scholarly journals Blood clot contraction differentially modulates internal and external fibrinolysis

2019 ◽  
Vol 17 (2) ◽  
pp. 361-370 ◽  
Author(s):  
Valerie Tutwiler ◽  
Alina D. Peshkova ◽  
Giang Le Minh ◽  
Sergei Zaitsev ◽  
Rustem I. Litvinov ◽  
...  
Keyword(s):  
Blood Clot ◽  
Clot Contraction

scholarly journals Impaired contraction of blood clots precedes and predicts postoperative venous thromboembolism

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Natalia G. Evtugina ◽  
Alina D. Peshkova ◽  
Arseniy A. Pichugin ◽  
John W. Weisel ◽  
Rustem I. Litvinov
Keyword(s):  
Brain Tumors ◽  
Blood Clot ◽  
Surgical Interventions ◽  
Hematologic Tests ◽  
Vein Thrombosis ◽  
Blood Clots ◽  
Postoperative Thrombosis ◽  
Clot Contraction ◽  
Deep Vein ◽  
Contraction Assay

Abstract Deep vein thrombosis (DVT) is a common but unpredictable complication of surgical interventions. To reveal an association between the blood clot contraction (retraction) and the incidence of postoperative venous thrombosis, 78 patients with brain tumors that were operated on were studied, of which 23 (29%) were diagnosed with postoperative DVT. A clot contraction assay, along with other hemostatic and hematologic tests, was performed 1–3 days before the surgery and on the 1st day and 5–7th days after the surgery. On the 1st postoperative day, clot contraction was significantly suppressed in patients who subsequently developed DVT, compared to the patients without DVT. Importantly, this difference was observed at least 5 days before DVT had developed. The weakening of contraction on the 1st postoperative day was more pronounced in the DVT patients with malignant versus benign brain tumors, atherosclerosis, hypertension, as well as in patients receiving steroids before and during the operation. These results indicate that impaired clot contraction in the postoperative period is associated with imminent DVT, suggesting that it is a prothrombotic risk factor and promotional mechanism. The clot contraction assay has a predictive value in assessing the threat of postoperative thrombosis in patients with benign and malignant brain tumors.

Premorbid Hemostasis in Women with a History of Pregnancy Loss

2019 ◽  
Vol 119 (12) ◽  
pp. 1994-2004 ◽  
Author(s):  
Alina D. Peshkova ◽  
Svetlana I. Safiullina ◽  
Natalia G. Evtugina ◽  
Yelena S. Baras ◽  
Fazoil I. Ataullakhanov ◽  
...  
Keyword(s):  
Pregnancy Loss ◽  
Blood Clot ◽  
Significant Inhibition ◽  
Obstetric Complications ◽  
In Vitro Assays ◽  
History Of ◽  
Clot Contraction ◽  
Hemostatic Disorders ◽  
In Pregnancy

Abstract Background Congenital and acquired hemostatic disorders are among the pathogenic factors of pregnancy loss. Studying mechanistic relations between impaired hemostasis and fetal losses is important for the prognosis and prophylaxis of obstetric complications. Objective This article aims to establish latent hemostatic disorders in nonpregnant women as an important premorbid risk factor of pregnancy loss. Methods and Results Hemostasis was characterized using two relatively new in vitro assays, namely thrombodynamics (spatial clot growth) and kinetics of blood clot contraction, which together reflect the hemostatic or thrombotic potential. In addition, platelet functionality was assessed using flow cytometry. Our study included 50 women with a history of pregnancy loss and 30 parous women without previous obstetric complications. In patients with pregnancy loss, hypercoagulability was observed along with significant impairment of blood clot contraction associated with chronic platelet activation and dysfunction. Both hypercoagulability and defective clot contraction were significantly more pronounced in patients with a history of three or more miscarriages compared with patients with a history of one or two miscarriages. In addition, a significant inhibition of clot contraction was found in patients with miscarriage occurring after 10 weeks of gestation compared with those who lost a fetus earlier in pregnancy. Conclusion These results indicate that chronic hypercoagulability and impaired clot contraction constitute a premorbid status in patients with pregnancy loss. The data confirm a significant pathogenic role of hemostatic disorders in pregnancy loss and suggest the predictive value of thrombodynamics and blood clot contraction assays in evaluating the risk of pregnancy loss.

Effects of Platelets and Erythrocytes on the Dynamic Size and Mechanical Properties of Blood Clots during Contraction

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4225-4225
Author(s):  
Valerie Tutwiler ◽  
Rustem I. Litvinov ◽  
Tatiana Lebedeva ◽  
Fazoil I. Ataullakhanov ◽  
Douglas B. Cines ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Viscoelastic Properties ◽  
Blood Clot ◽  
Final Size ◽  
Fibrin Network ◽  
Blood Clots ◽  
Platelet Concentration ◽  
Clot Contraction ◽  
Contractile Forces ◽  
Kinetics Of

Abstract Clot contraction is a final step of blood clotting and plays a key role in hemostasis and restoring blood flow past obstructive thrombi. The volume shrinkage of clots is driven by the contractile forces generated by activated platelets and propagated by the platelet-attached viscoelastic fibrin fibers throughout the entire clot. We have recently shown that blood clot contraction results in the formation of compressed. tightly packed, polyhedral erythrocytes (polyhedrocytes) and in the redistribution of platelets and fibrin to the surface of the contracted clot as a result of the complex interplay between platelets, fibrin, and erythrocytes. This study further investigates the role of these major blood cells in the dynamic mechanical (or viscoelastic) properties of the clot and the kinetics of clot contraction. Platelet and erythrocyte levels were varied through the use of partially reconstituted blood. Samples of platelet-containing plasma with or without added erythrocytes were recalcified and activated with thrombin. The viscoelastic properties and the force of contraction of the resultant clot were determined using high precision rheology. The kinetics of contraction was analyzed using a Thromboimager (HemaCore, Moscow, Russia), which allows continuous tracking and quantitative characterization of dynamic clot size by sensing changes in the light scattering of the clot over time. As predicted, the rate and degree of clot contraction depended linearly on the platelet count over a broad range (R2=0.9881). Increased platelet concentration of greater than 500 k/μl resulted in a more than 30% increase (p<0.001) in the percentage of clot contraction at 30 minutes when compared to the lowest platelet concentration (<75 k/μl). There was a significant increase in the rate and a ~15% increase (p<0.001) in the percentage of clot contraction seen in samples with 250-300k/μl, however, and no difference in samples with 125-150k/μl when compared to the lowest platelet concentration. It was observed that increasing the hematocrit level also affected the degree of contraction with a 30% decrease (p<0.001) in the percentage of contraction seen as the erythrocyte level was increased to hematocrit >40% when compared to <10% hematocrit. There was a 10-15% decrease in the percentage of contraction seen at intermediate hematocrit levels (p<0.05). In addition to decreasing the degree of contraction, changing the cellular composition also affected the rate of contraction. Increasing the concentration of either erythrocytes or platelets resulted in a relative increase in the viscous (or plastic) properties when compared to elastic (or stiffness) properties of the clot (p<0.01), showing a complex dependence of the viscoelastic behavior of the contracting clot as a result of the addition of cells. The presence of erythrocytes resulted in a 63% increase (p<0.05) in the contractile forces that were generated by the platelet-fibrin network when compared to platelets alone. We interpret these results as a profound effect of erythrocytes on the course of clot contraction and on the final size and mechanical properties of contracted blood clots. These results reveal that the concentration of cellular components critically affects the ability of the platelet-fibrin network on the outside of the clot to generate forces needed to reduce the clot size and to compact the erythrocytes, resulting in the formation of a stiff, dense hemostatic plug with low permeability. Disclosures Ataullakhanov: HemaCore LLC: Employment, Membership on an entity's Board of Directors or advisory committees.

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.

CHANGES IN THE PARAMETERS OF THROMBODYNAMICS AND BLOOD CLOT CONTRACTION IN PATIENTS WITH RHEUMATOID ARTHRITIS

2020 ◽  
Vol 58 (3) ◽  
pp. 294-303
Author(s):  
A. D. Peshkova ◽  
T. A. Evdokimova ◽  
T. B. Sibgatullin ◽  
F. I. Ataullakhanov ◽  
R. I. Litvinov
Keyword(s):  
Rheumatoid Arthritis ◽  
Blood Clot ◽  
Clinical Manifestations ◽  
Control Group ◽  
Healthy Individuals ◽  
Plasma Clot ◽  
Autoimmune Pathology ◽  
Clot Contraction ◽  
Hemostatic Disorders

Autoimmune diseases, including rheumatoid arthritis (RA), are risk factors for thrombotic events. Understanding the pathogenetic role of hemostatic changes in RA can assist in developing measures for prevention, prognosis, early diagnosis, and treatment of immune thromboses. Objective: to investigate the state of platelet and plasma hemostasis in patients with RA, as compared to other laboratory parameters and clinical manifestations of the disease. Subjects and methods. Hemostasis was investigated using two relatively new laboratory tests: thrombodynamics and kinetics of blood clot contraction (BCC). Examinations were made in 60 patients with RA and in 50 apparently healthy individuals of the control group. Results and discussion. In patients with RA, the parameters of thrombodynamics and BCC were found to be significantly different from the normal values. According to thrombodynamics, there was an increase in plasma clot growth rate, size, and density, which indicates chronic hypercoagulation. The rate and completeness of BCC were substantially reduced due to platelet dysfunction in patients with RA compared to healthy individuals. The changes in the parameters of thrombodynamics and BCC correlated with the laboratory signs of systemic inflammation and depended on the radiographic stage of the disease. Conclusion. The results of this investigation confirm that hemostatic disorders are present in RA and indicate the informative value of thrombodynamics and BCC tests as indicators of a pre-thrombotic state, including autoimmune pathology.

scholarly journals Shape changes of erythrocytes during blood clot contraction and the structure of polyhedrocytes

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Valerie Tutwiler ◽  
Alexander R. Mukhitov ◽  
Alina D. Peshkova ◽  
Giang Le Minh ◽  
R. R. Khismatullin ◽  
...  
Keyword(s):  
Blood Clot ◽  
Clot Contraction ◽  
Shape Changes

scholarly journals Reduced Contraction of Blood Clots in Venous Thromboembolism Is a Potential Thrombogenic and Embologenic Mechanism

TH Open ◽  
2018 ◽  
Vol 02 (01) ◽  
pp. e104-e115 ◽  
Author(s):  
Alina Peshkova ◽  
Dmitry Malyasyov ◽  
Roman Bredikhin ◽  
Giang Le Minh ◽  
Izabella Andrianova ◽  
...  
Keyword(s):  
Venous Thromboembolism ◽  
Ex Vivo ◽  
Blood Clot ◽  
Chemical Activation ◽  
Healthy Controls ◽  
Activation Markers ◽  
Fold Reduction ◽  
Blood Clots ◽  
Clot Contraction

AbstractContraction (retraction) of the blood clot is a part of the clotting process driven by activated platelets attached to fibrin that can potentially modulate the obstructiveness and integrity of thrombi. The aim of this work was to reveal the pathogenic importance of contraction of clots and thrombi in venous thromboembolism (VTE). We investigated the kinetics of clot contraction in the blood of 55 patients with VTE. In addition, we studied the ultrastructure of ex vivo venous thrombi as well as the morphology and functionality of isolated platelets. Thrombi from VTE patients contained compressed polyhedral erythrocytes, a marker for clot contraction in vivo. The extent and rate of contraction were reduced by twofold in clots from the blood of VTE patients compared with healthy controls. The contraction of clots from the blood of patients with pulmonary embolism was significantly impaired compared with that of those with isolated venous thrombosis, suggesting that less compacted thrombi are prone to embolization. The reduced ability of clots to contract correlated with continuous platelet activation followed by their partial refractoriness. Morphologically, 75% of platelets from VTE patients were spontaneously activated (with filopodia) compared with only 21% from healthy controls. At the same time, platelets from VTE patients showed a 1.4-fold reduction in activation markers expressed in response to chemical activation when compared with healthy individuals. The results obtained suggest that the impaired contraction of thrombi is an underappreciated pathogenic mechanism in VTE that may regulate the obstructiveness and embologenicity of venous thrombi.

scholarly journals Effects of Hyperhomocysteinemia on the Platelet-Driven Contraction of Blood Clots

Metabolites ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 354
Author(s):  
Rustem I. Litvinov ◽  
Alina D. Peshkova ◽  
Giang Le Minh ◽  
Nail N. Khaertdinov ◽  
Natalia G. Evtugina ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Platelet Activation ◽  
Rat Model ◽  
Binding Capacity ◽  
Blood Clot ◽  
Fibrinogen Binding ◽  
Blood Clots ◽  
Clot Contraction ◽  
Dose Dependent

Hyperhomocysteinemia (HHcy) is associated with thrombosis, but the mechanistic links between them are not understood. We studied effects of homocysteine (Hcy) on clot contraction in vitro and in a rat model of HHcy. Incubation of blood with exogenous Hcy for 1 min enhanced clot contraction, while 15-min incubation led to a dose-dependent suppression of contraction. These effects were likely due to direct Hcy-induced platelet activation followed by exhaustion, as revealed by an increase in fibrinogen-binding capacity and P-selectin expression determined by flow cytometry. In the blood of rats with HHcy, clot contraction was enhanced at moderately elevated Hcy levels (10–50 μM), while at higher Hcy levels (>50 μM), the onset of clot contraction was delayed. HHcy was associated with thrombocytosis combined with a reduced erythrocyte count and hypofibrinogenemia. These data suggest that in HHcy, platelets get activated directly and indirectly, leading to enhanced clot contraction that is facilitated by the reduced content and resilience of fibrin and erythrocytes in the clot. The excessive platelet activation can lead to exhaustion and impaired contractility, which makes clots larger and more obstructive. In conclusion, HHcy modulates blood clot contraction, which may comprise an underappreciated pro- or antithrombotic mechanism.

scholarly journals Force-Independent Cleavage of Talin by Calpain Promotes Platelet-Mediated Fibrin Clot Contraction

2021 ◽  
Author(s):  
Karen P. Fong ◽  
Kathleen S. Molnar ◽  
Nicholas J. Agard ◽  
Rustem I Litvinov ◽  
Oleg V. Kim ◽  
...  
Keyword(s):  
Binding Sites ◽  
Blood Clot ◽  
Tensile Force ◽  
Structural Rearrangement ◽  
Fibrin Clot ◽  
Clot Retraction ◽  
Clot Contraction ◽  
Α Helix ◽  
Unstructured Regions

Blood clot contraction is driven by traction forces generated by the platelet cytoskeleton that are transmitted to fibrin fibers via the integrin αIIbβ3. Here we show that clot contraction is impaired by inhibitors of the platelet cytosolic protease calpain. We used subtiligase-mediated labeling of amino-termini and mass spectrometry to identify proteolytically-cleaved platelet proteins involved in clot contraction. Of 32 calpain-cleaved proteins after TRAP stimulation, fourteen were cytoskeletal, most prominently talin and vinculin. A complex of talin and vinculin constitutes a "mechanosensitive clutch" connecting integrins bound to the extracellular matrix to the actin cytoskeleton. Accordingly, we focused on talin and vinculin. Talin is composed of an N-terminal head domain and a C-terminal rod domain organized into a series of four- and five-helix bundles. The bundles contain 11 vinculin binding sites (VBS), each of which is an α-helix packed into a bundle interior and requiring a structural rearrangement to initiate vinculin binding. We detected 8 calpain-mediated cleavages in talin, 2 previously identified in unstructured regions and 6 in α-helical regions in proximity to a VBS. There is evidence in vitro that applying mechanical force across talin enables vinculin binding to the talin rod. However, we found that inhibiting platelet cytoskeletal contraction had no effect on talin cleavage, indicating that talin cleavage by calpain in platelets does not require cytoskeleton-generated tensile force. Thus, it is likely that calpain acts in the later stages of clot retraction through focal adhesion disassembly.

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