Sustained release of neuron-specific enolase to serum in amateur boxers

Primary objective: We assess the potential of a panel of serum biomarkers to identify chronic neuronal injury in amateur boxers as compared to healthy controls without any history of head trauma. Research design: Observational case-control study. Methods and procedures: A panel of serum biomarkers was measured by a novel biochip array technique on the Evidence Investigator. Serum samples were taken after a 2-month period of nonparticipation in boxing. Main outcomes and results: Boxers had higher serum levels of neuron-specific enolase (NSE, median [range] 11 [2.3-41] ng/mL) than controls (4.8 [0.78-27] ng/mL, p = 0.014) but unchanged levels of the other brain damage biomarker candidates, S-100B, brain-derived neurotrophic factor and heart-type fatty acid binding protein. Conclusions: The more than doubled median serum level of NSE in boxers after an extended resting period suggests that repetitive head trauma results in sustained release of this brain-specific protein to the peripheral circulation.