EFFECTS OF TRIFLUSAL AND ITS MAIN METABOLITE HTB ON PLATELET INTERACTION WITH SUBENDOTHELIUM IN HEALTHY-VOLUNTEERS

The ex vivo effect of triflusal and acetylsalicylic acid (ASA) on platelet interaction with the subendothelium using the Baumgartner perfusion system (wall shear rate 350 s(-1)) was assessed in blood from 10 healthy volunteers who given a 15-day course of triflusal 600 mg per day and ASA 400 mg per day in a crossover trial. The percentage of platelets on the subendothelium showed a decrease of 62 % in samples from subjects on ASA and a decrease of 93 % in those from subjects on triflusal (P < 0.005). The percentage of the subendothelial surface covered by platelets was reduced by 23.3 % after treatment with ASA, mainly due to inhibition of aggregates (75.2 %), and by 29.9 % after treatment with triflusal, mainly due to inhibition of aggregates (89.6 %) and of adhesion (25 %). The subendothelial surface covered by activated platelets (adhesions and thrombi) showed 32.5 % inhibition after treatment with triflusal and 11.6 % after treatment with ASA (P < 0.043 vs, triflusal). In the in vitro experiments, 10 mu mol . l(-1) triflusal did not modify the percentage of the subendothelium covered by platelets. HTB 1 mmol . l(-1) inhibited adhesion (26 %) and aggregates (18 %). We conclude that HTB participates in the ex vivo effects of triflusal on the platelet-subendothelium interaction.