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

Peripheral blood RNA biomarkers can predict lesion severity in degenerative cervical myelopathy

JOURNAL/nrgr/04.03/01300535-202506000-00027/figure1/v/2024-08-05T133530Z/r/image-tiff Degenerative cervical myelopathy is a common cause of spinal cord injury, with longer symptom duration and higher myelopathy severity indicating a worse prognosis. While numerous studies have investigated serological biomarkers for acute spinal cord injury, few studies have explored such biomarkers for diagnosing degenerative cervical myelopathy. This study involved 30 patients with degenerative cervical myelopathy (51.3 ± 7.3 years old, 12 women and 18 men), seven healthy controls (25.7 ± 1.7 years old, one woman and six men), and nine patients with cervical spondylotic radiculopathy (51.9 ± 8.6 years old, three women and six men). Analysis of blood samples from the three groups showed clear differences in transcriptomic characteristics. Enrichment analysis identified 128 differentially expressed genes that were enriched in patients with neurological disabilities. Using least absolute shrinkage and selection operator analysis, we constructed a five-gene model (TBCD, TPM2, PNKD, EIF4G2, and AP5Z1) to diagnose degenerative cervical myelopathy with an accuracy of 93.5%. One-gene models (TCAP and SDHA) identified mild and severe degenerative cervical myelopathy with accuracies of 83.3% and 76.7%, respectively. Signatures of two immune cell types (memory B cells and memory-activated CD4+ T cells) predicted levels of lesions in degenerative cervical myelopathy with 80% accuracy. Our results suggest that peripheral blood RNA biomarkers could be used to predict lesion severity in degenerative cervical myelopathy.

Fluid biomarkers for cervical spondylotic myelopathy

INTRODUCTION

There is a scarcity of literature exploring fluid-based biomarkers that have the potential to provide deeper insights into the cellular mechanisms underlying cervical spondylotic myelopathy (CSM) symptom presentation and postoperative recovery. This systematic review synthesized the literature on invasive, fluid-based biomarkers and their clinical significance with CSM.

MATERIALS AND METHODS

A comprehensive search strategy was developed for concepts of biomarkers and CSM. Retrieved results underwent title, abstract, and full-text screening with inclusion criteria being original research including animal or human subjects affected by CSM/compression myelopathy that investigated the relationship between a fluid-based biomarker and CSM. Risk-of-bias was reported using the OHAT Risk of Bias Rating Tool.

RESULTS

The search strategy resulted in 191 unique manuscripts, with 20 meeting the predetermined inclusion/exclusion criteria, included in final analysis. Of these, 15 (75.0%) were human studies, two (10.0%) were animal studies, and three studies (15.0%) included both human and animal subjects. Across human studies, the fluid utilized for biomarker assessment was blood, (N = 8, 44.4%), cerebrospinal fluid (CSF) (N = 9, 50.0%), and both blood and CSF (N = 1, 5.6%). The three most common biomarkers assessed across human studies were NSE (N = 4, 22.2%), S100b (N = 4, 22.2%), and pNF-H (N = 4, 22.2%). Risk of bias due to inadequate comparison groups was present in three human studies (16.7%) and two animal studies (40%).

CONCLUSIONS

This comprehensive systematic review identified several associations between blood and CSF-based neural, glial, and inflammatory biomarkers and CSM. However, the vast heterogeneity across studies renders it difficult to draw definitive conclusions. Future research within larger, prospective patient cohorts is needed to fully elucidate the utility these biomarkers may hold in the clinical evaluation of patients with CSM.

Noninvasive Skin Autofluorescence of Advanced Glycation End Products in Patients with Degenerative Cervical Myelopathy

OBJECTIVE

To clarify the association between skin autofluorescence of advanced glycation end products (AGEs) and clinical outcomes and pain in patients with degenerative cervical myelopathy (DCM).

METHODS

Consecutive patients with DCM were prospectively enrolled. AGEs assessed by skin autofluorescence (the AGE score) were examined at the middle fingertip in eligible patients. Patients were divided into lower AGE score (AGE-L) and higher AGE score (AGE-H) groups based on a cutoff AGE score of 0.54. Demographic data, laboratory data, maximum spinal cord compression, clinical outcomes, such as European Quality of Life-5 Dimensions, Neck Disability Index, and Japanese Orthopaedic Association score, and Numerical Rating Scale (NRS) score for neck, arm, hand, leg, and foot pain were compared between the two groups. Multiple linear regression analysis was performed to assess the association between the AGE score and the NRS score for pain in the lower limbs.

RESULTS

Of the 263 patients, 93 were included in this study (41 with the AGE-L group and 52 with the AGE-H group). Demographic data, laboratory data, maximum spinal cord compression, and clinical outcomes were comparable between the two groups. The AGE-H group had significantly higher NRS scores for leg and foot pain than the AGE-L group. Multiple linear regression analysis revealed that higher AGE scores were significantly associated with more severe pain in the lower limbs in patients with DCM.

CONCLUSIONS

Noninvasive skin autofluorescence of AGEs may be a useful biomarker for pain symptoms in the lower limbs in patients with DCM.

Metabolic changes of thalamus assessed by 1H-MRS spectroscopy in patients of cervical spondylotic myelopathy following decompression surgery

Objective

To assess the changes of thalamic metabolites before and after surgery in patients with Cervical Spondylotic Myelopathy (CSM) using Hydrogen Proton Magnetic Resonance Spectroscopy (1H-MRS) and to investigate its association with improvement in neurological function.

Methods

Forty-eight CSM patients who underwent cervical decompression surgery from December 2022 to June 2023 were included, and 33 healthy volunteers were recruited. All subjects underwent bilateral thalamic 1H-MRS scans before the surgical procedure, and subsequently again 6 months later. Neurological function was assessed pre-operatively and post-operatively (6 months) in all patients with CSM using the modified Japanese Orthopedic Association (mJOA). The changes of mJOA (ΔmJOA = postoperative mJOA-preoperative mJOA) were employed as an indicator of neurological improvement. The pre- and postoperative metabolic ratio of N-acetylaspartate/creatine (NAA/Cr), choline/creatine (Cho/Cr), myo-inositol/creatine (mI/Cr), glutamate and glutamine complex/creatine (Glx/Cr) were statistically compared in CSM patients and healthy controls (HCs). A correlation analysis was conducted to determine the relationship between alterations in pre- and postoperative metabolite ratios (ΔNAA/Cr, ΔCho/Cr, ΔmI/Cr, ΔGlx/Cr) and ΔmJOA.

Results

Compared to the HCs, patients with CSM showed significantly lower pre- and post-operative NAA/Cr (Z = -4.235, p < 0.001; Z = -3.184, p = 0.001), Cho/Cr (Z = -5.050, p < 0.001; (Z = -2.624, p = 0.007) and mI/Cr (Z = -3.739, p = 0.001; Z = -2.014, p = 0.044). There was no difference in Glx/Cr between patients in patients with CSM, either preoperatively or postoperatively, compared to HCs. Post-operative NAA/Cr (Z  = -2.285, p = 0.041) and mI/Cr (Z = -2.925, p = 0.021) were increased in CSM patients compared to pre-operative NAA/Cr and mI/Cr. In CSM patients, ΔmI/Cr correlated significantly with ΔmJOA (r = 0.507, p < 0.001).

Conclusion

The preliminary findings indicate that metabolites in the thalamus of CSM patients exhibit changes following surgery. Additionally, it has been demonstrated that elevated postoperative mI correlates with improvements in neurological function.

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.