Evidence that a Panel of Neurodegeneration Biomarkers Predicts Vasospasm, Infarction, and Outcome in Aneurysmal Subarachnoid Hemorrhage

Biomarkers for neurodegeneration could be early prognostic measures of brain damage and dysfunction in aneurysmal subarachnoid hemorrhage (aSAH) with clinical and medical applications. Recently, we developed a new panel of neurodegeneration biomarkers, and report here on their relationships with pathophysiological complications and outcomes following severe aSAH. Fourteen patients provided serial cerebrospinal fluid samples for up to 10 days and were evaluated by ultrasonography, angiography, magnetic resonance imaging, and clinical examination. Functional outcomes were assessed at hospital discharge and 6–9 months thereafter. Eight biomarkers for acute brain damage were quantified: calpain-derived α-spectrin N- and C-terminal fragments (CCSntf and CCSctf), hypophosphorylated neurofilament H

A Panel of Neuron-Enriched Proteins as Markers for Traumatic Brain Injury in Humans

Surrogate markers have enormous potential for contributing to the diagnosis, prognosis, and therapeutic evaluation of acute brain damage, but extensive prior study of individual candidates has not yielded a biomarker in widespread clinical practice. We hypothesize that a panel of neuron-enriched proteins measurable in cerebrospinal fluid (CSF) and blood should vastly improve clinical evaluation and therapeutic management of acute brain injuries. Previously, we developed such a panel based initially on the study of protein release from degenerating cultured neurons, and subsequently on rodent models of traumatic brain injury (TBI) and ischemia, consisting of 14-3-3β, 14-3-3ζ, three distinct phosphoforms of neurofilament H, ubiquitin hydrolase L1, neuron-specific enolase, α-spectrin, and three calpain- and caspase-derived fragments of α-spectrin. In the present study, this panel of 11 proteins was evaluated as CSF and serum biomarkers for severe TBI in humans. By quantitative Western blotting and sandwich immunoassays, the CSF protein levels were near or below the limit of detection in pre-surgical and most normal pressure hydrocephalus (NPH) controls, but following TBI nine of the 11 were routinely elevated in CSF. Whereas different markers peaked coordinately, the time to peak varied across TBI cases from 24–96 h post-injury. In serum, TBI increased all four members of the marker panel for which sandwich immunoassays are currently available: a calpain-derived NH2-terminal α-spectrin fragment and the three neurofilament H phosphoforms. Our results identify neuron-enriched proteins that may serve as a panel of CSF and blood surrogate markers for the minimally invasive detection, management, mechanistic, and therapeutic evaluation of human TBI

Relationship between peak CSF neurodegeneration biomarker levels and neuroradiologically confirmed cerebral infarction.

<p>The mean (+/- S.E.M.) peak level of each biomarker from 3–10 days post-rupture is depicted in relation to infarction detectable by diffusion weighted MRI.</p

CSF changes in 3 neurodegeneration biomarkers after aneurysm rupture.

<p>(A) Western blot analyses of 14-3-3β, a calpain-cleaved α-spectrin COOH-terminal fragment (CCSctf), and UCH-L1 in 3 aSAH cases at the indicated times post-rupture (in days). Case 25 is representative of the subset of aSAH patients exhibiting large elevations in every neurodegeneration biomarker. Case 9, in contrast, shows a delayed increased in neurodegeneration biomarkers starting on day 5 after aneurysm rupture. Case 19 is representative of the subset of aSAH cases exhibiting consistently low or undetectable biomarker levels over the entire 10 day post-rupture period. (B) Western blot analysis of CCSctf levels 5 days post-rupture for 13 aSAH cases. Quantitative analysis (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028938#s2" target="_blank">Methods</a>) showed that CSF levels of this biomarker vary by 100-fold across patients.</p

Relationship between peak CSF neurodegeneration biomarker levels and hemorrhage severity.

<p>The mean (+/- S.E.M.) peak level of each biomarker from 3–10 days post-rupture is depicted in relation to the initial severity of the aneurysm dichotomized according to the Hunt-Hess grade.</p

Time courses for 6 CSF neurodegeneration biomarkers in relation to functional outcome and the severity of cerebral vasospasm.

<p>Long-term outcome was dichotomized to either poor (closed circles: GOS-E  = 1–4; mRS  = 4–6) or good (open boxes: GOS-E  = 5–8; mRS  = 1–3), while angiographic vasospasm was categorized as either moderate/severe (closed circles) or absent/mild (open boxes) as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028938#s2" target="_blank">Methods</a>. Mean CSF levels of each neurodegeneration biomarker at the indicated times post-aneurysm rupture (in days) are shown with the standard error of the mean. Statistically significant between-group differences (p<0.05) are identified by asterisk. In cases for which CSF samples were available at both 7 and 10 days post-rupture, the higher marker level was considered.</p

Aneurysmal subarachnoid hemorrhage patient demographics.

<p>Abbreviations: HH/F – Hunt-Hess/Fisher scale; C – Caucasian; H – Hispanic; AA – African-American.</p

Relationship between peak CSF neurodegeneration biomarker levels and long-term outcome.

<p>The mean (+/- S.E.M.) peak level of each biomarker from 3–10 days post-rupture is depicted in relation to long-term outcome dichotomized according to the Glasgow Outcome Scale - Extended.</p