Cerebrospinal fluid apolipoprotein E concentration decreases after traumatic brain injury.
The APOE epsilon4 allele has been associated with unfavorable outcome after several types of acute brain injury, yet the biological mechanisms underlying this observation are poorly understood. Postmortem and experimental brain injury studies suggest the presence of increased amounts of apolipoprotein E (apoE) within the neuropil after acute brain injury. We assayed the concentration of apolipoprotein E in the cerebrospinal fluid (CSF) of non-injured controls and patients with traumatic brain injury (TBI) to determine whether differences exist, and if these differences correlate with injury severity and clinical outcome. CSF apoE and S100B, a marker of injury severity, were measured by enzyme linked immunosorbant assay. CSF was sampled from 27 traumatic brain injury patients (mean age 32, median 25, range 16-65 years) within 3 days of injury, and 28 controls (mean age 40, median 37, range 19-73 years). The TBI patients all had a Glasgow Coma Score (GCS) of less than eight (i.e., severe head injury). Clinical outcome was determined using the Glasgow Outcome Score (GOS). The average concentration of apoE in the CSF of controls was 12.4 mg/L (95% CI: 10.5-14.3 mg/L) and in TBI patients was 3.7 mg/L (95% CI: 2.1-4.1 mg/L; Mann-Whitney: p < 0.0001). In contrast, the concentration of S100B in the CSF of TBI patients was significantly higher than that of controls (Mann-Whitney: p < 0.0001). We speculate that apoE is retained within the parenchyma of the central nervous system in response to injury where in view of previous data, it may have a protective role.
Kay
Andrew D
AD
Department of Neurosurgery, University of Glasgow, Institute of Neurological Sciences, Southern General Hospital, Glasgow, United Kingdom. adk4z@clinmed.gla.ac.uk
Petzold
Axel
A
Kerr
Mary
M
Keir
Geoff
G
Thompson
Ed J
EJ
Nicoll
James A R
JA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000418:Albumins / Q000134:cerebrospinal fluid; D001057:Apolipoproteins E / Q000134:cerebrospinal fluid*; D001930:Brain Injuries / Q000134:cerebrospinal fluid*; D002556:Cerebrospinal Fluid Proteins / Q000032:analysis; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015600:Glasgow Coma Scale; D023261:Glasgow Outcome Scale; D006801:Humans; D008297:Male; D008875:Middle Aged; D009414:Nerve Growth Factors / Q000134:cerebrospinal fluid; D011446:Prospective Studies; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000134:cerebrospinal fluid
D000418:Albumins; D001057:Apolipoproteins E; D002556:Cerebrospinal Fluid Proteins; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human