1
|
Balaji S, Patnaik YR, Surin WR. Off-target effect of high-dose sildenafil on adenosine 5'- diphosphate and collagen-induced platelet activation through mitogen-activated protein kinase pathway in treated BALB/C mice and in vitro experiments: A preliminary study. Indian J Pharmacol 2024; 56:136-140. [PMID: 38808925 PMCID: PMC11161001 DOI: 10.4103/ijp.ijp_312_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 11/15/2023] [Accepted: 03/18/2024] [Indexed: 05/30/2024] Open
Abstract
ABSTRACT Sildenafil, a common over-the-counter pill often self-administered at high doses for erectile dysfunction, has been reported to rarely cause prothrombotic events and sudden cardiac death in a few case reports. Therefore, we investigated the in vitro and in vivo effect of sildenafil treatment and dosage on platelet activation and mitogen-activated protein kinase (MAPK) phosphorylation. BALB/C mice were segregated into four groups, each having four mice each (control, low [3.25 mg/kg], medium [6.5 mg/kg], and high [13 mg/kg] sildenafil), and after the treatment, blood was drawn from each mouse and washed platelets prepared. Washed platelets were incubated with CD41 PE-Cy7 and Phospho-p38 MAPK PE antibodies and analyzed using a flow cytometer for platelet activation and adenosine 5'- diphosphate (ADP)/collagen-induced MAPK phosphorylation. Washed platelets obtained from the venous blood of 18 human volunteers, were incubated with PAC-1 FITC and Phospho-p38 MAPK PE antibodies, and platelet activation (ADP and collagen), followed by flow cytometry analysis. There was a significant increase in both platelet activation as well as MAPK phosphorylation in the presence of collagen in the high-dose (13 mg/kg) sildenafil group (P = 0.000774). Further, increased platelet activation was observed in samples that were treated with high-dose sildenafil as compared to the untreated samples (P < 0.00001). These studies show the risk of prothrombotic episodes in patients on high-dose sildenafil (100 mg), in those with even mild endothelial dysfunction due to ADP, and collagen-induced platelet activation through MAPK phosphorylation, which was not seen in the low-and intermediate-dose cohorts.
Collapse
Affiliation(s)
- Sudharshanan Balaji
- Department of Urology, Government Kilpauk Medical College, Chennai, Tamil Nadu, India
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Yash Raj Patnaik
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka, India
| | - William Rasican Surin
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka, India
| |
Collapse
|
2
|
Jantsch MH, Doleski PH, Viana AR, da Silva JLG, Passos DF, Cabral FL, Manzoni AG, Ebone RDS, Soares ABU, de Andrade CM, Schetinger MRC, Leal DBR. Effects of clopidogrel bisulfate on B16-F10 cells and tumor development in a murine model of melanoma. Biochem Cell Biol 2023; 101:443-455. [PMID: 37163764 DOI: 10.1139/bcb-2022-0249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
Abstract
Metastatic melanoma is a very aggressive skin cancer. Platelets are constituents of the tumor microenvironment and, when activated, contribute to cancer progression, especially metastasis and inflammation. P2Y12 is an adenosine diphosphate receptor that triggers platelet activation. Inhibition of P2Y12 by clopidogrel bisulfate (CB) decreases platelet activation, which is also controlled by the extracellular concentration and the metabolism of purines by purinergic enzymes. We evaluated the effects of CB on the viability and proliferation of cultured B16-F10 cells. We also used a metastatic melanoma model with C57BL-6 mice to evaluate cancer development and purine metabolism modulation in platelets. B16-F10 cells were administered intraperitoneally to the mice. Two days later, the animals underwent a 12-day treatment with CB (30 mg/kg by gavage). We have found that CB reduced cell viability and proliferation in B16-F10 culture in 72 h at concentrations above 30 µm. In vivo, CB decreased tumor nodule counts and lactate dehydrogenase levels and increased platelet purine metabolism. Our results showed that CB has significant effects on melanoma progression.
Collapse
Affiliation(s)
- Matheus Henrique Jantsch
- Laboratório de Imunobiologia Experimental e Aplicada (LABIBIO), Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Instituto Federal Farroupilha, Campus Santo Ângelo, Santo Ângelo, RS, Brazil
| | - Pedro Henrique Doleski
- Laboratório de Imunobiologia Experimental e Aplicada (LABIBIO), Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Altevir Rossato Viana
- Programa de Pós-graduação em Nanociências; Laboratório de Biociências. Universidade Franciscana, Santa Maria, RS, Brazil
| | - Jean Lucas Gutknecht da Silva
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Daniela Ferreira Passos
- Laboratório de Imunobiologia Experimental e Aplicada (LABIBIO), Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Fernanda Licker Cabral
- Laboratório de Imunobiologia Experimental e Aplicada (LABIBIO), Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Alessandra Guedes Manzoni
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Renan da Silva Ebone
- Laboratório de Imunobiologia Experimental e Aplicada (LABIBIO), Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | | | - Cínthia Melazzo de Andrade
- Laboratório de Imunobiologia Experimental e Aplicada (LABIBIO), Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Hospital Veterinário, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Maria Rosa Chitolina Schetinger
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Daniela Bitencourt Rosa Leal
- Laboratório de Imunobiologia Experimental e Aplicada (LABIBIO), Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| |
Collapse
|
3
|
Djordjevic N. Genotyping genetic variants of CYP2C19 for precision antiplatelet dosing: state of the art and future perspectives. Expert Opin Drug Metab Toxicol 2022; 18:817-830. [PMID: 36606363 DOI: 10.1080/17425255.2022.2166486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Clopidogrel is the only antiplatelet agent whose activity is significantly affected by CYP2C19 polymorphism. AREAS COVERED This review has summarized the available evidence on the clinically significant association between CYP2C19 polymorphism and clopidogrel-based therapy; reviewed the current recommendations for clinical use of CYP2C19 genotype test results in patients on clopidogrel treatment; and discussed possible pitfalls of routine application, and future perspectives of antiplatelets pharmacogenetics. EXPERT OPINION The available body of evidence, reflected in several meta-analyses and high-quality clinical practice guidelines, shows that the presence of CYP2C19 LOF alleles, especially CYP2C19*2, correlates with impaired activation of clopidogrel and variable platelet inhibition, followed by minimal or no antiplatelet effect, and higher risk of treatment failure. In combination with other known risk factors, CYP2C19 genetic testing could be very valuable in predicting low clopidogrel efficacy. At the same time, it could be very successful in selecting patients who will most probably benefit from the clopidogrel-based therapy, thus decreasing the pool of those who might need more expensive and otherwise riskier antiplatelet alternatives.
Collapse
Affiliation(s)
- Natasa Djordjevic
- Faculty of Medical Sciences, Department of Pharmacology and Toxicology, University of Kragujevac, Svetozara Markovica 69, 34 000 Kragujevac, Serbia
| |
Collapse
|
4
|
Mugosa S, Todorovic Z, Cukic J, Sahman-Zaimovic M, Djordjevic N. ABCB1 polymorphism in clopidogrel-treated Montenegrin patients. Open Life Sci 2021; 16:142-149. [PMID: 33817306 PMCID: PMC7968540 DOI: 10.1515/biol-2021-0017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/12/2021] [Accepted: 01/12/2021] [Indexed: 12/21/2022] Open
Abstract
Clopidogrel is an antiplatelet drug that displays significant interindividual variability in treatment response. Its bioavailability depends on the function of P-glycoprotein (P-gp), which is coded by a highly polymorphic ABCB1 gene. Thus, the aim of this study was to investigate the effect of ABCB1 genetic polymorphism on clopidogrel efficacy and safety and to determine the frequency distribution of its most common single nucleotide polymorphisms (SNPs) in 106 Montenegrin cardiology patients. Clopidogrel efficacy and safety were followed up during 1 year after hospitalization, with the lack of efficacy and adverse drug reactions observed in 11 (10.4%) and 8 patients (7.5%), respectively. Genotyping for ABCB1 SNPs rs1128503 (1236C > T), rs2032582 (2677G > A/T), and rs1045642 (3435C > T) was performed by the real-time PCR method, and the variant alleles were detected with the frequencies of 42.9, 44.8, and 52.8%, respectively. No significant association was observed between any of the examined genotypes and clopidogrel efficacy (p = 0.253) or safety (p = 0.424). Due to small sample size, co-treatment with other drugs, and other genetic factors not taken into account, we believe the absence of correlation between ABCB1 genotypes and indicators of clopidogrel efficacy and safety in this study should be apprehended conditionally, and that larger and better-controlled studies are warranted.
Collapse
Affiliation(s)
- Snezana Mugosa
- Faculty of Medicine, Department of Pharmacology, University of Montenegro, 81104 Podgorica, Montenegro.,Institute for Medicines and Medical Devices of Montenegro, 81104 Podgorica, Montenegro
| | - Zoran Todorovic
- Department of Pharmacology, Clinical Pharmacology Toxicology, Faculty of Medicine, University of Belgrade, University Medical Center "Bežanijska kosa", 11000 Belgrade, Serbia
| | - Jelena Cukic
- Department for Immunology and Virology, Public Health Institute, 34000 Kragujevac, Serbia
| | - Majda Sahman-Zaimovic
- Faculty of Medicine, Department of Pharmacology, University of Montenegro, 81104 Podgorica, Montenegro.,Institute for Medicines and Medical Devices of Montenegro, 81104 Podgorica, Montenegro
| | - Natasa Djordjevic
- Department of Pharmacology and Toxicology, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34000 Kragujevac, Serbia
| |
Collapse
|
5
|
Xi D, Jiang W, Shao Y, Song X, Chen Y, Liu M, Gu W, Li Q. Retrospective analysis of the bleeding risk induced by oral antiplatelet drugs during radiotherapy. Medicine (Baltimore) 2021; 100:e24580. [PMID: 33578556 PMCID: PMC7886460 DOI: 10.1097/md.0000000000024580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 01/14/2021] [Indexed: 01/05/2023] Open
Abstract
We conducted this retrospective analysis to assess whether oral antiplatelet drugs (APDs) during radiotherapy increase bleeding risk.Patients who underwent radiotherapy for esophageal cancer (EC) in the Third Affiliated Hospital of Soochow University from January 2015 to December 2019 were screened. After the differences in clinical parameters were eliminated by a propensity-score matched (PSM) analysis at a 1:1 ratio, the thrombocytopenia, consumption of platelet-increasing drugs, suspension of radiotherapy, and bleeding in patients taking APDs were compared with those in the control group.A total of 986 patients were included in the original dataset. Of these, 34 patients took APDs during radiotherapy. After matching, the APD and control groups each retained 31 patients. There was no significant difference in platelet concentrations between the two groups before radiotherapy (P = .524). The lowest platelet concentration during radiotherapy in the APD group was significantly lower (P = .033). The consumption of platelet-increasing drugs in the APD group was higher than that in the control group (P < .05). However, there was no significant difference in the average number of days of radiotherapy suspension because of thrombocytopenia (P = .933) and no significant difference in the incidence of bleeding between the two groups (P = .605).Oral APDs during radiotherapy lead to a further decrease in platelet concentration, but timely and adequate application of platelet-increasing drugs can avoid the increased risk of bleeding and the reduced efficacy of radiotherapy.
Collapse
|
6
|
Ye Y, Wan W, Wang J, Hu W, Wang H, Li L, Sang P, Gu Y, Li D, Wang Z, Meng Z. The CEACAM1-derived peptide QLSN impairs collagen-induced human platelet activation through glycoprotein VI. Biosci Biotechnol Biochem 2019; 84:85-94. [PMID: 31794329 DOI: 10.1080/09168451.2019.1662277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) regulates collagen-mediated platelet activation through its cytoplasmic immunoreceptor tyrosine-based inhibition motifs (ITIMs). However, the function of CEACAM1's extracellular cleavage fragments is currently unknown. In the present study, we used mass spectrometry (MS) to identify 9 cleavage fragments shed by matrix metallopeptidase 12 (MMP-12), and then we synthesized peptides with sequences corresponding to the fragments. QLSNGNRTLT (QLSN), a peptide from the A1-domain of CEACAM1, significantly attenuated collagen-induced platelet aggregation. QLSN also attenuated platelet static adhesion to collagen. Additionally, QLSN reduced human platelet secretion and integrin αIIbβ3 activation in response to glycoprotein VI (GPVI)-selective agonist, convulxin. Correspondingly, QLSN treatment significantly decreased convulxin-mediated phosphorylation of Src, protein kinase B (Akt), spleen tyrosine kinase (Syk) and phospholipase Cγ2 (PLCγ2) in human platelets. These data indicate that the CEACAM1-derived peptide QLSN inhibits GPVI-mediated human platelet activation. QLSN could potentially be developed as a novel antiplatelet agent.
Collapse
Affiliation(s)
- Yujia Ye
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Wen Wan
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Jing Wang
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Wei Hu
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Huawei Wang
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Longjun Li
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Peng Sang
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Yajuan Gu
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Deng Li
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Zhe Wang
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| | - Zhaohui Meng
- Laboratory of Molecular Cardiology, Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, PR China
| |
Collapse
|
7
|
Abstract
Patients affected by cardiovascular disease (CVD) are treated with antiplatelet agents (AA) and/or anticoagulant drugs, which are fundamental in the management of stroke, coronary atherosclerotic disease, peripheral vascular disease and atrial fibrillation. CVD is the most important cause of death in chronic renal failure (CRF). Death rates from myocardial infarction (MI) and from all other cardiac causes exceed those for the general population. Incidence of MI in CRF is triple that in the general population. Moreover, mortality is seven- to eight-fold higher in patients requiring chronic hemodialysis compared to the general population, and approximately 40% of deaths in this population are attributable to coronary artery disease (CAD). For these reasons, AA are widely used in patients affected by CRF. Current data do not support a protective effect of antiplatelet administration in hemodialytic patients as primary prevention of cardiovascular mortality. Different results have been obtained concerning secondary prevention of CVD. The Cooperative Cardiovascular Project demonstrated that dialysis patients treated with aspirin following MI had a 43% lower mortality. Another study reported that the use of aspirin and beta-blockers following MI was associated with lower mortality in CRF patients. However, aspirin plus clopidogrel seems to increase the hemorrhagic risk without a significant reduction in cardiovascular mortality and there are insufficient data to support the use of new AA drugs in hemodialytic patients. In conclusion, since CRF patients are one of the groups at highest risk for atherosclerotic events, it could be reasonable to use aspirin in HD patients. However, the bleeding risk in HD patients needs to be strongly evaluated, especially before starting dual AA treatment.
Collapse
|
8
|
Mohan IV, Mikhailidis DP, Stansby GP. Platelet Activation in Bypass Surgery for Critical Limb Ischemia. Vasc Endovascular Surg 2016; 41:322-9. [PMID: 17704335 DOI: 10.1177/1538574407302753] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Platelet activation contributes to graft occlusion after bypass surgery. This study investigated platelet activation status before, during, and after bypass. Blood was taken preoperatively from patients undergoing femoro-popliteal bypass and at incision, after dissection, after ischemia, after reperfusion, 24 hours after surgery, and almost 2 years after bypass (and given aspirin or warfarin). Platelet aggregation was measured using a turbidimetric method and platelet activation with flow cytometry. Statistical analysis was performed using Mann-Whitney U and Wilcoxon's tests. Resting platelet activation was similar between controls and patients undergoing bypass. Platelet activation decreased at incision but remained highly reactive. Platelet aggregation increased after dissection and the ischemic phase but significantly decreased after reperfusion. Platelet aggregation and activation were increased at 24 hours and subsequently after bypass. Platelets in critical limb ischemia exist in the primed state and become activated by minimum stimuli. Increased platelet activation occurs after bypass grafting for critical limb ischemia despite adjunctive therapy.
Collapse
Affiliation(s)
- Irwin V Mohan
- Academic Surgical Unit, St. Mary's Hospital, London, United Kingdom.
| | | | | |
Collapse
|
9
|
Computational fluid dynamics characterization of blood flow in central aorta to pulmonary artery connections: importance of shunt angulation as a determinant of shear stress-induced thrombosis. Pediatr Cardiol 2015; 36:600-15. [PMID: 25404555 DOI: 10.1007/s00246-014-1055-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/31/2014] [Indexed: 10/24/2022]
Abstract
The central aortic shunt, consisting of a Gore-Tex (polytetrafluoroethylene) tube (graft) connecting the ascending aorta to the pulmonary artery, is a palliative operation for neonates with cyanotic congenital heart disease. These tubes often have an extended length, and therefore must be angulated to complete the connection to the posterior pulmonary arteries. Thrombosis of the graft is not uncommon and can be life-threatening. We have shown that a viscous fluid (such as blood) traversing a curve or bend in a small-caliber vessel or conduit can give rise to marked increases in wall shear stress, which is the major mechanical factor responsible for vascular thrombosis. Thus, the objective of this study was to use computational fluid dynamics to investigate whether wall shear stress (and shear rate) generated in angulated central aorta-to-pulmonary artery connections, in vivo, can be of magnitude and distribution to initiate platelet activation/aggregation, ultimately leading to thrombus formation. Anatomical features required to construct the computer-simulated blood flow pathways were verified from angiograms of central aortic shunts in patients. For the modeled central aortic shunts, we found wall shear stresses of (80-200 N/m(2)), with shear rates of (16,000-40,000/s), at sites of even modest curvature, to be high enough to cause platelet-mediated shunt thrombosis. The corresponding energy losses for the fluid transitions through the aorta-to-pulmonary connections constituted (70 %) of the incoming flow's mechanical energy. The associated velocity fields within these shunts exhibited vortices, eddies, and flow stagnation/recirculation, which are thrombogenic in nature and conducive to energy dissipation. Angulation-induced, shear stress-mediated shunt thrombosis is insensitive to aspirin therapy alone. Thus, for patients with central aortic shunts of longer length and with angulation, aspirin alone will provide insufficient protection against clotting. These patients are at risk for shunt thrombosis and significant morbidity and mortality, unless their anticoagulation regimen includes additional antiplatelet medications.
Collapse
|
10
|
Willerson JT, Ferguson JJ, Patel DD. Medical Treatment of Stable Angina. Coron Artery Dis 2015. [DOI: 10.1007/978-1-4471-2828-1_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Boldron C, Besse A, Bordes MF, Tissandié S, Yvon X, Gau B, Badorc A, Rousseaux T, Barré G, Meneyrol J, Zech G, Nazare M, Fossey V, Pflieger AM, Bonnet-Lignon S, Millet L, Briot C, Dol F, Hérault JP, Savi P, Lassalle G, Delesque N, Herbert JM, Bono F. N-[6-(4-butanoyl-5-methyl-1H-pyrazol-1-yl)pyridazin-3-yl]-5-chloro-1-[2-(4-methylpiperazin-1-yl)-2-oxoethyl]-1H-indole-3-carboxamide (SAR216471), a novel intravenous and oral, reversible, and directly acting P2Y12 antagonist. J Med Chem 2014; 57:7293-316. [PMID: 25075638 DOI: 10.1021/jm500588w] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In the search of a potential backup for clopidogrel, we have initiated a HTS campaign designed to identify novel reversible P2Y12 antagonists. Starting from a hit with low micromolar binding activity, we report here the main steps of the optimization process leading to the identification of the preclinical candidate SAR216471. It is a potent, highly selective, and reversible P2Y12 receptor antagonist and by far the most potent inhibitor of ADP-induced platelet aggregation among the P2Y12 antagonists described in the literature. SAR216471 displays potent in vivo antiplatelet and antithrombotic activities and has the potential to differentiate from other antiplatelet agents.
Collapse
|
12
|
P2Y(12) receptor on the verge of a neuroinflammatory breakdown. Mediators Inflamm 2014; 2014:975849. [PMID: 25180027 PMCID: PMC4142314 DOI: 10.1155/2014/975849] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/25/2014] [Accepted: 06/26/2014] [Indexed: 12/22/2022] Open
Abstract
In the CNS, neuroinflammation occurring during pathologies as amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) is the consequence of an intricate interplay orchestrated by various cell phenotypes. Among the molecular cues having a role in this process, extracellular nucleotides are responsible for intercellular communication and propagation of inflammatory stimuli. This occurs by binding to several receptor subtypes, defined P2X/P2Y, which are widespread in different tissues and simultaneously localized on multiple cells. For instance, the metabotropic P2Y12 subtype is found in the CNS on microglia, affecting activation and chemotaxis, on oligodendrocytes, possessing a hypothesized role in myelination, and on astrocytes. By comparative analysis, we have established here that P2Y12 receptor immunolabelled by antibodies against C-terminus or second intracellular loop, is, respectively, distributed and modulated under neuroinflammatory conditions on ramified microglia or myelinated fibers, in primary organotypic cerebellar cultures, tissue slices from rat striatum and cerebellum, spinal cord sections from symptomatic/end stage SOD1-G93A ALS mice, and finally autoptic cortical tissue from progressive MS donors. We suggest that modulation of P2Y12 expression might play a dual role as analytic marker of branched/surveillant microglia and demyelinating lesions, thus potentially acquiring a predictive value under neuroinflammatory conditions as those found in ALS and MS.
Collapse
|
13
|
Abstract
Stroke is the third leading cause of death and the leading cause of disability in the developed world. Atherothrombosis is the underlying condition that results in events leading to ischemic stroke and vascular death. Antiplatelet therapy is commonly used for both acute stroke and in secondary prevention. Numerous trials and meta-analyses have left little doubt that antiplatelet therapy effectively reduces stroke risk in patients with prior stroke or transient ischemic attack. Current antiplatelet agents include acetylsalicylic acid, clopidogrel, ticlopidine and extended release dipyridamole with low doses of acetylsalicyclic acid (aspirin). The optimum doses of antiplatelet drugs depend upon several variables, such as genetic and environmental factors, so that clinical and laboratory response for dosage varies for each patient. Recently, the correlation between the laboratory-measurable effect of antiplatelet agents and the clinical effectiveness on the mortality of ischemic stroke and cardiovascular patients has been documented. Due to the side effect of bleeding with different antithrombotic drugs, their future employment will be determined in combination with low dosages of each component. Laboratory-controlled, tailored drug therapy will be needed for long-lasting secondary prevention of ischemic stroke.
Collapse
Affiliation(s)
- Endre Pongrácz
- Department of Neurology, Central Hospital, Ministry of Interior Budapest, H-1071 Budapest, Városligeti fasor 9-13, Hungary.
| | | |
Collapse
|
14
|
Anderson JL, Adams CD, Antman EM, Bridges CR, Califf RM, Casey DE, Chavey WE, Fesmire FM, Hochman JS, Levin TN, Lincoff AM, Peterson ED, Theroux P, Wenger NK, Wright RS, Zoghbi WA, Arend TE, Oetgen WJ, May C, Bradfield L, Keller S, Ramadhan E, Tomaselli GF, Brown N, Robertson RM, Whitman GR, Bezanson JL, Hundley J. 2012 ACCF/AHA Focused Update Incorporated Into the ACCF/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction. Circulation 2013; 127:e663-828. [DOI: 10.1161/cir.0b013e31828478ac] [Citation(s) in RCA: 181] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
15
|
Anderson JL, Adams CD, Antman EM, Bridges CR, Califf RM, Casey DE, Chavey WE, Fesmire FM, Hochman JS, Levin TN, Lincoff AM, Peterson ED, Theroux P, Wenger NK, Wright RS, Jneid H, Ettinger SM, Ganiats TG, Philippides GJ, Jacobs AK, Halperin JL, Albert NM, Creager MA, DeMets D, Guyton RA, Kushner FG, Ohman EM, Stevenson W, Yancy CW. 2012 ACCF/AHA focused update incorporated into the ACCF/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013; 61:e179-347. [PMID: 23639841 DOI: 10.1016/j.jacc.2013.01.014] [Citation(s) in RCA: 373] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
16
|
Abstract
Antiplatelet therapy remains the mainstay in preventing aberrant platelet activation in pathophysiological conditions such as myocardial infarction, ischemia, and stroke. Although there has been significant advancement in antiplatelet therapeutic approaches, aspirin still remains the gold standard treatment in the clinical setting. Limitations in safety, efficacy, and tolerability have precluded many of the antiplatelet inhibitors from use in patients. Unforeseen incidences of increased bleeding risk and recurrent arterial thrombosis observed in patients have hampered the development of superior next generation antiplatelet therapies. The pharmacokinetic and pharmacodynamic profiles have also limited the effectiveness of a number of antiplatelet inhibitors currently in use due to variability in metabolism, time to onset, and reversibility. A focused effort in the development of newer antiplatelet therapies to address some of these shortcomings has resulted in a significant number of potential antiplatelet drugs which target enzymes (phosphodiesterase, cyclooxygenase), receptors (purinergic, prostaglandins, protease-activated receptors, thromboxane), and glycoproteins (αIIbβ3, GPVI, vWF, GPIb) in the platelet. The validation and search for newer antiplatelet therapeutic approaches proven to be superior to aspirin is still ongoing and should yield a better pharmacodynamic profile with fewer untoward side-effects to what is currently in use today.
Collapse
Affiliation(s)
- Jennifer Yeung
- Cardeza Foundation for Hematologic Research, Department of Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | | |
Collapse
|
17
|
Puymirat E, Aïssaoui N, Coste P, Dentan G, Bataille V, Drouet E, Mulak G, Carrié D, Blanchard D, Simon T, Danchin N. Comparison of efficacy and safety of a standard versus a loading dose of clopidogrel for acute myocardial infarction in patients ≥ 75 years of age (from the FAST-MI registry). Am J Cardiol 2011; 108:755-9. [PMID: 21726837 DOI: 10.1016/j.amjcard.2011.04.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 04/29/2011] [Accepted: 04/29/2011] [Indexed: 01/05/2023]
Abstract
Data are lacking on the efficacy and safety of a loading dose (LD) of clopidogrel in elderly patients with acute myocardial infarction (AMI). FAST-MI is a nationwide registry that was carried out over a 1-month period in 2005 and included consecutive patients with AMI admitted to intensive care units <48 hours from symptom onset in 223 participating centers. We assessed the impact of a clopidogrel LD (≥300 mg) compared to a conventional dose (<300 mg) on bleeding, need for blood transfusion, and 30-day and 12-month survivals in 791 elderly patients (≥75 years old, mean age 81 ± 4 years, 48% women, 35% with ST-segment elevation MI) included in this registry. Fifty-nine percent (466 patients) received a clopidogrel LD. Follow-up was >99% complete. Major bleeding and blood transfusions were not significantly different in patients who received a clopidogrel LD (3.2% vs 3.7%, p = 0.72; 5.4% vs 6.2%, p = 0.64, respectively). Early mortality was also not significantly different (10.1 vs 10.8, p = 0.76). Using multivariate analyses, clopidogrel LD did not significantly affect major bleeding or transfusion (odds ratio 1.03, 95% confidence interval 0.49 to 2.17, p = 0.94) and 12-month mortality (hazard ratio 1.00, 95% confidence interval 0.72 to 1.40, p = 0.98). In conclusion, the present data showed that in elderly patients admitted for AMI, use of a LD of clopidogrel compared to a conventional dose was not associated with increased in-hospital bleeding, need for transfusion, or mortality. Large-scale randomized trials are still needed to identify the optimal LD of clopidogrel for elderly patients admitted for AMI.
Collapse
Affiliation(s)
- Etienne Puymirat
- Division of Coronary Artery Disease and Intensive Cardiac Care, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Wright RS, Anderson JL, Adams CD, Bridges CR, Casey DE, Ettinger SM, Fesmire FM, Ganiats TG, Jneid H, Lincoff AM, Peterson ED, Philippides GJ, Theroux P, Wenger NK, Zidar JP, Anderson JL, Adams CD, Antman EM, Bridges CR, Califf RM, Casey DE, Chavey WE, Fesmire FM, Hochman JS, Levin TN, Lincoff AM, Peterson ED, Theroux P, Wenger NK, Zidar JP. 2011 ACCF/AHA focused update incorporated into the ACC/AHA 2007 Guidelines for the Management of Patients with Unstable Angina/Non-ST-Elevation Myocardial Infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines developed in collaboration with the American Academy of Family Physicians, Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons. J Am Coll Cardiol 2011; 57:e215-367. [PMID: 21545940 DOI: 10.1016/j.jacc.2011.02.011] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
19
|
Anderson JL, Adams CD, Antman EM, Bridges CR, Califf RM, Casey DE, Chavey WE, Fesmire FM, Hochman JS, Levin TN, Lincoff AM, Peterson ED, Theroux P, Wenger NK, Wright RS, Smith SC. 2011 ACCF/AHA Focused Update Incorporated Into the ACC/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation 2011; 123:e426-579. [PMID: 21444888 DOI: 10.1161/cir.0b013e318212bb8b] [Citation(s) in RCA: 349] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
20
|
|
21
|
El-Sadek MEH, Moustafa SM, Kadi HO, Al-Hakami AMA. Determination of Clopidogrel Carboxylic Acid in Human Plasma by LC-MS/MS. ACTA ACUST UNITED AC 2011. [DOI: 10.4236/ajac.2011.24054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
22
|
De Caterina R, Kristensen SD, Renda G. New anticoagulants for atrial fibrillation. J Cardiovasc Med (Hagerstown) 2009; 10:446-53. [PMID: 19365276 DOI: 10.2459/jcm.0b013e3283249aee] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Although warfarin and other vitamin K antagonists have clearly the greatest efficacy among treatments commonly available in preventing stroke in atrial fibrillation, their use is associated with a substantial risk of major bleedings and are unpractical and difficult to use because of their narrow therapeutic window, their interaction with drugs and foods, and the need of frequent coagulation monitoring. Several new anticoagulants are now undergoing phase III clinical trials in atrial fibrillation with the aim of demonstrating noninferiority compared with vitamin K antagonists or superiority compared with aspirin in patients in whom vitamin K antagonists are contraindicated or not tolerated. These drugs fall in different pharmacological categories of oral direct thrombin inhibitors, parenteral long-lived indirect factor Xa inhibitors, and oral direct factor Xa inhibitors. Cardiologists need to be aware of the explosive pharmacological literature being accrued with these new drugs, as most of these will likely enter the clinical arena in the near future.
Collapse
Affiliation(s)
- Raffaele De Caterina
- Institute of Cardiology and Center of Excellence on Aging, 'G. d'Annunzio' University - Chieti, Italy.
| | | | | |
Collapse
|
23
|
Ramana RK, Lewis BE. Percutaneous coronary intervention in patients with acute coronary syndrome: focus on bivalirudin. Vasc Health Risk Manag 2008; 4:493-505. [PMID: 18827868 PMCID: PMC2515410 DOI: 10.2147/vhrm.s2455] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Previously, indirect thrombin inhibitors such as unfractionated heparin or low-molecular-weight heparin were used as a standard anticoagulation during percutaneous coronary intervention to prevent procedural thrombotic complications but at a risk of hemorrhagic complications. More recently, bivalirudin, a member of the direct thrombin inhibitor class, has been shown to have 1) predictable pharmacokinetics, 2) ability to inhibit free- and clot-bound thrombin, 3) no properties of platelet activation, 4) avoidance of heparin-induced thrombocytopenia, and 5) a significant reduction of bleeding without a reduction in thrombotic or ischemic endpoints compared to heparin and glycoprotein IIbIIIa inhibitors when used in patients presenting with acute coronary syndrome who are planned for an invasive treatment strategy.
Collapse
Affiliation(s)
- Ravi K Ramana
- Division of Cardiology, Loyola University Medical Center, Maywood, Illinois 60647, USA.
| | | |
Collapse
|
24
|
Heptinstall S. Editorial: Cardiovascular & Renal: Numerous approaches to reducing platelet aggregation. Expert Opin Investig Drugs 2008. [DOI: 10.1517/13543784.4.11.1027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
25
|
Douglass JG, deCamp JB, Fulcher EH, Jones W, Mahanty S, Morgan A, Smirnov D, Boyer JL, Watson PS. Adenosine analogues as inhibitors of P2Y12 receptor mediated platelet aggregation. Bioorg Med Chem Lett 2008; 18:2167-71. [PMID: 18276138 DOI: 10.1016/j.bmcl.2008.01.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 01/08/2008] [Accepted: 01/10/2008] [Indexed: 10/22/2022]
Abstract
Modified adenosine derivatives may lead to the development of P2Y(12) antagonists that are potent, selective, and bind reversibly to the receptor. Analogues of 2',3'-trans-styryl acetal-N6-ureido-adenosine monophosphate were prepared by modification of the 5'-position. The resulting analogues were tested for P2Y(12) antagonism in a platelet aggregation assay.
Collapse
Affiliation(s)
- James G Douglass
- Inspire Pharmaceuticals, Inc., Department of Medicinal Chemistry, 4222 Emperor Boulevard, Suite 200, Durham, NC 27703, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Anderson JL, Adams CD, Antman EM, Bridges CR, Califf RM, Casey DE, Chavey WE, Fesmire FM, Hochman JS, Levin TN, Lincoff AM, Peterson ED, Theroux P, Wenger NK, Wright RS, Smith SC, Jacobs AK, Adams CD, Anderson JL, Antman EM, Halperin JL, Hunt SA, Krumholz HM, Kushner FG, Lytle BW, Nishimura R, Ornato JP, Page RL, Riegel B. ACC/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-Elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction) developed in collaboration with the American College of Emergency Physicians, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation and the Society for Academic Emergency Medicine. J Am Coll Cardiol 2007; 50:e1-e157. [PMID: 17692738 DOI: 10.1016/j.jacc.2007.02.013] [Citation(s) in RCA: 1285] [Impact Index Per Article: 75.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
27
|
Hourani SM, Hall DA. P2T purinoceptors: ADP receptors on platelets. CIBA FOUNDATION SYMPOSIUM 2007; 198:53-64; discussion 64-70. [PMID: 8879818 DOI: 10.1002/9780470514900.ch3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
ADP acts on platelets via the P2T purinoceptor to cause aggregation, but the way in which it does so is not fully understood. Most aggregating agents act via G protein-coupled receptors to stimulate phospholipase C (PLC) and so mobilize Ca2+ via inositol trisphosphate, whereas ADP clearly causes the mobilization of Ca2+ from internal stores but is only a weak activator of PLC. ADP also inhibits adenylate cyclase and it has been suggested that this effect is mediated by a different receptor, although evidence from antagonist studies argues against this. Studies of Ca2+ influx have shown that ADP is unique in causing a rapid influx of Ca2+, and patch-clamp studies have confirmed the activation by ADP of non-selective cation channels. This would imply the existence of two ADP receptors on platelets, a receptor-operated channel responsible for the rapid Ca2+ influx and a G protein-coupled receptor possibly linked to both inhibition of adenylate cyclase and mobilization of Ca2+. In this review the structure-activity relationships for aggregation, inhibition of adenylate cyclase and increases in cytoplasmic Ca2+ are summarized, and the relationship between these effects discussed.
Collapse
Affiliation(s)
- S M Hourani
- Receptors and Cellular Regulation Research Group, School of Biological Sciences, University of Surrey, Guildford, UK
| | | |
Collapse
|
28
|
Anderson JL, Adams CD, Antman EM, Bridges CR, Califf RM, Casey DE, Chavey WE, Fesmire FM, Hochman JS, Levin TN, Lincoff AM, Peterson ED, Theroux P, Wenger NK, Wright RS, Smith SC, Jacobs AK, Halperin JL, Hunt SA, Krumholz HM, Kushner FG, Lytle BW, Nishimura R, Ornato JP, Page RL, Riegel B. ACC/AHA 2007 guidelines for the management of patients with unstable angina/non ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non ST-Elevation Myocardial Infarction): developed in collaboration with the American College of Emergency Physicians, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons: endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation and the Society for Academic Emergency Medicine. Circulation 2007; 116:e148-304. [PMID: 17679616 DOI: 10.1161/circulationaha.107.181940] [Citation(s) in RCA: 813] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
29
|
Ferguson JJ, Patel DD, Willerson JT. Medical Treatment of Stable Angina. CARDIOVASCULAR MEDICINE 2007. [DOI: 10.1007/978-1-84628-715-2_41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
30
|
Greenbaum AB, Grines CL, Bittl JA, Becker RC, Kereiakes DJ, Gilchrist IC, Clegg J, Stankowski JE, Grogan DR, Harrington RA, Emanuelsson H, Weaver WD. Initial experience with an intravenous P2Y12 platelet receptor antagonist in patients undergoing percutaneous coronary intervention: results from a 2-part, phase II, multicenter, randomized, placebo- and active-controlled trial. Am Heart J 2006; 151:689.e1-689.e10. [PMID: 16504633 DOI: 10.1016/j.ahj.2005.11.014] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Accepted: 11/30/2005] [Indexed: 11/17/2022]
Abstract
BACKGROUND Platelet-initiated acute thrombosis and coronary embolization are fundamental in the pathophysiology of complications during percutaneous coronary intervention (PCI). Cangrelor (formerly AR-C69931MX) is a novel, rapidly acting, intravenous, specific antagonist of platelet aggregation via binding to the adenosine diphosphate (ADP) P2Y12 receptor subtype. The primary aims of this study were to assess the initial safety and pharmacodynamics of cangrelor in patients undergoing PCI. METHODS In part 1, patients undergoing PCI were randomized to an 18- to 24-hour of either placebo, 1-, 2-, or 4-microg/kg per minute cangrelor in addition to aspirin and heparin beginning before PCI. In part 2, patients were randomized to receive either cangrelor (4 microg/kg per minute) or abciximab before PCI. The primary end point was the composite incidence of major and minor bleeding through 7 days. Secondary end points included the occurrence of major adverse coronary events (death, MI, and unplanned repeat coronary intervention) through 30 days plus ex vivo platelet aggregation and bleeding times. RESULTS Two hundred patients (3 dosage groups and placebo) were studied in part 1, and 199 additional patients were then randomized in the second part, comparing 1 dose of cangrelor and abciximab. Combined major and minor bleeding occurred in 13% of those receiving cangrelor and in 8% in those randomized to placebo (P = non significant [NS]) during part 1 and in 7% receiving cangrelor compared with 10% randomized to abciximab (P = NS), during part 2. The 30-day composite incidence of adverse cardiac events was similar between those receiving cangrelor and those receiving abciximab during part 2 (7.6% vs 5.3%, respectively, P = NS). Mean inhibition of ex vivo platelet aggregation in response to 3 micromol/L ADP at steady state was 100% for both cangrelor 4 microg/kg per minute and abciximab groups in part 2. After termination of infusion, platelet aggregation returned to baseline response more rapidly with cangrelor compared with abciximab. There was a trend toward longer bleeding time prolongation and lower platelet count with abciximab compared with cangrelor. CONCLUSIONS This initial experience with intravenous cangrelor during PCI suggests an acceptable risk of bleeding and adverse cardiac events while achieving rapid, reversible inhibition of platelet aggregation via competitive binding to the ADP P2Y12 platelet receptor with less prolongation of bleeding time then the glycoprotein IIb/IIIa receptor antagonist abciximab.
Collapse
|
31
|
Hagiwara A, Matsuda T, Shimazaki S. Life-threatening subcutaneous hemorrhage following minor blunt trauma in an elderly patient taking ticlopidine and aspirin: a case report. Emerg Radiol 2005; 12:47-9. [PMID: 16311744 DOI: 10.1007/s10140-005-0446-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Accepted: 09/07/2005] [Indexed: 11/29/2022]
Abstract
We report a rare case in which life-threatening subcutaneous hemorrhage following minor blunt trauma developed in an elderly patient taking ticlopidine and aspirin. An 82-year-old woman taking ticlopidine and aspirin tripped on a road. She noted only mild pain at the left lower abdomen. However, the hematoma gradually enlarged, and she developed hemorrhagic shock. Emergently performed contrast-enhanced abdominal computed tomography showed a large hematoma (20 x 10 x 7 cm), including contrast extravasation, which was located beneath the skin of the left lower abdominal quadrant and within the external and internal oblique muscles. Emergency pelvic arteriography showed massive contrast extravasation from the left superficial iliac circumflex artery. Transcatheter arterial embolization (TAE) was successfully performed, using gelatin sponge pledgets and micro-size stainless steel coils. After TAE, hemodynamics stabilized. The patient was discharged uneventfully on day 12.
Collapse
Affiliation(s)
- Akiyoshi Hagiwara
- Department of Traumatology and Critical Care Medicine, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo, 181-8611, Japan.
| | | | | |
Collapse
|
32
|
|
33
|
|
34
|
Kerr JL, Oppelt TF, Rowen RC. Role of clopidogrel in unstable angina and non-ST-segment elevation myocardial infarction: from literature and guidelines to practice. Pharmacotherapy 2004; 24:1037-49. [PMID: 15338852 DOI: 10.1592/phco.24.11.1037.36135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Clinical trials are the backbone of treatment paradigm shifts and guideline development. In terms of acute coronary syndromes, the American College of Cardiology and the American Heart Association (ACC-AHA) have developed extensive guidelines to assist the practitioner in the appropriate use of drugs including antiischemic, anticoagulant, and antiplatelet agents. Clopidogrel, an adenosine 5'-diphosphate antagonist, is one such drug. Unfortunately, consensus guidelines are limited by the design of the clinical trials they reference. Clopidogrel trials have examined various outcomes in patients for a limited time frame, making longer term use of the drug difficult to justify. An ongoing study, estimated to be completed in 2005, is evaluating the long-term use of clopidogrel in high-risk patients. Aspirin, however, has become a lifelong therapy for many patients, based on clinical trials and medical experience. Patient-specific risk factors, the drugs' safety profiles, and costs, in addition to the ACC-AHA guidelines, must all be considered by clinicians when selecting the appropriate agent and its duration of use.
Collapse
Affiliation(s)
- Jessica L Kerr
- Department of Pharmacy Practice, College of Pharmacy, University of South Carolina, Columbia, South Carolina 29208, USA
| | | | | |
Collapse
|
35
|
Weksler BB. Antiplatelet Therapy for Secondary Prevention of Stroke. Stroke 2004. [DOI: 10.1016/b0-44-306600-0/50065-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
36
|
Oppelt TF, Bobadilla RV. Better living through chemistry: does it still apply to patients after myocardial infarction? Pharmacotherapy 2003; 23:816-22. [PMID: 12820824 DOI: 10.1592/phco.23.6.816.32176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Sudden cardiac death is an elusive process that claims a significant number of lives annually in the United States. It is often associated with increased mortality within the first year after myocardial infarction, with the highest frequency occurring among patients with left ventricular dysfunction. Therefore, increasing survival rates in patients with a history of both disorders is an important goal of therapy. Recent trials suggested that an implantable cardioverter-defibrillator (ICD) in these patients may be superior to medical intervention in reducing the high mortality rate. Four major trials measured the benefits of an ICD for patients at risk for life-threatening ventricular arrhythmias. We assessed whether patients in these trials received adequate drug therapy as directed by American College of Cardiology-American Heart Association guidelines. One aim was to determine if medicated patients who served as controls in the trials were fairly represented. Furthermore, the need for improved overall guideline adherence was apparent.
Collapse
Affiliation(s)
- Thomas F Oppelt
- Department of Pharmacy Practice, College of Pharmacy, University of South Carolina 700 Sumter Street, University of South Carolina, Columbia, SC 29208, USA
| | | |
Collapse
|
37
|
Wang K, Zhou X, Zhou Z, Tarakji K, Carneiro M, Penn MS, Murray D, Klein A, Humphries RG, Turner J, Thomas JD, Topol EJ, Lincoff AM. Blockade of the platelet P2Y12 receptor by AR-C69931MX sustains coronary artery recanalization and improves the myocardial tissue perfusion in a canine thrombosis model. Arterioscler Thromb Vasc Biol 2003; 23:357-62. [PMID: 12588784 DOI: 10.1161/01.atv.0000052669.50791.0b] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Reperfusion therapy for myocardial infarction is limited by a significant reocclusion rate and less optimal myocardial tissue perfusion due to excessive platelet accumulation and recruitment at the sites of vascular injury. We assessed the influence of a selective P2Y(12)-receptor antagonist (AR-C69931MX), in conjunction with thrombolytic therapy, on the prevention of platelet aggregation and thrombus formation. METHODS AND RESULTS A canine coronary electrolytic injury thrombosis model was used. Tissue-type plasminogen activator (t-PA; 1 mg/kg in phase I, 0.5 mg/kg in phase II in the AR-C69931MX group, and 1 mg/kg in the placebo group in phase I and II) was administered 30 minutes after thrombus formation; either saline or AR-C69931MX (4 micro g x kg(-1) x min(-1)) was given to all animals intravenously 10 minutes before t-PA administration for a total of 2 hours. All animals received heparin (80 U/kg) as an intravenous bolus followed by a continuous infusion of 17 U x kg(-1) x h(-1). Myocardial tissue perfusion was evaluated by use of the colored microsphere technique and real-time myocardial contrast echocardiography. The incidences of reocclusion and cyclic flow variation were significantly decreased in the AR-C69931MX group (P<0.05). Myocardial tissue flow with AR-C69931MX treatment improved significantly at 20 and 120 minutes after reflow, whereas tissue flow with placebo remained at a level similar to that during occlusion (P<0.05). CONCLUSIONS The adjunctive administration of AR-C69931MX blocked ADP-mediated platelet aggregation and recruitment and prevented platelet-mediated thrombosis, resulting in prolongation of reperfusion time and a decrease in reocclusion and cyclic flow variations. Importantly, myocardial tissue perfusion was significantly improved in the P2Y(12) antagonist group.
Collapse
Affiliation(s)
- Kai Wang
- Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
Emergency physicians are often the first clinicians to evaluate patients with acute atherothrombotic events. Platelet adenosine diphosphate (ADP) receptor antagonists, by specifically and irreversibly blocking ADP-induced platelet activation and aggregation, may reduce the injury associated with this process and can prevent recurrent ischemic events. Their role in the prevention of recurrent vascular events has been well documented. Recently, the CURE Trial showed that the combination of aspirin and clopidogrel improved outcomes in patients with non-ST-segment-elevation acute coronary syndrome (ACS). Familiarity with ADP receptor antagonists and knowledge about their appropriate use is important to the emergency physician in the management of ACS and potentially in that of transient ischemic attacks (TIAs), ischemic strokes, and acute peripheral arterial obstruction. This review addresses the pathophysiology of atherothrombosis and evaluates the potential use of ADP receptor antagonists in the Emergency Department setting.
Collapse
Affiliation(s)
- Charles V Pollack
- Department of Emergency Medicine, Pennsylvania Hospital, University of Pennsylvania Health System, Philadelphia, Pennsylvania 19107, USA
| |
Collapse
|
39
|
Abstract
Hemostasis involves a carefully regulated balance between circulating and endothelium-derived prothrombotic and antithrombotic factors. The unstable or vulnerable plaque facilitates thrombosis, clinically manifest as an acute coronary syndrome (ACS), by creating an environment that favors thrombus formation over prevention of lysis. Endothelial cell dysfunction is integral to both the development of the atherosclerotic lesion as well as its destabilization. The transformation of a stable plaque to an unstable one involves complex interactions among T lymphocytes, macrophages, endothelial cells, and smooth muscle cells. Degradation of the fibrous cap of the atherosclerotic lesion as well as the overexpression of prothrombotic and underexpression of antithrombotic factors by cells within the plaque precede thrombus formation. Accordingly, pharmacological interventions for the treatment of ACS are directed against the initiation and propagation of thrombosis, as well as toward improvement of endothelial function.
Collapse
Affiliation(s)
- Frederick L Ruberg
- Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118-2526, USA
| | | | | |
Collapse
|
40
|
Greco NJ, Tonon G, Chen W, Luo X, Dalal R, Jamieson GA. Novel structurally altered P(2X1) receptor is preferentially activated by adenosine diphosphate in platelets and megakaryocytic cells. Blood 2001; 98:100-7. [PMID: 11418468 DOI: 10.1182/blood.v98.1.100] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Experimental and clinical data suggest the presence of multiple types of adenosine diphosphate (ADP) receptors, one coupled to ligand-gated cation channels (P(2X)) and others coupled to G-protein-coupled (P(2Y)) receptors. This report identifies cDNA for a structurally altered P(2X1)-like receptor in megakaryocytic cell lines (Dami and CMK 11-5) and platelets that, when transfected into nonresponsive 1321 cells, confers a specific sensitivity to ADP with the pharmacologic rank order of ADP > > ATP > > > alpha,beta-methylene-ATP as measured by Ca(++) influx. This receptor (P(2X1del)) contains a deletion of 17 amino acids (PALLREAENFTLFIKNS) that includes an NFT consensus sequence for N-linked glycosylation. Glycosylated forms of the P(2X1del) and P(2X1wt) receptors were indistinguishable electrophoretically by Western blot or by immunoprecipitation using available antihuman and antirat antibodies. These results indicate that the expression of the P(2X1del) receptor results in an influx of Ca(++) induced by ADP. Expression of P(2X1del) receptor homomeric subunits is sufficient to express a receptor preferentially activated by ADP and suggests that this altered form, alone or in combination with P(2X1wt) receptors, is a component of an ADP-activated ion channel.
Collapse
MESH Headings
- Adenosine Diphosphate/pharmacology
- Blood Platelets/metabolism
- Calcium Signaling/drug effects
- Dose-Response Relationship, Drug
- Humans
- Megakaryocytes/metabolism
- Polymerase Chain Reaction
- Receptors, Purinergic/drug effects
- Receptors, Purinergic/genetics
- Receptors, Purinergic/metabolism
- Receptors, Purinergic P2/drug effects
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2X
- Sequence Homology, Nucleic Acid
- Transfection
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- N J Greco
- Platelet Biology and the Product Development Departments, American Red Cross, Rockville, MD, USA.
| | | | | | | | | | | |
Collapse
|
41
|
Léon C, Freund M, Ravanat C, Baurand A, Cazenave JP, Gachet C. Key role of the P2Y(1) receptor in tissue factor-induced thrombin-dependent acute thromboembolism: studies in P2Y(1)-knockout mice and mice treated with a P2Y(1) antagonist. Circulation 2001; 103:718-23. [PMID: 11156884 DOI: 10.1161/01.cir.103.5.718] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND ADP plays a key role in hemostasis, acting through 2 platelet receptors: the P2Y(1) receptor and an unidentified P2 receptor, called P2cyc, coupled to adenylyl cyclase inhibition, which is the target of the antiplatelet drug clopidogrel. We showed that the P2Y(1) receptor is an essential cofactor in thrombotic states induced by intravenous infusion of collagen and epinephrine. The aim of the present study was to assess the role of this receptor in thrombin-dependent tissue factor-induced thromboembolism. METHODS AND RESULTS Human thromboplastin was injected intravenously into wild-type or P2Y(1)-deficient mice, and the effects on platelet count and mortality were determined and plasma thrombin-antithrombin III (TAT) complexes were quantified. P2Y(1)-deficient mice were resistant to the thromboembolism induced by injection of thromboplastin. Whereas the platelet count decreased sharply in wild-type mice, there was no significant drop in platelets in P2Y(1)-knockout mice. The platelet consumption in wild-type mice was probably due to thrombin generation, because it was abolished by hirudin. Thromboplastin also led to a rise in TAT complexes in plasma, again reflecting thrombin formation. This effect, however, was less important in P2Y(1)-knockout mice than in wild-type mice, indicating that less thrombin was generated in the absence of P2Y(1). Similar results were obtained after intravenous administration of N:(6)-methyl-2'-deoxyadenosine-3':5'-bisphosphate, a selective antagonist of the P2Y(1) receptor, to wild-type mice. CONCLUSIONS Our results demonstrate a role of the P2Y(1) receptor in thrombotic states involving thrombin generation and provide further evidence for the potential relevance of this receptor as a target for antithrombotic drugs.
Collapse
Affiliation(s)
- C Léon
- Institut National de la Santé et de la Recherche Médicale U.311, Etablissement Français du Sang-Alsace, Strasbourg, France
| | | | | | | | | | | |
Collapse
|
42
|
Storey RF. Clinical experience with antithrombotic drugs acting on purine receptor pathways. Drug Dev Res 2001. [DOI: 10.1002/ddr.1117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
43
|
Affiliation(s)
- M R Jackson
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas 75235-9157, USA
| | | |
Collapse
|
44
|
Abstract
The contribution of platelets to the pathogenesis and progression of vascular complications in diabetes is supported by several studies. In general, platelets obtained from diabetic subjects show increased adhesiveness and an exaggerated aggregation, both spontaneous and in response to stimulating agents. The causes for this activation are multifold: altered exposure and/or abundance of glycoprotein receptors for agonists and adhesive proteins on the platelet surface, increased binding of fibrinogen, decreased membrane fluidity, altered platelet metabolism and changes in intraplatelet signalling pathways. The altered biophysical state of platelet membrane components in diabetes mellitus may be one of the major determinants of platelet hypersensitivity and hyperfunction and may contribute to impairments in various metabolic pathways, like intensified calcium mobilisation and accentuated thromboxane synthesis and release. Activated platelets interact with other cells, such as endothelial cells and leukocytes as well with the coagulation system in the process of atherosclerosis. Some studies indicated that platelet dysfunction was especially apparent in diabetic subjects with macro- or microangiopathy, while others showed that it may be related to the presence of diabetes mellitus per se. Several pharmaceutical compounds have been developed for the inhibition of platelet activation. However, aspirin treatment is cheap and effective, and aspirin remains to be the drug of choice for diabetic patients. It should be prescribed widely for patients who are at high risk of cardiovascular events.
Collapse
Affiliation(s)
- A B Sobol
- Laboratory of Haemostatic Disorders, Medical University of Lodz, 96 Narutowicz Street, 90 141 Lodz, Poland.
| | | |
Collapse
|
45
|
Braunwald E, Antman EM, Beasley JW, Califf RM, Cheitlin MD, Hochman JS, Jones RH, Kereiakes D, Kupersmith J, Levin TN, Pepine CJ, Schaeffer JW, Smith EE, Steward DE, Theroux P, Alpert JS, Eagle KA, Faxon DP, Fuster V, Gardner TJ, Gregoratos G, Russell RO, Smith SC. ACC/AHA guidelines for the management of patients with unstable angina and non-ST-segment elevation myocardial infarction. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients With Unstable Angina). J Am Coll Cardiol 2000; 36:970-1062. [PMID: 10987629 DOI: 10.1016/s0735-1097(00)00889-5] [Citation(s) in RCA: 559] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
46
|
Chinnakotla S, Leone JP, Fidler ME, Hammeke MD, Tarantolo S. Clopidogrel-associated thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in a kidney/pancreas transplant recipient. Transplantation 2000; 70:550-2. [PMID: 10949205 DOI: 10.1097/00007890-200008150-00029] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND We present a case report of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) developing in a kidney/pancreas transplant recipient after the initiation of treatment with clopidogrel for symptomatic coronary artery disease. METHODS A 35-year-old male kidney/pancreas recipient developed unstable angina 5 years after transplantation. The patient was treated with clopidogrel as adjunct therapy. A TTP/HUS condition developed, was diagnosed early, and successfully reversed with the implementation of plasmapheresis and cessation of clopidogrel and cyclosporine A. RESULTS The patient continues taking cyclosporine A with good renal function 6 months after the incident, and successfully underwent coronary artery by-pass grafting 3 months after the event. DISCUSSION This case demonstrates that early identification and treatment can reverse the TTP/HUS process associated with thienopyridine-derived agents. We strongly recommend that drugs of the thienopyridine class be used cautiously in transplant recipients, especially those taking calcineurin-inhibitors.
Collapse
Affiliation(s)
- S Chinnakotla
- Department of Solid Organ Transplantation, University of Nebraska Medical Center, Omaha 68198-3285, USA
| | | | | | | | | |
Collapse
|
47
|
Abstract
UNLABELLED Clopidogrel is an ADP receptor antagonist that is indicated for the reduction of atherosclerotic events including myocardial infarction, ischaemic stroke and vascular death in patients with atherosclerosis manifested by recent stroke, myocardial infarction or established peripheral vascular disease. In the 19 185 patients enrolled in the multicentre, randomised double-blind CAPRIE study, the annual risk of the combined end-point of ischaemic stroke, myocardial infarction and death from vascular disease (vascular death) was significantly lower during treatment with clopidogrel 75 mg/day than aspirin 325 mg/day [5.3 vs 5.8%/year, respectively; relative risk reduction (RRR) 8.7%, p = 0.043] after a mean follow-up of 1.9 years. Clopidogrel provided even greater reductions in the risk of recurrent ischaemic events than aspirin in patients with a history of coronary artery bypass surgery, diabetes mellitus and in those receiving concomitant lipid-lowering therapy. Moreover there was a significant reduction in the incidence of hospitalisation in patients treated with clopidogrel. In a patient population (Saskatchewan, Canada) with a greater risk of ischaemic events than the CAPRIE study population, the number of patients needed to be treated with clopidogrel to prevent 1 ischaemic event was estimated to be 70 (vs 200 in the CAPRIE study). In randomised trials and registry surveys, clopidogrel 75 mg/day plus aspirin had similar efficacy (as measured by adverse cardiac outcomes) to ticlopidine 250mg twice daily plus aspirin during the 30 days after placement of intracoronary stents. Tolerability of clopidogrel was significantly better than ticlopidine in the randomised, double-blind CLASSICS study. Among patients treated with clopidogrel or aspirin in the CAPRIE study, the overall gastrointestinal tolerability of clopidogrel was generally better than that of aspirin; the frequency of gastrointestinal haemorrhage was significantly lower among patients treated with clopidogrel than aspirin. Diarrhoea, rash and pruritus were significantly more common with clopidogrel than aspirin. CONCLUSION Clopidogrel was significantly more effective than aspirin in the prevention of vascular events (ischaemic stroke, myocardial infarction or vascular death) [corrected] in patients with atherothrombotic disease manifested by recent myocardial infarction, recent ischaemic stroke or symptomatic peripheral arterial occlusive disease [corrected] in the CAPRIE study. The overall tolerability profile of the drug was similar to that of aspirin, although gastrointestinal haemorrhage occurred significantly less often in clopidogrel recipients. The drug is widely used in combination with aspirin for the prevention of atherothrombosis after placement of intravascular stents, and available data suggest that this combination is as effective as ticlopidine plus aspirin for this indication.
Collapse
Affiliation(s)
- B Jarvis
- Adis International Limited, Mairangi Bay, Auckland, New Zealand.
| | | |
Collapse
|
48
|
Belcher PR, Muriithi EW, Milne EM, Wanikiat P, Wheatley DJ, Armstrong RA. Heparin, platelet aggregation, neutrophils, and cardiopulmonary bypass. Thromb Res 2000; 98:249-56. [PMID: 10822071 DOI: 10.1016/s0049-3848(99)00243-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
UNLABELLED Cardiopulmonary bypass (CPB) is associated with both neutrophil activation and failure of platelets to form large stable aggregates. We aimed to determine the effects of heparin and of neutrophil activation on platelet aggregation in whole blood. Fourteen patients undergoing routine aortocoronary bypass grafting and NSAID-free for over 7 days were studied before and after heparinisation, and at end-CPB. Whole blood, anticoagulated with rHirudin, was stirred for 3 minutes, and macroaggregation in response to collagen (0.6 microg. mL(-1)) or the neutrophil stimulant fMLP (10(-7)M) was determined by whole blood impedance aggregometry. Microaggregation was measured by counting unaggregated single platelets (corrected for haemodilution). The blood of volunteers was studied in vitro. PATIENTS Before CPB, heparin effectively abolished platelet macroaggregation induced by collagen (20.5 to 1.4 Ohms) or fMLP (3.9 to 0 Ohms (p<0.0001). CPB had no additional effect. Heparinisation also reduced the platelet count from 127 (110-170) to 95 (64-117). The inhibition of macroaggregation could not be reversed by ex vivo heparinase. VOLUNTEERS In vitro, the same heparin concentration, as measured in vivo (4 micromL(-1)), inhibited collagen-induced macroaggregation (20.3 to 14.7 Omega), but this effect was less than that observed ex vivo and was reversed by heparinase. In vitro heparin promoted fMLP macroaggregation (2.9 to 8.6 Omega). The inhibition of macroaggregation resulted from heparinisation, per se, rather than CPB and was insensitive to heparinase. There was less inhibition by in vitro heparin, which was reversible by heparinase, indicating a direct effect of heparin in vitro. The disparate findings are suggestive of an indirect action by heparin in vivo on macroaggregation, although heparin had a small direct stimulatory action on microaggregation.
Collapse
Affiliation(s)
- P R Belcher
- Department of Cardiac Surgery, University of Glasgow, Glasgow, United Kingdom.
| | | | | | | | | | | |
Collapse
|
49
|
Altomare C, Summo L, Cellamare S, Varlamov AV, Voskressensky LG, Borisova TN, Carotti A. Pyrrolo[3,2-c]pyridine derivatives as inhibitors of platelet aggregation. Bioorg Med Chem Lett 2000; 10:581-4. [PMID: 10741558 DOI: 10.1016/s0960-894x(00)00052-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A series of pyrrolo[3,2-c]pyridines, isosteres of the antithrombotic drug ticlopidine, has been synthesized and evaluated in vitro for the ability to inhibit aggregation of human platelet-rich plasma induced by adenosin 5'-diphosphate (ADP). Structure-activity relationships showed their antiplatelet effects to be related to the lipophilicity.
Collapse
Affiliation(s)
- C Altomare
- Dipartimento Farmacochimico, Università degli Studi, Bari, Italy.
| | | | | | | | | | | | | |
Collapse
|
50
|
Altman R, Scazziota A, Rouvier J, Gonzalez C. Effects of ticlopidine or ticlopidine plus aspirin on platelet aggregation and ATP release in normal volunteers: why aspirin improves ticlopidine antiplatelet activity. Clin Appl Thromb Hemost 1999; 5:243-6. [PMID: 10726021 DOI: 10.1177/107602969900500407] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aspirin and ticlopidine are used to prevent arterial thrombosis. In some clinical settings ticlopidine is administered with aspirin for improving antithrombotic effect. We administered aspirin (100 mg/day), ticlopidine (500 mg/day), or ticlopidine and aspirin for 7 days to healthy volunteers. Platelet aggregation and ATP release induced by sodium arachidonate, ADP, or a combination of both were measured. Sodium arachidonate (0.25 mmol/L), which produces no platelet aggregation, combined with adenosine diphosphate (1 mumol/L), which produced a reversible platelet aggregation of 20% after ticlopidine, resulted in a synergistic platelet aggregation response in normal (74.6 +/- 9.2%) and in ticlopidine platelet-rich plasma (59.1% +/- 14.9%, p < 0.0001). Synergism after sodium arachidonate (0.75 mmol/L) plus adenosine diphosphate (4 mumol/L) fell from 75.8% +/- 11.0% and 59.1% +/- 15.6% after ticlopidine or aspirin, respectively, to 14.8% +/- 18.0% (p < 0.0001) after ticlopidine plus aspirin. Aspirin and ticlopidine alone did not inhibit adenosine triphosphate release as thoroughly as did aspirin plus ticlopidine. Aspirin or ticlopidine does not adequately prevent platelet activity as ticlopidine plus aspirin do. Addition of aspirin to treatment with ticlopidine improves their antiplatelet activity and better results could be obtained in arterial thrombotic prevention strategies.
Collapse
Affiliation(s)
- R Altman
- Centro de Trombosis de Buenos Aires, Argentina
| | | | | | | |
Collapse
|