Fibrin-independent thrombus contraction. Human whole blood was collected in the absence of anticoagulant (Native) (A), in the presence of the fibrin polymerization inhibitor GPRP (GPRP, 280 μM) (A), or in the presence of lepirudin (800 U/mL) (A,B), then perfused through type I collagen–coated glass microslides at 1800 s−1 for up to 5 minutes. (A) To visualize fibrin formation, whole-blood perfusion was performed in the presence of Oregon green–labeled fibrinogen (20 μg/mL). DIC and fluorescence images were captured in real-time using a Leica inverted microscope (×63 magnification). Images are taken from 1 representative of 4 independent experiments. (B) Thrombus formation and consolidation during perfusion of lepirudin-anticoagulated whole-blood was recorded in real time using DIC microscopy, and snapshots of individual thrombi at the indicated time points were obtained off-line. These images are taken from 1 representative of 12 independent experiments. The original outline of the thrombus prior to contraction is highlighted by the broken line.
