151
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Lawrence MJ, Davies G, Nyberg M, Whitley J, Evans V, Williams R, Hellsten Y, Evans PA. The effect of tyramine infusion and exercise on blood flow, coagulation and clot microstructure in healthy individuals. Thromb Res 2018; 170:32-37. [PMID: 30098458 DOI: 10.1016/j.thromres.2018.07.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/19/2018] [Accepted: 07/24/2018] [Indexed: 11/15/2022]
Abstract
BACKGROUND The long term benefits of exercise on the cardiovascular status of a patient have been proven, however, their benefit/risk relationship with exercise intensity is unclear. Furthermore, many thromboembolic diseases such as myocardial infarction and ischaemic stroke are associated with profound catecholamine release. In this study we explore the relationship between catecholamine release and hemodynamic changes and their effect on coagulation. MATERIALS AND METHODS Twelve healthy recreationally active males were recruited. Local anesthesia was given and catheters were placed under aseptic conditions, in the femoral artery and vein of the experimental leg. The first experiment involved tyramine infusion into the femoral artery at a dose of 1.0 μmol·min-1·L leg volume-1. The second experiment involved single leg knee-extensor exercise performed at 30 W for 15 min. Venous blood was collected at each time point to assess clot microstructure using the df biomarker. RESULTS AND CONCLUSIONS Tyramine infusion causes a local noradrenaline release in the leg. The increase in noradrenaline was associated with a significant increase in clot microstructure formation (df increased from 1.692 ± 0.029 to 1.722 ± 0.047, p = 0.016). Additionally moderate intensity single leg knee extensor exercise, which minimally alters sympathetic activity, also induced an increases in df (from 1.688 ± 0.025 to 1.723 ± 0.023, p = 0.001). This suggests that exercise can alter clot microstructure formation both via an increase in catecholeamine levels and by factors related to muscle activity per se, such as increased blood flow and consequent shear. These findings have implications for recommendations of exercise in patients at risk of cardiovascular events.
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Affiliation(s)
- Matthew J Lawrence
- Haemostasis Biomedical Research Unit, Welsh Centre in Emergency Medicine Research, Morriston Hospital, ABMU Health Board, Swansea, UK; College of Medicine, Swansea University, Swansea, UK
| | - Gareth Davies
- Haemostasis Biomedical Research Unit, Welsh Centre in Emergency Medicine Research, Morriston Hospital, ABMU Health Board, Swansea, UK; College of Medicine, Swansea University, Swansea, UK
| | - Michael Nyberg
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Janet Whitley
- Haemostasis Biomedical Research Unit, Welsh Centre in Emergency Medicine Research, Morriston Hospital, ABMU Health Board, Swansea, UK; College of Medicine, Swansea University, Swansea, UK
| | - Vanessa Evans
- Haemostasis Biomedical Research Unit, Welsh Centre in Emergency Medicine Research, Morriston Hospital, ABMU Health Board, Swansea, UK; College of Medicine, Swansea University, Swansea, UK
| | - Rhodri Williams
- Haemostasis Biomedical Research Unit, Welsh Centre in Emergency Medicine Research, Morriston Hospital, ABMU Health Board, Swansea, UK; College of Engineering, Swansea University, Swansea, UK
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Phillip A Evans
- Haemostasis Biomedical Research Unit, Welsh Centre in Emergency Medicine Research, Morriston Hospital, ABMU Health Board, Swansea, UK; College of Medicine, Swansea University, Swansea, UK.
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152
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Xu S, Xu Z, Kim OV, Litvinov RI, Weisel JW, Alber M. Model predictions of deformation, embolization and permeability of partially obstructive blood clots under variable shear flow. J R Soc Interface 2018; 14:rsif.2017.0441. [PMID: 29142014 DOI: 10.1098/rsif.2017.0441] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 10/19/2017] [Indexed: 01/20/2023] Open
Abstract
Thromboembolism, one of the leading causes of morbidity and mortality worldwide, is characterized by formation of obstructive intravascular clots (thrombi) and their mechanical breakage (embolization). A novel two-dimensional multi-phase computational model is introduced that describes active interactions between the main components of the clot, including platelets and fibrin, to study the impact of various physiologically relevant blood shear flow conditions on deformation and embolization of a partially obstructive clot with variable permeability. Simulations provide new insights into mechanisms underlying clot stability and embolization that cannot be studied experimentally at this time. In particular, model simulations, calibrated using experimental intravital imaging of an established arteriolar clot, show that flow-induced changes in size, shape and internal structure of the clot are largely determined by two shear-dependent mechanisms: reversible attachment of platelets to the exterior of the clot and removal of large clot pieces. Model simulations predict that blood clots with higher permeability are more prone to embolization with enhanced disintegration under increasing shear rate. In contrast, less permeable clots are more resistant to rupture due to shear rate-dependent clot stiffening originating from enhanced platelet adhesion and aggregation. These results can be used in future to predict risk of thromboembolism based on the data about composition, permeability and deformability of a clot under specific local haemodynamic conditions.
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Affiliation(s)
- Shixin Xu
- Department of Mathematics, Division of Clinical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Zhiliang Xu
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Oleg V Kim
- Department of Mathematics, Division of Clinical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA.,Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rustem I Litvinov
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Biochemistry and Biotechnology, Kazan Federal University, Kazan 420008, Russian Federation
| | - John W Weisel
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mark Alber
- Department of Mathematics, Division of Clinical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA .,Department of Internal Medicine, Division of Clinical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA.,Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN 46556, USA.,Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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153
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Asada Y, Yamashita A, Sato Y, Hatakeyama K. Thrombus Formation and Propagation in the Onset of Cardiovascular Events. J Atheroscler Thromb 2018; 25:653-664. [PMID: 29887539 PMCID: PMC6099067 DOI: 10.5551/jat.rv17022] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ischemic cardiovascular disease is a major cause of morbidity and mortality worldwide and thrombus formation on disrupted atherosclerotic plaques is considered to trigger its onset. Although the activation of platelets and coagulation pathways has been investigated intensively, the mechanisms of thrombus formation on disrupted plaques have not been understood in detail. Platelets are thought to play a central role in the formation of arterial thrombus because of rapid flow conditions; however, thrombus that develops on disrupted plaques consistently includes large amounts of fibrin in addition to aggregated platelets. While, thrombus does not always become large enough to completely occlude the vascular lumen, indicating that the propagation of thrombus is also critical for the onset of cardiovascular events. Various factors, such as vascular wall thrombogenicity, altered blood flow and imbalanced blood hemostasis, modulate thrombus formation and propagation on disrupted plaques. Pathological findings derived from humans and experimental animal models of atherothrombosis have identified important factors that affect thrombus formation and propagation, namely platelets, extrinsic and intrinsic coagulation factors, proinflammatory factors, plaque hypoxia and blood flow alteration. These findings might provide insight into the mechanisms of thrombus formation and propagation on disrupted plaques that lead to the onset of cardiovascular events.
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Affiliation(s)
- Yujiro Asada
- Department of Pathology, Faculty of Medicine, University of Miyazaki
| | - Atsushi Yamashita
- Department of Pathology, Faculty of Medicine, University of Miyazaki
| | - Yuichiro Sato
- Department of Diagnostic Pathology, University of Miyazaki Hospital, University of Miyazaki
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154
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Wain RAJ, Smith DJ, Hammond DR, Whitty JPM. Influence of microvascular sutures on shear strain rate in realistic pulsatile flow. Microvasc Res 2018. [PMID: 29522755 DOI: 10.1016/j.mvr.2018.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Arterial thrombus formation is directly related to the mechanical shear experienced by platelets within flow. High shear strain rates (SSRs) and large shear gradients cause platelet activation, aggregation and production of thrombus. This study, for the first time, investigates the influence of pulsatile flow on local haemodynamics within sutured microarterial anastomoses. We measured physiological arterial waveform velocities experimentally using Doppler ultrasound velocimetry, and a representative example was applied to a realistic sutured microarterial geometry. Computational geometries were created using measurements taken from sutured chicken femoral arteries. Arterial SSRs were predicted using computational fluid dynamics (CFD) software, to indicate the potential for platelet activation, deposition and thrombus formation. Predictions of steady and sinusoidal inputs were compared to analyse whether the addition of physiological pulse characteristics affects local intravascular flow characteristics. Simulations were designed to evaluate flow in pristine and hand-sutured microarterial anastomoses, each with a steady-state and sinusoidal pulse component. The presence of sutures increased SSRmax in the anastomotic region by factors of 2.1 and 2.3 in steady-state and pulsatile flows respectively, when compared to a pristine vessel. SSR values seen in these simulations are analogous to the presence of moderate arterial stenosis. Steady-state simulations, driven by a constant inflow velocity equal to the peak systolic velocity (PSV) of the measured pulsatile flow, underestimated SSRs by ∼ 9% in pristine, and ∼ 19% in sutured vessels compared with a realistic pulse. Sinusoidal flows, with equivalent frequency and amplitude to a measured arterial waveform, represent a slight improvement on steady-state simulations, but still SSRs are underestimated by 1-2%. We recommend using a measured arterial waveform, of the form presented here, for simulating pulsatile flows in vessels of this nature. Under realistic pulsatile flow, shear gradients across microvascular sutures are high, of the order ∼ 7.9 × 106 m-1 s-1, which may also be associated with activation of platelets and formation of aggregates.
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Affiliation(s)
- R A J Wain
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute of Translational Medicine, University of Birmingham, B15 2TT, UK; School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK; Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK.
| | - D J Smith
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute for Metabolism and Systems Research, University of Birmingham, B15 2TT, UK
| | - D R Hammond
- School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - J P M Whitty
- Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK
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155
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Yu K, Andruschak P, Yeh HH, Grecov D, Kizhakkedathu JN. Influence of dynamic flow conditions on adsorbed plasma protein corona and surface-induced thrombus generation on antifouling brushes. Biomaterials 2018; 166:79-95. [PMID: 29549767 DOI: 10.1016/j.biomaterials.2018.03.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/27/2018] [Accepted: 03/05/2018] [Indexed: 12/28/2022]
Abstract
The information regarding the nature of protein corona (and its changes) and cell binding on biomaterial surface under dynamic conditions is critical to dissect the mechanism of surface-induced thrombosis. In this manuscript, we investigated the nature of protein corona and blood cell binding in heparinized recalcified human plasma, platelet rich plasma and whole blood on three highly hydrophilic antifouling polymer brushes, (poly(N, N-dimethylacrylamide) (PDMA), poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and poly[N-(2-hydroxypropyl) methacrylamide] (PHPMA) using an in vitro blood loop model at comparable arterial and venous flow, and static conditions. A fluid dynamics model was used initially to better understand the resulting flow patterns in a vertical channel containing the substrates to arrive at the placement of the substrates within the blood loop. The protein binding on the brush modified substrates was determined using ellipsometry, fluorescence microscopy and the nature of the protein corona was investigated using mass spectrometry based proteomics. The flow elevated fouling on brush coated surface from blood. The extent of plasma protein adsorption and platelet adhesion onto PDMA brush was lower than other surfaces in both static and flow conditions. The profiles of adsorbed protein corona showed strong dependence on the test conditions (static vs. flow), and the chemistry of the polymer brushes. Specially, the PDMA brush under flow conditions was more enriched with coagulation proteins, complement proteins, vitronectin and fibronectin but was less enriched with serum albumin. Apolipoprotein B-100 and complement proteins were the most abundant proteins seen on PMPC and PHPMA surfaces under both flow and static conditions, respectively. Unlike PDMA brush, the flow conditions did not affect the composition of protein corona on PMPC and PHPMA brushes. The nature of the protein corona formed in flow conditions influenced the platelet and red blood cell binding. The dependence of shear stress on platelet adhesion from platelet rich plasma and whole blood highlights the contribution of red blood cells in enhancing platelet adhesion on the surface under high shear condition.
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Affiliation(s)
- Kai Yu
- Centre for Blood Research and Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Paula Andruschak
- Centre for Blood Research and Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Department of Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Han Hung Yeh
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Department of Mechanical Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Dana Grecov
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Department of Mechanical Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Jayachandran N Kizhakkedathu
- Centre for Blood Research and Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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156
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Otani T, Shindo T, Ii S, Hirata M, Wada S. Effect of Local Coil Density on Blood Flow Stagnation in Densely Coiled Cerebral Aneurysms: A Computational Study Using a Cartesian Grid Method. J Biomech Eng 2018; 140:2671737. [DOI: 10.1115/1.4039150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Indexed: 11/08/2022]
Abstract
Aneurysm recurrence is the most critical concern following coil embolization of a cerebral aneurysm. Adequate packing density (PD) and coil uniformity are believed necessary to achieve sufficient flow stagnation, which decreases the risk of aneurysm recurrence. The effect of coil distribution on the extent of flow stagnation, however, especially in cases of dense packing (high PD), has received less attention. Thus, the cause of aneurysm recurrence despite dense packing is still an open question. The primary aim of this study is to evaluate the effect of local coil density on the extent of blood flow stagnation in densely coiled aneurysms. For this purpose, we developed a robust computational framework to determine blood flow using a Cartesian grid method, by which the complex fluid pathways in coiled aneurysms could be flexibly treated using an implicit function. This tool allowed us to conduct blood flow analyses in two patient-specific geometries with 50 coil distribution patterns in each aneurysm at clinically adequate PD. The results demonstrated that dense packing in the aneurysm may not necessarily block completely the inflow into the aneurysm and local flow that formed in the neck region, whose strength was inversely related to this local PD. This finding suggests that local coil density in the neck region still plays an important role in disturbing the remaining local flow, which possibly prevents thrombus formation in a whole aneurysm sac, increasing the risk of aneurysm regrowth and subsequent recurrence.
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Affiliation(s)
- Tomohiro Otani
- Mem. ASME Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka-shi 560-8531, Osaka, Japan e-mail:
| | - Takuya Shindo
- Department of Systems Science, School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka-shi 560-8531, Osaka, Japan e-mail:
| | - Satoshi Ii
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka-shi 560-8531, Osaka, Japan e-mail:
| | - Masayuki Hirata
- Department of Neurosurgery, Graduate School of Medicine and Global Center for Medical Engineering and Informatics (MEI Center), Osaka University, 2-2 Yamadaoka, Suita-shi 560-0871, Osaka, Japan e-mail:
| | - Shigeo Wada
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamacho, Toyonaka-shi 560-8531, Osaka, Japan e-mail:
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157
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Impaired contraction of blood clots as a novel prothrombotic mechanism in systemic lupus erythematosus. Clin Sci (Lond) 2018; 132:243-254. [PMID: 29295895 DOI: 10.1042/cs20171510] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/13/2017] [Accepted: 01/01/2018] [Indexed: 11/17/2022]
Abstract
The aim of this work was to examine a possible role of clot contraction/retraction in thrombotic complications of systemic lupus erythematosus (SLE). Using a novel automated method, we investigated kinetics of clot contraction in the blood of 51 SLE patients and 60 healthy donors. The functionality of platelets in the SLE patients was assessed using flow cytometry by expression of P-selectin and fibrinogen-binding capacity. The rate and degree of clot contraction were significantly reduced in SLE patients compared with healthy subjects, especially in the patients with higher blood levels of anti-dsDNA antibodies. The reduced platelet contractility correlated with partial refractoriness of platelets isolated from the blood of SLE patients to stimulation induced by the thrombin receptor activating peptide. To test if the anti-dsDNA autoantibodies cause continuous platelet activation, followed by exhaustion and dysfunction of the cells, we added purified exogenous anti-dsDNA autoantibodies from SLE patients to normal blood before clotting. In support of this hypothesis, the antibodies first enhanced clot contraction and then suppressed it in a time-dependent manner. Importantly, a direct correlation of clot contraction parameters with the disease severity suggests that the reduced compactness of intravascular clots and thrombi could be a pathogenic factor in SLE that may exaggerate the impaired blood flow at the site of thrombosis. In conclusion, autoantibodies in SLE can affect platelet contractility, resulting in reduced ability of clots and thrombi to shrink in volume, which increases vessel obstruction and may aggravate the course and outcomes of thrombotic complications in SLE.
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158
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Oh SD, Oh SJ, Suh BJ, Shin JY, Park JK. Long-Term Survival of a Patient with Adenocarcinoma of the Esophagogastric Junction with a Portal Vein Tumor Thrombosis Who Underwent Palliative Total Gastrectomy: A Case Report. Case Rep Oncol 2017; 10:916-922. [PMID: 29279692 PMCID: PMC5731138 DOI: 10.1159/000481430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 09/12/2017] [Indexed: 12/04/2022] Open
Abstract
Portal vein tumor thrombosis (PVTT) with advanced gastric cancer is very rare; when it occurs, it exhibits aggressive growth and carries a poor prognosis. In addition, definitive treatment has not been established due to insufficient data. Herein, we report a case of PVTT associated with an adenocarcinoma of the esophagogastric junction that was successfully controlled by means of a palliative total gastrectomy without surgical resection of the PVTT and administration of palliative continuous doxifluridine.
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Affiliation(s)
- Sung Don Oh
- Department of Surgery, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Sung Jin Oh
- Department of Surgery, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Byoung Jo Suh
- Department of Surgery, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Jin Yong Shin
- Department of Surgery, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Jong Kwon Park
- Department of Surgery, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
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159
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Modeling blood flow around a thrombus using a hybrid particle–continuum approach. Biomech Model Mechanobiol 2017; 17:645-663. [DOI: 10.1007/s10237-017-0983-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 11/09/2017] [Indexed: 10/18/2022]
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160
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Peng L, Qiu Y, Huang Z, Xia C, Dai C, Zheng T, Li Z. Numerical Simulation of Hemodynamic Changes in Central Veins after Tunneled Cuffed Central Venous Catheter Placement in Patients under Hemodialysis. Sci Rep 2017; 7:15955. [PMID: 29162830 PMCID: PMC5698485 DOI: 10.1038/s41598-017-12456-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 09/08/2017] [Indexed: 02/05/2023] Open
Abstract
The tunneled central venous catheter (CVC) plays an important role for hemodialysis patients, but CVC-related thrombosis in the central veins remain problematic. This study is the first try to numerically find out what hemodynamic parameters are predisposed to the initiation and formation of thrombus after CVC insertion. And the potential relationship between hemodynamic parameters and the incidence rates of thrombosis occurrence was explored. The results revealed that the CVC insertion led to a significant increase of hydraulic resistance, wide-ranging abnormally high wall shear stress (WSS), and a great loss of flow rotation in the vein. Moreover, the clinical data showed that thrombosis mainly occurred at sections where most blood flow lost spiral rotation after the CVC insertion, but no corresponding match was observed between the occurrence of thrombosis and the flow velocity or WSS. We speculate that the destruction of the flow rotation in the central vein is a precursor to the thrombus formation around CVC, and an introduction of spiral flow with the CVC insertion may possibly help to protect the central vein from thrombosis. Further animal and clinical experiments should be carried out to test and verify this speculation.
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Affiliation(s)
- Liqing Peng
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yue Qiu
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Zhongyi Huang
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Chunchao Xia
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, 610041, China
- Vascular Surgery Department, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Chenzhong Dai
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China.
| | - Zhenlin Li
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, 610041, China.
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161
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Mukherjee D, Jani ND, Selvaganesan K, Weng CL, Shadden SC. Computational Assessment of the Relation Between Embolism Source and Embolus Distribution to the Circle of Willis for Improved Understanding of Stroke Etiology. J Biomech Eng 2017; 138:2531719. [PMID: 27367268 DOI: 10.1115/1.4033986] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Indexed: 11/08/2022]
Abstract
Stroke caused by an embolism accounts for about a third of all stroke cases. Understanding the source and cause of the embolism is critical for diagnosis and long-term treatment of such stroke cases. The complex nature of the transport of an embolus within large arteries is a primary hindrance to a clear understanding of embolic stroke etiology. Recent advances in medical image-based computational hemodynamics modeling have rendered increasing utility to such techniques as a probe into the complex flow and transport phenomena in large arteries. In this work, we present a novel, patient-specific, computational framework for understanding embolic stroke etiology, by combining image-based hemodynamics with discrete particle dynamics and a sampling-based analysis. The framework allows us to explore the important question of how embolism source manifests itself in embolus distribution across the various major cerebral arteries. Our investigations illustrate prominent numerical evidence regarding (i) the size/inertia-dependent trends in embolus distribution to the brain; (ii) the relative distribution of cardiogenic versus aortogenic emboli among the anterior, middle, and posterior cerebral arteries; (iii) the left versus right brain preference in cardio-emboli and aortic-emboli transport; and (iv) the source-destination relationship for embolisms affecting the brain.
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162
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Ciciliano JC, Abbaspour R, Woodall J, Wu C, Bakir MS, Lam WA. Probing blood cell mechanics of hematologic processes at the single micron level. LAB ON A CHIP 2017; 17:3804-3816. [PMID: 29052682 DOI: 10.1039/c7lc00720e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Blood cells circulate in a dynamic fluidic environment, and during hematologic processes such as hemostasis, thrombosis, and inflammation, blood cells interact biophysically with a myriad of vascular matrices-blood clots and the subendothelial matrix. While it is known that adherent cells physiologically respond to the mechanical properties of their underlying matrices, how blood cells interact with their mechanical microenvironment of vascular matrices remains poorly understood. To that end, we developed microfluidic systems that achieve high fidelity, high resolution, single-micron PDMS features that mimic the physical geometries of vascular matrices. With these electron beam lithography (EBL)-based microsystems, the physical interactions of individual blood cells with the mechanical properties of the matrices can be directly visualized. We observe that the physical presence of the matrix, in and of itself, mediates hematologic processes of the three major blood cell types: platelets, erythrocytes, and leukocytes. First, we find that the physical presence of single micron micropillars creates a shear microgradient that is sufficient to cause rapid, localized platelet adhesion and aggregation that leads to complete microchannel occlusion; this response is enhanced with the presence of fibrinogen or collagen on the micropillar surface. Second, we begin to describe the heretofore unknown biophysical parameters for the formation of schistocytes, pathologic erythrocyte fragments associated with various thrombotic microangiopathies (poorly understood, yet life-threatening blood disorders associated with microvascular thrombosis). Finally, we observe that the physical interactions with a vascular matrix is sufficient to cause neutrophils to form procoagulant neutrophil extracellular trap (NET)-like structures. By combining electron beam lithography (EBL), photolithography, and soft lithography, we thus create microfluidic devices that provide novel insight into the response of blood cells to the mechanical microenvironment of vascular matrices and have promise as research-enabling and diagnostic platforms.
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Affiliation(s)
- Jordan C Ciciliano
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
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163
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Martinez AF, McMahon RD, Horner M, Miller WM. A uniform-shear rate microfluidic bioreactor for real-time study of proplatelet formation and rapidly-released platelets. Biotechnol Prog 2017; 33:1614-1629. [PMID: 28960897 DOI: 10.1002/btpr.2563] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/05/2017] [Indexed: 12/17/2022]
Abstract
Platelet transfusions, with profound clinical importance in blood clotting and wound healing, are entirely derived from human volunteer donors. Hospitals rely on a steady supply of donations, but these methods are limited by a 5-day shelf life, the potential risk of contamination, and differences in donor/recipient histocompatibility. These challenges invite the opportunity to generate platelets ex vivo. Although much progress has been made in generating large numbers of culture-derived megakaryocytes (Mks, the precursor cells to platelets), stimulating a high percentage of Mks to undergo platelet release remains a major challenge. Recent studies have demonstrated the utility of shear forces to enhance platelet release from cultured Mks. In this study, we performed a computational fluid dynamics (CFD) analysis of several published platelet microbioreactor systems, and used the results to develop a new 7-µm slit bioreactor-with well-defined flow patterns and uniform shear profiles. This uniform-shear-rate bioreactor (USRB-7µm) permits real-time visualization of the proplatelet (proPLT) formation process and the rapid-release of individual platelet-like-particles (PLPs), which has been observed in vivo, but not previously reported for platelet bioreactors. We showed that modulating shear forces and flow patterns had an immediate and significant impact on PLP generation. Surprisingly, using a single flow instead of dual flows led to an unexpected six-fold increase in PLP production. By identifying particularly effective operating conditions within a physiologically relevant environment, this USRB-7µm will be a useful tool for the study and analysis of proPLT/PLP formation that will further understanding of how to increase ex vivo platelet release. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1614-1629, 2017.
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Affiliation(s)
- Andres F Martinez
- Dept. of Chemical and Biological Engineering, Northwestern University, Evanston, IL, 60208
| | - Richard D McMahon
- Master of Biotechnology Program, Northwestern University, Evanston, IL, 60208
| | | | - William M Miller
- Dept. of Chemical and Biological Engineering, Master of Biotechnology Program, Northwestern University, Evanston, IL, 60208
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164
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Boersen JT, Groot Jebbink E, Van de Velde L, Versluis M, Lajoinie G, Slump CH, de Vries JPPM, Reijnen MMPJ. The Influence of Positioning of the Nellix Endovascular Aneurysm Sealing System on Suprarenal and Renal Flow: An In Vitro Study. J Endovasc Ther 2017; 24:677-687. [DOI: https:/doi.org/10.1177/1526602817719465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Purpose: To examine the influence of device positioning and infrarenal neck diameter on flow patterns in the Nellix endovascular aneurysm sealing (EVAS) system. Methods: The transition of the aortic flow lumen into two 10-mm-diameter stents after EVAS creates a mismatched area. Flow recirculation may affect local wall shear stress (WSS) profiles and residence time associated with atherosclerosis and thrombosis. To examine these issues, 7 abdominal aortic aneurysm flow phantoms were created, including 3 unstented controls and 3 stented models with infrarenal neck diameters of 24, 28, and 32 mm. Stents were positioned within the instructions for use (IFU). Another 28-mm model was created to evaluate lower positioning of the stents outside the IFU (28-mm LP). Flow was visualized using optical particle imaging velocimetry (PIV) and quantified by time-averaged WSS (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) in the aorta at the anteroposterior (AP) midplane, lateral midplane, and renal artery AP midplane levels. Results: Flow in the aorta AP midplane was similar in all models. Vortices were observed in the stented models in the lateral midplane near the anterior and posterior walls. In the 32-mm IFU and 28-mm LP models, a steady state of vortices appeared, with varying location during a cycle. In all models, a low TAWSS (<10−2 Pa) was observed at the anterior wall of the aorta with peak OSI of 0.5 and peak RRT of 104 Pa−1. This region was more proximally located in the stented models. The 24- and 28-mm IFU models showed flow with a higher velocity at the renal artery inflow compared to controls. TAWSS in the renal artery was lower near the orifice in all models, with the largest area in the 24-mm IFU model. OSI and RRT in the renal artery were near zero for all models. Conclusion: EVAS enhances vorticity proximal to the seal zone, especially with lower positioning of the device and in larger neck diameters. Endobags just below the renal artery affect the flow profile in a minor area of this artery in 24- and 28-mm necks, while lower stent positioning does not influence the renal artery flow profile.
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Affiliation(s)
- Johannes T. Boersen
- Department of Surgery, Rijnstate Hospital, Arnhem, the Netherlands
- Department of Vascular Surgery, St Antonius Hospital, Nieuwegein, the Netherlands
| | - Erik Groot Jebbink
- Department of Surgery, Rijnstate Hospital, Arnhem, the Netherlands
- Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, the Netherlands
| | | | - Michel Versluis
- Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, the Netherlands
- MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, the Netherlands
| | - Guillaume Lajoinie
- Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, the Netherlands
| | - Cornelius H. Slump
- MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, the Netherlands
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165
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Tricarico R, He Y, Laquian L, Scali ST, Tran-Son-Tay R, Beck AW, Berceli SA. Hemodynamic and Anatomic Predictors of Renovisceral Stent-Graft Occlusion Following Chimney Endovascular Repair of Juxtarenal Aortic Aneurysms. J Endovasc Ther 2017; 24:880-888. [PMID: 28914135 DOI: 10.1177/1526602817731096] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To identify anatomic and hemodynamic changes associated with impending visceral chimney stent-graft occlusion after endovascular aneurysm repair (EVAR) with the chimney technique (chEVAR). METHODS A retrospective evaluation was performed of computed tomography scans from 41 patients who underwent juxtarenal chEVAR from 2008 to 2012 to identify stent-grafts demonstrating conformational changes following initial placement. Six subjects (mean age 74 years; 3 men) were selected for detailed reconstruction and computational hemodynamic analysis; 4 had at least 1 occluded chimney stent-graft. This subset of repairs was systematically analyzed to define the anatomic and hemodynamic impact of these changes and identify signature patterns associated with impending renovisceral stent-graft occlusion. Spatial and temporal analyses of cross-sectional area, centerline angle, intraluminal pressure, and wall shear stress (WSS) were performed within the superior mesenteric and renal artery chimney grafts used for repair. RESULTS Conformational changes in the chimney stent-grafts and associated perturbations, in both local WSS and pressure, were responsible for the 5 occlusions in the 13 stented branches. Anatomic and hemodynamic signatures leading to occlusion were identified within 1 month postoperatively, with a lumen area <14 mm2 (p=0.04), systolic pressure gradient >25 Pa/mm (p=0.03), and systolic WSS >45 Pa (p=0.03) associated with future chimney stent-graft occlusion. CONCLUSION Chimney stent-grafts at increased risk for occlusion demonstrated anatomic and hemodynamic signatures within 1 month of juxtarenal chEVAR. Analysis of these parameters in the early postoperative period may be useful for identifying and remediating these high-risk stent-grafts.
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Affiliation(s)
- Rosamaria Tricarico
- 1 Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Yong He
- 2 North Florida/South Georgia Veterans Health System, University of Florida, Gainesville, FL, USA.,3 Department of Surgery, University of Florida, Gainesville, FL, USA
| | - Liza Laquian
- 3 Department of Surgery, University of Florida, Gainesville, FL, USA
| | - Salvatore T Scali
- 2 North Florida/South Georgia Veterans Health System, University of Florida, Gainesville, FL, USA.,3 Department of Surgery, University of Florida, Gainesville, FL, USA
| | - Roger Tran-Son-Tay
- 1 Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.,4 Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA
| | - Adam W Beck
- 5 University of Alabama School of Medicine, Birmingham, AL, USA
| | - Scott A Berceli
- 1 Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.,2 North Florida/South Georgia Veterans Health System, University of Florida, Gainesville, FL, USA.,3 Department of Surgery, University of Florida, Gainesville, FL, USA
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166
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Haynes LM, Orfeo T, Mann KG, Everse SJ, Brummel-Ziedins KE. Probing the Dynamics of Clot-Bound Thrombin at Venous Shear Rates. Biophys J 2017; 112:1634-1644. [PMID: 28445754 DOI: 10.1016/j.bpj.2017.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/28/2017] [Accepted: 03/01/2017] [Indexed: 02/07/2023] Open
Abstract
In closed system models of fibrin formation, exosite-mediated thrombin binding to fibrin contributes to clot stability and is resistant to inhibition by antithrombin/heparin while still susceptible to small, active-site inhibitors. Each molecule of fibrin can bind ∼1.6 thrombin molecules at low-affinity binding sites (Kd = 2.8 μM) and ∼0.3 molecules of thrombin at high-affinity binding sites (Kd = 0.15 μM). The goal of this study is to assess the stability of fibrin-bound thrombin under venous flow conditions and to determine both its accessibility and susceptibility to inhibition. A parallel-plate flow chamber (7 × 50 × 0.25 mm) for studying the stability of thrombin (0-1400 nM) adhered to a fibrin matrix (0.1-0.4 mg/mL fibrinogen, 10 nM thrombin) under a variety of venous flow conditions was developed using the thrombin-specific, fluorogenic substrate SN-59 (100 μM). The flow within this system is laminar (Re < 1) and reaction rates are driven by enzyme kinetics (Pe = 100, Da = 7000). A subpopulation of active thrombin remains stably adhered to a fibrin matrix over a range of venous shear rates (46-184 s-1) for upwards of 30 min, and this population is saturable at loads >500 nM and sensitive to the initial fibrinogen concentration. These observations were also supported by a mathematical model of thrombin adhesion to fibrin, which demonstrates that thrombin initially binds to the low-affinity thrombin binding sites before preferentially equilibrating to higher affinity sites. Antithrombin (2.6 μM) plus heparin (4 U/mL) inhibits 72% of the active clot-bound thrombin after ∼10 min at 92 s-1, while no inhibition is observed in the absence of heparin. Dabigatran (20 and 200 nM) inhibits (50 and 93%) clot-bound thrombin reversibly (87 and 66% recovery). This model illustrates that clot-bound thrombin stability is the result of a constant rearrangement of thrombin molecules within a dense matrix of binding sites.
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Affiliation(s)
- Laura M Haynes
- Department of Biochemistry, Robert Larner M.D. College of Medicine, University of Vermont, Colchester, Vermont
| | - Thomas Orfeo
- Department of Biochemistry, Robert Larner M.D. College of Medicine, University of Vermont, Colchester, Vermont
| | | | - Stephen J Everse
- Department of Biochemistry, Robert Larner M.D. College of Medicine, University of Vermont, Colchester, Vermont
| | - Kathleen E Brummel-Ziedins
- Department of Biochemistry, Robert Larner M.D. College of Medicine, University of Vermont, Colchester, Vermont.
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167
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Boersen JT, Groot Jebbink E, Van de Velde L, Versluis M, Lajoinie G, Slump CH, de Vries JPPM, Reijnen MMPJ. The Influence of Positioning of the Nellix Endovascular Aneurysm Sealing System on Suprarenal and Renal Flow: An In Vitro Study. J Endovasc Ther 2017; 24:677-687. [PMID: 28689483 DOI: 10.1177/1526602817719465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To examine the influence of device positioning and infrarenal neck diameter on flow patterns in the Nellix endovascular aneurysm sealing (EVAS) system. METHODS The transition of the aortic flow lumen into two 10-mm-diameter stents after EVAS creates a mismatched area. Flow recirculation may affect local wall shear stress (WSS) profiles and residence time associated with atherosclerosis and thrombosis. To examine these issues, 7 abdominal aortic aneurysm flow phantoms were created, including 3 unstented controls and 3 stented models with infrarenal neck diameters of 24, 28, and 32 mm. Stents were positioned within the instructions for use (IFU). Another 28-mm model was created to evaluate lower positioning of the stents outside the IFU (28-mm LP). Flow was visualized using optical particle imaging velocimetry (PIV) and quantified by time-averaged WSS (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) in the aorta at the anteroposterior (AP) midplane, lateral midplane, and renal artery AP midplane levels. RESULTS Flow in the aorta AP midplane was similar in all models. Vortices were observed in the stented models in the lateral midplane near the anterior and posterior walls. In the 32-mm IFU and 28-mm LP models, a steady state of vortices appeared, with varying location during a cycle. In all models, a low TAWSS (<10-2 Pa) was observed at the anterior wall of the aorta with peak OSI of 0.5 and peak RRT of 104 Pa-1. This region was more proximally located in the stented models. The 24- and 28-mm IFU models showed flow with a higher velocity at the renal artery inflow compared to controls. TAWSS in the renal artery was lower near the orifice in all models, with the largest area in the 24-mm IFU model. OSI and RRT in the renal artery were near zero for all models. CONCLUSION EVAS enhances vorticity proximal to the seal zone, especially with lower positioning of the device and in larger neck diameters. Endobags just below the renal artery affect the flow profile in a minor area of this artery in 24- and 28-mm necks, while lower stent positioning does not influence the renal artery flow profile.
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Affiliation(s)
- Johannes T Boersen
- 1 Department of Surgery, Rijnstate Hospital, Arnhem, the Netherlands.,2 Department of Vascular Surgery, St Antonius Hospital, Nieuwegein, the Netherlands
| | - Erik Groot Jebbink
- 1 Department of Surgery, Rijnstate Hospital, Arnhem, the Netherlands.,3 Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, the Netherlands
| | | | - Michel Versluis
- 3 Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, the Netherlands.,4 MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, the Netherlands
| | - Guillaume Lajoinie
- 3 Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, the Netherlands
| | - Cornelius H Slump
- 4 MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, the Netherlands
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168
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Groot Jebbink E, Mathai V, Boersen JT, Sun C, Slump CH, Goverde PC, Versluis M, Reijnen MM. Hemodynamic comparison of stent configurations used for aortoiliac occlusive disease. J Vasc Surg 2017; 66:251-260.e1. [DOI: 10.1016/j.jvs.2016.07.128] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/27/2016] [Indexed: 10/20/2022]
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169
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Pompano RR, Chiang AH, Kastrup CJ, Ismagilov RF. Conceptual and Experimental Tools to Understand Spatial Effects and Transport Phenomena in Nonlinear Biochemical Networks Illustrated with Patchy Switching. Annu Rev Biochem 2017; 86:333-356. [PMID: 28654324 PMCID: PMC10852032 DOI: 10.1146/annurev-biochem-060815-014207] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many biochemical systems are spatially heterogeneous and exhibit nonlinear behaviors, such as state switching in response to small changes in the local concentration of diffusible molecules. Systems as varied as blood clotting, intracellular calcium signaling, and tissue inflammation are all heavily influenced by the balance of rates of reaction and mass transport phenomena including flow and diffusion. Transport of signaling molecules is also affected by geometry and chemoselective confinement via matrix binding. In this review, we use a phenomenon referred to as patchy switching to illustrate the interplay of nonlinearities, transport phenomena, and spatial effects. Patchy switching describes a change in the state of a network when the local concentration of a diffusible molecule surpasses a critical threshold. Using patchy switching as an example, we describe conceptual tools from nonlinear dynamics and chemical engineering that make testable predictions and provide a unifying description of the myriad possible experimental observations. We describe experimental microfluidic and biochemical tools emerging to test conceptual predictions by controlling transport phenomena and spatial distribution of diffusible signals, and we highlight the unmet need for in vivo tools.
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Affiliation(s)
- Rebecca R Pompano
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904;
| | - Andrew H Chiang
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637;
| | - Christian J Kastrup
- Michael Smith Laboratories and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada;
| | - Rustem F Ismagilov
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125;
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170
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Shojaee M, Bashur CA. Compositions Including Synthetic and Natural Blends for Integration and Structural Integrity: Engineered for Different Vascular Graft Applications. Adv Healthc Mater 2017; 6. [PMID: 28371505 DOI: 10.1002/adhm.201700001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 02/13/2017] [Indexed: 11/07/2022]
Abstract
Tissue engineering approaches for small-diameter arteries require a scaffold that simultaneously maintains patency by preventing thrombosis and intimal hyperplasia, maintains its structural integrity after grafting, and allows integration. While synthetic and extracellular matrix-derived materials can provide some of these properties individually, developing a scaffold that provides the balanced properties needed for vascular graft survival in the clinic has been particularly challenging. After 30 years of research, there are now several scaffolds currently in clinical trials. However, these products are either being investigated for large-diameter applications or they require pre-seeding of endothelial cells. This progress report identifies important challenges unique to engineering vascular grafts for high pressure arteries less than 4 mm in diameter (e.g., coronary artery), and discusses limitations with the current usage of the term "small-diameter." Next, the composition and processing techniques used for generating tissue engineered vascular grafts (TEVGs) are discussed, with a focus on the benefits of blended materials. Other scaffolds for non-tissue engineering approaches and stents are also briefly mentioned for comparison. Overall, this progress report discusses the importance of defining the most critical challenges for small diameter TEVGs, developing new scaffolds to provide these properties, and determining acceptable benchmarks for scaffold responses in the body.
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171
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Comiskey PM, Yarin AL, Attinger D. High-speed video analysis of forward and backward spattered blood droplets. Forensic Sci Int 2017; 276:134-141. [PMID: 28535429 DOI: 10.1016/j.forsciint.2017.04.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/16/2017] [Accepted: 04/23/2017] [Indexed: 01/25/2023]
Abstract
High-speed videos of blood spatter due to a gunshot taken by the Ames Laboratory Midwest Forensics Resource Center (MFRC) [1] are analyzed. The videos used in this analysis were focused on a variety of targets hit by a bullet which caused either forward, backward, or both types of blood spatter. The analysis process utilized particle image velocimetry (PIV) and particle analysis software to measure drop velocities as well as the distributions of the number of droplets and their respective side view area. The results of this analysis revealed that the maximal velocity in the forward spatter can be about 47±5m/s and for the backward spatter - about 24±8m/s. Moreover, our measurements indicate that the number of droplets produced is larger in forward spatter than it is in backward spatter. In the forward and backward spatter the droplet area in the side-view images is approximately the same. The upper angles of the close-to-cone domain in which droplets are issued in forward and backward spatter are, 27±9° and 57±7°, respectively, whereas the lower angles of the close-to-cone domain are 28±12° and 30±18°, respectively. The inclination angle of the bullet as it penetrates the target is seen to play a large role in the directional preference of the spattered blood. Also, muzzle gases, bullet impact angle, as well as the aerodynamic wake of the bullet are seen to greatly influence the flight of the droplets. The intent of this investigation is to provide a quantitative basis for current and future research on bloodstain pattern analysis (BPA) of either forward or backward blood spatter due to a gunshot.
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Affiliation(s)
- P M Comiskey
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, 842 W. Taylor St., Chicago, IL 60607-7022, USA
| | - A L Yarin
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, 842 W. Taylor St., Chicago, IL 60607-7022, USA.
| | - D Attinger
- Department of Mechanical Engineering, Iowa State University, 2529 Union Dr., Ames, IA 60011-1210, USA
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172
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Lukas K, Stadtherr K, Gessner A, Wehner D, Schmid T, Wendel HP, Schmid C, Lehle K. Effect of Immobilized Antithrombin III on the Thromboresistance of Polycarbonate Urethane. MATERIALS 2017; 10:ma10040335. [PMID: 28772696 PMCID: PMC5506919 DOI: 10.3390/ma10040335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/28/2017] [Accepted: 03/21/2017] [Indexed: 11/16/2022]
Abstract
The surface of foils and vascular grafts made from a thermoplastic polycarbonate urethanes (PCU) (Chronoflex AR) were chemically modified using gas plasma treatment, binding of hydrogels—(1) polyethylene glycol bisdiamine and carboxymethyl dextran (PEG-DEX) and (2) polyethyleneimine (PEI)—and immobilization of human antithrombin III (AT). Their biological impact was tested in vitro under static and dynamic conditions. Static test methods showed a significantly reduced adhesion of endothelial cells, platelets, and bacteria, compared to untreated PCU. Modified PCU grafts were circulated in a Chandler-Loop model for 90 min at 37 °C with human blood. Before and after circulation, parameters of the hemostatic system (coagulation, platelets, complement, and leukocyte activation) were analyzed. PEI-AT significantly inhibited the activation of both coagulation and platelets and prevented the activation of leukocytes and complement. In conclusion, both modifications significantly reduce coagulation activation, but only PEI-AT creates anti-bacterial and anti-thrombogenic functionality.
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Affiliation(s)
- Karin Lukas
- IMHR, Institute for Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany.
| | - Karin Stadtherr
- IMHR, Institute for Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany.
| | - Andre Gessner
- IMHR, Institute for Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany.
| | - Daniel Wehner
- Dualis Medtech GmbH, Am Technologiepark 8+10, 82229 Seefeld, Germany.
| | - Thomas Schmid
- Dualis Medtech GmbH, Am Technologiepark 8+10, 82229 Seefeld, Germany.
| | - Hans Peter Wendel
- Department of Thoracic, Cardiac, and Vascular Surgery, University Hospital Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
| | - Christof Schmid
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, Josef-Strauss-Allee 11, 93042 Regensburg, Germany.
| | - Karla Lehle
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, Josef-Strauss-Allee 11, 93042 Regensburg, Germany.
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173
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Boersen JT, Groot Jebbink E, Versluis M, Slump CH, Ku DN, de Vries JPPM, Reijnen MMPJ. Flow and wall shear stress characterization after endovascular aneurysm repair and endovascular aneurysm sealing in an infrarenal aneurysm model. J Vasc Surg 2017; 66:1844-1853. [PMID: 28285931 DOI: 10.1016/j.jvs.2016.10.077] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 10/10/2016] [Indexed: 11/17/2022]
Abstract
BACKGROUND Endovascular aneurysm repair (EVAR) with a modular endograft has become the preferred treatment for abdominal aortic aneurysms. A novel concept is endovascular aneurysm sealing (EVAS), consisting of dual endoframes surrounded by polymer-filled endobags. This dual-lumen configuration is different from a bifurcation with a tapered trajectory of the flow lumen into the two limbs and may induce unfavorable flow conditions. These include low and oscillatory wall shear stress (WSS), linked to atherosclerosis, and high shear rates that may result in thrombosis. An in vitro study was performed to assess the impact of EVAR and EVAS on flow patterns and WSS. METHODS Four abdominal aortic aneurysm phantoms were constructed, including three stented models, to study the influence of the flow divider on flow (Endurant [Medtronic, Minneapolis, Minn], AFX [Endologix, Irvine, Calif], and Nellix [Endologix]). Experimental models were tested under physiologic resting conditions, and flow was visualized with laser particle imaging velocimetry, quantified by shear rate, WSS, and oscillatory shear index (OSI) in the suprarenal aorta, renal artery (RA), and common iliac artery. RESULTS WSS and OSI were comparable for all models in the suprarenal aorta. The RA flow profile in the EVAR models was comparable to the control, but a region of lower WSS was observed on the caudal wall compared with the control. The EVAS model showed a stronger jet flow with a higher shear rate in some regions compared with the other models. Small regions of low WSS and high OSI were found near the distal end of all stents in the common iliac artery compared with the control. Maximum shear rates in each region of interest were well below the pathologic threshold for acute thrombosis. CONCLUSIONS The different stent designs do not influence suprarenal flow. Lower WSS is observed in the caudal wall of the RA after EVAR and a higher shear rate after EVAS. All stented models have a small region of low WSS and high OSI near the distal outflow of the stents.
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Affiliation(s)
- Johannes T Boersen
- Department of Surgery, Rijnstate Hospital, Arnhem, The Netherlands; Department of Vascular Surgery, St. Antonius Hospital, Nieuwegein, The Netherlands; Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, The Netherlands.
| | - Erik Groot Jebbink
- Department of Surgery, Rijnstate Hospital, Arnhem, The Netherlands; Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, The Netherlands
| | - Michel Versluis
- Department of Physics of Fluids, Faculty of Science and Technology, Technical University of Twente, Enschede, The Netherlands
| | - Cornelis H Slump
- MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - David N Ku
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Ga
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174
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Yeon JH, Mazinani N, Schlappi TS, Chan KYT, Baylis JR, Smith SA, Donovan AJ, Kudela D, Stucky GD, Liu Y, Morrissey JH, Kastrup CJ. Localization of Short-Chain Polyphosphate Enhances its Ability to Clot Flowing Blood Plasma. Sci Rep 2017; 7:42119. [PMID: 28186112 PMCID: PMC5301195 DOI: 10.1038/srep42119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/04/2017] [Indexed: 11/09/2022] Open
Abstract
Short-chain polyphosphate (polyP) is released from platelets upon platelet activation, but it is not clear if it contributes to thrombosis. PolyP has increased propensity to clot blood with increased polymer length and when localized onto particles, but it is unknown whether spatial localization of short-chain polyP can accelerate clotting of flowing blood. Here, numerical simulations predicted the effect of localization of polyP on clotting under flow, and this was tested in vitro using microfluidics. Synthetic polyP was more effective at triggering clotting of flowing blood plasma when localized on a surface than when solubilized in solution or when localized as nanoparticles, accelerating clotting at 10-200 fold lower concentrations, particularly at low to sub-physiological shear rates typical of where thrombosis occurs in large veins or valves. Thus, sub-micromolar concentrations of short-chain polyP can accelerate clotting of flowing blood plasma under flow at low to sub-physiological shear rates. However, a physiological mechanism for the localization of polyP to platelet or vascular surfaces remains unknown.
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Affiliation(s)
- Ju Hun Yeon
- Michael Smith Laboratories and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Nima Mazinani
- Michael Smith Laboratories and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Travis S Schlappi
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Karen Y T Chan
- Michael Smith Laboratories and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - James R Baylis
- Michael Smith Laboratories and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Stephanie A Smith
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Alexander J Donovan
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Damien Kudela
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Galen D Stucky
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Ying Liu
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - James H Morrissey
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Christian J Kastrup
- Michael Smith Laboratories and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
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175
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Alexopoulos SP, Nekrasov V, Cao S, Groshen S, Kaur N, Genyk YS, Matsuoka L. Effects of recipient size and allograft type on pediatric liver transplantation for biliary atresia. Liver Transpl 2017; 23:221-233. [PMID: 27862929 DOI: 10.1002/lt.24675] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/18/2016] [Indexed: 12/13/2022]
Abstract
The majority of pediatric patients with end-stage liver disease receive a transplant with a whole liver (WL) allograft. However, smaller recipients with biliary atresia (BA) may have improved outcomes with deceased donor partial liver (DDPL) or living donor allografts. This study compares the national outcomes for liver transplantation in BA, with attention to the interaction between liver allograft type and recipient size. From January 2, 2002 to December 30, 2014, 2123 pediatric patients underwent a primary liver transplant for BA. The majority of transplants (53%) were performed with a WL allograft. Utilization of a WL allograft increased from 42% of recipients weighing ≤ 7 kg to 74% of recipients weighing > 14 kg. The 1-, 5-, and 10-year graft survival in recipients weighing ≤7 kg was significantly superior for living donor liver transplantation (LDLT) (91%, 88%, 84%) and DDPL allografts (90%, 84%, 77%) compared with WL allografts (79%, 75%, 74%; P = 0.005). The 1-, 5-, and 10-year graft survival in recipients weighing >14 kg trended toward being inferior in recipients of DDPL allografts (85%, 85%, 71%) compared with WL allografts (96%, 91%, 86%; P = 0.06). Furthermore, the incidence of vascular thrombosis was highest in WL (13%) compared with LDLT (6%) and DDPL (5%) recipients ≤ 7 kg (P = 0.002). Liver retransplantation was also highest in WL (16%) compared with LDLT (9%) and DDPL (9%) recipients ≤ 7 kg (P = 0.02). In conclusion, strong consideration should be given to the use of technical variant allografts in small recipients with BA requiring liver transplantation. Liver Transplantation 23 221-233 2017 AASLD.
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Affiliation(s)
- Sophoclis P Alexopoulos
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Victor Nekrasov
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Shu Cao
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Susan Groshen
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Navpreet Kaur
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Yuri S Genyk
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Lea Matsuoka
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA
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176
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Arzani A, Gambaruto AM, Chen G, Shadden SC. Wall shear stress exposure time: a Lagrangian measure of near-wall stagnation and concentration in cardiovascular flows. Biomech Model Mechanobiol 2016; 16:787-803. [DOI: 10.1007/s10237-016-0853-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/08/2016] [Indexed: 12/18/2022]
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177
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Ko D, Thigpen JL, Otis JA, Forster K, Henault L, Quinn E, Tripodis Y, Berger PB, Limdi N, Hylek EM. Influence of statin therapy at time of stroke onset on functional outcome among patients with atrial fibrillation. Int J Cardiol 2016; 227:808-812. [PMID: 28273786 DOI: 10.1016/j.ijcard.2016.10.055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/19/2016] [Accepted: 10/22/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Statin pretreatment has been associated with reduced infarct volume in nonlacunar strokes. The effect of statins on functional outcomes of strokes related to atrial fibrillation (AF) is unknown. We aimed to define the influence of prestroke statin use on functional outcome in AF. METHODS We assembled a cohort of consecutive ischemic stroke patients from 2006 to 2010. All patients underwent CT or MRI and were adjudicated by site investigators. AF was confirmed by electrocardiogram in 100% of patients. Site neurologists blinded to the study hypothesis affirmed the type of stroke and assessed the severity of disability at the time of hospital discharge. The frequency of death at 30-days was calculated. RESULTS Ischemic stroke (n=1030) resulted in a severe neurological deficit or death (modified Rankin scale ≥4) at 30days in 711 patients (69%). Using multivariable logistic regression models adjusting for factors associated with statin treatment and factors associated with functional outcome, prestroke statin use was associated with a 32% reduction in frequency of severe stroke (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.50-0.92; P=0.011). Other independent factors associated with severe stroke included older age, female sex, non-White race, diabetes mellitus, prior ischemic stroke, prior venous thromboembolism, and dementia. CONCLUSION Ischemic strokes in AF are associated with high mortality and morbidity. Statin use at time of stroke onset among patients with AF was associated in this study with less severe stroke and warrant validation.
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Affiliation(s)
- Darae Ko
- Department of Medicine, Boston University School of Medicine, Boston, MA, United States.
| | - Jonathan L Thigpen
- Department of Clinical and Administrative Sciences, Notre Dame of Maryland School of Pharmacy, Baltimore, MD, United States
| | - James A Otis
- Department of Neurology, Boston University School of Medicine, Boston, MA, United States
| | - Kristen Forster
- Department of Cardiology, Geisinger Health System, Danville, PA, United States
| | - Lori Henault
- Department of Medicine, Boston University School of Medicine, Boston, MA, United States
| | - Emily Quinn
- Department of Biostatistics, Boston University School Public Health, Boston, MA, United States
| | - Yorghos Tripodis
- Department of Biostatistics, Boston University School Public Health, Boston, MA, United States
| | - Peter B Berger
- Department of Cardiology, Geisinger Health System, Danville, PA, United States
| | - Nita Limdi
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Elaine M Hylek
- Department of Medicine, Boston University School of Medicine, Boston, MA, United States
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178
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Zilberman-Rudenko J, Sylman JL, Lakshmanan HHS, McCarty OJT, Maddala J. Dynamics of blood flow and thrombus formation in a multi-bypass microfluidic ladder network. Cell Mol Bioeng 2016; 10:16-29. [PMID: 28580033 DOI: 10.1007/s12195-016-0470-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The reaction dynamics of a complex mixture of cells and proteins, such as blood, in branched circulatory networks within the human microvasculature or extravascular therapeutic devices such as extracorporeal oxygenation machine (ECMO) remains ill-defined. In this report we utilize a multi-bypass microfluidics ladder network design with dimensions mimicking venules to study patterns of blood platelet aggregation and fibrin formation under complex shear. Complex blood fluid dynamics within multi-bypass networks under flow were modeled using COMSOL. Red blood cells and platelets were assumed to be non-interacting spherical particles transported by the bulk fluid flow, and convection of the activated coagulation factor II, thrombin, was assumed to be governed by mass transfer. This model served as the basis for predicting formation of local shear rate gradients, stagnation points and recirculation zones as dictated by the bypass geometry. Based on the insights from these models, we were able to predict the patterns of blood clot formation at specific locations in the device. Our experimental data was then used to adjust the model to account for the dynamical presence of thrombus formation in the biorheology of blood flow. The model predictions were then compared to results from experiments using recalcified whole human blood. Microfluidic devices were coated with the extracellular matrix protein, fibrillar collagen, and the initiator of the extrinsic pathway of coagulation, tissue factor. Blood was perfused through the devices at a flow rate of 2 µL/min, translating to physiologically relevant initial shear rates of 300 and 700 s-1 for main channels and bypasses, respectively. Using fluorescent and light microscopy, we observed distinct flow and thrombus formation patterns near channel intersections at bypass points, within recirculation zones and at stagnation points. Findings from this proof-of-principle ladder network model suggest a specific correlation between microvascular geometry and thrombus formation dynamics under shear. This model holds potential for use as an integrative approach to identify regions susceptible to intravascular thrombus formation within the microvasculature as well as extravascular devices such as ECMO.
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Affiliation(s)
| | - Joanna L Sylman
- Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, OR
| | - Hari H S Lakshmanan
- Chemical and Biomedical Engineering, West Virginia University, Morgantown, WV
| | - Owen J T McCarty
- Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, OR
| | - Jeevan Maddala
- Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, OR
- Chemical and Biomedical Engineering, West Virginia University, Morgantown, WV
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179
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Holographic intravital microscopy for 2-D and 3-D imaging intact circulating blood cells in microcapillaries of live mice. Sci Rep 2016; 6:33084. [PMID: 27605489 PMCID: PMC5015119 DOI: 10.1038/srep33084] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/19/2016] [Indexed: 11/29/2022] Open
Abstract
Intravital microscopy is an essential tool that reveals behaviours of live cells under conditions close to natural physiological states. So far, although various approaches for imaging cells in vivo have been proposed, most require the use of labelling and also provide only qualitative imaging information. Holographic imaging approach based on measuring the refractive index distributions of cells, however, circumvent these problems and offer quantitative and label-free imaging capability. Here, we demonstrate in vivo two- and three-dimensional holographic imaging of circulating blood cells in intact microcapillaries of live mice. The measured refractive index distributions of blood cells provide morphological and biochemical properties including three-dimensional cell shape, haemoglobin concentration, and haemoglobin contents at the individual cell level. With the present method, alterations in blood flow dynamics in live healthy and sepsis-model mice were also investigated.
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180
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Papadopoulos KP, Gavaises M, Pantos I, Katritsis DG, Mitroglou N. Derivation of flow related risk indices for stenosed left anterior descending coronary arteries with the use of computer simulations. Med Eng Phys 2016; 38:929-39. [DOI: 10.1016/j.medengphy.2016.05.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/15/2016] [Accepted: 05/26/2016] [Indexed: 10/21/2022]
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181
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Matsunari Y, Sugimoto M, Doi M, Matsui H, Kawaguchi M. Functional characterization of tissue factor in von Willebrand factor-dependent thrombus formation under whole blood flow conditions. Int J Hematol 2016; 104:661-668. [PMID: 27562418 DOI: 10.1007/s12185-016-2086-z] [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: 05/24/2016] [Revised: 08/17/2016] [Accepted: 08/22/2016] [Indexed: 11/29/2022]
Abstract
Von Willebrand factor (VWF) plays an important role in mediating platelet adhesion and aggregation under high shear rate conditions. Such platelet aggregates are strengthened by fibrin-network formation triggered by tissue factor (TF). However, little is known about the role of TF in VWF-dependent thrombus formation under blood flow conditions. We evaluated TF in thrombus formation on immobilized VWF under whole blood flow conditions in an in vitro perfusion chamber system. Surface-immobilized TF amplified intra-thrombus fibrin generation significantly under both low and high shear flow conditions, while TF in sample blood showed no appreciable effects. Furthermore, immobilized TF enhanced VWF-dependent platelet adhesion and aggregation significantly under high shear rates. Neutrophil cathepsin G and elastase increased significantly intra-thrombus fibrin deposition on immobilized VWF-TF complex, suggesting the involvement of leukocyte inflammatory responses in VWF/TF-dependent mural thrombogenesis under these flow conditions. These results reveal a functional link between VWF and TF under whole blood flow conditions, in which surface-immobilized TF and VWF mutually contribute to mural thrombus formation, which is essential for normal hemostasis. By contrast, TF circulating in blood may be involved in systemic hypercoagulability, as seen in sepsis caused by severe microbial infection, in which neutrophil inflammatory responses may be active.
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Affiliation(s)
- Yasunori Matsunari
- Department of Anesthesiology, Nara Medical University, Kashihara, Nara, Japan
| | - Mitsuhiko Sugimoto
- Department of Regulatory Medicine for Thrombosis, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan.
| | - Masaaki Doi
- Department of Regulatory Medicine for Thrombosis, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Hideto Matsui
- Department of Regulatory Medicine for Thrombosis, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Masahiko Kawaguchi
- Department of Anesthesiology, Nara Medical University, Kashihara, Nara, Japan
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182
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Balaguru UM, Sundaresan L, Manivannan J, Majunathan R, Mani K, Swaminathan A, Venkatesan S, Kasiviswanathan D, Chatterjee S. Disturbed flow mediated modulation of shear forces on endothelial plane: A proposed model for studying endothelium around atherosclerotic plaques. Sci Rep 2016; 6:27304. [PMID: 27255968 PMCID: PMC4891674 DOI: 10.1038/srep27304] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 05/16/2016] [Indexed: 02/07/2023] Open
Abstract
Disturbed fluid flow or modulated shear stress is associated with vascular conditions such as atherosclerosis, thrombosis, and aneurysm. In vitro simulation of the fluid flow around the plaque micro-environment remains a challenging approach. Currently available models have limitations such as complications in protocols, high cost, incompetence of co-culture and not being suitable for massive expression studies. Hence, the present study aimed to develop a simple, versatile model based on Computational Fluid Dynamics (CFD) simulation. Current observations of CFD have shown the regions of modulated shear stress by the disturbed fluid flow. To execute and validate the model in real sense, cell morphology, cytoskeletal arrangement, cell death, reactive oxygen species (ROS) profile, nitric oxide production and disturbed flow markers under the above condition were assessed. Endothelium at disturbed flow region which had been exposed to low shear stress and swirling flow pattern showed morphological and expression similarities with the pathological disturbed flow environment reported previously. Altogether, the proposed model can serve as a platform to simulate the real time micro-environment of disturbed flow associated with eccentric plaque shapes and the possibilities of studying its downstream events.
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Affiliation(s)
- Uma Maheswari Balaguru
- Vascular Biology Lab, AU-KBC Research Centre, MIT campus of Anna University, Chennai, India
| | | | - Jeganathan Manivannan
- Vascular Biology Lab, AU-KBC Research Centre, MIT campus of Anna University, Chennai, India
| | - Reji Majunathan
- Vascular Biology Lab, AU-KBC Research Centre, MIT campus of Anna University, Chennai, India
| | - Krishnapriya Mani
- Vascular Biology Lab, AU-KBC Research Centre, MIT campus of Anna University, Chennai, India
| | - Akila Swaminathan
- Vascular Biology Lab, AU-KBC Research Centre, MIT campus of Anna University, Chennai, India
| | | | | | - Suvro Chatterjee
- Vascular Biology Lab, AU-KBC Research Centre, MIT campus of Anna University, Chennai, India.,Centre for Biotechnology, Anna University, Chennai, India
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183
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Zilberman-Rudenko J, Itakura A, Maddala J, Baker-Groberg SM, Vetter R, Tucker EI, Gruber A, Gerdes C, McCarty OJT. Biorheology of platelet activation in the bloodstream distal to thrombus formation. Cell Mol Bioeng 2016; 9:496-508. [PMID: 28083075 DOI: 10.1007/s12195-016-0448-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Thrombus growth at the site of vascular injury is mediated by the sequential events of platelet recruitment, activation and aggregation concomitant with the initiation of the coagulation cascade, resulting in local thrombin generation and fibrin formation. While the biorheology of a localized thrombus formation has been well studied, it is unclear whether local sites of thrombin generation propagate platelet activation within the bloodstream. In order to study the physical biology of platelet activation downstream of sites of thrombus formation, we developed a platform to measure platelet activation and microaggregate formation in the bloodstream. Our results show that thrombi formed on collagen and tissue factor promote activation and aggregation of platelets in the bloodstream in a convection-dependent manner. Pharmacological inhibition of the coagulation factors (F) X, XI or thrombin dramatically reduced the degree of distal platelet activation and microaggregate formation in the bloodstream without affecting the degree of local platelet deposition and aggregation on a surface of immobilized collagen. Herein we describe the development and an example of the utility of a platform to study platelet activation and microaggregate formation in the bloodstream (convection-limited regime) relative to the local site of thrombus formation.
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Affiliation(s)
- Jevgenia Zilberman-Rudenko
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, 3303 SW Bond Ave, Portland, OR, USA
| | - Asako Itakura
- Department of Cell, Developmental & Cancer Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA; Drug Discovery, Bayer Pharma AG, Wuppertal, Germany
| | - Jeevan Maddala
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, 3303 SW Bond Ave, Portland, OR, USA; Chemical and Biomedical Engineering, West Virginia University, Morgantown, WV
| | - Sandra M Baker-Groberg
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, 3303 SW Bond Ave, Portland, OR, USA
| | - Ralf Vetter
- Drug Discovery, Bayer Pharma AG, Wuppertal, Germany
| | - Erik I Tucker
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, 3303 SW Bond Ave, Portland, OR, USA; Division of Hematology / Medical Oncology, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - András Gruber
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, 3303 SW Bond Ave, Portland, OR, USA; Division of Hematology / Medical Oncology, School of Medicine, Oregon Health & Science University, Portland, OR, USA; Aronora Inc., Portland, OR, USA
| | | | - Owen J T McCarty
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, 3303 SW Bond Ave, Portland, OR, USA; Department of Cell, Developmental & Cancer Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA; Division of Hematology / Medical Oncology, School of Medicine, Oregon Health & Science University, Portland, OR, USA
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184
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In Vitro Thrombogenesis Resulting from Decreased Shear Rate and Blood Coagulability. Int J Artif Organs 2016; 39:194-9. [DOI: 10.5301/ijao.5000496] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2016] [Indexed: 11/20/2022]
Abstract
In vitro antithrombogenic testing with mock circulation is a useful type of pre-evaluation in ex vivo testing of mechanical assist devices. For effective in vitro testing, we have been developing a clear quantitative thrombogenesis model based on shear stress and blood coagulability. Bovine blood was used as the test medium. The activating clotting time (ACT) was adjusted with trisodium citrate and calcium chloride from 200 to 1,000 seconds. The blood was then applied to a rheometer and subjected to shear at 50 to 2,880 s-1. Blood coagulation time and degree of thrombogenesis were measured by the torque sensor of the rheometer. Prothrombin time (PT) and activated partial thromboplastin time (APTT) of the test blood were also measured after the application of shear. Blood coagulation time increased, and the degree of thrombogenesis decreased, with increases in shear rate to between 50 and 2,880 s-1. for test bloods with ACTs of 200 to 250 seconds. An ACT of 200 to 250 seconds is thus appropriate for in vitro antithrombogenic testing under a shear rate of 2,880 s-1. APTT was prolonged, whereas PT did not change, with increasing shear rate: that is, increasing the shear rate reduced thrombogenesis related to the intrinsic clotting pathway. An ACT of 200 to 250 seconds was suitable for in vitro antithrombogenic testing, and increasing the shear stress generated in the mechanical assist device reduced thrombogenesis via the intrinsic clotting pathway.
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185
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Microarterial anastomoses: A parameterised computational study examining the effect of suture position on intravascular blood flow. Microvasc Res 2016; 105:141-8. [DOI: 10.1016/j.mvr.2016.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 02/04/2016] [Accepted: 02/04/2016] [Indexed: 11/19/2022]
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186
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Kelchtermans H, Pelkmans L, Bouwhuis A, Schurgers E, Lindhout T, Huskens D, Miszta A, Hemker HC, Lancé MD, de Laat B. Simultaneous measurement of thrombin generation and fibrin formation in whole blood under flow conditions. Thromb Haemost 2016; 116:134-45. [PMID: 27074907 DOI: 10.1160/th15-10-0801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 03/28/2016] [Indexed: 11/05/2022]
Abstract
Assays based on the formation of thrombin and fibrin are frequently used, and results are considered exchangeable in research/clinical settings. However, thrombin generation and fibrin formation do not always go hand in hand and flow profoundly influences thrombus formation. We describe the technical/clinical evaluation of an assay to simultaneously measure thrombin generation and fibrin formation under conditions of flow. Introduction of a fluorometer into a 'cone and base principle'-based rheometer allowed the measurement of thrombin generation (using a thrombin-sensitive substrate) and fibrin formation (changes in viscosity), while applying a linear shear flow. Increasing shear rates inversely related with thrombin generation and fibrin formation. Increasing fibrinogen concentrations in defibrinated plasma resulted in increased thrombin generation and fibrin formation. In pre-operative samples of 70 patients undergoing cardiothoracic surgery, fibrin formation and thrombin generation parameters correlated with fibrinogen content, rotational thromboelastometry (ROTEM) and whole blood Calibrated Automated Thrombinography (CAT) parameters, respectively. Upon dividing patients into two groups based on the median clot strength, a significant difference in perioperative/total blood loss was established. In conclusion, we clinically evaluated a method capable of simultaneously measuring thrombin generation and fibrin formation in plasma/whole blood under continuous flow, rendering our method one step closer to physiology. Importantly, our test proved to be indicative for the amount of blood loss during/after cardiothoracic surgery.
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Affiliation(s)
- Hilde Kelchtermans
- Hilde Kelchtermans, Oxfordlaan 70, Maastricht 6229EV, The Netherlands, Tel.: +31 43 388 58 94, Fax: +31 43 388 45 70, E-mail:
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187
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Valerio L, Tran PL, Sheriff J, Brengle W, Ghosh R, Chiu WC, Redaelli A, Fiore GB, Pappalardo F, Bluestein D, Slepian MJ. Aspirin has limited ability to modulate shear-mediated platelet activation associated with elevated shear stress of ventricular assist devices. Thromb Res 2016; 140:110-117. [PMID: 26938158 DOI: 10.1016/j.thromres.2016.01.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 01/25/2016] [Accepted: 01/31/2016] [Indexed: 10/22/2022]
Abstract
Continuous flow ventricular assist devices (cfVADs) while effective in advanced heart failure, remain plagued by thrombosis related to abnormal flows and elevated shear stress. To limit cfVAD thrombosis, patients utilize complex anti-thrombotic regimens built upon a foundation of aspirin (ASA). While much data exists on ASA as a modulator of biochemically-mediated platelet activation, limited data exists as to the efficacy of ASA as a means of limiting shear-mediated platelet activation, particularly under elevated shear stress common within cfVADs. We investigated the ability of ASA (20, 25 and 125 μM) to limit shear-mediated platelet activation under conditions of: 1) constant shear stress (30 dynes/cm(2) and 70 dynes/cm(2)); 2) dynamic shear stress, and 3) initial high shear exposure (70 dynes/cm(2)) followed by low shear exposure - i.e. a platelet sensitization protocol, utilizing a hemodynamic shearing device providing uniform shear stress in vitro. The efficacy of ASA to limit platelet activation mediated via passage through a clinical cfVAD system (DeBakey Micromed) in vitro was also studied. ASA reduced platelet activation only under conditions of low shear stress (38% reduction compared to control, n=10, p<0.004), with minimal protection at higher shear stress and under dynamic conditions (n=10, p>0.5) with no limitation of platelet sensitization. ASA had limited ability (25.6% reduction in platelet activation rate) to modulate shear-mediated platelet activation induced via cfVAD passage. These findings, while performed under "deconstructed" non-clinical conditions by utilizing purified platelets alone in vitro, provide a potential contributory mechanistic explanation for the persistent thrombosis rates experienced clinically in cfVAD patients despite ASA therapy. An opportunity exists to develop enhanced pharmacologic strategies to limit shear-mediated platelet activation at elevated shear levels associated with mechanical circulatory support devices.
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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.
| | - Phat L Tran
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA
| | - Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - William Brengle
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA
| | - Ram Ghosh
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Wei-Che Chiu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 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, University of Arizona, Tucson, AZ, USA; Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, AZ, USA; Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
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188
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Brubert J, Krajewski S, Wendel HP, Nair S, Stasiak J, Moggridge GD. Hemocompatibility of styrenic block copolymers for use in prosthetic heart valves. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2016; 27:32. [PMID: 26704549 PMCID: PMC4690832 DOI: 10.1007/s10856-015-5628-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/12/2015] [Indexed: 06/05/2023]
Abstract
Certain styrenic thermoplastic block copolymer elastomers can be processed to exhibit anisotropic mechanical properties which may be desirable for imitating biological tissues. The ex-vivo hemocompatibility of four triblock (hard-soft-hard) copolymers with polystyrene hard blocks and polyethylene, polypropylene, polyisoprene, polybutadiene or polyisobutylene soft blocks are tested using the modified Chandler loop method using fresh human blood and direct contact cell proliferation of fibroblasts upon the materials. The hemocompatibility and durability performance of a heparin coating is also evaluated. Measures of platelet and coagulation cascade activation indicate that the test materials are superior to polyester but inferior to expanded polytetrafluoroethylene and bovine pericardium reference materials. Against inflammatory measures the test materials are superior to polyester and bovine pericardium. The addition of a heparin coating results in reduced protein adsorption and ex-vivo hemocompatibility performance superior to all reference materials, in all measures. The tested styrenic thermoplastic block copolymers demonstrate adequate performance for blood contacting applications.
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Affiliation(s)
- Jacob Brubert
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK.
| | - Stefanie Krajewski
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tuebingen, Tübingen, Germany
| | - Hans Peter Wendel
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tuebingen, Tübingen, Germany
| | - Sukumaran Nair
- Cardiothoracic Services, Freeman Hospital, Newcastle, UK
| | - Joanna Stasiak
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Geoff D Moggridge
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
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189
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Shi X, Yang J, Huang J, Long Z, Ruan Z, Xiao B, Xi X. Effects of different shear rates on the attachment and detachment of platelet thrombi. Mol Med Rep 2016; 13:2447-56. [PMID: 26847168 PMCID: PMC4768970 DOI: 10.3892/mmr.2016.4825] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 01/15/2016] [Indexed: 11/06/2022] Open
Abstract
Thrombosis and hemostasis take place in flowing blood, which generates shear forces. The effect of different shear rates, particularly pathological forces, on platelet thrombus formation remains to be fully elucidated. The present study observed the morphological characteristics and hierarchical structure of thrombi on the collagen surface at a wide range of wall shear rates (WSRs) and examined the underlying mechanisms. Calcein AM‑labeled whole blood was perfused over a collagen‑coated surface at different shear rates set by a Bioflux 200 microfluidic device and the thrombi formed were assessed for area coverage, the height and the hierarchical structure defined by the extent of platelet activation and packing density. The factors that affect thrombus formation were also investigated. Platelet thrombus formation varied under different WSRs, for example, dispersed platelet adhesion mixed with erythrocytes was observed at 125‑250 s(‑1), extensive and thin platelet thrombi were observed at 500‑1,500 s(‑1), and sporadic, thick thrombi were observed at pathological WSRs of 2,500‑5,000 s(‑1), which showed a tendency to be shed. With increasing WSRs, the height of the thrombi showed an increasing linear trend, whereas the total fluorescence intensity and area of the thrombi exhibited a parabolic curve‑like change, with a turning point at a WSR of 2,500 s(‑1). The number of thrombi, the average fluorescence intensity and the area per thrombus showed similar trends, with an initial upwards incline followed by a decline. The thrombi formed at higher WSRs had a thicker shell, which led to a more densely packed core. Platelet thrombus formation under shear‑flow was regulated by the adhesive strength, which was mediated by receptor‑ligand interaction, the platelet deposition induced by shear rates and the detachment by the dynamic force of flow. This resulted in a balance between thrombus attachment, including adhesion and aggregation, and detachment. Collectively, compared with physiological low WSRs, pathological high WSRs caused thicker and more easily shed thrombi with more condensed cores, which was regulated by an attachment‑detachment balance. These results provide novel insights into the properties of thrombus formation on collagen at different WSRs, and offers possible explanations for certain clinical physiopathological phenomena, including physical hemostasis and pathological thrombosis.
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Affiliation(s)
- Xiaofeng Shi
- Department of Hematology, Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, Collaborative Innovation Center of Hematology, Sino‑French Research Center for Life Sciences and Genomics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, P.R. China
| | - Jichun Yang
- Department of Hematology, Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, Collaborative Innovation Center of Hematology, Sino‑French Research Center for Life Sciences and Genomics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, P.R. China
| | - Jiansong Huang
- Department of Hematology, Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, Collaborative Innovation Center of Hematology, Sino‑French Research Center for Life Sciences and Genomics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, P.R. China
| | - Zhangbiao Long
- Department of Hematology, Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, Collaborative Innovation Center of Hematology, Sino‑French Research Center for Life Sciences and Genomics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, P.R. China
| | - Zheng Ruan
- Department of Hematology, Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, Collaborative Innovation Center of Hematology, Sino‑French Research Center for Life Sciences and Genomics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, P.R. China
| | - Bing Xiao
- Department of Hematology, Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, Collaborative Innovation Center of Hematology, Sino‑French Research Center for Life Sciences and Genomics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, P.R. China
| | - Xiaodong Xi
- Department of Hematology, Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, Collaborative Innovation Center of Hematology, Sino‑French Research Center for Life Sciences and Genomics, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, P.R. China
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190
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Wu Z, Boersema GSA, Taha D, Fine I, Menon A, Kleinrensink GJ, Jeekel J, Lange JF. Postoperative Hemodynamic Index Measurement With Miniaturized Dynamic Light Scattering Predicts Colorectal Anastomotic Healing. Surg Innov 2015; 23:115-23. [PMID: 26603692 DOI: 10.1177/1553350615618286] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Perioperative bowel perfusion (local hemodynamic index [LHI]) was measured with a miniaturized dynamic light scattering (mDLS) device, aiming to determine whether anastomotic perfusion correlates with the anastomotic healing process and whether LHI measurement assists in the detection of anastomotic leakage (AL) in colorectal surgery. METHODS A partial colectomy was performed in 21 male Wistar rats. Colonic and anastomotic LHIs were recorded during operation. On postoperative day (POD) 3, the rats were examined for AL manifestations. Anastomotic LHI was recorded before determining the anastomotic bursting pressure (ABP). The postoperative LHI measurements were repeated in 15 other rats with experimental colitis. Clinical manifestations and anastomotic LHI were also determined on POD3. Diagnostic value of LHI measurement was analyzed with the combined data from both experiments. RESULTS Intraoperative LHI measurement showed no correlation with the ABP on POD3. Postoperative anastomotic LHI on POD3 was significantly correlated with ABP in the normal rats (R(2) = 0.52; P < .001) and in the rats with colitis (R(2) = 0.63; P = .0012). Anastomotic LHI on POD3 had high accuracy for identifying ABP <50 mm Hg (Area under the curve = 0.86; standard error = 0.065; P < .001). A cutoff point of 1236 yielded a sensitivity of 100% and a specificity of 65%. On POD3, rats with LHIs <1236 had significantly higher dehiscence rates (40% vs 0%), more weight loss, higher abscess severity, and lower ABPs (P < .05); worse anastomotic inflammation and collagen deposition were also found in the histological examination. CONCLUSION Our data suggest that postoperative evaluation of anastomotic microcirculation with the mDLS device assists in the detection of AL in colorectal surgery.
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Affiliation(s)
- Zhouqiao Wu
- Erasmus University Medical Center, Rotterdam, Netherlands Peking University Cancer Hospital and Institute, Beijing, China
| | | | - Diman Taha
- Erasmus University Medical Center, Rotterdam, Netherlands
| | | | - Anand Menon
- Academic Colorectal Center, Havenziekenhuis, Rotterdam, Netherlands
| | | | | | - Johan F Lange
- Erasmus University Medical Center, Rotterdam, Netherlands
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191
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Sheriff J, Tran PL, Hutchinson M, DeCook T, Slepian MJ, Bluestein D, Jesty J. Repetitive Hypershear Activates and Sensitizes Platelets in a Dose-Dependent Manner. Artif Organs 2015; 40:586-95. [PMID: 26527361 DOI: 10.1111/aor.12602] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Implantation of mechanical circulatory support (MCS) devices-ventricular assist devices and the total artificial heart-has emerged as a vital therapy for advanced and end-stage heart failure. Unfortunately, MCS patients face the requirement of life-long antiplatelet and anticoagulant therapy to combat thrombotic complications resulting from the dynamic and supraphysiologic shear stress conditions associated with such devices, whose effect on platelet activation is poorly understood. We developed a syringe-capillary viscometer-the "platelet hammer"-that repeatedly exposed platelets to average shear stresses up to 1000 dyne/cm(2) for as short as 25 ms. Platelet activation state was measured using a modified prothrombinase assay, with morphological changes analyzed using scanning electron microscopy. We observed an increase in platelet activation state and post-high shear platelet activation rate, or sensitization, with an increase in stress accumulation (SA), the product of shear stress and exposure time. A significant increase in platelet activation state was observed beyond an SA of 1500 dyne-s/cm(2) , with a marked increase in pseudopod length visible beyond an SA of 1000 dyne-s/cm(2) . Utility of the platelet hammer extends to studies of other shear-dependent pathologies, and may assist development of approaches to enhance the safety and effectiveness of MCS devices and objective antithrombotic pharmacotherapy management.
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Affiliation(s)
- Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Phat L Tran
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA
| | - Marcus Hutchinson
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA
| | - Tracy DeCook
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA
| | - Marvin J Slepian
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA.,Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA.,Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, AZ, USA
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Jolyon Jesty
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
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192
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Panteleev MA, Dashkevich NM, Ataullakhanov FI. Hemostasis and thrombosis beyond biochemistry: roles of geometry, flow and diffusion. Thromb Res 2015; 136:699-711. [DOI: 10.1016/j.thromres.2015.07.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 07/22/2015] [Accepted: 07/26/2015] [Indexed: 11/16/2022]
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193
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Erratum to: Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions. Cardiovasc Eng Technol 2015; 6:577-89. [DOI: 10.1007/s13239-015-0243-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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194
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A reduced-dimensional model for near-wall transport in cardiovascular flows. Biomech Model Mechanobiol 2015; 15:713-22. [PMID: 26298313 DOI: 10.1007/s10237-015-0719-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/14/2015] [Indexed: 10/23/2022]
Abstract
Near-wall mass transport plays an important role in many cardiovascular processes, including the initiation of atherosclerosis, endothelial cell vasoregulation, and thrombogenesis. These problems are characterized by large Péclet and Schmidt numbers as well as a wide range of spatial and temporal scales, all of which impose computational difficulties. In this work, we develop an analytical relationship between the flow field and near-wall mass transport for high-Schmidt-number flows. This allows for the development of a wall-shear-stress-driven transport equation that lies on a codimension-one vessel-wall surface, significantly reducing computational cost in solving the transport problem. Separate versions of this equation are developed for the reaction-rate-limited and transport-limited cases, and numerical results in an idealized abdominal aortic aneurysm are compared to those obtained by solving the full transport equations over the entire domain. The reaction-rate-limited model matches the expected results well. The transport-limited model is accurate in the developed flow regions, but overpredicts wall flux at entry regions and reattachment points in the flow.
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195
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Clopidogrel response variability is associated with endothelial dysfunction in coronary artery disease patients receiving dual antiplatelet therapy. Atherosclerosis 2015; 242:102-8. [PMID: 26188531 DOI: 10.1016/j.atherosclerosis.2015.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Revised: 07/03/2015] [Accepted: 07/03/2015] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Dual antiplatelet therapy with aspirin and a platelet P2Y12 ADP receptor antagonist is the cornerstone of treatment following percutaneous coronary intervention (PCI). Several clinical and genetic factors can cause suboptimal clopidogrel response. We examined the impact of endothelial dysfunction on clopidogrel response variability in subjects with stable coronary artery disease (CAD) after PCI. METHODS We consecutively enrolled 198 patients with stable CAD one month after successful PCI. All patients were receiving dual antiplatelet therapy (clopidogrel 75 mg and aspirin 100 mg/day). Platelet reactivity was measured by VerifyNow P2Y12 assay (Accumetrics, San Diego, CA). VerifyNow reports its results in P2Y12 reaction units (PRU) and the diagnostic cut-off value is 230. Endothelial function was evaluated by flow mediated dilation (FMD). RESULTS Patients with high on treatment platelet reactivity (32% of the study population), compared to subjects with low on treatment platelet reactivity, presented decreased FMD values (4.35 ± 2.22% vs. 5.74 ± 3.29%, p = 0.01). Moreover, an inverse association between endothelial function measurement and platelet reactivity (r = -0.24, p = 0.001) was found. Importantly, multivariate analysis after adjustment for age, gender and confounders revealed by the univariate analysis (left ventricle ejection fraction, body mass index, diabetes, dyslipidemia, coronary lesion number) showed that for every decrease in FMD by 1% there is an anticipated increased in the odds of patients to have HPR by 1.66 (95% CI 1.03-2.57, p = 0.037). CONCLUSIONS Endothelial dysfunction is associated with clopidogrel response variability in patients after PCI receiving dual antiplatelet therapy. These findings shed some light on the mechanisms affecting individual platelet response to antiplatelet therapy and may explain the non-straight forward association between clopidogrel dose, platelet inhibition and cardiovascular outcome.
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196
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Wang CW, Perez MJ, Helmke BP, Viola F, Lawrence MB. Integration of acoustic radiation force and optical imaging for blood plasma clot stiffness measurement. PLoS One 2015; 10:e0128799. [PMID: 26042775 PMCID: PMC4456080 DOI: 10.1371/journal.pone.0128799] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 04/30/2015] [Indexed: 01/22/2023] Open
Abstract
Despite the life-preserving function blood clotting serves in the body, inadequate or excessive blood clot stiffness has been associated with life-threatening diseases such as stroke, hemorrhage, and heart attack. The relationship between blood clot stiffness and vascular diseases underscores the importance of quantifying the magnitude and kinetics of blood's transformation from a fluid to a viscoelastic solid. To measure blood plasma clot stiffness, we have developed a method that uses ultrasound acoustic radiation force (ARF) to induce micron-scaled displacements (1-500 μm) on microbeads suspended in blood plasma. The displacements were detected by optical microscopy and took place within a micro-liter sized clot region formed within a larger volume (2 mL sample) to minimize container surface effects. Modulation of the ultrasound generated acoustic radiation force allowed stiffness measurements to be made in blood plasma from before its gel point to the stage where it was a fully developed viscoelastic solid. A 0.5 wt % agarose hydrogel was 9.8-fold stiffer than the plasma (platelet-rich) clot at 1 h post-kaolin stimulus. The acoustic radiation force microbead method was sensitive to the presence of platelets and strength of coagulation stimulus. Platelet depletion reduced clot stiffness 6.9 fold relative to platelet rich plasma. The sensitivity of acoustic radiation force based stiffness assessment may allow for studying platelet regulation of both incipient and mature clot mechanical properties.
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Affiliation(s)
- Caroline W. Wang
- Department of Biomedical Engineering, School of Engineering and Applied Science and School of Medicine, University of Virginia Health System, Charlottesville, Virginia, United States of America
| | - Matthew J. Perez
- Department of Biomedical Engineering, School of Engineering and Applied Science and School of Medicine, University of Virginia Health System, Charlottesville, Virginia, United States of America
| | - Brian P. Helmke
- Department of Biomedical Engineering, School of Engineering and Applied Science and School of Medicine, University of Virginia Health System, Charlottesville, Virginia, United States of America
| | - Francesco Viola
- HemoSonics, LLC, Charlottesville, Virginia, United States of America
| | - Michael B. Lawrence
- Department of Biomedical Engineering, School of Engineering and Applied Science and School of Medicine, University of Virginia Health System, Charlottesville, Virginia, United States of America
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197
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Thorel J, Civade E, Quintyn JC, Cestac P, Montastruc JL, Bagheri H. Ischaemic stroke after exposure to aflibercept: interaction with vitamin K antagonist and/or direct pharmacodynamic effect? J Clin Pharm Ther 2015; 40:477-9. [PMID: 25930164 DOI: 10.1111/jcpt.12278] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/24/2015] [Indexed: 01/06/2023]
Abstract
WHAT IS KNOWN AND OBJECTIVE Vascular endothelial growth factor (VEGF) proteins are involved in the regulation of vascular endothelium, and their inhibition led to the development of a number of drugs used for malignancies or exudative neo-vascular age-related macular degeneration (AMD). CASE SUMMARY We report a case of ischemic stroke in an 87-year-old woman having received intravitreal aflibercept, a new anti-VEGF for AMD. She had been treated with ranibizumab since 2007. In 2013, ranibizumab was replaced with aflibercept, followed by a decrease in the International Normalized Ratio, complicated by a stroke a few days later. The rechallenge was positive. WHAT IS NEW AND CONCLUSION A potential time-dependent interaction between aflibercept and VKA antagonist and/or a direct effect of aflibercept may have contributed to the occurrence of the ischaemic stroke. Currently available data suggest some pharmacokinetic and pharmacodynamic effects of aflibercept by explaining its pro-thrombotic profile.
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Affiliation(s)
- J Thorel
- Department of Pharmacy, Toulouse University Hospital, Toulouse, France
| | - E Civade
- Department of Pharmacy, Toulouse University Hospital, Toulouse, France
| | - J C Quintyn
- Department of Ophthalmology, Toulouse University Hospital, Toulouse, France
| | - P Cestac
- Department of Pharmacy, Toulouse University Hospital, Toulouse, France.,Faculty of Pharmaceutical Sciences, Paul Sabatier University, Toulouse, France
| | - J-L Montastruc
- Service de Pharmacologie Médicale et Clinique, Centre Midi-Pyrénées de PharmacoVigilance, de Pharmacoépidémiologie et d'Informations sur le Médicament, CHU de Toulouse, Université de Toulouse, INSERM U1027, Faculté de Médecine, Toulouse, France
| | - H Bagheri
- Service de Pharmacologie Médicale et Clinique, Centre Midi-Pyrénées de PharmacoVigilance, de Pharmacoépidémiologie et d'Informations sur le Médicament, CHU de Toulouse, Université de Toulouse, INSERM U1027, Faculté de Médecine, Toulouse, France
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198
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The level of red cell distribution width cannot identify deep vein thrombosis in patients undergoing total joint arthroplasty. Blood Coagul Fibrinolysis 2015; 26:298-301. [DOI: 10.1097/mbc.0000000000000239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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199
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Harris DG, Benipal PK, Cheng X, Burdorf L, Azimzadeh AM, Pierson RN. Four-dimensional characterization of thrombosis in a live-cell, shear-flow assay: development and application to xenotransplantation. PLoS One 2015; 10:e0123015. [PMID: 25830912 PMCID: PMC4382176 DOI: 10.1371/journal.pone.0123015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 02/26/2015] [Indexed: 02/01/2023] Open
Abstract
Background Porcine xenografts are a promising source of scarce transplantable organs, but stimulate intense thrombosis of human blood despite targeted genetic and pharmacologic interventions. Current experimental models do not enable study of the blood/endothelial interface to investigate adhesive interactions and thrombosis at the cellular level under physiologic conditions. The purpose of this study was to develop and validate a live-cell, shear-flow based thrombosis assay relevant to general thrombosis research, and demonstrate its potential in xenotransplantation applications. Methodology/Principal Findings Confluent wild-type (WT, n = 48) and Gal transferase knock-out (GalTKO, which resist hyperacute rejection; n = 11) porcine endothelia were cultured in microfluidic channels. To mimic microcirculatory flow, channels were perfused at 5 dynes/cm2 and 37°C with human blood stained to fluorescently label platelets. Serial fluorescent imaging visualized percent surface area coverage (SA, for adhesion of labeled cells) and total fluorescence (a metric of clot volume). Aggregation was calculated by the fluorescence/SA ratio (FR). WT endothelia stimulated diffuse platelet adhesion (SA 65 ± 2%) and aggregation (FR 120 ± 1 a.u.), indicating high-grade thrombosis consistent with the rapid platelet activation and consumption seen in whole-organ lung xenotransplantation models. Experiments with antibody blockade of platelet aggregation, and perfusion of syngeneic and allo-incompatible endothelium was used to verify the biologic specificity and validity of the assay. Finally, with GalTKO endothelia thrombus volume decreased by 60%, due primarily to a 58% reduction in adhesion (P < 0.0001 each); importantly, aggregation was only marginally affected (11% reduction, P < 0.0001). Conclusions/Significance This novel, high-throughput assay enabled dynamic modeling of whole-blood thrombosis on intact endothelium under physiologic conditions, and allowed mechanistic characterization of endothelial and platelet interactions. Applied to xenogeneic thrombosis, it enables future studies regarding the effect of modifying the porcine genotype on sheer-stress-dependent events that characterize xenograft injury. This in-vitro platform is likely to prove broadly useful to study thrombosis and endothelial interactions under dynamic physiologic conditions.
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Affiliation(s)
- Donald G Harris
- Division of General Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America; Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Prabhjot K Benipal
- Division of Cardiac Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Xiangfei Cheng
- Division of Cardiac Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Lars Burdorf
- Division of Cardiac Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Agnes M Azimzadeh
- Division of Cardiac Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Richard N Pierson
- Division of Cardiac Surgery, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States of America; Surgical Care Clinical Center, VA Maryland Health Care System, Baltimore, Maryland, United States of America
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200
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Andersson M, Lantz J, Ebbers T, Karlsson M. Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions. Cardiovasc Eng Technol 2015; 6:281-93. [PMID: 26577361 DOI: 10.1007/s13239-015-0218-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 02/13/2015] [Indexed: 01/01/2023]
Abstract
Turbulence and flow eccentricity can be measured by magnetic resonance imaging (MRI) and may play an important role in the pathogenesis of numerous cardiovascular diseases. In the present study, we propose quantitative techniques to assess turbulent kinetic energy (TKE) and flow eccentricity that could assist in the evaluation and treatment of stenotic severities. These hemodynamic parameters were studied in a pre-treated aortic coarctation (CoA) and after several virtual interventions using computational fluid dynamics (CFD), to demonstrate the effect of different dilatation options on the flow field. Patient-specific geometry and flow conditions were derived from MRI data. The unsteady pulsatile flow was resolved by large eddy simulation including non-Newtonian blood rheology. Results showed an inverse asymptotic relationship between the total amount of TKE and degree of dilatation of the stenosis, where turbulent flow proximal the constriction limits the possible improvement by treating the CoA alone. Spatiotemporal maps of TKE and flow eccentricity could be linked to the characteristics of the jet, where improved flow conditions were favored by an eccentric dilatation of the CoA. By including these flow markers into a combined MRI-CFD intervention framework, CoA therapy has not only the possibility to produce predictions via simulation, but can also be validated pre- and immediate post treatment, as well as during follow-up studies.
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Affiliation(s)
- Magnus Andersson
- Department of Management and Engineering (IEI), Linköping University, 581 83, Linköping, Sweden. .,Swedish e-Science Research Center (SeRC), Stockholm, Sweden.
| | - Jonas Lantz
- Department of Science and Technology, Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
| | - Tino Ebbers
- Department of Science and Technology, Linköping University, Linköping, Sweden.,Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
| | - Matts Karlsson
- Department of Management and Engineering (IEI), Linköping University, 581 83, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
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