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(Arteriosclerosis, Thrombosis, and Vascular Biology. 2008;28:947.)
© 2008 American Heart Association, Inc.

Clinical and Population Studies

Tissue Factor in Patients With Acute Coronary Syndromes

Expression in Platelets, Leukocytes, and Platelet-Leukocyte Aggregates

Marta Brambilla; Marina Camera; Deborah Colnago; Giancarlo Marenzi; Monica De Metrio; Peter L. Giesen; Alessandra Balduini; Fabrizio Veglia; Karl Gertow; Paolo Biglioli; Elena Tremoli

From the Department of Pharmacological Sciences (M.B., M.C., E.T.), University of Milan, Italy; Centro Cardiologico Monzino IRCCS (M.C., D.C., G.M., M.D.M., F.V., K.G., P.B., E.T.), Milan, Italy; the Department of Biochemistry (A.B.), University of Pavia, Italy; and Thrombinoscope CV (P.L.G.), Maastricht, The Netherlands.

Correspondence to Dr Marina Camera, Department of Pharmacological Sciences, University of Milan, Via Balzaretti, 9, 20133 Milan, Italy. E-mail Marina.Camera{at}ccfm.it

Abstract

Objective— Activated platelets and circulating platelet-leukocyte aggregates (PLA) are significantly higher in patients with unstable angina than in those with stable angina (SA). Platelets from healthy subjects express TF on activation. The aim of this study was to investigate the expression of TF in PLA, in platelets, and in monocytes of acute coronary syndrome (ACS) patients compared to SA patients and healthy subjects (Controls).

Methods and Results— We enrolled 26 consecutive patients with ACS, 29 patients with SA, and 25 Controls. A significantly greater number of total and TF positive platelet-monocyte aggregates was found by flow cytometry in blood of ACS patients than in either SA patients (3-fold) or Controls (5-fold). ACS patients also had a significantly higher amount of TF-positive platelets than SA or Controls (>3-fold) and significantly higher thrombin generation capacity. TF mRNA expression in platelets was significantly higher in ACS patients than in SA or Controls.

Conclusions— In ACS patients the greater expression of TF in platelets and PLA strengthens the link between platelet activation, blood coagulation, and thrombus formation and may further contribute to the hypercoagulability associated with the disease.

In ACS patients the number of TF-positive platelets and platelet-monocyte aggregates as well as the platelet-associated TF mRNA levels are significantly greater than in SA or Controls, strengthening the link between platelet activation, blood coagulation, and thrombus formation, and may further contribute to the hypercoagulability associated with the disease.

Key Words: platelets • platelet-leukocyte aggregates • tissue factor • acute coronary syndrome • thrombosis