Objective: Traumatic brain injury (TBI) is associated with cerebrovascular dysfunction and changes of the blood-brain barrier (BBB) function. Although knowledge about the function of the BBB would be of high interest, non-invasive neurodiagnostic tools are still lacking. In this context it has been shown, that the astrocytic protein S100-B is a significant parameter for neuronal damage. However, there is only poor knowledge about the dynamics of S100-B in cerebrospinal fluid (CSF) and serum of patients with severe TBI. Therefore, the aim of this study was to analyze intrathecal and systemic concentrations of S100-B in patients with severe TBI in correlation to the development of progressive intracranial hemorrhage (PIH) as well as to the CSF/serum albumin ratio (Q subsetalb), as functional parameter of the BBB.
Patients and methods: In patients, suffering from severe TBI (GCS =or<8pts) and respectively healthy control patients, albumin for calculating the CSF/serum albumin ratio (Q subsetalb) as well as S100-B protein were analyzed in CSF and serum. Samples were collected immediately after placement of a ventricular catheter and 12h, 24h, 48 h and 72 h after TBI. S100-B was quantified using Elecsys S-100 superset assay (Roche superset Diagnostics; Mannheim, Germany). Volume measurements of focal mass lesions based on CT images taken during the first 72 h after TBI were obtained according to the Cavalieri's Direct Estimator method.
Results: 21 TBI-patients and respectively 10 healthy controls were enrolled. In patients exhibiting a mean ICP >15 mmHg (n = 15) CSF levels of S100-B were significantly increased on admission (819 +/- 78 pg/ml) compared to patients with ICP =or<15 mmHg (n = 6, 175 +/- 12 pg/ml) as well as to the control group (n = 10, 0.8 +/- 0.09 pg/ml). In the group with ICP >15 mmHg 8 patients developed PIH A positive correlation was found between CSF S100-B and ICP (r2 = 0.925, p<0.001). Furthermore a positive correlation between serum S100-B and Q subsetalb was found for each sampling point (r superset2 = 0.793, p<0.001).
Conclusions: The cerebrospinal and serum concentration of S100-B in patients with severe TBI was evaluated. Monitoring cerebrospinal S100-B might help to prospectively identify patients with PIH.