tPA-S⁴⁸¹A blocks development of a systemic coagulopathy. Immediately after CHI, mice were given saline (Cont) or saline containing tPA-S⁴⁸¹A (1 mg/kg), tranexamic acid (TA; 150 mg/kg), aprotinin (Ap; 1 mg/kg), or TA plus Ap. tPA-S⁴⁸¹A inhibited formation of d-dimers (DD) (A) and development of thrombocytopenia (B) post-CHI. (C) tPA-S⁴⁸¹A attenuated the post-TBI rise in CSF d-dimers. d-dimers in the CSF increased post TBI in WT mice but to a lesser extent than in the plasma (compare panels C and A). Plasma and CSF d-dimers and platelet counts were measured 2 hours later. The mean ± 2 SD of 3 experiments performed in 6 to 8 mice is shown.