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2.
Int J Mol Sci ; 21(14)2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32708334

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2), also known as coronavirus disease 2019 (COVID-19)-induced infection, is strongly associated with various coagulopathies that may result in either bleeding and thrombocytopenia or hypercoagulation and thrombosis. Thrombotic and bleeding or thrombotic pathologies are significant accompaniments to acute respiratory syndrome and lung complications in COVID-19. Thrombotic events and bleeding often occur in subjects with weak constitutions, multiple risk factors and comorbidities. Of particular interest are the various circulating inflammatory coagulation biomarkers involved directly in clotting, with specific focus on fibrin(ogen), D-dimer, P-selectin and von Willebrand Factor (VWF). Central to the activity of these biomarkers are their receptors and signalling pathways on endothelial cells, platelets and erythrocytes. In this review, we discuss vascular implications of COVID-19 and relate this to circulating biomarker, endothelial, erythrocyte and platelet dysfunction. During the progression of the disease, these markers may either be within healthy levels, upregulated or eventually depleted. Most significant is that patients need to be treated early in the disease progression, when high levels of VWF, P-selectin and fibrinogen are present, with normal or slightly increased levels of D-dimer (however, D-dimer levels will rapidly increase as the disease progresses). Progression to VWF and fibrinogen depletion with high D-dimer levels and even higher P-selectin levels, followed by the cytokine storm, will be indicative of a poor prognosis. We conclude by looking at point-of-care devices and methodologies in COVID-19 management and suggest that a personalized medicine approach should be considered in the treatment of patients.


Assuntos
Plaquetas/metabolismo , Infecções por Coronavirus/patologia , Células Endoteliais/metabolismo , Eritrócitos/metabolismo , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Selectina-P/metabolismo , Pneumonia Viral/patologia , Fator de von Willebrand/metabolismo , Betacoronavirus , Síndrome da Liberação de Citocina/patologia , Humanos , Pandemias , Sistemas Automatizados de Assistência Junto ao Leito , Medicina de Precisão/métodos , Trombocitopenia/patologia , Trombose/patologia
3.
Curr Probl Cardiol ; 45(9): 100648, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32703535

RESUMO

The exceptional outbreak of COVID-19 pandemic has let the scientific community to work closely and quickly learnt things in a very short period of time. This has let us recognize that thromboembolic complications are responsible for morbidity and mortality among the COVID-19 infected patients. Available data have suggested a possible multifactorial basis of these complications, and while efforts are being made to treat this infection, preventive measures with the use of systemic anticoagulation were quickly adopted to deal with this issue. Despite obvious benefits as appeared with the use of systemic anticoagulation, most of the emerged data were retrospective, hence raise questions on the possible interplay of the confounders as well as long-term benefits and safety of systemic anticoagulation.


Assuntos
Anticoagulantes/uso terapêutico , Transtornos da Coagulação Sanguínea/sangue , Infecções por Coronavirus/sangue , Pneumonia Viral/sangue , Tromboembolia/sangue , Betacoronavirus , Transtornos da Coagulação Sanguínea/tratamento farmacológico , Transtornos da Coagulação Sanguínea/etiologia , Infecções por Coronavirus/complicações , Infecções por Coronavirus/tratamento farmacológico , Coagulação Intravascular Disseminada/sangue , Coagulação Intravascular Disseminada/tratamento farmacológico , Coagulação Intravascular Disseminada/etiologia , Células Endoteliais , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Heparina/uso terapêutico , Heparina de Baixo Peso Molecular/uso terapêutico , Humanos , Pandemias , Pneumonia Viral/complicações , Pneumonia Viral/tratamento farmacológico , Tromboembolia/tratamento farmacológico , Tromboembolia/etiologia , Receptores Toll-Like/metabolismo , Fator de von Willebrand/metabolismo
4.
Arterioscler Thromb Vasc Biol ; 40(9): 2187-2194, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32640909

RESUMO

OBJECTIVE: Aortic stenosis may be complicated by an acquired von Willebrand syndrome that rarely causes significant bleeding, raising the question of why it does so in a few cases. To seek an explanation, we studied 5 severe bleeder aortic stenosis patients in a cohort of 49 patients, using the flowchart for inherited von Willebrand disease. Approach and Results: All 5 patients were lacking in large and intermediate VWF (von Willebrand factor) multimers, 3 had reduced plasma and platelet VWF levels, and none showed PFA100 closure. Two patients (those with most multimers missing) also had a short VWF half-life. Genetic analyses on the 3 patients with reduced platelet VWF levels revealed that one carried both the c.1164C>G and the c.7880G>A mutations, and another carried the c.3390C>T mutation, while the third had one of the 2 VWF alleles relatively less expressed than the other (25% versus 75%). No genetic alterations emerged in the other 2 patients. Successful replacement of the stenotic aortic valve, performed in the 2 patients with VWF mutations, did not correct their abnormal VWF multimer picture-unlike what happened in the aortic stenosis patients without bleeding symptoms. CONCLUSIONS: Our findings suggest that acquired von Willebrand syndrome can develop in patients with hitherto-undiagnosed inherited von Willebrand disease. Since von Willebrand disease is the most common bleeding disorder, this possibility should be considered in aortic stenosis patients-especially those with a more severe bleeding history and more disrupted VWF laboratory patterns-because they risk hemorrhage during aortic valve replacement.


Assuntos
Estenose da Valva Aórtica/cirurgia , Implante de Prótese Vascular/efeitos adversos , Hemostasia , Hemorragia Pós-Operatória/etiologia , Doenças de von Willebrand/complicações , Fator de von Willebrand/metabolismo , Idoso , Idoso de 80 Anos ou mais , Estenose da Valva Aórtica/complicações , Estenose da Valva Aórtica/diagnóstico por imagem , Biomarcadores/sangue , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Meia-Vida , Hemostasia/genética , Humanos , Masculino , Mutação , Fenótipo , Hemorragia Pós-Operatória/sangue , Hemorragia Pós-Operatória/diagnóstico , Valor Preditivo dos Testes , Multimerização Proteica , Estabilidade Proteica , Proteólise , Medição de Risco , Fatores de Risco , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do Tratamento , Doenças de von Willebrand/sangue , Doenças de von Willebrand/diagnóstico , Doenças de von Willebrand/genética , Fator de von Willebrand/genética
5.
Clin Med (Lond) ; 20(5): e178-e182, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32694169

RESUMO

BACKGROUND: COVID-19 infection is characterised, among other features, by a prothrombotic state with high rate of venous thromboembolism (VTE), D-dimer, and fibrinogen levels. Clinical observations have also highlighted that these patients have elevated von Willebrand factor (vWF) and factor VIIIc. METHODS: 24 consecutive COVID-19 positive patients were selected from the intensive care unit (ICU) or the high acuity ward of Brighton and Sussex University Hospitals NHS Trust. RESULTS: The rate of VTE was 25% and mortality rate was 16.7%. Fibrinogen and D-Dimers were elevated, 7.9 (1.6) g/L and 2.4 (2.02) ug/ml respectively. Factor VIIIc and von vWF antigen levels were both extremely elevated at 279 (148) u/dL and 350 (131) % respectively, which are comparable to levels seen in ICU patients with severe sepsis. vWF levels were significantly higher in patients that died (p=0.017) and showed a positive correlation with age. There was a statistically significant association between COVID-19 disease and non-O blood group (p=0.02); 80% (4/5) of COVID-19 patients with VTE were blood group A. CONCLUSION: Very high levels of vWF and factor VIIIc are common in COVID-19 patients, comparable to levels in severely septic non-COVID ICU patients. This could contribute to the hypercoagulable state and increased VTE rate in COVID-19. Further studies are needed to evaluate the use of vWF for stratifying thrombotic risk in COVID-19 and to determine if elevated vWF is contributing to disease pathogenesis.


Assuntos
Infecções por Coronavirus/complicações , Endotélio Vascular/patologia , Mortalidade Hospitalar/tendências , Pneumonia Viral/complicações , Síndrome Respiratória Aguda Grave/sangue , Tromboembolia Venosa/etiologia , Fator de von Willebrand/metabolismo , Biomarcadores/sangue , Estudos de Coortes , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/mortalidade , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Fibrinogênio/metabolismo , Hospitais Universitários , Humanos , Unidades de Terapia Intensiva , Masculino , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/mortalidade , Medição de Risco , Amostragem , Síndrome Respiratória Aguda Grave/diagnóstico , Taxa de Sobrevida , Reino Unido , Tromboembolia Venosa/sangue , Tromboembolia Venosa/mortalidade
6.
Nucleic Acids Res ; 48(13): 7333-7344, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32496552

RESUMO

Neutrophils release their intracellular content, DNA included, into the bloodstream to form neutrophil extracellular traps (NETs) that confine and kill circulating pathogens. The mechanosensitive adhesive blood protein, von Willebrand Factor (vWF), interacts with the extracellular DNA of NETs to potentially immobilize them during inflammatory and coagulatory conditions. Here, we elucidate the previously unknown molecular mechanism governing the DNA-vWF interaction by integrating atomistic, coarse-grained, and Brownian dynamics simulations, with thermophoresis, gel electrophoresis, fluorescence correlation spectroscopy (FCS), and microfluidic experiments. We demonstrate that, independently of its nucleotide sequence, double-stranded DNA binds to a specific helix of the vWF A1 domain, via three arginines. This interaction is attenuated by increasing the ionic strength. Our FCS and microfluidic measurements also highlight the key role shear-stress has in enabling this interaction. Our simulations attribute the previously-observed platelet-recruitment reduction and heparin-size modulation, upon establishment of DNA-vWF interactions, to indirect steric hindrance and partial overlap of the binding sites, respectively. Overall, we suggest electrostatics-guiding DNA to a specific protein binding site-as the main driving force defining DNA-vWF recognition. The molecular picture of a key shear-mediated DNA-protein interaction is provided here and it constitutes the basis for understanding NETs-mediated immune and hemostatic responses.


Assuntos
DNA/química , Simulação de Acoplamento Molecular , Fator de von Willebrand/química , Sítios de Ligação , DNA/metabolismo , Humanos , Simulação de Dinâmica Molecular , Concentração Osmolar , Ligação Proteica , Eletricidade Estática , Fator de von Willebrand/metabolismo
7.
PLoS One ; 15(6): e0234501, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32525962

RESUMO

Shear-induced conformational changes of von Willebrand factor (VWF) play an important role in platelet activation. A novel approach describing VWF unfolding on the platelet surface under dynamic shear stress is proposed. Cumulative effect of dynamic shear on platelet activation via conformational changes of VWF is analysed. The critical condition of shear-induced platelet activation is formulated. The explicit expression for the threshold value of cumulative shear stress as a function of VWF multimer size is derived. The results open novel prospects for pharmacological regulation of shear-induced platelet activation through control of VWF multimers size distribution.


Assuntos
Plaquetas/fisiologia , Modelos Biológicos , Ativação Plaquetária/fisiologia , Estrutura Quaternária de Proteína/fisiologia , Fator de von Willebrand/metabolismo , Humanos , Simulação de Dinâmica Molecular , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Multimerização Proteica/fisiologia , Estabilidade Proteica , Estresse Mecânico , Relação Estrutura-Atividade
9.
Arterioscler Thromb Vasc Biol ; 40(6): 1441-1453, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32375545

RESUMO

Megakaryocyte-derived platelets and endothelial cells store their hemostatic cargo in α- and δ-granules and Weibel-Palade bodies, respectively. These storage granules belong to the lysosome-related organelles (LROs), a heterogeneous group of organelles that are rapidly released following agonist-induced triggering of intracellular signaling pathways. Following vascular injury, endothelial Weibel-Palade bodies release their content into the vascular lumen and promote the formation of long VWF (von Willebrand factor) strings that form an adhesive platform for platelets. Binding to VWF strings as well as exposed subendothelial collagen activates platelets resulting in the release of α- and δ-granules, which are crucial events in formation of a primary hemostatic plug. Biogenesis and secretion of these LROs are pivotal for the maintenance of proper hemostasis. Several bleeding disorders have been linked to abnormal generation of LROs in megakaryocytes and endothelial cells. Recent reviews have emphasized common pathways in the biogenesis and biological properties of LROs, focusing mainly on melanosomes. Despite many similarities, LROs in platelet and endothelial cells clearly possess distinct properties that allow them to provide a highly coordinated and synergistic contribution to primary hemostasis by sequentially releasing hemostatic cargo. In this brief review, we discuss in depth the known regulators of α- and δ-granules in megakaryocytes/platelets and Weibel-Palade bodies in endothelial cells, starting from transcription factors that have been associated with granule formation to protein complexes that promote granule maturation. In addition, we provide a detailed view on the interplay between platelet and endothelial LROs in controlling hemostasis as well as their dysfunction in LRO related bleeding disorders.


Assuntos
Plaquetas/ultraestrutura , Grânulos Citoplasmáticos/fisiologia , Células Endoteliais/ultraestrutura , Hemostasia/fisiologia , Lisossomos/fisiologia , Transtornos da Coagulação Sanguínea/genética , Transtornos da Coagulação Sanguínea/fisiopatologia , Colágeno/fisiologia , Grânulos Citoplasmáticos/ultraestrutura , Humanos , Lisossomos/ultraestrutura , Corpos de Weibel-Palade/fisiologia , Corpos de Weibel-Palade/ultraestrutura , Fator de von Willebrand/metabolismo
10.
Thromb Haemost ; 120(5): 793-804, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32369850

RESUMO

BACKGROUND: Accurate diagnosis of symptomatic low von Willebrand factor (VWF) remains a major challenge in von Willebrand disease (VWD). However, present tests do not adequately take into account flow forces that, at very high shear rates, reveal a weakness in the VWF-platelet glycoprotein glycoprotein Ib bond in normal subjects. The degree of this weakness is greater in symptomatic, but not asymptomatic, low VWF. OBJECTIVE: The aim of this study is to distinguish patients with symptomatic low VWF (levels in the 30-50 IU/dL range) from those with asymptomatic low VWF and normal subjects. METHODS: We measured platelet adhesion (PA)/aggregation in our novel microfluidic flow system that permits real-time assessment of PA (surface coverage) and PA/aggregation (V, aggregate volume) using epifluorescence digital videomicroscopy in flowing noncitrated whole blood at 4,000 second-1. Blood samples from 24 low VWF patients and 15 normal subjects were collected into plastic tubes containing 4 U/mL enoxaparin. MetaMorph software was used to quantify rates of PA and V increase. RESULTS: Rates of PA increase showed a bimodal distribution, with values for 16/24 patients (Group I) all below the 2.5th percentile of normal, and values for 8/24 patients (Group II) similar to controls. Bleeding scores (mean ± standard error) were 5.50 ± 0.45 versus 2.75 ± 0.45 (p = 0.00077), and 10 clinically significant bleeding events were observed in seven versus zero (p = 0.0295) Group I and Group II subjects, respectively. CONCLUSION: The present approach may offer a definitive means to distinguish symptomatic low VWF from either asymptomatic low VWF or normal controls.


Assuntos
Adesividade Plaquetária , Agregação Plaquetária , Testes de Função Plaquetária , Doenças de von Willebrand/diagnóstico , Fator de von Willebrand/metabolismo , Adolescente , Adulto , Doenças Assintomáticas , Biomarcadores/sangue , Velocidade do Fluxo Sanguíneo , Estudos de Casos e Controles , Criança , Pré-Escolar , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Técnicas Analíticas Microfluídicas , Microscopia de Vídeo , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estresse Mecânico , Fatores de Tempo , Adulto Jovem , Doenças de von Willebrand/sangue , Doenças de von Willebrand/complicações
11.
Subcell Biochem ; 94: 437-464, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32189311

RESUMO

Von Willebrand factor (VWF) and coagulation factor VIII (FVIII) circulate as a complex in plasma and have a major role in the hemostatic system. VWF has a dual role in hemostasis. It promotes platelet adhesion by anchoring the platelets to the subendothelial matrix of damaged vessels and it protects FVIII from proteolytic degradation. Moreover, VWF is an acute phase protein that has multiple roles in vascular inflammation and is massively secreted from Weibel-Palade bodies upon endothelial cell activation. Activated FVIII on the other hand, together with coagulation factor IX forms the tenase complex, an essential feature of the propagation phase of coagulation on the surface of activated platelets. VWF deficiency, either quantitative or qualitative, results in von Willebrand disease (VWD), the most common bleeding disorder. The deficiency of FVIII is responsible for Hemophilia A, an X-linked bleeding disorder. Here, we provide an overview on the role of the VWF-FVIII interaction in vascular physiology.


Assuntos
Fenômenos Fisiológicos Cardiovasculares , Fator VIII/metabolismo , Fator de von Willebrand/metabolismo , Fator VIII/química , Hemofilia A/metabolismo , Humanos , Doenças de von Willebrand/metabolismo , Fator de von Willebrand/química
12.
Toxicon ; 178: 92-99, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32135198

RESUMO

Opossums in the clade Didelphini are well known to be resistant to snake venom due to endogenous circulating inhibitors which target metalloproteinases and phospholipases. However, the mechanisms through which these opossums cope with a variety of other damaging venom proteins are unknown. A protein involved in blood clotting (von Willebrand Factor) has been found to have undergone rapid adaptive evolution in venom-resistant opossums. This protein is a known target for a subset of snake venom C-type lectins (CTLs), which bind it and then induce it to bind platelets, causing hemostatic disruption. Several amino acid changes in vWF unique to these opossums could explain their resistance; however, experimental evidence that these changes disrupt venom CTL binding was lacking. We used platelet aggregation assays to quantify resistance to a venom-induced platelet response in two species of venom-resistant opossums (Didelphis virginiana, Didelphis aurita), and one venom-sensitive opossum (Monodelphis domestica). We found that all three species have lost nearly all their aggregation response to the venom CTLs tested. Using washed platelet assays we showed that this loss of aggregation response is not due to inhibitors in the plasma, but rather to the failure of either vWF or platelets (or both) to respond to venom CTLs. These results demonstrate the potential adaptive function of a trait previously shown to be evolving under positive selection. Surprisingly, these findings also expand the list of potentially venom tolerant species to include Monodelphis domestica and suggest that an ecological relationship between opossums and vipers may be a broader driver of adaptive evolution across South American marsupials than previously thought.


Assuntos
Adaptação Fisiológica/fisiologia , Didelphis/fisiologia , Venenos de Serpentes/toxicidade , Fator de von Willebrand/metabolismo , Animais , Plaquetas/metabolismo , Lectinas Tipo C/metabolismo , Metaloproteases/metabolismo , Agregação Plaquetária , Venenos de Serpentes/química , Venenos de Serpentes/metabolismo , América do Sul
13.
Biochim Biophys Acta Mol Cell Res ; 1867(6): 118681, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32084444

RESUMO

Lipid droplets (LDs) play regulatory role in various cells but their significance in endothelial pathophysiology is still not well understood. Here, we studied LDs in in situ endothelial cells (ECs) in isolated blood vessels stimulated with pro-inflammatory or pro-apoptotic stimuli using Raman and fluorescence imaging. Endothelial inflammation induced by murine TNF-α (mTNF-α) was featured by overexpression of ICAM-1, vWF, increased production of PGI2, and was associated with the formation of low number of LDs. However in the presence of atglistatin, the inhibitor of triacyclglycerols hydrolysis, the number of LDs significantly increased. In contrast, in endothelium stimulated by human TNF-α (hTNF-α) or FasL, apart from endothelial inflammation, displayed also apoptosis as evidenced by high annexin expression and significant LDs formation. Raman imaging confirmed that LDs were localized in endothelium and revealed significant heterogeneity in biochemical composition of endothelial LDs that dependent on endothelial stimuli. Repertoire of LDs included LDs rich in highly unsaturated lipids, assigned to the inflammation, as well as LDs featured by more saturated lipids linked to apoptosis, where Raman signals indicating content of cholesterol and phospholipids were higher for endothelial apoptosis in comparison to endothelial inflammation. The heterogeneity in chemical composition of LDs suggested more complex pathophysiological role of endothelial LDs then previously appreciated.


Assuntos
Proteína Ligante Fas/farmacologia , Inflamação/metabolismo , Gotículas Lipídicas/química , Fator de Necrose Tumoral alfa/farmacologia , Animais , Células Cultivadas , Células Endoteliais/química , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Humanos , Molécula 1 de Adesão Intercelular , Camundongos , Compostos de Fenilureia/farmacologia , Prostaglandinas I/metabolismo , Análise Espectral Raman , Fator de von Willebrand/metabolismo
14.
BMC Cardiovasc Disord ; 20(1): 72, 2020 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-32039706

RESUMO

BACKGROUND: Prediction of major adverse cardiovascular events (MACEs) may offer great benefits for patients with coronary artery disease (CAD). Von Willebrand factor (vWF) is stored in endothelial cells and released into blood plasma upon vascular dysfunction. This meta-analysis was performed to evaluate the prognostic value of plasma vWF levels in CAD patients with MACEs. METHODS: A total of 15 studies were included in this meta-analysis through the search in PubMed, Embase and CNKI. Data were collected from 960 patients who had MACEs after CAD and 3224 controls nested without the adverse events. The standard mean difference (SMD) and 95% confidence intervals (95% CI) were calculated using random-effects model. RESULTS: The plasma vWF levels examined at 24 h and 48 h after admission were significantly higher in CAD patients with MACEs than those without. The pooled SMD among the MACEs group and the non-MACEs group was 0.55 (95% CI = 0.30-0.80, P < 0.0001) and 0.70 (95% CI = 0.27-1.13, P = 0.001), respectively. However, no significant difference was found in plasma vWF levels on admission between the two groups. CONCLUSION: Plasma vWF level in CAD patients examined at 24 h and 48 h after admission might be an independent prognostic factor for MACE.


Assuntos
Doenças Cardiovasculares/sangue , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Fator de von Willebrand/metabolismo , Idoso , Biomarcadores/sangue , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/fisiopatologia , Doenças Cardiovasculares/terapia , Endotélio Vascular/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Admissão do Paciente , Valor Preditivo dos Testes , Prognóstico , Fatores de Tempo , Regulação para Cima
15.
Clin Appl Thromb Hemost ; 26: 1076029619892684, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32088973

RESUMO

CONCLUSION: von Willebrand factor is a useful predictor and prognostic measure for TA-TMA, which may help clinicians identify and manage this life-threatening disease earlier.


Assuntos
Microangiopatias Trombóticas/etiologia , Fator de von Willebrand/metabolismo , Adulto , Feminino , Humanos , Masculino , Microangiopatias Trombóticas/sangue , Adulto Jovem
16.
Int J Nanomedicine ; 15: 901-912, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32103945

RESUMO

Background: Aortic valve disease is the most common valvular heart disease leading to valve replacement. The efficacy of pharmacological therapy for aortic valve disease is limited by the high mechanical stress at the aortic valves impairing the binding rate. We aimed to identify nanoparticle coating with entire platelet membranes to fully mimic their inherent multiple adhesive mechanisms and target the sclerotic aortic valve of apolipoprotein E-deficient (ApoE-/-) mice based on their multiple sites binding capacity under high shear stress. Methods: Considering the potent interaction of platelet membrane glycoproteins with components present in sclerotic aortic valves, platelet membrane-coated nanoparticles (PNPs) were synthetized and the binding capacity under high shear stress was evaluated in vitro and in vivo. Results: PNPs demonstrated effectively adhering to von Willebrand factor, collagen and fibrin under shear stresses in vitro. In an aortic valve disease model established in ApoE-/- mice, PNPs exhibited good targeting to sclerotic aortic valves by mimicking platelet multiple adhesive mechanisms. Conclusion: PNPs could provide a promising platform for the molecular diagnosis and targeting treatment of aortic valve disease.


Assuntos
Plaquetas/citologia , Doenças das Valvas Cardíacas/tratamento farmacológico , Nanopartículas/química , Nanopartículas/metabolismo , Animais , Valva Aórtica/efeitos dos fármacos , Valva Aórtica/patologia , Apolipoproteínas E/genética , Plaquetas/química , Membrana Celular/química , Colágeno/metabolismo , Modelos Animais de Doenças , Fibrina/metabolismo , Cardiopatias Congênitas , Doenças das Valvas Cardíacas/patologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , Nanopartículas/uso terapêutico , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Esclerose , Estresse Mecânico , Fator de von Willebrand/metabolismo
17.
mSphere ; 5(1)2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941807

RESUMO

Protective antigen (PA) is a component of anthrax toxin that can elicit toxin-neutralizing antibody responses. PA is also the major antigen in the current vaccine to prevent anthrax, but stability problems with recombinant proteins have complicated the development of new vaccines containing recombinant PA. The relationship between antigen physical stability and immunogenicity is poorly understood, but there are theoretical reasons to think that this parameter can affect immune responses. We investigated the immunogenicity of anthrax PA, in the presence and absence of the soluble von Willebrand factor A domain of the human form of receptor capillary morphogenesis protein 2 (sCMG2), to elicit antibodies to PA in BALB/c mice. Prior studies showed that sCMG2 stabilizes the 83-kDa PA structure to pH, chemical denaturants, temperature, and proteolysis and slows the hydrogen-deuterium exchange rate of histidine residues far from the binding interface. In contrast to a vaccine containing PA without adjuvant, we found that mice immunized with PA in stable complex with sCMG2 showed markedly reduced antibody responses to PA, including toxin-neutralizing antibodies and antibodies to domain 4, which correlated with fewer toxin-neutralizing antibodies. In contrast, mice immunized with PA in concert with a nonbinding mutant of sCMG2 (D50A) showed anti-PA antibody responses similar to those observed with PA alone. Our results suggest that addition of sCMG2 to a PA vaccine formulation is likely to result in a significantly diminished immune response, but we discuss the multitude of factors that could contribute to reduced immunogenicity.IMPORTANCE The anthrax toxin PA is the major immunogen in the current anthrax vaccine (anthrax vaccine adsorbed). Improving the anthrax vaccine for avoidance of a cold chain necessitates improvements in the thermodynamic stability of PA. We address how stabilizing PA using sCMG2 affects PA immunogenicity in BALB/c mice. Although the stability of PA is increased by binding to sCMG2, PA immunogenicity is decreased. This study emphasizes that, while binding of a ligand retains or improves conformational stability without affecting the native sequence, epitope recognition or processing may be affected, abrogating an effective immune response.


Assuntos
Vacinas contra Antraz/imunologia , Antígenos de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Imunogenicidade da Vacina , Receptores de Peptídeos/imunologia , Fator de von Willebrand/metabolismo , Animais , Antraz/imunologia , Antraz/prevenção & controle , Anticorpos Antibacterianos/sangue , Anticorpos Neutralizantes/sangue , Antígenos de Bactérias/imunologia , Toxinas Bacterianas/imunologia , Epitopos/imunologia , Epitopos/metabolismo , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Ligação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Fator de von Willebrand/imunologia
18.
AJNR Am J Neuroradiol ; 41(1): 140-146, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31896567

RESUMO

BACKGROUND AND PURPOSE: Vascular devices generating high shear stress can cause type 2A acquired von Willebrand disease, which is characterized by low von Willebrand factor activity accompanied by hemorrhagic complications. The braided mesh structure of flow-diverting stents with a relatively small strut size can create abnormally high shear stress while arterial blood flows through the stent struts into the aneurysm, and flow-diverting stent may be associated with reduced von Willebrand factor activity. MATERIALS AND METHODS: Aneurysmal morphologic parameters and patient data were examined retrospectively among patients who had an unruptured intracranial aneurysm treated with a flow-diverting stent. The RISTOtest (test for whole blood ristocetin-induced platelet aggregation) for von Willebrand factor activity, as well as tests for aspirin and clopidogrel/prasugrel effectiveness, were performed immediately before the endovascular procedure and 24 hours later by multiple electrode aggregometry. RESULTS: A total of 39 patients with 56 aneurysms were recruited, and statistical analyses were performed in 32 patents with 49 aneurysms. Compared with the baseline values, von Willebrand factor activity was reduced in 16 patients but increased in 23 patients. Aneurysmal variables (eg, neck area, volume, volume-to-neck area ratio, size ratio, and morphologic index) clearly distinguished patients with reduced von Willebrand factor activity from those with nonreduced von Willebrand factor activity. The receiver operating characteristic curve showed that the morphologic index and volume had the highest discriminative power, with an area under the curve of 0.99. CONCLUSIONS: In high-volume/large-neck aneurysms, flow-diverting stent implantation can cause reduced von Willebrand factor activity, which may be linked causally to acquired von Willebrand disease.


Assuntos
Procedimentos Endovasculares/instrumentação , Aneurisma Intracraniano/terapia , Stents/efeitos adversos , Doença de von Willebrand Tipo 2/etiologia , Fator de von Willebrand/metabolismo , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Agregação Plaquetária/fisiologia , Estudos Retrospectivos , Adulto Jovem
19.
Clin Appl Thromb Hemost ; 26: 1076029619900552, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31964151

RESUMO

von Willebrand factor (VWF) acts as a bridge between platelets and the subendothelial matrix following vessel damage and plays a vital role in coronary artery disease (CAD). The aim of this study was to investigate the association between VWF and the severity of coronary stenosis quantified by the Gensini score in acute myocardial infarction (AMI), the most dangerous complication of CAD. Plasma VWF antigen (VWF: Ag) and VWF-collagen binding (VWF: CB) in normal controls (n = 123) and in patients with AMI (n = 205) were tested, and then the patients were divided based on Gensini scores. The levels of VWF: Ag and VWF: CB in patients with AMI were significantly higher than those in the control group (P < .001). Plasma levels of VWF: Ag and VWF: CB were positively correlated with both Gensini score and the number of affected vessels. Both VWF: Ag and VWF: CB were independent factors for coronary stenosis, adjusting confounding factors. Thus, the levels of VWF: Ag and VWF: CB were positively correlated with the severity of coronary stenosis. Screening of VWF at time of AMI may have prognostic value in terms of the severity of coronary stenosis.


Assuntos
Estenose Coronária/diagnóstico , Índice de Gravidade de Doença , Fator de von Willebrand/metabolismo , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio , Prognóstico
20.
Vascular ; 28(3): 309-313, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31902309

RESUMO

OBJECTIVES: In cardiovascular disease, deep vein thrombosis is one of the vital symptoms causing pulmonary thromboembolism. However, the pathogenesis of deep vein thrombosis is still not clear. One of the critical factors leading to deep vein thrombosis is the platelet aggregation that is mediated by a set of key genes including platelet membrane protein coded by platelet glycoprotein Ib alpha chain (GPIBA). METHODS: Deep vein thrombosis model was established according to the previous protocol, and venous blood and thrombi were collected for further analysis. RESULTS: The dynamic changes of GPIBA and coagulation factor, von Willebrand factor, were observed in deep vein thrombosis models. Meanwhile, critical proteins participating in adhesion and binding of platelets such as epithelial membrane protein 2 (EMP2), vascular cell adhesion protein 1 (VCAM1), immunoreceptor tyrosine-based activation motif 1 (ITAM1), integrin subunit alpha M (ITGAM), or fibronectin were also differentially expressed in deep vein thrombosis models. CONCLUSIONS: Application of heparin could reverse these dynamic changes in deep vein thrombosis models. Thus, we explained the potential synergic role of GPIBA and von Willebrand factor in regulating the occurrence of deep vein thrombosis and provide therapeutic target against cardiovascular disease.


Assuntos
Coagulação Sanguínea , Plaquetas/metabolismo , Agregação Plaquetária , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Trombose Venosa/metabolismo , Fator de von Willebrand/metabolismo , Animais , Coagulação Sanguínea/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Antígeno CD11b/metabolismo , Modelos Animais de Doenças , Fibrinolíticos/farmacologia , Fibronectinas/metabolismo , Heparina/farmacologia , Motivo de Ativação do Imunorreceptor Baseado em Tirosina , Glicoproteínas de Membrana/metabolismo , Camundongos , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação de Plaquetas/farmacologia , Transdução de Sinais , Molécula 1 de Adesão de Célula Vascular/metabolismo , Trombose Venosa/sangue , Trombose Venosa/prevenção & controle
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