Page 203 - Haematologica May 2022

Letters to the Editor
bioenergetics by the uncoupler and inhibitors accounts for differences in their impact on platelet responses. Concurrent inhibition of both mitochondrial respiration and glycolysis has been found to impede platelet aggre- gation.1,2,4 This prompted us to hypothesize that, CCCP
could be compromising both mitochondrial and glycolyt- ic ATP generation, thereby leading to impaired platelet responses. Intriguingly, neither antimycin/oligomycin nor CCCP had any significant effect on cellular ATP level in platelets (Figure 3A). Sustained ATP levels suggest
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Figure 2. Effects of pre-treatment with mitochondrial inhibitors (antimycin, oligomycin) or an uncoupler (CCCP) on platelet thrombus formation. Washed human platelets pretreated with antimycin (2 μg/mL), oligomycin (10 μg/mL), CCCP (100 μM) or vehicle (control) were labeled with calcein-AM (Molecular Probes #C3100MP) and perfused over an immobilized collagen matrix for 5 min in a microfluidics flow chamber at a shear rate of 1500 s-1. (A-C) Representative images of platelet accumulation after 5 min of perfusion of human platelets with treatments as indicated in the presence of vehicle (A), ticagrelor (1 μM) (B) or tirofiban (100 ng/mL) (C). (D-L) Corresponding bar diagrams representing total surface area covered by platelet thrombi after 5 min of perfusion on the col- lagen matrix. Each dot represents an independent observation. Data are presented as mean ± standard error of mean. *P<0.05 with respect to vehicle-treated sample. Statistical significance of difference of means was tested by a multiple paired Student t-test.
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