Time-dependent changes in serum biomarker levels after blast traumatic brain injury.

Neuronal and glial proteins detected in the peripheral circulating blood after injury can reflect the extent of the damage caused by blast traumatic brain injury (bTBI). The temporal pattern of their serum levels can further predict the severity and outcome of the injury. As part of characterizing a large-animal model of bTBI, we determined the changes in the serum levels of S100B, neuron-specific enolase (NSE), myelin basic protein (MBP), and neurofilament heavy chain (NF-H). Blood samples were obtained prior to injury and at 6, 24, 72 h, and 2 weeks post-injury from animals with different severities of bTBI; protein levels were determined using reverse phase protein microarray (RPPM) technology. Serum levels of S100B, MBP, and NF-H, but not NSE, showed a time-dependent increase following injury. The detected changes in S100B and MBP levels showed no correlation with the severity of the injury. However, serum NF-H levels increased in a unique, rapid manner, peaking at 6 h post-injury only in animals exposed to severe blast with poor clinical and pathological outcomes. We conclude that the sudden increase in serum NF-H levels following bTBI may be a useful indicator of injury severity. If additional studies verify our findings, the observed early peak of serum NF-H levels can be developed into a useful diagnostic tool for predicting the extent of damage following bTBI.