Effects of P2Y12 receptor antagonists beyond platelet inhibition--comparison of ticagrelor with thienopyridines

Ticagrelor increases its own potency at the P2Y12 receptor by directly changing the plasma membrane lipid order in platelets

BACKGROUND AND PURPOSE

Although the amphiphilic nature of the widely used antithrombotic drug Ticagrelor is well known, it was never considered as a membranotropic agent capable of interacting with the lipid bilayer in a receptor-independent way. In this study, we investigated the influence of Ticagrelor on plasma membrane lipid order in platelets and if this modulates the potency of Ticagrelor at the P2Y12 receptor.

EXPERIMENTAL APPROACH

We combined fluorescent in situ, in vitro and in silico approaches to probe the interactions between the plasma membrane of platelets and Ticagrelor. The influence of Ticagrelor on the lipid order of the platelet plasma membrane and large unilamellar vesicles was studied using the advanced fluorescent probe NR12S. Furthermore, the properties of model lipid bilayers in the presence of Ticagrelor were characterized by molecular dynamics simulations. Finally, the influence of an increased lipid order on the dose-response of platelets to Ticagrelor was studied.

KEY RESULTS

Ticagrelor incorporates spontaneously into lipid bilayers and affects the lipid order of the membranes of model vesicles and isolated platelets, in a nontrivial composition and concentration-dependent manner. We showed that higher plasma membrane lipid order in platelets leads to a lower IC50 value for Ticagrelor. It is shown that membrane incorporation of Ticagrelor increases its potency at the P2Y12 receptor, by increasing the order of the platelet plasma membrane.

CONCLUSION AND IMPLICATIONS

A novel dual mechanism of Ticagrelor action is suggested that combines direct binding to P2Y12 receptor with simultaneous modulation of receptor-lipid microenvironment.

Randomised Placebo-Controlled Pilot Trial Evaluating the Anti-Anginal Efficacy of Ticagrelor in Patients with Angina with Nonobstructive Coronary Arteries and Coronary Slow Flow Phenomenon

Background: The coronary slow flow phenomenon (CSFP) is an angiographic finding characterised by the delayed passage of contrast through the coronary arteries, despite the absence of obstructive coronary artery disease (defined as less than 50% narrowing of the vessel lumen). Patients with the CSFP experience recurrent angina, for which there are limited evidence-based therapies. Ticagrelor may serve as an effective anti-anginal therapy for these patients by increasing adenosine levels, which could alleviate coronary microvascular dysfunction and its associated angina due to its vasodilatory properties. This study aimed to determine the anti-anginal efficacy of ticagrelor 90 mg taken twice daily on spontaneous angina episodes in patients with refractory angina (i.e., episodes ≥3/week despite two anti-anginals) and documented CSFP. Methods: In a randomised, double-blind, placebo-controlled, cross-over trial, the anti-anginal efficacy of a 4-week ticagrelor therapy regimen was evaluated in 20 patients with refractory angina (mean age 61.5 ± 10.5 years; 40% women) who had documented slow coronary flow. The primary endpoint was the frequency of angina episodes, recorded using an angina diary. Secondary endpoints included the duration and severity of angina episodes, consumption of short-acting nitrates, and health status evaluations using the Seattle Angina Questionnaire (SAQ) and the Short Form-36 (SF-36) indices. Results: During the four weeks of therapy, ticagrelor did not significantly improve angina symptoms compared to the placebo (placebo 25.7 (16.7)) vs. ticagrelor 19.8 (18.1), p > 0.05). Furthermore, it did not impact other patient-related outcome measures, including angina severity, duration, frequency of prolonged angina episodes, nitrate consumption, or the SAQ/SF-36 health outcome indices. No serious adverse events related to the study drug were observed. Conclusions: In patients with documented CSFP who were unresponsive to standard anti-anginal therapy, ticagrelor did not reduce the frequency of spontaneous angina episodes or the consumption of nitrates. Further confirmation of the potential benefits of this therapy may be obtained through a larger clinical trial.

Ticagrelor potentiates cardioprotection by remote ischemic preconditioning: the ticagrelor in remote ischemic preconditioning (TRIP) randomized clinical trial

OBJECTIVE

Remote ischemic preconditioning (RIPC) reduces periprocedural myocardial injury (PMI) after percutaneous coronary intervention (PCI) through various pathways, including an adenosine-triggered pathway. Ticagrelor inhibits adenosine uptake, thus may potentiate the effects of RIPC. This randomized trial tested the hypothesis that ticagrelor potentiates the effect of RIPC and reduces PMI, assessed by post-procedural troponin release.

METHODS

Patients undergoing PCI for non-ST elevation acute coronary syndromes were 1:1 randomized to ticagrelor (TG-Group) or clopidogrel (CL-Group). Within each treatment, patients were 1:1 randomized to a RIPC (RIPC-Group) or a control group (CTRL-Group). The primary endpoint was the difference between post- and pre-procedural troponin at 24 h following PCI, termed deltaTnI.

RESULTS

During a 12-month period, 138 patients were included in the study (34 in the CL-CTRL group, 34 in the TG-CTRL group, 35 in the CL-RIPC group, and 35 in the TG-CTRL group). There was a significant difference in deltaTnI between the study groups [ TG-RIPC:0.04 (0-0.16), CL-CTRL:0.10 (0.03-0.43), CLRIPC:0.11 (0.03-0.89), and TG-CTRL:0.24 (0.06-0.47); p = 0.007]. Eight patients (22.9%) in the TG-RIPC group developed type 4a myocardial infarction (MI), compared to 14 (40%) in the CL-RIPC group, 13 (38.2%) in the CL-CTRL group, and 19 (55.9%) in the TG-CTRL group (p = 0.048). A significant interaction between antiplatelet group allocation and RIPC on deltaTnI was observed [F (1,134) = 7.509; p = 0.007]. In multivariate analysis, the interaction between RIPC and ticagrelor treatment was independently associated with a lower incidence of Type 4a MI.

CONCLUSION

Our results demonstrate an interaction between ticagrelor and RIPC, which may potentiate the cardioprotective effects of RIPC during PCI by reducing PMI.

Ticagrelor enhances the cardioprotective effects of ischemic preconditioning in stable patients undergoing percutaneous coronary intervention: the TAPER-S randomized study

BACKGROUND

Ticagrelor improves clinical outcomes in patients with acute coronary syndromes compared with clopidogrel. Ticagrelor also inhibits cell uptake of adenosine and has been associated with cardioprotective effects in animal models. We sought to investigate the potential cardioprotective effects of ticagrelor, as compared with clopidogrel, in stable patients undergoing percutaneous coronary intervention (PCI).

METHODS AND RESULTS

This was a Prospective Randomized Open Blinded End-points (PROBE) trial enrolling stable patients with coronary artery disease (CAD) requiring fractional flow reserve-guided PCI of intermediate epicardial coronary lesions. ST-segment elevation at intracoronary electrocardiogram (IC-ECG) during a two-step sequential coronary balloon inflations in the reference vessel during PCI was used as an indirect marker of cardioprotection induced by ischemic preconditioning (IPC). The primary endpoint of the study was the comparison of the delta (Δ) (difference) ST-segment elevation measured by IC-ECG during two-step sequential coronary balloon inflations.

RESULTS

Fifty-three patients were randomized to either clopidogrel or ticagrelor. The study was stopped earlier because the primary endpoint was met at a pre-specified interim analysis. ΔST-segment elevation was significantly higher in ticagrelor as compared to clopidogrel arms (P < 0.0001). Ticagrelor was associated with lower angina score during coronary balloon inflations. There was no difference in coronary microvascular resistance between groups. Adenosine serum concentrations were increased in patients treated with ticagrelor as compared to those treated with clopidogrel.

CONCLUSIONS

Ticagrelor enhances the cardioprotective effects of IPC compared with clopidogrel in stable patients with CAD undergoing PCI. Further studies are warranted to fully elucidate the mechanisms through which ticagrelor may exert cardioprotective effects in humans.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Unique Identifier: NCT02701140.

Ticagrelor, but Not Clopidogrel, Attenuates Hepatic Steatosis in a Model of Metabolic Dysfunction-Associated Steatotic Liver Disease

BACKGROUND

Previous studies have suggested that platelets are associated with inflammation and steatosis and may play an important role in liver health. Therefore, we evaluated whether antiplatelet agents can improve metabolic disorder-related fatty liver disease (MASLD).

METHODS

The mice used in the study were fed a high-fat-diet (HFD) and were stratified through liver biopsy at 18 weeks. A total of 22 mice with NAFLD activity scores (NAS) ≥ 4 were randomly divided into three groups (HFD-only, clopidogrel (CLO; 35 mg/kg/day), ticagrelor (TIC; 40 mg/kg/day) group). And then, they were fed a feed mixed with the respective drug for 15 weeks. Blood and tissue samples were collected and used in the study.

RESULTS

The TIC group showed a significantly lower degree of NAS and steatosis than the HFD group (p = 0.0047), but no effect on the CLO group was observed. Hepatic lipogenesis markers' (SREBP1c, FAS, SCD1, and DGAT2) expression and endoplasmic reticulum (ER) stress markers (CHOP, Xbp1, and GRP78) only reduced significantly in the TIC treatment group. Inflammation genes (MCP1 and TNF-α) also decreased significantly in the TIC group, but not in the CLO group. Nile red staining intensity and hepatic lipogenesis markers were reduced significantly in HepG2 cells following TIC treatment.

CONCLUSION

Ticagrelor attenuated NAS and hepatic steatosis in a MASLD mice model by attenuating lipogenesis and inflammation, but not in the CLO group.

Off-Target Effects of P2Y12 Receptor Inhibitors: Focus on Early Myocardial Fibrosis Modulation

Several studies have demonstrated that, beyond their antithrombotic effects, P2Y12 receptor inhibitors may provide additional off-target effects through different mechanisms. These effects range from the preservation of endothelial barrier function to the modulation of inflammation or stabilization of atherosclerotic plaques, with an impact on different cell types, including endothelial and immune cells. Many P2Y12 inhibitors have been developed, from ticlopidine, the first thienopyridine, to the more potent non-thienopyridine derivatives such as ticagrelor which may promote cardioprotective effects following myocardial infarction (MI) by inhibiting adenosine reuptake through sodium-independent equilibrative nucleoside transporter 1 (ENT1). Adenosine may affect different molecular pathways involved in cardiac fibrosis, such as the Wnt (wingless-type)/beta (β)-catenin signaling. An early pro-fibrotic response of the epicardium and activation of cardiac fibroblasts with the involvement of Wnt1 (wingless-type family member 1)/β-catenin, are critically required for preserving cardiac function after acute ischemic cardiac injury. This review discusses molecular signaling pathways involved in cardiac fibrosis post MI, focusing on the Wnt/β-catenin pathway, and the off-target effect of P2Y12 receptor inhibition. A potential role of ticagrelor was speculated in the early modulation of cardiac fibrosis, thanks to its off-target effect.

Advances in nitric oxide regulators for the treatment of ischemic stroke

Ischemic stroke (IS) is a life-threatening disease worldwide. Nitric oxide (NO) derived from l-arginine catalyzed by NO synthase (NOS) is closely associated with IS. Three isomers of NOS (nNOS, eNOS and iNOS) produce different concentrations of NO, resulting in quite unlike effects during IS. Of them, n/iNOSs generate high levels of NO, detrimental to brain by causing nerve cell apoptosis and/or necrosis, whereas eNOS releases small amounts of NO, beneficial to the brain via increasing cerebral blood flow and improving nerve function. As a result, a large variety of NO regulators (NO donors or n/iNOS inhibitors) have been developed for fighting IS. Regrettably, up to now, no review systematically introduces the progresses in this area. This article first outlines dynamic variation rule of NOS/NO in IS, subsequently highlights advances in NO regulators against IS, and finally presents perspectives based on concentration-, site- and timing-effects of NO production to promote this field forward.

Platelet-Mediated Transfer of Cardioprotection by Remote Ischemic Conditioning and Its Abrogation by Aspirin But Not by Ticagrelor

PURPOSE

The role of platelets during myocardial ischemia/reperfusion (I/R) is ambivalent. They contribute to injury but also to cardioprotection. Repeated blood flow restriction and reperfusion in a tissue/organ remote from the heart (remote ischemic conditioning, RIC) reduce myocardial I/R injury and attenuate platelet activation. Whether or not platelets mediate RIC's cardioprotective signal is currently unclear.

METHODS AND RESULTS

Venous blood from healthy volunteers (without or with pretreatment of 500/1000 mg aspirin or 180 mg ticagrelor orally, 2-3 h before the study, n = 18 each) was collected before and after RIC (3 × 5 min blood pressure cuff inflation at 200 mmHg on the left upper arm/5 min deflation). Washed platelets were isolated. Platelet-poor plasma was used to prepare plasma-dialysates. Platelets (25 × 103/µL) or plasma-dialysates (1:10) prepared before and after RIC from untreated versus aspirin- or ticagrelor-pretreated volunteers, respectively, were infused into isolated buffer-perfused rat hearts. Hearts were subjected to global 30 min/120 min I/R. Infarct size was stained. Infarct size was less with infusion of platelets/plasma-dialysate after RIC (18 ± 7%/23 ± 9% of ventricular mass) than with platelets/plasma-dialysate before RIC (34 ± 7%/33 ± 8%). Aspirin pretreatment abrogated the transfer of RIC's cardioprotection by platelets (after/before RIC, 34 ± 7%/33 ± 7%) but only attenuated that by plasma-dialysate (after/before RIC, 26 ± 8%/32 ± 5%). Ticagrelor pretreatment induced an in vivo formation of cardioprotective factor(s) per se (platelets/plasma-dialysate before RIC, 26 ± 7%/26 ± 7%) but did not impact on RIC's cardioprotection by platelets/plasma-dialysate (20 ± 7%/21 ± 5%).

CONCLUSION

Platelets serve as carriers for RIC's cardioprotective signal through an aspirin-sensitive and thus cyclooxygenase-dependent mechanism. The P2Y12 inhibitor ticagrelor per se induces a humoral cardioprotective signal.

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.

Bioactive surface coating for preventing mechanical heart valve thrombosis

BACKGROUND

Prosthetic heart valves are the only treatment for most patients with severe valvular heart disease. Mechanical valves, made of metallic components, are the most long-lasting type of replacement valves. However, they are prone to thrombosis and require permanent anticoagulation and monitoring, which leads to higher risk of bleeding and impacts the patient's quality of life.

OBJECTIVES

To develop a bioactive coating for mechanical valves with the aim to prevent thrombosis and improve patient outcomes.

METHODS

We used a catechol-based approach to produce a drug-releasing multilayer coating adherent to mechanical valves. The hemodynamic performance of coated Open Pivot valves was verified in a heart model tester, and coating durability in the long term was assessed in a durability tester producing accelerated cardiac cycles. Coating antithrombotic activity was evaluated in vitro with human plasma or whole blood under static and flow conditions and in vivo after surgical valve implantation in a pig's thoracic aorta.

RESULTS

We developed an antithrombotic coating consisting of ticagrelor- and minocycline-releasing cross-linked nanogels covalently linked to polyethylene glycol. We demonstrated the hydrodynamic performance, durability, and hemocompatibility of coated valves. The coating did not increase the contact phase activation of coagulation, and it prevented plasma protein adsorption, platelet adhesion, and thrombus formation. Implantation of coated valves in nonanticoagulated pigs for 1 month efficiently reduced valve thrombosis compared with noncoated valves.

CONCLUSION

Our coating efficiently inhibited mechanical valve thrombosis, which might solve the issues of anticoagulant use in patients and the number of revision surgeries due to valve thrombosis despite anticoagulation.

The effect of ticagrelor on coronary microvascular function after PCI in patients with ACS compared to clopidogrel: A systematic review and meta-analysis

BACKGROUND

The function of coronary microcirculation is an important factor in predicting the prognosis of patients with acute coronary syndrome (ACS) who receive percutaneous coronary intervention (PCI) therapy. Ticagrelor, a type of oral P2Y12 inhibitor, is widely prescribed to ACS patients and can improve prognosis compared to clopidogrel. However, the efficacy of ticagrelor on coronary microcirculation, compared to clopidogrel, remains unclear. The objective of this meta-analysis was to determine the efficacy of ticagrelor on coronary microcirculation.

METHODS

The PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov databases were comprehensively searched to identify studies until November 2022. Data was pooled using the fixed effects model or random effects model based on the level of heterogeneity. Sensitivity analyses were performed to measure the effects of potential confounders.

RESULTS

After screening, 16 trials with a total of 3676 participants were ultimately included in the analysis. The meta-analysis revealed that compared to clopidogrel, patients receiving ticagrelor exhibited a more significant reduction in the IMR (WMD: -6.23, 95% CI: -8.41 to -4.04), a reduction in the cTFC (WMD: -1.88; 95% CI: -3.32 to -0.45), and greater increases in CFR (WMD: 0.38; 95% CI: 0.18 to 0.57), MBG (RR 1.29, 95% CI 1.12 to 1.48), and TIMI (RR 1.03, 95% CI 1.00 to 1.06).

CONCLUSION

Our findings suggest that, compared to clopidogrel, ticagrelor has a significant effect in reducing coronary microcirculatory resistance, enhancing coronary blood flow reserve, and improving myocardial perfusion.

The Plasma Concentration of Ticagrelor and Aspirin as a Predictor of Bleeding Complications in Chinese Acute Coronary Syndrome Patients With Dual Antiplatelet Therapy: A Prospective Observational Study

PURPOSE

This study evaluated the association among the plasma concentration of ticagrelor, ARC124910XX, aspirin, and salicylic acid with the risk of recent bleeding in patients with the acute coronary syndrome. To this end, we developed an accurate model to predict bleeding.

METHODS

A total of 84 patients included in this study cohort between May 2021 and November 2021. The risk factors were identified by univariate and multivariate analyses, and statistically significant risk factors identified in the multivariate analysis were included in the nomogram. We used the calibration curve and the receiver operating characteristic curve to verify the accuracy of the prediction model.

RESULTS

Multivariable logistic analysis showed that ticagrelor concentration (odds ratio [OR]: 2.47, 95% confidence interval [CI], 1.51-4.75, P = 0.002), ST-segment elevation acute myocardial infarction (OR: 32.2, 95% CI, 2.37-780, P = 0.016), and lipid-lowering drugs (OR: 11.52, 95% CI, 1.91-110, P = 0.015) were positively correlated with bleeding. However, angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker (OR: 0.04, 95% CI, 0.004-0.213, P < 0.001) was negatively correlated with bleeding. The receiver operating characteristic curve analysis showed that ticagrelor concentration and these factors together predict the occurrence of bleeding (area under receiver operating characteristic curve = 0.945, 95% CI, 0.896-0.994) and that ticagrelor concentration >694.90 ng/mL is the threshold of bleeding concentration (area under receiver operating characteristic curve = 0.696, 95% CI, 0.558-0.834).

CONCLUSION

In patients with acute coronary syndrome treated with dual antiplatelet therapy, ticagrelor concentration >694.90 ng/mL was an independent risk factor for bleeding (OR: 2.47, 95% CI, 1.51-4.75, P = 0.002), but ARC124910XX and salicylic acid concentration did not affect bleeding risk ( P > 0.05).

The Role of Antiplatelet in the Management of Sickle Cell Disease Patients

Sickle cell disease (SCD) is a genetic disorder characterized by abnormal hemoglobin, leading to red blood cell deformities and subsequent vaso-occlusive events. Platelet activation and adhesion play a significant role in the pathophysiology of SCD, contributing to the development of complications such as vaso-occlusive events, stroke, acute chest syndrome, and other manifestations. Antiplatelet therapy has emerged as a potential strategy to mitigate these complications by modulating the platelet function and reducing thrombotic events. This review article provides an overview of antiplatelet therapy's role in managing SCD patients. It discusses the pathophysiological abnormalities in the platelet function in SCD, the rationale for antiplatelet therapy, and the evidence supporting its use in various clinical scenarios. The article explores aspirin as the primary antiplatelet agent in SCD, including its mechanism of action, dosing considerations, and efficacy and safety data. Additionally, it highlights other antiplatelet agents, such as clopidogrel, prasugrel, ticagrelor, and emerging therapies under investigation. Clinical applications of antiplatelet therapy in primary and secondary prevention and the management of acute chest syndrome and other SCD complications are also discussed. Safety considerations are emphasized, including bleeding risk assessment, monitoring, and patient selection for antiplatelet therapy. Finally, the review highlights future research and clinical practice directions, including the development of novel antiplatelet agents, combination therapies, and the integration of antiplatelet therapy with other SCD treatments. Overall, this review provides a comprehensive understanding of the current role of antiplatelet therapy in SCD management, the challenges faced, and future directions for improving patient outcomes.

Mechanochemical Oxidative Degradation of Thienopyridine Containing Drugs: Toward a Simple Tool for the Prediction of Drug Stability

The long-term stability of an active-pharmaceutical ingredient and its drug products plays an important role in the licensing process of new pharmaceuticals and for the application of the drug at the patient. It is, however, difficult to predict degradation profiles at early stages of the development of new drugs, making the entire process very time-consuming and costly. Forced mechanochemical degradation under controlled conditions can be used to realistically model long-term degradation processes naturally occurring in drug products, avoiding the use of solvents, thus excluding irrelevant solution-based degradation pathways. We present the forced mechanochemical oxidative degradation of three platelet inhibitor drug products, where the drug products contain thienopyridine. Model studies using clopidogrel hydrogen sulfate (CLP) and its drug formulation Plavix show that the controlled addition of excipients does not affect the nature of the main degradants. Experiments using drug products Ticlopidin-neuraxpharm and Efient show that significant degradation occurs after short reaction times of only 15 min. These results highlight the potential of mechanochemistry for the study of degradation processes of small molecules relevant to the prediction of degradation profiles during the development of new drugs. Furthermore, these data provide exciting insights into the role of mechanochemistry for chemical synthesis in general.

Distal Flow Diversion with Anti-Thrombotically Coated and Bare Metal Low-Profile Flow Diverters—A Comparison

Background and purpose: The establishment of low-profile flow diverting stents (FDS), for example, the Silk Vista Baby (SVB) and the p48MW, facilitated endovascular treatment of peripheral cerebral aneurysms. This study therefore aims to compare the performance and outcomes of the SVB with those of the p48MW HPC, with a special focus on hemodynamic aspects of peripheral segments and bifurcations. Materials and methods: The study cohort comprises 108 patients, who were either treated with the SVB or the p48MW HPC between June 2018 and April 2021. Results: Sixty patients received a SVB and forty-eight patients a p48MW HPC. The SVB was used predominantly in the AcomA-complex, and the p48MW HPC in the MCA bifurcation. Immediately after implantation, significant hemodynamic downgrading (OKM A2-A3, B1-B3, C3) was achieved in 60% in the SVB group vs. 75.1% in the p48MW HPC group. At the second follow-up, after an average of 8.8 and 10.9 months, respectively, OKM D1 was observed in 64.4% of the SVB group vs. 27.3% in the p48MW HPC group. Only 1.7% vs. 6.8% of the aneurysms remained morphologically unaltered (OKM A1). Adverse events with persisting neurologic sequalae at last follow-up were largely comparable in both groups (5.0% vs. 4.2%). Conclusion: Immediately after implantation, the p48MW HPC had a more profound hemodynamic impact than the SVB; however, early complete occlusions were achieved in a greater proportion of lesions after implantation of the uncoated SVB.

Periprocedural P2Y12 inhibitors improve perioperative outcomes after carotid stenting by primarily decreasing strokes

OBJECTIVE

The continuation of antiplatelet agents in the periprocedural period around carotid stenting (CAS) procedures is felt to be mandatory to minimize the risk of periprocedural stroke. However, the optimal antiplatelet regimen is unclear, with some advocating dual antiplatelet therapy, and others supporting the use of P2Y₁₂ inhibitors alone. The objective of this study was to evaluate the periprocedural effect of P2Y₁₂ inhibitors for CAS.

METHODS

The Vascular Quality Initiative was used from years 2007 to 2020. All transcarotid artery revascularization (TCAR) and transfemoral carotid artery stenting (TF-CAS) procedures were included. Patients were stratified based on perioperative use of P2Y₁₂ inhibitors as well as symptomatic status. Primary end points were perioperative neurological events (strokes and transient ischemic attacks). Secondary end points were mortality and myocardial infarction.

RESULTS

A total of 31,036 CAS procedures were included for analysis, with 49.8% TCAR and 50.2% TF-CAS cases; 63.8% of patients were male and 82.3% of patients were on a P2Y₁₂ inhibitor. P2Y₁₂ inhibitor use was more common in males, asymptomatic patients, those older than 70 years, and concurrent statin use. P2Y₁₂ inhibitors were more likely to be used in TCAR cases than in TF-CAS cases (87.3% vs 76.8%; P < .001). The rate of periprocedural neurological events in the whole cohort was 2.6%. Patients on P2Y₁₂ inhibitors were significantly less likely to experience a periprocedural neurological event (2.3% vs 3.9%; P < .001) and mortality (0.6% vs 2.1%; P < .001) than those who were not on a P2Y₁₂ inhibitor. There was no effect on the rates of myocardial infarction. On multivariate analysis, both symptomatic and asymptomatic patients on P2Y₁₂ inhibitors were significantly less likely to develop perioperative neurological events. Additionally, the use of P2Y₁₂ inhibitors demonstrated an independent significant effect in reducing of the rate of perioperative stroke (odds ratio, 0.29; 95% confidence interval, 0.25-0.33). Finally, additional analysis of the types of P2Y₁₂ inhibitors used revealed that all seemed to be equally effective in decreasing the periprocedural neurological event rate.

CONCLUSIONS

The use of perioperative P2Y₁₂ inhibitors seems to markedly decrease the perioperative neurological event rate with TCAR and TF-CAS in both symptomatic and asymptomatic patients and should be strongly considered. Patients with contraindications to P2Y₁₂ inhibitors may not be appropriate candidates for any CAS procedure. Additionally, alternative types of P2Y₁₂ inhibitors seem to be equally effective as clopidogrel. Finally, an analysis of the Vascular Quality Initiative demonstrates that, even for TCAR cases, only 87.3% of patients seem to be on P2Y₁₂ inhibitors in the periprocedural period, leaving room for significant improvement.

Endothelial biomarkers and platelet reactivity on ticagrelor versus clopidogrel in patients after acute coronary syndrome with and without concomitant type 2 diabetes: a preliminary observational study

BACKGROUND

Pleiotropic effects have been implicated in clinical benefits of ticagrelor compared to thienopyridine P2Y₁₂ antagonists. There are conflicting data regarding effects of ticagrelor vs. thienopyridine P2Y₁₂ blockers on endothelial function. Our aim was to compare endothelial biomarkers and their relations with platelet reactivity in real-world patients after acute coronary syndrome (ACS) on maintenance dual antiplatelet therapy (DAPT) with ticagrelor or clopidogrel stratified by diabetes status.

METHODS

Biochemical indices of endothelial dysfunction/activation and platelet reactivity by multiple electrode aggregometry were compared in 126 stable post-ACS subjects (mean age: 65 ± 10 years, 92 men and 34 women), including patients with (n = 61) or without (n = 65) coexistent type 2 diabetes (T2DM) on uneventful maintenance DAPT with either ticagrelor (90 mg b.d.) or clopidogrel (75 mg o.d.) in addition to low-dose aspirin. Exclusion criteria included a complicated in-hospital course, symptomatic heart failure, left ventricular ejection fraction < 40% and relevant coexistent diseases except for well-controlled diabetes, mild renal insufficiency or hypertension.

RESULTS

Clinical characteristics were similar in patients on ticagrelor (n = 62) and clopidogrel (n = 64). The adenosine diphosphate-induced platelet aggregation and circulating soluble P-selectin (sP-selectin) were decreased in ticagrelor users irrespective of T2DM status (p < 0.001 and p < 0.01 for platelet reactivity and sP-selectin, respectively). Plasma levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) were lower in T2DM subjects on ticagrelor vs. clopidogrel (758 ± 162 vs. 913 ± 217 µg/L, p < 0.01). In contrast, plasma sVCAM-1 was similar in non-diabetic patients on ticagrelor and clopidogrel (872 ± 203 vs. 821 ± 210 µg/L, p > 0.7). The concentrations of sE-selectin, monocyte chemoattractant protein-1 and asymmetric dimethylarginine did not differ according to the type of P2Y₁₂ antagonist regardless of T2DM status. Platelet reactivity was unrelated to any endothelial biomarker in subjects with or without T2DM.

CONCLUSIONS

Our preliminary findings may suggest an association of ticagrelor-based maintenance DAPT with favorable endothelial effects compared to clopidogrel users in stable post-ACS patients with T2DM. If proven, this could contribute to more pronounced clinical benefits of ticagrelor in diabetic subjects.

Assessment of myocardial salvage in patients with STEMI undergoing thrombolysis: ticagrelor versus clopidogrel

Background

In the setting of ST-segment elevation myocardial infarction (STEMI), the faster and stronger antiplatelet action of ticagrelor compared to clopidogrel, as well as its pleiotropic effects, could result in a greater degree of cardioprotection and final infarct size (FIS) limitation. The aim of our study was to comparatively evaluate the effect of ticagrelor and clopidogrel on myocardial salvage index (MSI) in STEMI patients undergoing thrombolysis.

Methods

Forty-two STEMI patients treated with thrombolysis were randomized to receive clopidogrel (n = 21) or ticagrelor (n = 21), along with aspirin. Myocardial area at risk (AAR) was calculated according to the BARI and the APPROACH jeopardy scores. FIS was quantified by cardiac magnetic resonance imaging (CMR) performed 5–6 months post-randomization. MSI was calculated as (AAR-FIS)/AAR × 100%. Primary endpoint of our study was MSI. Secondary endpoints were FIS and CMR-derived left ventricular ejection fraction (LVEF) at 5 –6 months post-randomization.

Results

By using the BARI score for AAR calculation, mean MSI was 52.25 ± 30.5 for the clopidogrel group and 54.29 ± 31.08 for the ticagrelor group (p = 0.83), while mean MSI using the APPROACH score was calculated at 51.94 ± 30 and 53.09 ± 32.39 (p = 0.9), respectively. Median CMR-derived FIS—as a percentage of LV—was 10.7% ± 8.25 in the clopidogrel group and 12.09% ± 8.72 in the ticagrelor group (p = 0.6). Mean LVEF at 5–6 months post-randomization did not differ significantly between randomization groups.

Conclusions

Our results suggest that the administration of ticagrelor in STEMI patients undergoing thrombolysis offer a similar degree of myocardial salvage, compared to clopidogrel.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02735-1.

In-vivo platelet activation and aggregation during and after acute atherothrombotic myocardial infarction in patients with and without Type-2 diabetes mellitus treated with ticagrelor

INTRODUCTION

Patients with type-2 diabetes are twice as likely to suffer from acute myocardial infarction (AMI) and have a higher incidence of recurrent events than their non-diabetic counterparts. Ticagrelor is a platelet inhibitor known to reduce major adverse cardiovascular events (MACE) in AMI patients. This study measures the level and change in platelet activation and aggregation at the time of and following an AMI in patients with and without diabetes treated with ticagrelor.

MATERIALS/METHODS

P₂Y₁₂ receptor inhibitor naïve patients presenting with AMI were prospectively enrolled. Blood collection occurred before coronary angiography (baseline: T₀), 2, 4, 24, 48 h after baseline, and at a three-month follow-up. Ticagrelor was administered within five minutes of T₀. We assessed platelet activation via measurements of surface P-selectin and platelet activated glycoprotein IIb/IIIa-1 (PAC-1) and assessed platelet aggregation via monocyte, lymphocyte, and granulocyte aggregates. We hypothesize that platelet activation and aggregation will be proportionally impacted to the same degree by ticagrelor, regardless of diabetes status.

RESULTS

Ninety-seven patients were prospectively enrolled (diabetes, N = 33; no diabetes, N = 64). No difference was observed in the expression of P-selectin and PAC-1 at any given point between diabetes and non-diabetes groups (p > 0.05). No difference was observed in the percentage of platelet bound to leukocytes at any measured timepoint between patients with and without diabetes (p > 0.05). Platelet leukocyte aggregation was suppressed during the acute phase compared to quiescence equally among both groups.

DISCUSSION

Ticagrelor demonstrated similar in-vivo effects on platelet activation and aggregation regardless of diabetes status in patients presenting with AMI.

Mesoporous Silica Nanoparticles Carrying MicroRNA-124 to Target P2Y12 Facilitates Cerebral Angiogenesis in Lacunar Cerebral Infarction Through Stem Cell Factor/c-Kit Signaling Pathway

MicroRNA (miRNA)-124 inhibitor may enhance cerebral blood vessel formation in lacunar cerebral infarction (LCI) and mesoporous silica nanoparticles are highlighted as a drug carrier which improves patients' outcome. This study explored the impact of miR-124 and its promising targeted gene P2Y₁₂ encapsulated by mesoporous silica nanoparticles (MSNs) on progression of LCI, and its interaction between SCF/c-kit signaling pathway. After establishment of animal models, the animals were divided into 6 groups, namely: model group, blank group, empty carrier group, carrier + miR-124 inhibitor group, SCF/c-kit inhibitor group, and P2Y₁₂ agonist group. Western blot analysis and microscope determined the expression level of miR-124 in the rat brain tissue slices. MVD, SCF and c-kit P2Y₁₂ protein expression levels were detected and their targeting relationship was verified. miR-124 was poorly expressed in the cells of rats with LCI upon injection of MSNs carrying miR-124-inhibitor. The LCI model group had the highest number of VEGF-positive. Compared with the model group, the number in the carrier + miR-124 inhibitor group was lowest. Moreover, treatment with SCF/c-kit inhibitor and P2Y₁₂ agonist also obtained reduction in the number of VEGF-positive cells with less prominent effect (P < 0.05). With elevation of MVD in the LCI rats, injection of P2Y₁₂ agonist or SCF/c-kit inhibitor significantly decreased the amount of MVD, while miR-124 inhibitor-loaded MSNs better reduced the MVD level. Besides, the LCI rats exhibited up-regulated level of P2Y₁₂ protein. Injection of P2Y₁₂ agonist or SCF/c-kit inhibitor dramatically decreased the level of P2Y₁₂, where the level was still higher than that of carrier + miR-124 inhibitor group. Moreover, administration of miR-124 inhibitor-loaded MSNs resulted in increased SCF and c-kit protein level, and SCF/c-kit inhibitor group and P2Y₁₂ agonist group also had increased SCF and c-kit protein level, compared to the model group. Mechanistically, the miR-124 was indicated to target P2Y₁₂ with stronger fluorescence intensity in mutant plasmid (P < 0.05). MSN-encapsulated miR-124 inhibitor increased the expression of SCF/c-kit protein by targeting P2Y₁₂, thereby enhancing regeneration of cerebral blood vessels in LCI.

Ticagrelor alleviates high-carbohydrate intake induced altered electrical activity of ventricular cardiomyocytes by regulating sarcoplasmic reticulum-mitochondria miscommunication

Metabolic syndrome (MetS) is associated with additional cardiovascular risk in mammalians while there are relationships between hyperglycemia-associated cardiovascular dysfunction and increased platelet P2Y12 receptor activation. Although P2Y12 receptor antagonist ticagrelor (Tica) plays roles in reduction of cardiovascular events, its beneficial mechanism remains poorly understood. Therefore, we aimed to clarify whether Tica can exert a direct protective effect in ventricular cardiomyocytes from high-carbohydrate diet-induced MetS rats, at least, through affecting sarcoplasmic reticulum (SR)-mitochondria (Mit) miscommunication. Tica treatment of MetS rats (150 mg/kg/day for 15 days) significantly reversed the altered parameters of action potentials by reversing sarcolemmal ionic currents carried by voltage-dependent Na+ and K+ channels, and Na+/Ca2+-exchanger in the cells, expressed P2Y12 receptors. The increased basal-cytosolic Ca2+ level and depressed SR Ca2+ load were also reversed in Tica-treated cells, at most, though recoveries in the phosphorylation levels of ryanodine receptors and phospholamban. Moreover, there were marked recoveries in Mit structure and function (including increases in both autophagosomes and fragmentations) together with recoveries in Mit proteins and the factors associated with Ca2+ transfer between SR-Mit. There were further significant recoveries in markers of both ER stress and oxidative stress. Taken into consideration the Tica-induced prevention of ER stress and mitochondrial dysfunction, our data provided an important document on the pleiotropic effects of Tica in the electrical activity of the cardiomyocytes from MetS rats. This protective effect seems through recoveries in SR-Mit miscommunication besides modulation of different sarcolemmal ion-channel activities, independent of P2Y12 receptor antagonism.

Platelet P2Y 12 Receptor Deletion or Pharmacological Inhibition does not Protect Mice from Sepsis or Septic Shock

Introduction  Platelets are increasingly appreciated as key effectors during sepsis, raising the question of the usefulness of antiplatelet drugs to treat patients with sepsis.

Objective  Evaluate the potential contribution of the platelet P2Y ₁₂ receptor in the pathogenesis of polymicrobial-induced sepsis and septic shock in mice.

Methods  The effects of P2Y ₁₂ inhibition using clopidogrel treatment and of platelet-specific deletion of the P2Y ₁₂ receptor in mice were examined in two severity grades of cecal ligation and puncture (CLP) leading to mild sepsis or septic shock.

Results  Twenty hours after induction of the high grade CLP, clopidogrel- and vehicle-treated mice displayed a similar 30% decrease in mean arterial blood pressure (MAP) characteristic of shock. Septic shock-induced thrombocytopenia was not modified by clopidogrel treatment. Plasma concentrations of inflammatory cytokines and myeloperoxidase (MPO) were similarly increased in clopidogrel- and vehicle-treated mice, indicating comparable increase in systemic inflammation. Thrombin-antithrombin (TAT) complexes and the extent of organ damage were also similar. In mild-grade CLP, clopidogrel- and vehicle-treated mice did not display a significant decrease in MAP, while thrombocytopenia and plasma concentrations of TNFα, IL6, IL10, MPO, TAT and organ damage reached similar levels in both groups, although lower than those reached in the high grade CLP. Similarly, mice with platelet-specific deletion of the P2Y ₁₂ receptor were not protected from CLP-induced sepsis or septic shock.

Conclusion  The platelet P2Y ₁₂ receptor does not contribute to the pathogenesis of sepsis or septic shock in mice, suggesting that P2Y ₁₂ receptor antagonists may not be beneficial in patients with sepsis or septic shock.

The role of P2Y12 receptor inhibition in ischemic stroke on microglia, platelets and vascular smooth muscle cells

P2Y12 receptors on platelets have long been the main target of antiplatelet drugs. However, a growing number of studies have revealed that P2Y12 receptor activation on microglia and vascular smooth muscle cells (VSMCs) also aggravates ischemic stroke injury. The proliferation and migration of VSMCs in the vascular wall have important influence on the early lesion of atherosclerosis, which may lead to the origin of cerebral ischemic attack of atherosclerosis. Blockage of cellular P2Y12 receptors could inhibit microglial activation, block formation of platelet-leukocyte aggregates, reduce proinflammatory cytokine levels and suppress migration and proliferation of VSMCs, implying that apart from anti-thrombotic effect, P2Y12 inhibitors have additional neuroprotective, anti-inflammatory and anti-atherosclerotic therapeutic benefits against ischemic stroke. In this review, we will summarize recent advances in studies on P2Y12 receptors and emphatically introduce their significance in microglia, platelets and VSMCs after ischemic stroke, discussing how to exert the beneficial effects of P2Y12 inhibition.

Involvement of P2Y12 receptors in an NTG-induced model of migraine in male mice

BACKGROUND AND PURPOSE

P2Y₁₂ receptors (P2Y₁₂ Rs) are known to regulate different forms of pain and inflammation. In this study we investigated the participation of P2Y₁₂ Rs in an animal model of migraine.

EXPERIMENTAL APPROACH

We tested the effect of the centrally administered selective P2Y₁₂ R antagonist PSB-0739, and P2Y₁₂ R gene deficiency in acute nitroglycerin (NTG)-treated mice. Additionally, platelet depletion was used to investigate the role of platelet P2Y₁₂ Rs during migraine-like pain.

KEY RESULTS

NTG induced sensory hypersensitivity of C57BL/6 wild-type (P2ry12^+/+ ) mice, accompanied by an increase in c-fos and CGRP expression in the upper cervical spinal cord (C1-C2) and trigeminal nucleus caudalis (TNC). Similar changes were also observed in P2Y₁₂ R gene-deficient (P2ry12^-/- ) mice. Prophylactic intrathecal application of PSB-0739 reversed thermal hyperalgesia and head grooming time in wild-type mice but had no effect in P2ry12^-/- mice; furthermore, it was also effective when applied as a post-treatment. PSB-0739 administration suppressed the expression of c-fos in C1-C2 and TNC, and decrease C1-C2 levels of dopamine and serotonin in wild-type mice. NTG treatment itself did not change adenosine diphosphate (ADP)-induced platelet activation measured by CD62P upregulation in wild-type mice. Platelet depletion by anti-mouse CD41 antibody and clopidogrel attenuated NTG-induced thermal hypersensitivity and head grooming time in mice.

CONCLUSION AND IMPLICATIONS

Taken together, our findings show that acute inhibition of P2Y₁₂ Rs alleviates migraine-like pain in mice, by modulating the expression of c-fos, and platelet P2Y₁₂ Rs might contribute to this effect. Hence, it is suggested that the blockade of P2Y₁₂ Rs may have therapeutic potential against migraine.

Electrical impedance vs. light transmission aggregometry: Testing platelet reactivity to antiplatelet drugs using the MICELI POC impedance aggregometer as compared to a commercial predecessor

BACKGROUND

Patients' responses to antiplatelet therapy significantly vary, with individuals showing high residual platelet reactivity associated with thrombosis. To personalize thrombosis management, platelet function testing has been suggested as a promising tool able to monitor the antithrombotic effect of antiplatelet agents in real-time. We have prototyped the MICELI, a miniature and easy-to-use electrical impedance aggregometer (EIA), measuring platelet aggregation in whole blood. Here, we tested the capability of the MICELI aggregometer to quantify platelet reactivity on antiplatelet agents, as compared with conventional light-transmission aggregometry (LTA).

METHODS

Platelet aggregation in ACD-anticoagulated whole blood and platelet-rich plasma of healthy donors (n = 30) was evaluated. The effect of clopidogrel, ticagrelor, cangrelor, cilostazol, and tirofiban on ADP-induced aggregation was tested, while aspirin was evaluated with arachidonic acid and collagen. Platelet aggregation was recorded using the MICELI or BioData PAP-8E (Bio/Data Corp.) aggregometers.

RESULTS

The MICELI aggregometer detected an adequate and comparable dose-dependent decrease of platelet aggregation in response to increments of drugs' concentrations, as compared to LTA (the inter-device R2 = 0.79-0.93). Platelet aggregation in platelet-rich plasma recorded by LTA showed higher sensitivity to antiplatelet agents, but it couldn't distinguish between different drug doses as indicated by saturation of the aggregatory response.

CONCLUSION

Platelet aggregation in whole blood as recorded by EIA represents a better model system for evaluation of platelet reactivity as compared with platelet aggregation in platelet-rich plasma as recorded by LTA, since EIA takes into consideration the modulatory effect of other blood cells on platelet hemostatic function and pharmacodynamics of antiplatelet drugs in vivo. As such, the MICELI impedance aggregometer could be potentially employed for the point-of-care monitoring of platelet function in patients on-treatment for personalized tailoring of their antiplatelet regimen.

Cangrelor ameliorates CLP-induced pulmonary injury in sepsis by inhibiting GPR17

BACKGROUND

Sepsis is a common complication of severe wound injury and infection, with a very high mortality rate. The P2Y12 receptor inhibitor, cangrelor, is an antagonist anti-platelet drug.

METHODS

In our study, we investigated the protective mechanisms of cangrelor in CLP-induced pulmonary injury in sepsis, using C57BL/6 mouse models.

RESULTS

TdT-mediated dUTP Nick-End Labeling (TUNEL) and Masson staining showed that apoptosis and fibrosis in lungs were alleviated by cangrelor treatment. Cangrelor significantly promoted surface expression of CD40L on platelets and inhibited CLP-induced neutrophils in Bronchoalveolar lavage fluid (BALF) (p < 0.001). We also found that cangrelor decreased the inflammatory response in the CLP mouse model and inhibited the expression of inflammatory cytokines, IL-1β (p  < 0.01), IL-6 (p < 0.05), and TNF-α (p < 0.001). Western blotting and RT-PCR showed that cangrelor inhibited the increased levels of G-protein-coupled receptor 17 (GPR17) induced by CLP (p < 0.001).

CONCLUSION

Our study indicated that cangrelor repressed the levels of GPR17, followed by a decrease in the inflammatory response and a rise of neutrophils in BALF, potentially reversing CLP-mediated pulmonary injury during sepsis.

Hyperinflammation and airway surface liquid dehydration in cystic fibrosis: purinergic system as therapeutic target

OBJECTIVE AND DESIGN

The exacerbate inflammatory response contributes to the progressive loss of lung function in cystic fibrosis (CF), a genetic disease that affects the osmotic balance of mucus and mucociliary clearance, resulting in a microenvironment that favors infection and inflammation. The purinergic system, an extracellular signaling pathway characterized by nucleotides, enzymes and receptors, may have a protective role in the disease, through its action in airway surface liquid (ASL) and anti-inflammatory response.

MATERIALS AND METHODS

To make up this review, studies covering topics of CF, inflammation, ASL and purinergic system were selected from the main medical databases, such as Pubmed and ScienceDirect.

CONCLUSION

We propose several ways to modulate the purinergic system as a potential therapy for CF, like inhibition of P2X7, activation of P2Y2, A2A and A2B receptors and blocking of adenosine deaminase. Among them, we postulate that the most suitable strategy is to block the action of adenosine deaminase, which culminates in the increase of Ado levels that presents anti-inflammatory actions and improves mucociliary clearance. Furthermore, it is possible to maintain the physiological levels of ATP to control the hydration of ASL. These therapies could correct the main mechanisms that contribute to the progression of CF.

Influence of Antiplatelet Agents on the Lipid Composition of Platelet Plasma Membrane: A Lipidomics Approach with Ticagrelor and Its Active Metabolite

Lipids contained in the plasma membrane of platelets play an important role in platelet function. Modifications in the lipid composition can fluidify or rigidify the environment around embedded receptors, in order to facilitate the access of the receptor by the drug. However, data concerning the lipid composition of platelet plasma membrane need to be updated. In addition, data on the impact of drugs on plasma membrane composition, in particular antiplatelet agents, remain sparse. After isolation of platelet plasma membrane, we assessed, using lipidomics, the effect of ticagrelor, a P2Y12 antagonist, and its active metabolite on the lipid composition of these plasma membranes. We describe the exact lipid composition of plasma membrane, including all sub-species. Ticagrelor and its active metabolite significantly increased cholesterol and phosphatidylcholine ether with short saturated acyl chains 16:0/16:0, and decreased phosphatidylcholine, suggesting overall rigidification of the membrane. Furthermore, ticagrelor and its active metabolite decreased some arachidonylated plasmalogens, suggesting a decrease in availability of arachidonic acid from the membrane phospholipids for synthesis of biologically active mediators. To conclude, ticagrelor and its active metabolite seem to influence the lipid environment of receptors embedded in the lipid bilayer and modify the behavior of the plasma membrane.

Performance of Plasma Adenosine as a Biomarker for Predicting Cardiovascular Risk

Adenosine boasts promising preclinical and clinical data supporting a vital role in modulating vascular homeostasis. Its widespread use as a diagnostic and therapeutic agent have been limited by its short half-life and complex biology, though adenosine-modulators have shown promise in improving vascular healing. Moreover, circulating adenosine has shown promise in predicting cardiovascular (CV) events. We sought to delineate whether circulating plasma adenosine levels predict CV events in patients undergoing invasive assessment for coronary artery disease. Patients undergoing invasive angiography had clinical data prospectively recorded in the Cardiovascular and Percutaneous ClInical TriALs (CAPITAL) revascularization registry and blood samples collected in the CAPITAL Biobank from which adenosine levels were quantified. Tertile-based analysis was used to assess prediction of major adverse cardiovascular events (MACE; composite of death, myocardial infarction, unplanned revascularization, and cerebrovascular accident). Secondary analyses included MACE subgroups, clinical subgroups and adenosine levels. There were 1,815 patients undergoing angiography who had blood collected with adenosine quantified in 1,323. Of those quantified, 51.0% were revascularized and 7.3% experienced MACE in 12 months of follow-up. Tertile-based analysis failed to demonstrate any stratification of MACE rates (log rank, P = 0.83), when comparing low-to-middle (hazard ratio (HR) 1.10, 95% confidence interval (CI) 0.68-1.78, P = 0.70) or low-to-high adenosine tertiles (HR 0.95, 95% CI 0.56-1.57, P = 0.84). In adjusted analysis, adenosine similarly failed to predict MACE. Finally, adenosine did not predict outcomes in patients with acute coronary syndrome nor in those revascularized or treated medically. Plasma adenosine levels do not predict subsequent CV outcomes or aid in patient risk stratification.

Pre- and Post-Conditioning of the Heart: An Overview of Cardioprotective Signaling Pathways

Since the discovery of ischemic pre- and post-conditioning, more than 30 years ago, the knowledge about the mechanisms and signaling pathways involved in these processes has significantly increased. In clinical practice, on the other hand, such advancement has yet to be seen. This article provides an overview of ischemic pre-, post-, remote, and pharmacological conditioning related to the heart. In addition, we reviewed the cardioprotective signaling pathways and therapeutic agents involved in the above-mentioned processes, aiming to provide a comprehensive evaluation of the advancements in the field. The advancements made over the last decades cannot be ignored and with the exponential growth in techniques and applications. The future of pre- and post-conditioning is promising.

Inflammation and thrombosis in COVID-19 pathophysiology: proteinase-activated and purinergic receptors as drivers and candidate therapeutic targets

Evolving information has identified disease mechanisms and dysregulation of host biology that might be targeted therapeutically in coronavirus disease 2019 (COVID-19). Thrombosis and coagulopathy, associated with pulmonary injury and inflammation, are emerging clinical features of COVID-19. We present a framework for mechanisms of thrombosis in COVID-19 that initially derive from interaction of SARS-CoV-2 with ACE2, resulting in dysregulation of angiotensin signaling and subsequent inflammation and tissue injury. These responses result in increased signaling by thrombin (proteinase-activated) and purinergic receptors, which promote platelet activation and exert pathological effects on other cell types (e.g., endothelial cells, epithelial cells, and fibroblasts), further enhancing inflammation and injury. Inhibitors of thrombin and purinergic receptors may, thus, have therapeutic effects by blunting platelet-mediated thromboinflammation and dysfunction in other cell types. Such inhibitors include agents (e.g., anti-platelet drugs) approved for other indications, and that could be repurposed to treat, and potentially improve the outcome of, COVID-19 patients. COVID-19, caused by the SARS-CoV-2 virus, drives dysregulation of angiotensin signaling, which, in turn, increases thrombin-mediated and purinergic-mediated activation of platelets and increase in inflammation. This thromboinflammation impacts the lungs and can also have systemic effects. Inhibitors of receptors that drive platelet activation or inhibitors of the coagulation cascade provide opportunities to treat COVID-19 thromboinflammation.

A geranylated chalcone with antiplatelet activity from the leaves of breadfruit (Artocarpus altilis)

Platelet plays a crucial role in cardiovascular diseases (CVDs) development. Abnormalities in platelet aggregation provokes thromboembolism, eventually leading to death. In Indonesia, breadfruit (Artocarpus altilis) leaf is traditionally used to treat CVDs. This study aimed to evaluate the antiplatelet activity of A. altilis leaf extract (AAE) and to identify its active compound. A. altilis leaves were extracted with ethanol, and the antiplatelet activity was assessed using ADP-induced platelet aggregation. The major compound was isolated with column chromatography followed by preparative TLC, and the structure was determined on the basis of UV, MS, IR, and NMR spectra. The binding mode of the active compound to platelet receptors was characterized in in silico study. AAE exhibited an antiplatelet activity (IC50 of 252.23 µg/mL). A geranylated chalcone, 2-geranyl-2ʹ,3,3,4ʹ-tetrahydroxydihydrochalcone (GTDC) was identified as the antiplatelet compound (IC50 of 9.09 µM). GTDC actions with P2Y12 platelet receptor involving three amino acid residues.

An evaluation of ticagrelor for the treatment of sickle cell anemia

INTRODUCTION

Ticagrelor is an antiplatelet agent approved for the treatment of patients with an acute coronary syndrome or a history of myocardial infarction. Considering the evidence demonstrating that ticagrelor-mediated inhibition of platelet activation and aggregation have beneficial effects in the treatment of thrombotic conditions, clinical studies have been conducted to evaluate the use of this drug for the treatment of sickle cell disease (SCD), demonstrating satisfactory tolerability and safety.

AREAS COVERED

Clinical investigation has characterized the pharmacokinetic and pharmacodynamical profile, as well as the efficacy and safety of ticagrelor to prevent painful vaso-occlusive crisis (painful episodes and acute chest syndrome) in SCD patients.

EXPERT OPINION

While phase 1 and 2 clinical trials demonstrated satisfactory tolerability and safety, the conclusion of phase 3 clinical trials is crucial to prove the efficacy of ticagrelor as a therapeutic option for the treatment of SCD. Thus, it is expected that ticagrelor, especially in combination with other drugs, will improve the clinical profile and quality of life of patients with SCD.

Identification of patients at higher risk for myocardial injury following elective coronary artery intervention

OBJECTIVES

To evaluate myocardial injury and infarction (MI) following elective percutaneous coronary intervention (PCI).

BACKGROUND

The substantially higher analytical power of high-sensitivity troponin (hsTn) assays allows detection of minor cardiac troponin (cTn) levels, which may be useful in monitoring myocardial injury and guiding therapies.

METHODS

Serial hsTnT measurements were conducted in patients undergoing elective PCI and were related to the extent of coronary artery disease (CAD) as reflected by the SYNTAX score risk categories and American College of Cardiology/American Heart Association classification of coronary lesions. Myocardial injury and MI were diagnosed according to the second and third versions of universal MI definition.

RESULTS

The study population consisted of 530 patients, who were grouped into low (41.3%), intermediate (35.4%), and high (23.3%) SYNTAX risk categories. The treated coronary lesions were classified into A 7.8%, B1 24.1%, B2 21.1%, C1 24.6%, and C2 22.4%. Postprocedural hsTnT increases correlated significantly with the complexity of treated coronary lesions (p < .05) and CAD magnitude (p < .05). Rates of MI type 4a according to the second and third MI definition criteria were 98 (27.5%) and 15 (4.2%) cases in patients with normal baseline hsTnT values (N = 357, 67.4%), as well as 137 (79.2%) and 27 (15.6%) cases in those with elevated baseline hsTnT values (N = 173, 32.6%), respectively.

CONCLUSIONS

After elective PCI, cTn releases correlate significantly with lesion complexity and CAD extent. Use of hsTnT assay enables precise monitoring of PCI-related myocardial injury and may identify patients at higher risk for ischemic events, who may benefit from potent platelet inhibition, which needs to be investigated in randomized trials.

Ticagrelor Conditioning Effects Are Not Additive to Cardioprotection Induced by Direct NLRP3 Inflammasome Inhibition: Role of RISK, NLRP3, and Redox Cascades

Inhibition of either P2Y12 receptor or the nucleotide-binding oligomerization domain- (NOD-) like receptor pyrin domain containing 3 (NLRP3) inflammasome provides cardioprotective effects. Here, we investigate whether direct NLRP3 inflammasome inhibition exerts additive effects on myocardial protection induced by the P2Y12 receptor antagonist Ticagrelor. Ticagrelor (150 mg/kg) was orally administered to rats for three consecutive days. Then, isolated hearts underwent an ischemia/reperfusion (30 min ischemia/60 min reperfusion; IR) protocol. The selective NLRP3 inflammasome inhibitor INF (50 μM) was infused before the IR protocol to the hearts from untreated animals or pretreated with Ticagrelor. In parallel experiments, the hearts isolated from untreated animals were perfused with Ticagrelor (3.70 μM) before ischemia and subjected to IR. The hearts of animals pretreated with Ticagrelor showed a significantly reduced infarct size (IS, 49 ± 3% of area at risk, AAR) when compared to control IR group (69 ± 2% of AAR). Similarly, ex vivo administration of INF before the IR injury resulted in significant IS reduction (38 ± 3% of AAR). Myocardial IR induced the NLRP3 inflammasome complex formation, which was attenuated by either INF pretreatment ex vivo, or by repeated oral treatment with Ticagrelor. The beneficial effects induced by either treatment were associated with the protective Reperfusion Injury Salvage Kinase (RISK) pathway activation and redox defence upregulation. In contrast, no protective effects nor NLRP3/RISK modulation were recorded when Ticagrelor was administered before ischemia in isolated heart, indicating that Ticagrelor direct target is not in the myocardium. Our results confirm that Ticagrelor conditioning effects are likely mediated through platelets, but are not additives to the ones achieved by directly inhibiting NLRP3.

Platelet Functions During Extracorporeal Membrane Oxygenation. Platelet-Leukocyte Aggregates Analyzed by Flow Cytometry as a Promising Tool to Monitor Platelet Activation

Extracorporeal membrane oxygenation (ECMO) is an extracorporeal circulation used to manage patients with severe circulatory or respiratory failure. It is associated with both high bleeding and thrombosis risks, mainly as a result of biomaterial/blood interface phenomena, high shear stress, and complex inflammatory response involving the activation of coagulation and complement systems, endothelial cells, leukocytes, and platelets. Besides their critical role in hemostasis, platelets are important players in inflammatory reactions, especially due to their ability to bind and activate leukocytes. Hence, we reviewed studies on platelet function of ECMO patients. Moreover, we addressed the issue of platelet–leukocyte aggregates (PLAs), which is a key step in both platelet and leukocyte activation, and deserves to be investigated in these patients. A reduced expression of GPIb and GPVI was found under ECMO therapy, due to the shedding processes. However, defective platelet aggregation is inconsistently reported and is still not clearly defined. Due to the high susceptibility of PLAs to pre-analytical conditions, defining and strictly adhering to a rigorous laboratory methodology is essential for reliable and reproducible results, especially in the setting of complex inflammatory situations like ECMO. We provide results on sample preparation and flow cytometric whole blood evaluation of circulating PLAs.

Sulfonic Acid Derivative-Modified SBA-15, PHTS and MCM-41 Mesoporous Silicas as Carriers for a New Antiplatelet Drug: Ticagrelor Adsorption and Release Studies

Three mesoporous, siliceous materials, i.e., SBA-15 (Santa Barbara Amorphous), PHTS (Plugged Hexagonal Templated Silica) and MCM-41 (Mobil Composition of Matter), functionalized with a sulfonic acid derivative, were successfully prepared and applied as the carriers for the poorly water-soluble drug, ticagrelor. The siliceous carriers were characterized using nitrogen sorption analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM) and elemental analysis. The adsorption studies were conducted in acetonitrile. At the highest equilibrium concentrations, the amount of ticagrelor Q_e that adsorbed onto the examined silicas was in the range of 83 to 220 mg/g, increasing in the following order: PHTS-(CH₂)₃-SO₃H < SBA-15-(CH₂)₃-SO₃H < MCM-41-(CH₂)₃-SO₃H. The equilibrium adsorption data were analyzed using the Freundlich, Jovanovich, Langmuir, Temkin, Dubinin-Radushkevich, Dubinin-Astakhov and Redlich-Peterson models. In order to find the best-fit isotherm for each model, a nonlinear fitting analysis was carried out. Based on the minimized values of the ARE function, the fit of the isotherms to the experimental points for ticagrelor adsorption onto the modified silicas can be ordered as follows: SBA-15-(CH₂)₃-SO₃H (Redlich-Peterson > Dubinin-Astakhov > Temkin), PHTS-(CH₂)₃-SO₃H (Redlich-Peterson > Temkin > Dubinin-Astakhov), MCM-41-(CH₂)₃-SO₃H (Redlich-Peterson > Dubinin-Astakhov > Langmuir). The values of adsorption energy (above 8 kJ/mol) indicate the chemical nature of ticagrelor adsorption onto propyl-sulfonic acid-modified silicas. The results of release studies indicated that at pH 4.5, modified SBA-15 and MCM-41 carriers accelerate the drug dissolution process, compared to the dissolution rate of free crystalline ticagrelor. Intriguingly, modified PHTS silica provides prolonged drug release kinetics compared to other siliceous adsorbents and to the dissolution rate of crystalline ticagrelor. A Weibull release model was employed to describe the release profiles of ticagrelor from the prepared carriers. The time necessary to dissolve 50% and 90% of ticagrelor from mesoporous adsorbents at pH 4.5 increased in the following order: SBA-15-(CH₂)₃-SO₃H < MCM-41-(CH₂)₃-SO₃H < PHTS-(CH₂)₃-SO₃H.

Ticagrelor Prevents Endothelial Cell Apoptosis through the Adenosine Signalling Pathway in the Early Stages of Hypoxia

BACKGROUND

Several studies have reported the beneficial effects of anti-platelet drugs in cardioprotection against ischaemia-reperfusion injuries. To date, no studies have focused on the indirect cytoprotective effects of ticagrelor via adenosine receptor on the endothelium.

METHOD

By evaluating cell viability and cleaved caspase 3 expression, we validated a model of endothelial cell apoptosis induced by hypoxia. In hypoxic endothelial cells treated with ticagrelor, we quantified the extracellular concentration of adenosine, and then we studied the involvement of adenosine pathways in the cytoprotective effect of ticagrelor.

RESULTS

Our results showed that 10 µM ticagrelor induced an anti-apoptotic effect in our model associated with an increase of extracellular adenosine concentration. Similar experiments were conducted with cangrelor but did not demonstrate an anti-apoptotic effect. We also found that A2B and A3 adenosine receptors were involved in the anti-apoptotic effect of ticagrelor in endothelial cells exposed to 2 h of hypoxia stress.

CONCLUSION

we described an endothelial cytoprotective mechanism of ticagrelor against hypoxia stress, independent of blood elements. We highlighted a mechanism triggered mainly by the increased extracellular bioavailability of adenosine, which activates A2B and A3 receptors on the endothelium.

Ticagrelor reverses the mitochondrial dysfunction through preventing accumulated autophagosomes-dependent apoptosis and ER stress in insulin-resistant H9c2 myocytes

Ticagrelor, a P₂Y₁₂-receptor inhibitor, and a non-thienopyridine agent are used to treat diabetic patients via its effects on off-target mechanisms. However, the exact sub-cellular mechanisms by which ticagrelor exerts those effects remains to be elucidated. Accordingly, the present study aimed to examine whether ticagrelor influences directly the cardiomyocytes function under insulin resistance through affecting mitochondria-sarco(endo)plasmic reticulum (SER) cross-talk. Therefore, we analyzed the function and ultrastructure of mitochondria and SER in insulin resistance-mimicked (50-μM palmitic acid for 24-h) H9c2 cardiomyocytes in the presence or absence of ticagrelor (1-µM for 24-h). We found that ticagrelor treatment significantly prevented depolarization of mitochondrial membrane potential and increases in reactive oxygen species with a marked increase in the ATP level in insulin-resistant H9c2 cells. Ticagrelor treatment also reversed the increases in the resting level of free Ca²⁺ and mRNA level of P₂Y₁₂ receptors as well as preserved ER stress and apoptosis in insulin-resistant H9c2 cells. Furthermore, we determined marked repression with ticagrelor treatment in the increased number of autophagosomes and degeneration of mitochondrion, including swelling and loss of crista besides recoveries in enlargement and irregularity seen in SER in insulin-resistant H9c2 cells. Moreover, ticagrelor treatment could prevent the altered mRNA levels of Becklin-1 and type 1 equilibrative nucleoside transporter (ENT1), which are parallel to the preservation of ultrastructural ones. Our overall data demonstrated that ticagrelor can directly affect cardiomyocytes and provide marked protection against ER stress and dramatic induction of autophagosomes, and therefore, can alleviate the ER stress-induced oxidative stress increase and cell apoptosis during insulin resistance.

Ticagrelor Increases SIRT1 and HES1 mRNA Levels in Peripheral Blood Cells from Patients with Stable Coronary Artery Disease and Chronic Obstructive Pulmonary Disease

Ticagrelor is a powerful P2Y₁₂ inhibitor with pleiotropic effects in the cardiovascular system. Consistently, we have reported that in patients with stable coronary artery disease (CAD) and concomitant chronic obstructive pulmonary disease (COPD) who underwent percutaneous coronary intervention (PCI), 1-month treatment with ticagrelor was superior in improving biological markers of endothelial function, compared with clopidogrel. The objective of this study was to investigate the mechanisms underlying these beneficial effects of ticagrelor by conducting molecular analyses of RNA isolated from peripheral blood cells of these patients. We determined mRNAs levels of markers of inflammation and oxidative stress, such as RORγt (T helper 17 cells marker), FoxP3 (regulatory T cells marker), NLRP3, ICAM1, SIRT1, Notch ligands JAG1 and DLL4, and HES1, a Notch target gene. We found that 1-month treatment with ticagrelor, but not clopidogrel, led to increased levels of SIRT1 and HES1 mRNAs. In patients treated with ticagrelor or clopidogrel, we observed a negative correlation among changes in both SIRT1 and HES1 mRNA and serum levels of Epidermal Growth Factor (EGF), a marker of endothelial dysfunction found to be reduced by ticagrelor treatment in our previous study. In conclusion, we report that in stable CAD/COPD patients ticagrelor positively regulates HES1 and SIRT1, two genes playing a protective role in the context of inflammation and oxidative stress. Our observations confirm and expand previous studies showing that the beneficial effects of ticagrelor in stable CAD/COPD patients may be, at least in part, mediated by its capacity to reduce systemic inflammation and oxidative stress.

Cardioprotective properties of the platelet P2Y12 receptor inhibitor prasugrel on cardiac ischemia/reperfusion injury

OBJECTIVE

The effects of prasugrel, a third-generation thienopyridine, on myocardial infarction, and ischemia-induced ventricular arrhythmias was evaluated in open-chest anesthetized rats. The role of protein kinase C and phosphoinositide 3-kinase pathways in these effects was also examined.

METHODS

The effect of P2Y₁₂ receptor inhibition by prasugrel (3-10 mg/kg, po) on infarct size after 30-min coronary artery occlusion and 120-min reperfusion or on arrhythmias after 7-min coronary occlusion and 7-min reperfusion was evaluated.

RESULTS

In the control group, 31.25 ± 3.01% of the risk zone infarcted. At both prasugrel doses, infarct size was significantly smaller than that in the control group: 5.03 ± 0.81% for 3 mg/kg (p < 0.0001), and 8.78 ± 2.04% for 10 mg/kg (p < 0.0001). The protein kinase C antagonist chelerythrine abolished the anti-infarct effect of prasugrel at 24.77 ± 1.73% as did the phosphoinositide 3-kinase antagonist wortmannin abolished the anti-infarct effect of prasugrel at 27.45 ± 2.74%. Ten mg/kg prasugrel reduced the duration of VT (p = 0.0152 vs control), and wortmannin, but not chelerythrine, reversed the effect of prasugrel on arrhythmias (p = 0.0295).

CONCLUSION

The selective P2Y₁₂ inhibitor prasugrel provides effective protection against myocardial infarction and ischemia-induced ventricular arrhythmias in rats. As in ischemic postconditioning, protein kinase C and phosphoinositide 3-kinase signaling pathways play a role in this protection.

Antithrombotic Therapy: Prevention and Treatment of Atherosclerosis and Atherothrombosis

Atherosclerosis is a multifactorial vascular disease that develops in the course of a lifetime. Numerous risk factors for atherosclerosis have been identified, mostly inflicting pro-inflammatory effects. Vessel injury, such as occurring during erosion or rupture of atherosclerotic lesions triggers blood coagulation, in attempt to maintain hemostasis (protect against bleeding). However, thrombo-inflammatory mechanisms may drive blood coagulation such that thrombosis develops, the key process underlying myocardial infarction and ischemic stroke (not due to embolization from the heart). In the blood coagulation system, platelets and coagulation proteins are both essential elements. Hyperreactivity of blood coagulation aggravates atherosclerosis in preclinical models. Pharmacologic inhibition of blood coagulation, either with platelet inhibitors, or better documented with anticoagulants, or both, limits the risk of thrombosis and may potentially reverse atherosclerosis burden, although the latter evidence is still based on animal experimentation.Patients at risk of atherothrombotic complications should receive a single antiplatelet agent (acetylsalicylic acid, ASA, or clopidogrel); those who survived an atherothrombotic event will be prescribed temporary dual antiplatelet therapy (ASA plus a P2Y12 inhibitor) in case of myocardial infarction (6-12 months), or stroke (<6 weeks), followed by a single antiplatelet agent indefinitely. High risk for thrombosis patients (such as those with peripheral artery disease) benefit from a combination of an anticoagulant and ASA. The price of gained efficacy is always increased risk of (major) bleeding; while tailoring therapy to individual needs may limit the risks to some extent, new generations of agents that target less critical elements of hemostasis and coagulation mechanisms are needed to maintain efficacy while reducing bleeding risks.

Platelet-Derived Extracellular Vesicles as Target of Antiplatelet Agents. What Is the Evidence?

Platelet-derived large extracellular vesicles (often referred to as microparticles in the field of cardiovascular disease) have been identified as effector in the atherothrombotic process, therefore representing a target of pharmacological intervention of potential interest. Despite that, limited evidence is so far available concerning the effects of antiplatelet agents on the release of platelet-derived extracellular vesicles. In the present narrative review, the mechanisms leading to vesiculation in platelets and the pathophysiological processes implicated will be discussed. This will be followed by a summary of the present evidence concerning the effects of antiplatelet agents under experimental conditions and in clinical settings.

Ticagrelor induces paraoxonase-1 (PON1) and better protects hypercholesterolemic mice against atherosclerosis compared to clopidogrel

Ticagrelor (TIC), a P2Y purinoceptor 12 (P2Y₁₂)-receptor antagonist, has been widely used to treat patients with acute coronary syndrome. Although animal studies suggest that TIC protects against atherosclerosis, it remains unknown whether it does so through its potent platelet inhibition or through other pathways. Here, we placed hypercholesterolemic Ldlr^-/-Apobec1^-/- mice on a high-fat diet and treated them with either 25 mg/kg/day of clopidogrel (CLO) or 180 mg/kg/day of TIC for 16 weeks and evaluated the extent of atherosclerosis. Both treatments equally inhibited platelets as determined by ex vivo platelet aggregation assays. The extent of atherosclerosis, however, was significantly less in the TIC group than in the CLO group. Immunohistochemical staining and ELISA showed that TIC treatment was associated with less macrophage infiltration to the atherosclerotic intima and lower serum levels of CCL4, CXCL10, and TNFα, respectively, than CLO treatment. Treatment with TIC, but not CLO, was associated with higher serum activity and tissue level of paraoxonase-1 (PON1), an anti-atherosclerotic molecule, suggesting that TIC might exert greater anti-atherosclerotic activity, compared with CLO, through its unique ability to induce PON1. Although further studies are needed, TIC may prove to be a viable strategy in the prevention and treatment of chronic stable human atherosclerosis.

Effect of Ticagrelor Versus Clopidogrel on Aortic Stiffness in Patients With Coronary Artery Disease

Background

We compared the acute and midterm effect of ticagrelor versus clopidogrel on aortic stiffness.

Methods and Results

We studied 117 patients in a randomized, assessor‐blinded, parallel‐group trial. The acute effect of ticagrelor was studied in 58 patients randomized (1:1) to receive a loading dose of clopidogrel (600 mg) or ticagrelor (180 mg). Carotid‐femoral pulse wave velocity (cfPWV) was measured before, 3, and 24 hours after the loading dose. The midterm effect (30‐day treatment period) was studied in 59 subjects who underwent percutaneous coronary intervention and were randomized to either clopidogrel (75 mg, OD) or ticagrelor (90 mg BID). cfPWV was measured before and at 30 days of treatment. Circulating markers of inflammation and endothelial function were measured at all study points. Repeated‐measures analysis showed a significant main effect for treatment (P=0.03), with the ticagrelor showing a reduction in cfPWV after treatment. cfPWV at 24 hours was significantly lower in the ticagrelor group compared with the clopidogrel group (P=0.017) (maximal response reduction by 0.42±0.26 m/s). At 30 days, cfPWV decreased in the ticagrelor group, whereas there was no change with clopidogrel (−0.43±0.57 versus 0.12±0.14 m/s, P=0.004). There were no significant changes in both the acute and midterm study period in the pro‐inflammatory and endothelial function parameters.

Conclusions

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02071212. Ticagrelor decreases cfPWV for 24 hours after the loading dose and at 1 month post–percutaneous coronary intervention compared with clopidogrel. Considering that aortic stiffness is an independent predictor of cardiovascular events, this finding may have clinical implications regarding the beneficial effect of ticagrelor.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02071212.

Circulating blood cells and extracellular vesicles in acute cardioprotection

During an ST-elevation myocardial infarction (STEMI), the myocardium undergoes a prolonged period of ischaemia. Reperfusion therapy is essential to minimize cardiac injury but can paradoxically cause further damage. Experimental procedures to limit ischaemia and reperfusion (IR) injury have tended to focus on the cardiomyocytes since they are crucial for cardiac function. However, there is increasing evidence that non-cardiomyocyte resident cells in the heart (as discussed in a separate review in this Spotlight series) as well as circulating cells and factors play important roles in this pathology. For example, erythrocytes, in addition to their main oxygen-ferrying role, can protect the heart from IR injury via the export of nitric oxide bioactivity. Platelets are well-known to be involved in haemostasis and thrombosis, but beyond these roles, they secrete numerous factors including sphingosine-1 phosphate (S1P), platelet activating factor, and cytokines that can all strongly influence the development of IR injury. This is particularly relevant given that most STEMI patients receive at least one type of platelet inhibitor. Moreover, there are large numbers of circulating vesicles in the blood, including microvesicles and exosomes, which can exert both beneficial and detrimental effects on IR injury. Some of these effects are mediated by the transfer of microRNA (miRNA) to the heart. Synthetic miRNA molecules may offer an alternative approach to limiting the response to IR injury. We discuss these and other circulating factors, focussing on potential therapeutic targets relevant to IR injury. Given the prevalence of comorbidities such as diabetes in the target patient population, their influence will also be discussed. This article is part of a Cardiovascular Research Spotlight Issue entitled 'Cardioprotection Beyond the Cardiomyocyte', and emerged as part of the discussions of the European Union (EU)-CARDIOPROTECTION Cooperation in Science and Technology (COST) Action, CA16225.

Development Strategy and Relative Bioavailability of a Pediatric Tablet Formulation of Ticagrelor

BACKGROUND AND OBJECTIVE

Ticagrelor is a P2Y₁₂ receptor inhibitor approved as an antiplatelet drug for patients with acute coronary syndrome or a history of myocardial infarction. Ticagrelor is also being investigated for the reduction of vaso-occlusive crises in pediatric patients with sickle cell disease. A pediatric formulation suitable for this age range was developed; the development strategy is described. Primary objectives were determining the relative bioavailability of ticagrelor pediatric tablets and granules for oral suspension to the adult immediate-release tablet, and the pediatric tablets taken whole and dispersed/suspended in water to the granules for oral suspension. Bioequivalence between the pediatric tablet taken whole or suspended in water was also assessed. Secondary objectives were comparing the formulations' safety and tolerability.

METHODS

We conducted a randomized, four-period, cross-over, single-dose study. Pharmacokinetic parameters were assessed for ticagrelor and its active metabolite AR-C124910XX. Bioequivalence was concluded if the 90% confidence intervals of the maximum plasma concentration and area under the plasma concentration-time curve ratios were contained completely within the 80.00-125.00% limits for ticagrelor/AR-C124910XX.

RESULTS

Forty-four healthy adults (95% white; 57% male) were included. Similar bioavailability of ticagrelor (and AR-C124910XX) was demonstrated for all comparisons tested. Ticagrelor pediatric tablets taken whole were bioequivalent to pediatric tablets suspended in water. The plasma concentration-time profiles for ticagrelor and AR-C124910XX were similar, showing rapid ticagrelor absorption and AR-C124910XX formation. All formulations were well tolerated.

CONCLUSION

Similar bioavailability of a new pediatric dispersible tablet formulation of ticagrelor for use across a wide age range of pediatric patients was demonstrated compared with other oral ticagrelor formulations. CLINICALTRIALS.

GOV IDENTIFIER

NCT03126695.

EUDRACT

2017-000371-93.