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1.
Platelet inhibitory activity, tolerability, and safety of vicagrel, a novel thienopyridine P2Y12 inhibitor.
Li, H, Chen, H, Chen, W, Xu, H, Yuan, F, Yang, M, Sun, H, Yang, J, Liu, Y, Lai, X, et al
Medicine. 2020;(4):e18683
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Abstract
Vicagrel is a new antiplatelet pro-drug based on clopidogrel sulfur lactone metabolites. The purpose of the study was to evaluate the safety, tolerability, and pharmacodynamics (PD) of vicagrel in healthy Chinese subjects.This study was designed as a single-center, randomized, double-blind, placebo-controlled, single oral ascending dose study. Fifty nine subjects were assigned to 6 vicagrel dose cohorts (5, 10, 20, 40, 60, and 75 mg), and 8 subjects were assigned to 75 mg clopidogrel. Within each vicagrel dose cohort, the 10 subjects (9 in the 75 mg cohort) were randomized 4:1 to receive vicagrel or placebo. Platelet function was assessed using VerifyNow P2Y12. ΔP2Y12 reaction units (ΔPRU) and percent inhibition platelet aggregation (%IPA) were used to evaluate the PD of vicagrel.Although the number of adverse events (AEs) increased with vicagrel dose, none were considered serious, suggesting that vicagrel is safe and well-tolerated. The ΔPRU and %IPA patterns suggest that inhibition of ADP-induced platelet aggregation increased in a dose-dependent manner across the 10 to 40 mg dose range. The inhibitory effect was nearly complete at 4 hours (mean %IPA 87.9%-93.0%, mean ΔPRU 206.6-240.0) for doses of 40 to 75 mg of vicagrel. In contrast, for 5 mg vicagrel and 75 mg clopidogrel, there were no measurable effects on platelet aggregation throughout the study.The results suggest that vicagrel at 40 to 75 mg inhibits ADP-induced platelet aggregation, with a fast onset of action and significantly greater potency than clopidogrel. These findings indicate that vicagrel may be a highly effective and well-tolerated antiplatelet agent.
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Cangrelor, Tirofiban, and Chewed or Standard Prasugrel Regimens in Patients With ST-Segment-Elevation Myocardial Infarction: Primary Results of the FABOLUS-FASTER Trial.
Gargiulo, G, Esposito, G, Avvedimento, M, Nagler, M, Minuz, P, Campo, G, Gragnano, F, Manavifar, N, Piccolo, R, Tebaldi, M, et al
Circulation. 2020;(5):441-454
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Abstract
BACKGROUND Standard administration of newer oral P2Y12 inhibitors, including prasugrel or ticagrelor, provides suboptimal early inhibition of platelet aggregation (IPA) in patients with ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention. We aimed to investigate the effects of cangrelor, tirofiban, and prasugrel, administered as chewed or integral loading dose, on IPA in patients undergoing primary percutaneous coronary intervention. METHODS The FABOLUS-FASTER trial (Facilitation Through Aggrastat or Cangrelor Bolus and Infusion Over Prasugrel: A Multicenter Randomized Open-Label Trial in Patients with ST-Elevation Myocardial Infarction Referred for Primary Percutaneous Intervention) is an investigator-initiated, multicenter, open-label, randomized study. A total of 122 P2Y12-naive patients with ST-segment-elevation myocardial infarction were randomly allocated (1:1:1) to cangrelor (n=40), tirofiban (n=40) (both administered as bolus and 2-hour infusion followed by 60 mg of prasugrel), or 60-mg loading dose of prasugrel (n=42). The latter group underwent an immediate 1:1 subrandomization to chewed (n=21) or integral (n=21) tablets administration. The trial was powered to test 3 hypotheses (noninferiority of cangrelor compared with tirofiban using a noninferiority margin of 9%, superiority of both tirofiban and cangrelor compared with chewed prasugrel, and superiority of chewed prasugrel as compared with integral prasugrel, each with α=0.016 for the primary end point, which was 30-minute IPA at light transmittance aggregometry in response to 20 μmol/L adenosine diphosphate. RESULTS At 30 minutes, cangrelor did not satisfy noninferiority compared with tirofiban, which yielded superior IPA over cangrelor (95.0±8.9 versus 34.1±22.5; P<0.001). Cangrelor or tirofiban were both superior to chewed prasugrel (IPA, 10.5±11.0; P<0.001 for both comparisons), which did not provide higher IPA over integral prasugrel (6.3±11.4; P=0.47), despite yielding higher prasugrel active metabolite concentration (ng/mL; 62.3±82.6 versus 17.1±43.5; P=0.016). CONCLUSIONS Cangrelor provided inferior IPA compared with tirofiban; both treatments yielded greater IPA compared with chewed prasugrel, which led to higher active metabolite concentration but not greater IPA compared with integral prasugrel. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02978040; URL: https://www.clinicaltrialsregister.eu; EudraCT 2017-001065-24.
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Antiplatelet Effect of Carbon Monoxide Is Mediated by NAD+ and ATP Depletion.
Kaczara, P, Sitek, B, Przyborowski, K, Kurpinska, A, Kus, K, Stojak, M, Chlopicki, S
Arteriosclerosis, thrombosis, and vascular biology. 2020;(10):2376-2390
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Abstract
OBJECTIVES Carbon monoxide (CO) produced by haem oxygenases or released by CO-releasing molecules (CORM) affords antiplatelet effects, but the mechanism involved has not been defined. Here, we tested the hypothesis that CO-induced inhibition of human platelet aggregation is mediated by modulation of platelet bioenergetics. Approach and Results: To analyze the effects of CORM-A1 on human platelet aggregation and bioenergetics, a light transmission aggregometry, Seahorse XFe technique and liquid chromatography tandem-mass spectrometry-based metabolomics were used. CORM-A1-induced inhibition of platelet aggregation was accompanied by the inhibition of mitochondrial respiration and glycolysis. Interestingly, specific inhibitors of these processes applied individually, in contrast to combined treatment, did not inhibit platelet aggregation considerably. A CORM-A1-induced delay of tricarboxylic acid cycle was associated with oxidized nicotinamide adenine dinucleotide (NAD+) depletion, compatible with the inhibition of oxidative phosphorylation. CORM-A1 provoked an increase in concentrations of proximal (before GAPDH [glyceraldehyde 3-phosphate dehydrogenase]), but not distal glycolysis metabolites, suggesting that CO delayed glycolysis at the level of NAD+-dependent GAPDH; however, GAPDH activity was directly not inhibited. In the presence of exogenous pyruvate, CORM-A1-induced inhibition of platelet aggregation and glycolysis were lost, but were restored by the inhibition of lactate dehydrogenase, involved in cytosolic NAD+ regeneration, pointing out to the key role of NAD+ depletion in the inhibition of platelet bioenergetics by CORM-A1. CONCLUSIONS The antiplatelet effect of CO is mediated by inhibition of mitochondrial respiration-attributed to the inhibition of cytochrome c oxidase, and inhibition of glycolysis-ascribed to cytosolic NAD+ depletion.
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Platelet function and activation markers in primary hypercholesterolemia treated with anti-PCSK9 monoclonal antibody: A 12-month follow-up.
Barale, C, Bonomo, K, Frascaroli, C, Morotti, A, Guerrasio, A, Cavalot, F, Russo, I
Nutrition, metabolism, and cardiovascular diseases : NMCD. 2020;(2):282-291
Abstract
BACKGROUND AND AIMS In the association between hypercholesterolemia (HC) and thrombotic risk platelet hyper-reactivity plays an important role. The inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) to reduce plasma LDL-cholesterol merges as effective therapeutic strategy to prevent cardiovascular (CV) events. Aim of this study was to verify whether a treatment up to 12 months with the monoclonal antibodies (mAbs) anti-PCSK9 influences platelet function in primary HC. METHODS AND RESULTS In patients affected by primary HC (n = 24), all on background of statin and 17 on acetyl salicylic acid (ASA), platelet function parameters were evaluated at baseline up to 12 months of treatment with the mAb anti-PCSK9 alirocumab or evolocumab. From baseline, the treatment with anti-PCSK9 mAbs: i) in ASA HC patients, significantly decreased platelet aggregation detected in platelet-rich plasma by light transmission aggregometry and in whole blood Platelet Function Analyzer-100 assay; ii) in all HC patients, significantly decreased platelet membrane expression of CD62P and plasma levels of the in vivo platelet activation markers soluble CD40 Ligand, Platelet Factor-4, and soluble P-Selectin. Furthermore, CD62P expression, and sP-Selectin, PF-4, sCD40L levels significantly correlated with serum PCSK9. CONCLUSION Besides markedly lowering LDL-c levels, our results suggest that HC patients benefit from anti-PCSK9 mAb treatment also for reducing platelet reactivity and increasing platelet sensitivity to the inhibitory effects of aspirin. These effects on platelets could play a role in the reduction of CV event incidence in patients treated with PCSK9 inhibitors.
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Impact of Continuous P2Y12 Inhibition Tailoring in Acute Coronary Syndrome and Genetically Impaired Clopidogrel Absorption.
Samardzic, J, Bozina, N, Skoric, B, Ganoci, L, Krpan, M, Petricevic, M, Pasalic, M, Bozina, T, Pavasovic, S, Cikes, M, et al
Journal of cardiovascular pharmacology. 2020;(2):174-179
Abstract
Clopidogrel is still widely used in acute coronary syndrome despite the development of more potent P2Y12 inhibitors. Previously, we conducted a trial that evaluated serial clopidogrel dose adjustment based on platelet function testing in acute coronary syndrome patients with initial high on-treatment platelet reactivity (HTPR). In this substudy, we performed post hoc analysis of the effect of ABCB1 genetic variants C3435T and G2677T/A on platelet inhibition and outcomes. There were no differences in the proportion of HTPR patients among C3435T carriers and noncarriers in both interventional and control group. G2677T carriers expressed significantly higher proportion of HTPR pattern throughout 12-month follow-up in the control group with no difference in the interventional group. There was no difference in ischemic outcomes between C3435T and G2677T carriers and noncarriers in both groups of patients. The results indicate that ABCB1 genotyping is not useful to guide clopidogrel therapy tailoring to improve high-risk patient management.
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Intake of aspirin prior to metamizole does not completely prevent high on treatment platelet reactivity.
Pfrepper, C, Dietze, C, Remane, Y, Bertsche, T, Schiek, S, Kaiser, T, Gockel, I, Josten, C, Petros, S
European journal of clinical pharmacology. 2020;(4):483-490
Abstract
PURPOSE Metamizole can sterically inhibit aspirin (ASA) from binding to cyclooxygenase 1 (COX1). It is recommended that ASA should be taken 30 min prior to metamizole to maintain the irreversible inhibition of arachidonic acid (AA)-induced platelet aggregation. We aimed to analyse the inhibitory effect of ASA and metamizole on AA-induced platelet aggregation over the course of the day. METHODS We analysed hospitalized patients who ingested ASA at least 30 min prior to metamizole (recommended dosing group, n = 15), metamizole prior or simultaneously with ASA (not recommended dosing group, n = 16) and patients with unknown or mixed intake (mixed dosing group, n = 5). AA-induced light transmission (LTA) and impedance aggregometry (IA) were measured before, 1-2 and 5-6 h after the intake of ASA ± metamizole. RESULTS Maximum AA-induced LTA prior to the intake of ASA was significantly lower and the rate of high on treatment platelet reactivity (HTPR) higher in the recommended compared with the not recommended dosing group (19.6% vs. 46.9%, p = 0.011 and 4/15 vs. 12/16 patients, p = 0.017). There was no difference when IA was used. Maximum AA-induced LTA after the intake of ASA ± metamizole was lower in patients in the not recommended but not in the recommended dosing group. All patients with HTPR in the recommended dosing group had regular inhibition of AA-induced LTA after discontinuation of metamizole. CONCLUSION Co-medication of ASA and metamizole significantly influences platelet inhibition with variations during the day and can cause HTPR in patients taking ASA prior to metamizole or simultaneously.
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Impact of low-dose prasugrel on platelet reactivity and cardiac dysfunction in acute coronary syndrome patients requiring primary drug-eluting stent implantation: A randomized comparative study.
Kitano, D, Takayama, T, Fukamachi, D, Migita, S, Morikawa, T, Tamaki, T, Kojima, K, Mineki, T, Murata, N, Akutsu, N, et al
Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions. 2020;(1):E8-E16
Abstract
OBJECTIVE The aim of this study was to compare how prasugrel and clopidogrel affect platelet aggregation reactivity, cardiac enzyme release, cardiac remodeling, and the formation of in-stent thrombi after primary percutaneous coronary intervention (PCI). BACKGROUND The advantages of using prasugrel over clopidogrel in cardiac injury following acute coronary syndrome (ACS) remain unclear. METHODS A total of 78 ACS patients were randomly allocated into clopidogrel (300 mg loading/75 mg maintenance) or prasugrel (20 mg loading/3.75 mg maintenance) treatment groups, followed by undergoing primary PCI. Platelet reactivity and cardiac enzymes were measured before and after primary PCI. Moreover, cardiac function was measured by ultrasound echocardiography and coronary angioscopic observation was after primary PCI up to 8 months later. RESULTS Antiplatelet reactivity in the prasugrel treatment group reached optimal levels (P2Y12 reaction units [PRU] less than 262) immediately after the administration and was maintained even at 8 months, independently of the CYP2C19 genotype. Prasugrel treatment significantly suppressed creatine kinase elevation compared to clopidogrel treatment (median value 404 IU/L to 726 IU/L vs. 189 IU/L to 1,736 IU/L, p = 0.018 for maximum values) and reduced left ventricular mass (217.2-168.8 g in prasugrel, p = 0.045; 196.9-176.4 g in clopidogrel, p = 0.061). There were no significant differences in the incidence of in-stent attached thrombi between the two groups. CONCLUSIONS Compared to clopidogrel, prasugrel produced a stable platelet aggregation inhibitory effect in patients with ACS regardless of CYP2C19 genotype, reduced cardiac enzyme release, and prevented cardiac remodeling after ACS.
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Consumption of plant extract supplement reduces platelet activating factor-induced platelet aggregation and increases platelet activating factor catabolism: a randomised, double-blind and placebo-controlled trial.
Gavriil, L, Detopoulou, M, Petsini, F, Antonopoulou, S, Fragopoulou, E
The British journal of nutrition. 2019;(9):982-991
Abstract
Platelet-activating factor (PAF) is a potent mediator of inflammation that plays a crucial role in atherosclerosis. The purpose of this study was to evaluate the effect of a dietary supplement containing mainly plant extracts on PAF actions and metabolism in healthy volunteers. A double-blind, placebo-controlled, 8 weeks' duration study was performed. Healthy volunteers were randomly allocated into the supplement or the placebo group and fifty-eight of them completed the study. The supplement contained plant extracts (Aloe gel, grape juice, Polygonum cuspidatum) and vitamins. The activities of PAF metabolic enzymes: the two isoforms of acetyl-CoA:lyso-PAF acetyltransferase, cytidine 5'-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-cholinephosphotransferase) and platelet-activating factor-acetylhydrolase (PAF-AH) in leucocytes and lipoprotein associated phospholipase-A2 in plasma were measured along with several markers of endothelial function. Platelet aggregation against PAF, ADP and thrombin receptor activating peptide was measured in human platelet-rich plasma by light transmission aggregometry. No difference was observed on soluble vascular cell adhesion molecule-1, sP-selectin and IL-6 levels at the beginning or during the study period between the two groups. Concerning PAF metabolism enzymes' activity, no difference was observed at baseline between the groups. PAF-AH activity was only increased in the supplement group at 4 and 8 weeks compared with baseline levels. In addition, supplement consumption led to lower platelet sensitivity against PAF and ADP compared with baseline levels. However, a trial effect was only observed when platelets were stimulated by PAF. In conclusion, supplementation with plant extracts and vitamins ameliorates platelet aggregation primarily against PAF and secondarily against ADP and affects PAF catabolism by enhancing PAF-acetylhydrolase activity in healthy subjects.
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The relation between ABO blood types and clinical and platelet function parameters in patients who underwent percutaneous coronary intervention.
Timur, AA, Barnard, J, Murugesan, G, Gandhi, S, Bhatt, DL, Kottke-Marchant, K
Coronary artery disease. 2019;(1):51-58
Abstract
BACKGROUND ABO blood groups have been associated with venous thromboembolism and arterial thrombosis. Although platelets play key roles in thrombogenesis, the relation between ABO groups and platelets is not well known and was investigated in this study. PATIENTS AND METHODS ABO blood type information was retrospectively obtained for 206 patients who underwent percutaneous coronary intervention (PCI) and received dual antiplatelet therapy with aspirin and clopidogrel. Platelet function was measured using VerifyNow system, light transmission aggregometry, thromboxane B2, urinary 11-dehydrothromboxane B2, and vasodilator-stimulated phosphoprotein phosphorylation assays. Samples were also tested following treatment with 10 and 30 µmol/l of aspirin or 30 and 100 µmol/l of P2Y12 inhibitor 2-methylthioadenosine 5'-monophosphate triethylammonium salt hydrate (2-MeSAMP). Forty-four clinical and 30 platelet function parameters were analyzed. Patients were categorized as aspirin or clopidogrel poor responder (PR) according to cutoff levels of each test. RESULTS Blood type A was significantly associated with myocardial infarction (MI) history [odds ratio (OR)=2.50, 95% confidence interval (CI)=1.37-4.58, P=0.003], higher baseline troponin T and creatine kinase-MB (CK-MB) index, post-PCI CK-MB index, and platelet reactivity index (PRI), and being PR against 2-MeSAMP (OR=5.75, 95% CI=1.51-21.90, P=0.010). Blood type O was associated with higher arachidonic acid-induced platelet aggregation and negatively associated with MI history (OR=0.47, 95% CI=0.26-0.84, P=0.010), PRI and being PR against clopidogrel (OR=0.54, 95% CI=0.30-0.99, P=0.043) and 2-MeSAMP (OR=0.16, 95% CI=0.03-0.76, P=0.021). CONCLUSION Blood type A was found as a risk factor for MI. Higher arachidonic acid-induced aggregation in group O and higher PRI in group A against aspirin and P2Y12 inhibitor treatment, respectively, may suggest alternative antiplatelet therapies for PRs with these blood types.
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Adrenoceptor α2A signalling countervails the taming effects of synchronous cyclic nucleotide-elevation on thrombin-induced human platelet activation and aggregation.
Fälker, K, Ljungberg, LU, Kardeby, C, Lindkvist, M, Sirsjö, A, Grenegård, M
Cellular signalling. 2019;:96-109
Abstract
The healthy vascular endothelium constantly releases autacoids which cause an increase of intracellular cyclic nucleotides to tame platelets from inappropriate activation. Elevating cGMP and cAMP, in line with previous reports, cooperated in the inhibition of isolated human platelet intracellular calcium-mobilization, dense granules secretion, and aggregation provoked by thrombin. Further, platelet alpha granules secretion and, most relevant, integrin αIIaβ3 activation in response to thrombin are shown to be prominently affected by the combined elevation of cGMP and cAMP. Since stress-related sympathetic nervous activity is associated with an increase in thrombotic events, we investigated the impact of epinephrine in this setting. We found that the assessed signalling events and functional consequences were to various extents restored by epinephrine, resulting in full and sustained aggregation of isolated platelets. The restoring effects of epinephrine were abolished by either interfering with intracellular calcium-elevation or with PI3-K signalling. Finally, we show that in our experimental setting epinephrine likewise reconstitutes platelet aggregation in heparinized whole blood, which may indicate that this mechanism could also apply in vivo.