Dataset Information

Toll-like receptors 2 and 7 mediate coagulation activation and coagulopathy in murine sepsis.

ABSTRACT: BACKGROUND:Sepsis is a life-threatening condition often manifested as marked inflammation and severe coagulopathy. Toll-like receptors (TLRs) play a pivotal role in inflammation, organ dysfunction and mortality in animal sepsis. OBJECTIVES:To investigate the role of TLR signaling in mediating sepsis-induced coagulopathy (SIC) in a mouse model. METHODS:Polymicrobial sepsis was created by cecal ligation and puncture (CLP) or fecal slurry peritoneal injection. To quantify global clotting function, two viscoelastic assays were performed with rotational thromboelastometry, and the results were presented as maximum clot firmness (MCF): (a) EXTEM to test tissue factor (TF)-initiated clot formation; and (b) FIBTEM to test EXTEM in the presence of a platelet inhibitor, cytochalasin D. Plasma coagulation factors were quantified with ELISA. TF gene expression and protein expression were determined with real-time quantitative reverse transcription PCR and flow cytometry, respectively. RESULTS:Between 4 and 24 hours after CLP surgery, wild-type mice showed significant MCF reduction in both EXTEM and FIBTEM tests. This was accompanied by marked thrombocytopenia and a significant increase in the levels of plasminogen activator inhibitor-1, plasma TF, and D-dimer. In comparison, TLR2-/- and TLR7-/- CLP mice showed preserved MCF and platelet counts, and near-normal plasma TF levels. Bone marrow-derived macrophages treated with a TLR2 agonist Pam3cys-Ser-(Lys)4 (Pam3cys) or a TLR7 agonist (R837) showed marked increases in TF gene expression and protein expression. MicroRNA-146a, a newly identified proinflammatory mediator that is upregulated during sepsis, induced TF production via a TLR7-dependent mechanism. CONCLUSIONS:Murine sepsis leads to an increased procoagulant response, thrombocytopenia, and global coagulopathy. TLR2 and TLR7 play an important role in procoagulant production and in SIC.

SUBMITTER: Williams B

PROVIDER: S-EPMC7197442 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Toll-like receptors 2 and 7 mediate coagulation activation and coagulopathy in murine sepsis.

Williams Brittney B Neder Jessica J Cui Ping P Suen Andrew A Tanaka Kenichi K Zou Lin L Chao Wei W

Journal of thrombosis and haemostasis : JTH 20190723 10

<h4>Background</h4>Sepsis is a life-threatening condition often manifested as marked inflammation and severe coagulopathy. Toll-like receptors (TLRs) play a pivotal role in inflammation, organ dysfunction and mortality in animal sepsis.<h4>Objectives</h4>To investigate the role of TLR signaling in mediating sepsis-induced coagulopathy (SIC) in a mouse model.<h4>Methods</h4>Polymicrobial sepsis was created by cecal ligation and puncture (CLP) or fecal slurry peritoneal injection. To quantify glob ...[more]

PMID: 31211901

Similar Datasets

Project description:Essential thrombocythemia (ET) is comprised among chronic myeloproliferative neoplasms (MPN) and is caused by driver mutations in JAK2, CALR, and MPL, which lead to megakaryocyte proliferation and prominent thrombocytosis. Thrombosis remains the main cause of morbidity in ET and is driven by the interplay between blood cells, the endothelium, the clotting cascade, and host-derived inflammatory mediators. Platelet activation plays a key role in the thrombotic predisposition, although the underlying mechanisms remain poorly defined. In addition to their role in hemostasis, platelets participate in innate immunity and inflammation owing to the expression of toll-like receptors (TLR), which recognize inflammatory signals, triggering platelet functional responses. Considering the impact of inflammation on ET procoagulant state, we assessed the contribution of TLR2 and TLR4 to platelet hemostatic and inflammatory properties in ET patients, by using Pam3CSK4 and lipopolysaccharide (LPS) as specific TLR2 and TLR4 ligands, respectively. TLR2 ligation induced increased surface translocation of ?-granule-derived P-selectin and CD40L, which mediate platelet interaction with leukocytes and endothelial cells, respectively, and higher levels of dense granule-derived CD63 in patients, whereas PAC-1 binding was not increased and LPS had no effect on these platelet responses. Platelet-neutrophil aggregate formation was elevated in ET at baseline and after stimulation of both TLR2 and TLR4. In addition, ET patients displayed higher TLR2- and TLR4-triggered platelet secretion of the chemokine RANTES (CCL5), whereas von Willebrand factor release was not enhanced, revealing a differential releasate pattern for ?-granule-stored inflammatory molecules. TLR-mediated hyperresponsiveness contrasted with impaired or preserved responses to classic platelet hemostatic agonists, such as TRAP-6 and thrombin. TLR2 and TLR4 expression on the platelet surface was normal, whereas phosphorylation of downstream effector ERK1/2 was higher in patients at baseline and after incubation with Pam3CSK4, which may partly explain the enhanced TLR2 response. In conclusion, exacerbated response to TLR stimulation may promote platelet activation in ET, boosting platelet/leukocyte/endothelial interactions and secretion of inflammatory mediators, overall reinforcing the thromboinflammatory state. These findings highlight the role of platelets as inflammatory sentinels in MPN prothrombotic scenario and provide additional evidence for the close intertwining between thrombosis and inflammation in this setting.

Project description:IntroductionTraumatic brain injury (TBI) induces acute hypocoagulability, subacute hypercoagulability, and persistently elevated risk for thromboembolic events. Splenectomy is associated with increased mortality in patients with moderate or severe TBI. We hypothesized that the adverse effects of splenectomy in TBI patients may be secondary to the exacerbation of pathologic coagulation and platelet activation changes.MethodsAn established murine weight-drop TBI model was utilized and a splenectomy was performed immediately following TBI. Sham as well as TBI and splenectomy alone mice were used as injury controls. Mice were sacrificed for blood draws at 1, 6, and 24 h, as well as 7 days post-TBI. Viscoelastic coagulation parameters were assessed by rotational thromboelastometry (ROTEM) and platelet activation was measured by expression of P-selectin via flow cytometry analysis of platelet rich plasma samples.ResultsAt 6 h following injury, TBI/splenectomy demonstrated hypocoagulability with prolonged clot formation time (CFT) compared to TBI alone. By 24 h following injury, TBI/splenectomy and splenectomy mice were hypercoagulable with a shorter CFT, a higher alpha angle, and increased MCF, despite a lower percentage of platelet contribution to clot compared to TBI alone. However, only the TBI/splenectomy continued to display this hypercoagulable state at 7 days. While TBI/splenectomy had greater P-selectin expression at 1-h post-injury, TBI alone had significantly greater P-selectin expression at 24 h post-injury compared to TBI/splenectomy. Interestingly, P-selectin expression remained elevated only in TBI/splenectomy at 7 days post-injury.ConclusionSplenectomy following TBI exacerbates changes in the post-injury coagulation state. The combination of TBI and splenectomy induces an acute hypocoagulable state that could contribute to an increase in intracranial bleeding. Subacutely, the addition of splenectomy to TBI exacerbates post-injury hypercoagulability and induces persistent platelet activation. These polytrauma effects on coagulation may contribute to the increased mortality observed in patients with combined brain and splenic injuries.

Project description:OBJECTIVES:To assess the effects of recombinant human soluble thrombomodulin treatment on 28-day all-cause mortality in subgroups categorized by baseline coagulation biomarker levels (prothrombin fragment 1.2, thrombin-antithrombin complex, D-dimer) in patients with sepsis-associated coagulopathy in the Sepsis Coagulopathy Asahi Recombinant LE Thrombomodulin trial (SCARLET) (NCT01598831). DESIGN:Post hoc, subgroup analysis of a randomized, double-blind, placebo-controlled, multinational, multicenter phase 3 study. SETTING:ICUs at 159 sites in 26 countries. PATIENTS:Eight-hundred adults with sepsis-associated coagulopathy defined as international normalized ratio greater than 1.40 and platelet count between 30 × 10/L and 150 × 10/L or greater than 30% decrease within 24 hours with concomitant cardiovascular and/or respiratory failure. INTERVENTIONS:Patients randomized and treated with recombinant human soluble thrombomodulin (0.06 mg/kg/d; n = 395) or equivalent placebo (n = 405) for 6 days. MEASUREMENTS AND MAIN RESULTS:Recombinant human soluble thrombomodulin did not significantly reduce 28-day all-cause mortality in the Sepsis Coagulopathy Asahi Recombinant LE Thrombomodulin trial: absolute risk reduction was 2.55% (p = 0.32) in patients with sepsis-associated coagulopathy. In this post hoc analysis, mortality steadily increased with increasing baseline prothrombin fragment 1.2 and thrombin-antithrombin complex levels in the placebo group; for those values exceeding the upper limit of normal, the mortality increases in the recombinant human soluble thrombomodulin group were lower or negligible with increasing baseline prothrombin fragment 1.2 and thrombin-antithrombin complex. Consequently, absolute risk reductions were greater in subgroups with higher baseline prothrombin fragment 1.2 or thrombin-antithrombin complex. Absolute risk reductions were also greater in subgroups with baseline coagulation biomarker levels at or above median of the entire study population, ranging from 4.2% (95% CI, -5.0% to 13.4%) to 5.5% (95% CI, -4.0% to 14.9%). CONCLUSIONS:Compared with patients receiving placebo, patients treated with recombinant human soluble thrombomodulin having higher baseline thrombin generation biomarker levels had lower mortality. Further research regarding the predictive role of coagulation biomarkers for recombinant human soluble thrombomodulin treatment response in sepsis-associated coagulopathy is warranted to evaluate clinical relevance.

Dataset Information

Toll-like receptors 2 and 7 mediate coagulation activation and coagulopathy in murine sepsis.

Publications

Toll-like receptors 2 and 7 mediate coagulation activation and coagulopathy in murine sepsis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets