Cerebrospinal fluid biomarkers of glial and axonal injury in cervical spondylotic myelopathy

A future blood test for acute traumatic spinal cord injury

Acute spinal cord injury (SCI) requires prompt diagnosis and intervention to minimize the risk of permanent neurologic deficit. Presently, SCI diagnosis and interventional planning rely on magnetic resonance imaging (MRI), which is not always available or feasible for severely injured patients. Detection of disease-specific biomarkers in biofluids via liquid biopsy may provide a more accessible and objective means of evaluating patients with suspected SCI. Cell-free DNA, which has been used for diagnosing and monitoring oncologic disease, may detect damage to spinal cord neurons via tissue-specific methylation patterns. Other types of biomarkers, including proteins and RNA species, have also been found to reflect neuronal injury and may be included as part of a multi-analyte assay to improve liquid biopsy performance. The feasibility of implementing liquid biopsy into current practices of SCI management is supported by the relative ease of blood sample collection as well as recent advancements in droplet digital polymerase chain reaction technology. In this review, we detail the current landscape of biofluid biomarkers for acute SCI and propose a framework for the incorporation of a putative blood test into the clinical management of SCI.

Human spinal cord tissue is an underutilised resource in degenerative cervical myelopathy: findings from a systematic review of human autopsies

STUDY DESIGN

Systematic review.

BACKGROUND

Although degenerative cervical myelopathy (DCM) is the most prevalent spinal cord condition worldwide, the pathophysiology remains poorly understood. Our objective was to evaluate existing histological findings of DCM on cadaveric human spinal cord tissue and explore their consistency with animal models.

METHODS

MEDLINE and Embase were systematically searched (CRD42021281462) for primary research reporting on histological findings of DCM in human cadaveric spinal cord tissue. Data was extracted using a piloted proforma. Risk of bias was assessed using Joanna Briggs Institute critical appraisal tools. Findings were compared to a systematic review of animal models (Ahkter et al. 2020 Front Neurosci 14).

RESULTS

The search yielded 4127 unique records. After abstract and full-text screening, 19 were included in the final analysis, reporting on 150 autopsies (71% male) with an average age at death of 67.3 years. All findings were based on haematoxylin and eosin (H&E) staining. The most commonly reported grey matter findings included neuronal loss and cavity formation. The most commonly reported white matter finding was demyelination. Axon loss, gliosis, necrosis and Schwann cell proliferation were also reported. Findings were consistent amongst cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. Cavitation was notably more prevalent in human autopsies compared to animal models.

CONCLUSION

Few human spinal cord tissue studies have been performed. Neuronal loss, demyelination and cavitation were common findings. Investigating the biological basis of DCM is a critical research priority. Human spinal cord specimen may be an underutilised but complimentary approach.

Cerebrospinal fluid biomarkers of white matter injury and astrogliosis are associated with the severity and surgical outcome of degenerative cervical spondylotic myelopathy

BACKGROUND CONTEXT

Degenerative cervical spondylotic myelopathy (DCM) is the commonest form of spinal cord injury in adults. However, a limited number of clinical reports have assessed the role of biomarkers in DCM.

PURPOSE

We evaluated cerebrospinal fluid (CSF) biomarkers in patients scheduled for DCM surgery and hypothesized that CSF biomarkers levels (1) would reflect the severity of preoperative neurological status; and (2) correlate with radiological appearance; and (3) correlate with clinical outcome.

STUDY DESIGN/SETTING

Prospective clinical and laboratory study.

PATIENT SAMPLE

Twenty-three DCM patients, aged 66.4±12.8 years and seven controls aged 45.4±5.3 years were included.

OUTCOME MEASURES

The American Spinal Injury Association Impairment Scale, the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire and EuroQol 5-dimensions were assessed preoperatively and at 3 months post-surgery.

METHODS

We measured preoperative biomarkers (glial fibrillary acidic protein [GFAP], neurofilament light [NFL], phosphorylated neurofilament-H [pNF-H] and Ubiquitin C-terminal hydrolase L1) in CSF samples collected from patients with progressive clinical DCM who underwent surgical treatment. Biomarker concentrations in DCM patients were compared with those of cervical radiculopathy controls.

RESULTS

The median symptom duration was 10 (interquartile range 6) months. The levels of GFAP, NFL, pNF-H, Ubiquitin C-terminal hydrolase L1 were significantly higher in the DCM group compared to controls (p=.044, p=.002, p=.016, and p=.006, respectively). Higher pNF-H levels were found in patients with low signal on T1 Magnetic Resonance Imaging sequence compared to those without (p=.022, area under the receiver operating characteristic curve [AUC] 0.780, 95% Confidence Interval: 0.59-0.98). Clinical improvement following surgery correlated mainly with NFL and GFAP levels (p<.05).

CONCLUSIONS

Our results suggest that CSF biomarkers of white matter injury and astrogliosis may be a useful tool to assess myelopathy severity and predict outcome after surgery, while providing valuable information on the underlying pathophysiology.

Olive Polyphenol as Neuroprotective in Chronic Cervical Myelopathy Rabbit Model

BACKGROUND: Olive polyphenols are known to be an anti-oxidants and anti-inflammatory agents. AIM: The purpose of this study was to determine the potential neuroprotective effect on chronic cervical myelopathy rabbit model. METHODS: This study was divided into six groups; control negative (Sham-Operated) group, control positive 1 and 2, treatment groups 1, 2, and 3. Olive leaf extract (OLE) gives 350 mg/kg BW and spinal cord sample was taken at the compression level C5. Histopathological assessment and immunohistochemistry of neurofilaments (NF), S-100, brain derived neurotrophic factor (BDNF), and evaluation of functional motoric outcome were done before animals were terminated. RESULTS: Chronic cervical myelopathy in rabbit model causes decreased expression of NF, S-100, BDNF, and decreased motor function. Oral administration of OLE increased the expression of these biomarkers and improved motor function outcomes. DISCUSSION: These findings indicate that OLE may be effective in protecting chronic cervical myelopathy in rabbit model.