Interaction between platelet-derived microRNAs and CYP2C19*2 genotype on clopidogrel antiplatelet responsiveness in patients with ACS.

BACKGROUND: Both platelet-derived microRNAs and the genotype of CYP2C19*2 were implicated for the variability of clopidogrel antiplatelet responsiveness. However, their interaction on the antiplatelet responsiveness of clopidogrel in patients with acute coronary syndrome (ACS) remains unknown.

METHODS: Consecutive clopidogrel-treated patients with ACS were recruited, with their antiplatelet responsiveness evaluated by the relative platelet inhibition (RI), as measured by light transmittance aggregometry (LTA) at baseline and 5days' after the maintenance treatment of clopidogrel. Extreme cases were selected according to the octiles of RI value. Expression of the microRNAs targeting the mRNAs of P2RY12 was analyzed in the platelet of the extreme cases. Genotyping of CYP2C19*2 was performed for each extreme case.

RESULTS: Among the included 272 ACS patients, 21 cases were screened as the extremely high-responders with RI>84%, and 18 as the extremely low-responders with RI<10%. Bioinformatics tools predicted the candidate microRNAs of miR-223, miR-221, and miR-21 could bind directly to the mRNA of P2RY12. Compared with the extremely low-responders, the expression of miR-223, miR-221, and miR-21 was significantly higher in the extremely high-responders (miR-223: 7.18±2.95 vs. 0.99±0.64, p=0.022; miR-221: 3.60±2.54 vs. 1.14±0.81, p=0.004; miR-21: 4.36±3.33 vs. 2.31±1.69, p=0.01). ROC curve showed ideal discriminatory power of the platelet-derived miRNAs for the prediction of clopidogrel antiplatelet responsiveness (c-index=0.70 for miR-223; c-index=0.76 for miR-221; c-index=0.79 for miR-21). After stratified by the carrier status of CYP2C19*2, the association between platelet-derived miRNAs and clopidogrel antiplatelet responsiveness could be found only in CYP2C19*2 carriers, but not in non-carriers.

CONCLUSIONS: Platelet-derived miRNAs (miR-223, miR-221 and miR-21) are independently associated with clopidogrel antiplatelet responsiveness in ACS patients. However, the association could be influenced by the interaction with CYP2C19*2 genotype.