Antiplatelet drugs block platelet activation by VITT patient serum.
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ABSTRACT:
SUBMITTER: Smith CW
PROVIDER: S-EPMC8697531 | biostudies-literature | 2021 Dec
REPOSITORIES: biostudies-literature
Publications
Antiplatelet drugs block platelet activation by VITT patient serum.
Smith Christopher W CW Montague Samantha J SJ Kardeby Caroline C Di Ying Y Lowe Gillian C GC Lester William A WA Watson Steve P SP Nicolson Phillip L R PLR
Blood 20211201 25
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Project description:Activated platelets are involved in blood coagulation by exposing phosphatidylserine (PS), which serves as a substrate for assembling coagulation complexes. Platelets accelerate fibrin formation and thrombin generation, two final reactions of the coagulation cascade. We investigated the effects of antiplatelet drugs on platelet impact in these reactions and platelet ability to expose PS. Washed human platelets were incubated with acetylsalicylic acid (ASA), ticagrelor, ASA in combination with ticagrelor, ruciromab (glycoprotein IIb-IIIa antagonist), or prostaglandin E1 (PGE1). Platelets were not activated or activated by collagen and sedimented in multiwell plates, and plasma was added after supernatant removal. Fibrin formation (clotting) was monitored in a recalcification assay by light absorbance and thrombin generation in a fluorogenic test. PS exposure was assessed by annexin V staining using flow cytometry. Ticagrelor (alone and in combination with ASA), ruciromab, and PGE1, but not ASA, prolonged the lag phase and decreased the maximum rate of plasma clotting and decreased the peak and maximum rate of thrombin generation. Inhibition was observed when platelets were not treated with exogenous agonists (activation by endogenous thrombin) and pretreated with collagen. Ticagrelor (alone and in combination with ASA), ruciromab, and PGE1, but not ASA, decreased PS exposure on washed platelets activated by thrombin and by thrombin + collagen. PS exposure on activated platelets in whole blood was lower in patients with acute coronary syndrome receiving ticagrelor + ASA in comparison with donors free of medications. These results indicate that antiplatelet drugs are able to suppress platelet coagulation activity not only in vitro but also after administration to patients.
| S-EPMC10377112 | biostudies-literature
Project description:BackgroundVITT has emerged as a rare but serious adverse event linked primarily to adenoviral vector COVID-19 vaccinations, such as ChAdOx1-S (Oxford/AstraZeneca) vaccination. The syndrome is characterized by thrombosis with thrombocytopenia, elevated D-dimer, and pathologic platelet factor 4 antibodies within 42 days of vaccination.ObjectivesDespite dysregulated lipid metabolism underpinning many thrombotic conditions, the role of lipid alterations in VITT remains unexplored. Here, we examined the plasma lipidome of patients with VITT and compared it with those following ChAdOx1-S vaccination and with unprovoked venous thromboembolism (VTE) to understand the role of lipids in VITT pathophysiology.MethodsThis was a multicenter, prospective cohort study evaluating plasma lipidomics in newly diagnosed VITT samples, which were compared with both healthy controls following ChAdOx1-S vaccination and with unprovoked VTE.ResultsComparison with ChAdOx1-S controls reveals a distinct lipid signature in VITT, characterized by elevations in phosphatidylserine and ceramide species, alongside reductions in several plasmalogens and acylcarnitine species. Notably, similarities between VITT lipid profiles and insulin resistance phenotypes suggest potential metabolic susceptibility. While few significant associations were found between VITT and VTE, an inverse correlation with several acylcarnitine species was demonstrated. Given the known anticoagulant role of acylcarnitine species, these findings suggest a plausible mechanistic pathway elevating the thrombotic potential of VITT above that of standard VTE.ConclusionThese findings underscore the important role of lipid metabolism in VITT pathophysiology and highlight the complex interplay between lipids, coagulation, and pathologic thrombosis.
| S-EPMC11879676 | biostudies-literature
Project description:The purpose of this study was to identify changes in platelet mRNA that result from exposure to antiplatelet therapy. A total of 84 healthy volunteers were recruited into a longitudinal study of various antiplatelet exposures with 58 completing all study visits. This was a 5 visit study where each visit was separated by ~ 4 weeks. At each Visit purified platelets using a CD45 negative selection protocol was performed in addition to platelet function testing using light transmittance aggregometry (ADP, EPI, and Collagen) and PFA100 (Col/EPI). After the baseline visit (V1), participants were randomized to receive 81mg/day or 325mg/day aspirin x 4 weeks followed by Visit 2. Participants then crossed over to the alternative dose of aspirin for 4 weeks followed by Visit 3. Between Visits 3 and 4 participants washed out their aspirin for 4 weeks. The final exposure was ticagrelor 90mg twice daily x 4 weeks until Visit 5.
2022-03-14 | GSE158765 | GEO
Project description: Not available
| S-EPMC9262283 | biostudies-literature
Project description:BackgroundCoronavirus disease 2019 (COVID-19) is associated with an inflammatory cytokine burst and a prothrombotic coagulopathy. Platelets may contribute to microthrombosis, and constitute a therapeutic target in COVID-19 therapy.AimTo assess if platelet activation influences mortality in COVID-19.MethodsWe explored two cohorts of patients with COVID-19. Cohort A included 208 ambulatory and hospitalized patients with varying clinical severities and non-COVID patients as controls, in whom plasma concentrations of the soluble platelet activation biomarkers CD40 ligand (sCD40L) and P-selectin (sP-sel) were quantified within the first 48hours following hospitalization. Cohort B was a multicentre cohort of 2878 patients initially admitted to a medical ward. In both cohorts, the primary outcome was in-hospital mortality.ResultsIn cohort A, median circulating concentrations of sCD40L and sP-sel were only increased in the 89 critical patients compared with non-COVID controls: sP-sel 40,059 (interquartile range 26,876-54,678)pg/mL; sCD40L 1914 (interquartile range 1410-2367)pg/mL (P<0.001 for both). A strong association existed between sP-sel concentration and in-hospital mortality (Kaplan-Meier log-rank P=0.004). However, in a Cox model considering biomarkers of immunothrombosis, sP-sel was no longer associated with mortality, in contrast to coagulopathy evaluated with D-dimer concentration (hazard ratio 4.86, 95% confidence interval 1.64-12.50). Moreover, in cohort B, a Cox model adjusted for co-morbidities suggested that prehospitalization antiplatelet agents had no significant impact on in-hospital mortality (hazard ratio 1.05, 95% CI 0.80-1.37; P=0.73).ConclusionsAlthough we observed an association between excessive biomarkers of platelet activation and in-hospital mortality, our findings rather suggest that coagulopathy is more central in driving disease progression, which may explain why prehospitalization antiplatelet drugs were not a protective factor against mortality in our multicentre cohort.
| S-EPMC9925415 | biostudies-literature
Project description:BackgroundAntiplatelet medications are increasingly used in dogs. Remote analysis of platelet activity is challenging, limiting assessment of antiplatelet drug efficacy.Hypothesis/objectivesTo evaluate a method used in humans for stimulation and remote analysis of canine platelet activity.AnimalsForty-five dogs of various ages without a coagulopathy or thrombocytopenia. Six were receiving antiplatelet medication.MethodsProspective observational study. Platelets were stimulated with combinations of arachidonic acid (AA) and epinephrine (Epi) or adenosine diphosphate (ADP) and the thromboxane A2 -mimetic U46619 (U4). PAMFix was added to the blood samples to facilitate delayed analysis of platelet activity. Activity was assessed by flow cytometric measurement of surface P-selectin (CD62P) expression.ResultsCanine platelets could be stimulated with both AA/Epi and ADP/U4. The levels of P-selectin were significantly greater than paired, unstimulated samples (P < 0.001). Inhibition of P-selectin expression occurred after this stimulation by adding antiplatelet drugs in vitro. The efficacy of antiplatelet drugs in samples from treated dogs was also measurable ex vivo using this method. Delayed analysis of platelet activity at time points up to 22 days demonstrated excellent correlation between respective mf values at each time point (r2 = 0.92, P < 0.0001).Conclusions and clinical importanceThis study evaluated a new method to remotely assess canine platelet activity. It shows that PAMFix can be used for this purpose. This provides opportunities to interrogate the inhibitory action of antiplatelet drugs in clinical settings.
| S-EPMC5787215 | biostudies-literature
Project description:Platelet mRNA in response to antiplatelet therapy exposure
| PRJNA666442 | ENA
Project description:Cardiovascular diseases are the leading cause of death in the Western world. Several factors have led to the increase in vascular disorders, including the aging population, unhealthy lifestyles, increasing rates of diabetes and raised lipids, and further risk factors resulting in inflammation and calcification of the vascular endothelium. Activated platelets in damaged blood vessels can trigger arterial thrombus formation, leading to vascular occlusion with subsequent organ hypoperfusion and clinical manifestation of myocardial infarction, stroke, or peripheral artery disease. Platelet inhibitors such as aspirin and clopidogrel (Plavix(®) and generics) are prescribed as primary or secondary prevention to attenuate chronic platelet activation. However, a significant proportion of patients do not respond adequately to uniform antiplatelet treatment. These 'non-responders' have an increased risk for stent thrombosis, stroke, and other ischemic complications. Platelet function (PF) tests can identify these patients thus enabling physicians to offer personalized and alternative treatment strategies. Recent alternatives to clopidogrel include prasugrel (Efient(®)) and ticagrelor (Brilique(®)) - that are both more potent than clopidogrel but also more expensive and associated with a higher risk of bleeding complications. Given these drawbacks, PF testing might help clinicians to prescribe optimal antiplatelet agent to maximize patient safety and efficacy while minimizing costs. While randomized studies using different test systems have left clinicians puzzled about the medical value of tailored antiplatelet therapy, accumulated evidence from recent studies on tailored antiplatelet therapies and the association with improved outcomes have now resulted in a consensus expert opinion for the specific adoption of PF diagnostics into clinical practice.
| S-EPMC4975182 | biostudies-other
Project description:Vaccination is crucial in combatting the severe acute respiratory syndrome coronavirus 2 pandemic. The rare complication of thrombocytopenia and thrombotic complications at unusual sites after ChAdOx1 nCov-19 vaccination is caused by platelet-activating antibodies directed against platelet factor 4 (PF4). We present a widely applicable whole-blood standard flow cytometric assay to identify the pathogenic antibodies associated with vaccine-induced immune-mediated thrombotic thrombocytopenia (VITT) after ChAdOx1 nCov-19 vaccination. This assay will enable rapid diagnosis by many laboratories. This trial was registered at www.clinicaltrials.gov as #NCT04370119.
| S-EPMC8105122 | biostudies-literature
Project description:BackgroundDuring long-term antiplatelet agents (APAs) administration, patients with thrombotic diseases take a fairly high risk of life-threatening bleeding, especially when in need of urgent surgery. Rapid functional reversal of APAs remains an issue yet to be efficiently resolved by far due to the lack of any specific reversal agent in the clinic, which greatly restricts the use of APAs.MethodsFlow cytometry analysis was first applied to assess the dose-dependent reversal activity of platelet-mimicking perfluorocarbon-based nanosponges (PLT-PFCs) toward ticagrelor. The tail bleeding time of mice treated with APAs followed by PLT-PFCs was recorded at different time points, along with corresponding pharmacokinetic analysis of ticagrelor and tirofiban. A hemorrhagic transformation model was established in experimental stroke mice with thrombolytic/antiplatelet therapy. Magnetic resonance imaging was subsequently applied to observe hemorrhage and thrombosis in vivo. Further evaluation of the spontaneous clot formation activity of PLT-PFCs was achieved by clot retraction assay in vitro.ResultsPLT-PFCs potently reversed the antiplatelet effect of APAs by competitively binding with APAs. PLT-PFCs showed high binding affinity comparable to fresh platelets in vitro with first-line APAs, ticagrelor and tirofiban, and efficiently reversed their function in both tail bleeding and postischemic-reperfusion models. Moreover, the deficiency of platelet intrinsic thrombotic activity diminished the risk of thrombogenesis.ConclusionsThis study demonstrated the safety and effectiveness of platelet-mimicking nanosponges in ameliorating the bleeding risk of different APAs, which offers a promising strategy for the management of bleeding complications induced by antiplatelet therapy.
| S-EPMC9891290 | biostudies-literature