title: Serum τ protein as a potential biomarker in the assessment of traumatic brain injury.
abstract: Traumatic brain injury (TBI) is the leading cause of mortality and disabilities among all trauma cases. Following TBI, damage to axons results in τ protein hyperphosphorylation leading to microtubule instability and τ-mediated neurodegeneration. In addition, τ protein is proteolytically cleaved and is able to access the cerebrospinal fluid (CSF) and serum; thus, this protein may serve as a potential biomarker in the diagnosis of injury severity and outcome prediction. Although a limited number of studies have investigated the CSF τ protein levels after TBI, the data are divergent and conflicting, and investigations into the serum τ protein levels have yet to be conducted. Therefore, the present study aimed to examine the serum τ protein levels in the full spectrum of TBI patients on days 0-14 after TBI, using an enzyme-linked immunosorbent assay. The protein levels were compared to the initial Glasgow Coma Score (GCS) and the Extended Glasgow Outcome Scale (GOS-E), which are used to represent the injury severity and patient outcome, respectively. In total, 56 patients, including 20 patients with mild TBI (GCS, 13-15), 19 patients with moderate TBI (GCS, 9-12) and 17 patients with severe TBI (GCS, 3-8), were included in the current study. The outcome was assessed 1 year after the injury and patients were classified into the good outcome (40 cases; GOS-E, 5-8) and poor outcome groups (16 cases; GOS-E, 1-4). The results indicated that serum τ protein levels increased soon after TBI and reached a peak value at ~2 days after the injury. The serum τ protein levels were significantly higher in the severe TBI group compared with those in the mild and moderate TBI groups (P<0.0001). Univariate analysis indicated that poor outcome was significantly associated with higher serum τ protein levels on day 2 (P<0.0001). A receiver operating characteristic curve demonstrated that a τ protein level of >116.04 pg/ml on day 2 resulted in a 93.75% sensitivity and 92.50% specificity for predicting a poor outcome. Furthermore, a τ protein level of >372.1 pg/ml on day 2 yielded 100% sensitivity and 83.33% specificity for 1 year mortality in the severe TBI group. In conclusion, the present study suggests that serum τ protein may serve as a potential biomarker for evaluating the injury severity and predicting the outcome of TBI patients.
authors.affiliation: Department of Neurosurgery, Wuhan Central Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Junwen
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Wuhan Central Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Han
authors.affiliation: Department of Neurosurgery, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Songbo
authors.initials: S
authors.lastname: Guo
authors.affiliation: Department of Neurosurgery, Wuhan Central Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Wuhan Central Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Zuojun
authors.initials: Z
authors.lastname: Xiong
authors.affiliation: Department of Neurosurgery, Wuhan Central Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, Wuhan Central Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Wen
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, Wuhan Central Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430014, P.R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Liang
keywords: biomarker; outcome; traumatic brain injury; τ protein