MSCs adhere to ECs under shear flow. (A) MSCs from passage 9, PBMCs, or CD34⁺ HPCs (10⁶/analysis) were flushed over a HUVEC monolayer in the parallel plate flow chamber and analyzed at a calculated shear stress of 0.1 dynes/cm² (▪) or 2.0 dynes/cm² (□). Numbers of adherent cells were determined in 3 representative fields. (B) MSCs (passage 8), pregrown in medium in the presence and absence of bFGF for 7 days, were analyzed as described in panel A. The analyses were performed either with or without prestimulation of HUVECs with 10 ng/mL TNF-α for 4 to 6 hours as indicated. Values are means ± SD; n = 3.