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A novel canine model of immune thrombocytopenia: has immune thrombocytopenia (ITP) gone to the dogs?

ABSTRACT: Canine immune thrombocytopenia (ITP) is analogous to human ITP, with similar platelet counts and heterogeneity in bleeding phenotype among affected individuals. With a goal of ultimately investigating this bleeding heterogeneity, a canine model of antibody-mediated ITP was developed. Infusion of healthy dogs with 2F9, a murine IgG2a monoclonal antibody to the canine platelet glycoprotein GPIIb (a common target of autoantibodies in ITP) resulted in profound, dose-dependent thrombocytopenia. Model dogs developed variable bleeding phenotypes, e.g. petechiae and haematuria, despite similar degrees of thrombocytopenia. 2F9 infusion was not associated with systemic inflammation, consumptive coagulopathy, or impairment of platelet function. Unexpectedly however, evaluation of cytokine profiles led to the identification of platelets as a potential source of serum interleukin-8 (IL8) in dogs. This finding was confirmed in humans with ITP, suggesting that platelet IL8 may be a previously unrecognized modulator of platelet-neutrophil crosstalk. The utility of this model will allow future study of bleeding phenotypic heterogeneity including the role of neutrophils and endothelial cells in ITP.

SUBMITTER: LeVine DN

PROVIDER: S-EPMC4167465 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

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A novel canine model of immune thrombocytopenia: has immune thrombocytopenia (ITP) gone to the dogs?

LeVine Dana N DN Birkenheuer Adam J AJ Brooks Marjory B MB Nordone Shila K SK Bellinger Dwight A DA Jones Sam L SL Fischer Thomas H TH Oglesbee Stephen E SE Frey Kahlina K Brinson Nicole S NS Peters Allison P AP Marr Henry S HS Motsinger-Reif Alison A Gudbrandsdottir Sif S Bussel James B JB Key Nigel S NS

British journal of haematology 20140708 1

Canine immune thrombocytopenia (ITP) is analogous to human ITP, with similar platelet counts and heterogeneity in bleeding phenotype among affected individuals. With a goal of ultimately investigating this bleeding heterogeneity, a canine model of antibody-mediated ITP was developed. Infusion of healthy dogs with 2F9, a murine IgG2a monoclonal antibody to the canine platelet glycoprotein GPIIb (a common target of autoantibodies in ITP) resulted in profound, dose-dependent thrombocytopenia. Model ...[more]

PMID: 25039744

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Project description:Primary immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by isolated thrombocytopenia caused by increased platelet destruction and impaired platelet production. First-line therapies include corticosteroids, intravenous immunoglobulin, and anti-D immunoglobulin. For patients who are refractory to these therapies, those who become corticosteroid dependent, or relapse following treatment with corticosteroid, options include splenectomy, rituximab, and thrombopoietin-receptor agonists, alongside a variety of additional immunosuppressive and experimental therapies. Despite recent advances in the management of ITP, many areas need further research. Although it is recognized that an assessment of patient-reported outcomes in ITP is valuable to understand and guide treatment, these measures are not routinely measured in the clinical setting. Consequently, although corticosteroids are first-line therapies for both children and adults, there are no data to suggest that corticosteroids improve health-related quality of life or other patient-related outcomes in either children or adults. In fact, long courses of corticosteroids, in either children or adults, may have a negative impact on a patient's health-related quality of life, secondary to the impact on sleep disturbance, weight gain, and mental health. In adults, additional therapies may be needed to treat overt hemorrhage, but unfortunately the results are transient for the majority of patients. Therefore, there is a need to recognize the limitations of current existing therapies and evaluate new approaches, such as individualized treatment based on the probability of response and the size of effect on the patient's most bothersome symptoms and risk of adverse effects or complications. Finally, a validated screening tool that identifies clinically significant patient-reported outcomes in routine clinical practice would help both patients and physicians to effectively follow a patient's health beyond simply treating the laboratory findings and physical symptoms of ITP. The goal of this narrative review is to discuss management of newly diagnosed and refractory patients with ITP, with a focus on the limitations of current therapies from the patient's perspective.

Project description:Bleeding heterogeneity amongst patients with immune thrombocytopenia (ITP) is poorly understood. Platelets play a role in maintaining endothelial integrity, and variable thrombocytopenia-induced endothelial changes may influence bleeding severity. Platelet-derived endothelial stabilizers and markers of endothelial integrity in ITP are largely underexplored. We hypothesized that, in a canine ITP model, thrombocytopenia would lead to alterations in the endothelial ultrastructure and that the Von Willebrand factor (vWF) would serve as a marker of endothelial injury associated with thrombocytopenia. Thrombocytopenia was induced in healthy dogs with an antiplatelet antibody infusion; control dogs received an isotype control antibody. Cutaneous biopsies were obtained prior to thrombocytopenia induction, at platelet nadir, 24 hours after nadir, and on platelet recovery. Cutaneous capillaries were assessed by electron microscopy for vessel thickness, the number of pinocytotic vesicles, the number of large vacuoles, and the number of gaps between cells. Pinocytotic vesicles are thought to represent an endothelial membrane reserve that can be used for repair of damaged endothelial cells. Plasma samples were assessed for vWF. ITP dogs had significantly decreased pinocytotic vesicle numbers compared to control dogs (P = 0.0357) and the increase in plasma vWF from baseline to 24 hours correlated directly with the endothelial large vacuole score (R = 0.99103; P < 0.0001). This direct correlation between plasma vWF and the number of large vacuoles, representing the vesiculo-vacuolar organelle (VVO), a permeability structure, suggests that circulating vWF could serve as a biomarker for endothelial alterations and potentially a predictor of thrombocytopenic bleeding. Overall, our results indicate that endothelial damage occurs in the canine ITP model and variability in the degree of endothelial damage may account for differences in the bleeding phenotype among patients with ITP.

Dataset Information

A novel canine model of immune thrombocytopenia: has immune thrombocytopenia (ITP) gone to the dogs?

Publications

A novel canine model of immune thrombocytopenia: has immune thrombocytopenia (ITP) gone to the dogs?

Similar Datasets

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