Serum biomarkers for experimental acute spinal cord injury: rapid elevation of neuron-specific enolase and S-100beta.
OBJECTIVE
We evaluated whether serum levels of neuron-specific enolase (NSE) and S-100beta protein are biomarkers for traumatic injury in an animal model of spinal cord injury (SCI).


METHODS
Enzyme-linked immunosorbent assay serum measurements of NSE and S-100beta and assays of serum protein were compared at 6 and 24 hours after a graded contusive SCI (150 or 200 kdyn IH impactor injury (Infinite Horizons, L.L.C., Lexington, KY) or sham laminectomy at T9 in 30 female Sprague-Dawley rats. Serum from control animals was also analyzed.


RESULTS
Increases in serum levels of NSE were observed for 200-kdyn (3.1-fold, P < 0.001) and 150-kdyn (2.3-fold, P < 0.001) injury groups at 6 hours after injury, which decreased by 73.7% (P < 0.001) and 65.2% (P < 0.001) at 24 hours after SCI, respectively; the levels were still greater than in sham animals (P < 0.001, P = 0.001). The 200- and 150-kdyn injury groups were not different at either time point. S-100beta serum levels increased at 6 hours in the 200-kdyn injury group (P < 0.05), and no differences from sham levels were seen at 24 hours. No differences in total protein concentrations were observed between the injury and control groups.


CONCLUSIONS
Present data suggest that NSE and S-100beta serum levels may be useful experimental tools for the acute measurement of tissue loss after SCI. Despite significant shortcomings, NSE and S-100beta serum measurements in acute SCI patients with clinically defined functional deficits should allow comparisons with well-characterized SCI animal models. Future efforts to develop biomarkers that predict functional outcomes in the acute phase should focus on axon-specific proteins as markers of secondary axonal loss and regeneration.
Loy
David N
DN
Kentucky Spinal Cord Injury Research Center, and Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA.
Sroufe
Angela E
AE
Pelt
Jennifer L
JL
Burke
Darlene A
DA
Cao
Qi-Lin
QL
Talbott
Jason F
JF
Whittemore
Scott R
SR
D000208:Acute Disease; D000818:Animals; D015415:Biomarkers / Q000097:blood; D005260:Female; D009414:Nerve Growth Factors / Q000097:blood*; D010751:Phosphopyruvate Hydratase / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood*; D013119:Spinal Cord Injuries / Q000097:blood*; D013997:Time Factors
D015415:Biomarkers; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D010751:Phosphopyruvate Hydratase