Effects of dipyridamole and aspirin on shear-induced platelet aggregation in whole blood and platelet-rich plasma.
BACKGROUND
Shear-induced platelet aggregation (SIPA) is an important mechanism of thrombosis at arterial bifurcations or stenotic lesions.


METHODS
We investigated the in vitro effects of dipyridamole (DP) and acetylsalicyclic acid (ASA) on SIPA in whole blood and platelet-rich plasma (PRP).


RESULTS
In whole blood, DP 20 microM significantly inhibited SIPA, while DP 5 microM or ASA 5 or 20 microM did not. SIPA in whole blood was, however, significantly inhibited by the combination of 5 or 20 microM of DP and ASA. SIPA in PRP was not inhibited by any concentration of DP or ASA, alone or in combination.


CONCLUSIONS
These results suggest that DP has an effect on red blood cells and that ASA enhances the inhibitory effect of DP on SIPA in whole blood. These effects may be related to the additive effect of combination therapy with DP and ASA on stroke prevention.
Nakamura
T
T
Department of Neurology, Neurological Institute, Tokyo Women's Medical University, Tokyo, Japan. tnakamur@nij.twmu.ac.jp
Uchiyama
S
S
Yamazaki
M
M
Iwata
M
M
D000328:Adult; D001120:Arginine / Q000494:pharmacology; D001241:Aspirin / Q000494:pharmacology*; D001769:Blood / Q000187:drug effects; D004176:Dipyridamole / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D013314:Stress, Mechanical
D010975:Platelet Aggregation Inhibitors; D004176:Dipyridamole; D001120:Arginine; D001241:Aspirin