Oral Antiplatelet Therapy for Secondary Prevention of Acute Coronary Syndrome

Non-clinical investigations about cytotoxic and anti-platelet activities of gamma-terpinene

Gamma-terpinene (γ-TPN) is a cyclohexane monoterpene isolated from plant essential oils, such as tea tree (Melaleuca alternifolia), oregano (Origanum vulgare), rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris Marchand), and eucalyptus (Eucalyptus sp.). Terpenes are widely studied molecules pharmacologically active on the cardiovascular system, hemostasis, and antioxidant actions. Herein, it was investigated the cytotoxic and antiplatelet activity of γ-TPN using different non-clinical laboratory models. For in silico evaluation, the PreADMET, SwissADME, and SwissTargetPrediction softwares were used. Molecular docking was performed using the AutoDockVina and BIOVIA Discovery Studio databases. The cytotoxicity of γ-TPN was analyzed by the MTT assay upon normal murine endothelial SVEC4-10 and fibroblast L-929 cells. Platelet aggregation was evaluated with platelet-rich (PRP) and platelet-poor (PPP) plasma from spontaneously hypertensive rats (SHR), in addition to SVEC4-10 cells pre-incubated with γ-TPN (50, 100, and 200 µM) for 24 h. SHR animals were pre-treated by gavage with γ-TPN for 7 days and divided into four groups (negative control, 25, 50, and 100 mg/kg). Blood samples were collected to measure nitrite using the Griess reagent. Gamma-TPN proved to be quite lipid-soluble (Log P = +4.50), with a qualified profile of similarity to the drug, good bioavailability, and adequate pharmacokinetics. It exhibited affinity mainly for the P2Y12 receptor (6.450 ± 0.232 Kcal/mol), moderate cytotoxicity for L-929 (CC50 = 333.3 µM) and SVEC 4-10 (CC50 = 366.7 µM) cells. The presence of γ-TPN in SVEC 4-10 cells was also able to reduce platelet aggregation by 51.57 and 44.20% at lower concentrations (50 and 100 µM, respectively). Then, γ-TPN has good affinity with purinergic receptors and an effect on the reversal of platelet aggregation and oxidative stress, being promising and safe for therapeutic targets and subsequent studies on the control of thromboembolic diseases.

Drugs targeting adenosine signaling pathways: A current view

Adenosine is an endogenous nucleoside that regulates many physiological and pathological processes. It is derived from either the intracellular or extracellular dephosphorylation of adenosine triphosphate and interacts with cell-surface G-protein-coupled receptors. Adenosine plays a substantial role in protecting against cell damage in areas of increased tissue metabolism and preventing organ dysfunction in pathological states. Targeting adenosine metabolism and receptor signaling may be an effective therapeutic approach for human diseases, including cardiovascular and central nervous system disorders, rheumatoid arthritis, asthma, renal diseases, and cancer. Several lines of evidence have shown that many drugs exert their beneficial effects by modulating adenosine signaling pathways but this knowledge urgently needs to be summarized, and most importantly, actualized. The present review collects pharmaceuticals and pharmacological or diagnostic tools that target adenosine signaling in their primary or secondary mode of action. We overviewed FDA-approved drugs as well as those currently being studied in clinical trials. Among them are already used in clinic A2A adenosine receptor modulators like istradefylline or regadenoson, but also plenty of anti-platelet, anti-inflammatory, or immunosuppressive, and anti-cancer drugs. On the other hand, we investigated dozens of specific adenosine pathway regulators that are tested in clinical trials to treat human infectious and noninfectious diseases. In conclusion, targeting purinergic signaling represents a great therapeutic challenge. The actual knowledge of the involvement of adenosinergic signaling as part of the mechanism of action of old drugs has open a path not only for drug-repurposing but also for new therapeutic strategies.

Best Practices in Pharmacotherapy for Acute Coronary Syndromes

Numerous advances have been made in the therapy of acute coronary syndromes. Despite these advances, acute coronary syndromes still cause significant morbidity and mortality. Decisions as to the best therapy vary depending on other patient factors, such as age, need for chronic anticoagulation, tolerability of medications, and the degree of myocardial damage. Recent evidence suggests that a shorter duration of therapy may be beneficial in decreasing bleeding events without compromising benefits of preventing ischemic complications. For those who have an indication for chronic anticoagulation, less intensive therapy may also be beneficial, again without increasing ischemic complications. Data regarding agents that inhibit the renin–angiotensin–aldosterone system are available and these data are reviewed. Knowledge of the pharmacology, potency, and pharmacokinetics of drugs, as well as adverse drug events, may direct clinicians in choosing the optimal pharmacotherapy strategy for their patients.

MicroRNA sequencing in patients with coronary artery disease – considerations for use as biomarker for thrombotic risk

MicroRNAs (miRNAs) are small RNAs integral in the regulation of gene expression. Analysis of circulating miRNA levels may identify patients with coronary artery disease (CAD) at risk for recurrent myocardial infarction (MI) after percutaneous coronary interventions (PCIs). Subjects with CAD were selected from the GENCATH cardiac catheterization biobank. Subjects with recurrent MI after PCI were compared with those without recurrent MI during follow‐up in the initial (n = 48) and replication cohort (n = 67). Next generation MiRNA sequencing was performed on plasma samples and whole blood samples fixed with PAXGENE tubes upon collection. Overall, 164 miRNAs derived from whole blood were differentially expressed in the replication cohort between subjects with and without recurrent MI events (p < 0.05), with 69 remaining significant after false‐discovery rate (FDR) correction. None of the miRNAs in plasma was significantly different by FDR among subjects with and without MI. Overall, correlation between direction of effects between plasma and whole blood assays was variable, and only two miRNAs were concordant and significant in both. Associations of miRNA with vascular disease, MI, and thrombosis were further explored. MiRNA profiling has potential as the future biomarker for disease prognosis and treatment response marker in secondary treatment of patients with CAD after PCI. Whole blood may be the preferred sample source as compared to plasma.

Incidence of postoperative, major, adverse cardiac events in patients undergoing carotid endarterectomy: A single-center, retrospective study

OBJECTIVE

This study aimed to determine the incidence of postoperative major adverse cardiac events for patients undergoing carotid endarterectomy.

METHODS

This single-center, retrospective study recruited 171 carotid endarterectomy patients between January 1999 and June 2018. Patients who received a carotid endarterectomy in conjunction with other surgery were excluded. The primary outcomes were the incidences of major adverse cardiac events (comprising myocardial infarction, significant arrhythmias, congestive heart failure, and cardiac death) within 7 days, 7-30 days, and > 30 days-1 year, postoperatively. The secondary outcomes were the factors related to major adverse cardiac events and the incidence of postoperative stroke. The patients' charts were reviewed, and direct contact was made with them to obtain information on their status post discharge.

RESULTS

The incidences of major adverse cardiac events within 7 days, 7-30 days, and >30 days-1 year of the carotid endarterectomy were 3.5% of patients (95% confidence interval: 0.008-0.063), 1.2% (95% confidence interval: 0.004-0.028), and 1.8% (95% confidence interval: 0.002-0.037), respectively. The major adverse cardiac events occurring within 7 days were arrhythmia (2.3% of patients), cardiac arrest (1.8%), myocardial infarction (1.2%), and congestive heart failure (1.2%), while the corresponding postoperative stroke rate was 4.7%.

CONCLUSION

The 7-day incidence of major adverse cardiac events after the carotid endarterectomy was 3.5%. The most common major adverse cardiac event during that period was cardiac arrhythmia.

Comparison of Net Clinical Benefit Between Clopidogrel and Ticagrelor Following Percutaneous Coronary Intervention in Patients in China With Acute Coronary Syndrome

INTRODUCTION

The objective of the present study was to evaluate the difference in net clinical benefit of clopidogrel plus aspirin compared with ticagrelor plus aspirin after 12 months in patients in mainland China with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) with newer-generation drug-eluting stents (DESs).

METHODS

In this multicenter, retrospective, real-world study, the data were sourced from three databases: BRIC-ACS(I) study, COSTIC study, and 301 Hospital PCI patient database from January 2014 to October 2017. The primary endpoint of the study was net adverse clinical and cerebral events (NACCE) comprised of all-cause death, non-fatal myocardial infarction (MI), non-fatal stroke or Bleeding Academic Research Consortium (BARC) type ≥ 2 (excluding BARC type = 4) bleeding, whereas the secondary end point was evaluation of major adverse cardiovascular events (MACE) and BARC type ≥ 2 bleeding events.

RESULTS

A total of 7862 ACS patients were included in the final analysis, of whom propensity score matching (PSM) analysis yielded 2165 patients in each cohort. After PSM analysis, cumulative incidence of NACCE was significantly lower with clopidogrel and aspirin than with ticagrelor and aspirin [117 (5.4%) vs. 180 (8.3%), P < 0.001] at 12 months. Effect estimates showed reduced risk of NACCE occurrence in patients treated with clopidogrel and aspirin [adjusted hazard ratio (aHR): 0.61, 95% CI 0.48-0.77, P < 0.001]. Incidence of bleeding was significantly lower in the clopidogrel cohort than in the ticagrelor cohort (aHR: 0.48, 95% CI 0.35-0.66, P < 0.001). Clopidogrel and aspirin therapy was comparable to ticagrelor and aspirin in reducing the incidence of MACE after PSM analysis.

CONCLUSION

In Chinese ACS patients who underwent PCI with second-generation DESs, outpatient use of clopidogrel dual antiplatelet therapy (DAPT) was associated with reduction in NACCE and bleeding.

An update of the efficacy and comparative characteristics of direct (new) oral anticoagulants (DOACs)

Direct (New-generation) Oral Anticoagulants (DOACs) have emerged as effective agents which are used in place of vitamin-K antagonists in treatment and prophylaxis of Venous Thromboembolism (VTE), atrial fibrillation and other thrombotic diseases. Among them, the FIIa-direct thrombin inhibitor dabigatran and FXa inhibitors (rivaroxaban, apixaban, edoxaban) are the most broadly used. Anticoagulant dosing may differ under special considerations. The patients' physiological reserves, organ functional status and failures should be taken into account in clinical decision-making processes. The advantages and drawbacks of each specific agent should be weighed with special regard to metabolism, pharmacokinetics and pharmacodynamics, along with the efficiency of the agents in different indications. This article aims to review the most recent literature to highlight the usage and efficacy of the agents in different clinical conditions.

Vorapaxar-modified polysulfone membrane with high hemocompatibility inhibits thrombosis

Hemodialysis therapy is intended for patients suffering from renal insufficiency, pancreatitis, and other serious diseases. Platelets are an important active ingredient in the thrombosis induced by hemodialysis membranes. So far, there are few studies of hemodialysis membranes focusing on the effects of protease-activated receptor 1 (PAR1) activation on the platelet membrane. Among various antithrombotic agents, vorapaxar is a novel PAR1 inhibitor with high efficacy. In this study, we constructed a vorapaxar-modified polysulfone (VMPSf) membrane using immersion-precipitation phase transformation methods and characterized the microstructure in terms of hydrophilicity and mechanical properties. The water contact angle of the VMPSf membrane was 22.45% lower than that of the PSf membrane. A focused determination of platelet morphology was obtained using scanning electron microscopy. Meanwhile, we evaluated the effects of a VMPSf membrane on platelet adhesion. We observed that the VMPSf membrane could reduce the number of adhered platelets without altering their spherical or elliptical shape. The PAR1 levels in VMPSf membranes were 7.4 MFI lower than those in PSf membranes, suggesting that this modified membrane can effectively inhibit platelet activation. Activated partial thromboplastin time (APTT, 5.3 s extension) and thrombin time (TT, 2.1 s extension) reflect good anticoagulant properties. Recalcification time (80.6 s extension) and fibrinogen adsorption (9.9 μg/cm² reduction) were related to antithrombotic properties. To determine the biosafety of VMPSf membranes, we investigated antianaphylactic and anti-inflammatory properties in vitro and acute toxicity in vivo, it was obvious that C3a and C5a had decreased to 9.6 and 0.8 ng/mL, respectively. The results indicated that the VMPSf membrane has potential for clinical application.

Expression and Clinical Prognostic Value of Platelet NLRP3 in Acute Coronary Syndrome

Purpose

Little is known about the relationship between the level of platelet NOD-like receptor protein 3 (NLRP3) and the severity of acute coronary syndrome (ACS) or the prognostic value of platelet NLRP3 for percutaneous coronary intervention (PCI).

Methods

Platelets collected from 25 healthy subjects, 23 patients with stable angina pectoris (SAP), and 72 patients with ACS were analyzed by Western blotting and real-time fluorescence quantitative PCR (qPCR). A total of 152 patients with ACS who had undergone PCI were included in this study to evaluate the prognostic value of platelet NLRP3.

Results

The levels of platelet NLRP3 in both the healthy and SAP groups were clearly lower than in the ACS group (P<0.001). According to the Pearson correlation analysis, the expression of platelet NLRP3 was closely related to the mean platelet volume (MPV), left ventricular ejection fraction (LVEF), the Gensini score, and the Global Registry of Acute Coronary Events (GRACE) score (all P<0.001). Multivariate logistic regression analysis identified NLRP3 as an independent risk factor for adverse cardiovascular events (ACEs) after PCI (P=0.004). The proportion of patients with high NLPR3 expression (the NLRP3-high group) remaining free of adverse events for 3 years was remarkably lower than that in patients with low NLPR3 expression (the NLRP3-low group; P=0.024). The NLRP3-high group had a significantly higher proportion of patients with interleukin-1β–expressing (20.4%±6.1%) platelets than the NLRP3-low group (10.7%±3.5%, P<0.001). Moreover, the NLRP3-high group exhibited higher platelet activity, as indicated by increased PAC-1 binding and CD62P expression, compared with the NLRP3-low group (P<0.001).

Conclusion

These results indicated that platelet NLRP3 was a novel potential prognostic factor for patients with ACS that underwent PCI.

Effect of Ticagrelor on Reducing the Risk of Gram-Positive Infections in Patients With Acute Coronary Syndrome

In light of recent studies describing the antibacterial properties of ticagrelor, the association between treatment with ticagrelor and subsequent risk for infection following acute coronary syndrome (ACS) is taking on increased importance. A single center, retrospective, matched cohort analysis was performed. All patients older than 30 years of age admitted between January 1, 2013 and November 1, 2019 for an ACS and discharged with dual antiplatelet therapy (DAPT) were included. The primary outcome was defined as hospital admissions due to infections likely caused by gram-positive bacteria up to 1 year following the ACS hospitalization. The base cohort included 3,909 patients. About 2,035 (52.1%) were treated with ticagrelor and 1,874 (47.9%) with clopidogrel. Patients treated with ticagrelor had a 64% lower risk of gram-positive infection during the first year following hospitalization after adjusting for demographic and co-morbidity factors compared with those treated with clopidogrel (hazard ratio [HR], 0.36; 95% confidence interval [CI], 0.21 to 0.61; p <0.001). In a cohort starting from 1 year (conclusion of DAPT period) and up to 3 years following ACS hospitalization, the risk of gram-positive infection was comparable in both groups (HR, 0.70; 95% CI, 0.41 to 1.19; p = 0.182). Treatment with ticagrelor was not associated with a reduced risk of gram-negative infections (HR, 0.48; 95% CI, 0.21 to 1.06; p = 0.07). In conclusion, DAPT regimen that includes aspirin and ticagrelor is associated with reduced risk of gram-positive infection compared with the combination of aspirin and clopidogrel.