Decreased Cerebrospinal Fluid Apolipoprotein E After Subarachnoid Hemorrhage. Correlation With Injury Severity and Clinical Outcome

Background and Purpose— The apolipoprotein E (APOE) e4 allele has been associated with unfavorable outcome after subarachnoid hemorrhage (SAH), suggesting that apoE plays an important role in the response of the brain to SAH. We determined the concentration of apoE in the cerebrospinal fluid (CSF) of patients with SAH and a control group to test the hypothesis that alterations in CSF apoE reflect the response of the brain to SAH and are correlated with the severity of injury and outcome. Methods— ApoE and S100B (a marker of brain injury) were measured by ELISA in CSF from a non–brain-injured control group and patients with SAH. The severity of SAH was determined from the Glasgow Coma Scale, and the clinical outcome was determined from the Glasgow Outcome Scale. Results— In contrast to increased CSF concentration of S100B, CSF apoE concentration was significantly lower in patients after SAH than in control subjects (Mann-Whitney test, P<0.0001). SAH patients with more severe injury and less favorable outco...