Platelet-associated tissue factor enhances platelet reactivity and thrombin generation in experimental studies in vitro.
Thromb Res
; 130(6): e294-300, 2012 Dec.
Article
em En
| MEDLINE
| ID: mdl-23123135
ABSTRACT
INTRODUCTION:
The thrombogenic potential of tissue factor (TF) associated to platelets is controversial. We have investigated the in vitro contribution of platelet-associated TF to thrombus formation. MATERIALS ANDMETHODS:
Platelets suspensions were exposed to human TF-rich microvesicles (TF-MV) from placental or recombinant origin. Platelet-associated TF was quantified through coagulometric assays. Adhesive and cohesive properties of platelets containing TF were assessed in perfusion models using two thrombogenic surfaces 1) type-I collagen, or 2) damaged vascular segments. Perfusion studies were performed with heparinized blood enriched with a 30% of washed platelets exposed to TF-MV vs. washed control platelets. Thrombin generation and thromboelastometric properties of clots were also assessed using a fluorometric assay and ROTEM analysis, respectively. Inhibitory strategies with an antibody to TF were performed in some cases.RESULTS:
The addition of 30% of platelets containing TF to blood perfusates resulted in a statistically significant increase in the platelet coverage (%CS) vs. non-exposed platelets on collagen surfaces (%CS 19.7 ± 0.6 and 23.9 ± 0.7 respectively, vs.14.5 ± 1.4; p<0.01) and on the vascular subendothelium (%CS 54.0 ± 1.5 and 47.2 ± 6.8 respectively vs. 38.0 ± 3.5, p<0.05), with a statistically significant increase in the size of large platelet aggregates (p<0.05) vs. control platelets. These effects on collagen surfaces were almost totally prevented by an antibody to TF. Platelet-associated TF significantly accelerated thrombin generation and clot formation (p<0.05), effects that were partially prevented by a neutralizing anti-TF.CONCLUSIONS:
Platelet-associated TF potentiated adhesive and aggregating properties in in vitro studies with flowing blood and accelerated thrombin generation and clot formation time under steady conditions.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Plaquetas
/
Tromboplastina
/
Trombina
Tipo de estudo:
Etiology_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Animals
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Female
/
Humans
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article