Abstract 35: Plasma Fibronectin is a Vital Supportive Factor in Hemostasis and a Unique Self-Limiting Regulator in Thrombosis

The role of plasma fibronectin (pFn) in thrombosis/hemostasis is controversial. We previously demonstrated that pFn supports thrombosis in pFn-/- mice. Interestingly, depletion of pFn in fibrinogen (Fg)/VWF-/- mice resulted in enhanced thrombus formation, revealing a functional switch of pFn in the absence of Fg/VWF. However, the mechanism controlling this switch is unknown. Furthermore, the hemostatic function of pFn is unclear. To address these questions, we established Fg/pFn-/- and VWF/pFn-/- mice in addition to triple deficient mice (Fg/VWF/pFn-/-, TKO). TKO mice had significantly higher mortality (23.1% vs. 9.1%) and longer tail bleeding time than their pFn+ Fg/VWF-/- littermates. Autopsy revealed severe subcutaneous or abdominal bleeding. pFn depletion in Fg-/- mice also increased mortality from 5.5% to 25.6% and prolonged bleeding times; the latter effect was reversed with pFn infusion. Using intravital microscopy, we found that pFn deposition at the site of injury preceded significant platelet accumulation, suggesting that pFn is an efficient and rapid hemostatic factor. Based on thromboelastography, fibrin clots from pFn+ mice were significantly stronger than those from pFn-/- mice. Consistent with this, inferior vena cava occlusion was significantly delayed in pFn-/- mice. Under confocal microscopy, fluorescently-labeled pFn was actively recruited into the fibrin network in mouse and human plasma. Under electron microscopy, physiological levels of pFn doubled the diameter of fibrin fibers, suggesting that pFn contributes to lateral aggregation of fibrin protofibrils. Interestingly, pFn enhances platelet aggregation when linked with fibrin and inhibits aggregation when fibrin is absent. pFn therefore gradually switches from supporting hemostasis to inhibiting thrombosis and vessel occlusion following the fibrin gradient that decreases farther from the injured endothelium. Our data established pFn as an important supportive factor in hemostasis and a unique self-limiting regulator of thrombosis, suggesting the therapeutic potential of pFn transfusion in controlling bleeding complications, particularly for those receiving antithrombotic therapy for heart attack and stroke.

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Chronically Elevated Interleukin-6 Disturbs the Coagulation Cascade in Mice

Blood ◽

10.1182/blood-2021-149628 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2065-2065

Author(s):

Tanja Knopp ◽

Jeremy Lagrange ◽

Rebecca Jung ◽

Johannes Wild ◽

Heidi Rossmann ◽

...

Keyword(s):

Board Of Directors ◽

Interleukin 6 ◽

Thrombus Formation ◽

Vena Cava ◽

Coagulation Cascade ◽

Bleeding Complications ◽

Thrombin Inhibitor ◽

Advisory Committees ◽

Hemostatic System

Abstract Introduction: Pro-inflammatory cytokines play an essential role as activators of the hemostatic system and in the regulation of physiological antithrombotic mechanisms. Interleukin-6 (IL-6) influences platelet production and platelet activation. It was associated with accelerated clotting and intravascular coagulation in tissue factor (TF)-driven murine thrombosis models. However, the precise role of myeloid cell-derived IL-6 on thrombosis formation and the hemostatic system is still unknown. Methods and Results: To better understand the role of IL-6 in thrombosis and the hemostatic system, we developed a new mouse strain with Cre-recombinase driven constitutive IL-6 expression specifically in myeloid cells (LysM-IL-6 OE, Control mice: IL-6 OE). LysM-IL-6 OE mice had a prolonged tail bleeding time and lacked venous thrombus formation induced by inferior vena cava (IVC) stenosis. There were no differences in D-Dimer levels in LysM-IL-6 OE mice neither on baseline level nor after IVC ligation. However, we found unstoppable post-operative bleedings in LysM-IL-6 OE. They showed a prolonged aPTT, a significantly increased INR and a prolonged thrombin converting time. The Factor V and IX expression were reduced, but von Willebrand factor, antithrombin and fibrinogen expression were up-regulated and could not explain the missing thrombus formation. We found significantly elevated erythrocyte sedimentation in line with erythrocytes aggregates, which seemed to be mediated by IL-6 and α2M. Most importantly, hepatic levels of thrombin inhibitor α2 macroglobulin (α2M) mRNA and protein were increased in LysM-IL-6 OE/+ mice compared to control mice. In parallel, Platelet erythrocyte interaction seemed to be essential in the development of the bleeding phenotype. Conclusions: These findings show the role of chronically elevated IL-6 in driving the accumulation of A2m on the surface of erythrocytes, thereby mediating a phenotype of increased bleeding complications. This work was supported by the DFG KA4035/1-1 and by the German Ministry for Education and Research (BMBF 01EO1503) Disclosures Lämmle: Takeda: Membership on an entity's Board of Directors or advisory committees; Ablynx: Membership on an entity's Board of Directors or advisory committees, Other: Travel Support, Speakers Bureau; Baxter: Other: Travel Support, Speakers Bureau; Alexion: Other: Travel Support, Speakers Bureau; Siemens: Other: Travel Support, Speakers Bureau; Bayer: Other: Travel Support, Speakers Bureau; Roche: Other: Travel Support, Speakers Bureau; Sanofi: Other: Travel Support, Speakers Bureau. Ruf: ARCA bioscience: Consultancy, Patents & Royalties; ICONIC Therapeutics: Consultancy; MeruVasimmune: Current holder of individual stocks in a privately-held company.

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The role of thrombosis

10.1093/med/9780199656653.003.0004 ◽

2015 ◽

Author(s):

Elena M. Faioni ◽

Maddalena Lettino ◽

Marco Cattaneo

Keyword(s):

Thrombus Formation ◽

Plaque Formation ◽

Primary And Secondary Prevention ◽

Flow Disturbance ◽

Vessel Occlusion ◽

Atherosclerotic Lesions ◽

Sequence Of Events ◽

Vessel Lumen ◽

Chronic Activation

This chapter is concerned with the sequence of events leading to thrombosis and its consequences. Acute thrombotic occlusions of arterial vessels, which may precipitate myocardial infarction and/or stroke, are often due to fissure of an atherosclerotic plaque, with consequent activation of haemostasis and clot formation. Arterial thrombosis also plays a crucial role in accelerating progression of atherosclerotic lesions. Chronic activation of endothelium, platelets, and leucocytes leads to plaque formation, while acute events, related to a flare-up of inflammation, precipitate plaque fissure and thereby promote thrombus formation on the plaque, partial or total vessel occlusion, and flow disturbance. Thrombus-derived proteins stimulate plaque growth and progression, and the thrombus itself is incorporated into the plaque, further restricting the vessel lumen. Detailed understanding of these various events is required if the success of primary and secondary prevention is to be improved.

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Protective Effects of Kininogen-1 Gene Deficiency in Mouse Models of Venous Thrombosis

Blood ◽

10.1182/blood-2021-153316 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 289-289

Author(s):

Aatira Vijay ◽

Mohamad B Kassab ◽

Young Jun Shim ◽

Shadi Swaidani ◽

Adam Mauskapf ◽

...

Keyword(s):

Venous Thrombosis ◽

Thrombus Formation ◽

Vena Cava ◽

Continuous Light ◽

Light Irradiation ◽

Fluorescence Angiography ◽

Contact Activation ◽

Tail Vein ◽

Platelet Accumulation

Abstract Background- High molecular weight Kininogen (HK) is a nonenzymatic co-factor of the contact activation system. HK binds prekallikrein (PK) and FXI to surfaces in proximity to FXII, amplifying PK activation by FXIIa and the reciprocal activation of FXII by activated PK (PKa), as well as FXI activation of FXIIa. PKa cleavage of HK also liberates bradykinin-a proinflammatory and vasoactive nanopeptide. The aim of this study was to define the pro-thrombotic role of kininogen in venous thrombosis (VT) and to use in vivo serial analysis of thrombus development to understand the recruitment and retention of platelets in the growing thrombus in the absence and presence of kininogen. Methods- The development of VT in mice deficient in kininogen (mKng1-/-) was compared to that in their wild-type littermates. A femoral-saphenous stasis VT model was prepared by ligating both saphenous and femoral veins. Next VT formation, growth, and dissolution (n=3 for each group) was monitored using intravital microscopy (IVM) via a multichannel epifluorescence microscope (Nikon Eclipse 90i). To induce stasis VT, FITC-dextran (10 mg/kg, ex/em 488/520 nm) was injected retro-orbitally, and then continuous light irradiation (20x objective, 475nm/35nm) of the saphenous vein was applied for 5 minutes. FITC-dextran fluorescence angiography monitored thrombus formation and dissolution. Immediately after VT formation, platelet accumulation at the thrombus site was monitored in the Cy5 channel (630/38 nm) via injection of a GPIbβ antibody conjugated with Dylight-649 (150nmol/kg), over time. All images were identically windowed in each channel, and thrombus area was measured using NIH ImageJ software. To corroborate IVM studies, we also evaluated a complete stasis model of inferior vena cava (IVC) ligation (n=7-8 per group). Thrombi were harvested after 48 hours and thrombus weight and length were measured to estimate thrombus mass. FXI circulates in blood as a homodimer along with HK. We determined the effect of kininogen deficiency on FXI activity. FXI activity assay used a combination of inhibitors, serially, to monitor the cleavage of substrate specific to activated FXI and release of chromogen, as a function of FXI activity. Finally, to determine the effects of Kng1 deficiency on bleeding, tail vein bleeding times were also determined (n=8 per group). Results- In femoral-saphenous stasis VT, thrombus developed in both groups immediately following FITC-channel light irradiation. However, thrombus size was smaller in Kng1-/- as compared to WT (Figure 1). Results from serial IVM of VT indicated faster thrombus dissolution in the Kng1-/- group. Lower platelet signals, as shown at 2 and 6 hours in the Kng1-/- mice may be consistent with this hypothesis. Thrombus area analysis suggested decreased thrombus formation in the Kng1-/- animals, and temporal analysis indicated faster dissolution by 6 hours (Figure 2). IVC ligation results corroborated the findings of femoral-saphenous DVT model, demonstrating that thrombus weight was significantly lower in Kng1-/- mice as compared to WT (p<0.001, Figure 3). FXI activity was also decreased in the Kng1-/- group (p<0.10). Tail vein bleeding times, however, showed no increased bleeding in Kng1-/- mice. Conclusion- These initial results suggest a pro-thrombotic role of kininogen and a protective role of kininogen deficiency in two murine venous thrombosis models, without incurring a bleeding penalty. Thrombus dissolution was faster and platelet accumulation was inhibited in Kng1-/- mice. These findings suggest that targeting kininogen may provide a new approach to prevent and treat venous thrombosis. Figure 1 Figure 1. Disclosures McCrae: Dova, Novartis, Rigel, and Sanofi Genzyme: Consultancy; Sanofi, Novartis, Alexion, and Johnson & Johnson: Consultancy, Honoraria. Jaffer: Mercator, Inc.: Other: Sponsred research.

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Cadherin-6 Forms a Functional Adhesion Complex with Alpha-Catenin and Beta-Catenin in Platelets and Is Required for Platelet Aggregation and Thrombus Formation

Blood ◽

10.1182/blood.v126.23.2232.2232 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2232-2232 ◽

Cited By ~ 1

Author(s):

Michele Mumaw ◽

Maria de la Fuente ◽

Carolyn Aldana ◽

Wei Li ◽

Marvin T Nieman

Keyword(s):

Platelet Aggregation ◽

Adhesion Molecules ◽

Platelet Adhesion ◽

Thrombus Formation ◽

Bleeding Complications ◽

Severe Bleeding ◽

Beta Catenin ◽

Adhesion Complex

Abstract The regulation of hemostasis and thrombus formation is a tightly controlled event that has catastrophic consequences when it is deregulated. One of the hallmarks of the thrombus is aggregated platelets. Upon platelet stimulation, adhesion molecules become activated and mediate multiple cell-cell interactions. Therapeutically, blocking platelet adhesion is a proven method for preventing pathological arterial thrombus formation. However, targeting the primary adhesion receptor, integrin αIIbβ3, results in severe bleeding complications. Therefore, identifying novel proteins or uncovering novel functions for known proteins in platelets is a necessary first step to facilitate the development of safer anti-platelet therapeutics. We have identified that the cell adhesion molecule cadherin-6 forms a functional adhesion complex with α-catenin and β-catenin in platelets. The goal of our project was to determine the mechanism of cadherin-6 mediated adhesion in platelets. Our initial experiments demonstated that cadherin-6 and β-catenin co-localize at the plasma membrane in platelets using confocal immunofluorescence microscopy. We determined that α-catenin and β-catenin co-immunoprecipitate with cadherin-6 from platelet lysates. To examine the functional role of cadherin-6 on platelet aggregation we used a cadherin-6 blocking antibody (10 μg/ml). Blocking cadherin-6 inhibited mouse platelet aggregation induced by PAR4 peptide. We next determined the role of cadherin-6 in vivo by examining carotid artery thrombosis after 7.5% FeCl3 treatment. C57Bl6 mice were injected with cadherin-6 antibody IV and labeled with rhodamine 6G by jugular vein injection. Thrombus formation was imaged in real time by fluorescent intravital microscopy. Blocking cadherin-6 prevented thrombosis for the duration of the experiment (30 min). To verify that the effects that we observed were specific to cadherin-6 expressed on platelets, we isolated platelets from donor mice and treated with cadherin-6 antibody or control IgG ex vivo. The treated platelets were perfused into recipient mice that were irradiated with 11 Gy to make the animals thrombocytopenic. The cadherin-6 antibody treated platelets formed an occlusion at 26.4 ± 3.6 min vs. 13.7 ± 2.0 min for the IgG (p=0.03). Importantly, the cadherin-6 antibody did not affect platelet counts compared to IgG controls 2.97 ± 0.40 (×108) vs. 3.02 ± 0.20 (×108). These combined studies show that caderhin-6 forms a complex with the necessary proteins required to mediate adhesion in platelets. Our results demonstrate that platelet cadherin-6 has a physiologically important role during platelet activation and thrombus formation in vivo. In summary, we have identified a novel adhesion complex in platelets that may provide a mechanism to limit platelet aggregation therapeutically. On going studies will determine the regulation of the cadherin-6/catenin complex and how cadherin-6 cooperates with other platelet adhesion molecules. Disclosures No relevant conflicts of interest to declare.

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Endothelial Dysfunction in Pulmonary Hypertension: Cause or Consequence?

Biomedicines ◽

10.3390/biomedicines9010057 ◽

2021 ◽

Vol 9 (1) ◽

pp. 57

Author(s):

Kondababu Kurakula ◽

Valérie F.E.D. Smolders ◽

Olga Tura-Ceide ◽

J. Wouter Jukema ◽

Paul H. A. Quax ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Therapeutic Potential ◽

Thrombus Formation ◽

Pulmonary Arteries ◽

Mesenchymal Transition ◽

Pulmonary Arterial ◽

Pulmonary Artery Smooth Muscle ◽

Endothelial To Mesenchymal Transition ◽

Molecular Signals

Pulmonary arterial hypertension (PAH) is a rare, complex, and progressive disease that is characterized by the abnormal remodeling of the pulmonary arteries that leads to right ventricular failure and death. Although our understanding of the causes for abnormal vascular remodeling in PAH is limited, accumulating evidence indicates that endothelial cell (EC) dysfunction is one of the first triggers initiating this process. EC dysfunction leads to the activation of several cellular signalling pathways in the endothelium, resulting in the uncontrolled proliferation of ECs, pulmonary artery smooth muscle cells, and fibroblasts, and eventually leads to vascular remodelling and the occlusion of the pulmonary blood vessels. Other factors that are related to EC dysfunction in PAH are an increase in endothelial to mesenchymal transition, inflammation, apoptosis, and thrombus formation. In this review, we outline the latest advances on the role of EC dysfunction in PAH and other forms of pulmonary hypertension. We also elaborate on the molecular signals that orchestrate EC dysfunction in PAH. Understanding the role and mechanisms of EC dysfunction will unravel the therapeutic potential of targeting this process in PAH.

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Altered thrombus formation in von Willebrand factor–deficient mice expressing von Willebrand factor variants with defective binding to collagen or GPIIbIIIa

Blood ◽

10.1182/blood-2008-02-142943 ◽

2008 ◽

Vol 112 (3) ◽

pp. 603-609 ◽

Cited By ~ 50

Author(s):

Isabelle Marx ◽

Olivier D. Christophe ◽

Peter J. Lenting ◽

Alain Rupin ◽

Marie-Odile Vallez ◽

...

Keyword(s):

Von Willebrand Factor ◽

Thrombus Formation ◽

Vessel Occlusion ◽

Injury Model ◽

Von Willebrand ◽

Willebrand Factor ◽

Deficient Mice ◽

Interesting Alternative ◽

Model Expression

Abstract The role of von Willebrand factor (VWF) in thrombosis involves its binding to a number of ligands. To investigate the relative importance of these particular interactions in the thrombosis process, we have introduced mutations into murine VWF (mVWF) cDNA inhibiting VWF binding to glycoprotein (Gp) Ib, GPIIbIIIa, or to fibrillar collagen. These VWF mutants were expressed in VWF-deficient mice (VWF−/−) by using an hydrodynamic injection approach, and the mice were studied in the ferric chloride–induced injury model. Expression of the collagen and the GPIIbIIIa VWF-binding mutants in VWF−/− mice resulted in delayed thrombus growth and significantly increased vessel occlusion times compared with mice expressing wild-type (WT) mVWF (30 ± 3 minutes and 38 ± 4 minutes for the collagen and GPIIbIIIa mutants, respectively, vs 19 ± 3 minutes for WT mVWF). Interestingly, these mutants were able to correct bleeding time as efficiently as WT mVWF. In contrast, VWF−/− mice expressing the GPIb binding mutant failed to restore thrombus formation and were bleeding for as long as they were observed, confirming the critical importance of the VWF-GPIb interaction. Our observations suggest that targeting the VWF-collagen or VWF-GPIIbIIIa interactions could be an interesting alternative for new antithrombotic strategies.

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The role of oral anticoagulant therapy in patients with acute coronary syndrome

Therapeutic Advances in Hematology ◽

10.1177/2040620717733691 ◽

2017 ◽

Vol 8 (12) ◽

pp. 353-366 ◽

Cited By ~ 12

Author(s):

Jae Youn Moon ◽

Deepa Nagaraju ◽

Francesco Franchi ◽

Fabiana Rollini ◽

Dominick J. Angiolillo

Keyword(s):

Acute Coronary Syndrome ◽

Anticoagulant Therapy ◽

Oral Anticoagulant ◽

Thrombus Formation ◽

Oral Anticoagulant Therapy ◽

Ease Of Use ◽

Coagulation Cascade ◽

Bleeding Complications ◽

Coronary Syndrome

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor antagonist represents the current standard of care to prevent atherothrombotic recurrences in patients with acute coronary syndrome (ACS). However, despite the use of DAPT, the recurrence rate of cardiovascular ischemic events still remains high. This persistent risk may be in part attributed to the sustained activation of the coagulation cascade leading to generation of thrombin, which may continue to play a key role in thrombus formation. The use of vitamin K antagonists (VKAs) as a strategy to reduce atherothrombotic recurrences after an ACS has been previously tested, leading to overall unfavorable outcomes due to the high risk of bleeding complications. The recent introduction of non-VKA oral anticoagulants (NOACs), characterized by a better safety profile and ease of use compared with VKA, has led to a reappraisal of the use of oral anticoagulant therapy for secondary prevention in ACS patients. The present article provides an overview of the rationale and prognostic role of oral anticoagulant therapy in ACS patients as well as recent updated clinical data, in particular with NOACs, in the field and future perspectives on this topic.

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Abstract 21: The Calcium-Binding Protein S100A1 Negatively Regulates Collagen-Dependent Platelet Activation and Thrombosis in Mice

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.34.suppl_1.21 ◽

2014 ◽

Vol 34 (suppl_1) ◽

Author(s):

Yacine Boulaftali ◽

David S Paul ◽

Raymond Piatt ◽

Dengmin Feng ◽

Brian C Cooley ◽

...

Keyword(s):

Carotid Artery ◽

Platelet Activation ◽

Calcium Binding ◽

Thrombus Formation ◽

Fold Increase ◽

Negative Regulator ◽

Vessel Occlusion ◽

Thrombosis Model ◽

Group A

Introduction: S100A1 is a member of the S100 family of calcium-binding proteins. S100A1 controls Ca2+ dynamics in cardiomyocytes and plays an important role in heart failure. S100A1 is also strongly expressed in mouse platelets, but its role in platelet biology has not been investigated. Goal: To determine the role of S100A1 in platelet activation and thrombosis. Methods and Results: Platelet activation in response to threshold levels of convulxin, a specific agonist for the collagen receptor GPVI, showed significantly increased activation of αIIbβ3 integrin and α-granule release in S100A1-deficient (SKO) platelets compared with wild-type (WT) platelets. Consistently, SKO platelets also showed a more robust aggregation response to convulxin and collagen. In contrast, SKO platelets responded normally to stimulation with PAR4 receptor-activating peptide or ADP. Adhesion of SKO platelets to collagen under flow conditions was not significantly different to that of WT platelets. However, we observed a ~3-fold increase in phosphatidylserine (PS)-positive SKO platelets bound to the collagen surface (p<0.001, n=9 mice/group), suggesting that S100A1 also regulates the procoagulant response in platelets. Consistent with this hypothesis, we observed increased coated platelet formation and more sustained calcium transients in SKO platelets compared to controls. The increased reactivity of SKO platelets to GPVI agonists is explained by a ~1.5-fold increase in GPVI receptors expressed on the surface of these cells (p<0.001, n=20 mice/group). A similar increase in GPVI expression was also found in bone marrow-derived megakaryocytes. When subjected to the FeCl3 carotid artery thrombosis model, the time to vessel occlusion was significantly shorter in SKO mice compared to WT controls (4.55 ± 0.27 min vs 7.00 ± 0.62 min, respectively; p<0.01; n=8 mice/group). Furthermore, by using a collagen-rich adventitial surface inserted intralumenally in the carotid artery, we observed that thrombus formation in SKO mice is significantly more stable compared to WT mice (p=0.01, n=7 WT, n=8 SKO) Conclusions: We here identify S100A1 as a negative regulator of GPVI expression and collagen-dependent platelet activation and thrombosis in mice.

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Treatment of Theophylline Poisoning

PEDIATRICS ◽

10.1542/peds.90.5.781 ◽

1992 ◽

Vol 90 (5) ◽

pp. 781-781

Author(s):

MICHAEL SHANNON ◽

GIL WERN0VSKY

Keyword(s):

Activated Charcoal ◽

Multiple Dose ◽

Congenital Heart ◽

Inferior Vena ◽

Vena Cava ◽

Complex Congenital Heart Disease ◽

Inferior Vena Cava Occlusion ◽

Theophylline Poisoning ◽

Theophylline Intoxication

In Reply.— We appreciate the comments of Strauss and Modanlou on the role of multiple-dose activated charcoal in the treatment of infants with severe theophylline intoxication. We are aware of both studies which they have published in this area and have also used multiple-dose charcoal in neonates.1-3 The infant in our case report was not considered a candidate for multiple-dose activated charcoal because of the absence of bowel sounds. He was also not a candidate for hemodialysis or hemoperfusion because of problems with vascular access which resulted from his complex congenital heart disease (including inferior vena cava occlusion and inaccessible subclavian veins).

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Abstract 605: Activation of NLRP3 Inflammasome Complex Regulates the Onset of Hypoxia Induced Thrombosis

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.35.suppl_1.605 ◽

2015 ◽

Vol 35 (suppl_1) ◽

Author(s):

Neha Gupta ◽

Manish Sharma ◽

Tathagata Chatterjee ◽

Tarun Tyagi ◽

Anita Sahu ◽

...

Keyword(s):

Platelet Aggregation ◽

Nlrp3 Inflammasome ◽

Thrombus Formation ◽

Vena Cava ◽

Early Response ◽

Sterile Inflammation ◽

Coagulation System ◽

Additional Risk Factor ◽

Whole Transcriptome Analysis

Objective: Besides well known predisposing conditions such as cancer, diabetes, cardiovascular disease and surgery; hypoxia per se has been suggested to be an additional risk factor for venous thrombosis (VT). We have recently shown that hypoxia, either localized due to stasis, or systemic, due to environmental factors such as high altitude exposure, results in a prothrombotic milieu. The proteomic analysis implicated some novel plasma factors that could trigger thrombotic propensity; however, the exact mechanism involved still remains poorly understood. Methods & Results: Effect of hypoxia on coagulation system was analysed using inferior vena cava ligation and simulated hypobaric hypoxia rat models. Data demonstrated that hypoxia modulates both coagulation and fibrinolytic pathways and thrombus developed under hypoxic atmospheres is an aggravated form of thrombus progression under normoxic environments. Moreover, the whole transcriptome analysis using RNA sequencing approach implicated the novel role of NOD Like receptors3 (NLRP3) and inflammasome in thrombus formation suggesting the hypoxia induced thrombosis to be an episode of sterile inflammation. The cytokine array profiling and immunofloroscence data also supported the role of innate immune components. Both pharmacological inhibition and siRNA mediated knockdown of caspase-1 and NLRP-3 respectively reinforced that the activation of NLRP3-inflammasome complex critically regulates thrombogenesis in response to hypoxia. This complex is likely to be activated as an early response to hypoxia, which precedes the platelet aggregation and hence, onset of thrombosis. The translational implication of this novel finding was evident by activation of NLRP3 inflammasome components in human patients who developed VT under hypoxic environments. Conclusions: The current study reveals a novel role of NLRP3 inflammasome in thrombosis induced by localised as well as systemic hypoxic environments. Further, the production of IL-1β by NLRP3 inflammasome augments platelet aggregation, the key event for thrombogenesis.

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