Qualitative and quantitative modifications of von Willebrand factor in patients with essential thrombocythemia and controlled platelet count.
J Thromb Haemost
; 13(7): 1226-37, 2015 Jul.
Article
en En
| MEDLINE
| ID: mdl-25876231
ABSTRACT
BACKGROUND:
Essential thrombocythemia (ET) is characterized by increased platelets and prevalent thrombosis. An acquired von Willebrand factor (VWF) disease has been hypothesized and inconsistently associated with extreme thrombocytosis or rare bleeding in ET. Whether VWF is modified in ET patients with controlled platelet count remains unclear.OBJECTIVES:
We studied different VWF- and platelet-associated parameters in ET patients treated according to current recommendations. PATIENTS/METHODS:
Sixty-nine ET patients (M = 29; median age, 62 [48-70] years; platelets, 432 [337-620] × 10(3) µL(-1) ), 69 matched controls and 10 subjects with reactive thrombocytosis (RT) were studied. VWFantigen (Ag), activity (act), electrophoretic patterns, VWFpropeptide, plasma glycocalycin (GC), glycoproteinV (GpV), ADAMTS-13, elastase, C-reactive protein and serum thromboxane (TX)B2 were measured.RESULTS:
In ET patients, VWFAg was increased by 31 ± 13% vs. controls (P < 0.01), without dependence of blood groups, while VWFact was reduced by 21 ± 12% vs. controls and by 50 ± 24% vs. RT (P < 0.01). The VWFact/VWFAg ratios in ET were reduced by 35 ± 17% vs. controls and RT patients (P < 0.001) and significantly associated with immature or total platelet counts, GC, GpV and TXB2 . In multivariable analysis, only GC inversely predicted ET patients' VWFact/VWFAg ratios (ß = -0.42, P = 0.01). By electrophoresis analyses, high-molecular-weight VWF multimers were variably reduced with atypical cleavage bands in ET only. VWFpropeptide, ADAMTS-13 and elastase levels were normal in ET patients. Platelet-associated ADAM-10 and ADAM-17 hydrolyzed VWFm in vitro, showing patterns similar to those in ET samples.CONCLUSIONS:
In ET patients with controlled platelet counts, the VWFact/VWFAg ratio is decreased and predicted by GC, a product of platelet activation. ADAM-10 and/or ADAM-17 might be involved. In vivo platelet activation, which characterizes ET, might contribute to disease-specific VWF alterations.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Plaquetas
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Factor de von Willebrand
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Activación Plaquetaria
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Trombocitemia Esencial
Tipo de estudio:
Diagnostic_studies
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Observational_studies
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Prevalence_studies
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Prognostic_studies
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Qualitative_research
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Risk_factors_studies
Límite:
Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
J Thromb Haemost
Asunto de la revista:
HEMATOLOGIA
Año:
2015
Tipo del documento:
Article
País de afiliación:
Italia