Protective, repairing and fibrinolytic effects of rivaroxaban on vascular endothelium

Comparative Cardioprotective Effectiveness: NOACs vs. Nattokinase-Bridging Basic Research to Clinical Findings

The use of non-vitamin K antagonist oral anticoagulants (NOACs) has brought a significant progress in the management of cardiovascular diseases, considered clinically superior to vitamin K antagonists (VKAs) particularly in the prevention and treatment of thromboembolic events. In addition, numerous advantages such as fixed dosing, lack of laboratory monitoring, and fewer food and drug-to-drug interactions make the use of NOACs superior to VKAs. While NOACs are synthetic drugs prescribed for specific conditions, nattokinase (NK) is a natural enzyme derived from food that has potential health benefits. Various experimental and clinical studies reported the positive effects of NK on the circulatory system, including the thinning of blood and the dissolution of blood clots. This enzyme showed not only fibrinolytic activity due to its ability to degrade fibrin, but also an affinity as a substrate for plasmin. Recent studies have shown that NK has additional cardioprotective effects, such as antihypertensive and anti-atherosclerotic effects. In this narrative review, we presented the cardioprotective properties of two different approaches that go beyond anticoagulation: NOACs and NK. By combining evidence from basic research with clinical findings, we aim to elucidate the comparative cardioprotective efficacy of these interventions and highlight their respective roles in modern cardiovascular care.

Pleiotropic Effects of Direct Oral Anticoagulants in Chronic Heart Failure and Atrial Fibrillation: Machine Learning Analysis

Oral anticoagulant therapy (OAT) for managing atrial fibrillation (AF) encompasses vitamin K antagonists (VKAs, such as warfarin), which was the mainstay of anticoagulation therapy before 2010, and direct-acting oral anticoagulants (DOACs, namely dabigatran etexilate, rivaroxaban, apixaban, edoxaban), approved for the prevention of AF stroke over the last thirteen years. Due to the lower risk of major bleeding associated with DOACs, anticoagulant switching is a common practice in AF patients. Nevertheless, there are issues related to OAT switching that still need to be fully understood, especially for patients in whom AF and heart failure (HF) coexist. Herein, the effective impact of the therapeutic switching from warfarin to DOACs in HF patients with AF, in terms of cardiac remodeling, clinical status, endothelial function and inflammatory biomarkers, was assessed by a machine learning (ML) analysis of a clinical database, which ultimately shed light on the real positive and pleiotropic effects mediated by DOACs in addition to their anticoagulant activity.

Prescriber decision-making on antithrombotic therapy after endovascular intervention for peripheral artery disease: a protocol for a discrete choice experiment

INTRODUCTION

Peripheral artery disease (PAD) is a major risk factor for cardiovascular morbidity and mortality, despite surgical and endovascular treatments. Emerging evidence supports the use of immediate antithrombotic medications after endovascular intervention for PAD, however, there is a lack of consensus regarding choice and duration of antithrombotic therapy. Prescriber decision-making is a complex process, with prior studies demonstrating patient factors can influence variability in antithrombotic therapy for PAD. However, it remains unclear the relative contribution of these factors. This paper describes a planned study that aims to (1) determine the influence of patient factors on clinician preference for antithrombotic therapy following endovascular intervention and (2) compare differences in prescribing preferences between consultant vascular surgeons and trainees.

METHODS AND ANALYSIS

This cross-sectional survey will evaluate antithrombotic prescribing choices using a discrete choice experiment (DCE) that has been developed and piloted for this study. A list of attributes and levels was generated using a mixed-methods approach. This included an extensive literature review and semistructured interviews with prescribing clinicians. Following final selection of included attributes, specialised software was used to construct a D-efficient design for the DCE questionnaire. The electronic questionnaire will be administered to vascular trainees and consultant surgeons across Australia. These data will be analysed using multinomial logistic regression, treating the decision to prescribe antithrombotic therapy as a function of both the attributes of the two alternatives, as well as characteristics of the respondent. Latent class analysis will be used to explore heterogeneity of responses.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the University of Sydney Human Ethics committee (2023/474). The results of this study will be published in peer-reviewed journals and presented at national vascular surgical conferences. These results will be used to improve understanding how clinicians make prescribing decisions and to inform future strategy to enhance guideline-directed prescribing.

Distinct pleiotropic effects of direct oral anticoagulants on cultured endothelial cells: a comprehensive review

Direct Oral Anticoagulants (DOACs) have simplified the treatment of thromboembolic disease. In addition to their established anticoagulant effects, there are indications from clinical and preclinical studies that DOACs exhibit also non-anticoagulant actions, such as anti-inflammatory and anti-oxidant actions, advocating overall cardiovascular protection. In the present study, we provide a comprehensive overview of the existing knowledge on the pleiotropic effects of DOACs on endothelial cells (ECs) in vitro and their underlying mechanisms, while also identifying potential differences among DOACs. DOACs exhibit pleiotropic actions on ECs, such as anti-inflammatory, anti-atherosclerotic, and anti-fibrotic effects, as well as preservation of endothelial integrity. These effects appear to be mediated through inhibition of the proteinase-activated receptor signaling pathway. Furthermore, we discuss the potential differences among the four drugs in this class. Further research is needed to fully understand the pleiotropic effects of DOACs on ECs, their underlying mechanisms, as well as the heterogeneity between various DOACs. Such studies can pave the way for identifying biomarkers that can help personalize pharmacotherapy with this valuable class of drugs.

Predictive value of von Willebrand factor for venous thrombosis in patients with chronic heart failure complicated with atrial fibrillation after anticoagulant therapy

BACKGROUND

We investigated the value of von Willebrand factor (vWF) in predicting venous thrombosis in patients with chronic heart failure complicated with atrial fibrillation after anticoagulation therapy.

METHODS

Totally, 126 patients with chronic heart failure complicated with atrial fibrillation who were treated with anticoagulant therapy and 60 healthy individuals were enrolled. One year after anticoagulant therapy, venous thrombosis occurred in 19 patients. Clinical data of patients were collected. The plasma vWF activity was detected and compared. The logistic regression analysis was used to analyze the influencing factors of vWF. ROC curve was used to evaluate the predictive value of plasma vWF.

RESULTS

Plasma vWF activity was significantly higher in patients with heart failure and atrial fibrillation than control subjects (P < 0.01). The vWF activity in patients with venous thrombosis was significantly higher than that in patients without venous thrombosis (P < 0.01). ROC curve analysis showed that the cut-off value of vWF activity for venous thrombosis within one year after anticoagulant therapy was 267.5%, and the AUC was 0.742 (95% CI: 0.764-0.921, P < 0.05). The sensitivity was 80.0%, and the specificity was 63.6%. Factors of diabetes, myocardial ischemia, old myocardial infarction, and lower extremity atherosclerosis, but not sex, age, coronary heart disease, hypertension, and cardiac function, had significant effect on vWF activity (P < 0.05). Logistic regression analysis showed that vWF activity was significantly related with atherosclerosis of lower limbs and old myocardial infarction, but not significantly related with diabetes and myocardial ischemia. The risk of venous thrombosis in patients with vWF activity greater than 267.5% was 10.667 times higher than that in patients with vWF activity less than 267.5% (P < 0.05).

CONCLUSION

The vWF activity greater than 267.5% has clinical predictive value for the risk of lower extremity venous thrombosis in patients with chronic heart failure complicated with atrial fibrillation within 1 year of anticoagulant therapy.

Vascular protection with rivaroxaban in the comprehensive management of atrial fibrillation

INTRODUCTION

In addition to an increased risk of thromboembolic complications, patients with atrial fibrillation (AF) are at risk for vascular events. Consequently, complete vascular protection is warranted in these patients.

AREAS COVERED

A narrative search was conducted on PubMed (MEDLINE), using the MeSH terms [Rivaroxaban] + [Atrial fibrillation] + [Cardiovascular] + [Vascular] + [Treatment]. Original data from clinical trials, prospective and retrospective studies, useful reviews and experimental studies, were selected.

EXPERT OPINION

The ROCKET-AF trial showed that rivaroxaban is effective in reducing the risk of stroke, with a lower risk of fatal and intracranial bleeding compared to warfarin. Remarkably, experimental data have provided a number of pathogenic mechanisms through which rivaroxaban could provide beneficial vascular properties beyond its antithrombotic activity. Moreover, in the AF population, additional to its ability to reduce the risk of thromboembolic complications, rivaroxaban is associated with a lower risk of myocardial infarction, major adverse cardiac and limb events, and vascular mortality in patients with diabetes, also attenuating renal impairment during follow-up. These findings suggest that rivaroxaban may provide a comprehensive vascular protection in patients with AF.

Should atrial fibrillation be considered a vascular disease? The need for a comprehensive vascular approach

INTRODUCTION

Atrial fibrillation (AF) cannot be considered an isolated disease. Patients with AF should be managed using a comprehensive approach that is not limited to stroke prevention.

AREAS COVERED

In this manuscript, the potential role of AF as a vascular disease that is managed as part of a holistic approach was reviewed.

EXPERT OPINION

The residual risk of stroke in patients with AF reaches 1-2% annually, despite appropriate anticoagulation therapy. Additionally, patients with AF may develop cognitive impairment through stroke-independent pathways. Furthermore, patients with AF may have a higher risk of developing atherosclerotic vascular disease in various vascular beds and chronic kidney disease; conversely, patients with atherosclerotic disease may have an increased risk of developing AF. AF should be considered a truly systemic vascular disease, since it brings together several hemodynamic and systemic changes, including inflammation, oxidative stress, activation of the renin-angiotensin-aldosterone and sympathetic systems, as well as a prothrombotic state and endothelial dysfunction. In this regard, patients with AF should be treated based on a holistic approach that is not limited to oral anticoagulation but includes complete vascular protection.

Delivery of rivaroxaban and chitosan rapamycin microparticle with dual antithrombosis and antiproliferation functions inhibits venous neointimal hyperplasia

Neointimal hyperplasia is a complex process after vascular interventions, acute platelet deposition and smooth muscle cell proliferation both contributed to this process. There are still no perfect solutions to solve this problem. Rivaroxaban is a novel anticoagulant that has been widely used in clinic, it has a good pharmacological effects both in vivo and in vitro. Chitosan microparticle rapamycin (MP-rapa) was fabricated, interspaces of polyglycolic acid (PGA) scaffold were used as a reservoir of MP-rapa, and the scaffold was coated with hyaluronic acid rivaroxaban (MP-rapa-riva). Scanning electronic microscopy (SEM) photographs were taken and water contact angles were measured, rat inferior vena cava (IVC) patch venoplasty model was used; patches were harvested at day 14 and examined by immunohistochemistry and immunofluorescence. SEM photographs showed the microparticles rapamycin were inside the interspace of the scaffold, hyaluronic acid rivaroxaban was also successfully coated onto the surface of the scaffold. There was a thinner neointima, fewer proliferating cell nuclear antigen (PCNA) positive cells, fewer macrophages in the MP-rapa and MP-rapa-riva grafts compared to the control PGA graft. The result showed that this scaffold with dual anticoagulation and antiproliferation functions can effectively inhibit venous neointimal hyperplasia, although this is an animal experiment, it showed promising potential clinical application in the future.

Beneficial Effect of Edoxaban on Preventing Atrial Fibrillation and Coagulation by Reducing Inflammation via HBG1/HBD Biomarkers

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia. The effectiveness and mechanism of edoxaban in preventing stroke after atrial fibrillation remain unclear. Methods: The expressions of HBG1 and HBD in red blood cells were tested in AF. Sixty C57B/6J mice were randomly divided into the following groups: the control (CON) group, atrial fibrillation (AF) group, AF + edoxaban group, and AF + rivaroxaban group. H&E staining assay and reticular fiber staining were performed. Myocardial fibrosis was evaluated by the Masson staining assay, Sirius red staining assay, and immunohistochemical assay for the expressions of α-SMA and COL1A1. ELISA and RT-PCR assay were performed for the detection of inflammatory parameters (TNF-α, IL-1β, IL-6, and IL-10). Blood lipids were detected by using the Beckman automatic biochemical analyzer. Furthermore, four items of coagulation were detected, and molecular docking among HBG1, HBD, and MASP1 (Xa) was performed by PyMOL 2.1 software. The BP neural network model, cubic spline interpolation, and support vector machine model were constructed to predict prothrombin time based on HBG1 and HBD expressions. COIP assay was performed to construct the interaction between HBG1 and HBD. The functional enrichment analysis was performed by DAVID and Metascape tools. Results: The expressions of HBG1 and HBD in red blood cells of the patients with atrial fibrillation were decreased. The results showed a lower level of hemoglobin in red blood cells with HBG1-siRNA and HBG1-siRNA. Compared with the AF group, the collagen fiber percentage in the AF + edoxaban group was decreased (p < 0.05). After using edoxaban, the expressions of TNF-α, IL-1β, IL-6, and IL-10 were significantly decreased (p < 0.05). The LDL-C, TC, and TG levels were downregulated in the AF + edoxaban group. The PT and APTT levels in the AF + edoxaban group were more increasing than in the AF mice (p < 0.05). Compared with the AF group, the expressions of HBG1 and HBD were downregulated in the AF + edoxaban group (p < 0.05). HBG1 protein matched well with HBD and MASP1(Xa) protein surfaces. There exists a significant interaction between HBG1, HBD, and PT via the BP neural network and support vector machine. Enrichment analysis showed that HBG1 and HBD were mainly enriched in blood coagulation. Conclusion: Edoxaban could prevent atrial fibrillation and coagulation by reducing inflammation, lipids, and fibrosis via HBG1/HBD biomarkers effectively, and the effect was superior to that of rivaroxaban.

CM-352 EFFICACY IN A MOUSE MODEL OF ANTICOAGULANT-ASSOCIATED INTRACRANIAL HAEMORRHAGE

BACKGROUND

Intracranial haemorrhage (ICH) is one of the major devastating complications of anticoagulation. Matrix metalloproteinases (MMPs) inhibition has been proposed as a novel pharmacological approach for ICH treatment.

OBJECTIVES

We evaluated the effects of CM-352 (MMPs-fibrinolysis inhibitor) in an experimental ICH model associated with oral anticoagulants as compared with clinically used prothrombin concentrate complex (PCC).

METHODS

ICH was induced by collagenase injection into the striatum of WT (C57BL/6J) anticoagulated mice (warfarin or rivaroxaban) and Mmp10 -/- mice. Hematoma volume and neurological deficits were measured 24h later by diaminobenzidine staining and different behavioural test. Circulating plasminogen activator inhibitor-1 (PAI-1) activity and interleukin-6 (IL-6) were measured in plasma samples and local inflammation was assessed by neutrophil infiltration. Finally, fibrinolytic effects of MMP-10 and rivaroxaban were evaluated by thromboelastometry and thrombin-activatable fibrinolysis inhibitor (TAFI) activation assays.

RESULTS

Only PCC reduced haemorrhage volume and improved functional outcome in warfarin-ICH, but both, PCC and CM-352 treatments, diminished haemorrhage volume (46%, p<0.01 and 64%, p<0.001, respectively) and ameliorated functional outcome in rivaroxaban-ICH. We further demonstrated that CM-352, but not PCC decreased neutrophil infiltration in the haemorrhage area at 24h. The effect of CM-352 could be related to MMP-10 inhibition since Mmp10-/- mice showed lower haemorrhage volume, better neurological score, reduced IL-6 levels and neutrophil infiltration, and increased PAI-1 after experimental ICH. Finally, we found that CM-352 reduced MMP-10 and rivaroxaban-related fibrinolytic effects in thromboelastometry and TAFI activation.

CONCLUSIONS

CM-352 treatment, by diminishing MMPs and rivaroxaban-associated fibrinolytic effects, might be a novel antihaemorrhagic strategy for rivaroxaban-associated ICH.

Rivaroxaban compared with low-dose aspirin in individuals with type 2 diabetes and high cardiovascular risk: a randomised trial to assess effects on endothelial function, platelet activation and vascular biomarkers

AIMS/HYPOTHESIS

Individuals with type 2 diabetes mellitus and subclinical inflammation have stimulated coagulation, activated platelets and endothelial dysfunction. Recent studies with the direct factor Xa inhibitor rivaroxaban in combination with low-dose aspirin demonstrated a significant reduction of major cardiovascular events, especially in individuals with type 2 diabetes and proven cardiovascular disease. Therefore, we asked the question of whether treatment with rivaroxaban could influence endothelial function, arterial stiffness and platelet activation.

METHODS

We conducted a multi-centre, prospective, randomised, open-label trial in 179 participants with type 2 diabetes (duration 2-20 years), subclinical inflammation (high-sensitivity C-reactive protein 2-10 mg/l) and at least two traits of the metabolic syndrome to compare the effects of the direct factor Xa inhibitor rivaroxaban (5 mg twice daily) vs aspirin (100 mg every day) on endothelial function (assessed by forearm occlusion plethysmography), skin blood flow (assessed by laser-Doppler fluxmetry), arterial stiffness (assessed by pulse wave velocity) and serum biomarkers of endothelial function and inflammation. Furthermore, we investigated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) in platelets, the concentration of platelet-derived microparticles (PMPs) and the effects of isolated PMPs on HUVEC proliferation in vitro.

RESULTS

Rivaroxaban treatment for 20 weeks (n = 89) resulted in a significant improvement of post-ischaemic forearm blood flow (3.6 ± 4.7 vs 1.0 ± 5.2 ml/100 ml, p = 0.004), a numerically increased skin blood flow and reduced soluble P-Selectin plasma level vs aspirin. We did not find significant differences of arterial stiffness or further biomarkers. Neither rivaroxaban nor aspirin influenced VASP phosphorylation of platelets. The number of PMPs increased significantly with both rivaroxaban (365.2 ± 372.1 vs 237.4 ± 157.1 μl^-1, p = 0.005) and aspirin (266.0 ± 212.7 vs 201.7 ± 162.7 μl^-1, p = 0.021). PMPs of rivaroxaban-treated participants stimulated HUVEC proliferation in vitro compared with aspirin. Rivaroxaban was associated with a higher number of bleeding events.

CONCLUSIONS/INTERPRETATION

Our findings indicate that the direct factor Xa inhibitor rivaroxaban improved endothelial function in participants with type 2 diabetes and subclinical inflammation but also increased the risk of bleeding.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02164578.

FUNDING

The study was supported by a research grant from Bayer Vital AG, Germany.

Rivaroxaban protects from the oxysterol-induced damage and inflammatory activation of the vascular endothelium

BACKGROUND

Rivaroxaban is one of the direct factor Xa inhibitors. Its function in the inactivated coagulation cascade is unclear. The aim of the study was to assess the effect of rivaroxaban on the endothelial integrity and inflammatory properties of endothelial cells stimulated by 25-hydroxycholesterol (25-OHC).

METHODS

HUVECs were stimulated with 25-OHC, rivaroxaban and 25-OHC+ rivaroxaban. HUVEC integrity and permeability were measured using the xCELLigence system and paracellular flux assay. The mRNA expression of tissue factor, ICAM-1, VEGF, IL-33, MCP-1, TNF-α was analyzed in the real-time PCR. Apoptosis and viability were measured by flow cytometry. The VEGF protein concentration was assessed by ELISA. The confocal microscope was used to evaluate the expression of VE-cadherin in endothelial cells.

RESULTS

25-OHC decreased endothelial cell integrity and increased the mRNA expression of IL-33, tissue factor, ICAM-1, MCP-1, VEGF, TNF-α as compared to unstimulated controls. Following the stimulation with rivaroxaban, HUVEC restored integrity disrupted by 25-OHC (p < .01). In HUVECs pre-stimulated with oxysterol, rivaroxaban decreased mRNA expression of IL-33, TNF-α, chemokines MCP-1, ICAM-1, VEGF and tissue factor (p < .01). Rivaroxaban 100 mg/ml+25-OHC increased the VE-cadherin expression in endothelium as compared to 25-OHC (p < .05).

CONCLUSION

Our finding suggests that rivaroxaban may restore the endothelial barrier and inhibit the inflammatory activation caused by oxysterol in vitro.

Peri-interventional Triple Therapy With Dabigatran Improves Vasomotion and Promotes Endothelialization in Porcine Coronary Stenting Model

Objective: We evaluated the short and long-term effect of peri-interventional dabigatran therapy on vasomotion, endothelialization, and neointimal formation in a porcine coronary artery stenting model. Background: Stenting of coronary arteries induces local inflammation, impairs vasomotion and delays endothelialization. Methods: Twenty-eight animals underwent percutaneous coronary intervention (PCI) with drug eluting stents. Sixteen pigs started dabigatran therapy 4 days prior to PCI and continued for 4 days post-stenting, while 12 animals served as controls. Post-stenting dual antiplatelet therapy (75 mg clopidogrel and 100 mg aspirin) was continued in both groups until termination. Immediately post-stenting and at day 3 optical coherence tomography (OCT) was performed in all animals, followed by euthanasia of 8 dabigatran and 4 control animals. The remaining pigs (8 of each group) were followed up for 1 month, with control angiography and OCT. Tissue burden (degree of peri-strut structure-thrombus and/or fibrin) was evaluated. After euthanasia coronary arteries were harvested for in-vitro myometry and histology. Results: Thrombin generation was lower (p < 0.001) and tissue burden (0.83 ± 0.98 vs. 3.0 ± 2.45; p = 0.031) was significantly decreased in dabigatran treated animals. After 3 days post-PCI endothelium-dependent vasodilation was significantly improved (77 ± 40% vs. 41 ± 31%, p = 0.02) in dabigatran animals. Neither quantitative angiography nor histomorphometry showed differences between the groups. Endothelialization was faster in the dabigatran group as compared with controls (p = 0.045). Conclusion: Short-term peri-interventional triple therapy with dabigatran, aspirin, and clopidogrel led to an enhanced endothelium dependent vasodilation and faster endothelialization. However, neointimal formation 1-month after stent implantation was comparable between groups.

Direct Rivaroxaban-Induced Factor XA Inhibition Proves to be Cardioprotective in Rats

BACKGROUND

Acute myocardial infarction is a leading cause of death worldwide. Though highly beneficial, reperfusion of myocardium is associated with reperfusion injury. While indirect inhibition of Factor Xa has been shown to attenuate myocardial ischemia-reperfusion (I/R) injury, the underlying mechanism remains unclear. Our study sought to evaluate the effect of rivaroxaban (RIV), a direct inhibitor of Factor Xa, on myocardial I/R injury and determine its cellular targets.

EXPERIMENTAL APPROACH

We used a rat model of 40-min coronary ligation followed by reperfusion. RIV (3 mg/kg) was given per os 1 h before reperfusion. Infarct size and myocardial proteic expression of survival pathways were assessed at 120 and 30 min of reperfusion, respectively. Plasmatic levels of P-selectin and von Willebrand factor were measured at 60 min of reperfusion. Cellular RIV effects were assessed using hypoxia-reoxygenation (H/R) models on human umbilical vein endothelial cells and on rat cardiomyoblasts (H9c2 cell line).

KEY RESULTS

RIV decreased infarct size by 21% (42.9% vs. 54.2% in RIV-treated rats and controls respectively, P < 0.05) at blood concentrations similar to human therapeutic (387.7 ± 152.3 ng/mL) levels. RIV had no effect on H/R-induced modulation of endothelial phenotype, nor did it alter myocardial activation of reperfusion injury salvage kinase and survivor activating factor enhancement pathways at 30 min after reperfusion. However, RIV exerted a cytoprotective effect on H9c2 cells submitted to H/R.

CONCLUSIONS

RIV decreased myocardial I/R injury in rats at concentrations similar to human therapeutic ones. This protection was not associated with endothelial phenotype modulation but rather with potential direct cytoprotection on cardiomyocytes.

Increased Levels of Platelets and Endothelial-Derived Microparticles in Patients With Non-Valvular Atrial Fibrillation During Rivaroxaban Therapy

It is known that atrial fibrillation (AF) is associated with the procoagulant state. Several studies have reported an increase of circulating microparticles in AF, which may be linked to a hypercoagulable state, atrial thrombosis and thromboembolism. We evaluated in our study alterations in both platelet (PMP, CD42b) and endothelial-derived (EMP, CD144) microparticle levels on anticoagulant therapy with rivaroxaban in nonvalvular AF. After administration of rivaroxaban, PMP levels were increased (median, [IQR] 35.7 [28.8-47.3] vs. 48.4 [30.9-82.8] cells/µL; P = 0.012), along with an increase in EMP levels (14.6 [10.0-18.6] vs. 18.3 [12.9-37.1] cells/µL, P < 0.001). In the multivariable regression analysis, the independent predictor of post-dose change in PMPs was statin therapy (HR −0.43; 95% CI −0.75,−0.10, P = 0.011). The post-dose change in EMPs was also predicted by statin therapy (HR −0.34; 95% CI −0.69, −0.01, P = 0.046). This study showed an increase in both EMPs and PMPs at the peak plasma concentration of rivaroxaban. Statins have promising potential in the prevention of rivaroxaban-related PMP and EMP release. The pro-thrombotic role of PMPs and EMPs during rivaroxaban therapy requires further study.

Systemic and topical administration of spermidine accelerates skin wound healing

BACKGROUND

The skin wound healing process is regulated by various cytokines, chemokines, and growth factors. Recent reports have demonstrated that spermine/spermidine (SPD) promote wound healing through urokinase-type plasminogen activator (uPA)/uPA receptor (uPAR) signaling in vitro. Here, we investigated whether the systemic and topical administration of SPD would accelerate the skin wound-repair process in vivo.

METHODS

A skin wound repair model was established using C57BL/6 J mice. SPD was mixed with white petrolatum for topical administration. For systemic administration, SPD mixed with drinking water was orally administered. Changes in wound size over time were calculated using digital photography.

RESULTS

Systemic and topical SPD treatment significantly accelerated skin wound healing. The administration of SPD promoted the uPA/uPAR pathway in wound sites. Moreover, topical treatment with SPD enhanced the expression of IL-6 and TNF-α in wound sites. Scratch and cell proliferation assays revealed that SPD administration accelerated scratch wound closure and cell proliferation in vitro.

CONCLUSION

These results indicate that treatment with SPD promotes skin wound healing through activation of the uPA/uPAR pathway and induction of the inflammatory response in wound sites. The administration of SPD might contribute to new effective treatments to accelerate skin wound healing. Video Abstract.

Residual risk reduction opportunities in patients with chronic coronary syndrome. Role of dual pathway inhibition

INTRODUCTION

In this review, the role of the rivaroxaban-plus-aspirin approach (dual pathway inhibition - DPI) in patients with chronic coronary syndrome (CCS) and to perform practical recommendations about its use was updated.

AREAS COVERED

The contents of this review were proposed in an expert meeting. To identify relevant articles, a systematic search of Medline/Embase was performed (to July 2019), using the key words 'rivaroxaban', 'vascular dose', 'COMPASS' and 'coronary artery disease' in the search strategy.

EXPERT OPINION

Despite current antithrombotic strategies (single/dual antiplatelet therapy) have decreased rates of recurrent cardiovascular events among patients with CCS, residual risk remains unacceptably high. The COMPASS trial showed in CCS patients that compared with aspirin 100 mg rivaroxaban 2.5 mg bid plus aspirin 100 mg reduced the risk of major cardiac events, cardiovascular hospitalization and mortality, without an increase of intracranial or fatal bleedings. Importantly, residual risk with the rivaroxaban plus aspirin approach was lower than with different dual antiplatelet therapy regimens. The rivaroxaban plus aspirin strategy is of particular benefit in patients with CCS and high-risk cardiovascular feature (i.e. ≥2 vascular beds, heart failure, renal insufficiency, peripheral artery disease, previous stroke or diabetes) and should be considered in these populations.

Rivaroxaban improves vascular response in LPS-induced acute inflammation in experimental models

Rivaroxaban (RVX) was suggested to possess anti-inflammatory and vascular tone modulatory effects. The goal of this study was to investigate whether RVX impacts lipopolysaccharide (LPS)-induced acute vascular inflammatory response. Male rats were treated with 5 mg/kg RVX (oral gavage) followed by 10 mg/kg LPS i.p injection. Circulating levels of IL-6, MCP-1, VCAM-1, and ICAM-1 were measured in plasma 6 and 24 hours after LPS injection, while isolated aorta was used for gene expression analysis, immunohistochemistry, and vascular tone evaluation. RVX pre-treatment significantly reduced LPS mediated increase after 6h and 24h for IL-6 (4.4±2.2 and 2.8±1.7 fold), MCP-1 (1.4±1.5 and 1.3±1.4 fold) VCAM-1 (1.8±2.0 and 1.7±2.1 fold). A similar trend was observed in the aorta for iNOS (5.5±3.3 and 3.3±1.9 folds reduction, P<0.01 and P<0.001, respectively), VCAM-1 (1.3±1.2 and 1.4±1.3 fold reduction, P<0.05), and MCP-1 (3.9±2.2 and 1.9±1.6 fold reduction, P<0.01). Moreover, RVX pre-treatment, improved LPS-induced PE contractile dysfunction in aortic rings (Control vs LPS, Emax reduction = 35.4 and 31.19%, P<0.001; Control vs LPS+RVX, Emax reduction = 10.83 and 11.48%, P>0.05, respectively), resulting in 24.5% and 19.7% change in maximal constriction in LPS and LPS+RVX respectively. These data indicate that RVX pre-treatment attenuates LPS-induced acute vascular inflammation and contractile dysfunction.

Apixaban Downregulates Endothelial Inflammatory and Prothrombotic Phenotype in an In Vitro Model of Endothelial Dysfunction in Uremia

PURPOSE

Chronic kidney disease (CKD) associates with inflammatory and prothrombotic phenotypes, resulting in higher cardiovascular risk. Factor Xa displays functions beyond coagulation, exhibiting proinflammatory effects. The aim of the present study was to investigate whether a direct FXa inhibitor protects from the endothelial dysfunction (ED) caused by uremia.

METHODS

Macro (HUVEC) and microvascular (HMEC) endothelial cells (ECs) were exposed to serum from uremic patients or healthy donors, in absence and presence of apixaban (60 ng/ml). We evaluated changes in surface VCAM-1 and ICAM-1, intracellular eNOS, reactive oxygen species (ROS), and von Willebrand Factor (VWF) production by immunofluorescence, reactivity of the extracellular matrix (ECM) towards platelets, and intracellular signaling.

RESULTS

ECs exposed to uremic serum triggered dysregulation of all the parameters. Presence of apixaban resulted in decreased expression of VCAM-1 (178 ± 14 to 89 ± 2% on HMEC and 324 ± 71 to 142 ± 25% on HUVEC) and ICAM-1 (388 ± 60 to 111 ± 10% on HMEC and 148 ± 9% to 90 ± 7% on HUVEC); increased eNOS (72 ± 8% to 95 ± 10% on HMEC); normalization of ROS levels (173 ± 21 to 114 ± 13% on HMEC and 165 ± 14 to 127 ± 7% on HUVEC); lower production of VWF (168 ± 14 to 92 ± 4% on HMEC and 151 ± 22 to 99 ± 11% on HUVEC); and decreased platelet adhesion onto ECM (134 ± 22 to 93 ± 23% on HMEC and 161 ± 14 to 117 ± 7% on HUVEC). Apixaban inhibited p38MAPK and p42/44 activation in HUVEC (139 ± 15 to 48 ± 15% and 411 ± 66 to 177 ± 57%, respectively) (p < 0.05 vs control for all parameters).

CONCLUSION

Anti-FXa strategies, such as apixaban, prevented ED caused by the uremic milieu, exhibiting anti-inflammatory and antioxidant properties and modulating the reactivity of the ECM.

Reducing residual thrombotic risk in patients with peripheral artery disease: impact of the COMPASS trial

Patients with peripheral artery disease (PAD) are at a high risk not only for the classical cardiovascular (CV) outcomes (major adverse cardiovascular events; MACE) but also for vascular limb events (major adverse limb events; MALE). Therefore, a comprehensive approach for these patients should include both goals. However, the traditional antithrombotic approach with only antiplatelet agents (single or dual antiplatelet therapy) does not sufficiently reduce the risk of recurrent thrombotic events. Importantly, the underlying cause of atherosclerosis in patients with PAD implies both platelet activation and the initiation and promotion of coagulation cascade, in which Factor Xa plays a key role. Therefore, to reduce residual vascular risk, it is necessary to address both targets. In the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) trial that included patients with stable atherosclerotic vascular disease, the rivaroxaban plus aspirin strategy (versus aspirin) markedly reduced the risk of both CV and limb outcomes, and related complications, with a good safety profile. In fact, the net clinical benefit outcome composed of MACE; MALE, including major amputation, and fatal or critical organ bleeding was significantly reduced by 28% with the COMPASS strategy, (hazard ratio: 0.72; 95% confidence interval: 0.59-0.87). Therefore, the rivaroxaban plus aspirin approach provides comprehensive protection and should be considered for most patients with PAD at high risk of such events.

Dual Pathway Inhibition for Vascular Protection in Patients with Atherosclerotic Disease: Rationale and Review of the Evidence

Despite advances in secondary prevention strategies in patients with cardiovascular disease, the residual risk of recurrent atherothrombotic events remains high. Dual-antiplatelet therapy is the standard of care for secondary prevention in patients with acute coronary syndrome (ACS), whereas single antiplatelet therapy, generally with aspirin, is the standard of care for secondary prevention in stable patients with coronary artery disease (CAD), peripheral artery disease (PAD), or cerebrovascular disease. However, atherosclerotic plaque disruption not only triggers platelet activation but also results in thrombin generation because of tissue factor exposure. Therefore, blocking both pathways by combining antiplatelet therapy with an anticoagulant, or dual pathway inhibition (DPI), has the potential to be more effective than inhibiting either pathway alone. The benefit of DPI has been demonstrated in the ATLAS ACS 2-TIMI 51, COMPASS, and VOYAGER PAD trials, where the combination of rivaroxaban vascular dose (2.5 mg twice daily) plus aspirin significantly reduced the risk of atherothrombotic events compared with aspirin across a broad range of patients, including those with recent ACS, those with chronic CAD and/or PAD, and patients with PAD who have undergone peripheral revascularization. This article provides the rationale for this regimen in more detail, including why the DPI regimen with the rivaroxaban vascular dose was developed for vascular protection in a broad spectrum of patients with atherosclerotic disease.

Edoxaban's contribution to key endothelial cell functions

BACKGROUND

We aimed to study the effects of the new oral anticoagulant edoxaban, a factor X activated (FXa) inhibitor, on key endothelial functions that could contribute to cardiovascular benefit.

METHODS

Human umbilical endothelial cells (HUVEC) were obtained from donated umbilical cords and used to analyse 1) structural functions like cell proliferation, migration, and angiogenesis in appropriate assays; 2) anti-inflammatory reactions as mononuclear cell (PBMC) or platelet adhesion to HUVEC monolayers; and 3) haemostasis control by fibrin formation or plasminogen activator modulation. Key molecular effectors and signalling pathways on each function were explored by profiled protein arrays, mRNA, or protein expression analyses.

RESULTS

Edoxaban promoted viability and growth in HUVEC cultures, as well as counteracted the promigratory and antiangiogenic effects of FXa, through action on the PI3K/AKT pathway. Edoxaban inhibited the adhesion to endothelial cells and the transmigration through endothelial monolayers of PBMC, and even counteracted the action of pro-inflammatory stimuli such as FXa by blocking the FXa-induced expression of cell adhesion molecules via the PAR 1-2/PI3K/NF-kB pathway. Haemostatic control of edoxaban could be exerted from the endothelium by the reduction of platelets' adhesion to endothelial cells and the possible acute activation of urokinase plasminogen activator.

CONCLUSIONS

Edoxaban is a safe and structural stabilizing factor for endothelial cells and also has remarkable anti-inflammatory action, preventing PBMC adhesion and transmigration through the endothelium. It may also contribute to haemostasis control by reducing platelet adhesion. Its main molecular mechanism seems to be the control of the PI3K/NF-κB pathways.

Impaired Spontaneous/Endogenous Fibrinolytic Status as New Cardiovascular Risk Factor?: JACC Review Topic of the Week

Endogenous fibrinolysis is a powerful natural defense mechanism against lasting arterial thrombotic occlusion. Recent prospective studies have shown that impaired endogenous fibrinolysis (or hypofibrinolysis) can be detected in a significant number of patients with acute coronary syndrome (ACS) using global assays and is a strong marker of future cardiovascular risk. This novel risk biomarker is independent of traditional cardiovascular risk factors and unaffected by antiplatelet therapy. Most prospective prognostic data have been obtained using a global assay using native whole blood at high shear or plasma turbidimetric assays, which are described herein. Tests of endogenous fibrinolysis could be used to identify patients with ACS who, despite antiplatelet therapy, remain at high cardiovascular risk. This review discusses the impact of currently available medications and those in development that favorably modulate fibrinolytic status and may offer a potential new avenue to improve outcomes in ACS.

The Protective Effect of Dabigatran and Rivaroxaban on DNA Oxidative Changes in a Model of Vascular Endothelial Damage with Oxidized Cholesterol

Background: Atherosclerotic plaques are unstable, and their release may result in thrombosis; therefore, currently, antiplatelet therapy with anticoagulants is recommended for the treatment of acute coronary syndrome. The aim of this study was to assess the effect of oxidized cholesterol on human umbilical vascular endothelial cells (HUVECs). The study also examines the protective and repairing effect of dabigatran and rivaroxaban in a model of vascular endothelial damage with 25-hydroxycholesterol (25-OHC). Methods: HUVECs were treated with compounds induce DNA single-strand breaks (SSBs) using the comet assay. Oxidative DNA damage was detected using endonuclease III (Nth) or human 8 oxoguanine DNA glycosylase (hOOG1). Reactive oxygen species (ROS) formation was determined using flow cytometry. Results: 25-hydroxycholesterol caused DNA SSBs, induced oxidative damage and increased ROS in the HUVECs; ROS level was lowered by dabigatran and rivaroxaban. Only dabigatran was able to completely repair the DNA SSBs induced by oxysterol. Dabigatran was able to reduce the level of oxidative damage of pyrimidines induced by oxysterol to the level of control cells. Conclusions: Observed changes strongly suggest that the tested anticoagulants induced indirect repair of DNA by inhibiting ROS production. Furthermore, dabigatran appears to have a higher antioxidant activity than rivaroxaban.

Dual-pathway inhibition for secondary and tertiary antithrombotic prevention in cardiovascular disease

Advances in antiplatelet therapies for patients with cardiovascular disease have improved patient outcomes over time, but the challenge of balancing the risks of ischaemia and bleeding remains substantial. Moreover, many patients with cardiovascular disease have a residual risk of ischaemic events despite receiving antiplatelet therapy. Therefore, novel strategies are needed to prevent clinical events through mechanisms beyond platelet inhibition and with an acceptable associated risk of bleeding. The advent of non-vitamin K antagonist oral anticoagulants, which attenuate fibrin formation by selective inhibition of factor Xa or thrombin, has renewed the interest in dual-pathway inhibition strategies that combine an antiplatelet agent with an anticoagulant drug. In this Review, we highlight the emerging pharmacological rationale and clinical development of dual-pathway inhibition strategies for the prevention of atherothrombotic events in patients with different manifestations of cardiovascular disease, such as coronary artery disease, cerebrovascular disease and peripheral artery disease.

Rivaroxaban, a specific FXa inhibitor, improved endothelium-dependent relaxation of aortic segments in diabetic mice

Activated factor X (FXa) plays a central role in the coagulation cascade, while it also mediates vascular function through activation of protease-activated receptors (PARs). Here, we examined whether inhibition of FXa by rivaroxaban, a direct FXa inhibitor, attenuates endothelial dysfunction in streptozotocin (STZ)-induced diabetic mice. Induction of diabetes increased the expression of a major FXa receptor, PAR2, in the aorta (P < 0.05). Administration of rivaroxaban (10 mg/kg/day) to diabetic wild-type (WT) mice for 3 weeks attenuated endothelial dysfunction as determined by acetylcholine-dependent vasodilation compared with the control (P < 0.001), without alteration of blood glucose level. Rivaroxaban promoted eNOS^Ser1177 phosphorylation in the aorta (P < 0.001). Induction of diabetes to PAR2-deficient (PAR2^−/−) mice did not affect endothelial function and eNOS^Ser1177 phosphorylation in the aorta compared with non-diabetic PAR2^−/− mice. FXa or a PAR2 agonist significantly impaired endothelial function in aortic rings obtained from WT mice, but not in those from PAR2^−/− mice. FXa promoted JNK phosphorylation (P < 0.01) and reduced eNOS^Ser1177 phosphorylation (P < 0.05) in human coronary artery endothelial cells (HCAEC). FXa-induced endothelial dysfunction in aortic rings (P < 0.001) and eNOS^Ser1177 phosphorylation (P < 0.05) in HCAEC were partially ameliorated by a JNK inhibitor. Rivaroxaban ameliorated diabetes-induced endothelial dysfunction. Our results suggest that FXa or PAR2 is a potential therapeutic target.

Potentiation of thrombus instability: a contributory mechanism to the effectiveness of antithrombotic medications

The stability of an arterial thrombus, determined by its structure and ability to resist endogenous fibrinolysis, is a major determinant of the extent of infarction that results from coronary or cerebrovascular thrombosis. There is ample evidence from both laboratory and clinical studies to suggest that in addition to inhibiting platelet aggregation, antithrombotic medications have shear-dependent effects, potentiating thrombus fragility and/or enhancing endogenous fibrinolysis. Such shear-dependent effects, potentiating the fragility of the growing thrombus and/or enhancing endogenous thrombolytic activity, likely contribute to the clinical effectiveness of such medications. It is not clear how much these effects relate to the measured inhibition of platelet aggregation in response to specific agonists. These effects are observable only with techniques that subject the growing thrombus to arterial flow and shear conditions. The effects of antithrombotic medications on thrombus stability and ways of assessing this are reviewed herein, and it is proposed that thrombus stability could become a new target for pharmacological intervention.

Rivaroxaban: searching the integral vascular protection

INTRODUCTION

Residual cardiovascular risk remains high in patients with atherosclerotic cardiovascular disease despite current antithrombotic therapy. On the other hand, patients with atrial fibrillation have an increased risk of myocardial infarction and cardiovascular death. As a result, a new antithrombotic approach appears necessary to reduce this risk. Areas covered: In this article, the role of rivaroxaban on vascular protection in patients with cardiovascular disease and/or atrial fibrillation was reviewed, with a particular focus, but not limited, on clinical trials. Expert commentary: Previous data have shown that factor Xa plays a key role in the etiopathogenesis of atherothrombosis. Experimental data suggest that rivaroxaban exhibits antiinflammatory and antioxidative stress properties, and may improve endothelial dysfunction. The COMPASS trial showed that among patients with stable atherosclerotic vascular disease, the addition of rivaroxaban 2.5 mg twice daily (vascular dose) to aspirin provided a higher cardiovascular protection than aspirin alone. In ROCKET-AF trial, compared with warfarin, rivaroxaban 20 mg once daily (15 mg if moderate renal dysfunction) (anticoagulant dose) was, at least, as effective as warfarin for the prevention of stroke or systemic embolism among patients with nonvalvular atrial fibrillation, with a trend toward a reduction in the risk of cardiovascular outcomes. All these data suggest that rivaroxaban might have a vascular protective effect beyond its stroke/systemic embolism preventive activity.

Anticoagulation in Patients with Ischaemic Heart Disease and Peripheral Arterial Disease: Clinical Implications of COMPASS Study

Patients with established cardiovascular disease may suffer further cardiovascular events, despite receiving optimal medical treatment. Although platelet inhibition plays a central role in the prevention of new events, the use of anticoagulant therapies to reduce events in atheromatous disease has, until recently, been overlooked. The recent Rivaroxaban for the Prevention of Major Cardiovascular Events in Coronary or Peripheral Artery Disease (COMPASS) study showed an important reduction in cardiovascular events without increasing the risk of fatal and intracranial bleeding when using rivaroxaban, a novel oral anticoagulant, combined with aspirin. This article reviews the available evidence regarding the use of anticoagulant therapies for prevention of cardiovascular events, the results of the COMPASS study and how these results may affect patient management in everyday clinical practice.

Protective, repairing and fibrinolytic effects of rivaroxaban on vascular endothelium

AIMS

Rivaroxaban, a direct inhibitor of activated factor X (FXa), is the only new oral anticoagulant approved for secondary prevention after acute coronary syndrome. Our objective was to identify the possible molecular mechanisms of rivaroxaban that contribute to endothelial function.

METHODS

Cell viability and growth of human umbilical vein endothelial cells (HUVEC) were registered. Gene expression studies comparing the effects of rivaroxaban and FXa were conducted by a selective RNA array and confirmed by protein quantification. Wound-healing experiments on HUVEC, platelet adhesion, enzymatic activity, and cell-based assays for fibrin formation were performed with rivaroxaban.

RESULTS

Rivaroxaban (50 nM) only altered (>2 fold change) the expression of matrix metallopeptidase 2 and urokinase plasminogen activator (u-PA), but counteracted the FXa (9 nM)-induced upregulation of several pro-inflammatory genes (P < 0.05) and FXa-enhanced platelet adhesion over HUVEC. Rivaroxaban increased u-PA protein expression in HUVEC supernatants and enhanced u-PA activity (up to 4 IU ng^-1 of u-PA). Rivaroxaban (1 nM-1 μM) showed a significant and dose-dependent positive effect on HUVEC growth that was inhibited by BC-11-hydroxibromide, an inhibitor of u-PA. Healing properties after a wound on HUVEC cultures, and fibrinolytic properties were also shown by rivaroxaban. Both effects were reversed by BC-11-hydroxibromide.

CONCLUSIONS

Rivaroxaban enhanced viability, growth and migration of HUVEC, mainly by u-PA activation and upregulation, which also participate in the rivaroxaban-induced fibrinolytic activity at endothelial level. Rivaroxaban also protected from the pro-inflammatory effects of FXa on HUVEC. Altogether may improve endothelial functionality and could contribute to the cardiovascular benefits of rivaroxaban.