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Abstract: Introduction: Off-target effects of novel antiplatelet agents due to their potential clinical benefits are currently an area of intensive investigation. We aimed to compare the effects of different P2Y12 antagonists on the reactivity of vascular smooth muscle cells. Materials and methods: Wistar rats (n=30) were pretreated with an investigated drug or placebo. Clopidogrel (50mg/kg, n=7), prasugrel (10mg/kg, n=7), ticagrelor (10mg/kg, n=7) or placebo (n=9) were administered orally 12 and 2hours before experiments. Constrictions of rat tail arteries induced with a stable analogue of adenosine diphosphate (2-MeS-ADP), phenylephrine and arginine vasopressin were measured as an increase in perfusion pressure. Effects of ticagrelor were assessed in the presence of ticagrelor (1μM/L) added to the perfusion solution as this drug reversibly inhibits the P2Y12 receptor. Results: Pretreatment with clopidogrel and prasugrel did not inhibit 2-MeS-ADP-induced contraction while ticagrelor did. Experiments employing endothelium-deprived arteries provided similar results. Clopidogrel and prasugrel did not influence concentration-response curves in the presence of neither phenylephrine nor arginine vasopressin. The curves obtained for both vasopressors in the presence of ticagrelor and 2-MeS-ADP were shifted to the right with a significant reduction in the maximal response. Conclusions: Oral administration of ticagrelor, in contrast to clopidogrel and prasugrel, prevents adenosine diphosphate-induced contraction of vascular smooth muscle cells in a rat model. Both the clinical significance and detailed mechanism of our findings warrant further investigation. [Copyright &y& Elsevier]

Objective. To compare effects of low-versus high-dose aspirin coadministered with ticagrelor on the reactivity of vascular smooth muscle cells (VSMCs). Methods. Wistar rats were orally administered ticagrelor (10 mg/kg) and/or aspirin (2 or 10 mg/kg) (n = 7 per each of 4 groups) or placebo (n = 9) 12 and 2 hours before experiments. Anticontractile effects of ticagrelor were assessed in perfusion solution containing ticagrelor (1 M/L). Changes in perfusion pressure proportional to the degree of adenosine diphosphate analogue-(2-MeS-ADP-) and phenylephrine-induced constriction of rat tail arteries were evaluated. Results. Pretreatment with high- but not low-dose aspirin enhanced the reactivity of VSMCs only in endothelium-lined vessels. Suppression of 2-MeS-ADP-induced VSMC contraction by ticagrelor observed in arteries with and without endothelium was maintained in endothelialized arteries pretreated only with low-dose aspirin. For endothelium-denuded vessels and low-dose aspirin we observed a significant reduction of the maximal effect of ticagrelor with no rightward shift of the concentration-response curve for phenylephrine. With high-dose aspirin pretreatment ticagrelor exerted no anticontractile effect. Conclusion. High-dose, but not low-dose, aspirin impairs the anticontractile effect of ticagrelor on ADP-induced VSMC contraction in the rat model. Both the clinical significance and detailed underlying mechanism of our findings require further investigation. [ABSTRACT FROM AUTHOR]

Rho-kinase and GTP-ase Rho are important regulators of vascular tone and blood pressure. The aim of this study was to investigate the role of Rho-kinase in artery reactions induced by angiotensin II (ANG II) and the effects of ischemia-reperfusion injury as well as the function of intra- and extracellular calcium in these reactions. Experiments were performed on mesenteric superior arteries procured from cadaveric organ donors and conserved under the same conditions as transplanted kidneys. The vascular contraction in reaction to ANG II was measured in the presence of Rho-kinase inhibitor Y-27632, after ischemia and reperfusion, in Ca2+ and Ca2+-free solution. The maximal response to ANG II was reduced after ischemia, while an increase was observed after reperfusion. Vascular contraction induced by ANG II was decreased by Y-27632. Y-27632 reduced vascular contraction after reperfusion, both in Ca2+ and Ca2+-free solution. Reperfusion augments vascular contraction in reaction to ANG II. The Rho-kinase inhibitor Y-27632 reduces the hypersensitivity to ANG II after reperfusion mediated by both intra- and extracellular calcium. These results confirm the role of Rho-kinase in receptor-independent function of ANG II and in reperfusion-induced hypersensitivity. [ABSTRACT FROM AUTHOR]

Recent reports indicate that statins are associated with an increased risk for new-onset diabetes mellitus (DM) compared with placebo and that this relation is dose dependent. The aim of this study was to perform a comprehensive network meta-analysis of randomized controlled trials (RCTs) investigating the impact of different types and doses of statins on new-onset DM. RCTs comparing different types and doses of statins with placebo were searched for using the MEDLINE, Embase, and Cochrane databases. A search of RCTs pertinent to this meta-analysis covering the period from November 1994 to October 2012 was conducted by 2 independent investigators using the MEDLINE, Cochrane, Google Scholar, and Embase databases as well as abstracts and presentations from major cardiovascular meetings. Seventeen RCTs reporting the incidence of new-onset DM during statin treatment and including a total of 113,394 patients were identified. The RCTs compared either a statin versus placebo or high-dose versus moderate-dose statin therapy. Among different statins, pravastatin 40 mg/day was associated with the lowest risk for new-onset DM compared with placebo (odds ratio 1.07, 95% credible interval 0.86 to 1.30). Conversely, rosuvastatin 20 mg/day was numerically associated with 25% increased risk for DM compared with placebo (odds ratio 1.25, 95% credible interval 0.82 to 1.90). The impact on DM appeared to be intermediate with atorvastatin 80 mg/day compared with placebo (odds ratio 1.15, 95% credible interval 0.90 to 1.50). These findings were replicated at moderate doses. In conclusion, different types and doses of statins show different potential to increase the incidence of DM. [ABSTRACT FROM AUTHOR]

Recent reports indicate that statins are associated with an increased risk for new-onset diabetes mellitus (DM) compared with placebo and that this relation is dose dependent. The aim of this study was to perform a comprehensive network meta-analysis of randomized controlled trials (RCTs) investigating the impact of different types and doses of statins on new-onset DM. RCTs comparing different types and doses of statins with placebo were searched for using the MEDLINE, Embase, and Cochrane databases. A search of RCTs pertinent to this meta-analysis covering the period from November 1994 to October 2012 was conducted by 2 independent investigators using the MEDLINE, Cochrane, Google Scholar, and Embase databases as well as abstracts and presentations from major cardio-vascular meetings. Seventeen RCTs reporting the incidence of new-onset DM during statin treatment and including a total of 113,394 patients were identified. The RCTs compared either a statin versus placebo or high-dose versus moderate-dose statin therapy. Among different statins, pravastatin 40 mg/day was associated with the lowest risk for new-onset DM compared with placebo (odds ratio 1.07, 95% credible interval 0.86 to 1.30). Conversely, rosuvastatin 20 mg/day was numerically associated with 25% increased risk for DM compared with placebo (odds ratio 1.25, 95% credible interval 0.82 to 1.90). The impact on DM appeared to be intermediate with atorvastatin 80 mg/day compared with placebo (odds ratio 1.15, 95% credible interval 0.90 to 1.50). These findings were replicated at moderate doses. In conclusion, different types and doses of statins show different potential to increase the incidence of DM. [ABSTRACT FROM AUTHOR]

Background: Ticagrelor is an oral platelet P2Y12 receptor antagonist which is recommended for patients suffering from myocardial infarction, both with and without persistent ST segment elevation. Morphine is the first choice drug in pain alleviation in the same clinical subset. Recently a possible negative influence of morphine on the pharmacokinetics and antiplatelet effects of P2Y12 receptor blockers has been postulated.Methods/design: The IMPRESSION study is a phase IV, single center, randomized, double-blind, placebo-controlled clinical trial that is designed to assess the influence of morphine on the pharmacokinetics and pharmacodynamics of ticagrelor in patients with myocardial infarction. The study is planned to include up to 100 patients with myocardial infarction who will be randomized into one of two arms in a 1:1 ratio. Subjects in the intervention arm prior to the loading dose of ticagrelor (180 mg) will receive morphine (5 mg) intravenously, whereas patients in the control arm will receive a placebo prior to the loading dose of ticagrelor (180 mg). The pharmacokinetics of ticagrelor and its active metabolite (AR-C124910XX) will be assessed by liquid chromatography mass spectrometry. Platelet function testing in each patient will be performed using up to four different methods (platelet vasodilator-stimulated phosphoprotein assay, multiple electrode aggregometry, VerifyNow, and light transmission aggregometry).Discussion: This study is expected to provide essential evidence-based data on the impact of morphine on the absorption of ticagrelor in patients with myocardial infarction as well as to shed some light on the suspected connection between morphine use and antiplatelet activity of ticagrelor in the same group of patients.Trial Registration: ClinicalTrials.gov identifier: NCT02217878 (14 August 2014). [ABSTRACT FROM AUTHOR]