murine-model-cerebral-venous-outflow-occlusion-through-bilateral

Murine Model of Cerebral Venous Outflow Occlusion Through Bilateral Ligation of Jugular Veins

Lymphatic vessels play a key role in maintaining fluid homeostasis and immune surveillance within tissues. At the brain's border, the dural meninges ...

Université Paris Cité

Cerebral venous sinus thrombosis (CVST) is an uncommon cause of stroke resulting in parenchymal injuries associated with heterogeneous clinical symptoms and prognosis. Therefore, an experimental animal model is required to further study underlying mechanisms involved in CVST. This study is aimed at developing a novel murine model suitable and relevant for evaluating injury patterns during CVST and studying its clinical aspects. CVST was achieved in C57BL/6J mice by autologous clot injection into the superior sagittal sinus (SSS) combined with bilateral ligation of external jugular veins. Clot was prepared ex vivo using thrombin before injection. On days 1 and 7 after CVST, SSS occlusion and associated-parenchymal lesions were monitored using different modalities: in vivo real-time intravital microscopy, magnetic resonance imaging (MRI), and immuno-histology. In addition, mice were subjected to a neurological sensory-motor evaluation. Thrombin-induced clot provided fibrin- and erythrocyte-rich thrombi that lead to reproducible SSS occlusion at day 1 after CVST induction. On day 7 post-CVST, venous occlusion monitoring (MRI, intravital microscopy) showed that initial injected-thrombus size did not significantly change demonstrating no early spontaneous recanalization. Microscopic histological analysis revealed that SSS occlusion resulted in brain edema, extensive fibrin-rich venular thrombotic occlusion, and ischemic and hemorrhagic lesions. Mice with CVST showed a significant lower neurological score on post-operative days 1 and 7, compared to the sham-operated group. We established a novel clinically CVST-relevant model with a persistent and reproducible SSS occlusion responsible for symptomatic ischemic and hemorrhagic lesions. This method provides a reliable model to study CVST physiopathology and evaluation of therapeutic new regimens.

A Novel Mouse Model for Cerebral Venous Sinus Thrombosis.

Cerebral venous sinus thrombosis (CVST) is an uncommon venous thromboembolic event accounting for less than 1% of strokes resulting in brain parenchymal injuries. Diagnosis and prognosis are still challenging due to highly variable clinical course and etiologies. Beyond thrombosis, different CVST-related parenchymal injuries may occur and include edema, ischemic strokes, and intra-cerebral hemorrhage (ICH; i.e., parenchymal/subdural hematomas, and subarachnoid hemorrhages), which are identified in 40%-60% of patients without clearly identified mechanisms. In this perspective, experimental animal models contribute to the understanding of initiation, propagation, and resolution of thrombosis, as well as brain-related damages. Last but not least, animal models may be useful to study new therapeutic approaches. In this review, we provide a comprehensive overview of CVST experimental models, focusing on their strengths, limits, and contribution to the current knowledge.

State of the art in cerebral venous sinus thrombosis animal models.

Bone marrow smear showing histiocytes (black arrow) containing sea blue granules stained with May-Grünwald Giemsa.

Pancytopenia related to acquired sea-blue histiocytosis during chronic parenteral nutrition.

Cerebral venous sinus thrombosis (CVST) is an uncommon venous thromboembolic event accounting for <1% of strokes resulting in brain parenchymal injuries. JAK2V617F mutation, the most frequent driving mutation of myeloproliferative neoplasms, has been reported to be associated with worse clinical outcomes in patients with CVST. We investigated whether hematopoietic JAK2V617F expression predisposes to specific pathophysiological processes and/or worse prognosis after CVST. Using an in vivo mouse model of CVST, we analyzed clinical, biological, and imaging outcomes in mice with hematopoietic-restricted Jak2V617F expression, compared with wild-type Jak2 mice. In parallel, we studied a human cohort of JAK2V617F-positive or -negative CVST. Early after CVST, mice with hematopoietic Jak2V617F expression had increased adhesion of platelets and neutrophils in cerebral veins located in the vicinity of CVST. On day 1, Jak2V617F mice had a worse outcome characterized by significantly more frequent and severe intracranial hemorrhages (ICHs) and higher mortality rates. Peripheral neutrophil activation was enhanced, as indicated by higher circulating platelet-neutrophil aggregates, upregulated CD11b expression, and higher myeloperoxydase plasma level. Concurrently, immunohistological and brain homogenate analysis showed higher neutrophil infiltration and increased blood-brain barrier disruption. Similarly, patients with JAK2V617F-positive CVST tended to present higher thrombotic burden and had significantly higher systemic immune-inflammation index, a systemic thromboinflammatory marker, than patients who were JAK2V617F-negative. In mice with CVST, our study corroborates that Jak2V617F mutation leads to a specific pattern including increased thrombotic burden, ICH, and mortality. The exacerbated thromboinflammatory response, observed both in mice and patients positive for JAK2V617F, could contribute to hemorrhagic complications.

Exacerbation of thromboinflammation by JAK2V617F mutation worsens the prognosis of cerebral venous sinus thrombosis.

Preoperative identification of patients with hemostasis abnormalities leading to an increased bleeding risk is based on routine hemostasis tests: prothrombin time (PT), activated partial thromboplastin time (APTT), and platelet count. Because of their low predictive performance, guidelines recommend replacing them with structured bleeding risk questionnaires, but none is validated in this population.

Sensitivity and specificity of strategies to identify patients with hemostasis abnormalities leading to an increased risk of bleeding before scheduled intervention: the Hemorisk study.

Myeloproliferative neoplasms (MPNs) are characterized by a high rate of thrombotic complications that contribute to morbidity and mortality. MPN-related thrombogenesis is assumed to be multifactorial, involving both procoagulant and proinflammatory processes. Whether impaired fibrinolysis also participates in the prothrombotic phenotype of MPN has been poorly investigated.

Impaired fibrinolysis in JAK2V617F-related myeloproliferative neoplasms.

Antiplatelet drugs represent potential candidates for protecting the penumbral microcirculation during cerebral ischemia and improving the benefits of arterial recanalization in ischemic stroke. Yet while the efficacy of such adjuvant strategies has been shown to be highly time dependent, antiplatelet therapy at the acute phase of ischemic stroke cannot be envisioned until the diagnosis of stroke and its ischemic nature have been confirmed because of the presumed risk of worsening bleeding in case of intracranial hemorrhage (ICH). Here, we investigated this risk for 2 antiplatelet drugs currently being tested in clinical trials for ischemic stroke, glenzocimab and eptifibatide, in 2 mouse models of ICH.

Article	Year
A Novel Mouse Model for Cerebral Venous Sinus Thrombosis. Translational stroke research\| PubMed ID: 33675011	2021
State of the art in cerebral venous sinus thrombosis animal models. Journal of thrombosis and haemostasis : JTH\| PubMed ID: 35815379	2022
Pancytopenia related to acquired sea-blue histiocytosis during chronic parenteral nutrition. American journal of hematology\| PubMed ID: 38115676	2024
Exacerbation of thromboinflammation by JAK2V617F mutation worsens the prognosis of cerebral venous sinus thrombosis. Blood advances\| PubMed ID: 38386979	2024
Sensitivity and specificity of strategies to identify patients with hemostasis abnormalities leading to an increased risk of bleeding before scheduled intervention: the Hemorisk study. Journal of thrombosis and haemostasis : JTH\| PubMed ID: 39128655	2024
Impaired fibrinolysis in JAK2V617F-related myeloproliferative neoplasms. Journal of thrombosis and haemostasis : JTH\| PubMed ID: 39260744	2024
Comparative Effects of Glenzocimab and Eptifibatide on Bleeding Severity in 2 Mouse Models of Intracranial Hemorrhage. Journal of the American Heart Association\| PubMed ID: 39818980	2025

Marie-Charlotte Bourrienne

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