MSCs roll on HUVECs under shear flow. Analysis of numbers of rolling cells (A) and rolling velocities (B). MSCs (10⁶, passage 9) were flushed at different shear stresses over a HUVEC layer in the parallel plate flow chamber, and rolling cells were determined as described in “Materials and methods.” Values are means ± SD; n = 7-9. (C) Lifted frames of a video clip with 2 moving cells and one stationary adherent MSC. Values in top left corners indicate time from video start in seconds; the white horizontal scale bar represents 50 μm.