Serum Hsp70 as an Early Predictor of Fatal Outcome after Severe Traumatic Brain Injury in Males

Severe traumatic brain injury (TBI) is associated with a 35-70% mortality rate. Biochemical markers of cellular stress/injury have been proposed to indicate outcome after head injury. Therefore, our aim was to determine whether Hsp70 could be detected in the serum of patients after severe TBI and whether serum levels of Hsp70 correlate with primary outcome in severe TBI. Twenty consecutive male patients, victims of severe TBI (GCS 3-8), were enrolled in this prospective study. Clinical outcome variables of severe TBI comprised: survival, time for ICU discharge, and neurological assessment using the Glasgow Outcome Scale (GOS) at the ICU discharge. Venous blood samples were taken at admission in the ICU (study entry), 24 h later, and 7 days later. A control group consisting of eight healthy male volunteers was also included. Serum Hsp70 levels were measured by an enzyme-linked immunosorbent assay. Mean serum Hsp70 concentrations were significantly increased in the TBI (97.6, 48.1, and 39.2 ng/mL, at study entry, 24 h later, and 7 days later, respectively) compared with the control group (12.2 ng/mL). Severe TBI was associated with a 50% mortality rate. On study entry (mean time 10.8 h after injury), a higher proportion of patients with fatal outcome had elevated serum Hsp70 (mean 143.5 ng/mL) concentrations when compared with survivors (mean 51.6 ng/mL). There was a significant correlation between higher initial serum Hsp70 concentrations and fatal outcome. The sensitivity of serum Hsp70 predicting mortality according to the cutoff of 62 ng/mL is 70% within 20 h after injury. Increased serum Hsp70 levels may constitute an early predictor of unfavorable outcome in severe TBI in males.