D-dimer in suspension reduces platelet spreading on collagen and fibrin. (Ai) Glass coverslips were coated with collagen or fibrin as described in "Materials and methods." Human platelets (ptl; 20 × 109/L) were preincubated with D-dimer (100 μg/mL) before being allowed to spread on coated coverslips. Actin staining was performed on fixed platelets with Alexa-488 phalloidin. Scale bar, 5 μm. (Aii) Quantification of the surface area of platelets and the number of platelets per millimeter squared of 3 independent experiments. In each independent experiment, 5 random pictures were analyzed (100 platelets in total). The results are shown as mean ± standard deviation (SD). *P < .05, **P < .01. (B) The graph represents the competition binding assay between monomeric GPVI (100 nM) and D-dimer on collagen- or fibrin-coated surfaces. Binding in the absence of D-dimer is represented as 100%. The results are shown as mean ± SD and are representative of 3 experiments. **P < .01, ***P < .001.
