Enhanced platelet MRP4 expression and correlation with platelet function in patients under chronic aspirin treatment.
Platelet multidrug resistance protein4 (MRP4)-overexpression has a role in reducing aspirin action. Aspirin in vivo treatment enhances platelet MRP4 expression and MRP4 mediated transport inhibition reduces platelet function and delays thrombus formation. The aim of our work was to verify whether MRP4 expression is enhanced in platelets obtained from patients under chronic aspirin treatment and whether it correlates with residual platelet reactivity. We evaluated changes on mRNA and protein-MRP4 expression and platelet aggregation in four populations: healthy volunteers (HV), aspirin-free control population (CTR), patients who started the treatment less than one month ago (ASA<1 month patients) and aspirinated patients who started the treatment more than two months ago (ASA>2 months patients). In platelets obtained from ASA>2 months patients, it was found a statistically significant MRP4 enhancement of both mRNA and protein expression compared to HV, CTR and ASA<1 month patients. Platelets obtained from ASA>2 months patients that present high levels of platelet MRP4, have higher serum TxB2levels and collagen-induced platelet aggregation compared to patient with low levels of MRP4 in platelets. In addition collagen induced platelet aggregation is higher in in vitro aspirinated platelets obtained from patients with high levels of MRP4 patients compared to those obtained from patients with low MRP4 levels. We can assert that, in patients under chronic aspirin treatment, platelets that present high MRP4 levels have an increase of residual platelet reactivity, which is due in part to incomplete COX-1 inhibition, and in part to COX-1-independent mechanism.
Isabella
I
Massimi
Lavinia Vittoria
LV
Lotti
Flavia
F
Temperilli
Massimo
M
Mancone
Gennaro
G
Sardella
Simone
S
Calcagno
Ombretta
O
Turriziani
Luigi
L
Frati
Fabio M. Pulcinelli, MD, Department of Experimental Medicine, "Sapienza" University of Rome, Viale Regina Elena 324, 00161, Rome, Italy, Tel.: +39 06 49973002, Fax: +39 06 4452955, E-mail: fabio.pulcinelli@uniroma1.it.
Fabio M
FM
Pulcinelli
D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D010974:Platelet Aggregation; D010975:Platelet Aggregation Inhibitors; D010979:Platelet Function Tests
D001241:Aspirin; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010975:Platelet Aggregation Inhibitors; C073492:ABCC4 protein, human
MRP4; Platelet; aspirin; gene expression; platelet aggregation