Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Blood Adv ; 5(17): 3478-3491, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34505883

RESUMO

Trauma-induced organ failure is characterized by endothelial dysfunction. The aim of this study was to investigate the role of von Willebrand factor (VWF) and its cleaving enzyme, ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motifs, member 13) in the occurrence of endothelial permeability and organ failure in trauma. In an observational study in a level-1 trauma center, 169 adult trauma patients with clinical signs of shock and/or severe injuries were included. Trauma was associated with low ADAMTS13 and high VWF antigen levels, thus generating an imbalance of ADAMTS13 to VWF. Patients who developed organ failure (23%) had greater ADAMTS13-to-VWF imbalances, persistently lower platelet counts, and elevated levels of high-molecular-weight VWF multimers compared with those without organ failure, suggesting microthrombi formation. To investigate the effect of replenishing low ADAMTS13 levels on endothelial permeability and organ failure using either recombinant human ADAMTS13 (rhADAMTS13) or plasma transfusion, a rat model of trauma-induced shock and transfusion was used. Rats in traumatic hemorrhagic shock were randomized to receive crystalloids, crystalloids supplemented with rhADAMTS13, or plasma transfusion. A 70-kDa fluorescein isothiocyanate-labeled dextran was injected to determine endothelial leakage. Additionally, organs were histologically assessed. Both plasma transfusion and rhADAMTS13 were associated with a reduction in pulmonary endothelial permeability and organ injury when compared with resuscitation with crystalloids, but only rhADAMTS13 resulted in significant improvement of a trauma-induced decline in ADAMTS13 levels. We conclude that rhADAMTS13 and plasma transfusion can reduce organ failure following trauma. These findings implicate the ADAMTS13-VWF axis in the pathogenesis of organ failure.


Assuntos
Trombose , Fator de von Willebrand , Proteína ADAMTS13 , Animais , Transfusão de Componentes Sanguíneos , Humanos , Plasma , Ratos
2.
J Thromb Haemost ; 19(9): 2193-2198, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34219357

RESUMO

BACKGROUND: Critically ill patients with coronavirus disease 2019 (COVID-19) are prone to developing macrothrombosis and microthrombosis. COVID-19 has been reported to be rarely associated with thrombotic microangiopathies. A disintegrin and metalloprotease with thrombospondin type I repeats, member 13 (ADAMTS13) severe deficiency, the hallmark of thrombotic thrombocytopenic purpura (TTP), induces the formation of platelet, unusually large von Willebrand factor (VWF) multimer microthrombi. In immune-mediated TTP, ADAMTS13 adopts specifically an open conformation. The VWF/ADAMTS13 couple may contribute to the microthrombi formation in pulmonary alveolar capillaries in COVID-19. OBJECTIVE: To investigate clinical features, hemostatic laboratory parameters, VWF/ADAMTS13 axis, and ADAMTS13 conformation in critically ill COVID-19 patients at admission. METHODS: Fifty three critically ill COVID-19 patients were enrolled between March 18 and May 9 2020 in a monocentric hospital. RESULTS: The median age was 59 years and the male-to-female ratio was 2.8/1. We reported seven pulmonary embolisms and 15 deaths. Biological investigations showed increased fibrinogen and factor V levels, and strongly increased D-dimers correlated with mortality. No patient presented severe thrombocytopenia nor microangiopathic hemolytic anemia. An imbalance between high VWF antigen levels and normal or slightly decreased ADAMTS13 activity levels (strongly elevated VWF/ADAMTS13 ratio) was correlated with mortality. Three patients had a partial quantitative deficiency in ADAMTS13. We also reported a closed conformation of ADAMTS13 in all patients, reinforcing the specificity of an open conformation of ADAMTS13 as a hallmark of TTP. CONCLUSION: We suggest that slightly decreased or normal ADAMTS13 activity and highly elevated VWF are rather biomarkers reflecting both the strong inflammation and the endothelial damage rather than drivers of the thrombotic process of COVID-19.


Assuntos
COVID-19 , Púrpura Trombocitopênica Trombótica , Proteína ADAMTS13 , Biomarcadores , Estado Terminal , Feminino , Humanos , Inflamação , Masculino , Pessoa de Meia-Idade , Púrpura Trombocitopênica Trombótica/diagnóstico , SARS-CoV-2 , Fator de von Willebrand
3.
Vox Sang ; 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34196412

RESUMO

BACKGROUND AND OBJECTIVES: Red blood cell (RBC) transfusion is a frequently applied intervention in an intensive care unit. However, transfusion is associated with adverse outcomes including organ failure and thrombo-embolic events. Mechanisms of these effects are not known but may be related to activation of the endothelium or of the coagulation or inflammatory system. We hypothesized that a RBC transfusion in the critically ill would result in further activation of these systems. MATERIALS AND METHODS: In 74 non-bleeding critically ill patients receiving one RBC unit, markers of inflammation, endothelial cell activation and coagulation were measured before transfusion, at 1 h after transfusion and 24 h after transfusion. The impact of disease severity of the recipient on these changes was assessed by comparing septic and non-septic patients (according to sepsis-3 definition) and by correlation of biomarkers with the sequential organ failure assessment (SOFA) score. RESULTS: Levels of von Willebrand Factor (vWF), soluble ICAM-1, soluble thrombomodulin, fibrinogen and d-dimer were already high at baseline, whereas ADAMTS13 levels were low. VWF levels increased significantly 24 h after RBC transfusion (median 478% (338-597) vs. 526% (395-623), p = 0.009). The other biomarkers did not change significantly. Post transfusion change was not dependent on the presence of sepsis and was not correlated with SOFA score. CONCLUSION: RBC transfusion in critically ill patients was associated with an increase in circulating vWF levels, suggesting a further increase in activation of the endothelium, a finding that was independent of the presence of sepsis or organ injury level.

4.
J Thromb Haemost ; 19(9): 2248-2255, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33728786

RESUMO

BACKGROUND: Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is caused by inhibitory and/or clearing anti-ADAMTS-13 (A Disintegrin and Metalloprotease with ThromboSpondin type 1 repeats, member 13) autoantibodies. To determine the presence and total level of anti-ADAMTS-13 autoantibodies, commercial and in-house developed ELISAs are performed. However, different ELISA methods vary in relation to the presentation of recombinant (r)ADAMTS-13 and the detection method of the anti-ADAMTS-13 autoantibodies. Currently, the influence of those different approaches on anti-ADAMTS-13 autoantibody titers is not known. OBJECTIVES: To assess the influence of different ADAMTS-13 presentation- and autoantibody detection methods on anti-ADAMTS-13 autoantibody titers in ELISA. MATERIALS/METHODS: Anti-ADAMTS-13 autoantibody titers from 18 iTTP patients were determined using four different set-ups of anti-ADAMTS-13 autoantibody ELISAs. The ELISAs varied in the used presentation of rADAMTS-13 (directly coated full-length rADAMTS-13, directly coated rMDTCS and rT2C2, or antibody-captured full-length rADAMTS-13) and the detection antibodies (polyclonal anti-human IgG or monoclonal anti-human IgG1-4 antibodies). RESULTS: Strong correlations between the different anti-ADAMTS-13 autoantibody ELISA approaches were observed, when using polyclonal anti-human IgG detection antibodies recognizing all IgG subclasses similarly, independent of the method of rADAMTS-13 presentation. Anti-ADAMTS-13 autoantibody titers correlated less when using a mixture of monoclonal anti-human IgG1-4 , because not all IgG subclasses were recognized with similar affinities. CONCLUSION: Anti-ADAMTS-13 autoantibody levels using different methods of rADAMTS-13 presentation strongly correlate. However, the levels of anti-ADAMTS-13 autoantibodies are highly dependent on the detection antibody used, which should detect all IgG subclasses (IgG1-4 ) equally well.


Assuntos
Púrpura Trombocitopênica Trombótica , Trombospondina 1 , Proteína ADAMTS13 , Autoanticorpos , Ensaio de Imunoadsorção Enzimática , Humanos , Púrpura Trombocitopênica Trombótica/diagnóstico
5.
Anal Chem ; 92(20): 13880-13887, 2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-32929962

RESUMO

Autoantibodies are key biomarkers in clinical diagnosis of autoimmune diseases routinely detected by enzyme-linked immunosorbent assays (ELISAs). However, the complexity of these assays is limiting their use in routine diagnostics. Fiber optic-surface plasmon resonance (FO-SPR) can overcome these limitations, but improved surface chemistries are still needed to guarantee detection of autoantibodies in complex matrices. In this paper, we describe the development of an FO-SPR immunoassay for the detection of autoantibodies in plasma samples from immune-mediated thrombotic thrombocytopenic purpura (iTTP) patients. Hereto, hexahistidine-tagged recombinant ADAMTS13 (rADAMTS13-His6) was immobilized on nitrilotriacetic acid (NTA)-coated FO probes chelated by cobalt (Co(III)) and exposed to anti-ADAMTS13 autoantibodies. Initial studies were performed to optimize rADAMTS13-His6 immobilization and to confirm the specificity of the immunoassay for detection of anti-ADAMTS13 autoantibodies with FO-SPR. The performance of the immunoassay was then evaluated by comparing Co(III)- and nickel (Ni(II))-NTA stabilized surfaces, confirming the stable immobilization of the antigen in Co(III)-NTA-functionalized FO probes. A calibration curve was prepared with a dilution series of a cloned human anti-ADAMTS13 autoantibody in ADAMTS13-depleted plasma resulting in an average interassay coefficient of variation of 7.1% and a limit of detection of 0.24 ng/mL. Finally, the FO-SPR immunoassay was validated using seven iTTP patient plasma samples, resulting in an excellent correlation with an in-house-developed ELISA (r = 0.973). In summary, the specificity and high sensitivity in combination with a short time-to-result (2.5 h compared to 4-5 h for a regular ELISA) make the FO-SPR immunoassay a powerful assay for routine diagnosis of iTTP and with extension for any other autoimmune disease.


Assuntos
Autoanticorpos/sangue , Técnicas Biossensoriais/métodos , Cobre/química , Ácido Nitrilotriacético/química , Ressonância de Plasmônio de Superfície , Proteína ADAMTS13/química , Proteína ADAMTS13/genética , Proteína ADAMTS13/metabolismo , Tecnologia de Fibra Óptica , Histidina/genética , Histidina/metabolismo , Humanos , Proteínas Imobilizadas/química , Proteínas Imobilizadas/imunologia , Imunoensaio , Limite de Detecção , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Púrpura Trombocitopênica Trombótica/diagnóstico
6.
Blood ; 136(3): 353-361, 2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32356859

RESUMO

Recently, we showed that ADAMTS13 circulates in an open conformation during the acute phase of immune-mediated thrombotic thrombocytopenic purpura (iTTP). Although the cause of this conformational change remains elusive, ADAMTS13 is primarily closed in iTTP patients in remission with ADAMTS13 activity >50% and undetectable anti-ADAMTS13 autoantibodies, as well as after rituximab treatment, suggesting a role for anti-ADAMTS13 autoantibodies. Therefore, immunoglobulin G from 18 acute iTTP patients was purified and added to closed ADAMTS13 in healthy donor plasma. This resulted in open ADAMTS13 in 14 of 18 (78%) samples, proving that anti-ADAMTS13 autoantibodies can induce an open ADAMTS13 conformation. To further elucidate the conformation of ADAMTS13 in iTTP patients, we studied a novel iTTP patient cohort (n = 197) that also included plasma samples from iTTP patients in remission in whom ADAMTS13 activity was <50%. The open ADAMTS13 conformation was found during acute iTTP, as well as in patients in remission with ADAMTS13 activity <50% and in half of the patients with ADAMTS13 activity >50%, although free anti-ADAMTS13 autoantibodies were not always detected. Thus, open ADAMTS13 is a hallmark of acute iTTP, as well as a novel biomarker that can be used to detect subclinical iTTP in patients in remission. Finally, a long-term follow-up study in 1 iTTP patient showed that the open conformation precedes a substantial drop in ADAMTS13 activity. In conclusion, we have shown that anti-ADAMTS13 autoantibodies from iTTP patients induce an open ADAMTS13 conformation. Most importantly, an open ADAMTS13 conformation is a biomarker for subclinical iTTP and could become an important tool in TTP management.


Assuntos
Proteína ADAMTS13/sangue , Autoanticorpos/sangue , Púrpura Trombocitopênica Idiopática/sangue , Biomarcadores/sangue , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Conformação Proteica , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Rituximab/administração & dosagem
7.
J Thromb Haemost ; 18(4): 985-990, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31989742

RESUMO

BACKGROUND: The biological diagnosis of immune-mediated thrombotic thrombocytopenic purpura (iTTP) is based on determination of ADAMTS13 activity (<10%) and anti-ADAMTS13 autoantibodies. ADAMTS13 antigen levels are not routinely measured in iTTP patients, but studies have shown that antigen levels are a valuable prognostic factor. OBJECTIVES: To (a) report the validation of our in-house developed ADAMTS13 antigen enzyme-linked immunosorbent assay (ELISA) and determine ADAMTS13 antigen in a large cohort of healthy donor and iTTP patient plasma samples; and (b) to investigate whether ADAMTS13 antigen determination is not disturbed by the presence of anti-ADAMTS13 autoantibodies. METHODS: Our in-house ADAMTS13 antigen ELISA was validated in terms of sensitivity, repeatability, and reproducibility. ADAMTS13 antigen levels were determined in plasma samples from 423 healthy donors and 112 acute iTTP patients. Purified IgGs from iTTP patients were added to normal human plasma to determine whether anti-ADAMTS13 autoantibodies hampered ADAMTS13 antigen determination. RESULTS: Our in-house ADAMTS13 antigen ELISA has a detection limit of 3% and low intra-assay (coefficient of variation, %CV < 10%) and inter-assay (%CV < 18%) variability. ADAMTS13 antigen levels were significantly reduced (P < .0001) in acute iTTP patients (15 ± 18%) compared to healthy donors (101 ± 18%). The anti-ADAMTS13 autoantibodies in plasma of iTTP patients did not impede ADAMTS13 antigen determinations using our in-house ELISA. CONCLUSIONS: Our in-house ADAMT13 antigen ELISA is a powerful tool to correctly determine ADAMTS13 antigen levels in iTTP patients, which supports routine ADAMTS13 antigen measurements in these patients to have better insight into disease prognosis.


Assuntos
Púrpura Trombocitopênica Idiopática , Púrpura Trombocitopênica Trombótica , Proteína ADAMTS13 , Autoanticorpos , Ensaio de Imunoadsorção Enzimática , Humanos , Púrpura Trombocitopênica Trombótica/diagnóstico , Reprodutibilidade dos Testes
9.
Blood ; 129(8): 1030-1038, 2017 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-28011677

RESUMO

Thrombotic thrombocytopenic purpura (TTP) is a microangiopathic disorder diagnosed by thrombocytopenia and hemolytic anemia, associated with a deficiency in von Willebrand factor (VWF)-cleaving protease ADAMTS13. Current treatment is based on plasma infusion for congenital TTP, or plasma exchange, often in combination with immunosuppressive agents, for acquired TTP. These treatment methods are not always effective; therefore, new treatment methods are highly necessary. N-acetylcysteine (NAC), an FDA-approved anti-mucolytic agent, is a possible new treatment strategy for TTP, as it was demonstrated to reduce disulfide bonds in VWF, thereby decreasing VWF multimers size and hence their prothrombotic potential. We investigated whether NAC, without concurrent plasma exchange and immunosuppressive therapy, is effective in preventing and resolving TTP signs, using well-established murine and baboon models for TTP. In mice, prophylactic administration of NAC was effective in preventing severe TTP signs. This in vivo finding was supported by in vitro data demonstrating the VWF multimer-reducing properties of NAC in solution. Nonetheless, in both mice and baboons, administration of NAC was not effective in resolving preexisting TTP signs; thrombocytopenia, hemolytic anemia, and organ damage could not be reversed, as thrombus resolution was not achieved. Failure to improve clinical outcome occurred even though a reduction in VWF multimers was observed, demonstrating that NAC was efficient in reducing disulfide bonds in circulating VWF multimers. In conclusion, prophylactic administration of NAC, without concurrent plasma exchange, was effective in preventing severe TTP signs in mice, but NAC was not effective in resolving preexistent acute TTP signs in mice and baboons.


Assuntos
Acetilcisteína/uso terapêutico , Multimerização Proteica/efeitos dos fármacos , Púrpura Trombocitopênica Trombótica/prevenção & controle , Fator de von Willebrand/metabolismo , Proteína ADAMTS13/genética , Proteína ADAMTS13/metabolismo , Animais , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Feminino , Deleção de Genes , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Papio , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Púrpura Trombocitopênica Trombótica/genética , Púrpura Trombocitopênica Trombótica/metabolismo , Fator de von Willebrand/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...