| 41. |
- Paré, Guillaume, et al.
(författare)
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Genetic Determinants of Dabigatran Plasma Levels and Their Relation to Bleeding
- 2013
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Ingår i: Circulation. - 0009-7322 .- 1524-4539. ; 127:13, s. 1404-
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundFixed-dose unmonitored treatment with dabigatran etexilate is effective and has a favorable safety profile in prevention of stroke in atrial fibrillation patients compared to warfarin. We hypothesized that genetic variants could contribute to inter-individual variability in blood concentrations of the active metabolite of dabigatran etexilate, and influence the safety and efficacy of dabigatran.Methods and ResultsWe successfully conducted a genome-wide association study in 2,944 RE-LY participants. The CES1 SNP rs2244613 was associated with trough concentrations, and the ABCB1 SNP rs4148738 and CES1 SNP rs8192935 were associated with peak concentrations at genome-wide significance (P<9 x 10-8) with a gene-dose effect. Each minor allele of the CES1 SNP rs2244613 was associated with lower trough concentrations (15% decrease per allele, 95%CI 10-19%; P=1.2 x 10-8) and a lower risk of any bleeding (OR=0.67, 95%CI 0.55-0.82; P=7 x 10-5) in dabigatran-treated participants, with a consistent but non-significant lower risk of major bleeding (OR=0.66, 95%CI 0.43-1.01). The interaction between treatment (warfarin versus all dabigatran) and carrier status was statistically significant (P=0.002) with carriers having less bleeding with dabigatran than warfarin (HR=0.59, 95%CI 0.46-0.76; P=5.2 x 10-5) in contrast to no difference in noncarriers (HR=0.96, 95%CI 0.81-1.14; P=0.65). There was no association with ischemic events, and neither rs4148738 nor rs8192935 was associated with bleeding or ischemic events.ConclusionsGenome-wide association analysis identified that carriage of CES1 rs2244613 minor allele occurred in 32.8% of patients in RELY and was associated with lower exposure to active dabigatran metabolite. The presence of the polymorphism was associated with a lower risk of bleeding.
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| 42. |
- Patrono, Carlo, et al.
(författare)
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Antiplatelet agents for the treatment and prevention of atherothrombosis
- 2011
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 32:23, s. 2922-32
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Forskningsöversikt (refereegranskat)abstract
- The clinical pharmacology of antiplatelet drugs has been reviewed previously by the European Society of Cardiology (ESC) Task force and by the 8th American College of Chest Physicians (ACCP) Evidence-Based Clinical Practice Guidelines. Moreover, information on the efficacy and safety of antiplatelet drugs in the treatment and prevention of atherothrombosis is provided by collaborative meta-analyses of 287 secondary prevention trials and 6 primary prevention trials. The present document intends to provide practicing physicians with an updated instrument to guide their choice of the most suitable antiplatelet strategy for the individual patient at risk, or with different clinical manifestations, of atherothrombosis.
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| 43. |
- Ringvall, Maria, et al.
(författare)
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Enhanced Platelet Activation Mediates the Accelerated Angiogenic Switch in Mice Lacking Histidine-Rich Glycoprotein
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:1, s. e14526-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The heparin-binding plasma protein histidine-rich glycoprotein (HRG; alternatively, HRGP/HPRG) can suppress tumor angiogenesis and growth in vitro and in vivo. Mice lacking the HRG gene are viable and fertile, but have an enhanced coagulation resulting in decreased bleeding times. In addition, the angiogenic switch is significantly enhanced in HRG-deficient mice. Methodology/Principal Findings: To address whether HRG deficiency affects tumor development, we have crossed HRG knockout mice with the RIP1-Tag2 mouse, a well established orthotopic model of multistage carcinogenesis. RIP1-Tag2 HRG(-/-) mice display significantly larger tumor volume compared to their RIP1-Tag2 HRG(+/+) littermates, supporting a role for HRG as an endogenous regulator of tumor growth. In the present study we also demonstrate that platelet activation is increased in mice lacking HRG. To address whether this elevated platelet activation contributes to the increased pathological angiogenesis in HRG-deficient mice, they were rendered thrombocytopenic before the onset of the angiogenic switch by injection of the anti-platelet antibody GP1b alpha. Interestingly, this treatment suppressed the increase in angiogenic neoplasias seen in HRG knockout mice. However, if GP1b alpha treatment was initiated at a later stage, after the onset of the angiogenic switch, no suppression of tumor growth was detected in HRG-deficient mice. Conclusions: Our data show that increased platelet activation mediates the accelerated angiogenic switch in HRG-deficient mice. Moreover, we conclude that platelets play a crucial role in the early stages of tumor development but are of less significance for tumor growth once angiogenesis has been initiated.
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| 44. |
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| 45. |
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| 46. |
- Storey, Robert F, et al.
(författare)
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Lower mortality following pulmonary adverse events and sepsis with ticagrelor compared to clopidogrel in the PLATO study
- 2014
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Ingår i: Platelets. - : Informa UK Limited. - 0953-7104 .- 1369-1635. ; 25:7, s. 517-525
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Tidskriftsartikel (refereegranskat)abstract
- In the PLATelet inhibition and patient Outcomes (PLATO) study of patients with acute coronary syndromes, ticagrelor reduced mortality compared to clopidogrel but the mechanisms for this mortality reduction remain uncertain. We analysed adverse events (AEs) consistent with either pulmonary infection or sepsis, and subsequent mortality, in 18,421 PLATO patients treated with ticagrelor or clopidogrel. AEs occurring within 7 days of last dose of study medication were defined as "on-treatment". Serial measurements of blood leukocyte counts, C-reactive protein and interleukin-6 were performed. Fewer on-treatment pulmonary AEs occurred in the ticagrelor compared to the clopidogrel group (275 vs. 331 respectively; p = 0.019), with fewer deaths following these AEs (33 vs. 71; p < 0.001), particularly in those who remained on study medication three days after AE onset (10 vs. 43; p < 0.001). There were fewer deaths attributed to sepsis in the ticagrelor group (7 vs. 23; p = 0.003). Leukocyte counts were lower in the clopidogrel group during treatment (p < 0.0001 at 1, 3 and 6 months) but not at 1 month post-discontinuation. C-reactive protein increased more at discharge in the ticagrelor group (28.0 ± 38.0 vs. 26.1 ± 36.6 mg/l; p < 0.001) and interleukin-6 remained higher during the first month of treatment with ticagrelor. We conclude that the mortality risk following pulmonary AEs and sepsis in acute coronary syndrome patients appears to be lower during ticagrelor compared to clopidogrel therapy. Further work should assess whether ticagrelor and clopidogrel have differential effects on immune signalling.
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| 47. |
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| 48. |
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| 49. |
- Uronen, Riikka-Liisa, et al.
(författare)
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Niemann-Pick C1 Modulates Hepatic Triglyceride Metabolism and Its Genetic Variation Contributes to Serum Triglyceride Levels
- 2010
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1524-4636 .- 1079-5642. ; 30:8, s. 230-1614
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Tidskriftsartikel (refereegranskat)abstract
- Objective-To study how Niemann-Pick disease type C1 (NPC1) influences hepatic triacylglycerol (TG) metabolism and to determine whether this is reflected in circulating lipid levels. Methods and Results-In Npc1(-/-) mice, the hepatic cholesterol content is increased but the TG content is decreased. We investigated lipid metabolism in Npc1(-/-) mouse hepatocytes and the association of NPC1 single-nucleotide polymorphisms with circulating TGs in humans. TGs were reduced in Npc1(-/-) mouse serum and hepatocytes. In Npc1(-/-) hepatocytes, the incorporation of [H-3] oleic acid and [H-3] acetate into TG was decreased, but shunting of oleic acid- or acetate-derived [H-3] carbons into cholesterol was increased. Inhibition of cholesterol synthesis normalized TG synthesis, content, and secretion in Npc1(-/-) hepatocytes, suggesting increased hepatic cholesterol neogenesis as a cause for the reduced TG content and secretion. We found a significant association between serum TG levels and 5 common NPC1 single-nucleotide polymorphisms in a cohort of 1053 men, with the lowest P=8.7 x 10(-4) for the single-nucleotide polymorphism rs1429934. The association between the rs1429934 A allele and higher TG levels was replicated in 2 additional cohorts, which included 8041 individuals. Conclusion-This study provides evidence of the following: (1) in mice, loss of NPC1 function reduces hepatocyte TG content and secretion by increasing the metabolic flux of carbons into cholesterol synthesis; and (2) common variation in NPC1 contributes to serum TG levels in humans. (Arterioscler Thromb Vasc Biol. 2010;30:1614-1620.)
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| 50. |
- Varenhorst, Christoph, 1977-
(författare)
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Platelet Inhibition in Coronary Artery Disease – Mechanisms and Clinical Importance : Studies with Focus on P2Y12 Inhibition
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Despite the currently recommended dual antiplatelet treatment (DAT) with aspirin and P2Y12 inhibition in patients with coronary artery disease (CAD) there is a risk of adverse clinical outcome. Pharmacodynamic (PD) poor response to clopidogrel occurs in ~ 30% of clopidogrel-treated patients and is associated with an increased risk of recurrent thrombotic events. The aims of this thesis were to compare the PD and pharmacokinetic effects of clopidogrel 600 mg loading dose (LD)/ 75 mg standard maintenance dose (MD) with the novel P2Y12 inhibitor prasugrel 60 mg LD/10 mg MD, in 110 patients with CAD. The mechanisms behind clopidogrel poor response were investigated by assessing the pharmacodynamics after adding clopidogrel active metabolite (AM) and genotyping for variation in CYP-genes involved in thienopyridine metabolism. In another study, we compared the on-clopidogrel platelet reactivity of patients with stent thrombosis (ST) (n=48) or myocardial infarction (MI) (n=30) while on DAT and their matched controls (n=50 + 28). Prasugrel achieved a faster and greater P2Y12-mediated platelet inhibition than clopidogrel measured with light transmission aggregometry, VASP and VerifyNow® P2Y12. Prasugrel’s greater platelet inhibition was associated with higher exposure of AM. The addition of clopidogrel AM led to maximal platelet inhibition in all subjects, suggesting that prasugrel’s greater antiplatelet effect was related to more efficient AM generation compared to that of clopidogrel. Lower levels of AM as well as less platelet inhibition were seen in clopidogrel-treated patients with reduced-metabolizer genotype CYP2C19 compared to those with normal genotype. Patients with ST while on DAT showed higher on-clopidogrel platelet reactivity compared to matched stented controls. Patients with spontaneous MI after stenting did not. In conclusion, these results showed a high rate PD poor response to a high bolus dose of clopidogrel because of a partly genetically caused lower generation of AM which could be overcome by prasugrel treatment. In patients after coronary stenting, clopidogrel poor response was related to ST but not to spontaneous MI, illustrating difficulties in optimizing treatment with clopidogrel based on platelet function or genetic testing in individual patients.
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