Acetylsalicylic Acid Reduces Passive Aortic Wall Stiffness and Cardiovascular Remodelling in a Mouse Model of Advanced Atherosclerosis

Acetylsalicylic acid (ASA) is widely used in secondary prevention of cardiovascular (CV) disease, mainly because of its antithrombotic effects. Here, we investigated whether ASA can prevent the progression of vessel wall remodelling, atherosclerosis, and CV complications in apolipoprotein E deficient (ApoE−/−) mice, a model of stable atherosclerosis, and in ApoE−/− mice with a mutation in the fibrillin-1 gene (Fbn1C1039G+/−), which is a model of elastic fibre fragmentation, accompanied by exacerbated unstable atherosclerosis. Female ApoE−/− and ApoE−/−Fbn1C1039G+/− mice were fed a Western diet (WD). At 10 weeks of WD, the mice were randomly divided into four groups, receiving either ASA 5 mg/kg/day in the drinking water (ApoE−/− (n = 14), ApoE−/−Fbn1C1039G+/− (n = 19)) or plain drinking water (ApoE−/− (n = 15), ApoE−/−Fbn1C1039G+/− (n = 21)) for 15 weeks. ApoE−/−Fbn1C1039G+/− mice showed an increased neutrophil–lymphocyte ratio (NLR) compared to ApoE−/− mice, and this effect was normalised by ASA. In the proximal ascending aorta wall, ASA-treated ApoE−/−Fbn1C1039G+/− mice showed less p-SMAD2/3 positive nuclei, a lower collagen percentage and an increased elastin/collagen ratio, consistent with the values measured in ApoE−/− mice. ASA did not affect plaque progression, incidence of myocardial infarction and survival of ApoE−/−Fbn1C1039G+/− mice, but systolic blood pressure, cardiac fibrosis and hypertrophy were reduced. In conclusion, ASA normalises the NLR, passive wall stiffness and cardiac remodelling in ApoE−/−Fbn1C1039G+/− mice to levels observed in ApoE−/− mice, indicating additional therapeutic benefits of ASA beyond its classical use.

Antiplatelet and Antithrombotic Effects of Isaridin E Isolated from the Marine-Derived Fungus via Downregulating the PI3K/Akt Signaling Pathway

Isaridin E, a cyclodepsipeptide isolated from the marine-derived fungus Amphichorda felina (syn. Beauveria felina) SYSU-MS7908, has been demonstrated to possess anti-inflammatory and insecticidal activities. Here, we first found that isaridin E concentration-dependently inhibited ADP-induced platelet aggregation, activation, and secretion in vitro, but did not affect collagen- or thrombin-induced platelet aggregation. Furthermore, isaridin E dose-dependently reduced thrombosis formation in an FeCl3-induced mouse carotid model without increasing the bleeding time. Mechanistically, isaridin E significantly decreased the ADP-mediated phosphorylation of PI3K and Akt. In conclusion, these results suggest that isaridin E exerts potent antithrombotic effects in vivo without increasing the risk of bleeding, which may be due to its important role in inhibiting ADP-induced platelet activation, secretion and aggregation via the PI3K/Akt pathways.

Abstract 11269: Recombinant Soluble Thrombomodulin in Prolonged Porcine Cardiac Arrest

Introduction: Sudden Cardiac Arrest (CA) affects more than 400,000 people per year in the United States. Although a third of these patients survive to hospital admission, another 60-70% go on to die due to failed recovery of vital organ function. Microvascular thrombosis has been suggested as a potential contributor to prolonged organ dysfunction, but no antithrombotic therapies have been shown to be beneficial and coagulofibrinolytic abnormalities in prolonged CA remain poorly understood. Objectives: To establish key biomarkers of porcine coagulation and fibrinolysis in the setting of prolonged CA and cardiopulmonary resuscitation (CPR) and test the ability of ART-123 (recombinant human thrombomodulin alpha) to reverse these abnormalities. Methods: 15 pigs (n=5 per group) underwent 8 minutes of no-flow CA followed by 50 minutes of mechanical CPR. Animals were randomized to receive saline or ART-123 (~1mg/kg) pre-arrest (5 minutes prior to ventricular fibrillation) or post-arrest (2 minutes after initiation of CPR). Results: Robust and ongoing activation of coagulation and fibrinolysis were detected throughout the resuscitation. After 50 minutes of CPR, plasma tests suggested consumptive coagulopathy, while whole blood testing (thromboelastography) indicated a persistent hypercoagulable state. ART-123 had a clear anticoagulant effect irrespective of timing (TAT complexes 381±25 vs. 238±18 vs. 226±12, p<0.01, and d-dimer 4.86±0.54 vs. 2.39±0.2 vs. 2.46±0.21 for vehicle, pre-arrest, post-arrest, p = 0.05). A pro-fibrinolytic effect was also observed, but only when the drug was given before no-flow, with a significant increase in levels of free endogenous tPA (1.2±0.12 vs. 3.29±0.29 vs. 1.72±0.3, p < 0.001) and corresponding suppression of free PAI-1 (0.59±0.15 vs. 0.14±0.01 vs. 0.41±0.09, p < 0.001). Conclusion: Our porcine CA model provides an excellent platform for evaluating antithrombotic interventions. Plasma testing after prolonged CA/CPR suggests consumptive coagulopathy, although TEG indicates a persistent hypercoagulable state. ART-123 given before no-flow or just after CPR demonstrates antithrombotic effects, although the specific modes of action depending on the timing of administration.

GPVI inhibition by glenzocimab synergistically inhibits atherosclerotic plaque-induced platelet activation when combined with conventional dual antiplatelet therapy

Introduction Aspirin and a potent platelet P2Y12 inhibitor, such as prasugrel or ticagrelor, are not always sufficient to prevent thrombus formation in patients with ST-elevation MI (STEMI), leading to “slow flow” or “no reflow” effects after stenting. GPIIb/IIIa inhibitors, such as eptifibatide, may help in this setting, but are not used routinely due to their bleeding risk. GPVI has critical roles in thrombosis and a minimal role in haemostasis. Here we tested whether depletion of GPVI has effects on thrombus formation after MI in an animal model and investigated the effects of a novel platelet GPVI inhibitor, glenzocimab (a Fab fragment of a monoclonal antibody), on platelet activation and thrombus formation when combined with aspirin and ticagrelor. Methods We used intravital microscopy in a murine model of ST-elevation myocardial infarction and ischaemia-reperfusion injury to investigate microvascular thrombosis. We investigated the antithrombotic effects of adding glenzocimab (previously known as ACT017) to blood from healthy donors and 20 patients with ACS treated with aspirin and ticagrelor. We compared the effect of glenzocimab with the GPIIb/IIIa inhibitor eptifibatide ex-vivo. We stimulated platelets with collagen and atherosclerotic plaque material that was sourced from patients undergoing carotid endarterectomy. We investigated effects on platelet aggregation, spreading, signalling, adhesion, thrombin generation, thrombus formation and clot stability ex vivo. Results Genetic depletion of GPVI in an animal model of myocardial infarction reduced microvascular thrombosis. Ex vivo, aspirin and ticagrelor partially inhibited atherosclerotic plaque-induced platelet aggregation (assessed by multiple electrode aggregometry) by 48% compared to control (34±3 vs. 65±4 U; P&lt;0.001; Figure 1). Atherosclerotic plaque-induced platelet aggregation, adhesion, secretion and activation were critically dependent on platelet GPVI activation and were potently inhibited by glenzocimab. Glenzocimab alone reduced atherosclerotic plaque-induced platelet aggregation by 75% compared to control (16±4 vs. 65±4 U; P&lt;0.001; Figure 1) and by over 95% when combined with aspirin and ticagrelor (3±1 vs 65±4 U; P&lt;0.001; Figure 1). Furthermore, glenzocimab provided multiple synergistic antithrombotic effects when added to the blood of aspirin and ticagrelor-treated patients with ACS ex vivo. Glenzocimab and the GPIIb/IIIa inhibitor, eptifibatide, had many similar antithrombotic effects but glenzocimab had less effect on mechanisms of general haemostasis compared to eptifibatide, as assessed by ROTEM (Figure 2). Conclusions The addition of glenzocimab to aspirin and ticagrelor provides synergistic inhibition of multiple critical mechanisms of atherothrombosis. Glenzocimab and the GPIIb/IIIa inhibitor, eptifibatide, share many similar antithrombotic effects, although glenzocimab has less impact on mechanisms involved in haemostasis compared to eptifibatide. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Academy of Medical Sciences UK Clinical Lecturer Starter GrantRoyal Embassy of Saudi Arabia

Traditional Chinese medicine in the treatment of high incidence diseases in cold areas: the thrombotic diseases

Thrombotic diseases are the leading causes of death worldwide, especially in cold climates. Traditional Chinese medicine (TCM)-based therapies have gained increasing popularity worldwide, but also raised some concerns about its efficacy, safety profile and exact mechanisms. TCM has been traditionally used in the management of thrombosis and convincingly proven effective in modifying thrombosis progression, particularly the platelet function, coagulation system and fibrinolytic system. This review article focuses on TCM regulation of thrombosis with brief discussion on the fundamental aspects and relevant background information for better understanding of the subject. In addition to its antithrombotic effects, we will dive insight into the cellular and molecular mechanisms of TCM as pharmacological regulators of platelet aggregation, coagulation, and fibrinolysis. With increasing awareness and understanding of the benefits and potentials of TCM, TCM products will in no doubt gain its broader applications in the treatment of thrombosis and associated disorders, which in turn will deepen our understanding of its pharmacological and molecular mechanisms. Finally, current review provides a perspective view on the future directions to TCM research on thrombosis.

Anti-Diabetic Drugs GLP-1 Agonists and DPP-4 Inhibitors may Represent Potential Therapeutic Approaches for COVID-19

: The fast spread of coronavirus 2019 (COVID-19) calls for immediate action to counter the associated significant loss of human life and deep economic impact. Certain patient populations like those with obesity and diabetes are at higher risk for acquiring severe COVID-19 disease and have a higher risk of COVID-19 associated mortality. In the absence of an effective and safe vaccine, the only immediate promising approach is to repurpose an existing approved drug. Several drugs have been proposed and tested as adjunctive therapy for COVID-19. Among these drugs are the glucagon-like peptide-1 (GLP-1) 2 agonists and the dipeptidylpeptidase-4 (DPP-4) inhibitors. Beyond their glucose-lowering effects, these drugs have several pleiotropic protective properties, which include cardioprotective effects, anti-inflammatory and immunomodulatory activities, antifibrotic effects, antithrombotic effects, and vascular endothelial protective properties. This narrative review discusses these protective properties and addresses their scientific plausibility for their potential use as adjunctive therapy for COVID-19 disease.

Antioxidant, Anti-Inflammatory and Antithrombotic Effects of Ginsenoside Compound K Enriched Extract Derived from Ginseng Sprouts

Partially purified ginsenoside extract (PGE) and compound K enriched extract (CKE) were prepared from ginseng sprouts, and their antioxidant, anti-inflammatory and antithrombotic effects were investigated. Compared to the 6-year-old ginseng roots, ginseng sprouts were found to have a higher content of phenolic compounds, saponin and protopanaxadiol-type ginsenoside by about 56%, 36% and 43%, respectively. PGE was prepared using a macroporous adsorption resin, and compound K(CK) was converted and enriched from the PGE by enzymatic hydrolysis with a conversion rate of 75%. PGE showed higher effects than CKE on radical scavenging activity in antioxidant assays. On the other hand, CKE reduced nitric oxide levels more effectively than PGE in RAW 264.7 cells. CKE also reduced pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1β and IL-6 than PGE. Tail bleeding time and volume were investigated after administration of CKE at 70–150 mg/kg/day to mice. CKE administered group showed a significant increase or increased tendency in bleeding time than the control group. Bleeding volume in the CKE group increased than the control group, but not as much as in the aspirin group. In conclusion, ginseng sprouts could be an efficient source of ginsenoside, and CKE converted from the ginsenosides showed antioxidant, anti-inflammatory and antithrombotic effects. However, it was estimated that the CKE might play an essential role in anti-inflammatory effects rather than antioxidant effects.

Antithrombotic Effects of Montelukast by Targeting Coagulation Factor XIa

Current oral anticoagulants prescribed for the prevention of thrombosis suffer from severe hemorrhagic problems. Coagulation factor XIa (FXIa) has been confirmed as a safer antithrombotic target as intervention with FXIa causes lower hemorrhagic risks. In this study, by a high-throughput virtual screening, we identified Montelukast (MK), an oral antiasthmatic drug, as a potent and specific FXIa inhibitor (IC50 = 0.17 µM). Compared with the two mostly prescribed anticoagulants (Warfarin and Apixaban), MK demonstrated comparable or even higher antithrombotic effects in three independent animal models. More importantly, in contrast to the severe hemorrhage caused by Warfarin or Apixaban, MK did not measurably increase blood loss in vivo. In addition, MK did not affect the hemostatic function in plasma from healthy individuals. In contrast, MK suppressed clot formation in clinical hypercoagulable plasma samples. This study provides a lead compound of anticoagulants targeting FXIa, and suggests the exploratory clinical researches on antithrombotic therapies using MK.