabolic diseases. Therefore, sTM level has been examined for monitoring disease development, such as disseminated intravascular coagulation (DIC), sepsis and multiple organ dysfunction syndrome in patients with novel coronavirus disease 2019 (COVID-19) recently. In addition, microvesicles (MVs) that contain membrane TM (MV-TM) have been found to be released from activated cells which also contribute to levels of circulating TM in certain diseases. Several release mechanisms of sTM and MV-TM have been reported, including enzymatic, chemical, and TM mutation mechanisms. Measurements of sTM and MV-TM have been developed and explored as biomarkers in many diseases. In this review, we summarize all these advances in three categories as follows: (1) release mechanisms of circulating TM, (2) methods for measuring circulating TM in biological samples, and (3) correlation of circulating TM with diseases. Altogether, it provides a whole picture of recent advances on circulating TM in health and disease.

A glimpse into the past: phylogenesis and protein domain analysis of the group XIV of C-type lectins in vertebrates

Background

The group XIV of C-type lectin domain-containing proteins (CTLDcps) is one of the seventeen groups of CTLDcps discovered in mammals and composed by four members: CD93, Clec14A, CD248 and Thrombomodulin, which have shown to be important players in cancer and vascular biology. Although these proteins belong to the same family, their phylogenetic relationship has never been dissected. To resolve their evolution and characterize their protein domain composition we investigated CTLDcp genes in gnathostomes and cyclostomes and, by means of phylogenetic approaches as well as synteny analyses, we inferred an evolutionary scheme that attempts to unravel their evolution in modern vertebrates.

Results

Here, we evidenced the paralogy of the group XIV of CTLDcps in gnathostomes and discovered that a gene loss of CD248 and Clec14A occurred in different vertebrate groups, with CD248 being lost due to chromosome disruption in birds, while Clec14A loss in monotremes and marsupials did not involve chromosome rearrangements. Moreover, employing genome annotations of different lampreys as well as one hagfish species, we investigated the origin and evolution of modern group XIV of CTLDcps. Furthermore, we carefully retrieved and annotated gnathostome CTLDcp domains, pointed out important differences in domain composition between gnathostome classes, and assessed codon substitution rate of each domain by analyzing nonsynonymous (Ka) over synonymous (Ks) substitutions using one representative species per gnathostome order.

Conclusions

CTLDcps appeared with the advent of early vertebrates after a whole genome duplication followed by a sporadic tandem duplication. These duplication events gave rise to three CTLDcps in the ancestral vertebrate that underwent further duplications caused by the independent polyploidizations that characterized the evolution of cyclostomes and gnathostomes. Importantly, our analyses of CTLDcps in gnathostomes revealed critical inter-class differences in both extracellular and intracellular domains, which might help the interpretation of experimental results and the understanding of differences between animal models.

Plasma Thrombomodulin Levels and Ischemic Stroke: A Population-Based Prognostic Cohort Study

BACKGROUND AND OBJECTIVES

Thrombomodulin has been suggested to be implicated in ischemic stroke due to its anticoagulant, anti-inflammatory, and cytoprotective properties. We aimed to investigate the associations of plasma thrombomodulin levels with clinical outcomes after ischemic stroke in a multicenter prognostic cohort study.

METHODS

Our multicenter prognostic cohort study included 3532 Chinese ischemic stroke patients from the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS). All patients were followed up at 3 months after ischemic stroke onset. The primary outcome was the composite outcome of death and major disability (modified Rankin scale [mRS] score ≥3) at 3 months after ischemic stroke. Secondary outcomes included major disability (mRS score, 3-5), vascular events, and the ordered 7-level categorical score of the mRS.

RESULTS

During 3 months of follow-up, 867 participants experienced primary outcome. After multivariate adjustment, the adjusted odds ratios or hazard ratios associated with highest quartile of plasma thrombomodulin were 0.75 (95% CI, 0.59-0.97; p _trend=0.029) for primary outcome, 0.73 (95% CI, 0.56-0.94; p _trend=0.028) for major disability, and 0.80 (95% CI, 0.42-1.51; p _trend=0.232) for vascular events. In addition, a significantly better shift in the distribution of mRS score was observed with higher thrombomodulin quartiles (p _trend=0.005). Multivariable-adjusted spline regression model showed a linear relationship between plasma thrombomodulin and the risk of primary outcome (p for linearity=0.027). Subgroup analyses further confirmed these associations.

DISCUSSION

Increased plasma thrombomodulin levels at baseline were associated with decreased risks of adverse clinical outcomes at 3 months after ischemic stroke, suggesting a protective role of thrombomodulin in the development of ischemic stroke. Further studies from various populations are needed to replicate our findings.

The effect of prostacyclin infusion on markers of endothelial activation and damage in mechanically ventilated patients with SARS-CoV-2 infection

Background

In a pilot study, we found a significant reduction in mean daily sequential organ failure assessment score in mechanically ventilated patients with COVID-19 who received prostacyclin, compared to placebo. We here investigate the effect on biomarkers of endothelial activation and damage.

Methods

Post-hoc study of a randomized controlled trial in adult patients with confirmed SARS-CoV-2 infection, mechanically ventilated, with soluble thrombomodulin (sTM) plasma levels >4 ng/mL. Patients received prostacyclin infusion (1 ng/kg/min) or placebo. Blood samples were collected at baseline and 24 h.

Results

Eighty patients were randomized (41 prostacyclin, 39 placebo). The median changes in syndecan-1 plasma levels at 24 h were −3.95 (IQR: −21.1 to 2.71) ng/mL in the prostacyclin group vs. 3.06 (IQR: −8.73 to 20.5) ng/mL in the placebo group (difference of the medians: -7.01 [95% CI: −22.3 to −0.231] ng/mL, corresponding to −3% [95% CI: −11% to 0%], p = 0.04). Changes in plasma levels of sTM, PECAM-1, p-selectin, and CD40L did not differ significantly between groups.

Conclusions

Prostacyclin infusion, compared to placebo, resulted in a measurable decrease in endothelial glycocalyx shedding (syndecan-1) at 24 h, suggesting a protective effect on the endothelium, which may be related to the observed reduction in organ failure.

VhH anti-thrombomodulin clone 1 inhibits TAFI activation and enhances fibrinolysis in human whole blood under flow

BACKGROUND

Thrombomodulin on endothelial cells can form a complex with thrombin. This complex has both anticoagulant properties, by activating protein C, and clot-protective properties, by activating thrombin-activatable fibrinolysis inhibitor (TAFI). Activated TAFI (TAFIa) inhibits plasmin-mediated fibrinolysis.

OBJECTIVES

TAFIa inhibition is considered a potential antithrombotic strategy. So far, this goal has been pursued by developing compounds that directly inhibit TAFIa. In contrast, we here describe variable domain of heavy-chain-only antibody (VhH) clone 1 that inhibits TAFI activation by targeting human thrombomodulin.

METHODS

Two llamas (Lama Glama) were immunized, and phage display was used to select VhH anti-thrombomodulin (TM) clone 1. Affinity was determined with surface plasmon resonance and binding to native TM was confirmed with flow cytometry. Clone 1 was functionally assessed by competition, clot lysis, and thrombin generation assays. Last, the effect of clone 1 on tPA-mediated fibrinolysis in human whole blood was investigated in a microfluidic fibrinolysis model.

RESULTS

VhH anti-TM clone 1 bound recombinant TM with a binding affinity of 1.7 ± 0.4 nM and showed binding to native TM. Clone 1 competed with thrombin for binding to TM and attenuated TAFI activation in clot lysis assays and protein C activation in thrombin generation experiments. In a microfluidic fibrinolysis model, inhibition of TM with clone 1 fully prevented TAFI activation.

DISCUSSION

We have developed VhH anti-TM clone 1, which inhibits TAFI activation and enhances tPA-mediated fibrinolysis under flow. Different from agents that directly target TAFIa, our strategy should preserve direct TAFI activation via thrombin.

The Role of Excessive Anticoagulation and Missing Hyperinflammation in ECMO-Associated Bleeding

Extracorporeal membrane oxygenation (ECMO) is increasingly used in carefully selected patients with cardiac or respiratory failure. However, complications are common and can be associated with worse outcomes, while data on risk factors and outcomes are inconsistent and sparse. Therefore, we sought to investigate potential risk factors and predictors of haemorrhage and adverse events during ECMO and its influence on mortality. We retrospectively reviewed all patients on ECMO support admitted to intensive care units of a tertiary university centre in Austria. In a period of ten years, ECMO support was used in 613 patients, with 321 patients meeting the inclusion criteria of this study. Haemorrhage, occurring in more than one third of the included patients (123, 38%), represented the most common and serious ECMO complication, being associated with an increased one year mortality (51% vs. 35%, p = 0.005). The main risk factors for haemorrhage were severity of the disease (hazard ratio (HR) = 1.01, p = 0.047), a prolonged activated partial thromboplastin time (HR = 1.01, p = 0.007), and lower values of C-reactive protein (HR = 0.96, p = 0.005) and procalcitonin (HR = 0.99, p = 0.029). In summary, haemorrhage remained the main ECMO complication with increased mortality. Moreover, we reported a possible association of lower inflammation and bleeding during ECMO support for the first time. This generated a new hypothesis that warrants further research. Finally, we recommend stricter monitoring of anticoagulation especially in patients without hyperinflammation.

Genome-wide identification of endosialin family of C-type lectins in common carp (Cyprinus carpio) and their response following Aeromonas hydrophila infection

The endosialin family is the group XIV of C-type lectin, regulating several processes involved in innate immunity and inflammation. Endosialin family genes have been extensively studied in human and mammals, however, rarely reported in teleost. In the present study, a set of 8 endosialin family genes was identified across the entire common carp genome. Functional domain and motif prediction and phylogenetic analysis supported their annotation and orthologies. Through examining gene copy number across several vertebrates, endosialin family genes were found have undergone gene duplication. Most of the endosialin family genes were ubiquitously expressed during common carp early developmental stages, and presented tissue-specific expression patterns in various healthy tissues, with relatively high expression in intestine, liver, gill, spleen and kidney, indicating their likely essential roles in maintaining homeostasis and host immune response. After Aeromonas hydrophila infection, gene thbd-1, thbd-2 and cd93-2 were significantly up-regulated at one or more timepoints in spleen and kidney, while gene cd248a-1, cd248a-2, cd248b-1, cd248b-2, and cd93-1 were significantly down-regulated. Taken together, all these results suggested that endosialin family genes were involved in host immune response to A. hydrophila infection in common carp, and provided fundamental genomic resources for better understanding the critical roles of endosialin family on the primary innate immune processes in teleost.

Recombinant human soluble thrombomodulin for acute exacerbation of idiopathic pulmonary fibrosis: a nationwide observational study

BACKGROUND

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is the leading cause of death among patients with IPF. However, there is no established treatment for this condition. Hence, we aimed to investigate the effectiveness and safety of recombinant human soluble thrombomodulin (rTM) for the treatment of AE-IPF.

METHODS

Data were retrospectively collected from the Japanese Diagnosis Procedure Combination database from 1 January 2014 to 31 March 2018. We identified adult patients with IPF who received high-dose methylprednisolone (mPSL) therapy and mechanical ventilation upon admission. Eligible patients (n = 2814) were divided into those receiving high-dose mPSL alone (mPSL alone group, n = 2602) and rTM combined with high-dose mPSL (rTM group, n = 212). A stabilised inverse probability of treatment weighting (IPTW) using propensity scores was performed to compare outcomes between the two groups. The primary outcome was in-hospital mortality, and the secondary outcomes were 14- and 28-day mortality, bleeding events and length of hospital stay.

RESULTS

The in-hospital mortality rates of the mPSL alone and rTM groups were 75.9% and 76.9%, respectively. The results did not significantly differ between the two groups after performing a stabilised IPTW. The odds ratio of the rTM group compared to the mPSL alone group was 1.15 (95% confidence interval: 0.71-1.84; p = 0.57). Moreover, the secondary outcomes did not differ significantly between the two groups.

CONCLUSIONS

In patients with AE-IPF who developed severe respiratory failure, rTM in addition to high-dose mPSL was not associated with a better outcome.

New Insights into the Role of the Complement System in Human Viral Diseases

The complement system (CS) is part of the human immune system, consisting of more than 30 proteins that play a vital role in the protection against various pathogens and diseases, including viral diseases. Activated via three pathways, the classical pathway (CP), the lectin pathway (LP), and the alternative pathway (AP), the complement system leads to the formation of a membrane attack complex (MAC) that disrupts the membrane of target cells, leading to cell lysis and death. Due to the increasing number of reports on its role in viral diseases, which may have implications for research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), this review aims to highlight significant progress in understanding and defining the role of the complement system in four groups of diseases of viral etiology: (1) respiratory diseases; (2) acute liver failure (ALF); (3) disseminated intravascular coagulation (DIC); and (4) vector-borne diseases (VBDs). Some of these diseases already present a serious global health problem, while others are a matter of concern and require the collaboration of relevant national services and scientists with the World Health Organization (WHO) to avoid their spread.

Associations between the von Willebrand Factor-ADAMTS13 Axis, Complement Activation, and COVID-19 Severity and Mortality

Background  Endothelial and complement activation were both associated with immunothrombosis, a key determinant of COVID-19 severity, but their interrelation has not yet been investigated.

Objectives  We aimed to determine von Willebrand factor (VWF) antigen (VWF:Ag) concentration, VWF collagen binding activity (VWF:CBA), a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity (ADAMTS13:Ac), and their ratios in hospitalized COVID-19 patients, and to investigate how these parameters and their constellation with complement activation relate to disease severity and in-hospital mortality in COVID-19.

Methods  Samples of 102 hospitalized patients with polymerase chain reaction-confirmed severe acute respiratory syndrome coronavirus 2 positivity were included in our observational cohort study. Patients were stratified according to the peak severity of COVID-19 disease in agreement with the World Health Organization ordinal scale. Twenty-six convalescent plasma donors with previous COVID-19 disease formed the control group. VWF:Ag concentration and VWF:CBA were determined by enzyme-linked immunosorbent assay (ELISA); ADAMTS13:Ac was determined by fluorescence resonance energy transfer. Complement C3 and C3a were measured by turbidimetry and ELISA, respectively. Clinical covariates and markers of inflammation were extracted from hospital records.

Results  VWF:Ag and VWF:CBA were elevated in all groups of hospitalized COVID-19 patients and increased in parallel with disease severity. ADAMTS13:Ac was decreased in patients with severe COVID-19, with the lowest values in nonsurvivors. High (> 300%) VWF:Ag concentrations or decreased (< 67%) ADAMTS13:Ac were associated with higher risk of severe COVID-19 disease or in-hospital mortality. The concomitant presence of decreased ADAMTS13:Ac and increased C3a/C3 ratio—indicating complement overactivation and consumption—was a strong independent predictor of in-hospital mortality.

Conclusion  Our results suggest that an interaction between the VWF-ADAMTS13 axis and complement overactivation and consumption plays an important role in the pathogenesis of COVID-19.

Endothelial thrombomodulin downregulation caused by hypoxia contributes to severe infiltration and coagulopathy in COVID-19 patient lungs

BACKGROUND

Thromboembolism is a life-threatening manifestation of coronavirus disease 2019 (COVID-19). We investigated a dysfunctional phenotype of vascular endothelial cells in the lungs during COVID-19.

METHODS

We obtained the lung specimens from the patients who died of COVID-19. The phenotype of endothelial cells and immune cells was examined by flow cytometry and immunohistochemistry (IHC) analysis. We tested the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the endothelium using IHC and electron microscopy.

FINDINGS

The autopsy lungs of COVID-19 patients exhibited severe coagulation abnormalities, immune cell infiltration, and platelet activation. Pulmonary endothelial cells of COVID-19 patients showed increased expression of procoagulant von Willebrand factor (VWF) and decreased expression of anticoagulants thrombomodulin and endothelial protein C receptor (EPCR). In the autopsy lungs of COVID-19 patients, the number of macrophages, monocytes, and T cells was increased, showing an activated phenotype. Despite increased immune cells, adhesion molecules such as ICAM-1, VCAM-1, E-selectin, and P-selectin were downregulated in pulmonary endothelial cells of COVID-19 patients. Notably, decreased thrombomodulin expression in endothelial cells was associated with increased immune cell infiltration in the COVID-19 patient lungs. There were no SARS-CoV-2 particles detected in the lung endothelium of COVID-19 patients despite their dysfunctional phenotype. Meanwhile, the autopsy lungs of COVID-19 patients showed SARS-CoV-2 virions in damaged alveolar epithelium and evidence of hypoxic injury.

INTERPRETATION

Pulmonary endothelial cells become dysfunctional during COVID-19, showing a loss of thrombomodulin expression related to severe thrombosis and infiltration, and endothelial cell dysfunction might be caused by a pathologic condition in COVID-19 patient lungs rather than a direct infection with SARS-CoV-2.

FUNDING

This work was supported by the Johns Hopkins University, the American Heart Association, and the National Institutes of Health.

Two-stage degradation and novel functional endothelium characteristics of a 3-D printed bioresorbable scaffold

Bioresorbable scaffolds have emerged as a new generation of vascular implants for the treatment of atherosclerosis, and designed to provide a temporary scaffold that is subsequently absorbed by blood vessels over time. Presently, there is insufficient data on the biological and mechanical responses of blood vessels accompanied by bioresorbable scaffolds (BRS) degradation. Therefore, it is necessary to investigate the inflexion point of degradation, the response of blood vessels, and the pathophysiological process of vascular, as results of such studies will be of great value for the design of next generation of BRS. In this study, abdominal aortas of SD rats were received 3-D printed poly-l-actide vascular scaffolds (PLS) for various durations up to 12 months. The response of PLS implanted aorta went through two distinct processes: (1) the neointima with desirable barrier function was obtained in 1 month, accompanied with slow degradation, inflammation, and intimal hyperplasia; (2) significant degradation occurred from 6 months, accompanied with decreasing inflammation and intimal hyperplasia, while the extracellular matrix recovered to normal vessels which indicate the positive remodeling. These in vivo results indicate that 6 months is a key turning point. This “two-stage degradation and vascular characteristics” is proposed to elucidate the long-term effects of PLS on vascular repair and demonstrated the potential of PLS in promoting endothelium function and positive remodeling, which highlights the benefits of PLS and shed some light in the future researches, such as drug combination coatings design.

•

Proposed two-stage degradation of a PLLA BRS to reveal distinct neointimal recovery and vascular responsive processes.

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Revealed novel benefits of BRS, including fine endothelium function, anti-thrombosis, and anti-inflammatory.

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Drug combination coatings should be designed concerning special degradation of BRS and the key turning point, 6 months.

Recombinant thrombomodulin domain 1 rescues pathological angiogenesis by inhibition of HIF-1α-VEGF pathway

Pathological angiogenesis (PA) contributes to various ocular diseases, including age-related macular degeneration, diabetic retinopathy, and retinopathy of prematurity, which are major causes of blindness over the world. Current treatments focus on anti-vascular endothelial growth factor (VEGF) therapy, but persistent avascular retina, recurrent intravitreal neovascularization, and general adverse effects are reported. We have previously found that recombinant thrombomodulin domain 1 (rTMD1) can suppress vascular inflammation. However, the function of rTMD1 in VEGF-induced PA remains unknown. In this study, we found that rTMD1 inhibited VEGF-induced angiogenesis in vitro. In an oxygen induced retinopathy (OIR) animal model, rTMD1 treatment significantly decreased retinal neovascularization but spared normal physiological vessel growth. Furthermore, loss of TMD1 significantly promoted PA in OIR. Meanwhile, hypoxia-inducible factor-1α, the transcription factor that upregulates VEGF, was suppressed after rTMD1 treatment. The levels of interleukin-6, and intercellular adhesion molecule-1 were also significantly suppressed. In conclusion, our results indicate that rTMD1 not only has dual effects to suppress PA and inflammation in OIR, but also can be a potential HIF-1α inhibitor for clinical use. These data bring forth the possibility of rTMD1 as a novel therapeutic agent for PA.

Urinary SARS-CoV-2 RNA Is an Indicator for the Progression and Prognosis of COVID-19

Background: We aimed to analyze clinical characteristics and find potential factors to predict poor prognosis in patients with coronavirus disease 2019 (COVID-19). Methods: We analyzed the clinical characteristics and laboratory tests of COVID-19 patients and detected SARS-CoV-2 RNA in urine sediments collected from 53 COVID-19 patients enrolled in Renmin Hospital of Wuhan University from 31 January 2020 to 18 February 2020 with qRT-PCR analysis. Then, we classified those patients based on clinical conditions (severe or non-severe syndrome) and urinary SARS-CoV-2 RNA (U_RNA⁻ or U_RNA⁺). Results: We found that COVID-19 patients with severe syndrome (severe patients) showed significantly higher positive rate (11 of 23, 47.8%) of urinary SARS-CoV-2 RNA than non-severe patients (4 of 30, 13.3%, p = 0.006). U_RNA⁺ patients or severe U_RNA⁺ subgroup exhibited higher prevalence of inflammation and immune discord, cardiovascular diseases, liver damage and renal dysfunction, and higher risk of death than U_RNA⁻ patients. To understand the potential mechanisms underlying the viral urine shedding, we performed renal histopathological analysis on postmortems of patients with COVID-19 and found severe renal vascular endothelium lesion characterized by an increase of the expression of thrombomodulin and von Willebrand factor, markers to assess the endothelium dysfunction. We proposed a theoretical and mathematic model to depict the potential factors that determine the urine shedding of SARS-CoV-2. Conclusions: This study indicated that urinary SARS-CoV-2 RNA detected in urine specimens can be used to predict the progression and prognosis of COVID-19 severity.

Elevated circulating thrombomodulin levels in systemic lupus erythematosus: a systematic review and meta-analysis

OBJECTIVES

Thrombomodulin (TM) is closely related to the pathogenesis of autoimmune diseases, including systemic lupus erythematosus (SLE). However, current evidence on circulating TM levels in SLE patients is contradictory. We conducted this meta-analysis to more accurately assess circulating TM levels in patients with SLE and lupus nephritis (LN) and to analyze related influencing factors.

METHODS

Systematic search of relevant documents was conducted in PubMed, Embase, and The Cochrane Library databases (up to 28 February 2021). Studies on the comparison of circulating TM between SLE patients and controls were screened and evaluated for inclusion. Random-effects model analysis was applied to calculate the combined standardized mean difference (SMD) with a 95% confidence interval (CI). Heterogeneity was estimated by Q statistics and I2.

RESULTS

A total of 353 articles were identified, 14 provided adequate information for this study finally. The results illustrated that SLE patients had higher TM levels than healthy controls (SMD =0.38, 95% CI: 0.02 to 0.74, p=0.04). Circulating TM levels were increased in patients with active SLE compared to inactive SLE patients (SMD=1.12, 95% CI: 0.03 to 2.20, p=0.04). In addition, circulating TM levels of SLE patients with LN were higher than those without LN (SMD=4.55, 95% CI: 1.97 to 7.12, p=0.001).

CONCLUSIONS

The circulating TM levels in SLE patients are enhanced. In addition, circulating TM levels may be practical in reflecting the disease activity and nephritis involvement of SLE patients.

Human endothelial cells and fibroblasts express and produce the coagulation proteins necessary for thrombin generation

In a previous study, we reported that human endothelial cells (ECs) express and produce their own coagulation factors (F) that can activate cell surface FX without the additions of external proteins or phospholipids. We now describe experiments that detail the expression and production in ECs and fibroblasts of the clotting proteins necessary for formation of active prothrombinase (FV-FX) complexes to produce thrombin on EC and fibroblast surfaces. EC and fibroblast thrombin generation was identified by measuring: thrombin activity; thrombin-antithrombin complexes; and the prothrombin fragment 1.2 (PF1.2), which is produced by the prothrombinase cleavage of prothrombin (FII) to thrombin. In ECs, the prothrombinase complex uses surface-attached FV and γ-carboxyl-glutamate residues of FX and FII to attach to EC surfaces. FV is also on fibroblast surfaces; however, lower fibroblast expression of the gene for γ-glutamyl carboxylase (GGCX) results in production of vitamin K-dependent coagulation proteins (FII and FX) with reduced surface binding. This is evident by the minimal surface binding of PF1.2, following FII activation, of fibroblasts compared to ECs. We conclude that human ECs and fibroblasts both generate thrombin without exogenous addition of coagulation proteins or phospholipids. The two cell types assemble distinct forms of prothrombinase to generate thrombin.

PPARα Modulation-Based Therapy in Central Nervous System Diseases

The burden of neurodegenerative diseases in the central nervous system (CNS) is increasing globally. There are various risk factors for the development and progression of CNS diseases, such as inflammatory responses and metabolic derangements. Thus, curing CNS diseases requires the modulation of damaging signaling pathways through a multitude of mechanisms. Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear hormone receptors (PPARα, PPARβ/δ, and PPARγ), and they work as master sensors and modulators of cellular metabolism. In this regard, PPARs have recently been suggested as promising therapeutic targets for suppressing the development of CNS diseases and their progressions. While the therapeutic role of PPARγ modulation in CNS diseases has been well reviewed, the role of PPARα modulation in these diseases has not been comprehensively summarized. The current review focuses on the therapeutic roles of PPARα modulation in CNS diseases, including those affecting the brain, spinal cord, and eye, with recent advances. Our review will enable more comprehensive therapeutic approaches to modulate PPARα for the prevention of and protection from various CNS diseases.

The Evolving Concept of Neuro-Thromboinflammation for Neurodegenerative Disorders and Neurotrauma: A Rationale for PAR1-Targeting Therapies

Interest in the role of coagulation and fibrinolysis in the nervous system was active in several laboratories dating back before cloning of the functional thrombin receptor in 1991. As one of those, our attention was initially on thrombin and plasminogen activators in synapse formation and elimination in the neuromuscular system, with orientation towards diseases such as amyotrophic lateral sclerosis (ALS) and how clotting and fibrinolytic pathways fit into its pathogenesis. This perspective is on neuro-thromboinflammation, emphasizing this emerging concept from studies and reports over more than three decades. It underscores how it may lead to novel therapeutic approaches to treat the ravages of neurotrauma and neurodegenerative diseases, with a focus on PAR1, ALS, and parmodulins.

Thrombomodulin in patients with mild to moderate bleeding tendency

Introduction

A massive increase of soluble thrombomodulin (sTM) due to variants in the thrombomodulin gene (THBD) has recently been identified as a novel bleeding disorder.

Aim

To investigate sTM levels and underlying genetic variants as a cause for haemostatic impairment and bleeding in a large number of patients with a mild to moderate bleeding disorder (MBD), including patients with bleeding of unknown cause (BUC).

Patients and methods

In 507 MBD patients, sTM levels, thrombin generation and plasma clot formation were measured and compared to 90 age‐ and sex‐matched healthy controls. In patients, genetic analysis of the THBD gene was performed.

Results

No difference in sTM levels between patients and controls was found overall (median ([IQR] 5.0 [3.8‐6.3] vs. 5.1 [3.7‐6.4] ng/ml, p = .762), and according to specific diagnoses of MBD or BUC, and high sTM levels (≥95th percentile of healthy controls) were not overrepresented in patients. Soluble TM levels had no impact on bleeding severity or global tests of haemostasis, including thrombin generation or plasma clot formation. In the THBD gene, no known pathogenic or novel disease‐causing variants affecting sTM plasma levels were identified in our patient cohort.

Conclusion

TM‐associated coagulopathy appears to be rare, as it was not identified in our large cohort of patients with MBD. Soluble TM did not arise as a risk factor for bleeding or altered haemostasis in these patients.

A Review of Neutrophil Extracellular Traps (NETs) in Disease: Potential Anti-NETs Therapeutics

Activated neutrophils release neutrophil extracellular traps (NETs) in response to a variety of stimuli. NETosis is driven by protein-arginine deiminase type 4, with the release of intracellular granule components that function by capturing and destroying microbes, including viral, fungal, bacterial, and protozoal pathogens. The positive effects of pathogen control are countered by pro-inflammatory effects as demonstrated in a variety of diseases. Components of NETS are non-specific, and other than controlling microbes, they cause injury to surrounding tissue by themselves or by increasing the pro-inflammatory response. NETs can play a role in enhancement of the inflammation seen in autoimmune diseases including psoriasis, rheumatoid arthritis, and systemic lupus erythematosis. In addition, autoinflammatory diseases such as gout have been associated with NETosis. Inhibition of NETs may decrease the severity of many diseases improving survival. Herein, we describe NETosis in different diseases focusing on the detrimental effect of NETs and outline possible therapeutics that can be used to mitigate netosis. There is a need for more studies and clinical trials on these and other compounds that could prevent or destroy NETs, thereby decreasing damage to patients.

Coagulation Dysfunction in Acute Respiratory Distress Syndrome and Its Potential Impact in Inflammatory Subphenotypes

The Acute Respiratory Distress Syndrome (ARDS) has caused innumerable deaths worldwide since its initial description over five decades ago. Population-based estimates of ARDS vary from 1 to 86 cases per 100,000, with the highest rates reported in Australia and the United States. This syndrome is characterised by a breakdown of the pulmonary alveolo-epithelial barrier with subsequent severe hypoxaemia and disturbances in pulmonary mechanics. The underlying pathophysiology of this syndrome is a severe inflammatory reaction and associated local and systemic coagulation dysfunction that leads to pulmonary and systemic damage, ultimately causing death in up to 40% of patients. Since inflammation and coagulation are inextricably linked throughout evolution, it is biological folly to assess the two systems in isolation when investigating the underlying molecular mechanisms of coagulation dysfunction in ARDS. Although the body possesses potent endogenous systems to regulate coagulation, these become dysregulated and no longer optimally functional during the acute phase of ARDS, further perpetuating coagulation, inflammation and cell damage. The inflammatory ARDS subphenotypes address inflammatory differences but neglect the equally important coagulation pathway. A holistic understanding of this syndrome and its subphenotypes will improve our understanding of underlying mechanisms that then drive translation into diagnostic testing, treatments, and improve patient outcomes.

Functional and Cognitive Decline Is Associated With Increased Endothelial Cell Inflammation and Platelet Activation: Liquid Biopsy of Microvesicles in Community- Dwelling Octogenarians

Increased life expectancy is usually associated with comorbidities, such as cardio and cerebrovascular disease causing impaired functionality. A common underlying cause of these comorbidities is vascular inflammation and injury. Elevated levels of circulating microvesicles (cMV), as a product of a hemostatic and inflammatory cell activation, could be direct mapping of an imbalanced hemostasis. In this manuscript, we aimed to investigate by liquid biopsy whether successful aging can be discriminated by cMV levels and phenotype. To this purpose, we included 135 community-dwelling octogenarians in a cross-sectional study. Successful aging was defined as good functional (Barthel Index > 90 points, and Lawton index score > 7/4 points for women and men, respectively) and cognitive status (Spanish version of the Mini-Mental State Examination -MEC- > 24 points) and no need for institutionalization. Total, annexin V positive (AV⁺), and AV^– cMV from different cell origins from the vascular compartment were phenotypically characterized and quantified from fasting plasma samples by flow cytometry. Successful aging was associated with lower plasma concentrations of total and AV⁺ CD141⁺/CD41⁺-CD61⁺, and PAC1⁺/AV⁺, CD141⁺/AV⁺, and CD36⁺/AV^– cMV. From these phenotypes, ROC curve analyses revealed that CD141⁺/AV⁺ and CD141⁺/CD41⁺-CD61⁺/AV⁺ endothelial- and platelet-derived cMV discriminate successful and non-successful aging with an AUC (95%CI) of 0.655 (0.551, 0.758), P = 0.005, and 0.638 (0.535, 0.741), P = 0.013, respectively. In conclusion, successful aging is associated with low levels of cMV released by endothelial cells and platelets, indicating lower endothelial cell inflammation and platelet activation. Our results contribute to the understanding of the link between unsuccessful aging, cognitive decline and vascular cell inflammatory disturbances.

Impact of chronic smoking on traumatic brain microvascular injury: An in vitro study

Traumatic brain injury (TBI) is a major reason of cerebrovascular and neurological damage. Premorbid conditions such as tobacco smoking (TS) can worsen post‐TBI injuries by promoting vascular endothelial impairments. Indeed, TS‐induced oxidative stress (OS) and inflammation can hamper the blood‐brain barrier (BBB) endothelium. This study evaluated the subsequence of chronic TS exposure on BBB endothelial cells in an established in vitro model of traumatic cell injury. Experiments were conducted on confluent TS‐exposed mouse brain microvascular endothelial cells (mBMEC‐P5) following scratch injury. The expression of BBB integrity–associated tight junction (TJ) proteins was assessed by immunofluorescence imaging (IF), Western blotting (WB) and quantitative RT‐PCR. We evaluated reactive oxygen species (ROS) generation, the nuclear factor 2–related (Nrf2) with its downstream effectors and several inflammatory markers. Thrombomodulin expression was used to assess the endothelial haemostatic response to injury and TS exposure. Our results show that TS significantly decreased Nrf2, thrombomodulin and TJ expression in the BBB endothelium injury models while increased OS and inflammation compared to parallel TS‐free cultures. These data suggest that chronic TS exposure exacerbates traumatic endothelial injury and abrogates the protective antioxidative cell responses. The downstream effect was a more significant decline of BBB endothelial viability, which could aggravate subsequent neurological impairments.

Stable expression of the human thrombomodulin transgene in pig endothelial cells is associated with a reduction in the inflammatory response

BACKGROUND

Xenotransplantation is associated with an inflammatory response. The proinflammatory cytokine, TNF-α, downregulates the expression of thrombomodulin (TBM), and induces coagulation dysfunction. Although human (h) TBM-transgenic pigs (p) have been developed to reduce coagulation dysfunction, the effect of TNF-α on the expression of hTBM and its functional activity has not been fully investigated. The aims of this study were to investigate (i) whether the expression of hTBM on pig (p) cells is down-regulated during TNF-α stimulation, and (ii) whether cells from hTBM pigs regulate the inflammatory response.

METHODS

TNF-α-producing T, B, and natural killer cells in blood from baboons with pig heart or kidney xenografts were investigated by flow cytometry. TNF-α staining in the grafts was detected by immunohistochemistry. Aortic endothelial cells (AECs) from GTKO/CD46 and GTKO/CD46/hTBM pigs were stimulated by hTNF-α, and the expression of the inflammatory/coagulation regulatory protein, TBM, was investigated.

RESULTS

After pig organ xenotransplantation, there was a trend to increases in TNF-α-producing T and natural killer cells in the blood of baboons. In vitro observations demonstrated that after hTNF-α stimulation, there was a significant reduction in the expression of endogenous pTBM on pAECs, and a significant increase in the expression of inflammatory molecules. Blocking of NF-κB signaling significantly up-regulated pTBM expression, and suppressed the inflammatory response induced by hTNF-α in pAECs. Whereas the expression of pTBM mRNA was significantly reduced by hTNF-α stimulation, hTBM expression on the GTKO/CD46/hTBM pAECs was not affected. Furthermore, after hTNF-α stimulation, there was significant suppression of expression of inflammatory molecules on GTKO/CD46/hTBM pAECs compared to GTKO/CD46 pAECs.

CONCLUSIONS

The stable expression of hTBM in pig cells may locally regulate the inflammatory response. This will help suppress the inflammatory response and prevent coagulation dysregulation after xenotransplantation.

Elevated plasma levels of syndecan-1 and soluble thrombomodulin predict adverse outcomes in thrombotic thrombocytopenic purpura

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal blood disorder resulting from acquired deficiency of plasma ADAMTS13 activity. Despite recent advances in early diagnosis and novel therapeutics, the mortality rate of acute iTTP remains as high as 10% to 20%. Moreover, a reliable clinical and laboratory parameter that predicts disease severity and outcomes is lacking. We show in the present study that plasma levels of syndecan-1 (Sdc-1) and soluble thrombomodulin (sTM) on admission were dramatically increased in patients with acute iTTP and remained substantially elevated in a subset of patients compared with healthy controls. The elevated admission plasma levels of Sdc-1 and sTM were associated with abnormal Glasgow coma scale scores, low estimated glomerular filtration rates, the need for intensive care, and in-hospital mortality rates. Moreover, a further simultaneous increase in plasma Sdc-1 and sTM levels at the time of clinical response/remission (eg, when normalization of platelet counts and substantial reduction of serum lactate dehydrogenase activity were achieved) was highly predictive of iTTP recurrence. These results demonstrate that endothelial injury, resulting from disseminated microvascular thromboses, is severe and persistent in patients with acute iTTP. Plasma levels of Sdc-1 and sTM on admission and in remission are predictive of in-hospital mortality and recurrence of acute iTTP, respectively. Thus, an incorporation of such novel plasma biomarkers into the risk assessment in acute iTTP may help implement a more vigorous and intensive therapeutic strategy for these patients.

Disruption of the blood-brain barrier in 22q11.2 deletion syndrome

Neuroimmune dysregulation is implicated in neuropsychiatric disorders including schizophrenia. As the blood-brain barrier is the immunological interface between the brain and the periphery, we investigated whether this vascular phenotype is intrinsically compromised in the most common genetic risk factor for schizophrenia, the 22q11.2 deletion syndrome (22qDS). Blood-brain barrier like endothelium differentiated from human 22qDS+schizophrenia-induced pluripotent stem cells exhibited impaired barrier integrity, a phenotype substantiated in a mouse model of 22qDS. The proinflammatory intercellular adhesion molecule-1 was upregulated in 22qDS+schizophrenia-induced blood-brain barrier and in 22qDS mice, indicating compromise of the blood-brain barrier immune privilege. This immune imbalance resulted in increased migration/activation of leucocytes crossing the 22qDS+schizophrenia blood-brain barrier. We also found heightened astrocyte activation in murine 22qDS, suggesting that the blood-brain barrier promotes astrocyte-mediated neuroinflammation. Finally, we substantiated these findings in post-mortem 22qDS brain tissue. Overall, the barrier-promoting and immune privilege properties of the 22qDS blood-brain barrier are compromised, and this might increase the risk for neuropsychiatric disease.