CTRP-1 blocks adhesion of platelets on a collagen type I–coated surface at high shear. CTRP-1 does not affect rolling of platelets on a VWF-coated surface. In A and B, citrated whole human blood was incubated with either vehicle alone (A) or with 20 μg/mL CTRP-1 (B) and was perfused over collagen type I–coated coverslips through a flow chamber at 50 dyne/cm². In C and D, citrated whole human blood was incubated with either vehicle alone (C) or with 20 μg/mL CTRP-1 (D) and was perfused over VWF-coated coverslips through the flow chamber at 50 dyne/cm². The pictures shown are the initial frames of brief movies (Videos S1-S4; see the Supplemental Videos link at the top of the online article, at the Blood website) and are representative of repeated experiments.