scholarly journals A new mouse model mimicking thrombotic thrombocytopenic purpura: correction of symptoms by recombinant human ADAMTS13

Blood ◽  
2012 ◽  
Vol 119 (25) ◽  
pp. 6128-6135 ◽  
Author(s):  
Alexandra Schiviz ◽  
Kuno Wuersch ◽  
Christina Piskernik ◽  
Barbara Dietrich ◽  
Werner Hoellriegl ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Mouse Model ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Thrombotic Microangiopathy ◽  
Knockout Mice ◽  
Serum Lactate Dehydrogenase ◽  
Severe Thrombocytopenia ◽  
Dependent Manner ◽  
Thrombocytopenic Purpura ◽  
Induce Platelet Aggregation

Abstract Deficiency of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), a VWF-cleaving protease, is the key factor in the pathogenesis of thrombotic thrombocytopenic purpura (TTP), a life-threatening thrombotic microangiopathy. It is well established that ADAMTS13 deficiency results in elevated plasma levels of ultra-large VWF multimers (ULVWF), which are prone to induce platelet aggregation; however, the actual trigger of TTP development remains uncertain. Here we describe a new animal model in which some TTP-like symptoms can be triggered in ADAMTS13 knockout mice by challenge with 2000 units/kg body weight of recombinant human VWF containing ULVWF multimers. Animals rapidly showed clinical symptoms and developed severe thrombocytopenia. Schistocytosis, a decrease in hematocrit, and elevated serum lactate dehydrogenase levels were observed. The heart was identified as the most sensitive target organ with rapid onset of extensive platelet aggregation in the ventricles and myocardial necrosis. Prophylactic administration of 200 units/kg recombinant human ADAMTS13 protected ADAMTS13 knockout mice from developing TTP. Therapeutic administration of 320 units/kg rhADAMTS13 reduced the incidence and severity of TTP findings in a treatment interval-dependent manner. We therefore consider this newly established mouse model of thrombotic microangiopathy highly predictive for investigating the efficacy of new treatments for TTP.

Therapeutic Efficacy of Anfibatide in a Murine Model of Thrombotic Thrombocytopenic Purpura

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 659-659
Author(s):  
Liang Zheng ◽  
Yingying Mao ◽  
Mandy Li ◽  
Xiangrong Dai ◽  
Benjamin Li ◽  
...  
Keyword(s):  
Body Weight ◽  
Hong Kong ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Snake Venom ◽  
Murine Model ◽  
Saline Control ◽  
Severe Thrombocytopenia ◽  
Dependent Manner ◽  
Thrombocytopenic Purpura ◽  
Blood Disorder

Abstract Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially fatal blood disorder, resulting from severe deficiency of plasma ADAMTS13 activity. Plasma infusion or exchange is the mainstay of treatment. However, complications associated with the administration of blood products and with the placement of a central venous line remain to be a major concern. To address the unmet clinical need, we test hypothesis that anfibatide, a novel snake venom-derived glycoprotein (GP) Ib antagonist, may be efficacious in treating TTP. Here, we show that purified anfibatide from snake venom inhibited murine platelet agglutination induced by botrocetin in the presence of recombinant murine VWF in a concentration-dependent manner. At 6-9 micro grams per ml (final concentrations), anfibatide nearly completely abolished botrocetin-induced murine platelet agglutination (Fig. 1A). As expected, anfibatide at the same concentrations showed little or no inhibitory effect on the protease-activating receptor 4 (PAR4) agonist (AYPGKF)-induced murine platelet aggregation. In vivo, an intravenously infused radiolabeled anfibatide exhibited a half-life of 5-7 hours depending on the initial loading dose. This information provided pharmacokinetic basis for therapeutic strategy for TTP in the murine model. An infusion of purified anfibatide at the dose of 60-90 ng per gram of body weight twice daily significantly reduced the rate of thrombocytopenia in Adamts13-/- mice triggered by intravenous infusion of a bacterial toxin, i.e. shigatoxin-2 (Stx2) (250 pg per gram body weight). As shown, 5/5 (100%) Adamts13-/- mice after being challenged with Stx2 and but treated with normal saline (control) exhibited severe thrombocytopenia (defined by 50% reduction of platelet counts from the baseline). Similarly, treatment of Adamts13-/- mice with anfibatide at the dose of 30 ng per gram body weight twice daily had little or no effect in preventing thrombocytopenia. However, treatment of the same mice with anfibatide at doses of 60-90 ng per gram body weight twice daily resulted in significantly reduced rate of severe thrombocytopenia to 11%-37.5% (Fig. 1B). Our ongoing effort is to determine the efficacy of anfibatide in treatment of acquired TTP associated with inhibitors. We conclude that anfibatide when given at the optimal doses and interval can efficiently prevent Stx2-induced TTP syndrome in the murine model. These findings support a rationale for further development of anfibatide as a novel therapeutic for TTP in humans. Disclosures Li: 3Lee's Pharmaceutical Holdings Limited, Shatin, Hong Kong: Employment. Dai:4Zhaoke Pharmaceutical Co. Limited, Hefei, Anhui, China: Employment. Li:3Lee's Pharmaceutical Holdings Limited, Shatin, Hong Kong, China: Employment.

Thrombotic thrombocytopenic purpura directly linked with ADAMTS13 inhibition in the baboon (Papio ursinus)

Blood ◽  
2010 ◽  
Vol 116 (12) ◽  
pp. 2005-2010 ◽  
Author(s):  
Hendrik B. Feys ◽  
Jan Roodt ◽  
Nele Vandeputte ◽  
Inge Pareyn ◽  
Seb Lamprecht ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Hemolytic Anemia ◽  
Von Willebrand Factor ◽  
Disease Onset ◽  
Serum Lactate Dehydrogenase ◽  
Severe Thrombocytopenia ◽  
Thrombocytopenic Purpura ◽  
Papio Ursinus ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Thrombotic thrombocytopenic purpura (TTP) is the prototypical microangiopathy characterized by disseminated microthromboses, hemolytic anemia, and ultimately organ dysfunction. A link with deficiency of the von Willebrand factor–cleaving protease (ADAMTS13) has been demonstrated, but additional genetic and/or environmental triggers are thought to be required to incite acute illness. Here we report that 4 days of ADAMTS13 functional inhibition is sufficient to induce TTP in the baboon (Papio ursinus), in the absence of inciting triggers because injections with an inhibitory monoclonal antibody (mAb) consistently (n = 6) induced severe thrombocytopenia (< 12 × 109/L), microangiopathic hemolytic anemia, and a rapid rise in serum lactate dehydrogenase. Immunohistochemical staining revealed the characteristic disseminated platelet- and von Willebrand factor–rich thrombi in kidney, heart, brain, and spleen but not lungs. Prolonged inhibition (14 days, n = 1) caused myocardial ischemic damage and asplenia but not death. Control animals (n = 5) receiving equal doses of a noninhibitory anti-ADAMTS13 mAb remained unaffected. Our results provide evidence for a direct link between TTP and ADAMTS13 inhibition and for a mild disease onset. Furthermore, we present a reliable animal model of this disease as an opportunity for the development and validation of novel treatment strategies.

scholarly journals Diagnostic dilemma: Severe thrombotic microangiopathy in pregnancy

2017 ◽  
Vol 18 (4) ◽  
pp. 348-351 ◽  
Author(s):  
Sarah Birkhoelzer ◽  
Alexandra Belcher ◽  
Helen Peet
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Haemolytic Anaemia ◽  
Thrombotic Microangiopathy ◽  
Interdisciplinary Approach ◽  
Severe Thrombocytopenia ◽  
Diagnostic Dilemma ◽  
Thrombocytopenic Purpura ◽  
Microangiopathic Haemolytic Anaemia ◽  
Elevated Liver Enzymes ◽  
In Pregnancy

A diagnostic dilemma occurred when thrombotic microangiopathy developed during pregnancy. The diagnostic criteria of thrombotic microangiopathy include thrombocytopenia (platelets <100) and microangiopathic haemolytic anaemia (including thrombotic thrombocytopenic purpura and haemolytic-uraemic syndrome). An urgent interdisciplinary approach is required to treat thrombotic microangiopathy in pregnancy to differentiate between thrombotic microangiopathy and HELLP syndrome (haemolysis, elevated liver enzymes, low platelets).1 This case presented with the pentad of thrombotic thrombocytopenic purpura: severe thrombocytopenia (platelets 9 × 109/L), microangiopathic haemolytic anaemia (reticular count 245 × 109/L (20–110)), LDH >5000 U/L (<425)), neurological abnormalities (Glasgow Coma Scale 10/15), renal failure (creatinine 140 µmol/L (<97)), fever (37.7℃). A Disintegrin And Metalloproteinase with a Thrombospondin type 1 motif, member 13 (ADAMTS13) activity of less than 5% and anti-ADAMTS13 antibodies retrospectively confirmed the diagnosis of acquired idiopathic thrombotic thrombocytopenic purpura in pregnancy. The immediate management in the Emergency Department with an interdisciplinary team of Consultant Nephrologists, Intensivists, Haematologists and Obstetricians facilitated prompt diagnosis resulting in immediate plasma exchange (PEX) and coordination of semi-elective delivery of the foetus.

scholarly journals Thrombotic Thrombocytopenic Purpura: Pathophysiology, Diagnosis, and Management

2021 ◽  
Vol 10 (3) ◽  
pp. 536
Author(s):  
Senthil Sukumar ◽  
Bernhard Lämmle ◽  
Spero R. Cataland
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Initial Therapy ◽  
Fresh Frozen Plasma ◽  
Organ Injury ◽  
Severe Thrombocytopenia ◽  
Front Line ◽  
Thrombocytopenic Purpura ◽  
Fresh Frozen ◽  
Biallelic Mutations ◽  
Line Setting

Thrombotic thrombocytopenic purpura (TTP) is a rare thrombotic microangiopathy characterized by microangiopathic hemolytic anemia, severe thrombocytopenia, and ischemic end organ injury due to microvascular platelet-rich thrombi. TTP results from a severe deficiency of the specific von Willebrand factor (VWF)-cleaving protease, ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13). ADAMTS13 deficiency is most commonly acquired due to anti-ADAMTS13 autoantibodies. It can also be inherited in the congenital form as a result of biallelic mutations in the ADAMTS13 gene. In adults, the condition is most often immune-mediated (iTTP) whereas congenital TTP (cTTP) is often detected in childhood or during pregnancy. iTTP occurs more often in women and is potentially lethal without prompt recognition and treatment. Front-line therapy includes daily plasma exchange with fresh frozen plasma replacement and immunosuppression with corticosteroids. Immunosuppression targeting ADAMTS13 autoantibodies with the humanized anti-CD20 monoclonal antibody rituximab is frequently added to the initial therapy. If available, anti-VWF therapy with caplacizumab is also added to the front-line setting. While it is hypothesized that refractory TTP will be less common in the era of caplacizumab, in relapsed or refractory cases cyclosporine A, N-acetylcysteine, bortezomib, cyclophosphamide, vincristine, or splenectomy can be considered. Novel agents, such as recombinant ADAMTS13, are also currently under investigation and show promise for the treatment of TTP. Long-term follow-up after the acute episode is critical to monitor for relapse and to diagnose and manage chronic sequelae of this disease.

The occurrence of thrombotic thrombocytopenic purpura during treatment of HCV with direct-acting antiviral agents

2018 ◽  
Vol 1 (1) ◽  
pp. 1-9
Author(s):  
Amr Hanafy ◽  
◽  
Waseem Seleem ◽  
Salem Mohamed ◽  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Hemolytic Anemia ◽  
Peripheral Blood Smear ◽  
Hcv Infection ◽  
Severe Thrombocytopenia ◽  
Direct Acting Antivirals ◽  
Thrombocytopenic Purpura ◽  
Direct Acting Antiviral ◽  
Chronic Hcv ◽  
Direct Acting

Background and aim Experts have reported thrombocytopenia linked to chronic liver disease in up to 70% in patients with advanced fibrosis and portal hypertension. Thrombotic thrombocytopenic purpura (TTP) occurrence with HCV infection is a rare and life-threatening event. We aimed to investigate the cause of disturbed conscious level, acute hemolytic anemia, and severe thrombocytopenia in a male patient with chronic HCV and under treatment with direct-acting antivirals. Case report: Development of severe thrombocytopenia, acute hemolytic anemia, neurological symptoms in the form of fits and coma in a 32- year- old man with chronic HCV infection after one week of treatment with direct-acting antivirals (sofosbuvir 400mg PO daily, and daclatasvir 60 mg PO daily). Brain CT was normal, with a negative Coombs test and the presence of schistocytes in the peripheral blood smear. The patient presentation was suggestive of thrombotic thrombocytopenic purpura (TTP). Conclusion: This is a case of TTP after one week of direct-acting antiviral drugs despite the safety profile of these medications. Studying the pathophysiology of TTP after DAAs needs more clarifications.

scholarly journals Studies investigating platelet aggregation and release initiated by sera from patients with thrombotic thrombocytopenic purpura

Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 924-928 ◽  
Author(s):  
JG Kelton ◽  
JC Moore ◽  
WG Murphy
Keyword(s):  
Platelet Aggregation ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Disease Process ◽  
The Other ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Thrombocytopenic Purpura ◽  
Induced Aggregation

Many patients with thrombotic thrombocytopenic purpura (TTP) have a platelet aggregating factor in their serum that may be pathologically linked with the disease process. To help characterize the type of platelet aggregation and platelet release induced by the sera from seven TTP patients, we measured the ability of a variety of inhibitors of platelet function as well as the ability of monoclonal antibodies (MoAbs) against platelet glycoproteins to inhibit TTP sera-induced platelet aggregation and release. These results were compared with the ability of the same inhibitors to block platelet aggregation induced by ristocetin, collagen, ADP, thrombin, and IgG-immune complexes. Monoclonal antibody directed against platelet glycoprotein Ib totally inhibited ristocetin-induced aggregation and release but had no effect on aggregation and release induced by the TTP sera or by any of the other platelet agonists. However, the MoAb against glycoproteins IIb/IIIa inhibited aggregation and release caused by TTP sera as well as by collagen, thrombin, and ADP but had no effect on aggregation and release induced by ristocetin. The aggregating activity could be abolished by heparin but not by the serine protease inhibitor PMSF (1 mmol/L). And although monomeric human IgG and purified Fc fragments of IgG inhibited IgG-immune complex-induced aggregation and release, they had no effect on TTP sera-induced aggregation and release nor on aggregation and release induced by any of the other agonists. Consistent with these in vitro studies showing no effect of IgG were the in vivo observations that intravenous (IV) IgG was without effect when administered to three patients with TTP. This study indicates that although a von Willebrand factor (vWF)-rich preparation of cryoprecipitate enhances the in vitro platelet aggregation and release caused by sera from the seven TTP patients we studied, the pathway of aggregation and release is not via platelet glycoprotein Ib. Also the aggregating factor of TTP sera is not neutralized in vitro or in vivo by IgG.

scholarly journals Exome Sequencing Identifies Glycosylation Defects As a Probable Cause of Immune Thrombotic Thrombocytopenic Purpura

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 217-217
Author(s):  
Felipe Massicano ◽  
Elizabeth M. Staley ◽  
Konstantine Halkidis ◽  
Nicole K. Kocher ◽  
Lance A. Williams ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Potential Contribution ◽  
Severe Thrombocytopenia ◽  
Adamts13 Activity ◽  
Genomic Alterations ◽  
Autoantibody Production ◽  
Thrombocytopenic Purpura ◽  
Long Term Outcome ◽  
Clinical Presentations

Background: Immune thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal syndrome, resulting primarily from autoantibodies against ADAMTS13. However, the mechanism underlying the autoantibody formation and the contribution of other genomic alterations to the pathogenesis of iTTP are largely unknown. Methods: Whole exome sequencing (WES) and bioinformatic analyses were performed to determine the genetic variations in 40 patients with iTTP who had ADAMTS13 activity &lt;10 IU/dL and a positive inhibitor or an elevated anti-ADAMTS13 IgG in concordance with clinical presentations of severe thrombocytopenia and microangiopathic hemolytic anemia with various degrees of organ injury. WES was also performed at the same time in fifteen age-, gender-, and ethnicity- matched individuals who did not have a history of iTTP or other hematological disorders as controls. Results: WES identified variants or mutations in the genes involving in glycosylation, including O-linked glycosylation, to be the major pathway affected in patients with iTTP. We propose that the altered glycosylation may be responsible for the development of autoantibodies against ADAMTS13 which impair the proteolytic cleavage of von Willebrand factor, accelerate the clearance of ADAMTS13 from circulation, and result in severe thrombocytopenia platelets in patients with iTTP. We also identified defects in ankyrin repeat containing protein ANKRD36C, a protein with hitherto unknown function, as the most statistically significant genomic alterations associated with iTTP (p &lt; 10-5). Moreover, candidate gene analysis revealed that various genes involving in hemostasis, complement activation, platelet function and signaling pathway, and inflammation were all affected in patients with iTTP, which may contribute to the onset, progress, severity, and long-term outcome of iTTP. Finally, we also identified two patient subgroups where the disease mechanism might be different. Conclusion: Our findings provide novel insight into the pathogenic mechanism underlying ADAMTS13 autoantibody production and the potential contribution of other genetic abnormalities in modifying the iTTP clinical presentations in the individuals with severe deficiency of plasma ADAMTS13 activity. Disclosures Zheng: Alexion: Speakers Bureau; Ablynx/Sanofi: Consultancy, Speakers Bureau; Shire/Takeda: Research Funding; Clotsolution: Other: Co-Founder.

scholarly journals Thrombotic Thrombocytopenic Purpura in Interferon Beta-1a-Treated Patient Diagnosed with Relapsing-Remitting Multiple Sclerosis: A Case Report

Life ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 80
Author(s):  
Cristina-Florentina Plesa ◽  
Diana Maria Chitimus ◽  
Carmen Adella Sirbu ◽  
Monica Marilena Țânțu ◽  
Minerva Claudia Ghinescu ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Thrombotic Microangiopathy ◽  
Interferon Beta ◽  
Thrombocytopenic Purpura ◽  
Beta Interferon ◽  
Relapsing Remitting ◽  
Remitting Multiple Sclerosis ◽  
Multiple Sclerosis Patients ◽  
Relapsing Remitting Multiple Sclerosis

Background: Secondary thrombotic thrombocytopenic purpura (TTP) due to interferon beta-1a intramuscular (im) treatment is an uncommon adverse effect with only a few cases in multiple sclerosis patients reported worldwide. TTP together with haemolytic uremic syndrome (HUS) are classic forms of thrombotic microangiopathy, characterized by small-vessel platelet micro-thrombi that manifest clinically in a similar manner. Most common signs and symptoms include bruises and ecchymosis, neurologic symptoms and renal impairment. Interferon beta-1a represents one of the first-line therapies for relapsing-remitting multiple sclerosis due to its accessibility and efficacy. Case presentation: A 36-year-old woman who was previously diagnosed with relapsing-remitting multiple sclerosis had received weekly intramuscular injections with beta-interferon-1a (Avonex 30 mcg). After 9 months of treatment, she presented bruises and ecchymosis on her limbs and torso, epistaxis, gingival bleeding aggravated within 48 h and a persistent headache that was non-responsive to common analgesics. Haematology tests revealed typical results for thrombotic microangiopathy, including severe thrombocytopenia (4000/mm3) and microangiopathic haemolytic anaemia with frequent schistocytes on the peripheral blood smear. Once the beta-interferon administration was ceased and upon the initiation of methylprednisolone, the symptoms remitted. Conclusions: In this case study, we portrayed the particular association between the remission phase of multiple sclerosis and the violent onset of interferon-induced thrombotic thrombocytopenic purpura.

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