Abstract

MONTEIRO, Maria-do-Céu et al. Aplicación de la citometría de flujo funcional a la monitorización del tratamiento antiplaquetario: Movilización de Ca²⁺ y expresión de P-Selectina en plaquetas de sujetos tratados con Ticlopidina. Rev Diagn Biol [online]. 2003, vol.52, n.1, pp.23-31. ISSN 0034-7973.

Patients with pre-thrombotic tendency are submitted to anti-platelet therapy. The resulting inhibition of platelet functions may influence the disease progression in individual patients. Thus, analytical procedures to measure objectively the functional status of the platelet population are of clinical utility. We have applied a novel whole-blood flow cytometric method (Monteiro et al. Cytometry 35, 302-310, 1999) to monitor the alterations in early platelet reactivity induced by oral administration of ticlopidine in five healthy volunteers (250 mg twice a day during four days). Platelet activation induced by ADP and thrombin was assessed in whole blood by flow cytometric kinetic determination of intracellular Ca²⁺ mobilization and compared to the late activation marker P-selectin (CD62P). Changes in both free Ca²⁺ and CD62P expression induced by ADP and thrombin reflected the inhibitory effect of ticlopidine. The intensity of Ca²⁺ responses (% inhibition <30%) and CD62P expression (% inhibition >50%) upon platelet activation by ADP and low-concentration thrombin were significantly reduced after ticlopidine treatment. Conclusions: Since marked interindividual variability was detected after ticlopidine administration, our results show the utility of these sensitive whole blood assays to monitor the inhibition of platelet function and to optimize accordingly the therapeutic dosage in the individual thrombotic patient.

Keywords : platelet activation; flow cytometry; Ca²⁺ mobilization; P-selectin; anti-platelet therapy.