The Passage of S100B from Brain to Blood Is Not Specifically Related to the Blood-Brain Barrier Integrity

Following brain injury, S100B is released from damaged astrocytes but also yields repair mechanisms. We measured S100B in the cerebrospinal fluid (CSF) and serum (Cobas e411 electrochemiluminescence assay, Roche) longitudinally in a large cohort of patients treated with a ventricular drainage following traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH). Statistical analysis was performed with SPSS software applying the Mann-Whitney rank sum test or chi-test where appropriate. S100B in CSF and serum was significantly increased following TBI (n = 71) and SAH (n = 185) for at least one week following injury. High S100B levels in CSF and serum were inconsistent associated with outcome. The passage of S100B from CSF to blood (100(∗)serum(S100B)/CSF(S100B)) was significantly decreased although the albumin quotient suggested an “open” blood-CSF barrier. Events possibly interfering with the BBB did not affect the S100B passage (P = .591). In conclusion, we could not confirm S100B measurements to reliably predict outcome, and a compromised blood-CSF barrier did not affect the passage of S100B from CSF to serum.