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Heimgartner LM, Stirn M, Kutter APN, Sigrist NE, Jud Schefer R. Whole blood platelet impedance aggregometry with the ROTEM platelet device: comparison of 2 anticoagulants and storage times for the establishment of canine reference intervals. J Vet Diagn Invest 2021; 34:15-22. [PMID: 34654336 DOI: 10.1177/10406387211051329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The ROTEM platelet device, a point-of-care whole blood platelet impedance aggregometer, is an add-on to the rotational thromboelastometry ROTEM delta device. The latter has been validated in dogs. We examined whether canine whole blood is suited for analysis with the ROTEM platelet device using adenosine-5'-diphosphate (ADP) and arachidonic acid (ARA) as agonists for platelet activation, and if there are significant differences between sample storage times and anticoagulants used. Subsequently, we determined canine reference intervals (RIs) for the ROTEM platelet device for ADP and ARA. In a pilot study, we examined whole blood from 7 dogs after 15-min and 60-min storage of lithium-heparinized samples and 40-min and 80-min storage of hirudinized samples. Statistical analysis showed no significant differences between ROTEM platelet device results for both ADP and ARA in lithium-heparin and hirudin anticoagulated canine whole blood. Lithium-heparinized blood samples analyzed after 15-min storage had the lowest coefficient of variation. RIs were determined for heparinized whole blood samples from 49 dogs after 15 min of storage.
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Affiliation(s)
- Lara M Heimgartner
- Division of Emergency and Critical Care Medicine, Department of Small Animals, Vetsuisse Faculty of the University of Zurich, Zurich, Switzerland
| | - Martina Stirn
- Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty of the University of Zurich, Zurich, Switzerland
| | - Annette P N Kutter
- Section of Anaesthesiology, Department for Clinical Diagnostics and Services, Vetsuisse Faculty of the University of Zurich, Zurich, Switzerland
| | - Nadja E Sigrist
- Division of Emergency and Critical Care Medicine, Department of Small Animals, Vetsuisse Faculty of the University of Zurich, Zurich, Switzerland
| | - Rahel Jud Schefer
- Division of Emergency and Critical Care Medicine, Department of Small Animals, Vetsuisse Faculty of the University of Zurich, Zurich, Switzerland
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Thomason JM, Archer TM, Wills RW, Mackin AJ. Effects of pentoxifylline on canine platelet aggregation. Vet Med Sci 2021; 7:2178-2184. [PMID: 34358418 PMCID: PMC8604144 DOI: 10.1002/vms3.595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Pentoxifylline can decrease platelet function in humans, but the anti-platelet effects of pentoxifylline in dogs is unknown. The addition of a luciferin-luciferase reagent during platelet aggregometry can induce a dose-dependent potentiation of platelet aggregation. OBJECTIVE To determine if exposure to pentoxifylline, without the addition of a luciferin-luciferase reagent during aggregometry, causes canine platelet dysfunction. Our hypotheses were that pentoxifylline would inhibit platelet function, and that the addition of a luciferin-luciferase reagent would obscure detection of pentoxifylline-induced platelet dysfunction as measured via aggregometry. METHODS Seven healthy Walker hound dogs. Platelet-rich plasma (PRP) and whole blood were treated for 30 minutes with pentoxifylline: 0 (control), 1 and 2 μg/mL. The platelet aggregation was determined using optical (maximum amplitude) and impedance (ohms) aggregometry using collagen as the agonists, with and without a luciferin-luciferase reagent. Four samples were analysed per concentration and the results were averaged. RESULTS Based on optical aggregometry, there was no difference (p = 0.964) in the mean maximum amplitude at any pentoxifylline concentration, with and without the luciferin-luciferase reagent. During impedance aggregometry, the addition of a luciferin-luciferase reagent was associated with significantly (p < 0.001) greater platelet aggregation in response to a collagen agonist, regardless of the presence or absence of pentoxifylline. CONCLUSIONS Pentoxifylline does not exert an in vitro anti-platelet effect on canine platelet aggregation when collagen is used as an agonist, but it is unknown if long-term oral drug administration will inhibit platelet aggregation. The addition of a luciferin-luciferase reagent during platelet aggregometry can artificially enhance canine platelet aggregation.
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Affiliation(s)
- John M Thomason
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, Mississippi
| | - Todd M Archer
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, Mississippi
| | - Robert W Wills
- Department of Comparative Biomedical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, Mississippi
| | - Andrew J Mackin
- Department of Clinical Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, Mississippi
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Significant differences in single-platelet biophysics exist across species but attenuate during clot formation. Blood Adv 2021; 5:432-437. [PMID: 33496738 DOI: 10.1182/bloodadvances.2020003755] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 12/06/2020] [Indexed: 12/14/2022] Open
Abstract
Key Points
Human, canine, ovine, and porcine platelets exhibit disparate biophysical signatures, whereas human and murine platelets are similar. Multiple biophysical parameters integrate during clot formation, measured by bulk clot contraction, and attenuate biophysical differences.
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Cao J, Yang P, Wang P, Xu S, Cheng Y, Qian K, Xu M, Sheng D, Li Y, Wei Y, Zhang Q. 'Adhesion and release' nanoparticle-mediated efficient inhibition of platelet activation disrupts endothelial barriers for enhanced drug delivery in tumors. Biomaterials 2020; 269:120620. [PMID: 33421709 DOI: 10.1016/j.biomaterials.2020.120620] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 12/10/2020] [Accepted: 12/17/2020] [Indexed: 12/14/2022]
Abstract
Activated platelets can maintain tumor vessel integrity, thereby leading to limited tumor perfusion and suboptimal antitumor efficacy of nanoparticle-based drugs. Herein, to disrupt the tumor vascular endothelial barriers by inhibiting the transformation of resting platelets to activated platelets, a TM33 peptide-modified gelatin/oleic acid nanoparticle loaded with tanshinone IIA (TNA) was constructed (TM33-GON/TNA). TM33-GON/TNA could adhere to activated platelets by specifically binding their superficial P-selectin and release TNA into the extracellular space under matrix metalloproteinase-2 (MMP-2) stimulation, leading to local high TNA exposure. Thus, platelet activation, adhesion, and aggregation, which occur in the local environment around the activated platelets, were efficiently inhibited, leading to leaky tumor endothelial junctions. Accordingly, TM33-GON/TNA treatment resulted in a 3.2-, 4.0-, and 11.2-fold increase in tumor permeation of Evans blue (macromolecule marker), small-sized Nab-PTX (~10 nm), and large-sized DOX-Lip (~100 nm), respectively, without elevating drug delivery to normal tissues. Ultimately, TM33-GON/TNA plus Nab-PTX exhibited superior antitumor efficacy with minimal side effects in a murine pancreatic cancer model. In addition, the TM33-GON/TNA-induced disrupted endothelial junctions were reversibly restored after the treatment because the number of platelets was not reduced, which implies a low risk of the undesirable systemic bleeding. Hence, TM33-GON/TNA represents a clinically translational adjuvant therapy to magnify the antitumor efficacy of existing nanomedicines in pancreatic cancer and other tumors with tight endothelial lining.
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Affiliation(s)
- Jinxu Cao
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Peng Yang
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Pengzhen Wang
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Shuting Xu
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Yunlong Cheng
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Kang Qian
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Minjun Xu
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Dongyu Sheng
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Yixian Li
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Yan Wei
- Institute of Translational Medicine, Shanghai University, Shanghai, 200436, China.
| | - Qizhi Zhang
- Key Laboratory of Smart Drug Delivery, Ministry of Education, School of Pharmacy, Fudan University, Shanghai, 201203, China.
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Gant P, McBride D, Humm K. Abnormal platelet activity in dogs and cats - impact and measurement. J Small Anim Pract 2020; 61:3-18. [PMID: 31919851 DOI: 10.1111/jsap.13092] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 05/06/2019] [Accepted: 10/28/2019] [Indexed: 01/08/2023]
Abstract
Abnormal platelet activity can either lead to bleeding tendencies or inappropriate thrombus formation and can occur secondarily to a wide variety of disease processes, with a range of clinical consequences and severity. This article will discuss the pathophysiology of platelet function abnormalities and consider a logical diagnostic approach applicable to veterinary practice. Recent advances in platelet function testing will then be discussed, with regards to detection of platelet dysfunction and tailoring of pharmacological manipulation. Although many of these tests are still confined to research or academic institutions, techniques for indirectly assessing platelet function are starting to become more widely available. Although we still require further research to develop guidelines for the use of these tests in clinical decision-making, the recent advances in this field are an exciting step forward in being able to detect and manage platelet dysfunction in both primary care and referral practice.
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Affiliation(s)
- P Gant
- Queen Mother Hospital for Animals (QMHA), The Royal Veterinary College, Hatfield, Hertfordshire, AL9 7TA, UK
| | - D McBride
- Queen Mother Hospital for Animals (QMHA), The Royal Veterinary College, Hatfield, Hertfordshire, AL9 7TA, UK
| | - K Humm
- Queen Mother Hospital for Animals (QMHA), The Royal Veterinary College, Hatfield, Hertfordshire, AL9 7TA, UK
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Saati S, Abrams‐Ogg A, Blois S, Wood R. Comparison of Multiplate, Platelet Function Analyzer-200, and Plateletworks in Healthy Dogs Treated with Aspirin and Clopidogrel. J Vet Intern Med 2018; 32:111-118. [PMID: 29194772 PMCID: PMC5787169 DOI: 10.1111/jvim.14886] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 09/23/2017] [Accepted: 10/23/2017] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Platelet function testing may be warranted to assess response to aspirin and clopidogrel. HYPOTHESIS/OBJECTIVES To evaluate the effects of aspirin, clopidogrel, or combination therapy using 3 platelet function tests: Multiplate Analyzer (MP), Platelet Function Analyzer-200 (PFA), and Plateletworks (PW). ANIMALS Six healthy laboratory Beagles. METHODS Randomized double-blind placebo-controlled study (crossover design). Dogs were given aspirin 1 mg/kg, clopidogrel 2 mg/kg, or combination therapy for 1 week each, with a washout period of 2 weeks. Platelet function was assessed on days 0 and 7 of each phase using MP (adenosine diphosphate [ADP], arachidonic acid [AA], collagen [COL] agonists), PFA (P2Y, COL-ADP [CADP], COL-Epinephrine [CEPI] cartridges), and PW (ADP, AA, COL agonists). Platelet counts were obtained with impedance and optical counters. RESULTS For MP, mean aggregation was decreased for COL and AA with combination therapy and for ADP with all treatments. For PFA, mean CT was increased for the CEPI cartridge with aspirin; and for the P2Y and CADP cartridges with clopidogrel or combination therapy. More dogs receiving clopidogrel showed an increase in PFA CT using the P2Y than the CADP cartridge. For PW, mean aggregation was decreased for AA with all treatments; for ADP with clopidogrel or combination therapy; and for COL with clopidogrel. The PW results with the 2 hematology counters showed almost perfect agreement. CONCLUSION AND CLINICAL IMPORTANCE All platelet function tests detected treatment effects in some dogs and may have utility for monitoring therapy.
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Affiliation(s)
- S. Saati
- Department of Clinical StudiesOntario Veterinary CollegeUniversity of GuelphGuelphONCanada
| | - A.C.G. Abrams‐Ogg
- Department of Clinical StudiesOntario Veterinary CollegeUniversity of GuelphGuelphONCanada
| | - S.L. Blois
- Department of Clinical StudiesOntario Veterinary CollegeUniversity of GuelphGuelphONCanada
| | - R.D. Wood
- Department of PathobiologyOntario Veterinary CollegeUniversity of GuelphGuelphONCanada
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Dunning M, May J, Adamany J, Heptinstall S, Fox S. A Remote Assay for Measuring Canine Platelet Activation and the Inhibitory Effects of Antiplatelet Agents. J Vet Intern Med 2017; 32:119-127. [PMID: 29197128 PMCID: PMC5787215 DOI: 10.1111/jvim.14845] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 06/16/2017] [Accepted: 08/28/2017] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Antiplatelet medications are increasingly used in dogs. Remote analysis of platelet activity is challenging, limiting assessment of antiplatelet drug efficacy. HYPOTHESIS/OBJECTIVES To evaluate a method used in humans for stimulation and remote analysis of canine platelet activity. ANIMALS Forty-five dogs of various ages without a coagulopathy or thrombocytopenia. Six were receiving antiplatelet medication. METHODS Prospective 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. RESULTS Canine 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 IMPORTANCE This 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.
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Affiliation(s)
- M Dunning
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK
| | - J May
- Clinical Neuroscience, Queen's Medical Centre, Nottingham, UK
| | - J Adamany
- Pride Veterinary Centre, Derbyshire, UK
| | - S Heptinstall
- Clinical Neuroscience, Queen's Medical Centre, Nottingham, UK
| | - S Fox
- Clinical Neuroscience, Queen's Medical Centre, Nottingham, UK
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Haines JM, Lee PM, Hegedus RM, Hwang JK, Court MH. Establishment of reference ranges and evaluation of in vitro concentration-dependent platelet inhibition by acetylsalicylic acid for multiple electrode impedance aggregometry in healthy dogs. J Vet Pharmacol Ther 2017; 40:618-628. [PMID: 28387027 DOI: 10.1111/jvp.12405] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/23/2017] [Indexed: 11/30/2022]
Abstract
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 Emax 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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Affiliation(s)
- J M Haines
- Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - P M Lee
- Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - R M Hegedus
- Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - J K Hwang
- Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - M H Court
- Program in Individualized Medicine (PrIMe), Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
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