A three-dimensional phase-field model for multiscale modeling of thrombus biomechanics in blood vessels.
Zheng Xiaoning,Yazdani Alireza,Li He,Humphrey Jay D,Karniadakis George E
PLoS computational biology
Mechanical interactions between flowing and coagulated blood (thrombus) are crucial in dictating the deformation and remodeling of a thrombus after its formation in hemostasis. We propose a fully-Eulerian, three-dimensional, phase-field model of thrombus that is calibrated with existing in vitro experimental data. This phase-field model considers spatial variations in permeability and material properties within a single unified mathematical framework derived from an energy perspective, thereby allowing us to study effects of thrombus microstructure and properties on its deformation and possible release of emboli under different hemodynamic conditions. Moreover, we combine this proposed thrombus model with a particle-based model which simulates the initiation of the thrombus. The volume fraction of a thrombus obtained from the particle simulation is mapped to an input variable in the proposed phase-field thrombus model. The present work is thus the first computational study to integrate the initiation of a thrombus through platelet aggregation with its subsequent viscoelastic responses to various shear flows. This framework can be informed by clinical data and potentially be used to predict the risk of diverse thromboembolic events under physiological and pathological conditions.
Microbiota thrombus colonization may influence athero-thrombosis in hyperglycemic patients with ST segment elevation myocardialinfarction (STEMI). Marianella study.
Sardu Celestino,Consiglia Trotta Maria,Santella Biagio,D'Onofrio Nunzia,Barbieri Michelangela,Rizzo Maria Rosaria,Sasso Ferdinando Carlo,Scisciola Lucia,Turriziani Fabrizio,Torella Michele,Portoghese Michele,Loreni Francesco,Mureddu Simone,Lepore Maria Antonietta,Galdiero Massimiliano,Franci Gianluigi,Folliero Veronica,Petrillo Arianna,Boatti Lara,Minicucci Fabio,Mauro Ciro,Calabrò Paolo,Feo Marisa De,Balestrieri Maria Luisa,Ercolini Danilo,D'Amico Michele,Paolisso Giuseppe,Galdiero Marilena,Marfella Raffaele
Diabetes research and clinical practice
OBJECTIVES:We examined the association of the coronary thrombus microbiota and relative metabolites with major adverse cardiovascular events (MACE) in hyperglycemic patients with ST segment elevation myocardial infarction (STEMI). BACKGROUND:Hyperglycemia during STEMI may affect both development and progression of coronary thrombus via gut and thrombus microbiota modifications. METHODS:We undertook an observational cohort study of 146 first STEMI patients treated with primary percutaneous coronary intervention (PPCI) and thrombus-aspiration (TA). Patients were clustered, based on admission blood glucose levels, in hyperglycemic (≥140 mg/dl) and normoglycemic (<140 mg/dl). We analyzed gut and thrombus microbiota in all patients. Moreover, we assessed TMAO, CD40L and von Willebrand Factor (vWF) in coronary thrombi. Cox regressions were used for the association between Prevotellaspp. and TMAO terziles and MACE. MACE endpoint at 1 year included death, re-infarction, unstable angina. RESULTS:In fecal and thrombus samples, we observed a significantly different prevalence of both Prevotellaspp. and Alistipesspp. between patients with hyperglycemia (n = 56) and those with normal glucose levels (n = 90). The abundance of Prevotella increased in hyperglycemic vs normoglycemic patients whereas the contrary was observed for Alistipes. Interestingly, in coronary thrombus, the content of Prevotella was associated with admission blood glucose levels (p < 0.01), thrombus dimensions (p < 0.01), TMAO, CDL40 (p < 0.01) and vWF (p < 0.01) coronary thrombus contents. Multivariate Cox-analysis disclosed a reduced survival in patients with high levels of Prevotella and TMAO in coronary thrombus as compared to patients with low levels of Prevotella and TMAO, after 1-year follow up. CONCLUSIONS:Hyperglycemia during STEMI may increase coronary thrombus burden via gut and thrombus microbiota dysbiosis characterized by an increase of Prevotella and TMAO content in thrombi. CLINICAL TRIAL REGISTRATION:NCT03439592. September 30, 2016. Ethic Committee Vanvitelli University: 268/2016.
Predictive modelling of thrombus formation in diabetic retinal microaneurysms.
Li He,Sampani Konstantina,Zheng Xiaoning,Papageorgiou Dimitrios P,Yazdani Alireza,Bernabeu Miguel O,Karniadakis George E,Sun Jennifer K
Royal Society open science
Microaneurysms (MAs) are one of the earliest clinically visible signs of diabetic retinopathy (DR). Vision can be reduced at any stage of DR by MAs, which may enlarge, rupture and leak fluid into the neural retina. Recent advances in ophthalmic imaging techniques enable reconstruction of the geometries of MAs and quantification of the corresponding haemodynamic metrics, such as shear rate and wall shear stress, but there is lack of computational models that can predict thrombus formation in individual MAs. In this study, we couple a particle model to a continuum model to simulate the platelet aggregation in MAs with different shapes. Our simulation results show that under a physiologically relevant blood flow rate, thrombosis is more pronounced in saccular-shaped MAs than fusiform-shaped MAs, in agreement with recent clinical findings. Our model predictions of the size and shape of the thrombi in MAs are consistent with experimental observations, suggesting that our model is capable of predicting the formation of thrombus for newly detected MAs. This is the first quantitative study of thrombosis in MAs through simulating platelet aggregation, and our results suggest that computational models can be used to predict initiation and development of intraluminal thrombus in MAs as well as provide insights into their role in the pathophysiology of DR.
Neutrophils: back in the thrombosis spotlight.
Noubouossie Denis F,Reeves Brandi N,Strahl Brian D,Key Nigel S
Reactive and clonal neutrophil expansion has been associated with thrombosis, suggesting that neutrophils play a role in this process. However, although there is no doubt that activated monocytes trigger coagulation in a tissue factor-dependent manner, it remains uncertain whether stimulated neutrophils can also directly activate coagulation. After more than a decade of debate, it is now largely accepted that normal human neutrophils do not synthetize tissue factor, the initiator of the extrinsic pathway of coagulation. However, neutrophils may passively acquire tissue factor from monocytes. Recently, the contact system, which initiates coagulation via the intrinsic pathway, has been implicated in the pathogenesis of thrombosis. After the recent description of neutrophil extracellular trap (NET) release by activated neutrophils, some animal models of thrombosis have demonstrated that coagulation may be enhanced by direct NET-dependent activation of the contact system. However, there is currently no consensus on how to assess or quantify NETosis in vivo, and other experimental animal models have failed to demonstrate a role for neutrophils in thrombogenesis. Nevertheless, it is likely that NETs can serve to localize other circulating coagulation components and can also promote vessel occlusion independent of fibrin formation. This article provides a critical appraisal of the possible roles of neutrophils in thrombosis and highlights some existing knowledge gaps regarding the procoagulant activities of neutrophil-derived extracellular chromatin and its molecular components. A better understanding of these mechanisms could guide future approaches to prevent and/or treat thrombosis.
Disseminated intravascular coagulation.
Gando Satoshi,Levi Marcel,Toh Cheng-Hock
Nature reviews. Disease primers
Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by widespread intravascular activation of coagulation that can be caused by infectious insults (such as sepsis) and non-infectious insults (such as trauma). The main pathophysiological mechanisms of DIC are inflammatory cytokine-initiated activation of tissue factor-dependent coagulation, insufficient control of anticoagulant pathways and plasminogen activator inhibitor 1-mediated suppression of fibrinolysis. Together, these changes give rise to endothelial dysfunction and microvascular thrombosis, which can cause organ dysfunction and seriously affect patient prognosis. Recent observations have pointed to an important role for extracellular DNA and DNA-binding proteins, such as histones, in the pathogenesis of DIC. The International Society on Thrombosis and Haemostasis (ISTH) established a DIC diagnostic scoring system consisting of global haemostatic test parameters. This scoring system has now been well validated in diverse clinical settings. The theoretical cornerstone of DIC management is the specific and vigorous treatment of the underlying conditions, and DIC should be simultaneously managed to improve patient outcomes. The ISTH guidance for the treatment of DIC recommends treatment strategies that are based on current evidence. In this Primer, we provide an updated overview of the pathophysiology, diagnosis and management of DIC and discuss the future directions of basic and clinical research in this field.
The role of leukocytes in thrombosis.
Swystun Laura L,Liaw Patricia C
In recent years, the traditional view of the hemostatic system as being regulated by a coagulation factor cascade coupled with platelet activation has been increasingly challenged by new evidence that activation of the immune system strongly influences blood coagulation and pathological thrombus formation. Leukocytes can be induced to express tissue factor and release proinflammatory and procoagulant molecules such as granular enzymes, cytokines, and damage-associated molecular patterns. These mediators can influence all aspects of thrombus formation, including platelet activation and adhesion, and activation of the intrinsic and extrinsic coagulation pathways. Leukocyte-released procoagulant mediators increase systemic thrombogenicity, and leukocytes are actively recruited to the site of thrombus formation through interactions with platelets and endothelial cell adhesion molecules. Additionally, phagocytic leukocytes are involved in fibrinolysis and thrombus resolution, and can regulate clearance of platelets and coagulation factors. Dysregulated activation of leukocyte innate immune functions thus plays a role in pathological thrombus formation. Modulation of the interactions between leukocytes or leukocyte-derived procoagulant materials and the traditional hemostatic system is an attractive target for the development of novel antithrombotic strategies.
Coagulation factor XII in thrombosis and inflammation.
Maas Coen,Renné Thomas
Combinations of proinflammatory and procoagulant reactions are the unifying principle for a variety of disorders affecting the cardiovascular system. The factor XII-driven contact system starts coagulation and inflammatory mechanisms via the intrinsic pathway of coagulation and the bradykinin-producing kallikrein-kinin system, respectively. The biochemistry of the contact system in vitro is well understood; however, its in vivo functions are just beginning to emerge. Challenging the concept of the coagulation balance, targeting factor XII or its activator polyphosphate, provides protection from thromboembolic diseases without interfering with hemostasis. This suggests that the polyphosphate/factor XII axis contributes to thrombus formation while being dispensable for hemostatic processes. In contrast to deficiency in factor XII providing safe thromboprotection, excessive FXII activity is associated with the life-threatening inflammatory disorder hereditary angioedema. The current review summarizes recent findings of the polyphosphate/factor XII-driven contact system at the intersection of procoagulant and proinflammatory disease states. Elucidating the contact system offers the exciting opportunity to develop strategies for safe interference with both thrombotic and inflammatory disorders.