Tranexamic Acid and Systemic Complement Activation in Traumatic Brain Injury Patients

Area of Science:

• Trauma research
• Neuroscience
• Immunology

Background:

• Traumatic brain injury (TBI) is a significant cause of mortality.
• Pre-hospital tranexamic acid (TXA) administration shows a mortality benefit in TBI patients.
• The mechanism behind TXA's mortality benefit is not fully understood, as it doesn't reduce brain bleed size.

Purpose of the Study:

• To investigate the effect of pre-hospital TXA on complement activation in TBI patients.
• To explore potential mechanisms of TXA's benefit beyond hemostasis.

Main Methods:

• A randomized pre-hospital trial involving 40 adult TBI patients receiving either TXA or placebo.
• Plasma analysis at presentation, 6, and 24 hours for complement activation/regulatory markers, coagulation, and plasmin generation.
• Utilized complement multiplex assays, ELISA, and clinical laboratory testing.

Main Results:

• TXA significantly reduced terminal complement complex (sC5b-9) and C5a levels.
• Factor H, a complement regulator, was preserved in the TXA group.
• D-dimer levels were significantly lower in the TXA group at 6 hours.

Conclusions:

• Pre-hospital TXA bolus appears to modulate the complement system in TBI.
• TXA may exert its beneficial effects through complement inhibition, potentially via a plasmin-mediated pathway.
• Further research is needed to confirm the plasmin-mediated mechanism and its applicability to different trauma populations.