Platelet protease-activated receptor 1 and membrane expression of P-selectin in pulmonary arterial hypertension.
Thromb Res
; 125(1): 38-43, 2010 Jan.
Article
em En
| MEDLINE
| ID: mdl-19447475
ABSTRACT
INTRODUCTION:
Pulmonary arterial hypertension (PAH) is frequently associated with thrombotic events, particularly involving the pulmonary microcirculation at sites of vascular injury. We therefore decided to analyse protease-activated receptor 1 (PAR1), a key element in the activation of human platelets by thrombin, in PAH patients in stable clinical condition.METHODS:
Using flow cytometry, we analyzed platelet PAR1 density, PAR1-mediated exposure of P-selectin and the formation of platelet-leukocyte aggregates in 30 PAH patients aged 11 to 78 years (median 50.5 years). The control group consisted of 25 healthy subjects with the same age range as patients.RESULTS:
In patients, total platelet PAR1 density and uncleaved PAR1 density correlated negatively with platelet count (r(2)=0.33 and r(2)=0.34 respectively, p<0.0015). In patients with a low platelet count (<150x10(9) platelets/L), both densities were increased relative to controls (82% and 33% respectively, p<0.05). Thrombin peptide-induced platelet exposure of P-selectin was directly related to total and uncleaved PAR1 density (respectively, r(2)=0.33 and r(2)=0.29, p<0.0025) and increased in subjects with low platelet count (46% versus those with normal platelet count, p<0.05). Patients with low platelet count had decreased in vitro thrombin-induced formation of platelet-leukocyte aggregates (57% decrease versus controls, p<0.05).CONCLUSIONS:
There seems to be a subpopulation of PAH patients with increased propensity to thrombotic events as suggested by increased platelet PAR1 expression and PAR-mediated surface exposure of P-selectin associated with decreased platelet count.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Artéria Pulmonar
/
Plaquetas
/
Selectina-P
/
Receptor PAR-1
/
Hipertensão Pulmonar
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Adolescent
/
Adult
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Female
/
Humans
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Male
Idioma:
En
Revista:
Thromb Res
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Brasil