The effect of adding lactic acid to canine whole blood on platelet aggregation as measured by impedance aggregometry

2020 ◽  
Vol 49 (2) ◽  
pp. 217-221
Author(s):  
Cheryl A. Lawson ◽  
Elizabeth A. Spangler
Keyword(s):  
Lactic Acid ◽  
Platelet Aggregation ◽  
Whole Blood ◽  
Impedance Aggregometry

Effect of lactic acid addition to equine whole blood on platelet aggregation measured by impedance aggregometry

2022 ◽  
Author(s):  
Christopher J. Lanier ◽  
Jennifer S. Taintor ◽  
Peter W. Christopherson ◽  
Elizabeth A. Spangler
Keyword(s):  
Lactic Acid ◽  
Platelet Aggregation ◽  
Whole Blood ◽  
Acid Addition ◽  
Impedance Aggregometry

Comparison of Rapid Platelet Function Assay with Whole Blood Platelet Impedance Aggregometry for the Definition of Aspirin Resistance.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4018-4018
Author(s):  
Anna M. Dyszkiewicz-Korpanty ◽  
Anne Kim ◽  
James D. Burner ◽  
Eugene P. Frenkel ◽  
Ravindra Sarode
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Blood Platelet ◽  
Aspirin Resistance ◽  
Impedance Aggregometry ◽  
Definition Of ◽  
Induced Aggregation

Abstract The reported incidence of aspirin (ASA) resistance ranges from 5 to 30%. Various platelet function assays have been employed to detect aspirin resistance in patients with cardio- and cerebrovascular disease. Such a high proposed incidence of ASA resistance poses a critical need for a rapid point-of -care (POC) platelet function test. Unfortunately, no uniformly accepted definition of ASA resistance exists. Platelet aggregation studies that have been used to define ASA resistance are time consuming and require special technical expertise. The Ultegra Rapid Platelet Function -ASA (RPFA-ASA) has been developed as a POC test that is performed without sample processing. This optical method measures agglutination of fibrinogen-coated beads upon platelet activation with arachidonic acid. In the presence of aspirin effect, however, the agglutination of the beads is inhibited. The described cutoff of ≥ 550 Aspirin Reaction Units (ARU) is termed non-responsiveness to ASA based on a preclinical study and subsequent correlation with epinephrine-induced platelet aggregation in platelet rich plasma. Since RPFA-ASA uses whole blood, we validated its performance characteristics against a classic whole blood platelet aggregation assay (WBA). We studied 50 healthy volunteers, aged 25–75 (24 men, 26 women) with normal CBC, who had not ingested anti-platelet drugs for 14 days prior to the study. Baseline studies included WBA (dual channel aggregometer, Chrono-log Inc., Havertown, PA) using both arachidonic acid (AA -0.5; 0.25 mM) and collagen (1; 2 μg/mL) as well as an RPFA-ASA assay (Accumetrics Inc., San Diego, CA). These studies were repeated after 3 days of ASA (325 mg/d) intake. Based on a review of the literature, we defined an adequate ASA response as a completely inhibited AA-induced platelet aggregation and at least 30% inhibition of collagen-induced aggregation (both concentrations of the agonist). Thus, those with < 30% inhibition of aggregation response to collagen were considered ASA resistant. Eleven subjects were ASA resistant by WBA (20%; 8 females and 3 males (aged 25–63). In contrast, since all 50 subjects achieved ARU values of < 550 ARU, none were recognized as an ASA non-responder by the RPFA-ASA. While the current cutoff of < 550 ARU posed by the Ultegra RPFA-ASA does identify those who have taken ASA, the assay is unable to recognize ASA non-responders. Thus, based on these data, the appropriate cutoff for the recognition of ASA resistance by the RPFA-ASA should be re-adjusted to a significantly lower level to ensure appropriate assay results.

Abstract 336: Metabolites Reflecting Fresh Venous Thrombus: Lactic Acid and Guanine Enhance Whole Blood Coagulation

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Atsushi Yamashita ◽  
Chihiro Sugita ◽  
Sayaka Moriguchi-Goto ◽  
Eriko Nakamura ◽  
Kazunari Maekawa ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Platelet Aggregation ◽  
Blood Coagulation ◽  
Whole Blood ◽  
Thrombus Formation ◽  
Venous Blood ◽  
Blood Stasis ◽  
Adenosine Monophosphate ◽  
Venous Thrombus ◽  
Flight Mass Spectrometry

Background: Thrombus formation is a multicellular dynamic process involving platelets, leukocytes, and erythrocytes. Recent studies demonstrated that microemvironment affects cellular metabolism and that metabolites can alter the cellular function. The present study aims to identify metabolites reflecting fresh venous thrombus and their role on thrombus formation in rabbit. Methods: We performed metabolomic analysis of rabbit venous blood and jugular venous thrombus 4 hours after endothelial denudation and blood stasis using capillary electrophoresis-time of flight mass spectrometry. Effects of the altered metabolites on blood coagulation and platelet aggregation were assessed with rotation thromboelastometry and platelet aggregometer. Results: The metabolomics analysis identified 226 metabolites (133 cationic and 93 anionic metabolites) in the venous blood and thrombus. The levels of 7 or 4 of them were significantly more (thrombus/ blood ratio >5) or less (thrombus/ blood ratio <1/2) in thrombus than those in blood, and the metabolites included glycolysis, nucleotides, and redox-related metabolites. Three metabolites were detectable only in the blood or venous thrombus. Among the metabolites (thrombus/ blood ratio >5), lactic acid and guanine dose-dependently enhanced whole blood clotting with thromboelastometry. Adenosine monophosphate inhibited collagen-induced platelet aggregation. Conclusion: The glycolysis, nucleotides, and redox-related metabolites may reflect fresh venous thrombus, and lactic acid and guanine may enhance blood coagulation in venous thrombus formation. The metabolic change could provide new insight into the process of venous thrombus formation.

ADP-Induced Whole Blood Aggregometry and Platelet-Associated Thrombin Generation (TG) In Essential Thrombocythemia (ET) and Polycythemia Vera (PV) Patients

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1981-1981
Author(s):  
Marina Panova-Noeva ◽  
Marina Marchetti ◽  
Annamaria Leuzzi ◽  
Laura Russo ◽  
Guido Finazzi ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Thrombin Generation ◽  
Blood Platelet ◽  
Jak2v617f Mutation ◽  
Mutation Carriers ◽  
Impedance Aggregometry ◽  
Platelet Aggregometry ◽  
V617f Mutation ◽  
Blood Platelet Aggregation

Abstract Abstract 1981 Patients with ET and PV are characterized by an increased rate of thrombotic complications and by several abnormalities of platelets, more pronounced in JAK2V617F mutation carriers. Platelet function inhibitors are widely utilized for thromboprophylaxis in ET and PV patients. An increased reactivity to ADP of platelets from these patients has previously been shown by light transmission platelet aggregometry studies, which might explain the failure of aspirin to fully protect from thrombosis these patients, mainly those at high risk. While ADP activation pathway is critical for platelet aggregation, less is known about its role to the initiation of blood coagulation by platelets. In this study we wanted to evaluate in a group of patients with ET and PV, the platelet reactivity to ADP in terms of both proaggregating and procoagulant responses. ADP-induced platelet aggregation and platelet procoagulant potential (i.e. thrombin generation capacity) were measured by the whole blood impedance aggregometry (Multiplate analyser) and by the Calibrated Automated Thrombogram (CAT) assay, respectively. Whole blood platelet aggregation was induced by 6.5 μM ADP. Whereas thrombin generation (TG) was measured in platelet rich plasma (PRP: 150,000 platelets/μl) both in resting conditions and after stimulation by 1.6 μM and 8.3 μM ADP. Fifty patients with ET (58% V617F mutation carriers) and 40 patients with PV (95% V617F mutation carriers) were enrolled into the study. The results show that ET and PV patients presented with significantly higher ADP-induced whole blood platelet aggregation compared to control subjects (786±70 AU*min, and 777±54 AU*min, respectively, versus 465±70 AU*min, both p<0.05), the highest values being observed in ET and PV patients carriers of the JAK2V617F mutation (806±75 AU*min; p<0.001 vs controls). In resting conditions, TG in PRP from ET (133±38 nM) and PV (144±54 nM) patients was significantly greater compared to control PRP (103±21 nM; p<0.05). Similarly, in ADP-stimulated conditions, platelet TG was significantly higher (p<0.05) in ET and PV patients at both 1.6 μM ADP (140±32 nM and 154±59 nM; respectively) and 8.3 μM ADP (161±38 nM and 181±65 nM; respectively) compared to controls (1.6 μM ADP: 112±19 nM; 8.3 μM ADP: 132±26 nM). The analysis according to the JAK2 mutational status showed that platelets from JAK2V617F carriers induced significantly higher TG when stimulated by 8.3 μM ADP (185±47nM) compared to 1.6 μM ADP (146±45nM; p<0.001). Differently, this difference was not observed in JAK2 wild type patients. While in resting conditions patients on hydroxyurea (HU) generated less thrombin compared to non-HU treated patients, no effects of patients’ therapy on TG (i.e. aspirin, HU, aspirin+HU) was observed in the ADP-stimulated conditions. In conclusion, for the first time we demonstrated that platelets from ET and PV patients are more reactive to ADP, not only in terms of increased platelet aggregation in a whole blood system, but also as an enhanced thrombin generation, particularly in those carriers of JAK2V617F mutation. These data support the hypothesis that the use of ADP receptor-inhibitors, in addition to aspirin, might be of help in the prevention of thrombosis in these conditions, by allowing a more complete inhibition of platelet functions. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Cleavage of Anti-PF4/H IgG Antibodies By Ides, and Potential Benefit in the Treatment of Heparin-Induced Thrombocytopenia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 518-518
Author(s):  
Claire Kizlik-Masson ◽  
Quentin Deveuve ◽  
Yuhang Zhou ◽  
Caroline Vayne ◽  
Gilles Thibault ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Cell Activation ◽  
Conflicts Of Interest ◽  
Microfluidic Channels ◽  
Venous Flow ◽  
Platelet Factor ◽  
Cellular Activation ◽  
Heparin Induced Thrombocytopenia ◽  
Impedance Aggregometry

Abstract Heparin-induced thrombocytopenia (HIT) is a severe drug-adverse event due to platelet-activating antibodies (Abs) directed against platelet factor 4 (PF4)/heparin (H) complexes. In most patients, HIT Abs are IgG that directly activate platelets and monocytes in the presence of heparin via FcγRIIA receptors. The interaction between the Fc fragment of anti-PF4/H IgG and FcγRIIA is thus a key step for cellular activation in HIT. Several bacterial proteases such as IdeS (IgG-degrading enzyme of Streptococcus pyogenes) are cleaving IgG in the lower hinge region of heavy chain leading to the formation of single cleaved IgG (scIgG) and then of Fab'2. Importantly, cleavage of IgG by IdeS can abolish their ability to bind FcγR and suppress the cellular effects resulting from this interaction. The aim of this study was therefore to evaluate whether anti-PF4/H IgG cleavage by IdeS could inhibit cell activation induced by HIT antibodies, and their pathogenicity. To achieve this objective, we studied the effects of IdeS on platelet responses to 5B9, a monoclonal chimeric anti-PF4/H IgG1 recently developed in our laboratory, and which fully mimics the effects of human HIT antibodies (Kizlik-Masson et al, J Thromb Haemost, 2017). IdeS was demonstrated to quickly (6 minutes) cleave purified 5B9 IgG, leading to the formation of sc5B9, without any reduction in its binding ability to PF4/H complex. However, flow cytometry experiments showed that heparin-dependent binding of sc5B9 to platelets and FcγRIIA was dramatically reduced compared to those of uncleaved 5B9. In addition, functional assays (serotonin release assays and platelet aggregation tests) also confirmed that sc5B9 was unable to induce platelet activation and aggregation in the presence of heparin. Incubation of IdeS (0.02 U/µg of IgG; 6 minutes) in whole blood containing 5B9 IgG or HIT plasma samples also lead in every sample tested to the cleavage of anti-PF4/H Abs, which fully abolished their capacity to induce heparin-dependent platelet aggregation, as demonstrated by impedance aggregometry (Multiplate analyzer). As expected, no effect of IdeS was observed on platelet aggregation induced by collagen (1 µg/mL), or ADP (10 µM). Moreover, tissue factor (TF) gene expression induced in monocytes by 5B9 in the presence of heparin was also completely abolished after addition of IdeS (0.02 U/µg of IgG; 6 minutes) in whole blood, whereas no inhibitory effect of this protease on TF expression induced by LPS was evidenced. We also showed that platelet aggregation and fibrin formation induced by 5B9 with heparin was completely inhibited after IdeS treatment when whole blood was perfused in vWF-coated microfluidic channels with shear rates similar to those of venous flow (500s-1). Finally, IdeS was also showed to prevent efficiently thrombocytopenia and hypercoagulability (with no increase in thrombin/anti-thrombin plasma levels) induced by 5B9 in transgenic mice expressing human PF4 and FcγRIIA receptors, when previously treated by this protease (0.5 µg/g) before IV injection of heparin. In conclusion, the cleavage of anti-PF4/H IgG by IdeS prevents heparin-dependent cellular activation induced by HIT antibodies, thereby reducing their pathogenicity. Therefore, injection of IdeS could be considered as a potential treatment in patients with severe HIT, particularly in those who necessitate emergent cardiac surgery with cardiopulmonary bypass and thus anticoagulation with unfractionated heparin, which remains the safest and easiest anticoagulant to be used in this specific surgical procedure. Disclosures No relevant conflicts of interest to declare.

Complexes of Nitric Oxide with Nucleophiles as Agents for the Controlled Biological Release of Nitric Oxide: Antiplatelet Effect

1993 ◽  
Vol 70 (04) ◽  
pp. 654-658 ◽  
Author(s):  
Jean G Diodati ◽  
Arshed A Quyyumi ◽  
Nabeen Hussain ◽  
Larry K Keefer
Keyword(s):  
Nitric Oxide ◽  
Aqueous Solution ◽  
Platelet Aggregation ◽  
Sodium Nitroprusside ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Antiplatelet Agents ◽  
Platelet Inhibition ◽  
Impedance Aggregometry

SummaryNitric oxide (NO) inhibits platelet aggregation. Accordingly, we hypothesized that complexes of diethylamine and spermine with NO (DEA/NO and SPER/NO, respectively), two vasodilators previously shown to release NO spontaneously in aqueous solution, may also be useful antiplatelet agents. Platelet aggregation was measured in whole blood or platelet-rich plasma by impedance aggregometry after addition of collagen. In whole blood, the dose response curve for DEA/NO added 1 min before collagen was similar to that for aspirin (60% inhibition at 10-4 M), while SPER/NO and sodium nitroprusside were less potent by an order of magnitude. In platelet-rich plasma, 10-6 M DEA/NO caused 60% inhibition, while SPER/NO and sodium nitroprusside were as active only at 10-5 M; aspirin’s potency was unchanged from that in whole blood. In vivo, DEA/NO and sodium nitroprusside produced significant platelet inhibition 1 min after intravenous injection in the rabbit at 50 nmol/kg. Similar in vivo platelet inhibition was observed with SPER/NO and aspirin, but only at higher dose. The effects of DEA/NO and sodium nitroprusside were transient, lasting less than 30 min after treatment, while the activity of SPER/NO and aspirin was sustained throughout the 30 min experiment. The magnitude and duration of the antiplatelet effects of DEA/NO and SPER/NO correlate with the rates at which they release nitric oxide spontaneously in aqueous solution. Thus, NO/nucleophile complexes merit further exploration both as research tools and as potential antiplatelet agents.

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