Elevated levels of phosphorylated neurofilament heavy subunit in the cerebrospinal fluid of patients with lumbar spinal stenosis: preliminary findings

Diagnostic utility of neurofilament markers for MND is limited in restricted disease phenotype and for differentiation from compressive myeloradiculopathies

Misdiagnosis is frequent in early motor neuron disease (MND), typically compressive radiculopathy, or in patients with restricted MND phenotype. In this retrospective, single tertiary centre study, we measured levels of neurofilament light (NfL) and phosphorylated neurofilament heavy (p-NfH) chain in cerebrospinal fluid (CSF) and of p-NfH in serum with commercially available ELISA kits and assessed their respective diagnostic performance as a marker of MND. The entire study population (n = 164) comprised 71 MND patients, 30 patients with compressive myelo- or radiculopathy, and 63 disease controls (DC). Among MND patients, we specified subgroups with only lower motoneuron involvement (MND-LMN, n = 15) and with confounding nerve roots or spinal cord compression (MND-C, n = 18), representing clinical diagnostic pitfalls. MND-LMN displayed significantly lower CSF NfL (p = 0.003) and p-NFH (p = 0.017), but not serum p-NfH (p = 0.347) levels compared to other MND patients (n = 56). The discriminative ability (area under the curve-AUC) of both CSF Nfs towards all MND patients was comparable to each other but significantly higher than that of p-NfH in serum (ps < 0.001). AUC of both CSF Nfs between MND-LMN and DC and also between MND-C and myelo-/radiculopathies were reduced, as compared to AUC between other MND and DC or myelo-/radiculopathies, respectively. Our results suggest that both Nfs in CSF represent a reliable diagnostic marker in a general MND population, fulfilling Awaji criteria. As for diagnostic pitfalls, and also for p-NfH in serum, their discriminative ability and, therefore, clinical utility appears to be limited.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lumbar spinal stenosis, 2021 - Secondary publication

BACKGROUND

The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine.

METHODS

The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members.

RESULTS

Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided.

CONCLUSIONS

The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS.

Lysophosphatidic acid is associated with neuropathic pain intensity in humans: An exploratory study

The underlying mechanisms of neuropathic pain remain to be elucidated. Basic animal research has suggested that lysophosphatidic acids, which are bioactive lipids produced by autotaxin from lysophosphatidylcholine, may play key roles in the initiation and maintenance of neuropathic pain. Here, we investigated the clinical relevance of lysophosphatidic acids signaling on neuropathic pain in humans. Eighteen patients who had been diagnosed with neuropathic pain with varied etiologies participated in the study. Cerebrospinal fluid samples were obtained by lumbar puncture and the concentrations of 12 species of lysophosphatidic acids and lysophosphatidylcholine, autotaxin, and the phosphorylated neurofilament heavy subunit were measured. Pain symptoms were assessed using an 11-point numeric rating scale and the Neuropathic Pain Symptom Inventory regarding intensity and descriptive dimensions of neuropathic pain. The total lysophosphatidic acids were significantly associated with both pain intensity and symptoms. 18:1 and 20:4 lysophosphatidic acids in particular demonstrated the most correlations with dimensions of pain symptoms. Autotaxin and the phosphorylated neurofilament heavy subunit showed no association with pain symptoms. In conclusions, lysophosphatidic acids were significantly associated with pain symptoms in neuropathic pain patients. These results suggest that lysophosphatidic acids signaling might be a potential therapeutic target for neuropathic pain.

Axonal damage is remarkable in patients with acutely worsening symptoms of compression myelopathy: biomarkers in cerebrospinal fluid samples

PURPOSE

To determine levels of biomarkers reflecting damage to axon, myelin, astrocytes, and neuron in cerebrospinal fluid (CSF) of patients with cervical compression myelopathy.

METHODS

We collected 69 CSF samples from patients before spinal surgery for acutely worsening compression myelopathy (AM, 20), chronic compression myelopathy (CM, 20), and lumbar canal stenosis (LCS 29; control). We measured levels of phosphorylated neurofilament subunit H (pNF-H), tau (reflecting axonal damage), myelin basic protein (MBP) (reflecting demyelination), S100b (reflecting astrocyte damage), and neuron-specific enolase (NSE) (reflecting neuronal damage). Change of neurological function by surgery was determined using a Japanese Orthopaedic Association (JOA) score for cervical myelopathy.

RESULTS

Significantly higher levels of pNF-H were detected in AM compared with those in either CM or LCS (P < 0.01). Significantly higher levels of tau were detected in AM compared with those in CM (P < 0.05). Levels of MBP were undetectable in almost all the patients. Levels of S100b were equivalent in the three groups. Levels of NSE in AM and CM were significantly lower than those in LCS (P < 0.01). The recovery rate of JOA score was significantly greater for patients with AM than CM. We found a positive correlation between pNF-H and recovery of JOA score (r = 0.381, P = 0.018).

CONCLUSION

The present results suggest that axonal damage is remarkable compared with demyelination, astrocytic, and neuronal damage in AM. Better clinical outcome in AM with high CSF levels of pNF-H indicates that axonal compensatory plasticity in spinal cord is preserved, and pNF-H can be predictive of good surgical outcome for AM. These slides can be retrieved under Electronic Supplementary Material.