Ticagrelor - toward more efficient platelet inhibition and beyond

Comparison of Heart Rates in Patients Initiated on Ticagrelor Versus Other P2Y12 Inhibitors After an Inferior ST Elevation Myocardial Infarction (STEMI)

BACKGROUND

P2Y12 inhibitors have differing associations of bradyarrhythmias. Ticagrelor has been shown to increase adenosine plasma concentrations leading to increases in bradyarrhythmias. While clopidogrel and prasugrel have not been shown to have any association with bradyarrhythmias.

OBJECTIVE

The objective of this study was to determine heart rates after ticagrelor initiation compared to clopidogrel/prasugrel in inferior ST Elevation Myocardial Infarction (STEMI) patients.

METHODS

This was a retrospective, multicenter study conducted at 3 primary percutaneous coronary intervention (PCI) centers between January 1, 2017 and September 30, 2022. Adult patients were included if they were diagnosed with an inferior STEMI to the right coronary artery (RCA) and treated with PCI followed by an oral P2Y12 inhibitor. The primary outcome was heart rate at 48 hours or discharge, whichever first, after administration of ticagrelor compared to clopidogrel/prasugrel.

RESULTS

This study reviewed 331 patients, 172 in the ticagrelor group and 159 in the clopidogrel/prasugrel group. There were no statistical differences between groups regarding the primary outcome, with a median heart rate of 76 beats per minute (bpm) [67-85] in the ticagrelor group versus 73 bpm [66-84] in the clopidogrel/prasugrel group (P = 0.238). No differences were observed between groups regarding any secondary outcomes.

CONCLUSION AND RELEVANCE

There were similar heart rates between ticagrelor and clopidogrel/prasugrel. There were also similarities in the ability to tolerate beta-blocker therapy after initiation of a P2Y12 inhibitor. The results of this study suggest that in inferior STEMIs when using ticagrelor as the P2Y12 inhibitor, there are not increased clinical manifestations of bradycardia.

Preparation and Evaluation of a Self-Emulsifying Drug Delivery System for Improving the Solubility and Permeability of Ticagrelor

Ticagrelor (TCG) is a BCS class IV antiplatelet drug used to prevent platelet aggregation in patients with acute coronary syndrome, having poor solubility and permeability. The goal of this study was to develop a self-nanoemulsifying drug delivery system (SNEDDS) of TCG to improve its solubility and permeability. The excipients were selected based on the maximum solubility of TCG and observed by UV spectrophotometer. Different combinations of oil, surfactant, and co-surfactant (1:1, 2:1, and 3:1) were used to prepare TCG-SNEDDS formulations, and pseudo-ternary phase diagrams were plotted. The nanoemulsion region was observed. Clove oil (10-20%), Tween-80 (45-70%), and PEG-400 (20-45%) were used as an oil, surfactant, and co-surfactant, respectively. The selected formulations (F1, F2, F3, F4, F5, and F6) were analyzed for ζ potential, polydispersity index (PDI), ζ size, self-emulsification test, cloud point determination, thermodynamic studies, entrapment efficiency, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), in vitro dissolution, ex vivo permeation, and pharmacodynamic study. The TCG-SNEDDS formulations exhibited ζ potential from -9.92 to -6.23 mV, a ζ average of 11.85-260.4 nm, and good PDI. The in vitro drug release in phosphate buffer pH 6.8 from selected TCG-SNEDDS F4 was about 98.45%, and F6 was about 97.86%, displaying improved dissolution of TCG in 0.1 N HCl and phosphate buffer pH 6.8, in comparison to 28.05% of pure TCG suspension after 12 h. While the in vitro drug release in 0.1 N HCl from F4 was about 62.03%, F6 was about 73.57%, which is higher than 10.35% of the pure TCG suspension. In ex vivo permeability studies, F4 also exhibited an improved apparent permeability of 2.7 × 10-6versus 0.6708 × 10-6 cm2/s of pure drug suspension. The pharmacodynamic study in rabbits demonstrated enhanced antiplatelet activity from TCG-SNEDDS F4 compared to that from pure TCG suspension. These outcomes imply that the TCG-SNEDDS may serve as an effective means of enhancing TCG's antiplatelet activity by improving the solubility and permeability of TCG.

Progress in the clinical effects and adverse reactions of ticagrelor

BACKGROUND

Ticagrelor is a novel receptor antagonist that selectively binds to the P2Y12 receptor, thereby inhibiting adenosine diphosphate (ADP)-mediated platelet aggregation. Compared to clopidogrel, ticagrelor has the advantages of a fast onset, potent effects, and a reversible platelet inhibition function, which make this drug clinically suitable for treating acute coronary syndrome (ACS), especially acute ST-segment elevation myocardial infarction (STEMI).

OBJECTIVE

This review was performed to determine the basic characteristics, clinical effects, and adverse reactions of ticagrelor.

METHODS

Relevant trials and reports were obtained from the MEDLINE, Embase, and Cochrane Library databases.

RESULTS

Ticagrelor is rapidly absorbed by the body after oral administration, exhibits inherent activity without requiring metabolic activation, and binds reversibly to the P2Y12 receptor. Ticagrelor has been recommended in ACS treatment guidelines worldwide due to its advantageous pharmacological properties and significant clinical benefits. Ticagrelor inhibits platelet aggregation, inhibits inflammatory response, enhances adenosine function, and has cardioprotective effects. However, ticagrelor also causes adverse reactions such as bleeding tendency, dyspnea, ventricular pause, gout, kidney damage, and thrombotic thrombocytopenic purpura in clinical treatment. Therefore, it is necessary to pay attention to risk assessments when using ticagrelor.

CONCLUSION

Ticagrelor is a promising drug for the effective treatment of ACS. When using ticagrelor, individualized treatment should be provided based on the specific conditions of the patients to avoid serious adverse events.

Management of giant internal carotid aneurysm by extracranial-intracranial bypass and flow diverter stent

Flow diverter stents have become the standard approach to managing intracranial aneurysms; however, in some cases of complex, wide-necked aneurysms, poor outcomes due to stent occlusion have been reported. We report the case of a giant internal carotid artery aneurysm treated by high-flow extracranial-intracranial (EC-IC) bypass with flow diverter deployment. Seven months post-operatively, radiographic imaging demonstrated occlusion of the stent and parent artery, with further ischemic events prevented by collateral flow from the high flow bypass. This case demonstrates the continued utility of EC-IC bypass in the endovascular era, especially as a rescue tool in cases of delayed stent occlusion.

Bioequivalence assessment of two Ticagrelor formulations under fasting condition in healthy Pakistani subjects

Objective

To investigate the Bioequivalence of Anplag® 90mg (Ticagrelor) tablet and Brilinta® 90 mg (Ticagrelor) tablet under fasting conditions in healthy Pakistani subjects.

Method

This was an open-label, cross-over, randomized, single-dose, two-period, single-center Bioequivalence Study conducted at Center of Bioequivalence Studies and Clinical Research (CBSCR), ICCBS, University of Karachi, Karachi, Pakistan from September 2020 to January 2021. This was an open-label, randomized, single-dose, two-period, cross-over Bioequivalence Study. After randomization, a single dose of Ticagrelor 90mg tablet (test or reference drug) were administered orally in 1:1 ratio to each subject under fasting conditions. Seven days washout period was kept between the two periods in order to avoid carry over. Blood samples were then taken up to 48th hours post-dose. Point estimates and 90% confidence intervals (CI) for the ratio of the log-transformed values were calculated. Bioequivalence assessment of both, the reference and the test drugs were based on the primary Pharmacokinetic PK metrics including peak maximum concentration (Cmax), area under the curve (AUC) from zero to last quantifiable concentration (AUClast), and AUC from zero to infinity (AUCtotal) after log-transformation of data with ANOVA. In this bioequivalence study, the primary pharmacokinetic parameters were assessed for both Ticagrelor and its Active Metabolite (AR-C124910XX). Safety endpoints were evaluated by monitoring adverse events (AEs).

Results

The 90% Confidence Intervals (CIs) of the Geometric Mean Ratio for primary PK parameters including Cmax, AUClast, and AUCtotal all were within the accepted bioequivalence range of 80%- 125%. In the current study, no serious adverse events were reported.

Conclusion

Our results showed that the two tested formulations of Ticagrelor tablets were bioequivalent and well tolerated.Trial Registration: ClinicalTrials.gov Identifier: NCT04941196.

Antiplatelet drugs: Potential therapeutic options for the management of neurodegenerative diseases

The blood platelet plays an important role but often remains under-recognized in several vascular complications and associated diseases. Surprisingly, platelet hyperactivity and hyperaggregability have often been considered the critical risk factors for developing vascular dysfunctions in several neurodegenerative diseases (NDDs) like Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. In addition, platelet structural and functional impairments promote prothrombotic and proinflammatory environment that can aggravate the progression of several NDDs. These findings provide the rationale for using antiplatelet agents not only to prevent morbidity but also to reduce mortality caused by NDDs. Therefore, we thoroughly review the evidence supporting the potential pleiotropic effects of several novel classes of synthetic antiplatelet drugs, that is, cyclooxygenase inhibitors, adenosine diphosphate receptor antagonists, protease-activated receptor blockers, and glycoprotein IIb/IIIa receptor inhibitors in NDDs. Apart from this, the review also emphasizes the recent developments of selected natural antiplatelet phytochemicals belonging to key classes of plant-based bioactive compounds, including polyphenols, alkaloids, terpenoids, and flavonoids as potential therapeutic candidates in NDDs. We believe that the broad analysis of contemporary strategies and specific approaches for plausible therapeutic treatment for NDDs presented in this review could be helpful for further successful research in this area.

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.

Comparing the effectiveness and safety of dual antiplatelet with ticagrelor or clopidogrel in elderly Asian patients with acute myocardial infraction

Background

Current guidelines recommend potent P2Y12 inhibitors for patients after acute coronary syndrome. However, the data on the efficacy and safety of potent P2Y12 inhibitors in elderly Asian populations was limited. We aimed to investigate the major adverse cardiovascular events (MACE), bleeding events, and net adverse clinical events (NACE) with ticagrelor and clopidogrel in Taiwanese patients aged 65 and older after acute myocardial infarction (AMI).

Methods

This retrospective population-based cohort study was conducted using data from the National Health Insurance Research Database. The AMI patients aged ≥65 years who underwent percutaneous coronary intervention (PCI) and survived after 1 month were included. The patients were separated into 2 cohorts depending on the type of dual antiplatelet therapy (DAPT) they received: ticagrelor plus aspirin (T + A) or clopidogrel plus aspirin (C + A). We used inverse probability of treatment weighting to balance the difference between these 2 study groups. The outcome included all-cause mortality, MACE (cardiovascular death, nonfatal ischemic stroke, and nonfatal myocardial infarction), intracerebral hemorrhage, major bleeding, and NACE which is composed of cardiovascular death, ischemic and hemorrhagic events. The follow-up period was up to 12 months.

Results

From 2013 to 2017, a total of 14,715 patients who met the eligibility criteria were separated into 2 groups: 5,051 for T + A and 9,664 for C + A. Compared to patients with C + A, patients who received T + A had a lower risk of cardiovascular death and all-cause death, with an adjusted HR of 0.57 [95% confidence interval (CI), 0.38–0.85, p = 0.006] and 0.58 (95% CI 0.45–0.74, p < 0.001), respectively. No differences were found in MACE, intracranial and major bleeding between the 2 groups. In addition, the patients with T + A had a lower risk of NACE with an adjusted HR of 0.86 (95% CI 0.74–1.00, p = 0.045)

Conclusion

Among elderly AMI patients receiving DAPT after successful PCI, ticagrelor was a more favorable P2Y12 inhibitor than clopidogrel because of lowering the risk of death and NACE without increasing the risk of severe bleeding. Ticagrelor is an effective and safe P2Y12 inhibitor in Asian elderly survivors after PCI.

Mitochondrial Effects of Common Cardiovascular Medications: The Good, the Bad and the Mixed

Mitochondria are central organelles in the homeostasis of the cardiovascular system via the integration of several physiological processes, such as ATP generation via oxidative phosphorylation, synthesis/exchange of metabolites, calcium sequestration, reactive oxygen species (ROS) production/buffering and control of cellular survival/death. Mitochondrial impairment has been widely recognized as a central pathomechanism of almost all cardiovascular diseases, rendering these organelles important therapeutic targets. Mitochondrial dysfunction has been reported to occur in the setting of drug-induced toxicity in several tissues and organs, including the heart. Members of the drug classes currently used in the therapeutics of cardiovascular pathologies have been reported to both support and undermine mitochondrial function. For the latter case, mitochondrial toxicity is the consequence of drug interference (direct or off-target effects) with mitochondrial respiration/energy conversion, DNA replication, ROS production and detoxification, cell death signaling and mitochondrial dynamics. The present narrative review aims to summarize the beneficial and deleterious mitochondrial effects of common cardiovascular medications as described in various experimental models and identify those for which evidence for both types of effects is available in the literature.

Pleiotropic Effects of Ticagrelor: Influence on CYP4F2 Gene and Protein Expression in HUVEC and HepG2, and Escherichia coli Bacterial Survival

Background

Antiplatelet drugs, such as ticagrelor, which target platelet P2Y₁₂ receptors, are used for prevention of ischemic heart disease. Ticagrelor is also known to have pleiotropic effects of unknown mechanisms. Ticagrelor could influence the expression of molecules involved in resolution of inflammation. This study aimed to investigate if ticagrelor could change the expression of CYP4F2 and its encoded protein concentration and, additionally, to determine ticagrelor possible antibacterial activity against gram-negative bacteria.

Methods

CYP4F2 expression was determined in HUVEC and HepG2 cell lines by qPCR. CYP4F2 protein concentration was determined by ELISA. Antibiotic susceptibility testing was performed using a disc diffusion method.

Results

Ticagrelor was observed to reduce the expression of CYP4F2 in HUVEC and HepG2 cell lines. It also reduced CYP4F2 protein levels in HUVEC cells. Ticagrelor had no bactericidal activity against gram-negative third generation cephalosporin resistant E. coli.

Conclusion

Ticagrelor reduced CYP4F2 protein concentration in HUVEC, and CYP4F2 expression in HUVEC and HepG2 cells, but had no effect on third-generation cephalosporin-resistant E. coli strains.

Why Not Dipyridamole: a Review of Current Guidelines and Re-evaluation of Utility in the Modern Era

Dipyridamole is an old anti-platelet and coronary vasodilator agent that inhibits platelet phosphodiesterase and increases interstitial adenosine levels. Its use in coronary artery disease (CAD) has fallen out of practice in the modern era with the advent of new anti-platelet agents, and most modern guidelines on the management of CAD either neglect to comment on its utility or outright recommend against it. The majority of the studies used in these guidelines are outdated and took place in an era when high doses of aspirin were used and statins were not widely utilized. There is growing evidence in rat models of dipyridamole's synergy with statins through adenosine modulation resulting in significant myocardial protection against ischemia-reperfusion injury and limitation of infract size. The data in human studies are limited but show a similar potential synergy between dipyridamole and statins. It would thus be prudent to reconsider the recommendations against the use of dipyridamole in CAD and to re-evaluate its possible role and potential benefits through well-designed randomized trials combining it with statins, low-dose aspirin, and/or other anti-platelet agents.

Antiplatelet drugs and liver fibrosis

Liver fibrosis results from an imbalance between extracellular matrix formation and degradation. The background of liver fibrosis is chronic inflammation and subsequent microcirculation disturbance including microthrombosis. Platelets actively participate in liver fibrosis not only as a part of the clotting system but also by releasing granules containing important mediators. In fact, platelets may play a dual role in the pathophysiology of liver fibrosis as they are able to stimulate regeneration as well as aggravate the destruction of the liver. Recent studies revealed that antiplatelet therapy correlates with inhibition of liver fibrosis. However, liver impairment is associated with extensive coagulation disorders thus the safety of antiplatelet therapy is an area for detailed exploration. In this review, the role of platelets in liver fibrosis and accompanying hemostatic disorders are discussed. Additionally, results of animal and human studies on antiplatelet drugs in liver disorders and their potential therapeutic utility are presented.

Cardiovascular Pharmacogenomics: An Update on Clinical Studies of Antithrombotic Drugs in Brazilian Patients

Anticoagulant and antiplatelet drugs effectively prevent thrombotic events in patients with cardiovascular diseases, ischemic stroke, peripheral vascular diseases, and other thromboembolic diseases. However, genetic and non-genetic factors affect the response to antithrombotic therapy and can increase the risk of adverse events. This narrative review discusses pharmacogenomic studies on antithrombotic drugs commonly prescribed in Brazil. Multiple Brazilian studies assessed the impact of pharmacokinetic (PK) and pharmacodynamic (PD) gene variants on warfarin response. The reduced function alleles CYP2C9*2 and CYP2C9*3, and VKORC1 rs9923231 (c.-1639G>A) are associated with increased sensitivity to warfarin and a low dose requirement to prevent bleeding episodes, whereas CYP4F2 rs2108622 (p.Val433Met) carriers have higher dose requirements (warfarin resistance). These deleterious variants and non-genetic factors (age, gender, body weight, co-administered drugs, food interactions, and others) account for up to 63% of the warfarin dose variability. Few pharmacogenomics studies have explored antiplatelet drugs in Brazilian cohorts, finding associations between CYP2C19*2, PON1 rs662 and ABCC3 rs757421 genotypes and platelet responsiveness or clopidogrel PK in subjects with coronary artery disease (CAD) or acute coronary syndrome (ACS), whereas ITGB3 contributes to aspirin PK but not platelet responsiveness in diabetic patients. Brazilian guidelines on anticoagulants and antiplatelets recommend the use of a platelet aggregation test or genotyping only in selected cases of ACS subjects without ST-segment elevation taking clopidogrel, and also suggest CYP2C9 and VKORC1 genotyping before starting warfarin therapy to assess the risk of bleeding episodes or warfarin resistance.

A review of the effects of ticagrelor on adenosine concentration and its clinical significance

BACKGROUND

Ticagrelor is an oral antiplatelet drug that can reversibly bind to the platelet P2Y12 receptor. Ticagrelor is metabolized mainly by CYP3A4 and produces a rapid blood concentration-dependent platelet inhibitory effect. Unlike other P2Y12 receptor antagonists, many clinical features of ticagrelor are not related to P2Y12 receptor antagonism.

PURPOSE

This review aims to gather existing literature on the clinical effects of ticagrelor after inhibiting adenosine uptake.

METHODOLOGY

The current study reviewed literature related to the effects of ticagrelor on adenosine metabolism. The review also examined the drug's biological effects and clinical characteristics to see how it could be used in a clinical setting.

RESULTS

Many studies have shown that ticagrelor can inhibit equilibrative nucleoside transporter 1 (ENT1). This inhibition leads to intracellular adenosine uptake, increased adenosine half-life and plasma concentration levels and an enhanced adenosine-mediated biological effect.

CONCLUSIONS

Based on the studies reviewed, it was found that ticagrelor essentially inhibits adenosine absorption of adenosine into cells through ENT1, which increases the concentration in the blood and subsequently increases the protection of the heart muscle by adenosine. It also prevents platelet aggregation, and extends the biological effects of coronary arteries. Moreover, it leads to a lower mortality rate in acute coronary syndrome (ACS) patients.

Membrane Environment Modulates Ligand-Binding Propensity of P2Y12 Receptor

The binding of natural ligands and synthetic drugs to the P2Y12 receptor is of great interest because of its crucial role in platelets activation and the therapy of arterial thrombosis. Up to now, all computational studies of P2Y12 concentrated on the available crystal structures, while the role of intrinsic protein dynamics and the membrane environment in the functioning of P2Y12 was not clear. In this work, we performed all-atom molecular dynamics simulations of the full-length P2Y₁₂ receptor in three different membrane environments and in two possible conformations derived from available crystal structures. The binding of ticagrelor, its two major metabolites, adenosine diphosphate (ADP) and 2-Methylthioadenosine diphosphate (2MeS-ADP) as agonist, and ethyl 6-[4-(benzylsulfonylcarbamoyl)piperidin-1-yl]-5-cyano-2-methylpyridine-3-carboxylate (AZD1283)as antagonist were assessed systematically by means of ensemble docking. It is shown that the binding of all ligands becomes systematically stronger with the increase of the membrane rigidity. Binding of all ligands to the agonist-bound-like conformations is systematically stronger in comparison to antagonist-bound-likes ones. This is dramatically opposite to the results obtained for static crystal structures. Our results show that accounting for internal protein dynamics, strongly modulated by its lipid environment, is crucial for correct assessment of the ligand binding to P2Y12.

Pharmacokinetics, Bioequivalence and Safety Evaluation of Two Ticagrelor Tablets Under Fasting and Fed Conditions in Healthy Chinese Subjects

Purpose

To evaluate the pharmacokinetics (PK), bioequivalence and safety profiles of test drug and reference drug of 90 mg ticagrelor tablets and their main active metabolite AR-C124910XX under fasting and fed conditions.

Methods

This was a randomized, open-label, single-dose, two-period, two-sequence, and two-treatment crossover study. Subjects were randomized and evenly administered with a single dose of test drug or reference drug of 90 mg ticagrelor tablets orally under fasting or fed conditions with a 7-day washout period. The primary PK parameters were calculated with non-compartmental model, including peak concentration (C_max), area under the curve (AUC) from zero to last quantifiable concentration (AUC_0-t), and AUC from zero to infinity (AUC_0-∞). Bioequivalence was judged by whether the 90% confidence intervals (CIs) of the geometric mean ratio (GMR) of the test/reference drugs were within the predefined range of 80-125%. Adverse events (AEs) were assessed as safety endpoints.

Results

Eighty healthy Chinese subjects (fasting condition: n=40; fed condition: n=40) were enrolled, but two withdrew for personal reasons. As for PK parameters, there was no statistical difference (P>0.05) between the test and reference drugs under both conditions. As for bioequivalence, the 90% CIs of GMR for C_max, AUC_0-t and AUC_0-∞ all fell within 80%-125% regardless of food intake or not. No severe adverse events were observed in the study. Chinese clinical trial registration number is ChiCTR1800015091 (http://www.chictr.org.cn).

Conclusion

Our results demonstrated that the test drug and the reference drug of ticagrelor tablets were bioequivalent. The PK and safety profiles were also similar regardless of food intake or not in healthy Chinese subjects.

Plasma Trimethylamine-N-Oxide Is an Independent Predictor of Long-Term Cardiovascular Mortality in Patients Undergoing Percutaneous Coronary Intervention for Acute Coronary Syndrome

To investigate the association of liver metabolite trimethylamine N-oxide (TMAO) with cardiovascular disease (CV)-related and all-cause mortality in patients with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention. Our prospective observational study enrolled 292 patients with ACS. Plasma concentrations of TMAO were measured during the hospitalization for ACS. Observation period lasted seven yr in median. Adjusted Cox-regression analysis was used for prediction of mortality. ROC curve analysis revealed that increasing concentrations of TMAO levels assessed at the time point of ACS significantly predicted the risk of CV mortality (c-index=0.78, p < 0.001). The cut-off value of >4 μmol/L, labeled as high TMAO level (23% of study population), provided the greatest sum of sensitivity (85%) and specificity (80%) for the prediction of CV mortality and was associated with a positive predictive value of 16% and a negative predictive value of 99%. A multivariate Cox regression model revealed that high TMAO level was a strong and independent predictor of CV death (HR = 11.62, 95% CI: 2.26-59.67; p = 0.003). High TMAO levels as compared with low TMAO levels were associated with the highest risk of CV death in a subpopulation of patients with diabetes mellitus (27.3 vs. 2.6%; p = 0.004). Although increasing TMAO levels were also significantly associated with all-cause mortality, their estimates for diagnostic accuracy were low. High TMAO level is a strong and independent predictor of long-term CV mortality among patients presenting with ACS.

Synthesis of ticagrelor analogues belonging to 1,2,3-triazolo[4,5-d]pyrimidines and study of their antiplatelet and antibacterial activity

Based on the recent observation that the antiplatelet agent ticagrelor and one of its metabolite exert bactericidal activity against gram-positive bacteria, a series of 1,2,3-triazolo[4,5-d]pyrimidines structurally related to ticagrelor were synthesized and examined as putative antiplatelet and antibacterial agents. The aim was to assess the possibility of dissociating the two biological properties and to find novel 1,2,3-triazolo[4,5-d]pyrimidines expressing antiplatelet activity and devoid of in vitro antibacterial activity. The new compounds synthesized were known metabolites of ticagrelor as well as structurally simplified analogues. Some of them were found to express antiplatelet activity and to lose the antibacterial activity, supporting the view that the two activities were not necessarily linked.

Ticagrelor and prasugrel are independent predictors of improved long-term survival in ACS patients

AIM

To investigate the long-term clinical benefit of dual antiplatelet therapy with potent P2Y12 inhibitors compared to clopidogrel in patients with acute coronary syndrome (ACS).

METHODS

In this prospective multicenter observational study, we enrolled 708 patients with ACS treated with clopidogrel (n = 137), ticagrelor (n = 260) or prasugrel (n = 311). Major adverse cardiac events (MACE; over 1 year) and long-term mortality (median: 5.6 years; interquartile range [IQR] 4.9-6.5 years) were assessed. Multiple electrode aggregometry (MEA) was used to measure adenosine diphosphate (ADP)- and arachidonic acid (AA)-induced platelet aggregation.

RESULTS

Type of P2Y12 inhibitor emerged as an independent predictor of long-term mortality and MACE: patients treated with potent platelet inhibitors prasugrel or ticagrelor were at lower risk for long-term mortality (adjusted hazard ratio [HR] = 0.44; 95% CI: 0.22-0.92; P = .028) or MACE (adjusted HR = 0.38; 95% CI: 0.20-0.73; P = .004) than those treated with clopidogrel independent from clinical risk factors. In contrast, the efficacy of clopidogrel decreased with increasing severity of ACS: platelet aggregation was 37% higher in patients with ST segment elevation myocardial infarction (STEMI) and 25% higher in patients with non-ST elevation myocardial infarction (non-STEMI) compared to patients with unstable angina (P = .039). Patients with diabetes achieved less potent ADP- and AA-induced platelet inhibition under clopidogrel, compared to patients without diabetes (P = .045; P = .030, respectively).

CONCLUSION

In the setting of ACS, treatment with ticagrelor or prasugrel reduced long-term mortality and 1-year MACE as compared to clopidogrel.

Bleeding complications after dual antiplatelet therapy with ticagrelor versus dual antiplatelet therapy with clopidogrel-a propensity-matched comparative study of two antiplatelet regimes in off-pump coronary artery bypass grafting

Purpose

Ticagrelor combined with aspirin had shown better saphenous vein graft patency than aspirin with clopidogrel after off-pump coronary artery bypass grafting. However, the safety of this drug in regard to bleeding complications remains unknown. The aim of our study was to assess the bleeding complications of dual antiplatelet therapy with aspirin and ticagrelor compared with aspirin and clopidogrel within the first 3 months after off-pump surgery.

Methods

Three hundred eighty-two consecutive patients who were prescribed aspirin with ticagrelor (ticagrelor group) were compared with 660 patients who received aspirin and clopidogrel (clopidogrel group). After propensity matching, 144 patients in each group were compared for bleeding events and major adverse cardiac and cerebral events. Major bleeding was defined as composite outcome of re-exploration for bleeding, any fatal bleeding, intracranial bleeding, and any bleeding requiring hospitalization.

Results

Patients in the ticagrelor group had more incidence of re-exploration for bleeding (p = 0.042), pericardial effusion requiring drainage (p = 0.007), readmissions (p < 0.01), gastrointestinal bleeding (p = 0.01), and major bleeding (5.8% vs. 2.1%, p < 0.01, OR 2.8 (1.43-5.58)). After propensity analysis, gastrointestinal bleed (p = 0.024), major bleeding (7.6% vs.1.4%, p < 0.001, OR 5.8 (1.28-26.97)), length of ICU stay (p = 0.039), and readmissions (p = 0.003, OR 11.83 (1.51-92.86)) were more in the ticagrelor group. Major adverse cardiac and cerebral events were similar between the groups.

Conclusion

Dual antiplatelet therapy with aspirin and ticagrelor increased gastrointestinal bleeding events, major bleeding events, and readmission rates compared with aspirin and clopidogrel after off-pump coronary artery bypass grafting.

Endothelial cells, neutrophils and platelets: getting to the bottom of an inflammatory triangle

Severe fibrotic and thrombotic events permeate the healthcare system, causing suffering for millions of patients with inflammatory disorders. As late-state consequences of chronic inflammation, fibrosis and thrombosis are the culmination of pathological interactions of activated endothelium, neutrophils and platelets after vessel injury. Coupling of these three cell types ensures a pro-coagulant, cytokine-rich environment that promotes the capture, activation and proliferation of circulating immune cells and recruitment of key pro-fibrotic cell types such as myofibroblasts. As the first responders to sterile inflammatory injury, it is important to understand how endothelial cells, neutrophils and platelets help create this environment. There has been a growing interest in this intersection over the past decade that has helped shape the development of therapeutics to target these processes. Here, we review recent insights into how neutrophils, platelets and endothelial cells guide the development of pathological vessel repair that can also result in underlying tissue fibrosis. We further discuss recent efforts that have been made to translate this knowledge into therapeutics and provide perspective as to how a compound or combination therapeutics may be most efficacious when tackling fibrosis and thrombosis that is brought upon by chronic inflammation.

Role of P2Y Receptors in Platelet Extracellular Vesicle Release

Platelet extracellular vesicles (PEVs) are potential new biomarkers of platelet activation which may allow us to predict and/or diagnose developing coronary thrombosis before myocardial necrosis occurs. The P2Y1 and P2Y12 receptors play a key role in platelet activation and aggregation. Whereas the P2Y1 antagonists are at the preclinical stage, at present, the P2Y12 antagonists are the most effective treatment strategy to prevent stent thrombosis after percutaneous coronary intervention. Despite an increasing number of publications on PEVs, the mechanisms underlying their formation, including the role of purinergic receptors in this process, remain an active research field. Here, we outline the clinical relevance of PEVs in cardiovascular disease, summarize the role and downstream signalling of P2Y receptors in platelet activation, and discuss the available evidence regarding their role in PEV formation.

Drug-eluting Vein Graft with Acetylsalicylic Acid-Ticagrelor-Unfractionated Heparin Complex Inhibits Early Graft Thrombosis

Background

Bypass graft surgery remains to be an important treatment option for left main and multivessel coronary artery disease. Approximately 2% of saphenous vein grafts are lost immediately after the coronary artery bypass graft operations and 12% in the first month due to thrombosis.

Aims

To administer one anticoagulant and two antiplatelet agents in a way that locally affects the vein graft before the bypass operation and to thereby analyse their effects on early graft thrombosis.

Study Design

Animal experimentation.

Methods

Since ticagrelor was used locally for the first time in this study, its efficacy in combination with other drugs (acetylsalicylic acid, acetylsalicylic acid and ticagrelor, and acetylsalicylic acid + ticagrelor + unfractionated heparin) was examined on rats including control (untreated) and sham (pluronic gel) group (n=14 for each group). Before the tunica adventitia layer of the femoral veins was bypassed to the femoral artery, it was coated with the drug-eluting pluronic F-127 gel. The presence or absence of thrombus in the vein graft samples was recorded under light microscopy. In vein graft preparations where thrombus was detected, the thrombus area (μm2) was calculated using the Axiovision software. Immunohistochemical staining was performed with the anti-rat von Willebrand factor polyclonal antibody kit.

Results

The number of preparations containing thrombus was significantly lower in the acetylsalicylic acid + ticagrelor + unfractionated heparin group than in the acetylsalicylic acid, control, and sham groups, according to the comparisons made on the 1st and 3rd days (p=0.001 and 0.02, respectively). von Willebrand factor staining was significantly lower in the acetylsalicylic acid + ticagrelor + unfractionated heparin group than in the other groups on the 3rd day (p=0.005).

Conclusion

Locally effective acetylsalicylic acid-ticagrelor-unfractionated heparin complex has been shown to significantly reduce thrombus formation in vein grafts in this experimental model. Local administration of these drugs, which are routinely administered orally just before stent implantations, on the vein graft before the bypass is performed can prevent the loss of vein grafts due to thrombus, thereby reducing the mortality and morbidity of these patients.

von Willebrand Factor Predicts Mortality in ACS Patients Treated with Potent P2Y12 Antagonists and is Inhibited by Aptamer BT200 Ex Vivo

BACKGROUND

 von Willebrand factor (VWF) is crucial for arterial thrombosis and its plasma levels are increased in acute coronary syndromes (ACSs). The effects of conventional platelet inhibitors are compromised by elevated VWF under high shear rates. BT200 is a third-generation aptamer that binds and inhibits the A1 domain of human VWF. This article aims to study whether VWF is a predictor of mortality in ACS patients under potent P2Y12 blocker therapy and to examine the effects of a VWF inhibiting aptamer BT200 and its concentrations required to inhibit VWF in plasma samples of patients with ACS.

METHODS

 VWF activity was measured in 320 patients with ACS, and concentration effect curves of BT200 were established in plasma pools containing different VWF concentrations.

RESULTS

 Median VWF activity in patients was 170% (interquartile range % confidence interval [CI]: 85-255) and 44% of patients had elevated (> 180%) VWF activity. Plasma levels of VWF activity predicted 1-year (hazard ratio [HR]: 2.68; 95% CI: 1.14-6.31; p < 0.024) and long-term (HR: 2.59; 95% CI: 1.10-6.09) mortality despite treatment with potent platelet inhibitors (dual-antiplatelet therapy with aspirin and prasugrel or ticagrelor). Although half-maximal concentrations were 0.1 to 0.2 µg/mL irrespective of baseline VWF levels, increasing concentrations (0.42-2.13 µg/mL) of BT200 were needed to lower VWF activity to < 20% of normal in plasma pools containing increasing VWF activity (p < 0.001).

CONCLUSION

 VWF is a predictor of all-cause mortality in ACS patients under contemporary potent P2Y12 inhibitor therapy. BT200 effectively inhibited VWF activity in a target concentration-dependent manner.

Inflammatory state does not affect the antiplatelet efficacy of potent P2Y12 inhibitors in ACS

Inflammation leads to atherosclerosis and acute coronary syndromes (ACS). We performed a prospective, observational study to assess association between the concentrations of inflammatory markers (high sensitivity C-reactive protein, hsCRP; high sensitivity interleukin6, hsIL-6; soluble CD40 ligand, sCD40 L) and platelet reactivity in 338 patients with ACS treated with ticagrelor and prasugrel. We also assessed whether hsCRP, hsIL-6, and sCD40 L are associated with standard inflammatory markers (white blood cell [WBC] and fibrinogen), and whether they differ according to patient diabetic status and pre-treatment with statins. Concentrations of hsCRP and concentrations of hsIL-6 and sCD40 L were assessed using turbidimetric assay and enzyme-linked immunosorbent assay, respectively. Platelet reactivity was measured using multiple electrode aggregometry. There was only a weak inverse correlation between hsIL-6 and platelet reactivity (r≤-0.125). In contrast, concentration of hsIL6 and hsCRP positively correlated with WBC and fibrinogen (r ≥ 0.199). Insulin-dependent diabetes mellitus (IDDM) was associated with higher concentration of hsIL-6 (p = .014), whereas pre-treatment with statins - with lower concentration of hsIL-6 (p = .035). In conclusion, inflammatory state does not affect the antiplatelet efficacy of potent P2Y12 inhibitors in the acute phase of ACS, confirming the safety and efficacy of potent P2Y12 inhibitors in patients with a high inflammatory burden.

Ticagrelor Removal by CytoSorb® in Patients Requiring Emergent or Urgent Cardiac Surgery: A UK-Based Cost-Utility Analysis

BACKGROUND

Acute coronary syndrome patients receiving dual antiplatelet therapy who need emergent or urgent cardiac surgery are at high risk of major bleeding, which can impair postoperative outcomes. CytoSorb^®, a blood purification technology based on adsorbent polymer, has been demonstrated to remove ticagrelor from blood during on-pump cardiac surgery.

OBJECTIVE

The aim of this study was to evaluate the cost utility of intraoperative removal of ticagrelor using CytoSorb versus usual care among patients requiring emergent or urgent cardiac surgery in the UK.

METHODS

A de novo decision analytic model, based on current treatment pathways, was developed to estimate the short- and long-term costs and outcomes. Results from randomised clinical trials and national standard sources such as National Health Service (NHS) reference costs were used to inform the model. Costs were estimated from the NHS and Personal Social Services perspective. Deterministic and probabilistic sensitivity analyses (PSAs) explored the uncertainty surrounding the input parameters.

RESULTS

In emergent cardiac surgery, intraoperative removal of ticagrelor using CytoSorb was less costly (£12,933 vs. £16,874) and more effective (0.06201vs. 0.06091 quality-adjusted life-years) than cardiac surgery without physiologic clearance of ticagrelor over a 30-day time horizon. For urgent cardiac surgery, the use of CytoSorb was less costly than any of the three comparators-delaying surgery for natural washout without adjunctive therapy, adjunctive therapy with short-acting antiplatelet agents, or adjunctive therapy with low-molecular-weight heparin. Results from the PSAs showed that CytoSorb has a high probability of being cost saving (99% in emergent cardiac surgery and 53-77% in urgent cardiac surgery, depending on the comparators). Cost savings derive from fewer transfusions of blood products and re-thoracotomies, and shorter stay in the hospital/intensive care unit.

CONCLUSIONS

The implementation of CytoSorb as an intraoperative intervention for patients receiving ticagrelor undergoing emergent or urgent cardiac surgery is a cost-saving strategy, yielding improvement in perioperative and postoperative outcomes and decreased health resource use.

Antimicrobial Properties on Non-Antibiotic Drugs in the Era of Increased Bacterial Resistance

In recent years, due to the dramatic increase in and global spread of bacterial resistance to a number of commonly used antibacterial agents, many studies have been directed at investigating drugs whose primary therapeutic purpose is not antimicrobial action. In an era where it is becoming increasingly difficult to find new antimicrobial drugs, it is important to understand these antimicrobial effects and their potential clinical implications. Numerous studies report the antibacterial activity of non-steroidal anti-inflammatory drugs, local anaesthetics, phenothiazines such as chlorpromazine, levomepromazine, promethazine, trifluoperazine, methdilazine and thioridazine, antidepressants, antiplatelets and statins. Several studies have explored a possible protective effect of statins inreducing the morbidity and mortality of many infectious diseases. Various non-antibiotic agents exhibit antimicrobial activity via multiple and different mechanisms of action. Further studies are required in the field to further investigate these antimicrobial properties in different populations. This is of paramount importance in the antimicrobial resistance era, where clinicians have limited therapeutic options to combat problematic infections.

Ticagrelor attenuates the increase of extracellular vesicle concentrations in plasma after acute myocardial infarction compared to clopidogrel

BACKGROUND

Platelet P2Y12 antagonist ticagrelor reduces mortality after acute myocardial infarction (AMI) compared to clopidogrel, but the underlying mechanism is unknown. Because activated platelets, leukocytes, and endothelial cells release proinflammatory and prothrombotic extracellular vesicles (EVs), we hypothesized that the release of EVs is more efficiently inhibited by ticagrelor compared to clopidogrel.

OBJECTIVES

We compared EV concentrations and EV procoagulant activity in plasma of patients after AMI treated with ticagrelor or clopidogrel.

METHODS

After percutaneous coronary intervention, 60 patients with first AMI were randomized to ticagrelor or clopidogrel. Flow cytometry was used to determine concentrations of EVs from activated platelets (CD61+ , CD62p+ ), fibrinogen+ , phosphatidylserine (PS+ ), leukocytes (CD45+ ), endothelial cells (CD31+ , 146+ ), and erythrocytes (CD235a+ ) in plasma at randomization, after 72 hours and 6 months of treatment. A fibrin generation test was used to determine EV procoagulant activity.

RESULTS

Concentrations of platelet, fibrinogen+ , PS+ , leukocyte, and erythrocyte EVs increased 6 months after AMI compared to the acute phase of AMI (P ≤ .03). Concentrations of platelet EVs were lower on ticagrelor compared to clopidogrel after 6 months (P = .03). Concentrations of fibrinogen+ , PS+ , and leukocyte EVs were lower on ticagrelor compared to clopidogrel both after 72 hours and 6 months (P ≤ .03). Concentrations of endothelial EVs and EV procoagulant activity did not differ between patient groups and over time (P ≥ .17).

CONCLUSIONS

Ticagrelor attenuates the increase of EV concentrations in plasma after acute myocardial infarction compared to clopidogrel. The ongoing release of EVs despite antiplatelet therapy might explain recurrent thrombotic events after AMI and worse clinical outcomes on clopidogrel compared to ticagrelor.

Ticagrelor and preconditioning in patients with stable coronary artery disease (TAPER-S): a randomized pilot clinical trial

Background

Ticagrelor is a reversibly binding, direct-acting, oral, P₂Y₁₂ antagonist used for the prevention of atherothrombotic events in patients with coronary artery disease (CAD). Ticagrelor blocks adenosine reuptake through the inhibition of equilibrative nucleoside transporter 1 (ENT-1) on erythrocytes and platelets, thereby facilitating adenosine-induced physiological responses such as an increase in coronary blood flow velocity. Meanwhile, adenosine plays an important role in triggering ischemic preconditioning through the activation of the A1 receptor. Therefore, an increase in ticagrelor-enhanced adenosine bioavailability may confer beneficial effects through mechanisms related to preconditioning activation and improvement of coronary microvascular dysfunction.

Methods

To determine whether ticagrelor can trigger ischemic preconditioning and influence microvascular function, we designed this prospective, open-label, pilot study that enrolled patients with stable multivessel CAD requiring staged, fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI). Participants will be randomized in 1:1 ratios either to ticagrelor (loading dose (LD) 180 mg, maintenance dose (MD) 90 mg bid) or to clopidogrel (LD 600 mg, MD 75 mg) from 3 to 1 days before the scheduled PCI. The PCI operators will be blinded to the randomization arm. The primary endpoint is the delta (difference) between ST segment elevations (in millimeters, mm) as assessed by intracoronary electrocardiogram (ECG) during the two-step sequential coronary balloon inflation in the culprit vessel. Secondary endpoints are 1) changes in coronary flow reserve (CFR), index of microvascular resistance (IMR), and FFR measured in the culprit vessel and reference vessel at the end of PCI, and 2) angina score during inflations. This study started in 2018 with the aim of enrolling 100 patients. Based on the rate of negative FFR up to 30% and a drop-out rate up to 10%, we expect to detect an absolute difference of 4 mm among the study arms in the mean change of ST elevation following repeated balloon inflations. All study procedures were reviewed and approved by the Ethical Committee of the Catholic University of Sacred Heart.

Discussion

Ticagrelor might improve ischemia tolerance and microvascular function compared to clopidogrel, and these effects might translate to better long-term clinical outcomes.

Trial registration

EudraCT No. 2016–004746-28. No. NCT02701140. 

Trial status

Information provided in this manuscript refers to the definitive version (n. 3.0) of the study protocol, dated 31 October 2017, and includes all protocol amendments. Recruitment started on 18 September 2018 and is currently ongoing. The enrollment is expected to be completed by the end of 2019.

Trial sponsor

Fondazione Policlinico Universitario A. Gemelli – Roma, Polo di Scienze Cardiovascolari e Toraciche, Largo Agostino Gemelli 8, 00168 Rome, Italy.

Outcomes Related to Antiplatelet Therapy in a High-Risk ST-Segment Elevation Myocardial Infarction Population: A Retrospective Real-World Analysis of an Italian ECMO Center

AIM

To evaluate outcomes related to antiplatelet therapy in patients with ST-elevation myocardial infarction (STEMI) admitted to the San Gerardo Hospital in Monza, an extracorporeal membrane oxygenation (ECMO) reference center in the Monza-Brianza area.

METHODS

This retrospective study enrolled patients with STEMI hospitalized between 2013 and 2017.

RESULTS

This study included 653 patients (mean age: 67.5 years, 71% male). Across the study period, ticagrelor use showed consistent increases, from 22% of patients during 2013 to 85% in 2017. Cardiac arrest prehospitalization occurred in 100 patients (15.3%), either at home (n = 85, 13.0%) or during transfer (n = 15, 2.3%); 46 patients underwent ECMO for refractory cardiac arrest. Rates of 90-day survival (hazard ratio [HR]: 2.4, 95% confidence interval [CI]: 1.3-4.4, P = .004) and ST resolution (odds ratio [OR]: 2.5, 95% CI: 1.6-4.1, P = .000) were higher with ticagrelor than with other antiplatelet agents. When analyzed by each agent, patients on ticagrelor had longer survival (HR: 0.4, 95% CI: 0.2-0.8, P = .008) than patients on clopidogrel and more frequent ST resolution than those on clopidogrel or prasugrel (OR: 0.4, 95% CI: 0.2-0.7, P = .002 and OR: 0.4, 95% CI: 0.2-0.7, P = .006). There was no difference in mortality between ticagrelor and prasugrel.

CONCLUSIONS

Changes in the treatment of high-risk patients with STEMI over time are in line with changes in treatment guidelines. In these patients, ticagrelor is associated with significantly improved 90-day mortality compared with clopidogrel.

Bioresorbable Vascular Scaffolds-Dead End or Still a Rough Diamond?

Percutaneous coronary interventions with stent-based restorations of vessel patency have become the gold standard in the treatment of acute coronary states. Bioresorbable vascular scaffolds (BVS) have been designed to combine the efficiency of drug-eluting stents (DES) at the time of implantation and the advantages of a lack of foreign body afterwards. Complete resolution of the scaffold was intended to enable the restoration of vasomotor function and reduce the risk of device thrombosis. While early reports demonstrated superiority of BVS over DES, larger-scale application and longer observation exposed major concerns about their use, including lower radial strength and higher risk of thrombosis resulting in higher rate of major adverse cardiac events. Further focus on procedural details and research on the second generation of BVS with novel properties did not allow to unequivocally challenge position of DES. Nevertheless, BVS still have a chance to present superiority in distinctive indications. This review presents an outlook on the available first and second generation BVS and a summary of results of clinical trials on their use. It discusses explanations for unfavorable outcomes, proposed enhancement techniques and a potential niche for the use of BVS.

Stratified Approaches to Antiplatelet Therapies Based on Platelet Reactivity Testing

Antiplatelet therapy with P2Y₁₂ receptor inhibitors (clopidogrel, prasugrel, ticagrelor, cangrelor) is a cornerstone of medical therapy after percutaneous coronary interventions. Significant prevalence of high on-treatment platelet reactivity (HTPR) on clopidogrel treatment led to introduction of more potent P2Y₁₂ inhibitors: prasugrel (a third generation thienopyridine), ticagrelor, and cangrelor (cyclopentyl-triazolo-pyrimidines). Nevertheless, more potent platelet inhibition and resulting low on-treatment platelet reactivity (LTPR) has led to increased risk of major bleeding events. These limitations resulted in a need for an individualized antiplatelet therapy approach. This review discusses the current role and future perspectives of diagnostic tools such as platelet function testing to optimize antiplatelet therapy with a focus on deescalating therapies to reduce bleeding risks.

Impact of Crystal Habit on Solubility of Ticagrelor

Drugs with poor biopharmaceutical performance are the main obstacle to the development and design of medicinal preparations. The anisotropic surface chemistry of different surfaces on the crystal influences its physical and chemical properties, such as solubility, tableting, etc. In this study, the antisolvent crystallization and rapid-cooling crystallization were carried out to tune the crystal habits of ticagrelor (TICA) form II. Different crystal habits of ticagrelor (TICA) form II (TICA-A, TICA-B, TICA-C, TICA-D, and TICA-E) were prepared and evaluated for solubility. The single-crystal diffraction (SXRD) indicated that TICA form II belongs to the triclinic P1 space group with four TICA molecules in the asymmetric unit. The TICA molecules are generated through intermolecular hydrogen bonds along the (010) direction, forming an infinite molecular chain, which are further stacked by hydrogen bonds between hydroxyethoxy side chains, forming molecular circles composed of six TICA molecules along bc directions. Thus, in the case of TICA form II, hydrogen bonds drive growth along one axis (b-axis), which results in the formation of mostly needle-shape crystals. Morphology and face indexation reveals that (001), (010) and (01-1) are the main crystal planes. Powder diffractions showed that five habits have the same crystal structure and different relative intensity of diffraction peak. The solubility of the obtained crystals showed the crystal habits affect their solubility. This work is helpful for studying the mechanism of crystal habit modification and its effect on solubility.

Differential Effects of Ticagrelor With or Without Aspirin on Platelet Reactivity and Coagulation Activation: A Randomized Trial in Healthy Volunteers

Dual antiplatelet therapy (DAPT) is standard in acute coronary heart disease but confers a bleeding risk. To compare the effects of ticagrelor‐monotherapy with ticagrelor‐based DAPT on hemostatic system activation, we conducted a randomized controlled trial in 44 volunteers using a loading‐dose regimen and measured platelet‐aggregometry triggered by adenosine diphosphate (multiple electrode aggregometry (MEA)‐ADP) and arachidonic acid (MEA‐AA), the vasodilator‐stimulated phosphoprotein (VASP), prothrombin fragment 1.2 (f1.2), and d‐Dimer. Ticagrelor‐based DAPT and ticagrelor‐monotherapy significantly decreased MEA‐ADP (Δmean: −51.4 (−56.9; −45.8) and −46.2 (−51.7; −40.7)) and VASP (Δmean: −70.3 (−76.2; −64.4) and −69.6 (−75.5; −63.7)) at 2 hours and over 24 hours. MEA‐AA was reduced significantly by both treatments (Δmean: −72.9 (−80.6; −65.3) and −25.7 (−33.3; −18.0)) at 2 hours, and stronger by ticagrelor‐based DAPT over 24 hours. Both treatments decreased f1.2 (geometric mean ratio (GMR): 0.92 (0.84; 1.01) and 0.88 (0.80; 0.96)) and d‐Dimer (GMR: 0.89 (0.86; 0.92) and 0.91 (0.88; 0.94)) at 2 hours and d‐Dimer over 24 hours. Ticagrelor‐monotherapy and ticagrelor‐based DAPT comparably affect hemostatic system activation.

Role of NF-κB in Platelet Function

Platelets are megakaryocyte-derived fragments lacking nuclei and prepped to maintain primary hemostasis by initiating blood clots on injured vascular endothelia. Pathologically, platelets undergo the same physiological processes of activation, secretion, and aggregation yet with such pronouncedness that they orchestrate and make headway the progression of atherothrombotic diseases not only through clot formation but also via forcing a pro-inflammatory state. Indeed, nuclear factor-κB (NF-κB) is largely implicated in atherosclerosis and its pathological complication in atherothrombotic diseases due to its transcriptional role in maintaining pro-survival and pro-inflammatory states in vascular and blood cells. On the other hand, we know little on the functions of platelet NF-κB, which seems to function in other non-genomic ways to modulate atherothrombosis. Therein, this review will resemble a rich portfolio for NF-κB in platelets, specifically showing its implications at the levels of platelet survival and function. We will also share the knowledge thus far on the effects of active ingredients on NF-κB in general, as an extrapolative method to highlight the potential therapeutic targeting of NF-κB in coronary diseases. Finally, we will unzip a new horizon on a possible extra-platelet role of platelet NF-κB, which will better expand our knowledge on the etiology and pathophysiology of atherothrombosis.

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.

Systemic Design and Evaluation of Ticagrelor-Loaded Nanostructured Lipid Carriers for Enhancing Bioavailability and Antiplatelet Activity

Ticagrelor (TGL), a P2Y12 receptor antagonist, is classified as biopharmaceutics classification system (BCS) class IV drug due to its poor solubility and permeability, resulting in low oral bioavailability. Nanostructured lipid carriers (NLC) are an efficient delivery system for the improvement of bioavailability of BCS class IV drugs. Hence, we prepared TGL-loaded NLC (TGL-NLC) to enhance the oral bioavailability and antiplatelet activity of TGL with a systemic design approach. The optimized TGL-NLC with Box-Behnken design showed a small particle size of 87.6 nm and high encapsulation efficiency of 92.1%. Scanning electron microscope (SEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) were performed to investigate the characteristics of TGL-NLC. Furthermore, TGL-NLC exhibited biocompatible cytotoxicity against Caco-2 cells. Cellular uptake of TGL-NLC was 1.56-fold higher than that of raw TGL on Caco-2 cells. In pharmacokinetic study, the oral bioavailability of TGL-NLC was 254.99% higher than that of raw TGL. In addition, pharmacodynamic study demonstrated that the antiplatelet activity of TGL-NLC was superior to that of raw TGL, based on enhanced bioavailability of TGL-NLC. These results suggest that TGL-NLC can be applied for efficient oral absorption and antiplatelet activity of TGL.

Effects of ticagrelor on the sodium/calcium exchanger 1 (NCX1) in cardiac derived H9c2 cells

Ticagrelor is a direct acting and reversibly binding P2Y₁₂ antagonist approved for the prevention of thromboembolic events. Clinical effects of ticagrelor cannot be simply accounted for by pure platelet inhibition, and off-target mechanisms can potentially play a role. In particular, recent evidence suggests that ticagrelor may also influence heart function and improve the evolution of myocardial ischemic injury by more direct effects on myocytes. The cardiac sodium/calcium exchanger 1 (NCX1) is a critical player in the generation and control of calcium (Ca²⁺) signals, which orchestrate multiple myocyte activities in health and disease. Altered expression and/or activity of NCX1 can have profound consequences for the function and fate of myocytes. Whether ticagrelor affects cardiac NCX1 has not been investigated yet. To explore this hypothesis, we analyzed the expression, localization and activity of NCX1 in the heart derived H9c2-NCX1 cells following ticagrelor exposure. We found that ticagrelor concentration- and time-dependently reduced the activity of the cardiac NCX1 in H9c2 cells. In particular, the inhibitory effect of ticagrelor on the Ca²⁺-influx mode of NCX1 was evident within 1 h and further developed after 24 h, when NCX1 activity was suppressed by about 55% in cells treated with 1 μM ticagrelor. Ticagrelor-induced inhibition of exchanger activity was reached at clinically relevant concentrations, without affecting the expression levels and subcellular distribution of NCX1. Collectively, these findings suggest that cardiac NCX1 is a new downstream target of ticagrelor, which may contribute to the therapeutic profile of ticagrelor in clinical practice.

Platelet Reactivity And Circulating Platelet-Derived Microvesicles Are Differently Affected By P2Y12 Receptor Antagonists

Background: Platelet-derived microvesicles (PMVs), shed from platelet surface membranes, constitute the majority of circulating microvesicles and have been implicated in procoagulant, pro-inflammatory and pro-atherosclerotic effects. Our aim was to compare plasma PMVs numbers in relation to platelet reactivity during dual antiplatelet therapy (DAPT) with various P2Y₁₂ adenosine diphosphate (ADP) receptor antagonists. Methods: In pre-discharge men treated with DAPT for an acute coronary syndrome, plasma PMVs were quantified by flow cytometry on the basis of CD62P (P-selectin) and CD42 (glycoprotein Ib) positivity, putative indices of PMVs release from activated and all platelets, respectively. ADP-induced platelet aggregation was measured by multiple-electrode aggregometry. Results: Clinical characteristics were similar in patients on clopidogrel (n=16), prasugrel (n=10) and ticagrelor (n=12). Platelet reactivity was comparably reduced on ticagrelor or prasugrel versus clopidogrel (p<0.01). Compared to clopidogrel-treated patients, CD42⁺/CD62P⁺ PMVs counts were 3-4-fold lower in subjects receiving ticagrelor (p=0.001) or prasugrel (p<0.05), while CD42⁺ PMVs were significantly reduced on ticagrelor (by about 6-fold, p<0.001), but not prasugrel (p=0.3). CD42⁺/CD62P⁺ PMVs numbers correlated positively to the ADP-induced aggregation on clopidogrel (p<0.01) or prasugrel (p<0.05), which was absent in ticagrelor users (p=0.8). CD42⁺ PMVs counts were unrelated to platelet reactivity (p>0.5). Conclusions: Higher antiplatelet potency of prasugrel and ticagrelor versus clopidogrel is associated with decreased plasma CD42⁺/CD62P⁺ PMVs numbers. However, in contrast to thienopyridines, the association of reduced CD42⁺/CD62P⁺ PMVs counts with ticagrelor use appears independent of its anti-aggregatory effect. Despite similar platelet-inhibitory activity of ticagrelor and prasugrel, only the treatment with ticagrelor seems associated with lower total PMVs release. Our preliminary findings may suggest a novel pleiotropic effect of ticagrelor extending beyond pure anti-aggregatory properties of the drug.

Randomized controlled trial protocol to investigate the antiplatelet therapy effect on extracellular vesicles (AFFECT EV) in acute myocardial infarction

Activated platelets contribute to thrombosis and inflammation by the release of extracellular vesicles (EVs) exposing P-selectin, phosphatidylserine (PS) and fibrinogen. P2Y12 receptor antagonists are routinely administered to inhibit platelet activation in patients after acute myocardial infarction (AMI), being a combined antithrombotic and anti-inflammatory therapy. The more potent P2Y12 antagonist ticagrelor improves cardiovascular outcome in patients after AMI compared to the less potent clopidogrel, suggesting that greater inhibition of platelet aggregation is associated with better prognosis. The effect of ticagrelor and clopidogrel on the release of EVs from platelets and other P2Y12-exposing cells is unknown. This study compares the effects of ticagrelor and clopidogrel on (1) the concentrations of EVs from activated platelets (primary end point), (2) the concentrations of EVs exposing fibrinogen, exposing PS, from leukocytes and from endothelial cells (secondary end points) and (3) the procoagulant activity of plasma EVs (tertiary end points) in 60 consecutive AMI patients. After the percutaneous coronary intervention, patients will be randomized to antiplatelet therapy with ticagrelor (study group) or clopidogrel (control group). Blood will be collected from patients at randomization, 48 hours after randomization and 6 months following the index hospitalization. In addition, 30 age- and gender-matched healthy volunteers will be enrolled in the study to investigate the physiological concentrations and procoagulant activity of EVs using recently standardized protocols and EV-dedicated flow cytometry. Concentrations of EVs will be determined by flow cytometry. Procoagulant activity of EVs will be determined by fibrin generation test. The compliance and response to antiplatelet therapy will be assessed by impedance aggregometry. We expect that plasma from patients treated with ticagrelor (1) contains lower concentrations of EVs from activated platelets, exposing fibrinogen, exposing PS, from leukocytes and from endothelial cells and (2) has lower procoagulant activity, when compared to patients treated with clopidogrel. Antiplatelet therapy effect on EVs may identify a new mechanism of action of ticagrelor, as well as create a basis for future studies to investigate whether lower EV concentrations are associated with improved clinical outcomes in patients treated with P2Y12 antagonists.