Summary
Ticagrelor is an antagonist of the platelet P2Y12 receptor for ADP, approved for the prevention of thromboembolic events in patients
with acute coronary syndrome. Previous studies showed that ticagrelor has no significant
activity versus P1 receptors for adenosine and other known P2Y receptors, with the
exception of P2Y13, which was not tested. The P2Y12 antagonist cangrelor has been shown to also inhibit P2Y13 and to decrease the P2Y13-regulated capacity of megakaryocytes to produce pro-platelets. We tested whether
or not ticagrelor inhibits P2Y13 signalling and function. The in vitro effects of ticagrelor, its active (TAM) and inactive (TIM) metabolites, cangrelor
and the P2Y13 antagonist MRS2211 were tested in two experimental models: 1) a label-free cellular
response assay in P2Y13-transfected HEK293 T-REx cells; and 2) pro-platelet formation by human megakaryocytes
in culture. Ticagrelor, TAM, cangrelor and MRS2211, but not TIM, inhibited the cellular
responses in P2Y13-transfected cells. In contrast, only MRS2211 and cangrelor, confirming previous results,
inhibited pro-platelet formation by megakaryocytes in vitro. The platelet count of patients randomised to treatment with ticagrelor in the PLATO
trial did not change during treatment and was comparable to those of patients randomised
to clopidogrel. In conclusion, ticagrelor and TAM act as P2Y13 antagonists in a transfected cell system in vitro but this does not translate into any impact on pro-platelet formation in vitro or altered platelet count in patients.
Keywords
Ticagrelor - P2Y
12
- P2Y
13
- megakaryocytes - platelets