Study design: A pilot cross-sectional study of patients with acute cervical spinal cord injury (SCI).
Objectives: The precise evaluation of the severity of SCI is important for developing novel therapies. Although several biomarkers in cerebrospinal fluid have been tested, few analyses of blood samples have been reported. A novel biomarker for axonal injury, phosphorylated form of the high-molecular-weight neurofilament subunit NF-H (pNF-H), has been reported to be elevated in blood from rodent SCI model. The aim of this study is to investigate whether pNF-H values in blood can serve as a biomarker to evaluate the severity of patients with SCI.
Setting: Tokyo Metropolitan Bokutoh Hospital and National Rehabilitation Center, Japan.
Methods: This study enrolled 14 patients with acute cervical SCI. Sequential plasma samples were obtained from 6 h to 21 days after injury. Patients were classified according to American Spinal Injury Association impairment scale (AIS) at the end of the follow-up (average, 229.1 days). Plasma pNF-H values were compared between different AIS grades.
Results: In patients with complete SCI, pNF-H became detectable at 12 h after injury and remained elevated at 21 days after injury. There was a statistically significant difference between AIS A (complete paralysis) patients and AIS C (incomplete paralysis) patients.
Conclusions: Plasma pNF-H was elevated in accordance with the severity of SCI and reflected a greater magnitude of axonal damage. Therefore, pNF-H is a potential biomarker to independently distinguish AIS A patients (complete SCI) from AIS C-E patients (incomplete SCI). However, further studies are required to evaluate its utility in predicting prognosis of patients in the incomplete category.