scholarly journals The combined roles of ADAMTS13 and VWF in murine models of TTP, endotoxemia, and thrombosis

Blood ◽  
2008 ◽  
Vol 111 (7) ◽  
pp. 3452-3457 ◽  
Author(s):  
Anil K. Chauhan ◽  
Meghan T. Walsh ◽  
Guojing Zhu ◽  
David Ginsburg ◽  
Denisa D. Wagner ◽  
...  
Keyword(s):  
Genetic Background ◽  
Murine Models ◽  
Prothrombotic State ◽  
Complete Protection ◽  
Absolute Requirement ◽  
Adamts13 Deficiency ◽  
Normal Hemostasis ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Deficient Mice

Abstract Ultralarge von Willebrand factor (UL-VWF) multimers are thought to play a central role in pathogenesis of the disease thrombotic thrombocytopenic purpura (TTP); however, experimental evidence in support of this hypothesis has been difficult to establish. Therefore, to examine directly the requirement for VWF in TTP pathogenesis, we generated ADAMTS13-deficient mice on a TTP-susceptible genetic background that were also either haploinsufficient (Vwf+/−) or completely deficient (Vwf−/−) in VWF. Absence of VWF resulted in complete protection from shigatoxin (Stx)–induced thrombocytopenia, demonstrating an absolute requirement for VWF in this model (Stx has been shown previously to trigger TTP in ADAMTS13-deficient mice). We next investigated the requirements for ADAMTS13 and VWF in a murine model of endotoxemia. Unlike Stx-induced TTP findings, LPS-induced thrombocytopenia and mortality were not affected by either VWF or ADAMTS13 deficiency, suggesting divergent mechanisms of thrombocytopenia between these 2 disorders. Finally, we show that VWF deficiency abrogates the ADAMTS13-deficient prothrombotic state, suggesting VWF as the only relevant ADAMTS13 substrate under these conditions. Together, these findings shed new light on the potential roles played by ADAMTS13 and VWF in TTP, endotoxemia, and normal hemostasis.

A Threshold Level of Von Willebrand Factor Is Required for Disease Pathogenesis in a Mouse Model of TTP.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 177-177
Author(s):  
David G. Motto ◽  
Guojing Zhu ◽  
Denisa D. Wagner ◽  
David Ginsburg
Keyword(s):  
Mouse Model ◽  
Von Willebrand Factor ◽  
Genetic Background ◽  
Critical Role ◽  
Threshold Level ◽  
Bacterial Agent ◽  
Absolute Requirement ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Deficient Mice

Abstract Thrombotic Thrombocytopenic Purpura (TTP) is a life threatening systemic illness associated with inherited or acquired deficiency of the ADAMTS13 metalloprotease. ADAMTS13 deficiency results in the appearance of ultra-large multimers of von Willebrand Factor (UL-VWF) in the circulation, which are thought to play a central role in the formation of the platelet-rich thrombi which are the pathological hallmark of this disease. Despite the critical role postulated for VWF in TTP pathogenesis, direct experimental evidence in support of this hypothesis is lacking. Recently we demonstrated that a TTP-like syndrome can be induced in ADAMTS13-deficient mice of a mixed CASA/Rk genetic background (Adamts13CASA−/−) by the bacterial agent shigatoxin. As pure CASA/Rk mice exhibit VWF levels 5 to 10-fold higher than most of the common strains of laboratory mice, we hypothesized that increased plasma VWF levels in the Adamts13CASA−/− mice (which ranged from 200–600% of C57BL/6) were responsible for their increased TTP susceptibility. Surprisingly however, plasma VWF levels did not correlate with the degree of thrombocytopenia or hemolytic anemia induced in Adamts13CASA−/− mice by shigatoxin challenge, with mice inheriting the lowest VWF levels having TTP pathology equal to those inheriting the highest levels. To further examine the requirement for VWF in TTP pathogenesis, we generated ADAMTS13-deficient mice on a susceptible CASA/Rk genetic background that were also either haploinsufficient (Vwf+/−) or completely deficient (Vwf−/−) in VWF. Absolute deficiency of VWF resulted in complete protection from shigatoxin-induced thrombocytopenia. However, thrombocytopenia was consistently observed in Vwf+/− mice similar to that previously reported in Adamts13CASA−/− mice with wild-type VWF. Importantly, again no correlation was observed between VWF level and degree of thrombocytopenia among the ADAMTS13-deficient mice that were Vwf haploinsufficient (Vwf+/−), confirming our previous observation. In summary, we now have demonstrated an absolute requirement for VWF in the pathogenesis of TTP in this mouse model system. Together with the observations that increasing VWF levels do not correlate with increasing TTP pathology, these results suggest that a threshold level of VWF is required for induction of TTP, but that further increases of VWF level do not result in worsening disease. Though these findings remain to be confirmed in humans, our data suggest that the wide variation in plasma VWF levels in the human population will not be a significant determinant of TTP susceptibility or disease severity.

A common origin of the 4143insA ADAMTS13 mutation

2006 ◽  
Vol 96 (07) ◽  
pp. 3-6 ◽  
Author(s):  
Johanna A. Hovinga ◽  
Tim Becker ◽  
Ulrich Budde ◽  
Diana Karpman ◽  
Wolfgang Brockhaus ◽  
...  
Keyword(s):  
Genetic Background ◽  
Initial Report ◽  
The Czech Republic ◽  
European Origin ◽  
Geographic Concentration ◽  
Central European ◽  
Adamts13 Deficiency ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Deficient Activity

SummarySeverely deficient activity of the von Willebrand Factor (VWF) cleaving metalloprotease,ADAMTS13, is associated with thrombotic thrombocytopenic purpura (TTP).The mutation spectrum of ADAMTS13 is rather heterogeneous,and numerous mutations spread across the gene have been described in association with congenital TTP. The 4143insA mutation is unusual with respect to its geographic concentration. Following the initial report from Germany in which the 4143insA mutation was detected in four apparently unrelated families, we have now identified this mutation in a further eleven patients from Norway, Sweden, Poland, Germany, the Czech Republic and Australia. Confirmation that the Australian patient is of German ancestry, together with the Northern and Central European origin of most of the other patients, suggests that the 4143insA mutation has a common genetic background. We established ADAMTS13 haplotypes by analyzing 17 polymorphic intragenic markers. The haplotypes linked to 4143insA were identical in all informative families. Three novel candidate mutations, C347S, P671L and R1060W, as well as the known mutation R507Q, were also identified during the course of the study. We conclude that 4143insA has a common genetic background and is frequent among patients with hereditary ADAMTS13 deficiency in Northern and Central European countries.

ADAMTS13 turns 3

Blood ◽  
2005 ◽  
Vol 106 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Gallia G. Levy ◽  
David G. Motto ◽  
David Ginsburg
Keyword(s):  
Research Effort ◽  
Adamts13 Activity ◽  
Hematologic Disease ◽  
Thrombocytopenic Purpura ◽  
Adamts13 Deficiency ◽  
Normal Hemostasis ◽  
Von Willebrand ◽  
Willebrand Factor

It has now been 3 years since the von Willebrand factor (VWF)–cleaving protease implicated in thrombocytopenic purpura (TTP) pathogenesis was identified as ADAMTS13 (adisintegrin-like and metalloprotease with thrombospondin type 1 motif 13). More than 50 ADAMTS13 mutations resulting in familial TTP have been reported. Considerable progress has also been realized toward understanding the role of ADAMTS13 in normal hemostasis, as well as the mechanisms by which ADAMTS13 deficiency contributes to TTP pathogenesis. Measurement of ADAMTS13 activity in TTP and other pathologic conditions also remains a focus of a substantial clinical research effort. Building on these studies, continued investigation of ADAMTS13 and VWF holds considerable promise for advancing the understanding of TTP pathogenesis and should lead to improved diagnosis and treatment for this important hematologic disease.

Shigatoxin Triggers Thrombotic Thrombocytopenic Purpura in Genetically Susceptible ADAMTS13-Deficient Mice.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 723-723 ◽  
Author(s):  
David G. Motto ◽  
Anil K. Chauhan ◽  
Guojing Zhu ◽  
Jonathon Homeister ◽  
Colin B. Lamb ◽  
...  
Keyword(s):  
Key Factors ◽  
Multiple Organs ◽  
Modifying Factors ◽  
Life Threatening ◽  
Uremic Syndrome ◽  
Adamts13 Deficiency ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Deficient Mice ◽  
Insight Into

Abstract The life threatening disease TTP is associated with ultra-large von Willebrand Factor multimers (UL-VWF) in the circulation due to inherited or acquired deficiency of the ADAMTS13 metalloprotease. Here we show that ADAMTS13-deficient mice generated by gene targeting are viable and exhibit normal survival through 2 years of age. Despite the absence of VWF-cleaving protease activity (<1% of normal), wild-type and ADAMTS13-deficient plasma exhibit identical VWF multimer distributions, and Adamts13−/− mice develop spontaneous TTP at an extremely low rate (2 cases out of 358 mice). However, intravital microscopy demonstrated that VWF-mediated platelet-endothelial interactions are significantly prolonged in Adamts13−/− mice. These observations suggested that additional environmental triggers and/or genetic modifying factors may be required to bring about TTP in the setting of ADAMTS13 deficiency. To address the effect of VWF level on development of TTP, Adamts13−/− mice were crossed to mice of the CASA/Rk strain which exhibit markedly elevated plasma VWF levels. Resulting CASA/Adamts13−/− mice demonstrated plasma VWF ranging from 150% to 600% of C57BL/6 controls, and we found that 21% of these mice were thrombocytopenic at baseline (vs. 0% of controls). Introduction of the CASA/Rk genetic background also resulted in the appearance of UL-VWF in CASA/Adamts13−/− mice, further prolonged VWF-mediated platelet-endothelial cell interactions, increased the rate of spontaneous TTP, and markedly decreased survival. Challenge of CASA/Adamts13−/− mice with shigatoxin (derived from bacterial pathogens associated with the related human disease hemolytic uremic syndrome) resulted in a striking syndrome closely resembling human TTP, with thrombocytopenia, profound microangiopathic hemolytic anemia, and platelet- and VWF-thrombi seen in multiple organs. Surprisingly, we observed no correlation between plasma VWF level and severity of TTP, implying the existence of TTP-modifying genes distinct from VWF. Our laboratory is pursuing the identification of these genes which may provide insight into the pathogenesis and treatment of TTP in humans. Finally, our data also suggest that microbial-derived toxins, or possibly other sources of endothelial injury, may be among the key factors required to trigger acute TTP in the setting of ADAMTS13 deficiency.

The Relationship Between The Multimeric Structure Of F VIII-VWF And The Facilitation Of Platelet Adhesion To Human Subendothelium (Von Willebrand Factor Activity VWF-A)

1981 ◽  
Author(s):  
Jan J Sixma ◽  
Kjell S Sakariassen ◽  
Piet A Bolhuis
Keyword(s):  
High Purity ◽  
Human Platelets ◽  
Gel Chromatography ◽  
Absolute Requirement ◽  
Mild Reduction ◽  
Agarose Electrophoresis ◽  
Von Willebrand ◽  
The Relationship ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

The relation between the VWF-A of F VIII-VWF and its multimeric structure was studied in an annular perfusion chamber according to Baumgartner, with a steady flow system. 51Cr-labelled aspirin treated human platelets and human post mortem renal arteries were employed. F VIII-VWF was purified from cryoprecipitate by agarose gel chromatography and radiolabelled by the lactoperoxydase method. The multimeric distribution was determined by SDS-agarose electrophoresis. Five different commercial high purity concentrates contained multimers between 0.5 and 3.5 x 106 mol wt. None of these concentrates had VWF-A at ristocetin cofactor activities (RIC0F-A) of 1.0 u/ml. A low potency concentrate with mul- timers in the same mol wt range had normal VWF-A. Mild reduction (dithioerythritol-DTE ≤ 2mM) caused a shift in , mol wt range from 3.0 - 20.0 × 106 towards 0.5 - 2.0 × 106 with little decrease in RIC0F-A and VWF-A. Reduction with 10 mM DTE produced multimers of 1.5 and 0.5 × 106 without RICOF-A and VWF-A, but binding normally to the vessel wall. The void volume peak of 125I-VIII-VWF was rechromatographed on Sepharose-2B and arbitrarily divided in fractions A: mol wt 8,0 - 18.0 × 106 ;B: mol wt 4.5 - 11.0 × 106 ; and C: mol wt 2.5 - 6.5 × 106 . Binding of 125I-VIII-VWF to the subendothelium was highest for A, intermediate for B and lowest for C. Correction for mean mol wt showed that almost equal numbers of molecules bound from all three fractions. When the quantity of bound VIII-VWF was thus expressed, all fractions had a similar relative VWF-A.These data indicate that high purity concentrates do not correct the bleeding time at normal RICOF-levels, because they lack VWF-A. Multimers of high mol wt normally carry both RICOF-A and VWF-A, but the high mol wt is no absolute requirement. These data are in agreement with the notion that VWF-A resides on a specific polypeptide chain in the molecule.

Fibrinogen is required for maintenance of platelet intracellular and cell-surface P-selectin expression

Blood ◽  
2009 ◽  
Vol 114 (2) ◽  
pp. 425-436 ◽  
Author(s):  
Hong Yang ◽  
Sean Lang ◽  
Zhimin Zhai ◽  
Ling Li ◽  
Walter H. A. Kahr ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Surface ◽  
Human Fibrinogen ◽  
C Terminus ◽  
Β3 Integrin ◽  
Von Willebrand ◽  
Selectin Binding ◽  
Willebrand Factor ◽  
Deficient Mice ◽  
Granule Release

Abstract Platelet P-selectin plays important roles in inflammation and contributes to thrombosis and hemostasis. Although it has been reported that von Willebrand factor (VWF) affects P-selectin expression on endothelial cells, little information is available regarding regulation of platelet P-selectin expression. Here, we first observed that P-selectin expression was significantly decreased on platelets of fibrinogen and VWF double-deficient mice. Subsequently, we identified this was due to fibrinogen deficiency. Impaired P-selectin expression on fibrinogen-deficient platelets was further confirmed in human hypofibrinogenemic patients. We demonstrated that this impairment is unlikely due to excessive P-selectin shedding, deficient fibrinogen-mediated cell surface P-selectin binding, or impaired platelet granule release, but rather is due to decreased platelet P-selectin content. Fibrinogen transfusion completely recovered this impairment in fibrinogen-deficient (Fg−/−) mice, and engagement of the C-terminus of the fibrinogen γ chain with β3 integrin was required for this process. Furthermore, Fg−/− platelets significantly increased P-selectin expression following transfusion into β3 integrin–deficient mice and when cultured with fibrinogen. These data suggest fibrinogen may play important roles in inflammation, thrombosis, and hemostasis via enhancement of platelet P-selectin expression. Since human fibrinogen levels vary significantly in normal and diseased populations, P-selectin as an activation marker on platelets should be used with caution.

scholarly journals The Influence of Inflammation on Fibrinogen Turnover and Redistribution of the Hemostatic Balance to a Prothrombotic State in High On-Treatment Platelet Reactivity-Dual Poor Responder (HTPR-DPR) Patients

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Grzegorz Biolik ◽  
Dariusz Gajniak ◽  
Maciej Kubicz ◽  
Damian Ziaja ◽  
Krzysztof Ziaja ◽  
...  
Keyword(s):  
Inflammatory Process ◽  
Platelet Reactivity ◽  
Limb Ischemia ◽  
Poor Responder ◽  
Prothrombotic State ◽  
High Concentration ◽  
Normal Range ◽  
Chronic Inflammatory Process ◽  
Von Willebrand ◽  
Willebrand Factor

Knowledge about the influence of inflammation on platelet function and relocation of hemostatic balance to hypercoagulable state is still unclear. We compared two groups of patients who suffer from acute vs. chronic inflammatory process and additionally present high on-treatment platelet reactivity-dual platelet resistance. We did not found any differences in platelet aggregation between both investigated groups, but patients who suffer from chronic inflammation presented stronger relocation of the hemostatic balance to the hypercoagulability. A high concentration of prothrombin fragment F1+2 together with higher activity of von Willebrand factor in critical limb ischemia shows more exaggerated fibrinogen turnover although the blood concentration of this factor was in normal range. We concluded that high on-treatment platelet reactivity-dual platelet resistance and intensified inflammation are linked with elevated platelet and fibrinogen turnover to counteract proper hemostatic balance in favor of a prothrombotic state.

scholarly journals Pathophysiology of thrombotic thrombocytopenic purpura

Blood ◽  
2017 ◽  
Vol 130 (10) ◽  
pp. 1181-1188 ◽  
Author(s):  
J. Evan Sadler
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Tissue Injury ◽  
Preventive Therapy ◽  
Neurological Deficits ◽  
Autoantibody Production ◽  
Thrombocytopenic Purpura ◽  
Adamts13 Deficiency ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The discovery of a disintegrin-like and metalloproteinase with thrombospondin type 1 motif, member 13 (ADAMTS13) revolutionized our approach to thrombotic thrombocytopenic purpura (TTP). Inherited or acquired ADAMTS13 deficiency allows the unrestrained growth of microthrombi that are composed of von Willebrand factor and platelets, which account for the thrombocytopenia, hemolytic anemia, schistocytes, and tissue injury that characterize TTP. Most patients with acquired TTP respond to a combination of plasma exchange and rituximab, but some die or acquire irreversible neurological deficits before they can respond, and relapses can occur unpredictably. However, knowledge of the pathophysiology of TTP has inspired new ways to prevent early deaths by targeting autoantibody production, replenishing ADAMTS13, and blocking microvascular thrombosis despite persistent ADAMTS13 deficiency. In addition, monitoring ADAMTS13 has the potential to identify patients who are at risk of relapse in time for preventive therapy.

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