We performed this study to observe the effects of different doses of ticagrelor and standard-dose clopidogrel on platelet reactivity and endothelial function in diabetic patients with stable coronary artery disease (CAD). Sixty type 2 diabetic patients were assigned to one-quarter standard-dose ticagrelor, half standard-dose ticagrelor, standard-dose ticagrelor and standard-dose clopidogrel groups. Light transmission aggregometry (LTA) and VerifyNow assay were used to measure platelet function. Endothelial function was assessed by measurement of flow-mediated vasodilation (FMD) and plasma von Willebrand factor (VWF) levels were detected. Enzyme-linked immunosorbent assay (ELISA) examined the Interleukin-8(IL-8) and IL-10. The results suggested that the one-quarter dose (34.0%± 14.7%), half-dose (26.9%± 11.6%) and standard-dose (17.3%± 10.3%) ticagrelor showed lower platelet aggregation rate than clopidogrel (52.8%± 18.3%; P ＜0.0001). PRU values in three ticagrelor groups were lower than that in clopidogrel group (102 (76-184)；75 (33-88)；38 (11-52) versus 194 (138-271) and；P ＜0.0001). FMD levels were higher in ticagrelor groups compared with baseline levels while lower in clopidogrel group after treatment. However, no significant differences were found in the percentage increase in the FMD between ticagrelor groups and clopidogrel group. The levels of VWF after treatment were lower than the baseline levels, but there was no statistically significant difference between ticagrelor group and clopidogrel group after treatment. The concentration of IL-8 and IL-10 were decreased in patients with half and standard-dose ticagrelor group. In conclusion, one-quarter standard-dose ticagrelor produced similar inhibitory effects on platelet aggregation as standard-dose clopidogrel in diabetic patients with stable CAD. The half standard-dose ticagrelor had a similar inhibitory effect on platelet inhibition as standard-dose ticagrelor, which was stronger than that of clopidogrel. Moreover, the half-dose ticagrelor had equal protection of endothelial function and inhibition of inflammatory factor as standard-dose ticagrelor.
Keywords: Coronary artery disease; flow-mediated vasodilation; interleukin; platelet function tests; ticagrelor; von Willebrand factor.