Platelet-delivered ADAMTS13 inhibits arterial thrombosis and prevents thrombotic thrombocytopenic purpura in murine models

Pickens, Brandy; Mao, Yingying; Li, Dengju; Siegel, Don L.; Poncz, Mortimer; Cines, Douglas B.; Zheng, X. Long

doi:10.1182/blood-2014-07-587139

Cited by 31 publications

(35 citation statements)

References 48 publications

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“…Recently, however, transgenic ADAMTS13 expressed in platelets was demonstrated to prevent both congenital and acquired TTP. 15 Although a truly elegant approach, packing ADAMTS13 into platelets is not directly translatable toward patients because this technique is challenging if not impossible at the moment. Plasminogen activation has been suggested as a possible bypass for ADAMTS13 deficiency because plasmin cleavage of VWF reduced the formation of VWF-rich microthrombi in Adamts13 −/− mice in which TTP-like symptoms had been induced with rVWF.…”

Section: Discussionmentioning

confidence: 99%

Potential for Recombinant ADAMTS13 as an Effective Therapy for Acquired Thrombotic Thrombocytopenic Purpura

Tersteeg

Schiviz

Meyer

et al. 2015

ATVB

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Objective-The metalloprotease ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) regulates the size of von Willebrand factor multimers. A deficiency in ADAMTS13 activity is associated with the life-threatening disease thrombotic thrombocytopenic purpura (TTP). The vast majority of patients have acquired TTP, where circulating anti-ADAMTS13 autoantibodies are causative for the decreased ADAMTS13 activity. Current treatment consists of plasma exchange, but improved therapies are highly warranted. Approach and Results-We have developed a new rat model mimicking various aspects of acquired TTP to investigate the therapeutic efficacy of human recombinant ADAMTS13. A polyclonal antibody against ADAMTS13 completely blocked endogenous rat ADAMTS13 activity in Sprague-Dawley rats. When TTP was triggered using recombinant von Willebrand factor, the animals displayed severe TTP-like symptoms, such as thrombocytopenia, hemolytic anemia, and von Willebrand factor-rich thrombi in the kidneys and brain. Subsequent injection of 400, 800, or 1600 U/kg recombinant ADAMTS13 prevented full development of these symptoms. Analysis of plasma samples confirmed that recombinant ADAMTS13 was able to override circulating anti-ADAMTS13 inhibitory antibodies, resulting in restoration of ADAMTS13 activity and degradation of ultralarge von Willebrand factor multimers. Conclusions-Recombinant ADAMTS13 was shown to be effective in averting severe acquired TTP-like symptoms in rats and holds promising value for the treatment of this severe and life-threatening disease in humans. rADAMTS13 therapy seems to be a promising treatment opportunity for this patient group. In the presented study, we developed a rat model mimicking various aspects of acquired TTP, with which we further explored the feasibility of rAD-AMTS13 treatment in acquired TTP. Materials and MethodsMaterials and Methods are available in the online-only Data Supplement. Results Establishing a Rat Model Resembling Acquired TTPFirst, rats were injected with polyclonal anti-ADAMTS13 antibodies (650 U/kg) to block endogenous rat ADAMTS13 activity and to establish a robust inhibitor titer of ≈10 BU/ mL. Then, animals were administered 2000 U/kg recombinant VWF (rVWF) to trigger TTP symptoms.11 Control animals received either control IgG instead of anti-ADAMTS13 antibodies or saline instead of rVWF. Animals were followed for 24 h, and blood samples were analyzed after 3 and 24 h. The normal platelet count at baseline was 650±177×10 3 platelets/μL blood ( Figure 1A). Rats injected with anti-ADAMTS13 antibodies and triggered with rVWF developed thrombocytopenia, with a platelet count of 427±111×10 3 /μL after 3 h and 218±40×10 3 /μL after 24 h ( Figure 1A). Neither injection of anti-ADAMTS13 antibodies without additional rVWF nor injection of control IgG with rVWF resulted in thrombocytopenia (652±146×10 3 /μL and 766±63×10 3 /μL after 24 h, respectively; Figure 1A). Hemoglobin levels also decreased significantly after 24 h when rats developed TTP ...

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Section: Discussionmentioning

confidence: 99%

Potential for Recombinant ADAMTS13 as an Effective Therapy for Acquired Thrombotic Thrombocytopenic Purpura

Tersteeg

Schiviz

Meyer

et al. 2015

ATVB

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“…Murine recombinant VWF (mVWF) was expressed in HEK293 cells and purified according to the protocol described elsewhere. 29 Human VWF was purified from normal human plasma as described previously. 30 …”

Section: Methodsmentioning

confidence: 99%

Therapeutic efficacy of the platelet glycoprotein Ib antagonist anfibatide in murine models of thrombotic thrombocytopenic purpura

et al. 2016

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Thrombotic thrombocytopenic purpura (TTP), a potentially fatal blood clot disorder, is primarily caused by severe deficiency of plasma ADAMTS13 activity resulting from acquired autoantibodies. Plasma exchange is the only effective initial therapy. However, the high mortality rate and the complications associated with plasma exchange therapy remain a major concern. To address unmet clinical needs, therapeutic efficacies of anfibatide, a snake venom-derived platelet glycoprotein Ib antagonist, in murine models of spontaneous thrombocytopenia and shigatoxin-induced TTP were determined. A light scattering platelet aggregometry, microfluidic shear-based assay, and murine models of TTP were used in the study. We showed that purified anfibatide inhibits ristocetin- or botrocetin-induced human or murine platelet agglutination in the presence of von Willebrand factor in a concentration-dependent manner. Anfibatide could also dramatically inhibit the adhesion and aggregation of murine and human platelets on a collagen surface under arterial shear stress, in the presence or absence of plasma ADAMTS13 activity. Most importantly, we demonstrated that an intraperitoneal administration of anfibatide at the dose of 60 ng/g body weight twice daily mitigated spontaneous thrombocytopenia and prevented shigatoxin-induced TTP in Adamts13−/− and disease-susceptible mice (CAST/Ei strain). Thus, we conclude that anfibatide, when administered at the optimal dosage, route, and interval, is efficacious in treating spontaneous and bacterial shigatoxin-induced TTP in the murine models. Our findings may provide the basis for further development of anfibatide for the treatment of acute TTP in humans.

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“…Conjugation with polymers (e.g., polyethylene glycol, PEG)[1], loading within synthetic carriers (liposomes, polymers, nanoparticles, etc)[2], coupling with natural carrier molecules[3], and other approaches have been devised to reduce elimination and optimize delivery of chemical drugs, biotherapeutics, and imaging probes. In addition to these “artificial” delivery systems, blood elements (red blood cells[4], white blood cells[5], platelets[6]) have special biological features that might enable them to serve as “smart” natural carriers for vascular drug delivery.…”

Section: Introductionmentioning

confidence: 99%

Erythrocytes as Carriers for Drug Delivery in Blood Transfusion and Beyond

Villa

Cines

Siegel

et al. 2017

Transfusion Medicine Reviews

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Red blood cells (RBCs) are innate carriers that can also be engineered to improve the pharmacokinetics and pharmacodynamics of many drugs, particularly bio-therapeutics. Successful loading of drugs, both internally and on the external surface of RBCs, has been demonstrated for many drugs including anti-inflammatory, anti-microbial, and anti-thrombotic agents. Methods for internal loading of drugs within RBCs are now entering clinical use. While internal loading can result in membrane disruption that may compromise biocompatibility, surface loading using either affinity or chemical ligands offers a diverse set of approaches for the production of RBC drug carriers. A wide range of surface determinants is potentially available for this approach, although there remains a need to characterize the effects of coupling agents to these surface proteins. Somewhat surprisingly, recent data also suggest that red cell mediated delivery may confer tolerogenic immune effects. Questions remaining before widespread application of these technologies include determining the optimal loading protocol, source of RBCs, and production logistics, as well as addressing regulatory hurdles. RBC drug carriers, after many decades of progress, are now poised to enter the clinic and broaden the potential application of RBCs in blood transfusion.

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Platelet-delivered ADAMTS13 inhibits arterial thrombosis and prevents thrombotic thrombocytopenic purpura in murine models

Abstract: Key Points Platelet-delivered ADAMTS13 inhibits arterial thrombosis after vascular injury. Platelet-delivered ADAMTS13 also prevents thrombotic thrombocytopenic purpura.

Cited by 31 publications

References 48 publications

Potential for Recombinant ADAMTS13 as an Effective Therapy for Acquired Thrombotic Thrombocytopenic Purpura

Potential for Recombinant ADAMTS13 as an Effective Therapy for Acquired Thrombotic Thrombocytopenic Purpura

Therapeutic efficacy of the platelet glycoprotein Ib antagonist anfibatide in murine models of thrombotic thrombocytopenic purpura

Erythrocytes as Carriers for Drug Delivery in Blood Transfusion and Beyond

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