Thromb Haemost 2010; 104(04): 788-795
DOI: 10.1160/TH09-09-0622
Platelets and Blood Cells
Schattauer GmbH

TRA-418, a thromboxane A2 receptor antagonist and prostacyclin receptor agonist, inhibits platelet-leukocyte interaction in human whole blood

Mitsuko Miyamoto
1   Pharmaceutical Research Laboratories, Toray Industries, Kamakura, Japan
,
Michihiro Ohno
1   Pharmaceutical Research Laboratories, Toray Industries, Kamakura, Japan
,
Naohiro Yamada
1   Pharmaceutical Research Laboratories, Toray Industries, Kamakura, Japan
,
Atsushi Ohtake
1   Pharmaceutical Research Laboratories, Toray Industries, Kamakura, Japan
,
Teruo Matsushita
2   Department of Food Science and Technology, National Fisheries University, Shimonoseki, Japan
› Author Affiliations
Further Information

Publication History

Received: 06 September 2009

Accepted after major revision: 31 May 2010

Publication Date:
24 November 2017 (online)

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Summary

TRA-418, a compound with both thromboxane A2 receptor (TP receptor) antagonistic and prostacyclin receptor (IP receptor) agonistic activities, was synthesised in our laboratory as a new antithrombotic agent. In this study, we examined the effects of TRA-418 on platelet-leukocyte interactions in human whole blood. Platelet-leukocyte interactions were induced by U-46619 in the presence of epinephrine (U-46619 + epinephrine) or with thrombin receptor agonist peptide 1–6 (TRAP). Platelet-leukocyte interactions were assessed by flow cytometry, with examination of both platelet-neutrophil and platelet-monocyte complexes. In a control experiment, the TP receptor antagonist SQ-29548 significantly inhibited the induction of platelet-leukocyte complexes by the combination of U-46619 and epinephrine, but not TRAP-induced formation of platelet-leukocyte complexes. Conversely, the IP receptor agonist beraprost sodium inhibited platelet-leukocyte complex formation induced by both methods, although the IC50 values of beraprost sodium for U-46619 + epinephrine were at least 10-fold greater than for TRAP. Under such conditions, TRA-418 inhibited both U-46619 + epinephrine-induced and TRAP-induced platelet-leukocyte complex formation in a concentration-dependent manner, in a similar range. These results suggest that TRA-418 exerts its inhibitory effects on platelet-leukocyte interactions by acting as a TP receptor antagonist as well as an IP receptor agonist in an additive or synergistic manner. These inhibitory effects of TRA-418 on formation of platelet-leukocyte complexes suggest the compound is beneficial effects as an antithrombotic agent.