Platelet-derived MPs are internalized by HUVEC. (A-B) HUVEC were incubated for the indicated periods of time (t), with fluorescent-labeled MPs at an HUVEC:MPs ratio of 1:100, and an MP uptake was visualized by confocal microscopy (×63 objective) (upper panels). Cell morphology was visualized using differential interference contrast (DIC) (lower panels). (B) HUVEC were incubated with fluorescently labeled MPs for 3 hours, and MP uptake was visualized by confocal microscopy after a 24- or 48-hour washout period (upper panels). The images are representative of 3 independent experiments.