Bridging the gap-Immune cells that can repair nerves

Radiologic Predictors of Visual Outcome in Myelin Oligodendrocyte Glycoprotein-Related Optic Neuritis

PURPOSE

This study aimed to determine whether magnetic resonance imaging (MRI) biomarkers are associated with visual prognosis in myelin oligodendrocyte protein (MOG)-associated optic neuritis (ON).

DESIGN

Cross-sectional analysis.

PARTICIPANTS

Patients meeting 2023 international diagnostic criteria for MOG antibody-associated disease who were seen for first episodes of MOG-associated ON at 3 tertiary neuro-ophthalmology practices between January 2017 and July 2023 were enrolled. Patients who received < 3 months of neuro-ophthalmic follow-up and did not demonstrate visual recovery (visual acuity [VA] ≥ 20/20 and visual field mean deviation [VFMD] > -5.0 dB) during this time were excluded.

METHODS

Patients underwent contrast-enhanced, fat-suppressed MRI of the brain and orbits within 1 month of symptom onset.

MAIN OUTCOME MEASURES

The associations between radiologic biomarkers and poor VA outcome (< 20/40), incomplete VA recovery (< 20/20), and poor VFMD outcome (VFMD < -5.0 dB) were assessed using multivariable logistic regression adjusting for time from symptom onset to treatment and nadir VA or VFMD. Radiologic biomarkers included length of optic nerve enhancement (> 25% vs. < 25%; > 50% vs. < 50%; and > 75% vs. < 75%); degree of orbital, canalicular, and intracranial or chiasmal optic nerve enhancement (mild vs. moderate to severe compared with the lacrimal gland); and absence versus presence of optic nerve sheath enhancement on baseline T1-weighted MRI.

RESULTS

A total of 129 eyes of 92 patients (median age, 37.0 years [interquartile range, 20.8-51.3 years]; 65.2% female) were included. Poor VA outcome was seen in 6.2% of patients, incomplete VA recovery was seen in 19.4% of patients, and poor VFMD outcome was seen in 16.9% of patients. Compared with eyes with moderate to severe enhancement, eyes with mild orbital optic nerve enhancement were more likely to have poor VA outcome (odds ratio [OR], 8.57; 95% confidence interval [CI], 1.85-51.14; P = 0.009), incomplete VA recovery (OR, 7.31, 95% CI, 2.42-25.47; P = 0.001), and poor VFMD outcome (adjusting for time to treatment: OR, 6.81; 95% CI, 1.85-28.98; P = 0.005; adjusting for nadir VFMD: OR, 11.65; 95% CI, 1.60-240.09; P = 0.04). Lack of optic nerve sheath enhancement additionally was associated with incomplete VA recovery (OR, 3.86; 95% CI, 1.19-12.85; P = 0.02) compared with the presence of enhancement. These associations remained consistent in subgroup logistic regression analysis of MRIs performed before initiation of treatment but were not seen in pairwise analysis of MRIs performed after treatment.

CONCLUSIONS

In eyes with first MOG-associated ON episodes, milder enhancement in the orbital optic nerve was associated with poorer VA and visual field recovery. Prospective and mechanistic studies are needed to confirm the prognostic usefulness of MRI in MOG-associated ON.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Peripheral immunity involvement in the cognitive impairment of sporadic amyotrophic lateral sclerosis

Background

Recent research has indicated the significance of immune activation in amyotrophic lateral sclerosis (ALS). However, the impact of peripheral immunity on cognitive impairment in sporadic ALS remains poorly characterized. Therefore, we aim to assess the relationship between peripheral immune parameters and cognitive impairment in patients with sporadic ALS.

Methods

A case-control study involving 289 patients with sporadic ALS was conducted. All participants underwent cognitive assessment and measurements of blood immune parameters. The main outcomes included adjusted odds ratios (ORs) in multivariate logistic regression analysis and adjusted coefficients in a multivariate linear regression model. Sensitivity analysis was performed with stratification by the King's clinical stage.

Results

Cognitive impairment was observed in 98 (33.9%) patients. Higher counts of leukocyte (OR, 0.53; 95% CI, 0.29 to 0.95; p = 0.03), neutrophil (OR, 0.48; 95% CI, 0.26 to 0.88; p = 0.02), and monocyte (OR, 0.33; 95% CI, 0.18 to 0.60; p < 0.001) were significantly associated with better cognitive preformence in sporadic ALS, particularly among patients in King's clinical stages 1 and 2. Conversely, a higher percentage of CD4+ T cells was linked to an increased risk of cognitive impairment (OR, 2.79; 95% CI, 1.52 to 5.09; p = 0.001), particularly evident in patients in King's clinical stage 3.

Conclusion

These results highlight the involvement of peripheral immunity in the cognitive impairment of sporadic ALS and suggest dynamic and intricate roles that vary across disease stages. Elucidating the links between immunity and ALS sheds light on the pathophysiological mechanisms underlying this fatal neurodegenerative disorder and informs potential immunotherapeutic strategies.

RNA-Seq Reveals Sex Differences in Gene Expression during Peripheral Neuropathic Inflammation and in Pain Relief from a COX-2 Inhibiting Theranostic Nanoemulsion

Given decades of neuroinflammatory pain research focused only on males, there is an urgent need to better understand neuroinflammatory pain in females. This, paired with the fact that currently there is no long-term effective treatment for neuropathic pain furthers the need to evaluate how neuropathic pain develops in both sexes and how it can be relieved. Here we show that chronic constriction injury of the sciatic nerve caused comparable levels of mechanical allodynia in both sexes. Using a COX-2 inhibiting theranostic nanoemulsion with increased drug loading, both sexes achieved similar reduction in mechanical hypersensitivity. Given that both sexes have improved pain behavior, we specifically explored differential gene expression between sexes in the dorsal root ganglia (DRG) during pain and relief. Total RNA from the DRG revealed a sexually dimorphic expression for injury and relief caused by COX-2 inhibition. Of note, both males and females experience increased expression of activating transcription factor 3 (Atf3), however, only the female DRG shows decreased expression following drug treatment. Alternatively, S100A8 and S100A9 expression appear to play a sex specific role in relief in males. The sex differences in RNA expression reveal that comparable behavior does not necessitate the same gene expression.

Immunity to the microbiota promotes sensory neuron regeneration

Tissue immunity and responses to injury depend on the coordinated action and communication among physiological systems. Here, we show that, upon injury, adaptive responses to the microbiota directly promote sensory neuron regeneration. At homeostasis, tissue-resident commensal-specific T cells colocalize with sensory nerve fibers within the dermis, express a transcriptional program associated with neuronal interaction and repair, and promote axon growth and local nerve regeneration following injury. Mechanistically, our data reveal that the cytokine interleukin-17A (IL-17A) released by commensal-specific Th17 cells upon injury directly signals to sensory neurons via IL-17 receptor A, the transcription of which is specifically upregulated in injured neurons. Collectively, our work reveals that in the context of tissue damage, preemptive immunity to the microbiota can rapidly bridge biological systems by directly promoting neuronal repair, while also identifying IL-17A as a major determinant of this fundamental process.

Stemness Activity Underlying Whole Brain Regeneration in a Basal Chordate

Understanding how neurons regenerate following injury remains a central challenge in regenerative medicine. Adult mammals have a very limited ability to regenerate new neurons in the central nervous system (CNS). In contrast, the basal chordate Polycarpa mytiligera can regenerate its entire CNS within seven days of complete removal. Transcriptome sequencing, cellular labeling, and proliferation in vivo essays revealed that CNS regeneration is mediated by a newly formed neural progeny and the activation of neurodevelopmental pathways that are associated with enhanced stem-cell activity. Analyzing the expression of 239 activated pathways enabled a quantitative understanding of gene-set enrichment patterns at key regeneration stages. The molecular and cellular mechanisms controlling the regenerative ability that this study reveals can be used to develop innovative approaches to enhancing neurogenesis in closely-related chordate species, including humans.

TRP channels: a journey towards a molecular understanding of pain

The perception of nociceptive signals, which are translated into pain, plays a fundamental role in the survival of organisms. Because pain is linked to a negative sensation, animals learn to avoid noxious signals. These signals are detected by receptors, which include some members of the transient receptor potential (TRP) family of ion channels that act as transducers of exogenous and endogenous noxious cues. These proteins have been in the focus of the field of physiology for several years, and much knowledge of how they regulate the function of the cell types and organs where they are expressed has been acquired. The last decade has been especially exciting because the 'resolution revolution' has allowed us to learn the molecular intimacies of TRP channels using cryogenic electron microscopy. These findings, in combination with functional studies, have provided insights into the role played by these channels in the generation and maintenance of pain.