Small aggregates of platelets can be detected sensitively by a flow cytometer equipped with an imaging device: mechanisms of epinephrine-induced aggregation and antiplatelet effects of beraprost.
BACKGROUND
Although cross-talks between platelets and other blood cells are important in vivo, laboratory platelet aggregation tests have been performed mainly with the use of platelet-rich plasma (PRP) as samples. Methods that enable an efficient and sensitive detection of platelet aggregates in whole blood are being developed.


METHODS
A flow cytometer equipped with an imaging device, the flow imaging cytometer 2 (FIC2), was used to detect platelet aggregates in whole blood.


RESULTS
The FIC2 provides a resolution that is high enough to differentiate platelet aggregates from single platelets or other blood cells. Epinephrine elicited platelet aggregate formation in hirudin plus argatroban-treated whole blood, but not in PRP. The reconstitution study revealed that a small amount of adenosine diphosphate (ADP) from erythrocytes may play an important role in epinephrine-induced platelet aggregation (in whole blood), through mediation of P2Y1 receptors. When the inhibitory effect of beraprost, an antiplatelet agent, on platelet aggregation was assessed, analysis of whole blood samples with FIC2 proved to be the most sensitive among the methods available.


CONCLUSIONS
FIC2 is a promising device for detection of platelet aggregates in whole blood, with wide basic and clinical applications.
Satoh
Kaneo
K
Department of Laboratory Medicine, Yamanashi Medical University, Tamaho, Nakakoma, Yamanashi, Japan.
Yatomi
Yutaka
Y
Kubota
Fumio
F
Ozaki
Yukio
Y
D004837:Epinephrine / Q000494:pharmacology; D011464:Epoprostenol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004912:Erythrocytes / Q000166:cytology / Q000502:physiology; D005434:Flow Cytometry / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D010974:Platelet Aggregation / Q000187:drug effects* / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013566:Sympathomimetics / Q000494:pharmacology
D010975:Platelet Aggregation Inhibitors; D013566:Sympathomimetics; C048081:beraprost; D011464:Epoprostenol; D004837:Epinephrine