Prediction of Antiplatelet Effects of Aspirin In Vivo Based on In Vitro Results

Yokoyama, Hiroyuki; Ito, Naoko; Soeda, Shinji; Ozaki, Masahiro; Suzuki, Yuji; Watanabe, Masayuki; Kashiwakura, Emiko; Kawada, Tsutomu; Ikeda, Noriyuki; Tokuoka, Kentaro; Kitagawa, Yasuhisa; Yamada, Yasuhiko

doi:10.1177/1076029613484084

Cited by 6 publications

(5 citation statements)

References 15 publications

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“…S3B–D , Supplementary Table S1 [online only]). 24 27 28 P2Y 12 and PAR1 inhibition significantly suppressed MPA formation by 30 and 21%, respectively ( p < 0.01 for each comparison, Fig. 3C ), with MPA reductions consistent across monocyte subtypes ( Supplementary Fig.…”

Section: Resultsmentioning

confidence: 85%

“…S3B-D, ►Supplementary Table S1 [online only]). 24,27,28 Activated platelets are characterized by increased surface expression of P-selectin (α-granule release) and PAC-1 (activated GP IIb/IIIa). As expected, stimulation of whole blood with U-46619 increased platelet expression of P-selectin and PAC-1 (►Supplementary Fig.…”

Section: Platelets Induce a Proinflammatory Transcriptome In Monocytesmentioning

confidence: 99%

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P2Y12 Inhibition Suppresses Proinflammatory Platelet–Monocyte Interactions

et al. 2023

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Background Monocyte–platelet aggregates (MPAs) represent the crossroads between thrombosis and inflammation, and targeting this axis may suppress thromboinflammation. While antiplatelet therapy (APT) reduces platelet–platelet aggregation and thrombosis, its effects on MPA and platelet effector properties on monocytes are uncertain. Objectives To analyze the effect of platelets on monocyte activation and APT on MPA and platelet-induced monocyte activation. Methods Agonist-stimulated whole blood was incubated in the presence of P-selectin, PSGL1, PAR1, P2Y12, GP IIb/IIIa, and COX-1 inhibitors and assessed for platelet and monocyte activity via flow cytometry. RNA-Seq of monocytes incubated with platelets was used to identify platelet-induced monocyte transcripts and was validated by RT-qPCR in monocyte-PR co-incubation ± APT. Results Consistent with a proinflammatory platelet effector role, MPAs were increased in patients with COVID-19. RNA-Seq revealed a thromboinflammatory monocyte transcriptome upon incubation with platelets. Monocytes aggregated to platelets expressed higher CD40 and tissue factor than monocytes without platelets (p < 0.05 for each). Inhibition with P-selectin (85% reduction) and PSGL1 (87% reduction) led to a robust decrease in MPA. P2Y12 and PAR1 inhibition lowered MPA formation (30 and 21% reduction, p < 0.05, respectively) and decreased monocyte CD40 and TF expression, while GP IIb/IIIa and COX1 inhibition had no effect. Pretreatment of platelets with P2Y12 inhibitors reduced the expression of platelet-mediated monocyte transcription of proinflammatory SOCS3 and OSM. Conclusions Platelets skew monocytes toward a proinflammatory phenotype. Among traditional APTs, P2Y12 inhibition attenuates platelet-induced monocyte activation.

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Section: Resultsmentioning

confidence: 85%

Section: Platelets Induce a Proinflammatory Transcriptome In Monocytesmentioning

confidence: 99%

P2Y12 Inhibition Suppresses Proinflammatory Platelet–Monocyte Interactions

et al. 2023

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“…As COX‐1 exists in a dimeric form, a coefficient greater than one would be indicated to show positive cooperative binding. For this study, the Hill coefficient was set at 2.1 as was used in previous studies (Haines et al., ; Yokoyama et al., ).…”

Section: Methodsmentioning

confidence: 99%

Investigation into the causes of aspirin resistance in healthy dogs

Haines

Lee

Hegedus

et al. 2018

Vet Pharm & Therapeutics

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Antiplatelet effects of acetylsalicylic acid (ASA, aspirin) may be poor in some individuals. Additionally, no method exists for predicting poor ASA response (resistance) in individual dogs. This study's main objective was to determine whether poor ASA response results from pharmacodynamic or pharmacokinetic causes. ASA concentrations causing 50% inhibition of platelet aggregation (in vitro IC50) were determined using whole blood collected from 21 drug‐free healthy dogs to evaluate intrinsic sensitivity of platelets to ASA. Dogs were then administered ASA at 4 mg/kg once orally. Percent decrease in platelet aggregation from baseline, and plasma ASA and salicylic acid (SA) concentrations (expressed as AUC values) were measured for up to 3 hr. By 3 hr, 13/21 (62%) dogs showed >50% aggregation inhibition, while 8/21 (38%) dogs showed <50% inhibition. Aggregation inhibition values were negatively correlated with in vitro IC50 values (Rs = −0.49; p = 0.028) and positively correlated with ASA concentrations (Rs = 0.48; p = 0.03). Furthermore, ASA concentrations were strongly negatively correlated (Rs = −0.88; p < 0.001) with SA/ASA concentration ratios, an index of ASA metabolism to SA by esterase enzymes. Multiple linear regression analysis indicated that 59% (p < 0.001) of interindividual variability in aggregation inhibition was explained by in vitro IC50 values (29% of variability) and ASA concentrations (29% of variability). Consequently, poor in vivo ASA response in these dogs resulted from both pharmacodynamic (decreased platelet sensitivity) and pharmacokinetic (lower ASA concentrations) causes. Lower ASA concentrations may be explained by reduced bioavailability associated with higher esterase activities.

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“…If a dog did not show > 50% inhibition at the concentrations used in this study (16‐555 μmol/L), this equation also allowed for extrapolation of an expected IC50 value. In this equation, Emax is the maximum inhibition of platelet aggregation (%), E is the extent of aggregation inhibition, IC50 is the 50% inhibitory concentration ( μmol/L), C is drug concentration ( μmol/L), γ is the Hill coefficient which was set at 2.1 to reflect the dimeric form of COX‐1 as recommended previously (Yokoyama et al., ).

E = false(E_{\max} \times C^{γ} false) / false({EC}_{50}^{γ} + C^{γ} false)

…”

Section: Methodsmentioning

confidence: 99%

“…Secondly, we wanted to develop an in vitro method for determining the ASA IC50 in healthy dog blood using Multiplate impedance platelet aggregometry. The use of blood samples collected from human patients and incubated with ASA has been shown to allow determination of an IC50 through the use of LTA (Weber, Przytulski, Schanz, Hohlfeld, & Schror, ; Yokoyama et al., ). We hypothesized that this same method would also allow for determination of an IC50 for ASA in dogs using the Multiplate analyzer.…”

Section: Introductionmentioning

confidence: 99%

Establishment of reference ranges and evaluation of in vitro concentration‐dependent platelet inhibition by acetylsalicylic acid for multiple electrode impedance aggregometry in healthy dogs

Haines

Lee

Hegedus

et al. 2017

Vet Pharm & Therapeutics

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Acetylsalicylic acid (ASA, aspirin) is an antiplatelet medication used for prevention of thromboembolism. Effects of ASA appear to vary widely between dogs, but the underlying mechanisms are not understood. The Multiplate analyzer is a newer form of whole-blood impedance aggregometry recently validated for use in healthy dogs. A method utilizing this instrument to measure ASA effects on platelet function has not been established. The goals of this study were to establish reference ranges for the Multiplate in healthy dogs and secondly, to develop a technique to determine the in vitro concentration of ASA needed to cause 50% inhibition of platelet aggregation (IC50). Reference ranges established from 40 dogs at multiple test times for three agonists were consistent with previously published values. In vitro IC50 values were calculated using the sigmoid E model in 20 healthy dogs on two occasions to determine individual repeatability. Calculated in vitro IC50 demonstrated four ASA response groups: responder (n = 16), poor responder (n = 1), variable responder (n = 2), and nonresponder (n = 1). Multiplate within-assay variability was <10% for area under the curve (AUC), and between-assay baseline AUC variability was <15%. The described technique allowed for determination of an in vitro IC50 for ASA in dogs using a multiple electrode impedance aggregometer.

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Prediction of Antiplatelet Effects of Aspirin In Vivo Based on In Vitro Results

Cited by 6 publications

References 15 publications

P2Y12 Inhibition Suppresses Proinflammatory Platelet–Monocyte Interactions

P2Y12 Inhibition Suppresses Proinflammatory Platelet–Monocyte Interactions

Investigation into the causes of aspirin resistance in healthy dogs

Establishment of reference ranges and evaluation of in vitro concentration‐dependent platelet inhibition by acetylsalicylic acid for multiple electrode impedance aggregometry in healthy dogs

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