Association of Lipoprotein(a) levels with intrinsic and on-clopidogrel platelet reactivity

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Kille ◽  
T Nuehrenberg ◽  
C.M Valina ◽  
F.J Neumann ◽  
W Hochholzer
Keyword(s):  
Flow Cytometry ◽  
Platelet Function ◽  
Platelet Reactivity ◽  
Laboratory Data ◽  
Secondary Analysis ◽  
Structural Similarity ◽  
Lipoprotein A ◽  
Causal Risk Factor ◽  
Premature Cardiovascular Disease ◽  
Potential Association

Abstract Background Lipoprotein(a) [Lp(a)] is an independent, genetic, and causal risk factor for premature cardiovascular disease (CVD). Laboratory data have suggested an interaction of Lp(a) with platelet function, potentially caused by its structural similarity to plasminogen. So far, the potential association of Lp(a) with platelet activation and reactivity has not been well established in larger clinical cohorts. Methods This secondary analysis of the EXCELSIOR study analyzed intrinsic platelet reactivity before loading with clopidogrel 600mg and on-treatment platelet reactivity tested 24 hours following loading in patients undergoing elective coronary angiography. Platelet reactivity was tested by optical aggregometry as final aggregation after 5 min following stimulation with 5μM ADP. Platelet reactivity was also assessed by flow cytometry (expression of CD62P and PAC1) following stimulation with ADP and TRAP. Levels of Lp(a) on admission of each patient were immediately measured from fresh samples in a central laboratory. Results The present analysis included 2046 patients. Levels of Lp(a) ranged between 0 and 332 mg/dl. Results for intrinsic (p=0.80) and on-clopidogrel platelet reactivity (p=0.81) did not differ between quartiles of Lp(a) levels (Figure). Flow cytometry analyses confirmed these findings. Conclusion The present data do not support the hypothesis of an interaction of Lp(a) with platelet function. This finding might be important to define the safety of evolving therapeutic options for lowering Lp(a). Funding Acknowledgement Type of funding source: None

scholarly journals Association of lipoprotein(a) with intrinsic and on-clopidogrel platelet reactivity

2021 ◽  
Author(s):  
Alexander Kille ◽  
Thomas Nührenberg ◽  
Kilian Franke ◽  
Christian M. Valina ◽  
Gregor Leibundgut ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Platelet Activation ◽  
Platelet Reactivity ◽  
Laboratory Data ◽  
Adenosine Diphosphate ◽  
Surface Proteins ◽  
Activation Markers ◽  
Platelet Surface ◽  
Lipoprotein A ◽  
Artery Disease

AbstractLipoprotein(a) [Lp(a)] is an independent, genetically determined, and causal risk factor for cardiovascular disease. Laboratory data have suggested an interaction of Lp(a) with platelet function, potentially caused by its interaction with platelet receptors. So far, the potential association of Lp(a) with platelet activation and reactivity has not been proven in larger clinical cohorts. This study analyzed intrinsic platelet reactivity before loading with clopidogrel 600 mg and on-treatment platelet reactivity tested 24 h following loading in patients undergoing elective coronary angiography. Platelet reactivity was tested by optical aggregometry following stimulation with collagen or adenosine diphosphate as well as by flow cytometry. Lp(a) levels were directly measured in all patients from fresh samples. The present analysis included 1912 patients. Lp(a) levels ranged between 0 and 332 mg/dl. There was a significant association of rising levels of Lp(a) with a higher prevalence of a history of ischemic heart disease (p < 0.001) and more extensive coronary artery disease (p = 0.001). Results for intrinsic (p = 0.80) and on-clopidogrel platelet reactivity (p = 0.81) did not differ between quartiles of Lp(a) levels. Flow cytometry analyses of expression of different platelet surface proteins (CD41, CD62P or PAC-1) confirmed these findings. Correlation analyses of levels of Lp(a) with any of the tested platelet activation markers did not show any correlation. The present data do not support the hypothesis of an interaction of Lp(a) with platelet reactivity.

Toward Flow Cytometry Based Platelet Function Diagnostics

2018 ◽  
Vol 44 (03) ◽  
pp. 197-205 ◽  
Author(s):  
Ivar van Asten ◽  
Roger Schutgens ◽  
Rolf Urbanus
Keyword(s):  
Flow Cytometry ◽  
Platelet Function ◽  
Platelet Reactivity ◽  
Diagnostic Tools ◽  
Laboratory Diagnostics ◽  
Main Challenge ◽  
Platelet Function Disorders ◽  
Diagnostic Work ◽  
Work Up ◽  
Diagnostic Work Up

AbstractThe laboratory diagnostics of (inherited) platelet function disorders mainly comprises aggregation and secretion assays, which may be suitable for diagnosing some specific severe platelet function disorders, but are not reliable enough for diagnosing mild platelet function disorders or disorders associated with low platelet count. Flow cytometric assessment of platelet reactivity will expectedly provide additional value during the diagnostic work-up of platelet function disorders because it only requires a small volume of whole blood and allows the measurement of platelet function in thrombocytopenic samples. Flow cytometry has frequently been used to evaluate platelet function in the research setting, and therefore, these assays will require clinical validation before they can be used as routine diagnostic tools. The main challenge in the validation of innovative platelet function diagnostic tests is the lack of a gold standard test for mild platelet function disorders. This review aims to address the many applications of flow cytometry in the current diagnostic work-up of platelet function testing and to discuss the challenges in introducing new tools for diagnosing platelet function disorders.

Decreased platelet reactivity identified by whole blood flow cytometry in Fanconi anaemia patients

2007 ◽  
Vol 98 (12) ◽  
pp. 1291-1297 ◽  
Author(s):  
Susanne Holzhauer ◽  
Ana-Gabriela Sitaru ◽  
Wolfram Ebell ◽  
Detlev Schindler ◽  
Helmut Hanenberg ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Blood Flow ◽  
Platelet Function ◽  
Whole Blood ◽  
Platelet Reactivity ◽  
Bone Marrow Failure ◽  
Receptor Expression ◽  
Platelet Glycoprotein ◽  
Bleeding Tendency ◽  
Reticulated Platelets

Summarydisorder characterized by congenital anomalies and a high risk for bone marrow failure and cancer. Bleeding is a frequent complication in FA, leading to substantial morbidity and mortality. Thrombocytopenia is a major factor leading to this complication, but the bleeding tendency of FA patients often exceeds what one might expect based on their platelet counts. We therefore investigated if alterations of platelet function contribute to the bleeding tendency of FA patients. We assessed platelet function in 11 FA patients and 23 controls with whole blood flow cytometry. We analyzed the expression of platelet membrane glycoprotein receptors, reactivity of platelets to physiologic agonists and the proportion of young platelets. In FA patients platelet PAC-1 after stimulation with thrombin receptor activating peptide (TRAP) and adenosine diphosphate (ADP) were 15–70% lower than in controls. We found no or only minor differences of platelet glycoprotein receptor expression between groups. While the proportion of reticulated platelets was not different, the absolute number of reticulated platelets was markedly lower in FA patients. Our data show that FA is associated with reduced platelet reactivity, which may contribute to the high bleeding tendency in FA patients. Whole blood flow cytometry is a suitable method for analysis of platelet function in FA patients.

scholarly journals Head-to-Head Comparison of Consensus-Recommended Platelet Function Tests to Assess P2Y12 Inhibition—Insights for Multi-Center Trials

2020 ◽  
Vol 9 (2) ◽  
pp. 332
Author(s):  
Jean-Christophe Bélanger ◽  
Fabio Luiz Bandeira Ferreira ◽  
Mélanie Welman ◽  
Rahma Boulahya ◽  
Jean-François Tanguay ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Platelet Reactivity ◽  
Receptor Activation ◽  
P2y12 Receptor ◽  
Reactivity Index ◽  
Specific Method ◽  
Vasp Phosphorylation ◽  
Receptor Inhibitor

The vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation level is a highly specific method to assess P2Y12 receptor inhibition. Traditionally, VASP phosphorylation is analyzed by flow cytometry, which is laborious and restricted to specialized laboratories. Recently, a simple ELISA kit has been commercialized. The primary objective of this study was to compare the performance of VASP assessment by ELISA and flow cytometry in relation to functional platelet aggregation testing by Multiplate® whole-blood aggregometry. Blood from 24 healthy volunteers was incubated with increasing concentration of a P2Y12 receptor inhibitor (AR-C 66096). Platelet function testing was carried out simultaneously by Multiplate® aggregometry and by VASP assessment through ELISA and flow cytometry. As expected, increasing concentrations of the P2Y12 receptor inhibitor induced a proportional inhibition of platelet aggregation and P2Y12 receptor activation across the modalities. Platelet reactivity index values of both ELISA- and flow cytometry-based VASP assessment methods correlated strongly (r = 0.87, p < 0.0001) and showed minimal bias (1.05%). Correlation with Multiplate® was slightly higher for the flow cytometry-based VASP assay (r = 0.79, p < 0.0001) than for the ELISA-based assay (r = 0.69, p < 0.0001). Intraclass correlation (ICC) was moderate for all the assays tested (ICC between 0.62 and 0.84). However, categorization into low, optimal, or high platelet reactivity based on these assays was strongly concordant (κ between 0.86 and 0.92). In conclusion, the consensus-recommended assays with their standardized cut-offs should not be used interchangeably in multi-center clinical studies but, rather, they should be standardized throughout sites.

Unexpected persistence of platelet hyporeactivity beyond the neonatal period: a flow cytometric study in neonates, infants and older children

2003 ◽  
Vol 90 (07) ◽  
pp. 116-123 ◽  
Author(s):  
Nathalie Hézard ◽  
Gérard Potron ◽  
Nicole Schlegel ◽  
Catherine Amory ◽  
Bernard Leroux ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Platelet Function ◽  
Neonatal Period ◽  
Platelet Reactivity ◽  
Older Children ◽  
Flow Cytometric ◽  
Activated Platelets ◽  
Age Dependent ◽  
Flow Cytometric Study ◽  
Αiibβ3 Integrin

SummaryPrevious studies, using flow cytometry, have reported a lower platelet reactivity in neonates compared to adults. Only few studies were carried out in older children, and results were controversial in terms of age to reach adult platelet function. We studied a total of 125 healthy neonates, infants and older children, and 15 adults. αIIbβ3 expression on resting and activated platelets was lower in all children, with an impaired capability of αIIbβ3 activation (PAC1 and bound fibrinogen). This defect was observed until the age of fifteen with a gradual recovery with age. In neonates, we observed a defect of GPIbα internalization, and demonstrated that this defect persisted in older children as well. In contrast with αIIbβ3 integrin activation, we did not observe a gradual age-dependent recovery. These unexpected results point out the need for reference values in childhood.

Effects of Ticlopidine of Platelet Function in Men with Stable Angina Pectoris

1985 ◽  
Vol 54 (04) ◽  
pp. 808-812 ◽  
Author(s):  
Ulf Berglund ◽  
Henning von Schenck ◽  
Lars Wallentin
Keyword(s):  
Platelet Aggregation ◽  
Angina Pectoris ◽  
Platelet Function ◽  
Plasma Levels ◽  
Platelet Reactivity ◽  
Inhibitory Effect ◽  
Controlled Study ◽  
Double Blind ◽  
Platelet Factor

SummaryThe effects of ticlopidine (T) (500 mg daily) on platelet function were investigated in a double-blind placebo-controlled study in 38 middle-aged men with stable incapacitating angina pectoris. The in vitro platelet reactivity to aggregating agents, the platelet sensitivity to prostacyclin and the plasma levels of platelet specific proteins and fibrinogen were determined before and after 4 and 8 weeks of treatment. T exerted a potent inhibitory effect on ADP- and collagen-induced platelet aggregation. The effect of T was proportional to the pretreatment reactivity to ADP and collagen. The inhibitory effect of T on the epinephrine response was less pronounced. The plasma levels of beta-thromboglobulin, platelet factor 4 and fibrinogen were not influenced by T. The platelet inhibition of prostacyclin was potentiated by T, and it was demonstrated that T and prostacyclin had synergistic inhibitory effects on platelet aggregation.

scholarly journals MicroRNA as Biomarkers for Platelet Function and Maturity in Patients with Cardiovascular Disease

2021 ◽  
Author(s):  
Oliver Buchhave Pedersen ◽  
Erik Lerkevang Grove ◽  
Steen Dalby Kristensen ◽  
Peter H. Nissen ◽  
Anne-Mette Hvas
Keyword(s):  
Cardiovascular Disease ◽  
Platelet Function ◽  
Assessment Tool ◽  
Platelet Reactivity ◽  
Thrombus Formation ◽  
Quality Assessment Tool ◽  
Treatment And Prevention ◽  
Increased Risk ◽  
Meta Analyses ◽  
Potential Use

AbstractPatients with cardiovascular disease (CVD) are at increased risk of suffering myocardial infarction. Platelets are key players in thrombus formation and, therefore, antiplatelet therapy is crucial in the treatment and prevention of CVD. MicroRNAs (miRs) may hold the potential as biomarkers for platelet function and maturity. This systematic review was conducted using the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). To identify studies investigating the association between miRs and platelet function and maturity in patients with CVD, PubMed and Embase were searched on October 13 and December 13, 2020 without time boundaries. Risk of bias was evaluated using a standardized quality assessment tool. Of the 16 included studies, 6 studies were rated “good” and 10 studies were rated “fair.” In total, 45 miRs correlated significantly with platelet function or maturity (rho ranging from –0.68 to 0.38, all p < 0.05) or differed significantly between patients with high platelet reactivity and patients with low platelet reactivity (p-values ranging from 0.0001 to 0.05). Only four miRs were investigated in more than two studies, namely miR-223, miR-126, miR-21 and miR-150. Only one study reported on the association between miRs and platelet maturity. In conclusion, a total of 45 miRs were associated with platelet function or maturity in patients with CVD, with miR-223 and miR-126 being the most frequently investigated. However, the majority of the miRs were only investigated in one study. More data are needed on the potential use of miRs as biomarkers for platelet function and maturity in CVD patients.

scholarly journals Evaluation of an Alternative Staining Method Using SYTO 13 to Determine Reticulated Platelets

2019 ◽  
Vol 119 (05) ◽  
pp. 779-785 ◽  
Author(s):  
Laura Hille ◽  
Marco Cederqvist ◽  
Julia Hromek ◽  
Christian Stratz ◽  
Dietmar Trenk ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Platelet Reactivity ◽  
Dependent Manner ◽  
Reticulated Platelets ◽  
Automated Assay ◽  
Rna Quantification ◽  
Time Period ◽  
Immature Platelet Fraction ◽  
Syto 13

AbstractReticulated platelets reflect the rate of platelet turnover and represent the youngest circulating platelets in peripheral blood. Reticulated platelets contain residual ribonucleic acid (RNA) from megakaryocytes which is lost in a time-dependent manner and can be transcribed into proteins even in the absence of a nucleus. An increased proportion of reticulated platelets is associated with higher platelet reactivity, cardiovascular events and mortality. At present, a fully automated assay system (SYSMEX haematology analyser) is available for analysis. This method, however, is not suitable for extended laboratory investigations like subsequent cell sorting. Flow cytometry analysis after staining with thiazole orange (TO) is frequently used in such settings despite several limitations. Here, we describe a new assay for determination of reticulated platelets by flow cytometry using the nucleic acid staining dye SYTO 13 and compare it with SYSMEX and TO staining as current standards. A significant correlation between immature platelet fraction (IPF) determined by SYSMEX XE-2100 analyser and results obtained with the SYTO 13-based assay was observed (r = 0.668, p < 0.001) which was stable during a reasonable time period. In contrast, the correlation between TO staining and IPF was weaker (r = 0.478, p = 0.029) and lost after 90 minutes of staining. SYTO 13 staining of platelets enabled sorting of RNAlow and RNArich platelets which was confirmed by RNA quantification of sorted platelets. Except for fixation of platelets, sorting of these platelet sub-populations was stable under various experimental settings. In summary, determination of reticulated platelets with the new SYTO 13 assay offers distinct technical advantages enabling further laboratory processing.

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