title: Cerebrospinal fluid apolipoprotein E, calcium and cerebral vasospasm after subarachnoid hemorrhage.
abstract: Intracellular calcium (Ca++) regulation of cerebral vessels is impaired after subarachnoid hemorrhage (SAH), making secondary pathways, such as that involving apolipoprotein E, potentially more influential. To evaluate cerebrospinal fluid (CSF) apolipoprotein E and Ca++ levels as biomarkers of cerebral vasospasm, we examined changes in levels over time and apolipoprotein E (APOE) epsilon4 allele presence after SAH in individuals with and without vasospasm. We hypothesized that individuals with low apolipoprotein E levels, increased Ca++ levels and/or at least one copy of the APOE epsilon4 allele would have vasospasm. Daily samples from 50 participants, aged 18-75, with SAH were used to quantify apolipoprotein E and Ca++ levels. Vasospasm was verified using cerebral angiogram and/or elevated transcranial Dopplers in combination with clinical neurologic deterioration. Overall apolipoprotein E levels were higher in individuals with the APOE epsilon4 allele (p = .02) or angiographic vasospasm (p = .01), but there were no differences between individuals with and without symptomatic vasospasm. There were no significant changes in apolipoprotein E levels over time. Individuals with the epsilon4 allele had lower Ca++ levels (p = .02) with trends suggesting a different pattern of change over time (p = .07). CSF Ca++ levels were lower in individuals with symptomatic vasospasm (p < .01). Change in apolipoprotein E and Ca++ levels (p = .006) correlated over time regardless of genotype or vasospasm status. These findings suggest that apolipoprotein E and Ca++ may be interacting after SAH, but this interaction does not appear to influence vasospasm.
authors.affiliation: School of Nursing, University of Pittsburgh, Pennsylvania, USA. salexand@pitt.edu
authors.forename: Sheila A
authors.initials: SA
authors.lastname: Alexander
authors.forename: Mary E
authors.initials: ME
authors.lastname: Kerr
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Balzer
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.forename: Amin
authors.initials: A
authors.lastname: Kassam
authors.forename: Yookyung
authors.initials: Y
authors.lastname: Kim
authors.forename: Leslie
authors.initials: L
authors.lastname: Hoffman
authors.forename: Yvette P
authors.initials: YP
authors.lastname: Conley
mesh_terms: D000328:Adult; D001057:Apolipoproteins E / Q000134:cerebrospinal fluid*; D002118:Calcium / Q000134:cerebrospinal fluid*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013345:Subarachnoid Hemorrhage / Q000134:cerebrospinal fluid / Q000150:complications*; D020301:Vasospasm, Intracranial / Q000134:cerebrospinal fluid / Q000150:complications*
chemical_list: D001057:Apolipoproteins E; D002118:Calcium