Objectives In this study we investigate: 1) the role of multidrug resistance protein-4 (MRP4), an organic anion unidirectional transporter, in modulating aspirin action on human platelet cyclooxygenase (COX)-1; and 2) whether the impairment of aspirin-COX-1 interaction, found in coronary artery bypass grafting (CABG) patients, could be dependent on MRP4-mediated transport. Background Platelets of CABG patients present a reduced sensitivity to aspirin despite in vivo and in vitro drug treatment. Aspirin is an organic anion and could be a substrate for MRP4. Methods Intracellular aspirin concentration and drug COX-1 activity, measured by thrombin-induced thromboxane B2 (TxB2) production, were evaluated in platelets obtained from healthy volunteers (HV) and hematopoietic-progenitor cell cultures reducing or not reducing MRP4-mediated transport. Platelet MRP4 expression was evaluated, in platelets from HV and CABG patients, by dot-blot or by immunogold-electromicrographs or immunofluorescence-microscopy analysis. Results Inhibition of MRP4-mediated transport by dipyridamole or Mk-571 increases aspirin entrapment and its in vitro effect on COX-1 activity (142.7 +/- 34.6 pg/10(8) cells vs. 343.7 +/- 169.3 pg/10(8) cells TxB2-production). Platelets derived from megakaryocytes transfected with MRP4 small interfering ribonucleic acid have a higher aspirin entrapment and drug COX-1 activity. Platelets from CABG patients showed a high expression of MRP4 whose in vitro inhibition enhanced aspirin effect on COX-1 (349 +/- 141 pg/10(8) cells vs. 1,670 +/- 646 pg/10(8) cells TxB2-production). Conclusions Aspirin is a substrate for MRP4 and can be extruded from platelet through its transportation. Aspirin effect on COX-1 is little-related to MRP4-mediated aspirin transport in HV, but in CABG patients with MRP4 over-expression, its pharmacological inhibition enhances aspirin action in an efficient way. (J Am Coll Cardiol 2011;58:752-61) (C) 2011 by the American College of Cardiology Foundation
Aspirin Extrusion From Human Platelets Through Multidrug Resistance Protein-4-Mediated Transport Evidence of a Reduced Drug Action in Patients After Coronary Artery Bypass Grafting / Mattiello, Teresa; Raffaella, Guerriero; Lotti, Lavinia Vittoria; Trifirò, Elisabetta; Felli, MARIA PIA; Barbarulo, Alessandro; Bruna, Pucci; Gazzaniga, Paola; Gaudio, Carlo; Frati, Luigi; Pulcinelli, FABIO MARIA. - In: JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY. - ISSN 0735-1097. - STAMPA. - 58:7(2011), pp. 752-761. [10.1016/j.jacc.2011.03.049]
Aspirin Extrusion From Human Platelets Through Multidrug Resistance Protein-4-Mediated Transport Evidence of a Reduced Drug Action in Patients After Coronary Artery Bypass Grafting
MATTIELLO, TERESA;LOTTI, Lavinia Vittoria;TRIFIRÒ, Elisabetta;FELLI, MARIA PIA;BARBARULO, ALESSANDRO;GAZZANIGA, PAOLA;GAUDIO, Carlo;FRATI, Luigi;PULCINELLI, FABIO MARIA
2011
Abstract
Objectives In this study we investigate: 1) the role of multidrug resistance protein-4 (MRP4), an organic anion unidirectional transporter, in modulating aspirin action on human platelet cyclooxygenase (COX)-1; and 2) whether the impairment of aspirin-COX-1 interaction, found in coronary artery bypass grafting (CABG) patients, could be dependent on MRP4-mediated transport. Background Platelets of CABG patients present a reduced sensitivity to aspirin despite in vivo and in vitro drug treatment. Aspirin is an organic anion and could be a substrate for MRP4. Methods Intracellular aspirin concentration and drug COX-1 activity, measured by thrombin-induced thromboxane B2 (TxB2) production, were evaluated in platelets obtained from healthy volunteers (HV) and hematopoietic-progenitor cell cultures reducing or not reducing MRP4-mediated transport. Platelet MRP4 expression was evaluated, in platelets from HV and CABG patients, by dot-blot or by immunogold-electromicrographs or immunofluorescence-microscopy analysis. Results Inhibition of MRP4-mediated transport by dipyridamole or Mk-571 increases aspirin entrapment and its in vitro effect on COX-1 activity (142.7 +/- 34.6 pg/10(8) cells vs. 343.7 +/- 169.3 pg/10(8) cells TxB2-production). Platelets derived from megakaryocytes transfected with MRP4 small interfering ribonucleic acid have a higher aspirin entrapment and drug COX-1 activity. Platelets from CABG patients showed a high expression of MRP4 whose in vitro inhibition enhanced aspirin effect on COX-1 (349 +/- 141 pg/10(8) cells vs. 1,670 +/- 646 pg/10(8) cells TxB2-production). Conclusions Aspirin is a substrate for MRP4 and can be extruded from platelet through its transportation. Aspirin effect on COX-1 is little-related to MRP4-mediated aspirin transport in HV, but in CABG patients with MRP4 over-expression, its pharmacological inhibition enhances aspirin action in an efficient way. (J Am Coll Cardiol 2011;58:752-61) (C) 2011 by the American College of Cardiology FoundationI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
