Increased serum S100β protein concentrations following severe head injury in humans: a biochemical marker of brain death?

This study investigated S100β protein as a biochemical serum marker of brain damage in severe head injury and brain death victims. Blood samples obtained from 15 patients with severe head injury admitted to the trauma intensive care unit (ICU), five patients with a diagnosis of brain death due to hemorrhage following cerebral aneurysm rupture, and five healthy individuals were investigated. The S100β protein serum concentrations were analyzed with a immunoradiometric assay kit. The 15 patients with severe head injury were followed up for 6 months. Outcome was considered either death or recovery with ICU discharge. S100β concentrations were closely related to brain damage. Among the severe head injury victims, higher S100β concentrations were detected in those patients that progressed to death. The individuals with brain death had similar mean S100β concentrations, irrespective of its cause (either trauma or vascular rupture). S100β protein is a promising serum outcome predictor for severe head injury victims and may contribute to the early diagnosis of brain death.