Summary
Prasugrel, through its active metabolite, reduces atherothrombosis and its clinical
manifestations by inhibiting platelet activation and aggregation. Platelets also contribute
to inflammation through interaction with different classes of leukocytes. We investigated
whether the inhibitory effect of prasugrel on platelets also counteract inflammatory
responses. The effect of prasugrel active metabolite, R-138727, was investigated on
platelet P-selectin expression, platelet adhesion to polymorphonuclear leukocytes
(PMN) and monocytes (MN) and Mac-1 expression in PMN and MN, in vitro, in human cells. The ex vivo effect of prasugrel administration on P-selectin, thromboxane (TXB)2 formation, platelet-PMN
conjugates and Mac-1 expression in PMN triggered by PAR-4 agonist peptide was examined
in whole blood from healthy mice as well as from mice in which an acute inflammatory
reaction was induced by treatment with endotoxin. The effect of prasugrel on inflammatory
markers in endotoxin-treated animals was also tested in vivo. R-138727 inhibited agonist-stimulated expression of platelet P-selectin, platelet-PMN
and platelet-MN adhesion and platelet-dependent Mac-1 expression in leukocytes. Addition
of aspirin did not modify the inhibitory effect elicited by R-138727. Treatment of
mice with prasugrel resulted in a profound inhibition of platelet P-selectin expression,
TXB2 production, platelet-PMN adhesion and Mac-1 expression in PMN induced by ex vivo stimulation with PAR-4 agonist peptide of whole blood from healthy or endotoxin-treated
mice. Measurement of markers revealed that prasugrel reduced TXB2 and tumour necrosis
factor-α synthesis and increased nitric oxide metabolites in endotoxin-treated mice
in vivo. In conclusion, prasugrel reduces platelet interactions with PMN and MN. Through
these effects prasugrel may curb platelet-mediated inflammatory responses.
Keywords
Inflammation - monocytes - neutrophils - platelets - prasugrel - P-selectin