1
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Tunströmer K, Faxälv L, Larsson P, Lindahl TL, Boknäs N. Thrombus remodelling by reversible and irreversible P2Y 12 inhibitors. Platelets 2023; 34:2157805. [PMID: 36631918 DOI: 10.1080/09537104.2022.2157805] [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: 01/13/2023]
Abstract
Pharmacological inhibition of the platelet ADP-receptor P2Y12 is a cornerstone in the prevention of atherothrombotic events in adult patients with acute coronary syndrome (ACS). Thienopyridines such as clopidogrel and prasugrel exert their antithrombotic effect by means of active metabolites that irreversibly inhibit P2Y12. Due to the short half-life of these metabolites, a subpopulation of ADP-responsive platelets will form in between dosing. With increased platelet turnover rate or poor patient compliance, the fraction of ADP-responsive platelets will increase, potentially increasing the risk for new thrombotic events. In contrast, the reversible P2Y12 inhibition produced by direct-acting ADP blockers such as ticagrelor and cangrelor inhibit the entire platelet population. In this study, we evaluated the impact of these pharmacological differences on thrombus formation in an ex vivo flow chamber model. A customized image analysis pipeline was used for automatized, large-scale identification and tracking of single platelets incorporated into the thrombus, enabling quantitative analysis of the relative contribution of inhibited and uninhibited platelets to thrombus growth and consolidation. Comparative experiments were conducted using the irreversible and reversible P2Y12 inhibitors prasugrel active metabolite (PAM) and ticagrelor, respectively. Our results show that PAM inhibited thrombus platelet recruitment more gradually than ticagrelor, with a slower onset of inhibition. Further, we show that the presence of a small fraction (<10%) of uninhibited platelets did not abrogate the antithrombotic effect of PAM to any significant extent. Finally, we demonstrate a gradual enrichment of inhibited platelets in the thrombus shell due to selective recruitment of inhibited platelets to the thrombus periphery.
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Affiliation(s)
- Kjersti Tunströmer
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Lars Faxälv
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Pia Larsson
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.,Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - Tomas L Lindahl
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.,Department of Clinical Chemistry and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Niklas Boknäs
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.,Department of Hematology and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
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2
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Vadlamani VMK, Gunasinghe KKJ, Chee XW, Rahman T, Harper MT. Human soluble CD39 displays substrate inhibition in a substrate-specific manner. Sci Rep 2023; 13:8958. [PMID: 37268726 DOI: 10.1038/s41598-023-36257-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/31/2023] [Indexed: 06/04/2023] Open
Abstract
CD39 (ectonucleoside triphosphate diphosphohydrolase-1; ENTPD1) metabolizes extracellular ATP and ADP to AMP. AMP is subsequently metabolized by CD79 to adenosine. CD39 activity is therefore a key regulator of purinergic signalling in cancer, thrombosis, and autoimmune diseases. In this study we demonstrate that soluble, recombinant CD39 shows substrate inhibition with ADP or ATP as the substrate. Although CD39 activity initially increased with increasing substrate concentration, at high concentrations of ATP or ADP, CD39 activity was markedly reduced. Although the reaction product, AMP, inhibits CD39 activity, insufficient AMP was generated under our conditions to account for the substrate inhibition seen. In contrast, inhibition was not seen with UDP or UTP as substrates. 2-methylthio-ADP also showed no substrate inhibition, indicating the nucleotide base is an important determinant of substrate inhibition. Molecular dynamics simulations revealed that ADP can undergo conformational rearrangements within the CD39 active site that were not seen with UDP or 2-methylthio-ADP. Appreciating the existence of substrate inhibition of CD39 will help the interpretation of studies of CD39 activity, including investigations into drugs that modulate CD39 activity.
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Affiliation(s)
- Venkat M K Vadlamani
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | | | - Xavier W Chee
- Swinburne University of Technology Sarawak, Kuching, Malaysia
| | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Matthew T Harper
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK.
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3
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Crossen J, Shankar KN, Diamond SL. Investigating thrombin-loaded fibrin in whole blood clot microfluidic assay via fluorogenic peptide. Biophys J 2023; 122:697-712. [PMID: 36635963 PMCID: PMC9989883 DOI: 10.1016/j.bpj.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/19/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
During clotting under flow, thrombin rapidly generates fibrin, whereas fibrin potently sequesters thrombin. This co-regulation was studied using microfluidic whole blood clotting on collagen/tissue factor, followed by buffer wash, and a start/stop cycling flow assay using the thrombin fluorogenic substrate, Boc-Val-Pro-Arg-AMC. After 3 min of clotting (100 s-1) and 5 min of buffer wash, non-elutable thrombin activity was easily detected during cycles of flow cessation. Non-elutable thrombin was similarly detected in plasma clots or arterial whole blood clots (1000 s-1). This thrombin activity was ablated by Phe-Pro-Arg-chloromethylketone (PPACK), apixaban, or Gly-Pro-Arg-Pro to inhibit fibrin. Reaction-diffusion simulations predicted 108 nM thrombin within the clot. Heparin addition to the start/stop assay had little effect on fibrin-bound thrombin, whereas addition of heparin-antithrombin (AT) required over 6 min to inhibit the thrombin, indicating a substantial diffusion limitation. In contrast, heparin-AT rapidly inhibited thrombin within microfluidic plasma clots, indicating marked differences in fibrin structure and functionality between plasma clots and whole blood clots. Addition of GPVI-Fab to blood before venous or arterial clotting (200 or 1000 s-1) markedly reduced fibrin-bound thrombin, whereas GPVI-Fab addition after 90 s of clotting had no effect. Perfusion of AF647-fibrinogen over washed fluorescein isothiocyanate (FITC)-fibrin clots resulted in an intense red layer around, but not within, the original FITC-fibrin. Similarly, introduction of plasma/AF647-fibrinogen generated substantial red fibrin masses that did not penetrate the original green clots, demonstrating that fibrin cannot be re-clotted with fibrinogen. Overall, thrombin within fibrin is non-elutable, easily accessed by peptides, slowly accessed by average-sized proteins (heparin/AT), and not accessible to fresh fibrinogen.
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Affiliation(s)
- Jennifer Crossen
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | - Kaushik N Shankar
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | - Scott L Diamond
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104.
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4
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Whyte CS, Mutch NJ. “Going with the flow” in modeling fibrinolysis. Front Cardiovasc Med 2022; 9:1054541. [DOI: 10.3389/fcvm.2022.1054541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022] Open
Abstract
The formation of thrombi is shaped by intravascular shear stress, influencing both fibrin architecture and the cellular composition which has downstream implications in terms of stability against mechanical and fibrinolytic forces. There have been many advancements in the development of models that incorporate flow rates akin to those found in vivo. Both thrombus formation and breakdown are simultaneous processes, the balance of which dictates the size, persistence and resolution of thrombi. Therefore, there is a requirement to have models which mimic the physiological shear experienced within the vasculature which in turn influences the fibrinolytic degradation of the thrombus. Here, we discuss various assays for fibrinolysis and importantly the development of novel models that incorporate physiological shear rates. These models are essential tools to untangle the molecular and cellular processes which govern fibrinolysis and can recreate the conditions within normal and diseased vessels to determine how these processes become perturbed in a pathophysiological setting. They also have utility to assess novel drug targets and antithrombotic drugs that influence thrombus stability.
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5
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Trigani KT, DeCortin M, Diamond S. ADP and thromboxane inhibitors both reduce global contraction of clot length, while thromboxane inhibition attenuates internal aggregate contraction. TH OPEN 2022; 6:e135-e143. [PMID: 35707619 PMCID: PMC9192180 DOI: 10.1055/a-1832-9293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 04/14/2022] [Indexed: 11/10/2022] Open
Abstract
Platelet contractility drives clot contraction to enhance clot density and stability. Clot contraction is typically studied under static conditions, with fewer studies of wall-adherent platelet clots formed under flow. We tested the effect of inhibitors of ADP and/or thromboxane A2 (TXA2) signaling on clot contraction. Using an eight-channel microfluidic device, we perfused PPACK-treated whole blood (WB) ± acetylsalicylic acid (ASA), 2-methylthioAMP (2-MeSAMP), and/or MRS-2179 over collagen (100/s) for 7.5 min, then stopped flow to observe contraction for 7.5 minutes. Two automated imaging methods scored fluorescent platelet percent contraction over the no-flow observation period: (1) “global” measurement of clot length and (2) “local” changes in surface area coverage of the numerous platelet aggregates within the clot. Total platelet fluorescence intensity (FI) decreased with concomitant decrease in global aggregate contraction when ASA, 2-MeSAMP, and/or MRS-2179 were present. Total platelet FI and global aggregate contraction were highly correlated (
R2
= 0.87). In contrast, local aggregate contraction was more pronounced than global aggregate contraction across all inhibition conditions. However, ASA significantly reduced local aggregate contraction relative to conditions without TXA2 inhibition. P-selectin display was significantly reduced by ADP and TXA2 inhibition, but there was limited detection of global or local aggregate contraction in P-selectin-positive platelets across all conditions, as expected for densely packed “core” platelets. Our results demonstrate that global aggregate contraction is inhibited by ASA, 2-MeSAMP, and MRS-2179, while ASA more potently inhibited local aggregate contraction. These results help resolve how different platelet antagonists affect global and local clot structure and function.
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Affiliation(s)
- Kevin Timothy Trigani
- Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, United States
| | - Michael DeCortin
- Chemical & Biomolecular Engineering, University of Pennsylvania, Philadelphia, United States
| | - Scott Diamond
- Institute for Medicine and Engineering, U Penn Vagelos Research Laboratories, Philadelphia, United States
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6
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Berry J, Harper MT. Protease-activated receptor antagonists prevent thrombosis when dual antiplatelet therapy is insufficient in an occlusive thrombosis microfluidic model. Res Pract Thromb Haemost 2022; 6:e12703. [PMID: 35434469 PMCID: PMC9001860 DOI: 10.1002/rth2.12703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/11/2022] [Accepted: 03/08/2022] [Indexed: 11/23/2022] Open
Abstract
Background Platelet activation and arterial thrombosis on a ruptured atherosclerotic plaque is a major cause of myocardial infarction. Dual antiplatelet therapy (DAPT), the combination of platelet aggregation inhibitors, aspirin and a P2Y12 antagonist, is used to prevent arterial thrombosis. However, many people continue to have arterial thrombosis and myocardial infarction despite DAPT, indicating that additional therapies are required where DAPT is insufficient. Objectives To determine whether antagonists of protease-activated receptors (PARs) can prevent occlusive thrombosis under conditions where DAPT is insufficient. Methods We used human whole blood in a microfluidic model of occlusive thrombosis to compare conditions under which DAPT is effective to those under which DAPT was not. Cangrelor (a P2Y12 antagonist) and aspirin were used to mimic DAPT. We then investigated whether the PAR1 antagonist vorapaxar or the PAR4 antagonist BMS 986120, alone or in combination with DAPT, prevented occlusive thrombosis. Results and Conclusions A ruptured plaque exposes collagen fibers and is often rich in tissue factor, triggering activation of platelets and coagulation. Occlusive thrombi formed on type I collagen in the presence or absence of tissue factor (TF). However, although DAPT prevented occlusive thrombosis in the absence of TF, DAPT had little effect when TF was also present. Under these conditions, PAR antagonism was also ineffective. However, occlusive thrombosis was prevented by combining DAPT with PAR antagonism. These data demonstrate that PAR antagonists may be a useful addition to DAPT in some patients and further demonstrate the utility of in vitro models of occlusive thrombosis.
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Affiliation(s)
- Jess Berry
- Department of PharmacologyUniversity of CambridgeCambridgeUK
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7
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Continuum modeling of thrombus formation and growth under different shear rates. J Biomech 2022; 132:110915. [PMID: 35032838 DOI: 10.1016/j.jbiomech.2021.110915] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 01/18/2023]
Abstract
Obstruction of blood flow due to thrombosis is a major cause of ischemic stroke, myocardial infarction, and in severe cases, mortality. In particular, in blood wetting medical devices, thrombosis is a common reason for failure. The prediction of thrombosis by understanding signaling pathways using computational models, lead to identify the risk of thrombus formation in blood-contacting devices and design improvements. In this study, a mathematical model of thrombus formation and growth is presented. A biochemical model of platelet activation and aggregation is developed to predict thrombus size and shape at the site of vascular injury. Computational fluid dynamics using the finite volume method is employed to compute the velocity and pressure fields which are influenced by the growing thrombi. The passive transport of platelets, agonists, the platelet activation kinetics, their adhesion to the growing thrombi and embolization of platelets are solved by a fully coupled set of convection-diffusion-reaction equations. The thrombogenic surface representing blood-contacting material or injured blood vessel was incorporated into the model as a surface flux boundary condition to initiate thrombus formation. The blood is considered as a Newtonian fluid, while the thrombus is treated as a porous medium. The results are compared with in vitro experiments of a microfluidic chamber at an initial inlet venous shear rate of 200s-1 using a pressure-inlet boundary condition. The thrombus development due to agonist concentrations and change in the shear rate as well as thromboembolism for this benchmark problem is successfully computed. Furthermore, to extend the current model to a physiologically relevant configuration, thrombus formation in a blood tube is simulated. Two different heterogeneous reaction rates for platelet aggregation are used to simulate thrombus growth under a constant inlet flow rate. The findings show that the thrombus shape can be substantially altered by the hemodynamic conditions, increase in the shear rate and due to the combined effects of shear induced platelet activation and the heterogeneous reaction rates. It is also concluded that the model is able to predict thrombus formation in different physiological and pathological hemodynamics.
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8
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Diamond SL, Rossi JM. Point of care whole blood microfluidics for detecting and managing thrombotic and bleeding risks. LAB ON A CHIP 2021; 21:3667-3674. [PMID: 34476426 PMCID: PMC8478847 DOI: 10.1039/d1lc00465d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Point-of-care diagnostics of platelet and coagulation function present demanding challenges. Current clinical diagnostics often use centrifuged plasmas or platelets and frozen plasma standards, recombinant protein standards, or even venoms. Almost all commercialized tests of blood do not recreate the in vivo hemodynamics where platelets accumulate to high densities and thrombin is generated from a procoagulant surface. Despite numerous drugs that target platelets, insufficient coagulation, or excess coagulation, POC blood testing is essentially limited to viscoelastic methods that provide a clotting time, clot strength, and clot lysis, while used mostly in trauma centers with specialized capabilities. Microfluidics now allows small volumes of whole blood (<1 mL) to be tested under venous or arterial shear rates with multi-color readouts to follow platelet function, thrombin generation, fibrin production, and clot stability. Injection molded chips containing pre-patterned fibrillar collagen and lipidated tissue factor can be stored dry for 6 months at 4C, thus allowing rapid blood testing on single-use disposable chips. Using only a small imaging microscope and micropump, these microfluidic devices can detect platelet inhibitors, direct oral anticoagulants (DOACs) and their reversal agents. POC microfluidics are ideal for neonatal surgical applications that involve small blood samples, rapid DOAC testing in stroke or bleeding or emergency surgery situations with patients presenting high risk cofactors for either bleeding or thrombosis.
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Affiliation(s)
- Scott L Diamond
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 1024 Vagelos Research Laboratory, Philadelphia, PA 19104, USA.
| | - Jason M Rossi
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 1024 Vagelos Research Laboratory, Philadelphia, PA 19104, USA.
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9
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Leiderman K, Sindi SS, Monroe DM, Fogelson AL, Neeves KB. The Art and Science of Building a Computational Model to Understand Hemostasis. Semin Thromb Hemost 2021; 47:129-138. [PMID: 33657623 PMCID: PMC7920145 DOI: 10.1055/s-0041-1722861] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Computational models of various facets of hemostasis and thrombosis have increased substantially in the last decade. These models have the potential to make predictions that can uncover new mechanisms within the complex dynamics of thrombus formation. However, these predictions are only as good as the data and assumptions they are built upon, and therefore model building requires intimate coupling with experiments. The objective of this article is to guide the reader through how a computational model is built and how it can inform and be refined by experiments. This is accomplished by answering six questions facing the model builder: (1) Why make a model? (2) What kind of model should be built? (3) How is the model built? (4) Is the model a “good” model? (5) Do we believe the model? (6) Is the model useful? These questions are answered in the context of a model of thrombus formation that has been successfully applied to understanding the interplay between blood flow, platelet deposition, and coagulation and in identifying potential modifiers of thrombin generation in hemophilia A.
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Affiliation(s)
- Karin Leiderman
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, Colorado
| | - Suzanne S Sindi
- Department of Applied Mathematics, University of California, Merced, Merced, California
| | - Dougald M Monroe
- Department of Medicine, UNC Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Aaron L Fogelson
- Departments of Mathematics and Biomedical Engineering, University of Utah, Salt Lake City, Utah
| | - Keith B Neeves
- Department of Bioengineering, Department of Pediatrics, Section of Hematology, Oncology, and Bone Marrow Transplant, Hemophilia and Thrombosis Center, University of Colorado, Denver, Colorado
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10
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Roka-Moiia Y, Miller-Gutierrez S, Palomares DE, Italiano JE, Sheriff J, Bluestein D, Slepian MJ. Platelet Dysfunction During Mechanical Circulatory Support: Elevated Shear Stress Promotes Downregulation of α IIbβ 3 and GPIb via Microparticle Shedding Decreasing Platelet Aggregability. Arterioscler Thromb Vasc Biol 2021; 41:1319-1336. [PMID: 33567867 DOI: 10.1161/atvbaha.120.315583] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Yana Roka-Moiia
- Department of Medicine (Y.R.-M., S.M.-G.), Sarver Heart Center, University of Arizona, Tucson
| | - Samuel Miller-Gutierrez
- Department of Medicine (Y.R.-M., S.M.-G.), Sarver Heart Center, University of Arizona, Tucson
| | - Daniel E Palomares
- Department of Biomedical Engineering (D.E.P., M.J.S.), Sarver Heart Center, University of Arizona, Tucson
| | - Joseph E Italiano
- Brigham and Woman's Hospital, Harvard Medical School, Boston, MA (J.E.I.)
| | - Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY (J.S., D.B., M.J.S.)
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY (J.S., D.B., M.J.S.)
| | - Marvin J Slepian
- Department of Biomedical Engineering (D.E.P., M.J.S.), Sarver Heart Center, University of Arizona, Tucson.,Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY (J.S., D.B., M.J.S.)
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11
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Vargas D, Zhou H, Yu X, Diamond S, Yeh J, Allada V, Krishnamurthy G, Price M, Allen B, Alexander J, Schmidhofer J, Kreutzer J, Vincent J, Morell V, Bacha E, Diacovo T. Cangrelor PK/PD analysis in post-operative neonatal cardiac patients at risk for thrombosis. J Thromb Haemost 2021; 19:202-211. [PMID: 33078501 DOI: 10.1111/jth.15141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/07/2020] [Accepted: 10/12/2020] [Indexed: 01/18/2023]
Abstract
Essentials An optimal therapeutic strategy has yet to be established to prevent early shunt thrombosis. A phase 1 study of cangrelor was performed in neonates after palliation of congenital heart disease. PD endpoint of >90% platelet inhibition in 60% of patients was achieved at 0.5 µg/kg/min dosing. No serious adverse events related to drug administration were observed, including bleeding. ABSTRACT: Background Systemic-to-pulmonary artery shunt thrombosis is a significant cause of early postoperative mortality in neonates after palliation of congenital heart disease. In the context of thromboprophylaxis, an optimal therapeutic strategy has yet to be established before aspirin administration. Cangrelor, a fast-acting, reversible P2Y12 inhibitor, may fill this unmet need. Objectives To evaluate the pharmacokinetics (PK), pharmacodynamics (PD), and safety of cangrelor in neonates undergoing stage 1 palliation. Methods This prospective, open-label, single-arm study evaluated two cangrelor dosing cohorts following placement of a systemic-to-pulmonary artery shunt, right ventricle-to-pulmonary artery shunt, or ductal stent. Drug concentrations and platelet reactivity, assessed by light transmission aggregometry and in microfluidic assays (MF), were measured. Results Twenty-two patients were consented and 15 received a 1-hour infusion of cangrelor at either 0.5 µg/kg/min (cohort 1) or 0.25 µg/kg/min (cohort 2). Whereas the primary PD endpoint was achieved at the higher dose (ie, reduction in maximal platelet aggregation by ≥90% in 60% of participants), only 29% of those in cohort 2 attained this goal. Comparable and statistically significant results were obtained in MF assays (P < .0001 vs. baseline). Drug levels during infusion were 3-fold higher in cohort 1 vs. cohort 2 (P < .001). Most participants (70%) had undetectable drug levels by 10 minutes postinfusion with full recovery in platelet function at 1 hour. No drug-related bleeding events occurred. Conclusions Favorable PK/PD properties of cangrelor 0.5 µg/kg/min dosing and safety profile warrant further evaluation in neonates following palliative cardiac procedures.
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Affiliation(s)
- Diana Vargas
- Department of Pediatrics, Columbia University Medical Center, New York, NY, USA
| | - Hairu Zhou
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Xinren Yu
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Scott Diamond
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Justin Yeh
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Vivekanand Allada
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ganga Krishnamurthy
- Department of Pediatrics, Columbia University Medical Center, New York, NY, USA
| | | | | | | | - Joseph Schmidhofer
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Jacqueline Kreutzer
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Julie Vincent
- Department of Pediatrics, Columbia University Medical Center, New York, NY, USA
| | - Victor Morell
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Emile Bacha
- Department of Surgery, Columbia University School of Medicine, New York, NY, USA
| | - Thomas Diacovo
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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12
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Trigani KT, Diamond SL. Intrathrombus Fibrin Attenuates Spatial Sorting of Phosphatidylserine Exposing Platelets during Clotting Under Flow. Thromb Haemost 2020; 121:46-57. [PMID: 32961573 DOI: 10.1055/s-0040-1715648] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND As thrombosis proceeds, certain platelets in a clot expose phosphatidylserine (PS) on their outer membrane. These PS+ platelets subsequently sort to the perimeter of the mass via platelet contraction. It remains unclear how thrombin and fibrin may alter PS+ platelet sorting within a clot. OBJECTIVE We investigated the role of fibrin in PS+ platelet sorting. METHODS We used an 8-channel microfluidic assay of clotting over collagen (±tissue factor) at 100 s-1 initial wall shear rate. Temporal PS+ platelet sorting was measured using a Pearson's correlation coefficient between the annexin V distribution in a clot at 9 versus 15 minutes. Spatial PS+ platelet sorting was measured using an autocorrelation metric of the final annexin V distribution. RESULTS By 6 minutes, PS+ platelets were distributed throughout the platelet deposits and became highly spatially sorted by 15 minutes when thrombin and fibrin were blocked with Phe-Pro-Arg-chloromethylketone (PPACK). Fibrin polymerization (no PPACK) attenuated temporal and spatial PS sorting and clot contraction. With Gly-Pro-Arg-Pro (GPRP) added to block fibrin polymerization, PS sorting was prominent as was clot contraction. Exogenously added tissue plasminogen activator drove fibrinolysis that in turn promoted clot contraction and PS sorting, albeit to a lesser degree than the PPACK or GPRP conditions. Clots lacking fibrin displayed 3.6 times greater contraction than clots with fibrin. CONCLUSION PS sorting correlated with clot contraction, as previously reported. However, fibrin inversely correlated with both percent contraction and PS sorting. Fibrin attenuated clot contraction and PS sorting relative to clots without fibrin.
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Affiliation(s)
- Kevin T Trigani
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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13
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Rossi JM, Diamond SL. Scalable manufacture of a disposable, storage-stable eight-channel microfluidic device for rapid testing of platelet, coagulation, and drug function under whole blood flow. BIOMICROFLUIDICS 2020; 14:054103. [PMID: 33014235 PMCID: PMC7527242 DOI: 10.1063/5.0023312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/17/2020] [Indexed: 05/04/2023]
Abstract
Custom polydimethylsiloxane (PDMS) microfluidic devices allow for small-volume human blood research under hemodynamic conditions of bleeding and clotting. However, issues of PDMS molding/assembly, bio-coating, and sample preparation often limit their point-of-care use. We aim to develop a microfluidic device that has the same utility as previously established PDMS devices but which is more usable in point-of-care operation. We designed an injection-molded 1 × 3 in.2 device with eight flow paths crossing a bio-printed surface of a collagen/tissue factor. The device is rapidly primed and compatible with multi-channel pipetting (<0.5 ml blood) and operates under venous or arterial shear rates using constant flow rate or constant pressure modes. Platelet and fibrin deposition were monitored dynamically by the imaging of immunofluorescence. For whole blood clotting at a wall shear rate of 200 s-1, the intrachip CV at 400 s for platelet and fibrin deposition was 10% and the interdonor CV at 400 s was 30% for platelet and 22% for fibrin deposition (across 10 healthy donors). No significant difference was detected for samples tested on a new chip vs a chip stored for 6 months at 4 °C. Using the fibrin signal, dose-response testing of whole blood revealed IC50's of 120 nM for rivaroxaban and apixaban, and 60 nM for dabigatran. A complete reversal of apixaban inhibition was observed for an equimolar addition of Xa DOAC reversal agent Andexanet Alfa. We demonstrate the ability to manufacture single-use, storage-stable eight-channel chips. In clinical settings, such chips may help evaluate patient bleeding risk, therapy choice, drug activity, or reversal.
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Affiliation(s)
| | - Scott L. Diamond
- Author to whom correspondence should be addressed:. Tel.: +1 215 573 5704. Fax: +1 215 573 6815
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Zhang Y, Diamond SL. Src family kinases inhibition by dasatinib blocks initial and subsequent platelet deposition on collagen under flow, but lacks efficacy with thrombin generation. Thromb Res 2020; 192:141-151. [PMID: 32480168 DOI: 10.1016/j.thromres.2020.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/24/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Abstract
Kinase inhibitors can pose bleeding risks as platelet signaling evolves during clotting. Using microfluidics (200 s-1 wall shear rate) to perfuse Factor XIIa-inhibited or thrombin-inhibited whole blood (WB) over collagen ± tissue factor (TF), we explored the potency of the Src family kinase (SFK) inhibitor dasatinib or the spleen tyrosine kinase (Syk) inhibitor GS-9973 present at clot initiation or added after 90 s (via rapid switch to inhibitor-pretreated WB). When initially present, dasatinib potently inhibited platelet deposition on collagen (no TF). Furthermore, dasatinib immediately inhibited subsequent platelet deposition when introduced 90 s after clot initiation. However, when thrombin was generated, dasatinib was markedly less potent against platelet deposition on collagen/TF (but blocked fibrin deposition) and had no effect when added 90 s after clot initiation. Similarly, dasatinib added at 90 s had no effect on clotting on collagen/TF when fibrin was also blocked with Gly-Pro-Arg-Pro, indicating that strong thrombin-induced signaling (but not fibrin-induced signaling) can bypass the SFK inhibition at later times. The Syk inhibitor GS-9973 was less potent than dasatinib when present initially, but inhibited clot growth when added at 90 s, even in the presence of thrombin (±fibrin). Interestingly, the active form (R-406) of fostamatinib inhibits platelet function in only 2 0f 5 healthy blood samples. SFK-inhibitors may have reduced antithrombotic activity and reduced bleeding risks in settings of high TF and local thrombin generation. For oncology patients, SFK-inhibitors like dasatinib may have reduced antithrombotic activity and reduced bleeding risk in settings of local thrombin generation.
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Affiliation(s)
- Yiyuan Zhang
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Platelet Adhesion and Thrombus Formation in Microchannels: The Effect of Assay-Dependent Variables. Int J Mol Sci 2020; 21:ijms21030750. [PMID: 31979370 PMCID: PMC7037340 DOI: 10.3390/ijms21030750] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/13/2020] [Accepted: 01/21/2020] [Indexed: 12/12/2022] Open
Abstract
Microfluidic flow chambers (MFCs) allow the study of platelet adhesion and thrombus formation under flow, which may be influenced by several variables. We developed a new MFC, with which we tested the effects of different variables on the results of platelet deposition and thrombus formation on a collagen-coated surface. Methods: Whole blood was perfused in the MFC over collagen Type I for 4 min at different wall shear rates (WSR) and different concentrations of collagen-coating solutions, keeping blood samples at room temperature or 37 °C before starting the experiments. In addition, we tested the effects of the antiplatelet agent acetylsalicylic acid (ASA) (antagonist of cyclooxygenase-1, 100 µM) and cangrelor (antagonist of P2Y12, 1 µM). Results: Platelet deposition on collagen (I) was not affected by the storage temperature of the blood before perfusion (room temperature vs. 37 °C); (II) was dependent on a shear rate in the range between 300/s and 1700/s; and (III) was influenced by the collagen concentration used to coat the microchannels up to a value of 10 µg/mL. ASA and cangrelor did not cause statistically significant inhibition of platelet accumulation, except for ASA at low collagen concentrations. Conclusions: Platelet deposition on collagen-coated surfaces is a shear-dependent process, not influenced by the collagen concentration beyond a value of 10 µg/mL. However, the inhibitory effect of antiplatelet drugs is better observed using low concentrations of collagen.
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Yu X, Panckeri KA, Ivanciu L, Camire RM, Coxon CH, Cuker A, Diamond SL. Microfluidic hemophilia models using blood from healthy donors. Res Pract Thromb Haemost 2020; 4:54-63. [PMID: 31989085 PMCID: PMC6971334 DOI: 10.1002/rth2.12286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 10/18/2019] [Accepted: 10/28/2019] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Microfluidic clotting assays permit drug action studies for hemophilia therapeutics under flow. However, limited availability of patient samples and Inter-donor variability limit the application of such assays, especially with many patients on prophylaxis. OBJECTIVE To develop approaches to phenocopy hemophilia using modified healthy blood in microfluidic assays. METHODS Corn trypsin inhibitor (4 µg/mL)-treated healthy blood was dosed with either anti-factor VIII (FVIII; hemophilia A model) or a recombinant factor IX (FIX) missense variant (FIX-V181T; hemophilia B model). Treated blood was perfused at 100 s-1 wall shear rate over collagen/tissue factor (TF) or collagen/factor XIa (FXIa). RESULTS Anti-FVIII partially blocked fibrin production on collagen/TF, but completely blocked fibrin production on collagen/FXIa, a phenotype reversed with 1 µmol/L bispecific antibody (emicizumab), which binds FIXa and factor X. As expected, emicizumab had no significant effect on healthy blood (no anti-FVIII present) perfused over collagen/FXIa. The efficacy of emicizumab in anti-FVIII-treated healthy blood phenocopied the action of emicizumab in the blood of a patient with hemophilia A perfused over collagen/FXIa. Interestingly, a patient-derived FVIII-neutralizing antibody reduced fibrin production when added to healthy blood perfused over collagen/FXIa. For low TF surfaces, reFIX-V181T (50 µg/mL) fully blocked platelet and fibrin deposition, a phenotype fully reversed with anti-TFPI. CONCLUSION Two new microfluidic hemophilia A and B models demonstrate the potency of anti-TF pathway inhibitor, emicizumab, and a patient-derived inhibitory antibody. Using collagen/FXIa-coated surfaces resulted in reliable and highly sensitive hemophilia models.
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Affiliation(s)
- Xinren Yu
- Department of Chemical and Biomolecular EngineeringInstitute for Medicine and EngineeringUniversity of PennsylvaniaPhiladelphiaPennsylvania
| | - Karen A. Panckeri
- Penn Comprehensive Hemophilia and Thrombosis ProgramHospital of the University of PennsylvaniaPhiladelphiaPennsylvania
| | - Lacramioara Ivanciu
- The Raymond G. Perelman Center for Cellular and Molecular TherapeuticsThe Children’s Hospital of PhiladelphiaPhiladelphiaPennsylvania
- Division of HematologyDepartment of PediatricsPerelman School of MedicineThe University of PennsylvaniaPhiladelphiaPennsylvania
| | - Rodney M. Camire
- The Raymond G. Perelman Center for Cellular and Molecular TherapeuticsThe Children’s Hospital of PhiladelphiaPhiladelphiaPennsylvania
- Division of HematologyDepartment of PediatricsPerelman School of MedicineThe University of PennsylvaniaPhiladelphiaPennsylvania
| | - Carmen H. Coxon
- National Institute for Biological Standards and ControlPotters BarUK
| | - Adam Cuker
- Penn Comprehensive Hemophilia and Thrombosis ProgramHospital of the University of PennsylvaniaPhiladelphiaPennsylvania
| | - Scott L. Diamond
- Department of Chemical and Biomolecular EngineeringInstitute for Medicine and EngineeringUniversity of PennsylvaniaPhiladelphiaPennsylvania
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Loyau S, Ho-Tin-Noé B, Bourrienne MC, Boulaftali Y, Jandrot-Perrus M. Microfluidic Modeling of Thrombolysis. Arterioscler Thromb Vasc Biol 2019; 38:2626-2637. [PMID: 30354249 DOI: 10.1161/atvbaha.118.311178] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective- Despite the high clinical relevance of thrombolysis, models for its study in human flowing blood are lacking. Our objective was to develop a microfluidic model for comparative evaluation of thrombolytic therapeutic strategies. Approach and Results- Citrated human blood was supplemented with 3,3'-dihexyloxacarbocyanine iodide and Alexa Fluor 647 fibrinogen conjugate, recalcified, and perfused for 3 to 4 minutes at venous or arterial wall shear rate in microfluidic flow chambers coated with collagen and tissue factor to generate nonocclusive fluorescent thrombi. A second perfusion was performed for 10 minutes with rhodamine-6G-labeled citrated whole blood, supplemented or not with r-tPA (recombinant tissue-type plasminogen activator), fluorescein isothiocyanate-conjugated r-tPA, and Alexa Fluor 568 plasminogen conjugate. Plasminogen and r-tPA bound to preformed thrombi and r-tPA caused a concentration-dependent decrease in thrombus fibrin content (up to 50% reduction at 15 µg/mL r-tPA) as assessed by fluorescence microscopy. Fibrinolysis was confirmed by measurement of D-dimers in the output flow. Remarkably, despite ongoing fibrinolysis, new platelets continued to be recruited to the thrombus under lysis. Under the arterial condition, combining r-tPA with hirudin enhanced fibrinolysis but did not prevent the recruitment of new platelets, which was, however, prevented by antiplatelet agents (ticagrelor or the GPVI [glycoprotein VI]-blocking antigen-binding fragment 9O12). Conclusions- Our microfluidic thrombolysis model is suitable for studying thrombolysis and testing the efficacy of drugs used in combination with r-tPA. Real-time analysis of fibrin and platelets during r-tPA-mediated fibrinolysis at arterial or venous flow conditions showed that platelets continue to accumulate during fibrinolysis. Such platelet accumulation may impair r-tPA-mediated recanalization.
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Affiliation(s)
- Stéphane Loyau
- From the INSERM, University Paris Diderot (S.L., B.H.-T.-N., Y.B., M.J.-P.), U1148, Laboratory for Vascular Translational Science, Paris, France
| | - Benoit Ho-Tin-Noé
- From the INSERM, University Paris Diderot (S.L., B.H.-T.-N., Y.B., M.J.-P.), U1148, Laboratory for Vascular Translational Science, Paris, France
| | - Marie-Charlotte Bourrienne
- Department of Hematology, Bichat Hospital (M.-C.B.), U1148, Laboratory for Vascular Translational Science, Paris, France
| | - Yacine Boulaftali
- From the INSERM, University Paris Diderot (S.L., B.H.-T.-N., Y.B., M.J.-P.), U1148, Laboratory for Vascular Translational Science, Paris, France
| | - Martine Jandrot-Perrus
- From the INSERM, University Paris Diderot (S.L., B.H.-T.-N., Y.B., M.J.-P.), U1148, Laboratory for Vascular Translational Science, Paris, France
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Microfluidic and computational study of structural properties and resistance to flow of blood clots under arterial shear. Biomech Model Mechanobiol 2019; 18:1461-1474. [PMID: 31055691 PMCID: PMC6748893 DOI: 10.1007/s10237-019-01154-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 04/20/2019] [Indexed: 01/01/2023]
Abstract
The ability of a blood clot to modulate blood flow is determined by the clot’s resistance, which depends on its structural features. For a flow with arterial shear, we investigated the characteristic patterns relating to clot shape, size, and composition on the one hand, and its viscous resistance, intraclot axial flow velocity, and shear distributions on the other. We used microfluidic technology to measure the kinetics of platelet, thrombin, and fibrin accumulation at a thrombogenic surface coated with collagen and tissue factor (TF), the key clot-formation trigger. We subsequently utilized the obtained data to perform additional calibration and validation of a detailed computational fluid dynamics model of spatial clot growth under flow. We then ran model simulations to gain insights into the resistance of clots formed under our experimental conditions. We found that increased thrombogenic surface length and TF surface density enhanced the bulk thrombin and fibrin generation in a nonadditive, synergistic way. The height of the platelet deposition domain—and, therefore, clot occlusivity—was rather robust to thrombogenic surface length and TF density variations, but consistently increased with time. Clot viscous resistance was non-uniform and tended to be higher in the fibrin-rich, inner “core” region of the clot. Interestingly, despite intraclot structure and viscous resistance variations, intraclot flow velocity variations were minor compared to the abrupt decrease in flow velocity around the platelet deposition region. Our results shed new light on the connection between the structure of clots under arterial shear and spatiotemporal variations in their resistance to flow.
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Yu X, Diamond SL. Fibrin Modulates Shear-Induced NETosis in Sterile Occlusive Thrombi Formed under Haemodynamic Flow. Thromb Haemost 2019; 119:586-593. [PMID: 30722079 DOI: 10.1055/s-0039-1678529] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Neutrophils can release extracellular traps (NETs) in infectious, inflammatory and thrombotic diseases. NETs have been detected in deep vein thrombosis, atherothrombosis, stroke, disseminated intravascular coagulation and trauma. We have previously shown that haemodynamic forces trigger rapid NETosis within sterile occlusive thrombi in vitro. Here, we tested the effects of thrombin, fibrin and fibrinolysis on shear-induced NETosis by imaging NETs with Sytox Green during microfluidic perfusion of factor XIIa-inhibited or thrombin-inhibited human whole blood over fibrillar collagen (±tissue factor). For perfusions under venous pressure drops (19 mm Hg/mm-clot), thrombin generation did not alter the near-zero level of NET generation. In contrast, production of thrombin/fibrin led to a twofold reduction in neutrophil accumulation and a sixfold reduction in NET generation after 30 minutes of arterial perfusion (163 mm Hg/mm-clot). Exogenously added tissue type plasminogen activator (tPA) drove robust fibrinolysis; however, tPA did not trigger NETosis under venous flow. In contrast, tPA did enhance NET generation in clots subjected to arterial pressure drops. After 45 minutes of arterial perfusion, clots treated with 30 nM tPA had a threefold increase in total NET production and a twofold increase in normalized NET generation (measured as deoxyribonucleic acid:neutrophil) compared with fibrin-rich clots. Blocking fibrin polymerization resulted in similar level of NET release seen in tPA-treated clots, whereas ε-aminocaproic acid abolished the NET-enhancing effect of tPA. Therefore, fibrin suppresses NET generation and the absence of fibrin promotes NETs. We demonstrated that shear-induced NETosis was strongly inversely correlated with fibrin in sterile occlusive clots.
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Affiliation(s)
- Xinren Yu
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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Brass LF, Tomaiuolo M, Welsh J, Poventud-Fuentes I, Zhu L, Diamond SL, Stalker TJ. Hemostatic Thrombus Formation in Flowing Blood. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00020-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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21
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Lu Y, Lee MY, Zhu S, Sinno T, Diamond SL. Multiscale simulation of thrombus growth and vessel occlusion triggered by collagen/tissue factor using a data-driven model of combinatorial platelet signalling. MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA 2018; 34:523-546. [PMID: 27672182 PMCID: PMC5798174 DOI: 10.1093/imammb/dqw015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 08/23/2016] [Indexed: 12/23/2022]
Abstract
During clotting under flow, platelets bind and activate on collagen and release autocrinic factors such as ADP and thromboxane, while tissue factor (TF) on the damaged wall leads to localized thrombin generation. Towards patient-specific simulation of thrombosis, a multiscale approach was developed to account for: platelet signalling [neural network (NN) trained by pairwise agonist scanning (PAS), PAS-NN], platelet positions (lattice kinetic Monte Carlo, LKMC), wall-generated thrombin and platelet-released ADP/thromboxane convection–diffusion (partial differential equation, PDE) and flow over a growing clot (lattice Boltzmann). LKMC included shear-driven platelet aggregate restructuring. The PDEs for thrombin, ADP and thromboxane were solved by finite element method using cell activation-driven adaptive triangular meshing. At all times, intracellular calcium was known for each platelet by PAS-NN in response to its unique exposure to local collagen, ADP, thromboxane and thrombin. When compared with microfluidic experiments of human blood clotting on collagen/TF driven by constant pressure drop, the model accurately predicted clot morphology and growth with time. In experiments and simulations at TF at 0.1 and 10 molecule-TF/\documentclass[12pt]{minimal}
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}{}$_{1}$\end{document} and IP-receptor. This multiscale approach facilitates patient-specific simulation of thrombosis under hemodynamic and pharmacological conditions.
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Affiliation(s)
- Yichen Lu
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Mei Yan Lee
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Shu Zhu
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Talid Sinno
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia PA 19104, USA
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Tunströmer K, Faxälv L, Boknäs N, Lindahl TL. Quantification of Platelet Contractile Movements during Thrombus Formation. Thromb Haemost 2018; 118:1600-1611. [PMID: 30112750 PMCID: PMC6298232 DOI: 10.1055/s-0038-1668151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Imaging methods based on time-lapse microscopy are important tools for studying the dynamic events that shape thrombus formation upon vascular injury. However, there is a lack of methods to translate the vast amount of visual data generated in such experiments into quantitative variables describing platelet movements that can be subjected to systematic analysis. In this study, we developed experimental and computational protocols allowing for a detailed mathematical analysis of platelet movements within a developing thrombus. We used a flow chamber-based model of thrombosis wherein a collagen strip was used to initiate platelet adhesion and activation. Combining the use of a platelet staining protocol, designed to enable identification of individual platelets, and image processing, we tracked the movements of a large number of individual platelets during thrombus formation and consolidation. These data were then processed to generate aggregate measures describing the heterogeneous movements of platelets in different areas of the thrombus and at different time points. Applying this model and its potential, to a comparative analysis on a panel of platelet inhibitors, we found that total platelet intra-thrombus movements are only slightly reduced by blocking the interactions between glycoproteins IIb/IIIa and Ib and their ligands or by inhibiting thromboxane synthesis or P2Y12 signalling. In contrast, whereas 30 to 40% of the platelets movements (for the CD42a-labelled platelets) and 20% (for the pro-coagulant platelets), within a thrombus, are contractile, i.e., towards the centre of the thrombus, this contractile component is almost totally abolished in the presence of agents inhibiting these pathways.
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Affiliation(s)
- Kjersti Tunströmer
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Lars Faxälv
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Niklas Boknäs
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Department of Haematology, Linköping University, Linköping, Sweden
| | - Tomas L Lindahl
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Department of Clinical Chemistry, Linköping University, Linköping, Sweden
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Quantifying Embolism: Label‐Free Volumetric Mapping of Thrombus Structure and Kinesis in a Microfluidic System with Optical Holography. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/adbi.201800089] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Chen J, Verni CC, Jouppila A, Lassila R, Diamond SL. Dual antiplatelet and anticoagulant (APAC) heparin proteoglycan mimetic with shear-dependent effects on platelet-collagen binding and thrombin generation. Thromb Res 2018; 169:143-151. [PMID: 30071479 DOI: 10.1016/j.thromres.2018.07.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/28/2018] [Accepted: 07/24/2018] [Indexed: 11/16/2022]
Abstract
Heparin proteoglycans (HEP-PGs) carry standard heparin-mediated anticoagulant properties as well as novel antiplatelet functions, a combination that may be significant for targeting multiple pathways in a single therapy. Recent work developing semisynthetic HEP-PG mimetics has shown promising results also in vivo, however flow conditions in vitro that replicate in vivo hemodynamics have not been reported. In this work, we present several assays (platelet calcium mobilization, aggregometry, microfluidic tests at venous and arterial hemodynamics) to characterize specific mechanistic effects of dual antiplatelet and anticoagulant (APAC) constructs as mimetics of HEP-PGs. Three APACs with different conjugation levels of heparin chains (CL10, CL18, HICL) were shown to decrease platelet deposition to collagen surfaces in PPACK-treated whole blood at venous shear rate (200 s-1). FXIIa-inhibited whole blood (CTI: corn trypsin inhibitor, 40 μg/mL) perfused over collagen/tissue factor showed reduced both platelet and fibrin deposition when treated with APACs. IC50 values for platelet and fibrin inhibition were calculated for each molecule at venous shear rate. Increasing the shear rate to arterial flows (1000 s-1) and using APAC as the sole anticoagulant, resulted in a more potent antiplatelet effect of APAC, suggesting an added effect on von Willebrand Factor (vWF) function. Additionally, APAC caused an inhibition of calcium mobilization specific to thrombin and collagen stimulation and a dose-dependent reduction in collagen-mediated platelet aggregation. Understanding the sensitivity of APAC activity to shear rate, platelet signaling and procoagulant pathways is important for applications in which APAC administration may have beneficial therapeutic effects.
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Affiliation(s)
- Jason Chen
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Christopher C Verni
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Annukka Jouppila
- Helsinki University Central Hospital Research Institute, Helsinki, Finland
| | - Riitta Lassila
- Coagulation Disorders Unit, University of Helsinki, Departments of Hematology and Clinical Chemistry (HUSLAB Laboratory Services), Comprehensive Cancer Center, Helsinki University Hospital, Helsinki, Finland; Aplagon Oy, Helsinki, Finland
| | - Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA.
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Zhu S, Herbig BA, Yu X, Chen J, Diamond SL. Contact Pathway Function During Human Whole Blood Clotting on Procoagulant Surfaces. Front Med (Lausanne) 2018; 5:209. [PMID: 30083534 PMCID: PMC6064720 DOI: 10.3389/fmed.2018.00209] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 07/02/2018] [Indexed: 11/13/2022] Open
Abstract
Microfluidic thrombosis assays allow the control of anticoagulation, hemodynamics, pharmacology, and procoagulant surfaces containing collagen ± tissue factor (TF). With corn trypsin inhibitor (CTI) ranging from low (1–4 μg/mL) to high levels (40–60 μg/mL), the function of Factor XIIa (FXIIa) can be modulated in the presence of low or high surface TF. With high CTI and no collagen/TF in the assay, no thrombin is generated during 15-min microfluidic perfusion. At low CTI (no TF), the generation of FXIa leads to fibrin polymerization at ~300 s after the initiation of flow over collagen, an onset time shortened at zero CTI and prolonged at high CTI. The engagement of FXIa was difficult to observe for clotting on high TF surfaces due to the dominance of the extrinsic pathway. Low TF surfaces allowed observable crosstalk between extrinsic pathway generation of thrombin and thrombin-mediated activation of FXIa, a feedback detected at >5 min and attenuated with polyphosphate inhibitor. From thrombin-antithrombin immunoassay of the effluent of blood flowing over collagen/TF, the majority of thrombin was found captured on intrathrombus fibrin. Additionally, extreme shear rates (>10,000 s−1) can generate massive von Willebrand Factor fibers that capture FXIIa and FXIa to drive fibrin generation, an event that facilitates VWF fiber dissolution under fibrinolytic conditions. Finally, we found that occlusive sterile thrombi subjected to pressure drops >70 mm-Hg/mm-clots have interstitial stresses sufficient to drive NETosis. These microfluidic studies highlight the interaction of contact pathway factors with the extrinsic pathway, platelet polyphosphate, VWF fibers, and potentially shear-induced NETs.
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Affiliation(s)
- Shu Zhu
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Bradley A Herbig
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Xinren Yu
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Jason Chen
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, United States
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Zhu S, Chen J, Diamond SL. Establishing the Transient Mass Balance of Thrombosis: From Tissue Factor to Thrombin to Fibrin Under Venous Flow. Arterioscler Thromb Vasc Biol 2018; 38:1528-1536. [PMID: 29724819 PMCID: PMC6023760 DOI: 10.1161/atvbaha.118.310906] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 04/19/2018] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Objective— We investigated the coregulation of thrombin and fibrin as blood flows over a procoagulant surface. Approach and Results— Using microfluidic perfusion of factor XIIa-inhibited human whole blood (200 s−1 wall shear rate) over a 250-μm long patch of collagen/TF (tissue factor; ≈1 molecule per μm2) and immunoassays of the effluent for F1.2 (prothrombin fragment 1.2), TAT (thrombin–antithrombin complex), and D-dimer (post–end point plasmin digest), we sought to establish the transient mass balance for clotting under venous flow. F1.2 (but almost no free thrombin detected via TAT assay) continually eluted from clots when fibrin was allowed to form. Low-dose fluorescein-Phe-Pro-Arg-chloromethylketone stained fibrin-bound thrombin—a staining ablated by anti–γ′-fibrinogen or the fibrin inhibitor glypro-arg-pro but highly resistant to 7-minute buffer rinse, demonstrating tight binding of thrombin to γ′-fibrin. With fibrin polymerizing for 500 seconds, 92 000 thrombin molecules and 203 000 clot-associated fibrin monomer equivalents were generated per TF molecule (or per μm2). Fibrin reached 15 mg/mL in the pore space (porosity ≈0.5) of a 15-μm-thick thrombus core by 500 seconds and 30 mg/mL by 800 seconds. For a known rate of ≈60 FPA (fibrinopeptide-A) per thrombin per second, each thrombin molecule generated only 3 fibrin monomer equivalents during 500 seconds, indicating an intraclot thrombin half-life of ≈70 ms, much shorter than its diffusional escape time (≈10 seconds). By 800 seconds, gly-pro-arg-pro allowed 4-fold more F1.2 generation, consistent with gly-pro-arg-pro ablating fibrin’s antithrombin-I activity and facilitating thrombin-mediated FXIa activation. Conclusions— Under flow, fibrinogen continually penetrates the clot, and γ′-fibrin regulates thrombin.
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Affiliation(s)
- Shu Zhu
- From the Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia
| | - Jason Chen
- From the Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia
| | - Scott L Diamond
- From the Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia.
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27
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Pujos JS, Reyssat M, Le Goff A. Experimental and numerical study of platelets rolling on a von Willebrand factor-coated surface. Med Eng Phys 2018; 55:25-33. [PMID: 29599066 DOI: 10.1016/j.medengphy.2018.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/26/2018] [Accepted: 03/13/2018] [Indexed: 11/26/2022]
Abstract
Blood platelets circulate in the blood and adhere to wounded vessels to initiate coagulation and healing. The first step of this process is the capture of flowing platelets by adhesive molecules located at the wounded vessel wall. In this article, we study the transport of fixed blood platelets in a microfluidic channel coated with von Willebrand factor (vWF), a large multimeric protein expressed by endothelial cells in the vicinity of wounds. We measure the number of platelets adsorbed at the channel surface as a function of both time and space. Experimental results are compared with a new transport model. We show that transverse diffusion is an important feature of our model, while the rolling behaviour of the bounded platelets can be neglected.
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Affiliation(s)
- Justine S Pujos
- ESPCI Paris, PSL Research University, CNRS UMR 7083 Gulliver, 10 rue Vauquelin, 75231 Paris Cedex 05, France
| | - Mathilde Reyssat
- ESPCI Paris, PSL Research University, CNRS UMR 7083 Gulliver, 10 rue Vauquelin, 75231 Paris Cedex 05, France
| | - Anne Le Goff
- ESPCI Paris, PSL Research University, CNRS UMR 7083 Gulliver, 10 rue Vauquelin, 75231 Paris Cedex 05, France; Sorbonne Universités, Université de Technologie de Compiègne, CNRS UMR 7338 Biomécanique et Bioingénierie, Centre de recherche Royallieu, CS 60 319, Compiègne cedex 60 203, France.
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28
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Brouns SLN, van Geffen JP, Heemskerk JWM. High-throughput measurement of human platelet aggregation under flow: application in hemostasis and beyond. Platelets 2018. [DOI: 10.1080/09537104.2018.1447660] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Sanne L. N. Brouns
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Johanna P. van Geffen
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Johan W. M. Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
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Yu X, Tan J, Diamond SL. Hemodynamic force triggers rapid NETosis within sterile thrombotic occlusions. J Thromb Haemost 2018; 16:316-329. [PMID: 29156107 PMCID: PMC5809303 DOI: 10.1111/jth.13907] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Indexed: 01/19/2023]
Abstract
Essentials Neutrophil extracellular traps (NETs) are generated during thrombosis and sepsis. The effect of hemodynamics on NETosis during sterile thrombosis was studied using microfluidics. Pressure gradients > 70 mmHg per mm-clot across sterile occlusions drive shear-induced NETosis. High interstitial hemodynamic forces trigger rapid NET release. SUMMARY Background Neutrophil extracellular traps (NETs) are released when neutrophils encounter infectious pathogens, especially during sepsis. Additionally, NETosis occurs during venous and arterial thrombosis, disseminated intravascular coagulation, and trauma. Objective To determine whether hemodynamic forces trigger NETosis during sterile thrombosis. Methods NETs were imaged with Sytox Green during microfluidic perfusion of activated factor XII-inhibited or thrombin-inhibited human whole blood over fibrillar collagen (with or without tissue factor). Results For perfusions at initial inlet venous or arterial wall shear rates (100 s-1 or 1000 s-1 ), platelets rapidly accumulated and occluded microchannels with subsequent neutrophil infiltration under either flow condition; however, NETosis was detected only in the arterial condition. The level of shear-induced NETs (SINs) at 30 min was > 150-fold higher in the arterial condition in the absence of thrombin and > 80-fold greater in the presence of thrombin than the level in the venous condition. With or without thrombin, venous perfusion for 15 min generated no NETs, but an abrupt shift-up to arterial perfusion triggered NETosis within 2 min, NETs eventually reaching levels 15 min later that were 60-fold greater than that in microchannels without perfusion shift-up. SINs contained citrullinated histone H3 and myeloperoxidase, and were DNase-sensitive, but were not blocked by inhibitors of platelet-neutrophil adhesion, high-mobility group protein box 1-receptor for advanced glycation end products interaction, cyclooxygenase, ATP/ADP, or peptidylarginine deiminase 4. For measured pressure gradients exceeding 70 mmHg per millimeter of clot across NET-generating occlusions to drive interstitial flow, the calculated fluid shear stress on neutrophils exceeded the known lytic value of 150 dyne cm-2 . Conclusions High interstitial hemodynamic forces can drive physically entrapped neutrophils to rapidly release NETs during sterile occlusive thrombosis.
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Affiliation(s)
- X. Yu
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | - J. Tan
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | - S. L. Diamond
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104
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Valerio L, Sheriff J, Tran PL, Brengle W, Redaelli A, Fiore GB, Pappalardo F, Bluestein D, Slepian MJ. Routine clinical anti-platelet agents have limited efficacy in modulating hypershear-mediated platelet activation associated with mechanical circulatory support. Thromb Res 2017; 163:162-171. [PMID: 29428715 DOI: 10.1016/j.thromres.2017.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/03/2017] [Accepted: 12/02/2017] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Continuous flow ventricular assist devices (cfVADs) continue to be limited by thrombotic complications associated with disruptive flow patterns and supraphysiologic shear stresses. Patients are prescribed complex antiplatelet therapies, which do not fully prevent recurrent thromboembolic events. This is partially due to limited data on antiplatelet efficacy under cfVAD-associated shear conditions. MATERIALS AND METHODS We investigated the efficacy of antiplatelet drugs directly acting on three pathways: (1) cyclooxygenase (aspirin), (2) phosphodiesterase (dipyridamole, pentoxifylline, cilostazol), and (3) glycoprotein IIb-IIIa (eptifibatide). Gel-filtered platelets treated with these drugs were exposed for 10min to either constant shear stresses (30dyne/cm2 and 70dyne/cm2) or dynamic shear stress profiles extracted from simulated platelet trajectories through a cfVAD (Micromed DeBakey). Platelet activation state (PAS) was measured using a modified prothrombinase-based assay, with drug efficacy quantified based on PAS reduction compared to untreated controls. RESULTS AND CONCLUSIONS Significant PAS reduction was observed for all drugs after exposure to 30dyne/cm2 constant shear stress, and all drugs but dipyridamole after exposure to the 30th percentile shear stress waveform of the cfVAD. However, only cilostazol was significantly effective after 70dyne/cm2 constant shear stress exposure, though no significant reduction was observed upon exposure to median shear stress conditions in the cfVAD. These results, coupled with the persistence of reported clinical thrombotic complication, suggest the need for the development of new classes of drugs that are especially designed to mitigate thrombosis in cfVAD patients, while reducing or eliminating the risk of bleeding.
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Affiliation(s)
- Lorenzo Valerio
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy; Department of Cardiothoracic Anesthesia and Intensive Care, Istituto Scientifico San Raffaele, Milan, Italy
| | - Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Phat L Tran
- Department of Biomedical Engineering, Sarver Heart Center, University of Arizona, Tucson, AZ, USA
| | - William Brengle
- Department of Biomedical Engineering, Sarver Heart Center, University of Arizona, Tucson, AZ, USA
| | - Alberto Redaelli
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Gianfranco B Fiore
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Federico Pappalardo
- Department of Cardiothoracic Anesthesia and Intensive Care, Istituto Scientifico San Raffaele, Milan, Italy
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Marvin J Slepian
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA; Department of Biomedical Engineering, Sarver Heart Center, University of Arizona, Tucson, AZ, USA; Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, AZ, USA.
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31
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Lee MY, Verni CC, Herbig BA, Diamond SL. Soluble fibrin causes an acquired platelet glycoprotein VI signaling defect: implications for coagulopathy. J Thromb Haemost 2017; 15:2396-2407. [PMID: 28981200 PMCID: PMC5716900 DOI: 10.1111/jth.13863] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Indexed: 11/27/2022]
Abstract
Essentials Collagen and thrombin when used simultaneously generate highly activated platelets. The effect of thrombin stimulation on subsequent glycoprotein VI (GPVI) function was observed. Soluble fibrin, but not protease activated receptor (PAR) activation, prevented GPVI activation. Circulating soluble fibrin in coagulopathic blood may cause an acquired GPVI signaling defect. SUMMARY Background In coagulopathic blood, circulating thrombin may drive platelet dysfunction. Methods/Results Using calcium dye-loaded platelets, the effect of thrombin exposure and soluble fibrin generation on subsequent platelet GPVI function was investigated. Exposure of apixaban-treated platelet-rich plasma (12% PRP) to thrombin (1-10 nm), but not ADP or thromboxane mimetic U46619 exposure, dramatically blocked subsequent GPVI activation by convulxin, collagen-related peptide or fibrillar collagen. Consistent with soluble fibrin multimerizing and binding GPVI, the onset of convulxin insensitivity required 200-500 s of thrombin exposure, was not mimicked by exposure to PAR-1/4 activating peptides, was not observed with washed platelets, and was blocked by fibrin polymerization inhibitor (GPRP) or factor XIIIa inhibitor (T101). PAR-1 signaling through Gαq was not required because vorapaxar blocked thrombin-induced calcium mobilization but had no effect on the ability of thrombin to impair GPVI-signaling. Convulxin insensitivity was unaffected by the metalloprotease inhibitor GM6001 or the αIIb β3 antagonist GR144053, indicating negligible roles for GPVI shedding or αIIb β3 binding of fibrin. Thrombin treatment of washed platelets resuspended in purified fibrinogen also produced convulxin insensitivity that was prevented by GPRP. Exposure of apixaban/PPACK-treated whole blood to thrombin-treated fibrinogen resulted in > 50% decrease in platelet deposition in a collagen microfluidic assay that required soluble fibrin assembly. Conclusions Conversion of only 1% plasma fibrinogen in coagulopathic blood would generate 90 nm soluble fibrin, far exceeding ~1 nmGPVI in blood. Soluble fibrin, rather than thrombin-induced platelet activation throuh PAR-1 and PAR-4, downregulated GPVI-signaling in response to stimuli, and may lead to subsequent hypofunction of endogenous or transfused platelets.
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Affiliation(s)
- Mei Yan Lee
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christopher C. Verni
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bradley A. Herbig
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Scott L. Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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32
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Lindahl T, Faxälv L, Claesson K. Counting the platelets: a robust and sensitive quantification method for thrombus formation. Thromb Haemost 2017; 115:1178-90. [DOI: 10.1160/th15-10-0799] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/25/2016] [Indexed: 11/05/2022]
Abstract
SummaryFlow chambers are common tools used for studying thrombus formation in vitro. However, the use of such devices is not standardised and there is a large diversity among the flow chamber systems currently used, and also in the methods used for quantifying the thrombus development. It was the study objective to evaluate a new method for analysis and quantification of platelet thrombus formation that can facilitate comparison of results between research groups. Whole blood was drawn over a collagen patch in commercial Ibid or in-house constructed PDMS flow chambers. Five percent of the platelets were fluorescently labelled and z-stack time-lapse images were captured during thrombus formation. Images were processed in a Python script in which the number of platelets and their respective x-, yand z-positions were obtained. For comparison with existing methods the platelets were also labelled and quantified using fluorescence intensity and thrombus volume estimations by confocal microscopy. The presented method was found less sensitive to microscope and image adjustments and provides more details on thrombus development dynamics than the methods for measuring fluorescence intensity and thrombus volume estimation. The platelet count method produced comparable results with commercial and PDMS flow chambers, and could also obtain information regarding the stability of each detected platelet in the thrombus. In conclusion, quantification of thrombus formation by platelet count is a sensitive and robust method that enables measurement of platelet accumulation and platelet stability in an absolute scale that could be used for comparisons between research groups.
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33
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Li R, Panckeri KA, Fogarty PF, Cuker A, Diamond SL. Recombinant factor VIIa addition to haemophilic blood perfused over collagen/tissue factor can sufficiently bypass the factor IXa/VIIIa defect to rescue fibrin generation. Haemophilia 2017; 23:759-768. [PMID: 28475272 PMCID: PMC5623167 DOI: 10.1111/hae.13259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2017] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Factor VIII (FVIII) or factor IX (FIX)-deficient haemophilic patients display deficits in platelet and fibrin deposition under flow detectable in microfluidics. Compared to fibrin generation, decreased platelet deposition in haemophilic blood flow is more easily rescued with recombinant factor VIIa (rFVIIa), whereas rFVIIa requires FXIIa participation to generate fibrin when tissue factor (TF) is absent. AIMS Perfusion of haemophilic whole blood (WB) over collagen/TF surfaces was used to determine whether rFVIIa/TF was sufficient to bypass poor FIXa/FVIIIa function in blood from patients with haemophilia A and B. METHODS Whole blood treated with high-dose corn trypsin inhibitor (40 μg mL-1 ) from seven healthy donors and 10 patients was perfused over fibrillar collagen presenting low or high TF (TFlow or TFhigh ) at wall shear rate of 100 s-1 . RESULTS With WB from healthy controls, platelet deposition and fibrin accumulation increased as TF increased. Factor-deficient WB (1-3% of normal) displayed striking deficits in platelet deposition and fibrin formation at either TFlow or TFhigh . In contrast, mildly factor-deficient WB (14-32%) supported fibrin formation under flow on TFhigh /collagen. With either TFlow or TFhigh , exogenously added rFVIIa (20 nm) increased platelet deposition and fibrin accumulation in WB from factor-deficient patients (1-3% of normal) to levels commensurate with untreated healthy WB. CONCLUSION The absence of FIXa/FVIIIa in patients with severe haemophilia results in deficits in fibrin formation that cannot be rescued by wall-derived TF ex vivo. The effects of rFVIIa on platelet adhesion and rFVIIa/TF can act together to reinforce thrombin generation, platelet deposition and fibrin formation under flow.
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Affiliation(s)
- Ruizhi Li
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA. USA
| | - Karen A. Panckeri
- Comprehensive Hemophilia and Thrombosis Program, Hospital of the University of Pennsylvania, Philadelphia, PA. USA
| | - Patrick F. Fogarty
- Comprehensive Hemophilia and Thrombosis Program, Hospital of the University of Pennsylvania, Philadelphia, PA. USA
| | - Adam Cuker
- Comprehensive Hemophilia and Thrombosis Program, Hospital of the University of Pennsylvania, Philadelphia, PA. USA
| | - Scott L. Diamond
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA. USA
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Govindarajan V, Rakesh V, Reifman J, Mitrophanov AY. Computational Study of Thrombus Formation and Clotting Factor Effects under Venous Flow Conditions. Biophys J 2017; 110:1869-1885. [PMID: 27119646 PMCID: PMC4850327 DOI: 10.1016/j.bpj.2016.03.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/03/2016] [Accepted: 03/08/2016] [Indexed: 11/24/2022] Open
Abstract
A comprehensive understanding of thrombus formation as a physicochemical process that has evolved to protect the integrity of the human vasculature is critical to our ability to predict and control pathological states caused by a malfunctioning blood coagulation system. Despite numerous investigations, the spatial and temporal details of thrombus growth as a multicomponent process are not fully understood. Here, we used computational modeling to investigate the temporal changes in the spatial distributions of the key enzymatic (i.e., thrombin) and structural (i.e., platelets and fibrin) components within a growing thrombus. Moreover, we investigated the interplay between clot structure and its mechanical properties, such as hydraulic resistance to flow. Our model relied on the coupling of computational fluid dynamics and biochemical kinetics, and was validated using flow-chamber data from a previous experimental study. The model allowed us to identify the distinct patterns characterizing the spatial distributions of thrombin, platelets, and fibrin accumulating within a thrombus. Our modeling results suggested that under the simulated conditions, thrombin kinetics was determined predominantly by prothrombinase. Furthermore, our simulations showed that thrombus resistance imparted by fibrin was ∼30-fold higher than that imparted by platelets. Yet, thrombus-mediated bloodflow occlusion was driven primarily by the platelet deposition process, because the height of the platelet accumulation domain was approximately twice that of the fibrin accumulation domain. Fibrinogen supplementation in normal blood resulted in a nonlinear increase in thrombus resistance, and for a supplemented fibrinogen level of 48%, the thrombus resistance increased by ∼2.7-fold. Finally, our model predicted that restoring the normal levels of clotting factors II, IX, and X while simultaneously restoring fibrinogen (to 88% of its normal level) in diluted blood can restore fibrin generation to ∼78% of its normal level and hence improve clot formation under dilution.
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Affiliation(s)
- Vijay Govindarajan
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland
| | - Vineet Rakesh
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland.
| | - Alexander Y Mitrophanov
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland
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35
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Abstract
Platelets contribute to thrombus formation in a variety of ways. Platelet adhesion, activation, and thrombus growth depend greatly on the type of hemodynamic environment surrounding an inciting event. Microfluidic systems may be used to explore these relationships. In this review, we describe some important considerations required in the design of a microfluidic system and identify some limitations that may require use of a macroscale system.
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Affiliation(s)
- Susan M Hastings
- a GWW School of Mechanical Engineering, Institute for Bioengineering and Biosciences , Georgia Institute of Technology , Atlanta , GA , USA
| | - Michael T Griffin
- a GWW School of Mechanical Engineering, Institute for Bioengineering and Biosciences , Georgia Institute of Technology , Atlanta , GA , USA
| | - David N Ku
- a GWW School of Mechanical Engineering, Institute for Bioengineering and Biosciences , Georgia Institute of Technology , Atlanta , GA , USA
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36
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Pugh N, Maddox BD, Bihan D, Taylor KA, Mahaut-Smith MP, Farndale RW. Differential integrin activity mediated by platelet collagen receptor engagement under flow conditions. Thromb Haemost 2017; 117:1588-1600. [PMID: 28536721 PMCID: PMC6291897 DOI: 10.1160/th16-12-0906] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 04/22/2017] [Indexed: 11/15/2022]
Abstract
The platelet receptors glycoprotein (Gp)VI, integrin α
2
β
1
and GpIb/V/IX mediate platelet adhesion and activation during thrombogenesis. Increases of intracellular Ca
2+
([Ca
2+
]
i
) are key signals during platelet activation; however, their relative importance in coupling different collagen receptors to functional responses under shear conditions remains unclear. To study shear-dependent, receptor-specific platelet responses, we used collagen or combinations of receptor-specific collagen-mimetic peptides as substrates for platelet adhesion and activation in whole human blood under arterial flow conditions and compared real-time and endpoint parameters of thrombus formation alongside [Ca
2+
]
i
measurements using confocal imaging. All three collagen receptors coupled to [Ca
2+
]
i
signals, but these varied in amplitude and temporal pattern alongside variable integrin activation. GpVI engagement produced large, sustained [Ca
2+
]
i
signals leading to realtime increases in integrins α
2
β
1
− and α
IIb
β
3
-mediated platelet adhesion. α
IIb
β
3
-dependent platelet aggregation was dependent on P
2
Y
12
signalling. Co-engagement of α
2
β
1
and GpIb/V/IX generated transient [Ca
2+
]
i
spikes and low amplitude [Ca
2+
]
i
responses that potentiated GpVI-dependent [Ca
2+
]
i
signalling. Therefore α
2
β
1
GpIb/V/IX and GpVI synergise to generate [Ca
2+
]
i
signals that regulate platelet behaviour and thrombus formation. Antagonism of secondary signalling pathways reveals distinct, separate roles for α
IIb
β
3
in stable platelet adhesion and aggregation.
Supplementary Material to this article is available online at
www.thrombosis-online.com
.
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Affiliation(s)
- Nicholas Pugh
- Nicholas Pugh, Department of Biomedical and Forensic Sciences, Anglia Ruskin University, Cambridge, CB1 1PT, UK, Tel.: +44 8451962661, E-mail:
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Abstract
The systems analysis of thrombosis seeks to quantitatively predict blood function in a given vascular wall and hemodynamic context. Relevant to both venous and arterial thrombosis, a Blood Systems Biology approach should provide metrics for rate and molecular mechanisms of clot growth, thrombotic risk, pharmacological response, and utility of new therapeutic targets. As a rapidly created multicellular aggregate with a polymerized fibrin matrix, blood clots result from hundreds of unique reactions within and around platelets propagating in space and time under hemodynamic conditions. Coronary artery thrombosis is dominated by atherosclerotic plaque rupture, complex pulsatile flows through stenotic regions producing high wall shear stresses, and plaque-derived tissue factor driving thrombin production. In contrast, venous thrombosis is dominated by stasis or depressed flows, endothelial inflammation, white blood cell-derived tissue factor, and ample red blood cell incorporation. By imaging vessels, patient-specific assessment using computational fluid dynamics provides an estimate of local hemodynamics and fractional flow reserve. High-dimensional ex vivo phenotyping of platelet and coagulation can now power multiscale computer simulations at the subcellular to cellular to whole vessel scale of heart attacks or strokes. In addition, an integrated systems biology approach can rank safety and efficacy metrics of various pharmacological interventions or clinical trial designs.
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Affiliation(s)
- Scott L Diamond
- From the Department of Chemical Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia.
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38
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Li R, Grosser T, Diamond SL. Microfluidic whole blood testing of platelet response to pharmacological agents. Platelets 2017; 28:457-462. [PMID: 28102731 DOI: 10.1080/09537104.2016.1268254] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Platelets present a number of intracellular and transmembrane targets subject to pharmacological modulation, either for cardiovascular disease reduction or as an unintended drug response. Microfluidic devices allow human blood to clot on a defined surface under controlled hemodynamic and pharmacological conditions. The potencies of a number of antiplatelet and anticancer drugs have been tested with respect to platelet deposition on collagen under flow. Inhibitors of cyclooxygenase-1 (COX-1) reduce platelet deposition, either when added ex vivo to blood or ingested orally by patients prior to testing. Some individuals display a functional "aspirin-insensitivity" in microfluidic assay. When certain nonsteroidal anti-inflammatory drugs (NSAIDs) are taken orally, they block COX-1 acetylation by aspirin with concomitant reduction of aspirin efficacy against platelets in microfluidic assay. Both P2Y1 and P2Y12 inhibitors reduce platelet deposition under flow, as do NO donors and iloprost that target the guanylate cyclase and the prostacyclin receptor, respectively. In a microfluidic assay of 37 kinase inhibitors, dasatinib had potent antiplatelet activity, while bosutinib was less potent. Dasatinib and bosutinib have known profiles against numerous kinases, revealing overlapping and nonoverlapping activities relevant to their unique actions against platelets. Also, dasatinib caused a marked and specific inhibition of GPVI signaling induced by convulxin, consistent with a dasatinib-associated bleeding risk. Microfluidic devices facilitate drug library screening, dose-response testing, and drug-drug interaction studies. Kinase inhibitors developed as anticancer agents may present antiplatelet activities that are detectable by microfluidic assay and potentially linked to bleeding risks.
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Affiliation(s)
- Ruizhi Li
- a Institute for Medicine and Engineering, University of Pennsylvania , Philadelphia , PA , USA
| | - Tilo Grosser
- b Institute for Translational Medicine and Therapeutics, University of Pennsylvania , Philadelphia , PA , USA
| | - Scott L Diamond
- a Institute for Medicine and Engineering, University of Pennsylvania , Philadelphia , PA , USA.,b Institute for Translational Medicine and Therapeutics, University of Pennsylvania , Philadelphia , PA , USA
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Soaita I, Yin W, Rubenstein DA. Glycated albumin modifies platelet adhesion and aggregation responses. Platelets 2017; 28:682-690. [PMID: 28067098 DOI: 10.1080/09537104.2016.1260703] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A diabetic vasculature is detrimental to cardiovascular health through the actions of advanced glycation end products (AGEs) on endothelial cells and platelets. Platelets activated by AGEs agonize endothelial responses promoting cardiovascular disease (CVD) development. While it has been established that AGEs can alter platelet functions, little is known about the specific platelet pathways that AGEs modify. Therefore, we evaluated the effects of AGEs on specific salient platelet pathways related to CVDs and whether the effects that AGEs elicit are dependent on glycation extent. To accomplish our objective, platelets were incubated with reversibly or irreversibly glycated albumin. A time course for adhesion and aggregation agonist receptor expression was assessed. Optical platelet aggregometry was used to confirm the functional activity of platelets after AGE exposure. In general, platelets subjected to glycated albumin had a significantly enhanced adhesion and aggregation potential. Furthermore, we observed an enhancement in dense body secretion and intracellular calcium concentration. This was especially prevalent for platelets exposed to irreversibly glycated albumin. Additionally, functional aggregation correlated well with receptor expression, suggesting that AGE-induced altered receptor sensitivity translated to altered platelet functions. Our findings indicate that under diabetic vascular conditions platelets become more susceptible to activation and aggregation due to an overall enhanced receptor expression, which may act to promote CVD development.
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Affiliation(s)
- Ioana Soaita
- a Department of Biomedical Engineering , Stony Brook University , Stony Brook , NY , USA
| | - Wei Yin
- a Department of Biomedical Engineering , Stony Brook University , Stony Brook , NY , USA
| | - David A Rubenstein
- a Department of Biomedical Engineering , Stony Brook University , Stony Brook , NY , USA
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Zhu S, Herbig BA, Li R, Colace TV, Muthard RW, Neeves KB, Diamond SL. In microfluidico: Recreating in vivo hemodynamics using miniaturized devices. Biorheology 2016; 52:303-18. [PMID: 26600269 DOI: 10.3233/bir-15065] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Microfluidic devices create precisely controlled reactive blood flows and typically involve: (i) validated anticoagulation/pharmacology protocols, (ii) defined reactive surfaces, (iii) defined flow-transport regimes, and (iv) optical imaging. An 8-channel device can be run at constant flow rate or constant pressure drop for blood perfusion over a patterned collagen, collagen/kaolin, or collagen/tissue factor (TF) to measure platelet, thrombin, and fibrin dynamics during clot growth. A membrane-flow device delivers a constant flux of platelet agonists or coagulation enzymes into flowing blood. A trifurcated device sheaths a central blood flow on both sides with buffer, an ideal approach for on-chip recalcification of citrated blood or drug delivery. A side-view device allows clotting on a porous collagen/TF plug at constant pressure differential across the developing clot. The core-shell architecture of clots made in mouse models can be replicated in this device using human blood. For pathological flows, a stenosis device achieves shear rates of >100,000 s(-1) to drive plasma von Willebrand factor (VWF) to form thick long fibers on collagen. Similarly, a micropost-impingement device creates extreme elongational and shear flows for VWF fiber formation without collagen. Overall, microfluidics are ideal for studies of clotting, bleeding, fibrin polymerization/fibrinolysis, cell/clot mechanics, adhesion, mechanobiology, and reaction-transport dynamics.
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Affiliation(s)
- Shu Zhu
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Bradley A Herbig
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Ruizhi Li
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas V Colace
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Ryan W Muthard
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Keith B Neeves
- Department of Chemical and Biomolecular Engineering, Colorado School of Mines, Golden, CO, USA
| | - Scott L Diamond
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
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Zhu S, Lu Y, Sinno T, Diamond SL. Dynamics of Thrombin Generation and Flux from Clots during Whole Human Blood Flow over Collagen/Tissue Factor Surfaces. J Biol Chem 2016; 291:23027-23035. [PMID: 27605669 DOI: 10.1074/jbc.m116.754671] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Indexed: 12/20/2022] Open
Abstract
Coagulation kinetics are well established for purified blood proteases or human plasma clotting isotropically. However, less is known about thrombin generation kinetics and transport within blood clots formed under hemodynamic flow. Using microfluidic perfusion (wall shear rate, 200 s-1) of corn trypsin inhibitor-treated whole blood over a 250-μm long patch of type I fibrillar collagen/lipidated tissue factor (TF; ∼1 TF molecule/μm2), we measured thrombin released from clots using thrombin-antithrombin immunoassay. The majority (>85%) of generated thrombin was captured by intrathrombus fibrin as thrombin-antithrombin was largely undetectable in the effluent unless Gly-Pro-Arg-Pro (GPRP) was added to block fibrin polymerization. With GPRP present, the flux of thrombin increased to ∼0.5 × 10-12 nmol/μm2-s over the first 500 s of perfusion and then further increased by ∼2-3-fold over the next 300 s. The increased thrombin flux after 500 s was blocked by anti-FXIa antibody (O1A6), consistent with thrombin-feedback activation of FXI. Over the first 500 s, ∼92,000 molecules of thrombin were generated per surface TF molecule for the 250-μm-long coating. A single layer of platelets (obtained with αIIbβ3 antagonism preventing continued platelet deposition) was largely sufficient for thrombin production. Also, the overall thrombin-generating potential of a 1000-μm-long coating became less efficient on a per μm2 basis, likely due to distal boundary layer depletion of platelets. Overall, thrombin is robustly generated within clots by the extrinsic pathway followed by late-stage FXIa contributions, with fibrin localizing thrombin via its antithrombin-I activity as a potentially self-limiting hemostatic mechanism.
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Affiliation(s)
- Shu Zhu
- From the Department of Chemical and Biomolecular Engineering, Institute of Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Yichen Lu
- From the Department of Chemical and Biomolecular Engineering, Institute of Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Talid Sinno
- From the Department of Chemical and Biomolecular Engineering, Institute of Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Scott L Diamond
- From the Department of Chemical and Biomolecular Engineering, Institute of Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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Zhu S, Tomaiuolo M, Diamond SL. Minimum wound size for clotting: flowing blood coagulates on a single collagen fiber presenting tissue factor and von Willebrand factor. Integr Biol (Camb) 2016; 8:813-20. [PMID: 27339024 PMCID: PMC4980166 DOI: 10.1039/c6ib00077k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
It is unknown if a lower size limit exists for human blood coagulation under flow over physiological vessel wall triggers as small as a single collagen fiber. Prior determinations of the smallest sized surface stimuli necessary for clotting of human blood, defined as the patch size threshold, have not deployed whole blood, hemodynamic flow, and platelet adhesive stimuli. For whole blood perfused in microfluidic devices, we report that steady venous flow (wall shear rate, 100 s(-1)) was sufficient to drive platelet deposition on 20 micron long zones of collagen fibers or on a single fiber. With tissue factor (TF)-coated collagen, flowing blood generated robust platelet deposits, platelet-localized thrombin, and fibrin on a single collagen fiber, thus demonstrating the absence of a physiological patch size threshold under venous flow. In contrast, at arterial wall shear rate (1000 s(-1)) with TF present, essentially no platelet or fibrin deposition occurred on 20 micron collagen zones or on a single collagen fiber, demonstrating a patch threshold, which was overcome by pre-coating the collagen with von Willebrand factor (vWF). For venous flows, human blood can clot on one of the smallest biological units of a single collagen fiber presenting TF. For arterial flows, vWF together with TF allows human blood to generate thrombin and fibrin on a patch stimulus as limited as a single collagen fiber. vWF-dependent platelet adhesion represents a particle-based sensing mechanism of micron-scale stimuli that then allows amplification of the molecular components of TF-driven thrombin and fibrin production under arterial flow.
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Affiliation(s)
- Shu Zhu
- Institute for Medicine and Engineering, University of Pennsylvania, 1024 Vagelos Research Laboratories, Philadelphia, PA 19104, USA.
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Ex vivo recapitulation of trauma-induced coagulopathy and preliminary assessment of trauma patient platelet function under flow using microfluidic technology. J Trauma Acute Care Surg 2016; 80:440-9. [PMID: 27082706 DOI: 10.1097/ta.0000000000000915] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Relevant to trauma-induced coagulopathy diagnostics, microfluidic assays allow controlled hemodynamics for testing of platelet and coagulation function using whole blood. METHODS Hemodilution or hyperfibrinolysis was studied under flow with modified healthy whole blood. Furthermore, platelet function was also measured using whole blood from trauma patients admitted to a Level I trauma center. Platelet deposition was measured with PPACK-inhibited blood perfused over collagen surfaces at a wall shear rate of 200 s, whereas platelet/fibrin deposition was measured with corn trypsin inhibitor-treated blood perfused over tissue factor (TF)/collagen. RESULTS In hemodilution studies, PPACK-treated blood displayed almost no platelet deposition when diluted to 10% hematocrit with saline, platelet-poor plasma, or platelet-rich plasma. Using similar dilutions, platelet/fibrin deposition was essentially absent for corn trypsin inhibitor-treated blood perfused over TF/collagen. To mimic hyperfibrinolysis during trauma, exogenous tissue plasminogen activator (50 nM) was added to blood before perfusion over TF/collagen. At both venous and arterial flows, the generation and subsequent lysis of fibrin were detectable within 6 minutes, with lysis blocked by addition of the plasmin inhibitor, ε-aminocaproic acid. Microfluidic assay of PPACK-inhibited whole blood from trauma patients revealed striking defects in collagen response and secondary platelet aggregation in 14 of 21 patients, whereas platelet hyperfunction was detected in three of 20 patients. CONCLUSION Rapid microfluidic detection of (1) hemodilution-dependent impairment of clotting, (2) clot instability because of lysis, (3) blockade of fibrinolysis, or (4) platelet dysfunction during trauma may provide novel diagnostic opportunities to predict trauma-induced coagulopathy risk.
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Eichinger CD, Fogelson AL, Hlady V. Functional assay of antiplatelet drugs based on margination of platelets in flowing blood. Biointerphases 2016; 11:029805. [PMID: 27030476 PMCID: PMC4818277 DOI: 10.1116/1.4945305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 02/02/2023] Open
Abstract
A novel functional assay of antiplatelet drug efficacy was designed by utilizing the phenomena of platelet margination in flowing blood and transient platelet contacts with surface-immobilized platelet agonists. Flow margination enhances transient contacts of platelets with the walls of flow chambers covered with surface-immobilized proteins. Depending on the type and the surface density of the immobilized agonists, such transient interactions could "prime" the marginated platelet subpopulation for enhanced activation and adhesion downstream. By creating an upstream surface patch with an immobilized platelet agonist, platelet flow margination was used to test how effective antiplatelet drugs are in suppressing downstream platelet activation and adhesion. The platelet adhesion downstream was measured by a so-called "capture" patch region close to the distal end of the flow chamber. Platelet adhesion downstream was found to be dose-dependent on the upstream surface coverage of the "priming" patch, with immobilized fibrinogen acting as a platelet agonist. Several antiplatelet agents (acetylsalicylic acid, eptifibatide, and tirofiban) were evaluated for their efficacy in attenuating downstream adhesion after upstream platelet priming. The activation of the platelet population was found to be dependent on both the extent of the upstream agonist stimulus and the antiplatelet drug concentration. Such a relationship provides an opportunity to measure the efficacy of specific antiplatelet agents against the type and concentration of upstream platelet agonists.
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Affiliation(s)
- Colin D Eichinger
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112
| | - Aaron L Fogelson
- Department of Mathematics, University of Utah, Salt Lake City, Utah 84112
| | - Vladimir Hlady
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112
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Brass LF, Diamond SL. Transport physics and biorheology in the setting of hemostasis and thrombosis. J Thromb Haemost 2016; 14:906-17. [PMID: 26848552 PMCID: PMC4870125 DOI: 10.1111/jth.13280] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/20/2016] [Accepted: 01/26/2016] [Indexed: 02/02/2023]
Abstract
The biophysics of blood flow can dictate the function of molecules and cells in the vasculature with consequent effects on hemostasis, thrombosis, embolism, and fibrinolysis. Flow and transport dynamics are distinct for (i) hemostasis vs. thrombosis and (ii) venous vs. arterial episodes. Intraclot transport changes dramatically the moment hemostasis is achieved or the moment a thrombus becomes fully occlusive. With platelet concentrations that are 50- to 200-fold greater than platelet-rich plasma, clots formed under flow have a different composition and structure compared with blood clotted statically in a tube. The platelet-rich, core/shell architecture is a prominent feature of self-limiting hemostatic clots formed under flow. Importantly, a critical threshold concentration of surface tissue factor is required for fibrin generation under flow. Once initiated by wall-derived tissue factor, thrombin generation and its spatial propagation within a clot can be modulated by γ'-fibrinogen incorporated into fibrin, engageability of activated factor (FIXa)/activated FVIIIa tenase within the clot, platelet-derived polyphosphate, transclot permeation, and reduction of porosity via platelet retraction. Fibrin imparts tremendous strength to a thrombus to resist embolism up to wall shear stresses of 2400 dyne cm(-2) . Extreme flows, as found in severe vessel stenosis or in mechanical assist devices, can cause von Willebrand factor self-association into massive fibers along with shear-induced platelet activation. Pathological von Willebrand factor fibers are A Disintegrin And Metalloprotease with ThromboSpondin-1 domain 13 resistant but are a substrate for fibrin generation due to FXIIa capture. Recently, microfluidic technologies have enhanced the ability to interrogate blood in the context of stenotic flows, acquired von Willebrand disease, hemophilia, traumatic bleeding, and drug action.
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Affiliation(s)
- Lawrence F. Brass
- Departments of Medicine and Systems Pharmacology, University of Pennsylvania, Philadelphia, PA, USA
| | - Scott L. Diamond
- Departments of Medicine and Systems Pharmacology, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Medicine and Engineering, Department of Chemical Engineering, University of Pennsylvania, Philadelphia, PA, USA
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46
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Zhu S, Welsh JD, Brass LF, Diamond SL. Platelet-targeting thiol reduction sensor detects thiol isomerase activity on activated platelets in mouse and human blood under flow. J Thromb Haemost 2016; 14:1070-81. [PMID: 26725377 PMCID: PMC4870098 DOI: 10.1111/jth.13245] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/20/2015] [Indexed: 11/28/2022]
Abstract
UNLABELLED Essentials Protein disulfide isomerases may have an essential role in thrombus formation. A platelet-binding sensor (PDI-sAb) was developed to detect thiol reductase activity under flow. Primary human platelet adhesion to collagen at 200 s(-1) was correlated with the PDI-sAb signal. Detected thiol reductase activity was localized in the core of growing thrombi at the site of injury in mice. SUMMARY Background Protein disulfide isomerases (PDIs) may regulate thrombus formation in vivo, although the sources and targets of PDIs are not fully understood. Methods and results Using click chemistry to link anti-CD61 and a C-terminal azido disulfide-linked peptide construct with a quenched reporter, we developed a fluorogenic platelet-targeting antibody (PDI-sAb) for thiol reductase activity detection in whole blood under flow conditions. PDI-sAb was highly responsive to various exogenous reducing agents (dithiothreitol, glutathione and recombinant PDI) and detected thiol reductase activity on P-selectin/phosphatidylserine-positive platelets activated with convulxin/PAR1 agonist peptide, a signal partially blocked by PDI inhibitors and antibody. In a microfluidic thrombosis model using 4 μg mL(-1) corn trypsin inhibitor-treated human blood perfused over collagen (wall shear rate = 100 s(-1) ), the PDI-sAb signal increased mostly over the first 200 s, whereas platelets continually accumulated for over 500 s, indicating that primary adhesion to collagen, but not secondary aggregation, was correlated with the PDI-sAb signal. Rutin and the PDI blocking antibody RL90 reduced platelet adhesion and the PDI-sAb signal only when thrombin production was inhibited with PPACK, suggesting limited effects of platelet thiol isomerase activity on platelet aggregation on collagen in the presence of thrombin. With anti-mouse CD41 PDI-sAb used in an arteriolar laser injury model, thiol reductase activity was localized in the core of growing thrombi where platelets displayed P-selectin and were in close proximity to disrupted endothelium. Conclusion PDI-sAb is a sensitive and real-time reporter of platelet- and vascular-derived disulfide reduction that targets clots as they form under flow to reveal spatial gradients.
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Affiliation(s)
- S Zhu
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - J D Welsh
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - L F Brass
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - S L Diamond
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
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Microfluidic approaches for the assessment of blood cell trauma: a focus on thrombotic risk in mechanical circulatory support devices. Int J Artif Organs 2016; 39:184-93. [PMID: 27034318 DOI: 10.5301/ijao.5000485] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2016] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Mechanical circulatory support devices (MCSDs) are emerging as a valuable therapeutic option for the management of end-stage heart failure. However, although recipients are routinely administered with anti-thrombotic (AT) drugs, thrombosis persists as a severe post-implant complication. Conventional clinical assays and coagulation markers demonstrate partial ability in preventing the onset of thrombosis. Through years, different laboratory techniques have been proposed as potential tools for the evaluation of platelets' hemostatic response in MCSD recipients. Most rely on platelet aggregation tests; they are performed in static or low shear conditions, neglecting the prominent contribution of MCSD shear-induced mechanical load in enhancing platelet activation (PA). On the other hand, those tests able to account for shear-induced PA have limited possibility of effective clinical translation. AIMS AND METHODS Advances on this side have been addressed by microfluidic technology. Microfluidic devices have been developed for AT drug monitoring under flow, able to replicate physiological and/or constant shear flow conditions in vitro. In this paper, we present a newly developed microfluidic platform able to expose platelets to MCSD-specific dynamic shear stress patterns. We performed in vitro tests circulating human platelets in the microfluidic platform and quantifying the dynamics of PA by means of the Platelet Activity State (PAS) assay. RESULTS Our results prove the feasibility of using microfluidics for the diagnosis of MCSD-related thrombotic risk. This study paves the way for the development of a miniaturized point-of-care device for monitoring AT drug regimen. Such a system may have significant impact on limiting the incidence of thrombosis in MCSD recipients.
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48
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Kamat V, Muthard RW, Li R, Diamond SL. Microfluidic assessment of functional culture-derived platelets in human thrombi under flow. Exp Hematol 2015; 43:891-900.e4. [PMID: 26145051 DOI: 10.1016/j.exphem.2015.06.302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/12/2015] [Accepted: 06/25/2015] [Indexed: 11/30/2022]
Abstract
Despite their clinical significance, human platelets are not amenable to genetic manipulation, thus forcing a reliance on mouse models. Culture-derived platelets (CDPs) from human peripheral blood CD34(+) cells can be genetically altered and may eventually be used for transfusions. By use of microfluidics, the time-dependent incorporation of CD41(+)CD42(+) CDPs into clots was measured using only 54,000 CDPs doped into 27 μL of human whole blood perfused over collagen at a wall shear rate of 100 sec(-1). With the use of fluorescence-labeled human platelets (instead of CDPs) doped between 0.25% and 2% of total platelets, incorporation was highly quantitative and allowed monitoring of the anti-αIIbβ3 antagonism that occurred after collagen adhesion. CDPs were only 15% as efficient as human platelets in their incorporation into human thrombi under flow, although both cell types were equally antagonized by αIIbβ3 inhibition. Transient transfection allowed the monitoring of GFP(+) human CDP incorporation into clots. This assay quantifies genetically altered CDP function under flow.
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Affiliation(s)
- Viraj Kamat
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ryan W Muthard
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ruizhi Li
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania.
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FXIa and platelet polyphosphate as therapeutic targets during human blood clotting on collagen/tissue factor surfaces under flow. Blood 2015; 126:1494-502. [PMID: 26136249 DOI: 10.1182/blood-2015-04-641472] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/18/2015] [Indexed: 11/20/2022] Open
Abstract
Factor XIIa (FXIIa) and factor XIa (FXIa) contribute to thrombosis in animal models, whereas platelet-derived polyphosphate (polyP) may potentiate contact or thrombin-feedback pathways. The significance of these mediators in human blood under thrombotic flow conditions on tissue factor (TF) -bearing surfaces remains inadequately resolved. Human blood (corn trypsin inhibitor treated [4 μg/mL]) was tested by microfluidic assay for clotting on collagen/TF at TF surface concentration ([TF]wall) from ∼0.1 to 2 molecules per μm(2). Anti-FXI antibodies (14E11 and O1A6) or polyP-binding protein (PPXbd) were used to block FXIIa-dependent FXI activation, FXIa-dependent factor IX (FIX) activation, or platelet-derived polyP, respectively. Fibrin formation was sensitive to 14E11 at 0 to 0.1 molecules per µm(2) and sensitive to O1A6 at 0 to 0.2 molecules per µm(2). However, neither antibody reduced fibrin generation at ∼2 molecules per µm(2) when the extrinsic pathway became dominant. Interestingly, PPXbd reduced fibrin generation at low [TF]wall (0.1 molecules per µm(2)) but not at zero or high [TF]wall, suggesting a role for polyP distinct from FXIIa activation and requiring low extrinsic pathway participation. Regardless of [TF]wall, PPXbd enhanced fibrin sensitivity to tissue plasminogen activator and promoted clot retraction during fibrinolysis concomitant with an observed PPXbd-mediated reduction of fibrin fiber diameter. This is the first detection of endogenous polyP function in human blood under thrombotic flow conditions. When triggered by low [TF]wall, thrombosis may be druggable by contact pathway inhibition, although thrombolytic susceptibility may benefit from polyP antagonism regardless of [TF]wall.
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50
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Branchford BR, Ng CJ, Neeves KB, Di Paola J. Microfluidic technology as an emerging clinical tool to evaluate thrombosis and hemostasis. Thromb Res 2015; 136:13-9. [PMID: 26014643 DOI: 10.1016/j.thromres.2015.05.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 10/23/2022]
Abstract
Assessment of platelet function and coagulation under flow conditions can augment traditional static assays used to evaluate patients with suspected hemostatic or thrombotic disorders. Among the available flow-based assays, microfluidic devices require the smallest blood volume and provide multiple output options. These assays are based on the presence of wall shear stress that mimics in vivo interactions between blood components and vessel walls. Microfluidic devices can generate essential information regarding homeostatic regulation of platelet activation and subsequent engagement of the coagulation cascade leading to fibrin deposition and clot formation. Emerging data suggest that microfluidic assays may also reveal consistent patterns of hemostatic or thrombotic pathology, and could aid in assessing and monitoring patient-specific effects of coagulation-modifying therapies.
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Affiliation(s)
- Brian R Branchford
- Dept. of Pediatrics - Hematology/Oncology, University of Colorado School of Medicine, Aurora, CO, USA; University of Colorado Hemophilia and Thrombosis Center, Aurora, CO, USA
| | - Christopher J Ng
- Dept. of Pediatrics - Hematology/Oncology, University of Colorado School of Medicine, Aurora, CO, USA; University of Colorado Hemophilia and Thrombosis Center, Aurora, CO, USA
| | - Keith B Neeves
- Dept. of Chemical & Biological Engineering, Colorado School of Mines, Golden, CO, USA
| | - Jorge Di Paola
- Dept. of Pediatrics - Hematology/Oncology, University of Colorado School of Medicine, Aurora, CO, USA; University of Colorado Hemophilia and Thrombosis Center, Aurora, CO, USA; Graduate Program- Human Medical Genetics and Genomics, University of Colorado School of Medicine, Aurora, CO, USA.
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