OBJECTIVES: This prospective randomized study investigated platelet-induced upregulation of Mac-1 on monocytes and its inhibition by glycoprotein (GP) IIb/IIIa blockage in patients with acute myocardial infarction (AMI). BACKGROUND: In experimental AMI, Mac-1 on leukocytes is the pivotal adhesion molecule for detrimental inflammatory responses. In vitro, platelet adhesion to monocytes upregulates Mac-1. METHODS:Patients undergoing stenting in AMI within 48 h after onset of symptoms were randomly assigned to receive either standard-dose heparin (n = 50) or abciximab plus low-dose heparin (n = 50). In serial blood samples, we assessed platelet-monocyte interaction and Mac-1 surface expression by triple color immunofluorescence flow cytometry. RESULTS: Compared with platelet-negative monocytes, Mac-1 surface expression on monocytes with attached platelets was upregulated (median fluorescence intensity [interquartile range]: 259 [179 to 367] vs. 135 [78 to 195] arbitrary units, p < 0.001). As an indicator of platelet-monocyte interaction, mean fluorescence of the platelet marker GP Ib alpha in the monocytes population decreased after abciximab, although it remained unaffected by heparin alone. Abciximab achieved this effect by a reduction in platelet mass attached to monocytes (GP Ib alpha fluorescence intensity of heterotypic aggregates at 24 h [arbitrary units]: 187 [143 to 236] after abciximab vs. 228 [156 to 332] after heparin, p = 0.02), whereas it did not affect the percentage of monocytes with adherent platelets. Reduction of platelet-monocyte interaction resulted in decreased Mac-1 surface expression (fluorescence intensity at 24 h [arbitrary units]: 116 [68 to 153] after abciximab vs. 162 [117 to 239] after heparin, p = 0.001). CONCLUSIONS: In patients with AMI, platelet-leukocyte interactions modulate Mac-1 expression on monocytes. Glycoprotein IIb/IIIa blockade is a therapeutic option to interfere with this mechanism.
RCT Entities:
OBJECTIVES: This prospective randomized study investigated platelet-induced upregulation of Mac-1 on monocytes and its inhibition by glycoprotein (GP) IIb/IIIa blockage in patients with acute myocardial infarction (AMI). BACKGROUND: In experimental AMI, Mac-1 on leukocytes is the pivotal adhesion molecule for detrimental inflammatory responses. In vitro, platelet adhesion to monocytes upregulates Mac-1. METHODS:Patients undergoing stenting in AMI within 48 h after onset of symptoms were randomly assigned to receive either standard-dose heparin (n = 50) or abciximab plus low-dose heparin (n = 50). In serial blood samples, we assessed platelet-monocyte interaction and Mac-1 surface expression by triple color immunofluorescence flow cytometry. RESULTS: Compared with platelet-negative monocytes, Mac-1 surface expression on monocytes with attached platelets was upregulated (median fluorescence intensity [interquartile range]: 259 [179 to 367] vs. 135 [78 to 195] arbitrary units, p < 0.001). As an indicator of platelet-monocyte interaction, mean fluorescence of the platelet marker GP Ib alpha in the monocytes population decreased after abciximab, although it remained unaffected by heparin alone. Abciximab achieved this effect by a reduction in platelet mass attached to monocytes (GP Ib alpha fluorescence intensity of heterotypic aggregates at 24 h [arbitrary units]: 187 [143 to 236] after abciximab vs. 228 [156 to 332] after heparin, p = 0.02), whereas it did not affect the percentage of monocytes with adherent platelets. Reduction of platelet-monocyte interaction resulted in decreased Mac-1 surface expression (fluorescence intensity at 24 h [arbitrary units]: 116 [68 to 153] after abciximab vs. 162 [117 to 239] after heparin, p = 0.001). CONCLUSIONS: In patients with AMI, platelet-leukocyte interactions modulate Mac-1 expression on monocytes. Glycoprotein IIb/IIIa blockade is a therapeutic option to interfere with this mechanism.
Authors: Giuseppe De Luca; Harry Suryapranata; Menko-Jan de Boer; Jan Paul Ottervanger; Jan C A Hoorntje; A T Marcel Gosselink; Jan-Henk E Dambrink; Arnoud W J van't Hof Journal: J Thromb Thrombolysis Date: 2007-12-21 Impact factor: 2.300
Authors: Paul A Gurbel; Brian Galbut; Kevin P Bliden; Raymond D Bahr; Matthew T Roe; Victor L Serebruany; W Brian Gibler; Robert H Christenson; E Magnus Ohman Journal: J Thromb Thrombolysis Date: 2002-12 Impact factor: 2.300