Blast exposure results in tau and neurofilament light chain changes in peripheral blood

Objectives: To evaluate how blast exposure impacts peripheral biomarkers in military personnel enrolled in 10-day blast training. Methods: On day 7, 21 military personnel experienced peak overpressure <2 pounds per square inch (psi); while 29 military personnel experienced peak overpressure ≥5 psi. Blood samples were collected each day to measure changes in amyloid beta (Aβ), neurofilament light chain (NFL), and tau concentrations. Results: Within 24 hours following exposure ≥5 psi, the ≥5 psi group had lower Aβ42 (p = .004) and NFL (p < .001) compared to the <2 psi group and lower Aβ42 (9.35%) and NFL (22.01%) compared to baseline. Twenty-four hours after ≥5 psi exposure, the ≥5 psi group had lower tau (p < .001) and NFL (p < .001) compared to the <2 psi group and baseline. Seventy-two hours after exposure ≥5 psi, tau increased in the ≥5 psi group compared to the <2 psi group (p = .02) and baseline. The tau:Aβ42 ratio 24 hours after blast (p = .012), and the Aβ40:Aβ42 ratio 48 hours after blast (p = .04) differed in the ≥5 psi group compared to the <2 psi group. Conclusions: These findings provide an initial report of acute alterations in biomarker concentrations following blast exposure.