Figure 5.

Bambi^−/− platelets express PS normally and retain their procoagulant ability. Thrombin generation was measured in mouse citrate-anticoagulated plasma supplemented with 1pM TF, 16.6mM CaCl₂, fluorogenic substrate Z-GGR-AMC, and 4µM phospholipids (A) or PRP (10⁸/mL final concentration) (B) in the presence of corn trypsin inhibitor. Representative traces of thrombin generation in PPP (A) or PRP (B) from Bambi^+/+ (n = 4) and Bambi^−/− mice (n = 3). Thrombin generation was determined from the accumulation of fluorescent product and calculated relative to a thrombin calibrator. Each PPP and PRP sample was run in duplicate. For peak height values, see supplemental Table 3. (C) Exposure of PS was detected with Annexin V–FITC by flow cytometry using Bambi^+/+ and Bambi^−/− washed platelets stimulated with thrombin (1 U/mL), or a combination of thrombin and CRP (10 µg/mL) for 15 minutes. Data represent mean ± SEM (n = 3). Statistical analysis was performed using the unpaired Student t test (P > .05). (D) Levels of TAT complexes in the plasma of Bambi^+/+ and Bambi^−/− mice. Values are given as mean ± SEM of n = 5 animals for each group with technical replicates >2 for each animal. Statistical analysis was performed using the unpaired Student t test (P > .05). FITC, fluorescein isothiocyanate; PS, phosphatidylserine.