Search results for "platelet aggregation inhibitors"
showing 10 items of 105 documents
Vitamin C blocks inflammatory platelet-activating factor mimetics created by cigarette smoking.
1997
Cigarette smoking within minutes induces leukocyte adhesion to the vascular wall and formation of intravascular leukocyte-platelet aggregates. We find this is inhibited by platelet-activating factor (PAF) receptor antagonists, and correlates with the accumulation of PAF-like mediators in the blood of cigarette smoke-exposed hamsters. These mediators were PAF-like lipids, formed by nonenzymatic oxidative modification of existing phospholipids, that were distinct from biosynthetic PAF. These PAF-like lipids induced isolated human monocytes and platelets to aggregate, which greatly increased their secretion of IL-8 and macrophage inflammatory protein-1alpha. Both events were blocked by a PAF r…
Time-resolved characterization of cAMP/PKA-dependent signaling reveals that platelet inhibition is a concerted process involving multiple signaling p…
2014
One of the most important physiological platelet inhibitors is endothelium-derived prostacyclin which stimulates the platelet cyclic adenosine monophosphate/protein kinase A (cAMP/PKA)-signaling cascade and inhibits virtually all platelet-activating key mechanisms. Using quantitative mass spectrometry, we analyzed time-resolved phosphorylation patterns in human platelets after treatment with iloprost, a stable prostacyclin analog, for 0, 10, 30, and 60 seconds to characterize key mediators of platelet inhibition and activation in 3 independent biological replicates. We quantified over 2700 different phosphorylated peptides of which 360 were significantly regulated upon stimulation. This com…
In-vitro and Ex-vivo Inhibition of Blood Platelet Aggregation by Naftazone
1996
Abstract Because of the considerable interest in the role of platelets and antiplatelet therapy in cardiovascular disease, including the aggregation of platelets to each other during arterial thrombosis and atherogenesis, we have studied the effect of naftazone (Etioven), an original vasculotropic drug on platelet aggregation. Rat and human platelets were prepared and incubated in-vitro with different concentrations of naftazone. We found that naftazone inhibited both platelet secretion and aggregation in platelet-rich plasma (PRP) and washed platelets after stimulation with thrombin or ADP. Rats were also treated intraperitoneally for five days with various naftazone doses (0.125-10 mg kg−…
PHOSPHODIESTERASE INHIBITORS PIROXIMONE AND ENOXIMONE INHIBIT PLATELET AGGREGATION IN VIVO AND IN VITRO
1997
The phosphodiesterase type III inhibitors piroximone (PIR) and enoximone (ENO) exert positive inotropic and vasodilating effects in patients with severe heart failure. PIR and ENO raise cyclic AMP levels in cardiac and vascular smooth muscle cells. Platelet activity is also regulated by intracellular levels of cyclic AMP. In this study we have investigated the effects of PIR and ENO on platelet activity in vivo and in vitro. PIR and ENO inhibited ADP induced platelet aggregation in a time- and concentration-dependent manner with IC50-values of 67 +/- 14 mumol/l and 129 +/- 6 mumol/l, respectively. Coincubation of PIR with the adenylate cyclase activator iloprost resulted in a synergistic po…
The histone deacetylase sirtuin 2 is a new player in the regulation of platelet function
2015
SummaryBackground Histone deacetylases (HDACs) play a key role in signaling in many cell types. However, little is known about the participation of HDACs, particularly sirtuins (SIRTs), in platelet reactivity. Objective To investigate the role of HDACs in platelets, we examined the effects of SIRT inhibition on platelet function and protein acetylation in human platelets. Methods We used washed platelets obtained from healthy subjects. Cambinol (SIRT1 and SIRT2 inhibitor), AGK2 (specific SIRT2 inhibitor) and EX527 (specific SIRT1 inhibitor) were used as SIRT inhibitors. Platelets were stimulated with collagen, thrombin, or U46619, and platelet responses were determined according to optical …
Synergistic interaction of adenylate cyclase activators and nitric oxide donor SIN-1 on platelet cyclic AMP
1995
Abstract The molecular mechanism of the synergistic platelet inhibition by activators of adenylate cyclase and guanylate cyclase in human platelets was investigated. The adenylate cyclase activators iloprost and prostaglandin E 1 and the guanylate cyclase activator 3-morpholino-synonimine (SIN-1) dose-dependently inhibited thrombin-induced aggregation of washed human platelets. Furthermore, SIN-1 at a concentration inhibiting platelet aggregation by only 10% shifted the IC 50 values of iloprost and prostaglandin E 1 by one order of magnitude to the left, indicating a synergistic action of adenylate cyclase and guanylate cyclase activators. Iloprost and prostaglandin E 1 dose-dependently ele…
Increased Platelet Sensitivity toward Platelet Inhibitors during Physical Exercise in Patients with Coronary Artery Disease
1999
Generalized atherosclerosis and coronary artery disease (CAD) are associated with endothelial dysfunction and during acute myocardial ischemia platelet activation has been reported. Activated platelets exert activated fibrinogen receptors (GP IIb/IIIa) and express CD 62p being regarded as reliable marker for platelet activation. Patients with angiographically proven CAD performed a bicycle exercise test until the onset of angina or ST-segment depression. We studied the ischemia-induced alterations in fibrinogen binding to activated platelet GP IIb/IIIa receptors and CD 62p expression. Therefore, the basal fibrinogen binding to GP IIb/IIIa and CD 62p expression and the thrombin-concentration…
Prevalence of older in-patients at risk of clopidogrel resistance according to the STIB score. Results from REPOSI registry
2017
The phenomenon of resistance to copidogrel catches the attention of a growing number of clinicians because of its frequency and the severity of adverse events related to it. The identification of patients with high platelet reactivity (HPR may help to improve their therapy applying the concept of personalized medicine, most important in the older people treated with polypharmacy. The existece of such a simple clinical method as the STIB score, that allows to predict the possible resistace to clopidogrel at the bedside without using expensive laboratory investigations, provides an attractive approach to the problem.
Role of genetic factors on the effect of additional loading doses and two maintenance doses used to overcome clopidogrel hyporesponsiveness.
2014
Background and objective: Additional loading doses and higher maintenance doses (MDs) have been used to overcome hyporesponsiveness of clopidogrel. We aimed to investigate whether genetic polymorphisms of two cytochromes (CYP2C19 and CYP2C9) and ABCB1 modify effect of such dose-adjustment strategy.Materials and methods: We enrolled 118 patients undergoing elective or acute percutaneous coronary intervention (PCI) with drug eluting stent (DES). Platelet reactivity index (PRI) was measured using the vasodilator-stimulated phosphoprotein (VASP) index and a cut-off value of ≥60% was defined as hyporesponsiveness. Polymorphism of two cytochromes (CYP2C19, CYP2C9) and gene ABCB1 were determined. …
Management of Patients with Asymptomatic and Symptomatic Carotid Artery Disease: Update on Anti-Thrombotic Therapy
2019
AbstractThe most common causes of ischaemic stroke are represented by carotid artery atherosclerotic disease (CAAD) and atrial fibrillation. While oral anticoagulants substantially reduce the incidence of thromboembolic stroke (< 1%/year), the rate of ischaemic stroke and other cardiovascular disease events in patients with CAAD remains high, ranging from 8.4 to 18.1 events per 100 patient-years. Similar to any other atherosclerotic disease, anti-thrombotic therapies are proposed for CAAD to reduce stroke and other cardiovascular events. The 2017 European Society of Cardiology (ESC)/European Society for Vascular Surgery (ESVS) guidelines recommend for patients with asymptomatic CAAD ≥60%…