Blood Clot Contraction (Retraction) Is Impaired in Acute Ischemic Stroke

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4998-4998 ◽  
Author(s):  
Valerie Tutwiler ◽  
Alina Peshkova ◽  
Dina Khasanova ◽  
John W. Weisel ◽  
Rustem I. Litvinov
Keyword(s):  
Platelet Count ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Tissue Factor ◽  
Healthy Subjects ◽  
Blood Clot ◽  
Severe Stroke ◽  
Clot Contraction

Abstract Obstructive thrombi or thrombotic emboli of cerebral arteries are the pathogenic basis of ischemic stroke, which is a leading cause of death and disability worldwide. Blood clots undergo volume shrinkage due to the contractile forces that are generated by platelets and propagated through the clot volume due to platelet-fibrin interactions and elasticity of the fibrin network. This process is designed clot contraction (retraction) which remains one of the least studied steps of blood clotting. Importantly, this phenomenon has been shown to occur not only in vitro but also in in vivo thrombi. Clot contraction has been shown to be important in the volume reduction of otherwise obstructive thrombi and has the potential to reduce occlusion and restore blood flow past emboli or thrombi. Despite the potential medical significance of clot contraction, it has not been examined systemically in a clinical setting. This aim of this work was to examine the potential pathogenic role of clot contraction in ischemic stroke. Here we employed a novel automated method to quantify the time of initiation, extent and rate of clot contraction in vitro to compare clot contraction in the blood of healthy subjects with patients suffering a recent ischemic stroke (<6 hours from the onset of symptoms) who had not yet received any treatment with anticoagulants, antiplatelet drugs or thrombolytics.. Parameters of clot contraction were correlated with the severity and etiological types of stroke as well as with hematological, coagulation, and biochemical tests to examine the clinical significance of clot contraction. The main finding of this work is that clot contraction in blood from patients with acute ischemic stroke is reduced on average by ~60% (p<0.0001) when compared to that of healthy subjects. The reduction in clot contraction is correlated with a lower platelet count and platelet dysfunction, higher fibrinogen level, higher hematocrit, leukocytosis as well as other changes in the blood composition of patients with ischemic stroke that may alter the properties of the blood clot. We propose that these changes in the composition of the blood contribute to the impaired mechanism of clot contraction, which may exaggerate vessel occlusion and brain infarct. While stroke severity is determined mainly by the diameter and location of the obstructed cerebral artery, the ability of the thrombi to contract more or less may augment or ease the course of brain damage. Clinical correlations with respect to severity and stroke etiology indicate that reduced clot contraction has the potential to be a pathogenic factor in ischemic stroke. Paradoxically, the extent of clot contraction marginally improved in patients with a more severe stroke (NIHSS>15 vs. NIHSS<15, p<0.01), while it was still significantly reduced compared to healthy subjects. This finding can be presumably explained by the fact that in severe brain damage a massive amount of tissue factor is released into the systemic circulation, which can induce the activation of blood coagulation. We propose that this release of tissue factor results in a secondary wave of thrombin generation that causes patients with more severe stroke to have hyperactivity of platelets. In combination with a higher platelet count (p<0.01) this can enhance contraction of obstructive clots or thrombi, which may be a compensatory mechanism resulting in the recanalization of an otherwise occluded blood vessel. In support of this hypothetical scenario, it was also found that patients with atherothrombotic strokes have an increased extent of clot contraction compared to patients with cardioembolic stroke (p<0.05), and atherothrombotic patients are reported to have increased tissue factor as a consequence of atherosclerotic lesions. In summary, the clinical pathophysiological importance of clot contraction in a thrombotic state has been examined for the first time and the modulation of the ability of clots or thrombi to shrink in volume may be a novel and unappreciated mechanism that aggravates or alleviates the course and outcomes of thrombosis, such as ischemic stroke. The clinical importance of clot or thrombus remodeling in vivo as well as the diagnostic and prognostic value of this blood test for clot contraction needs further exploration. Disclosures Weisel: Bayer: Research Funding.

Abstract WP108: Novel Human Acute Ischemic Stroke Blood Clot Analogues for in-vitro Testing

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Seán Fitzgerald ◽  
Daying Dai ◽  
Andrew S Douglas ◽  
Oana M Mereuta ◽  
Thomas Caracena ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Red Blood Cells ◽  
Acute Ischemic Stroke ◽  
Human Blood ◽  
Whole Blood ◽  
Blood Cells ◽  
Blood Clot ◽  
Buffy Coat

Introduction: Previous studies have successfully created blood clot analogues for In-vitro testing using animal blood. Blood components vary greatly among species and thus, creating clot analogues with human blood is likely a more accurate representation of thrombi formed in the human vasculature. We present a novel method of creating clot analogues from human blood and platelets that mimic the process by which clots form In-vivo . Methods: Following IRB approval from Mayo Clinic, human whole blood and platelets donations were obtained from the Blood Transfusion service. The whole blood was centrifuged at 1,200RPM for 20 minutes to separate it into its constituents. Plasma was removed and the remaining Red Blood Cells and Buffy Coat were mixed together by inverting. A total of 12 clot analogues were created with varying concentrations of components; Red Blood cells/Buffy Coat, Plasma and Platelets. Thrombin was added first to stimulate platelets activation for a total of 5 mins whilst continuously mixing by inversion. The RBC/WBC mixture was added next followed by CaCl2. The mixture was then quickly drawn into a 3cc syringe and spun overnight at 20RPM at room temperature to mimic dynamic flow conditions. Macro-photographs were taken to display the variation in texture and color between different clot analogue types. The clots were then fixed in 10% neutral buffered formalin for 24 hours prior to being processed. Histopathological analysis was performed using Hematoxylin and Eosin (H&E) and Martius Scarlet Blue (MSB) staining to confirm clot composition. Results: Red Blood cell-rich, Fibrin-rich, Platelet-rich and mixed clot analogues that accurately mimic clots retrieved from Acute Ischemic Stroke Patients were created. The range of histopathological compositions of the clot analogues is similar to that of the clinical samples. Conclusions: The addition and activation of platelets is key to creating accurate clot analogues for In-vitro testing. Spinning the clots is important to prevent natural sedimentation and mimic the In-vivo situation.

scholarly journals Tissue factor and Toll-like receptor (TLR)4 in hyperglycaemia-hyperinsulinaemia

2015 ◽  
Vol 113 (04) ◽  
pp. 750-758 ◽  
Author(s):  
Anamika Singh ◽  
Guenther Boden ◽  
A. Koneti Rao
Keyword(s):  
Tissue Factor ◽  
Healthy Subjects ◽  
Toll Like Receptor ◽  
Elevated Plasma ◽  
Type 2 Dm ◽  
Type 1 Dm

SummaryDiabetes mellitus (DM) patients have an increased incidence of cardiovascular events. Blood tissue factor-procoagulant activity (TF-PCA), the initiating mechanism for blood coagulation, is elevated in DM. We have shown that hyperglycaemia (HG), hyperinsulinaemia (HI) and combined HG+HI (induced using 24-hour infusion clamps) increases TF-PCA in healthy and type 2 DM (T2DM) subjects, but not in type 1 DM (T1DM) subjects. The mechanisms for this are unknown. DM patients have elevated plasma lipopolysaccharide (LPS), a toll-like receptor (TLR) 4 ligand. We postulated that TLR4 plays a role in modulating TF levels. We studied the effect of HG+HI on TLR4 and TF-PCA in vivo during 24-hour HG+HI infusion clamps in healthy subjects, and T1DM and T2DM subjects, and in vitro in blood. In vivo, in healthy subjects, 24-hour HG + HI infusion increased TLR4 six-fold, which correlated with TF-PCA (r=0.91, p<0.0001). T2DM patients showed smaller increases in both. In T1DM subjects, TLR4 declined (50%, p<0.05) and correlated with TF-PCA (r=0.55; p<0.05). In vitro, HG (200 mg/dl added glucose) and HI (1-100 nM added insulin) increased TF-PCA in healthy subjects (˜2-fold, 2-4 hours). Insulin inhibited by ~30% LPSinduced increase in TF-PCA and high glucose reversed it. TLR4 levels paralleled TF-PCA (r=0.71, p<0.0001); HG and HI increased TLR4 and insulin inhibited LPS-induced TLR4 increase. This is first evidence that even in healthy subjects, HG of short duration increases TLR4 and TFPCA, key players in inflammation and thrombosis. TLR4-TF interplay is strikingly different in non-diabetic, T1DM and T2DM subjects.

In-Vitro Clot Modeling for the Preclinical Assessment of Mechanical Thrombectomy in Acute Ischemic Stroke

2010 ◽  
Author(s):  
Juyu Chueh ◽  
Christine F. Silva ◽  
Ajay K. Wakhloo ◽  
Matthew J. Gounis
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Clinical Outcomes ◽  
Mechanical Thrombectomy ◽  
Compression Behavior ◽  
Endovascular Recanalization

Mechanical thrombectomy devices, such as retrievers or aspiration catheters, have recently received approval from the FDA for the treatment of acute ischemic stroke. There is growing interest in endovascular recanalization procedures due to mounting evidence of favorable clinical outcomes. Several attempts have been made to establish dedicated clot models for in-vitro or in-vivo simulation of thromboembolism [1,2]. However, little is known about the mechanical and structural similarities between experimental clots and human sources of emboli that cause stroke. The goal of this study is to compare the structure and compression behavior of the possible sources of the cerebral emboli extracted from patients and model clots produced in-vitro using human, porcine and bovine donors.

Platelets in patients with acute ischemic stroke are exhausted and refractory to thrombin, due to cleavage of the seven-transmembrane thrombin receptor (PAR-1)

2004 ◽  
Vol 91 (02) ◽  
pp. 334-344 ◽  
Author(s):  
Kerstin Jurk ◽  
Uli-Rüdiger Jahn ◽  
Hugo Van Aken ◽  
Carsten Schriek ◽  
Dirk Droste ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Platelet Activation ◽  
Surface Expression ◽  
Thrombin Receptor ◽  
Acute Cerebral Ischemia ◽  
High Concentrations

SummaryPlatelet activation is involved in the pathogenesis of cerebrovascular ischemia, but the major agonist involved has yet to be identified. To investigate the role of thrombin in platelet activation in patients with acute ischemic stroke, and while thrombin is the most likely candidate for activation of the thrombin receptor PAR-1 in vivo, we assessed its cleavage and internalization using the antibodies SPAN12, binding to uncleaved PAR-1, and WEDE15, recognizing cleaved and uncleaved, but not internalized PAR-1. In contrast to healthy age-matched controls, platelets from stroke patients exhibited significant cleavage and internalization of PAR-1 (P<0.001) and failed to respond to thrombin in vitro. Enhanced surface expression of CD62P, CD63, TSP-1 and less mepacrine uptake showed platelet degranulation during stroke. Platelets from patients with acute cerebral ischemia are exhausted and desensitized to thrombin through cleavage of PAR-1, indicating that high concentrations of thrombin occur with acute cerebrovascular ischemic events in vivo.

scholarly journals Novel Human Acute Ischemic Stroke Blood Clot Analogs for In Vitro Thrombectomy Testing

2021 ◽  
Author(s):  
S.T. Fitzgerald ◽  
Y. Liu ◽  
D. Dai ◽  
O.M. Mereuta ◽  
M. Abbasi ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Blood Clot

Mechanical behavior of in vitro blood clots and the implications for acute ischemic stroke treatment

2019 ◽  
Vol 12 (9) ◽  
pp. 853-857 ◽  
Author(s):  
Sarah Johnson ◽  
Juyu Chueh ◽  
Matthew J Gounis ◽  
Ray McCarthy ◽  
J Patrick McGarry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ischemic Stroke ◽  
Mechanical Behavior ◽  
Acute Ischemic Stroke ◽  
Blood Clot ◽  
Volume Percentage ◽  
Stroke Treatment ◽  
Significant Difference ◽  
Stent Retrievers

BackgroundClot mechanical properties are influenced by composition and the arrangement of components within the clot. This work investigates the effects of platelet-driven contraction on blood clot microstructure and mechanical behavior, and provides insight into some implications for mechanical thrombectomy.MethodsPlatelet-contracted clot analogues (PCCs) and non-contracted clot analogues (NCCs) were prepared from blood mixtures of various hematocrits (%H), that is, the volume percentage of red blood cells (RBCs) in the mixture. Mechanical testing was performed to compare the behavior of the analogues with previously tested human thromboemboli. Scanning electron microscopy and histology investigated the clot microstructure and composition. The association between clot properties and their behavior during mechanical behavior was also investigated.ResultsOverall, PCCs were found to be stiffer than NCCs, across all hematocrits. PCCs with a low %H resisted complete ingestion via contact aspiration alone or complete retrieval with stent-retrievers. PCCs with a higher %H and all NCCs were fully retrievable, although the likelihood of fragmentation was increased in clots with a greater %H. Histologically, there was little difference in the RBC and fibrin content between PCCs and NCCs with the same %H. However, the microstructure of the two groups differed significantly.ConclusionA selection of repeatable clot analogues with a range of mechanical properties have been developed for in vitro modeling of acute ischemic stroke. Platelet contraction significantly affects clot volume and microstructure, and in turn clot stiffness. The significant difference in mechanical properties and microstructure, but without an appreciable difference in histology, implies that histological studies of explanted human clots alone may not prove to be predictive of the mechanical behavior of the clots in thrombectomy.

Predictive value of the ankle brachial index in patients with acute ischemic stroke

VASA ◽  
2014 ◽  
Vol 43 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Konstantinos Tziomalos ◽  
Vasilios Giampatzis ◽  
Stella Bouziana ◽  
Athinodoros Pavlidis ◽  
Marianna Spanou ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Hospital Mortality ◽  
Acute Ischemic Stroke ◽  
Ankle Brachial Index ◽  
Arterial Disease ◽  
National Institutes Of Health ◽  
Limited Data ◽  
Severe Stroke ◽  
Hospital Outcome ◽  
Peripheral Arterial

Background: Peripheral arterial disease (PAD) is frequently present in patients with acute ischemic stroke. However, there are limited data regarding the association between ankle brachial index (ABI) ≤ 0.90 (which is diagnostic of PAD) or > 1.40 (suggesting calcified arteries) and the severity of stroke and in-hospital outcome in this population. We aimed to evaluate these associations in patients with acute ischemic stroke. Patients and methods: We prospectively studied 342 consecutive patients admitted for acute ischemic stroke (37.4 % males, mean age 78.8 ± 6.4 years). The severity of stroke was assessed with the National Institutes of Health Stroke Scale (NIHSS)and the modified Rankin scale (mRS) at admission. The outcome was assessed with the mRS and dependency (mRS 2 - 5) at discharge and in-hospital mortality. Results: An ABI ≤ 0.90 was present in 24.6 % of the patients whereas 68.1 % had ABI 0.91 - 1.40 and 7.3 % had ABI > 1.40. At admission, the NIHSS score did not differ between the 3 groups (10.4 ± 10.6, 8.3 ± 9.3 and 9.3 ± 9.4, respectively). The mRS score was also comparable in the 3 groups (3.6 ± 1.7, 3.1 ± 1.8 and 3.5 ± 2.3, respectively). At discharge, the mRS score did not differ between the 3 groups (2.9 ± 2.2, 2.3 ± 2.1 and 2.7 ± 2.5, respectively) and dependency rates were also comparable (59.5, 47.6 and 53.3 %, respectively). In-hospital mortality was almost two-times higher in patients with ABI ≤ 0.90 than in patients with ABI 0.91 - 1.40 or > 1.40 but this difference was not significant (10.9, 6.6 and 6.3 %, respectively). Conclusions: An ABI ≤ 0.90 or > 1.40 does not appear to be associated with more severe stroke or worse in-hospital outcome in patients with acute ischemic stroke.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

Effect of Depolymerized Holothurian Glycosaminoglycan (DHG) on Tissue Factor Pathway Inhibitor: In Vitro and In Vivo Studies

1997 ◽  
Vol 78 (02) ◽  
pp. 864-870 ◽  
Author(s):  
Hideki Nagase ◽  
Kei-ichi Enjyoji ◽  
Yu-ichi Kamikubo ◽  
Keiko T Kitazato ◽  
Kenji Kitazato ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Tissue Factor Pathway Inhibitor ◽  
Factor Xa ◽  
Free Form ◽  
Initial Reaction ◽  
Extrinsic Pathway ◽  
Factor Xa Inhibition ◽  
Tissue Factor Pathway

SummaryDepolymerized holothurian glycosaminoglycan (DHG) is a glycosaminoglycan extracted from the sea cucumber Stichopus japonicusSelenka. In previous studies, we demonstrated that DHG has antithrombotic and anticoagulant activities that are distinguishable from those of heparin and dermatan sulfate. In the present study, we examined the effect of DHG on the tissue factor pathway inhibitor (TFPI), which inhibits the initial reaction of the tissue factor (TF)-mediated coagulation pathway. We first examined the effect of DHG on factor Xa inhibition by TFPI and the inhibition of TF-factor Vila by TFPI-factor Xa in in vitro experiments using human purified proteins. DHG increased the rate of factor Xa inhibition by TFPI, which was abolished either with a synthetic C-terminal peptide or with a synthetic K3 domain peptide of TFPI. In contrast, DHG reduced the rate of TF-factor Vila inhibition by TFPI-factor Xa. Therefore, the effect of DHG on in vitroactivity of TFPI appears to be contradictory. We then examined the effect of DHG on TFPI in cynomolgus monkeys and compared it with that of unfractionated heparin. DHG induced an increase in the circulating level of free-form TFPI in plasma about 20-fold when administered i.v. at 1 mg/kg. The prothrombin time (PT) in monkey plasma after DHG administration was longer than that estimated from the plasma concentrations of DHG. Therefore, free-form TFPI released by DHG seems to play an additive role in the anticoagulant mechanisms of DHG through the extrinsic pathway in vivo. From the results shown in the present work and in previous studies, we conclude that DHG shows anticoagulant activity at various stages of coagulation reactions, i.e., by inhibiting the initial reaction of the extrinsic pathway, by inhibiting the intrinsic Xase, and by inhibiting thrombin.

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