A serial study of retinal changes following optic neuritis with sample size estimates for acute neuroprotection trials

The Study of Remyelinating Therapies in Multiple Sclerosis: Visual Outcomes as a Window Into Repair

INTRODUCTION

Amelioration of disability in multiple sclerosis requires the development of complementary therapies that target neurodegeneration and promote repair. Remyelination is a promising neuroprotective strategy that may protect axons from damage and subsequent neurodegeneration.

METHODS

A review of key literature plus additional targeted search of PubMed and Google Scholar was conducted.

RESULTS

There has been a rapid expansion of clinical trials studying putative remyelinating candidates, but further growth of the field is limited by the lack of consensus on key aspects of trial design. We have not yet defined the ideal study population, duration of therapy, or the appropriate outcome measures to detect remyelination in humans. The varied natural history of multiple sclerosis, coupled with the short time frame of phase II clinical trials, requires that we develop and validate biomarkers of remyelination that can serve as surrogate endpoints in clinical trials.

CONCLUSIONS

We propose that the visual system may be the most well-suited and validated model for the study potential remyelinating agents. In this review, we discuss the pathophysiology of demyelination and summarize the current clinical trial landscape of remyelinating agents. We present some of the challenges in the study of remyelinating agents and discuss current potential biomarkers of remyelination and repair, emphasizing both established and emerging visual outcome measures.

Disease Course of Clinically Isolated Optic Neuritis

BACKGROUND AND OBJECTIVES

Optic neuritis is the most common optic neuropathy in young adults and a frequent manifestation of multiple sclerosis. Its clinical course is pertinent to the design of visual pathway neuroprotection trials.

METHODS

This is a secondary analysis of longitudinal data from the TONE trial, which included 103 patients from 12 German academic tertiary centers with acute unilateral optic neuritis as a clinically isolated syndrome and baseline high-contrast visual acuity <0.5 decimal. Patients were randomized to 1,000 mg methylprednisolone i.v./d plus either erythropoietin (33,000 IU/d) or placebo (saline solution) for 3 days. They were followed up at standardized intervals with a battery of tests including high-contrast visual acuity, low-contrast letter acuity, contrast sensitivity, visual fields, visual evoked potentials, and retinal optical coherence tomography. At 6 months, participants answered a standardized questionnaire on vision-related quality of life (NEI-VFQ 25). We describe the disease course with mixed-effects piecewise linear models and calculate structure-function correlations using Pearson r. Because erythropoietin had no effect on the visual system, we use pooled (treatment-agnostic) data.

RESULTS

Patients experienced initial rapid and then decelerating improvements of visual function with thinning of inner and thickening of outer retinal layers. At 6 months, visual parameters were positively correlated with inner and negatively correlated with outer retinal thickness changes. Peripapillary retinal nerve fiber layer thinning predominantly occurred in sectors without previous swelling. At 6 months, macular ganglion cell and inner plexiform layer thinning was weakly correlated with the P100 peak time (r = -0.11) and moderately correlated with the amplitude of visual evoked potentials (r = 0.35). Only functional outcomes were at least moderately correlated with vision-related quality of life.

DISCUSSION

The longitudinal data from this large study cohort may serve as a reference for the clinical course of acute optic neuritis. The pattern of correlation between visual evoked potentials and inner retinal thinning may argue that the latter is mostly due to ganglion cell loss, rather than dysfunction. Visual pathway neuroprotection trials with functional outcomes are needed to confirm that candidate drugs will benefit patients' vision-related quality of life.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov, NCT01962571.

Sample size estimation for AQP4-IgG seropositive optic neuritis: Retinal damage detection by optical coherence tomography

We recruited four aquaporin-4 seropositive optic neuritis patients (five eyes) who received glucocorticoid treatment and underwent optical coherence tomography examination. Baseline medians of the macular ganglion cell layer plus inner plexiform layer (mGCIPL) thickness and volume for the eye of interest were 79.67 µm (73.664 ± 18.497 µm) and 0.58 mm3 (0.534 ± 0.134 mm3), respectively. At 2 months, the medians of the mGCIPL thickness and volume were 60.00 µm (51.576 ± 12.611 µm) and 0.44 mm3 (0.376 ± 0.091 mm3), respectively. At 6 months, the medians of the mGCIPL thickness and volume were 59.55 µm (46.288 ± 11.876 µm) and 0.44 mm3 (0.336 ± 0.084 mm3), respectively. Sample size estimate was achieved using two methods based on the mGCIPL thickness and volume data, with five effect sizes considered. The estimate based on the mGCIPL volume showed that 206 patients were needed at the 6-month follow-up; the power was 80% and effect size was 20%. In conclusion, this study detected retinal damage in aquaporin-4 seropositive optic neuritis patients by optical coherence tomography, and estimated the sample size for two-sample parallel designed clinical trials using two methods.

Prognostic factors of first-onset optic neuritis based on diagnostic criteria and antibody status: a multicentre analysis of 427 eyes

BACKGROUND

Optic neuritis (ON) prognosis is influenced by various factors including attack severity, underlying aetiologies, treatments and consequences of previous episodes. This study, conducted on a large cohort of first ON episodes, aimed to identify unique prognostic factors for each ON subtype, while excluding any potential influence from pre-existing sequelae.

METHODS

Patients experiencing their first ON episodes, with complete aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibody testing, and clinical data for applying multiple sclerosis (MS) diagnostic criteria, were enrolled. 427 eyes from 355 patients from 10 hospitals were categorised into four subgroups: neuromyelitis optica with AQP4 IgG (NMOSD-ON), MOG antibody-associated disease (MOGAD-ON), ON in MS (MS-ON) or idiopathic ON (ION). Prognostic factors linked to complete recovery (regaining 20/20 visual acuity (VA)) or moderate recovery (regaining 20/40 VA) were assessed through multivariable Cox regression analysis.

RESULTS

VA at nadir emerged as a robust prognostic factor for both complete and moderate recovery, spanning all ON subtypes. Early intravenous methylprednisolone (IVMP) was associated with enhanced complete recovery in NMOSD-ON and MOGAD-ON, but not in MS-ON or ION. Interestingly, in NMOSD-ON, even a slight IVMP delay in IVMP by >3 days had a significant negative impact, whereas a moderate delay up to 7-9 days was permissible in MOGAD-ON. Female sex predicted poor recovery in MOGAD-ON, while older age hindered moderate recovery in NMOSD-ON and ION.

CONCLUSION

This comprehensive multicentre analysis on first-onset ON unveils subtype-specific prognostic factors. These insights will assist tailored treatment strategies and patient counselling for ON.

Identifying Optical Coherence Tomography Markers for Multiple Sclerosis Diagnosis and Management

BACKGROUND

Multiple sclerosis (MS) is a common neurological disease affecting the optic nerve, directly or indirectly, through transsynaptic axonal degeneration along the visual pathway. New ophthalmological tools, arguably the most important being optical coherence tomography (OCT), could prove paramount in redefining MS diagnoses and shaping their follow-up protocols, even when the optic nerve is not involved.

METHODS

A prospective clinical study was conducted. In total, 158 eyes from patients previously diagnosed with relapsing remitting MS (RRMS)-with or without optic neuritis (ON), clinically isolated syndrome (CIS) with or without ON, and healthy controls were included. Each patient underwent an ophthalmologic exam and OCT evaluation for both eyes (a posterior pole analysis (PPA) and the optic nerve head radial circle protocol (ONH-RC)).

RESULTS

The macular retinal thickness (the 4 × 4, respectively, 2 × 2 grid) and thickness of the peripapillary retinal nerve fiber layer (pRNFL) were investigated. Various layers of the retina were also compared. Our study observed significant pRNFL thinning in the RRMS eyes compared to the control group, the pRNFL atrophy being more severe in the RRMS-ON eyes than the RRMS-NON eyes. In the ON group, the macular analysis showed statistically significant changes in the RRMS-ON eyes when compared only to the CIS-ON eyes, regarding decreases in the inner plexiform layer (IPL) thickness and inner nuclear layer (INL) on the central 2 × 2 macular grid. The neurodegenerative process affected both the inner retina and pRNFL, with clinical damage appearing for the latter in the following order: CIS-NON, CIS-ON, RRMS-NON, and RRMS-ON. In the presence of optic neuritis, SMRR patients presented an increase in their outer retina thickness compared to CIS patients.

CONCLUSIONS

To differentiate the MS patients from the CIS patients, in the absence of optic neuritis, OCT Posterior Pole Analysis could be a useful tool when using a central 2 × 2 sectors macular grid. Retinal changes in MS seem to start from the fovea and spread to the posterior pole. Finally, MS could lead to alterations in both the inner and outer retina, along with pRNFL.

Visually Evoked Potential as Prognostic Biomarker for Neuroaxonal Damage in Multiple Sclerosis From a Multicenter Longitudinal Cohort

BACKGROUND AND OBJECTIVES

With the increasing use of visually evoked potentials (VEPs) as quantitative outcome parameters for myelin in clinical trials, an in-depth understanding of longitudinal VEP latency changes and their prognostic potential for subsequent neuronal loss will be required. In this longitudinal multicenter study, we evaluated the association and prognostic potential of VEP latency for retinal neurodegeneration, measured by optical coherence tomography (OCT), in relapsing-remitting MS (RRMS).

METHODS

We included 293 eyes of 147 patients with RRMS (age [years, median ± SD] 36 ± 10, male sex 35%, F/U [years, median {IQR} 2.1 {1.5-3.9}]): 41 eyes had a history of optic neuritis (ON) ≥6 months before baseline (CHRONIC-ON), and 252 eyes had no history of ON (CHRONIC-NON). P100 latency (VEP), macular combined ganglion cell and inner plexiform layer volume (GCIPL), and peripapillary retinal nerve fiber layer thickness (pRNFL) (OCT) were quantified.

RESULTS

P100 latency change over the first year predicted subsequent GCIPL loss (36 months) across the entire chronic cohort (p = 0.001) and in (and driven by) the CHRONIC-NON subset (p = 0.019) but not in the CHRONIC-ON subset (p = 0.680). P100 latency and pRNFL were correlated at baseline (CHRONIC-NON p = 0.004, CHRONIC-ON p < 0.001), but change in P100 latency and pRNFL were not correlated. P100 latency did not differ longitudinally between protocols or centers.

DISCUSSION

VEP in non-ON eyes seems to be a promising marker of demyelination in RRMS and of potential prognostic value for subsequent retinal ganglion cell loss. This study also provides evidence that VEP may be a useful and reliable biomarker for multicenter studies.

Multiple sclerosis optic neuritis and trans-synaptic pathology on cortical thinning in people with multiple sclerosis

BACKGROUND

The multi-order visual system represents an excellent testing site regarding the process of trans-synaptic degeneration. The presence and extent of global versus trans-synaptic neurodegeneration in people with multiple sclerosis (pwMS) is not clear.

OBJECTIVE

To explore cross-sectional and longitudinal relationships between retinal, thalamic and cortical changes in pwMS with and without MS-related optic neuritis (pwMSON and pwoMSON) using MRI and optical coherence tomography (OCT).

METHODS

162 pwMS and 47 healthy controls (HCs) underwent OCT and brain MRI at baseline and 5.5-years follow-up. Peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell inner plexiform layer (mGCIPL) thicknesses were determined. Global volume measures of brain parenchymal volume (BPV)/percent brain volume change (PBVC), thalamic volume and T2-lesion volume (LV) were derived using standard analysis protocols. Regional cortical thickness was determined using FreeSurfer. Cross-sectional and longitudinal relationship between the retinal measures, thalamic volume and cortical thickness were assessed using age, BPV/PBVC and T2-LV adjusted correlations and regressions.

RESULTS

After age, BPV and T2-LV adjustment, the thalamic volume explained additional variance in the thickness of pericalcarine (R² increase of 0.066, standardized β = 0.299, p = 0.039) and lateral occipital (R2 increase of 0.024, standardized β = 0.299, p = 0.039) gyrii in pwMSON. In pwoMSON, the thalamic volume was a significant predictor only of control (frontal) regions of pars opercularis. There was no relationship between thalamic atrophy and cortical thinning over the follow-up in both pwMS with and without MSON. While numerically lower in the pwMSON group, the inter-eye difference was not able to predict the presence of MSON.

CONCLUSIONS

MSON can induce a measurable amount of trans-synaptic pathology on second-order cortical regions.

The role of SIRT1 level and SIRT1 gene polymorphisms in optic neuritis patients with multiple sclerosis

THE AIM

To investigate the role of Sirtuin 1 (SIRT1) level and SIRT1 (rs3818292, rs3758391, rs7895833) gene polymorphisms in patients with optic neuritis (ON) and multiple sclerosis (MS).

METHODS

79 patients with ON and 225 healthy subjects were included in the study. ON patients were divided into 2 subgroups: patients with MS (n = 30) and patients without MS (n = 43). 6 ON patients did not have sufficient data for MS diagnosis and were excluded from the subgroup analysis. DNA was extracted from peripheral blood leukocytes and genotyped by real-time polymerase chain reaction. Results were analysed using the program "IBM SPSS Statistics 27.0".

RESULTS

We discovered that SIRT1 rs3758391 was associated with a twofold increased odds of developing ON under the codominant (p = 0.007), dominant (p = 0.011), and over-dominant (p = 0.008) models. Also, it was associated with a threefold increased odds ofON with MS development under the dominant (p = 0.010), twofold increased odds under the over-dominant (p = 0.032) models and a 1.2-fold increased odds of ON with MS development (p = 0.015) under the additive model. We also discovered that the SIRT1 rs7895833 was significantly associated with a 2.5-fold increased odds of ON development under the codominant (p = 0.001), dominant (p = 0.006), and over-dominant (p < 0.001) models, and a fourfold increased odds of ON with MS development under the codominant (p < 0.001), dominant (p = 0.001), over-dominant (p < 0.001) models and with a twofold increased odds of ON with MS development (p = 0.013) under the additive genetic model. There was no association between SIRT1 levels and ON with/without MS development.

CONCLUSIONS

SIRT1 rs3758391 and rs7895833 polymorphisms are associated with ON and ON with MS development.

Optic Neuritis in Multiple Sclerosis—A Review of Molecular Mechanisms Involved in the Degenerative Process

Multiple sclerosis is a central nervous system inflammatory demyelinating disease with a wide range of clinical symptoms, ocular involvement being frequently marked by the presence of optic neuritis (ON). The emergence and progression of ON in multiple sclerosis is based on various pathophysiological mechanisms, disease progression being secondary to inflammation, demyelination, or axonal degeneration. Early identification of changes associated with axonal degeneration or further investigation of the molecular processes underlying remyelination are current concerns of researchers in the field in view of the associated therapeutic potential. This article aims to review and summarize the scientific literature related to the main molecular mechanisms involved in defining ON as well as to analyze existing data in the literature on remyelination strategies in ON and their impact on long-term prognosis.

Longitudinal retinal changes in MOGAD

OBJECTIVE

Patients with myelin oligodendrocyte glycoprotein antibody (MOG-IgG) associated disease (MOGAD) suffer from severe optic neuritis (ON) leading to retinal neuro-axonal loss, which can be quantified by optical coherence tomography (OCT). We assessed whether ON-independent retinal atrophy can be detected in MOGAD.

METHODS

Eighty MOGAD patients and 139 healthy controls (HC) were included. OCT data was acquired with 1) Spectralis spectral domain OCT (MOGAD (N=66) and HC (N=103)) and 2) Cirrus HD-OCT (MOGAD (N=14) and HC (N=36)). Macular combined ganglion cell and inner plexiform layer (GCIPL) and peripapillary retinal nerve fibre layer (pRNFL) were quantified.

RESULTS

At baseline, GCIPL and pRNFL were lower in MOGAD eyes with a history of ON (MOGAD-ON) compared with MOGAD eyes without a history of ON (MOGAD-NON) and HC (p<0.001). MOGAD-NON eyes had lower GCIPL volume compared to HC (p<0.001) in the Spectralis, but not in the Cirrus cohort. Longitudinally (follow-up up to 3 years), MOGAD-ON with ON within the last 6-12 months before baseline exhibited greater pRNFL thinning than MOGAD-ON with an ON >12 months ago (p<0.001). The overall MOGAD cohort did not exhibit faster GCIPL thinning compared with HC.

INTERPRETATION

Our study suggests the absence of attack-independent retinal damage in MOGAD. Yet, ongoing neuroaxonal damage or oedema resolution seems to occur for up to 12 months after ON, which is longer than what has been reported with other ON forms. These findings support that the pathomechanisms underlying optic nerve involvement and the evolution of OCT retinal changes after ON is distinct in MOGAD. This article is protected by copyright. All rights reserved.

A prospective longitudinal study on prognostic factors of visual recovery and structural change after a first episode of optic neuritis

BACKGROUND

To determine the role of OCT in predicting the final visual and structural outcome, and evaluate the correlation between functional eye outcome and retinal changes, in patients with first episode of optic neuritis (ON).

METHODS

In this prospective study, consecutive adult patients with acute ON underwent ophthalmological evaluation at baseline and 1 and 12 months, including OCT measurements of peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell and innerplexiform layer, and innernuclear layer thicknesses, high- and low-contrast visual acuity, visual field assessment, and baseline brain MRI. Univariate and multivariate linear regressions were used to assess predictive factors of outcome. Correlations between 12-month visual function and retinal structure were estimated by Spearman coefficients. Two groups of patients were analysed, with or without multiple sclerosis (MS).

RESULTS

Among 116 patients, 79 (68.1%) had MS, and 37 (31.9%) had ON not related to MS (including 19 idiopathic (i.e isolated) ON, and 13 and 5 with myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies, respectively). We found no independent predictive factor of visual and retinal outcome. Analysis of the relationship between the visual field test (mean deviation) and pRNFL thickness demonstrated a threshold of 75.4 μm and 66.4 μm, below which the mean deviation was worse, for patients with MS (p=0.007) and without MS (p<0.001), respectively.

CONCLUSIONS

We found that inner retinal layer measurements during the first month are not predictive of final outcome. The critical threshold of axonal integrity, below which visual function is damaged, is different between patients with and without MS.

Neuroprotective Effects of Novel Treatments on Acute Optic Neuritis—A Meta-Analysis

Optic neuritis, inflammation of the optic nerve, can cause visual impairment through retinal nerve fiber layer (RNFL) degeneration. Optical coherence tomography could serve as a sensitive noninvasive tool for measuring RNFL thickness and evaluating the neuroprotective effects of treatment. We conducted a meta-analysis to compare RNFL loss between novel add-on treatments and corticosteroid therapy at least 3 months after acute optic neuritis. The outcome measures were mean differences (MDs) in (1) RNFL thickness compared with the baseline in the affected and unaffected eye and (2) LogMAR visual acuity (VA). Seven studies involving five novel agents (memantine, erythropoietin, interferon-beta, phenytoin, and clemastine) were analyzed. When compared with the baseline RNFL thickness of the affected eye, the neuroprotective effects of novel add-on treatments could not be demonstrated. The difference in visual outcomes was also not significant between the two treatment groups. One study revealed that phenytoin has the potential to alleviate RNFL loss when the baseline thickness of the unaffected eye is considered. Larger randomized controlled trials with suitable outcome measures are warranted to evaluate the neuroprotective effects of novel treatments. Further studies should also tailor therapies to specific patient populations and investigate a more targeted treatment for acute optic neuritis.

Safety and efficacy of erythropoietin for the treatment of patients with optic neuritis (TONE): a randomised, double-blind, multicentre, placebo-controlled study

BACKGROUND

The human cytokine erythropoietin conveys neuroprotection in animal models but has shown ambiguous results in phase 2 clinical trials in patients with optic neuritis. We assessed the safety and efficacy of erythropoietin in patients with optic neuritis as a clinically isolated syndrome in a multicentre, prospective, randomised clinical trial.

METHODS

This randomised, placebo-controlled, double-blind phase 3 trial, conducted at 12 tertiary referral centres in Germany, included participants aged 18-50 years, within 10 days of onset of unilateral optic neuritis, with visual acuity of 0·5 or less, and without a previous diagnosis of multiple sclerosis. Participants were randomly assigned (1:1) to receive either 33 000 IU erythropoietin or placebo intravenously for 3 days as an adjunct to high-dose intravenous methylprednisolone (1000 mg per day). Block randomisation was performed by the trial statistician using an SAS code that generated randomly varying block sizes, stratified by study site and distributed using sealed envelopes. All trial participants and all study staff were masked to treatment assignment, except the trial pharmacist. The first primary outcome was atrophy of the peripapillary retinal nerve fibre layer (pRNFL), measured by optic coherence tomography (OCT) as the difference in pRNFL thickness between the affected eye at week 26 and the unaffected eye at baseline. The second primary outcome was low contrast letter acuity at week 26, measured as the 2·5% Sloan chart score of the affected eye. Analysis was performed in the full analysis set of all randomised participants for whom treatment was started and at least one follow-up OCT measurement was available. Safety was analysed in all patients who received at least one dose of the trial medication. This trial is registered at ClinicalTrials.gov, NCT01962571.

FINDINGS

108 participants were enrolled between Nov 25, 2014, and Oct 9, 2017, of whom 55 were assigned to erythropoietin and 53 to placebo. Five patients were excluded from the primary analysis due to not receiving the allocated medication, withdrawn consent, revised diagnosis, or loss to follow-up, yielding a full analysis set of 52 patients in the erythropoietin group and 51 in the placebo group. Mean pRNFL atrophy was 15·93 μm (SD 14·91) in the erythropoietin group and 14·65 μm (15·60) in the placebo group (adjusted mean treatment difference 1·02 μm; 95% CI -5·51 to 7·55; p=0·76). Mean low contrast letter acuity scores were 49·60 (21·31) in the erythropoietin group and 49·06 (21·93) in the placebo group (adjusted mean treatment difference -4·03; -13·06 to 5·01). Adverse events occurred in 43 (81%) participants in the erythropoietin group and in 42 (81%) in the placebo group. The most common adverse event was headache, occuring in 15 (28%) patients in the erythropoietin group and 13 (25%) patients in the placebo group. Serious adverse events occurred in eight (15%) participants in the erythropoietin and in four (8%) in the placebo group. One patient (2%) in the erythropoietin group developed a venous sinus thrombosis, which was treated with anticoagulants and resolved without sequelae.

INTERPRETATION

Erythropoietin as an adjunct to corticosteroids conveyed neither functional nor structural neuroprotection in the visual pathways after optic neuritis. Future research could focus on modified erythropoietin administration, assess its efficacy independent of corticosteroids, and investigate whether it affects the conversion of optic neuritis to multiple sclerosis.

FUNDING

German Federal Ministry of Education and Research (BMBF).

Optical coherence tomography monitoring and diagnosing retinal changes in multiple sclerosis

This study explores the use of optical coherence tomography (OCT) to monitor and diagnose multiple sclerosis (MS). The analysis of reduced total macular volume and peripapillary retinal nerve fiber layer thinning are shown. The severity of these defects increases as MS progresses, reflecting the progressive degeneration of nerve fibers and retinal ganglion cells. The OCT parameters are noninvasive, sensitive indicators that can be used to assess the progression of neurodegeneration and inflammation in MS.

Subclinical anterior optic pathway involvement in early multiple sclerosis and clinically isolated syndromes

Optical coherence tomography (OCT) is gaining increasing relevance in the assessment of patients with multiple sclerosis. Converging evidence point to the view that neuro-retinal changes, in eyes without acute optic neuritis, reflect inflammatory and neurodegenerative processes taking place throughout the CNS. The present study aims at exploring the usefulness of OCT as a marker of inflammation and disease burden in the earliest phases of the disease. Thus, a cohort of 150 consecutive patients underwent clinical, neurophysiological and brain MRI assessment as well as lumbar puncture as part of their diagnostic workup for a neurological episode suggestive of inflammatory CNS disorder; among those 32 patients had another previous misdiagnosed episode. For the present study, patients also received a visual pathway assessment (OCT, visual evoked potentials, visual acuity), measurement of CSF inflammatory markers (17 cytokines-chemokines, extracellular vesicles of myeloid origin), and dosage of plasma neurofilaments. Subclinical optic nerve involvement is frequently found in clinically isolated syndromes by visual evoked potentials (19.2%). OCT reveals ganglion cell layer asymmetries in 6.8% of patients; retinal fibre layer asymmetries, despite being more frequent (17.8%), display poor specificity. The presence of subclinical involvement is associated with a greater disease burden. Second, ganglion cell layer thinning reflects the severity of disease involvement even beyond the anterior optic pathway. In fact, the ganglion cell layer in eyes without evidence of subclinical optic involvement is correlated with Expanded Disability Status Scale, low contrast visual acuity, disease duration, brain lesion load, presence of gadolinium enhancing lesions, abnormalities along motor and somatosensory evoked potentials, and frequency of CSF-specific oligoclonal bands. Third, the inner nuclear layer thickens in a post-acute (1.1-3.7 months) phase after a relapse, and this phenomenon is counteracted by steroid treatment. Likewise, a longitudinal analysis on 65 patients shows that this swelling is transient and returns to normal values after 1 year follow-up. Notwithstanding, the clinical, MRI, serological and CSF markers of disease activity considered in the study are strictly associated with one another, but none of them are associated with the inner nuclear layer. Our findings challenge the current hypothesis that the inner nuclear layer is an acute phase marker of inflammatory activity. The present study suggests that instrumental evidence of subclinical optic nerve involvement is associated with a greater disease burden in clinically isolated syndrome. Neuro-retinal changes are present since the earliest phases of the disease and yield important information regarding the neurodegenerative and inflammatory processes occurring in the CNS.

Optical Coherence Tomography Reveals Longitudinal Changes in Retinal Damage Under Different Treatments for Neuromyelitis Optica Spectrum Disorder

Background: Progressive retinal neuroaxonal damage after acute optic neuritis may occur in neuromyelitis optica spectrum disorder (NMOSD). However, it is unclear if treatments used to prevent attacks influence neurodegeneration.

Objectives: We aimed to investigate retinal damage in patients treated with disease-modifying drugs in a longitudinal study.

Methods: We retrospectively included 50 patients with aquaporin 4-antibody-seropositive NMOSD. Peripapillary retinal nerve fiber layer (pRNFL) thickness, macular ganglion cell complex (mGCC) thickness, total macular volume (TMV), and optic disc measures were acquired by spectral domain optical coherence tomography in patients treated with tocilizumab, rituximab, and azathioprine.

Results: Longitudinally, in eyes with a history of ON (NMOSD^ON+), we observed annual thinning of mGCC [tocilizumab: −1.77 (−3.44, −0.09) μm, p = 0.041; rituximab: −2.03 (−3.58, −0.48) μm, p = 0.017; azathioprine: −1.79 (−2.22, −1.37) μm, p < 0.001], and pRNFL [tocilizumab: −2.07 (−0.75, −3.39) μm, p = 0.005; rituximab: −2.18 (−0.36, −4.00) μm, p = 0.023; azathioprine: −2.37 (−0.98, −3.75) μm, p = 0.003], reduced TMV [tocilizumab: −0.12 (−0.22, −0.01) mm³, p = 0.028; rituximab: −0.15 (−0.21, −0.08) mm³, p = 0.001; azathioprine: −0.12 (−0.20, −0.04) mm³, p = 0.006], and increased cup area [tocilizumab: 0.08 (−0.01, 0.16) mm², p = 0.010; rituximab: 0.07 (0.01, 0.12) mm², p = 0.019; azathioprine: 0.14 (0.02, 0.26) mm², p = 0.023]. However, we detected no significant differences in annual changes in mGCC, pRNFL, TMV, and cup area between patients with tocilizumab, rituximab, and azathioprine in NMOSD^ON+ eyes. NMOSD^ON− eyes did not display mGCC or pRNFL thinning in patients treated with tocilizumab and rituximab. Intriguingly, we observed significant thinning of mGCC in patients treated with azathioprine compared with tocilizumab [−0.84 (−1.50, −0.18) μm vs. −0.19 (−0.87, 0.48) μm, p = 0.012] and rituximab [−0.84 (−1.50, −0.18) μm vs. −0.07 (−1.25, −2.51) μm, p = 0.015] in NMOSD^ON− eyes.

Conclusions: This study demonstrated that retinal ganglion cell loss is independent of ON attacks in NMOSD. Tocilizumab and rituximab may delay mGCC thinning in NMOSD^ON− eyes compared with azathioprine.

Identification of posterior visual pathway lesions and MRI burden in people with Multiple Sclerosis

OBJECTIVES

This review systematically identifies posterior visual pathway lesions and MRI burden in people with multiple sclerosis (MS).

METHODS

The articles were searched through Web of Science, Medline, and Embase databases on January 2020, for English language articles from 2000 to 2019.

RESULTS

This review presents summary measures if related to MRI assessment to an overall measure of MS and visual pathway lesions. A total of 44 articles fulfilled all inclusion criteria, covering the period 2000-2019. Different atypical outcomes reveal a low risk for subsequent clinically predefined MS development, specifically in the presence of normal brain MRI. Several impairments related to quality of life have been identified as a result of the effect of retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer.

CONCLUSION

The afferent visual system in MS offers unique accessibility and structure-related functions with further understanding offered by electrophysiology, considering vision as a useful framework for examining new multiple sclerosis therapies.

Optical coherence tomography for detection of asymptomatic optic nerve lesions in clinically isolated syndrome

Objective

To evaluate the ability of intereye retinal thickness difference (IETD) measured by optical coherence tomography (OCT) to detect asymptomatic optic nerve involvement in clinically isolated syndrome (CIS).

Methods

We conducted a cross-sectional study of patients who recently presented a CIS (≤4.5 months). All patients underwent OCT and brain/optic nerve MRI. Optic nerve involvement was defined clinically (episode of optic neuritis [ON] or not) and radiologically (optic nerve hypersignal on 3D double inversion recovery [3D-DIR]). We evaluated the sensitivity and specificity of previously published IETD thresholds and report the observed optimal thresholds for identifying symptomatic optic nerve involvement but also for identifying asymptomatic optic nerve involvement (optic nerve hypersignal without ON history). Primary outcomes were ganglion cell–inner plexiform layer (GC-IPL) and peripapillary retinal nerve fiber layer IETD.

Results

The study group consisted of 130 patients. In the CIS with ON group, 3D-DIR showed a hypersignal in all 41 symptomatic optic nerves and in 11 asymptomatic optic nerves. In the CIS without ON group, 3D-DIR showed a unilateral optic nerve hypersignal in 22 patients and a bilateral optic nerve hypersignal in 7 patients. For the detection of symptomatic and asymptomatic optic nerve lesion, GC-IPL IETD had better performance. We found an optimal GC-IPL IETD threshold ≥2.83 µm (sensitivity 88.2, specificity 83.3%) for the detection of symptomatic lesions and an optimal GC-IPL IETD ≥1.42 µm (sensitivity 89.3%, specificity 72.6%) for the detection of asymptomatic lesions.

Conclusions

Detection of asymptomatic optic nerve lesions in CIS requires lower IETD thresholds than previously reported. GC-IPL IETD represents an alternative biomarker to MRI for the detection of asymptomatic optic nerve lesions.

Classification of evidence

This study provides Class I evidence that OCT accurately identifies asymptomatic optic nerve involvement in patients with CIS.

Effect of phenytoin on retinal ganglion cells in acute isolated optic neuritis

OBJECTIVE

Phenytoin has been shown to reduce the peripapillary retinal nerve fiber layer (pRNFL) loss in optic neuritis (ON). We evaluated the effects of phenytoin on retinal ganglion layers and visual outcomes of newly diagnosed acute ON.

METHODS

A randomized, placebo-controlled trial was conducted in a tertiary referral eye hospital and patients with the first episode of typical demyelinating ON, without any history of multiple sclerosis were randomly assigned to phenytoin or placebo. The thickness of ganglion cell-inner plexiform layer (GCIPL) measured by optical coherence tomography (OCT) was considered as the primary outcome.

RESULTS

One patient in the phenytoin group developed severe cutaneous rashes that progressed to Stevens-Johnson syndrome (SJS)/toxic epidermal necrosis (TEN), and further allocation of patients to the phenytoin group was stopped, and finally fifteen participants were included in the phenytoin group. Fifty-one patients were enrolled to the placebo group, from which four were excluded. Both visual acuity and field were not significantly different between the control and phenytoin groups after 1 and 6 months. Mean 3- and 6-mm macular GCIPL thicknesses decreased after 6 months to 73.6 ± 14.1 and 57.9 ± 7.5 μm, respectively, in the phenytoin group and to 71.6 ± 15.7 and 55.6 ± 6.6 μm, respectively, in the placebo group with no significant differences between the two groups (P = 0.77 and P = 0.26, respectively, linear multilevel model).

CONCLUSION

Phenytoin is not probably safe and effective as neuroprotection after acute ON. Further investigation with other sodium channel inhibitors could be considered.

Bilateral retinal pathology following a first-ever clinical episode of autoimmune optic neuritis

OBJECTIVE

This longitudinal study aimed to assess changes in retinal structure and visual function following a first-ever episode of acute optic neuritis (ON).

METHODS

Clinical and optical coherence tomography (OCT) data obtained over a period of 12 months were retrospectively analyzed in 41 patients with a first-ever clinical episode of acute ON. OCT scans, high-contrast visual acuity (HCVA), and low-contrast visual acuity (LCVA) were acquired at baseline and at 1, 3, 6, and 12 months thereafter. Macular ganglion cell and inner plexiform layer (GCIP), peripapillary retinal nerve fiber layer (pRNFL), and macular inner nuclear layer (INL) thicknesses were assessed by OCT. Linear mixed-effects models were used to analyze OCT variables of ipsilateral ON and contralateral non-ON (NON) eyes over time.

RESULTS

The mean change of GCIP thickness in ON eyes was significant at all follow-up time points, with nearly 75% of the total reduction having occurred by month 1. In ON eyes, thinner GCIP thickness at month 1 correlated with lower LCVA at month 3. Mean pRNFL thickness in ON eyes differed significantly from NON eyes at all postbaseline time points. INL thickness was significantly increased in ON eyes (month 1) but also in contralateral NON eyes (month 12).

CONCLUSIONS

Retinal structural damage develops rapidly following acute ON and is associated with subsequent functional visual deficits. Our results also suggest bilateral retinal pathology following unilateral ON, possibly caused by subclinical involvement of the contralateral NON eyes. Moreover, our data may assist in clinical trial planning in studies targeting tissue damage in acute ON.

Retinal Degeneration After First-Ever Optic Neuritis Helps Differentiate Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder

Objective: Differentiation between neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) in the early phase is challenging but crucial for treatment and prognosis.

Methods: We performed a prospective cross-sectional study to discriminate NMOSD from MS by evaluating retinal degeneration in optical coherence tomography (OCT) after a first-ever optic neuritis (ON) episode. Seventy-three NMOSD patients and 38 MS patients with ON at least 3 months prior were assessed by OCT, best-corrected visual acuity (VA), and 2.5% low-contrast VA. Multivariate linear regression models were used for comparisons. Receiver operating characteristic curves and Youden index were used for determining the discriminative value of retinal nerve fiber layer thickness (RNFL) and VA in distinguishing NMOSD from MS.

Results: Among eyes with retinal degeneration after a first-ever ON episode (n = 93), NMOSD eyes (n = 60) presented thinner RNFL (p < 0.001) and worsened VA (p < 0.001) relative to MS eyes (n = 33). Furthermore, a RNFL thinner than 78.9 μm had a specificity of 93.9% for NMOSD; combined with a VA of <0.4 decimal, these characteristics provided 100% specificity for NMOSD.

Conclusions: The first-ever ON eyes showed more severe retina degeneration in patients with NMOSD than MS, which could establish a cut-off of RNFL thickness and VA to distinguish NMOSD from MS in the early phase.

Early auto-immune targeting of photoreceptor ribbon synapses in mouse models of multiple sclerosis

Optic neuritis is one of the first manifestations of multiple sclerosis. Its pathogenesis is incompletely understood, but considered to be initiated by an auto‐immune response directed against myelin sheaths of the optic nerve. Here, we demonstrate in two frequently used and well‐validated mouse models of optic neuritis that ribbon synapses in the myelin‐free retina are targeted by an auto‐reactive immune system even before alterations in the optic nerve have developed. The auto‐immune response is directed against two adhesion proteins (CASPR1/CNTN1) that are present both in the paranodal region of myelinated nerves as well as at retinal ribbon synapses. This occurs in parallel with altered synaptic vesicle cycling in retinal ribbon synapses and altered visual behavior before the onset of optic nerve demyelination. These findings indicate that early synaptic dysfunctions in the retina contribute to the pathology of optic neuritis in multiple sclerosis.

Incorporating non-linear alignment and multi-compartmental modeling for improved human optic nerve diffusion imaging

In vivo human optic nerve diffusion magnetic resonance imaging (dMRI) is technically challenging with two outstanding issues not yet well addressed: (i) non-linear optic nerve movement, independent of head motion, and (ii) effect from partial-volumed cerebrospinal fluid or interstitial fluid such as in edema. In this work, we developed a non-linear optic nerve registration algorithm for improved volume alignment in axial high resolution optic nerve dMRI. During eyes-closed dMRI data acquisition, optic nerve dMRI measurements by diffusion tensor imaging (DTI) with and without free water elimination (FWE), and by diffusion basis spectrum imaging (DBSI), as well as optic nerve motion, were characterized in healthy adults at various locations along the posterior-to-anterior dimension. Optic nerve DTI results showed consistent trends in microstructural parametric measurements along the posterior-to-anterior direction of the entire intraorbital optic nerve, while the anterior portion of the intraorbital optic nerve exhibited the largest spatial displacement. Multi-compartmental dMRI modeling, such as DTI with FWE or DBSI, was less subject to spatially dependent biases in diffusivity and anisotropy measurements in the optic nerve which corresponded to similar spatial distributions of the estimated fraction of isotropic diffusion components. DBSI results derived from our clinically feasible (∼10 min) optic nerve dMRI protocol in this study are consistent with those from small animal studies, which provides the basis for evaluating the utility of multi-compartmental dMRI modeling in characterizing coexisting pathophysiology in human optic neuropathies.

Longitudinal optical coherence tomography study of optic atrophy in secondary progressive multiple sclerosis: Results from a clinical trial cohort

BACKGROUND

Limited prospective information exists regarding spectral-domain optical coherence tomography (SD-OCT) in secondary progressive multiple sclerosis (SPMS).

OBJECTIVE

Document cross-sectional and longitudinal retinal nerve fiber layer (RNFL) and macular ganglion cell plus inner plexiform layer (GCIPL) features of an SPMS clinical trial cohort.

METHODS

Prospective, observational study using a 2-year randomized placebo-controlled SPMS trial cohort with yearly SD-OCT testing. Post hoc analysis determined influences of optic neuritis (ON), disease duration, and baseline SD-OCT on annualized atrophy rates and on correlations between OCT and brain atrophy.

RESULTS

Mean RNFL and GCIPL values of patients ( n = 47, mean age = 59 years, mean disease duration = 30 years) were significantly lower among eyes with prior ON than those without (no history of ON (NON)). Annualized RNFL (-0.31 µm/year) and GCIPL (-0.29 µm/year) atrophy rates did not differ between ON and NON eyes. Baseline RNFL thickness >75 µm was associated with greater annualized RNFL atrophy (-0.85 µm/year). Neither RNFL nor GCIPL atrophy correlated with whole-brain atrophy.

CONCLUSION

This study suggests that eyes with and without ON history may be pooled for atrophy analysis in SPMS clinical trials using SD-OCT. Low baseline RNFL, small retinal atrophy rates, and lack of correlation with whole-brain atrophy in this population are important trial design considerations.

Novel uses of retinal imaging with optical coherence tomography in multiple sclerosis

Introduction: Multiple Sclerosis (MS) is the most common chronic autoimmune neuroinflammatory condition in young adults. It is often accompanied by optic neuritis (ON) and retinal neuro-axonal damage causing visual disturbances. Optical coherence tomography (OCT) is a sensitive non-invasive method for quantifying intraretinal layer volumes. Recently, OCT not only showed to be a reliable marker for ON-associated damage, but also proved its high prognostic value for functional outcome and disability accrual in patients with MS. Consequently, OCT is discussed as a potential marker for monitoring disease severity and therapeutic response in individual patients. Areas covered: This article summarizes our current understanding of structural retinal changes in MS and describes the future potential of OCT for differential diagnosis, monitoring of the disease course and for clinical trials. Expert commentary: Today, OCT is used in clinical practice in specialized MS centers. Standardized parameters across devices are urgently needed for supporting clinical utility. Novel parameters are desirable to increase sensitivity and specificity in terms of MS.

Optical coherence tomography in acute optic neuritis: A population-based study

OBJECTIVES

To measure early structural damage caused by autoimmune inflammatory optic neuritis (ON) by optical coherence tomography (OCT) in a population-based cohort.

METHODS

In a prospective population-based study over 24 months in Southern Denmark, patients diagnosed with acute ON and without prior diagnosis of a chronic neuroinflammatory disorder were included and examined with OCT, visual evoked potentials (VEP), visual fields, high contrast visual acuity (HCVA), and low contrast letter acuity (LCLA). Structural and functional outcomes were determined at 6-month follow-up based on interocular differences.

RESULTS

The 50 included patients had on average 16.9 μm peripapillary retinal nerve fiber layer loss, 10.6 μm ganglion cell and inner plexiform layer (GCIP) loss, and an average HCVA decrease of 0.22 dec. Based on a linear regression model, average GCIP loss amounted to -0.2 μm per day and started 8 days after onset. OCT outcomes but not VEP correlated well with all visual function measurements at follow-up. Structural and functional damage in 20 patients (40%) diagnosed de novo with multiple sclerosis (MS) and in 2 patients (4%) with positive myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) test did not differ from patients with idiopathic ON.

CONCLUSIONS

Optic neuritis causes substantial retinal damage and vision loss independent of the underlying disease. Our study supports that GCIP damage starts closely to clinical onset. Good structure-function correlations between OCT and vision support the importance of OCT in monitoring acute ON.

Time to steroid treatment in severe acute optic neuritis

OBJECTIVES

Steroid treatment can accelerate visual recovery in patients with optic neuritis (ON), but it is unknown whether the timing of the start of treatment influences the outcome. The main purpose of this observational study was to assess the effect of early onset steroid treatment of ON on visual prognosis and retinal morphology.

METHODS

Forty-nine patients with acute mild/moderate (n = 21) or severe (n = 28) ON, and an equal number of healthy controls were enrolled. Patients with severe ON either received early onset steroid treatment (initiated within 1 week of presentation with visual loss) (n = 9), late-onset treatment (initiated after 1 week) (n = 13), or no treatment (n = 6). Visual function and retinal morphology was studied after 6 and 12 months.

RESULTS

All measures of visual function had improved after 6 months (p ≤ 0.03) in the three groups with severe ON. This was not the case for Rayleigh match setting range (SR) in the nontreated group (p = 0.24), or for SR (p = 0.08) and latency to P100 of visual evoked potential (p = 0.08) in the late-onset treated group. After 12 months, further improvement occurred in the nontreated and late-treated groups, but not in the early treated group. Macular retinal nerve fiber layer (mRNFL) and ganglion cell plus inner plexiform layer had decreased significantly (p ≤ 0.001) in all three groups with severe ON after 6 months. After 12 months, only mRNFL had further significantly decreased and only in the late-onset treated group (p = 0.02).

CONCLUSION

The beneficial effects of early onset steroid treatment of ON is limited to a few months whereas the long-term prognosis is independent of the timing of treatment.

Altered Macular Microvasculature in Neuromyelitis Optica Spectrum Disorders

PURPOSE

To evaluate macular microvascular changes in neuromyelitis optica spectrum disorders (NMOSD) by using optical coherence tomography angiography (OCT-A) and investigate their correlations with neuroaxonal structural damage evaluated with spectral-domain OCT (SD-OCT).

DESIGN

Cross-sectional study.

METHODS

Twenty eyes of 20 patients with NMOSD and 21 eyes from 21 healthy controls were enrolled. OCT-A was used to obtain microvascular network images of the whole, superficial, and deep retinal capillary plexuses (WRCP, SRCP, and DRCP) in a 3-mm-diameter area around the macula. SD-OCT was used to obtain the intraretinal thickness. Custom automated algorithms quantified the thickness of the intraretinal layers as well as microvascular density of the retinal capillary layers.

RESULTS

NMOSD patients showed significantly decreased microvascular density in both SRCP and DRCP (P < .05) compared to controls. The decreased microvascular density in SRCP and DRCP significantly correlated with the frequency of optic neuritis attack (P < .05). Both SRCP and DRCP microvascular density significantly correlated (P < .05) with retinal nerve fiber layer and ganglion cell layer with inner plexiform layer. SRCP microvascular density moderately correlated with visual acuity, while a stronger correlation was found between DRCP and visual acuity.

CONCLUSIONS

Decreased microvascular density in NMOSD patients correlated with the worsening of their visual acuity. Correlation between microvascular impairment and neuroaxonal thinning revealed that retinal microvascular alteration may contribute to neuroaxonal loss in NMOSD patients. OCT-A with measurable analysis offers a new path of study and will likely be useful as an objective biomarker for detecting microvascular impairment in NMOSD.

Frequent retinal ganglion cell damage after acute optic neuritis

BACKGROUND

To identify the extent of ganglion cell damage after first-time optic neuritis (ON) using the inter-ocular difference between affected and fellow eyes, and whether this approach is able to detect more patients suffering from ganglion cell damage than using absolute values.

METHODS

Thirty-four patients with first-time unilateral ON were followed for a median 413 days. Patients underwent optical coherence tomography testing to determine ganglion cell plus inner plexiform layer thickness (GCIP). Ganglion cell loss was quantified as GCIP difference between ON-affected and fellow eyes (inter-GCIP) and was compared against measurements from 93 healthy controls (HC). Visual function was assessed with high contrast visual acuity; and standard automated perimetry-derived measures of mean deviation and foveal threshold.

RESULTS

At clinical presentation after median 19 days from symptom onset, 47.1% of patients showed early GCIP thinning in the ON-affected eye based on inter-GCIP. At the last visit acute ON was associated with 16.1 ± 10.0 µm GCIP thinning compared to fellow eyes (p = 3.669e-06). Based on inter-GCIP, 84.9% of ON patients sustained GCIP thinning in their affected eye at the last visit, whereas using absolute values only 71.0% of patients suffered from GCIP thinning (p = 0.002076). Only 32.3% of these patients had abnormal visual function. The best predictor of GCIP thinning as a measure of ON severity at the last visit was worse visual field mean deviation at clinical presentation.

CONCLUSION

Inter-ocular GCIP identifies significantly more eyes suffering damage from ON than absolute GCIP, visual fields or visual acuity loss. Effective interventional options are needed to prevent ganglion cell loss.

Optic neuritis as a phase 2 paradigm for neuroprotection therapies of multiple sclerosis: update on current trials and perspectives

PURPOSE OF REVIEW

In multiple sclerosis as the most common inflammatory demyelinating disease in Western countries, major therapeutic success has been achieved with regard to strategies targeting immunological master switches. These approaches effectively reduce inflammatory disease activity but fail to address ongoing neurodegeneration or disturbed regeneration. However, intense research efforts investigating molecular mechanisms of disease have identified 'druggable' targets for prevention of inflammatory neurodegeneration and disturbed regeneration. This review covers recent developments in clinical trials using optic neuritis as a model for screening such neuroprotective and neuroregenerative therapeutic approaches.

RECENT FINDINGS

Optic neuritis has been used in a series of recent pilot studies investigating the effects of erythropoietin, simvastatin, autologous mesenchymal stem cells, phenytoin, as well as blockade of LINGO-1 (opicinumab). Of note, these studies applied novel outcome measures related to function and structure of the visual pathway, including optical coherence tomography, full-field visual-evoked potentials, multifocal visual-evoked potential, high as well as low-contrast visual acuity. Comparison of these different approaches reveals novel insights into short-term evolution of neurobiological effects during optic neuritis and the window of opportunity for therapeutic interventions.

SUMMARY

Translation of neuroprotective and neuroregenerative approaches to clinical reality represents a huge challenge. Optic neuritis as a prototypic autoimmune demyelinating disease offers an option for testing new therapies targeting key deleterious processes in multiple sclerosis.

Do eyes with and without optic neuritis in multiple sclerosis age equally?

PURPOSE

Anterior visual pathway reflects axonal loss caused by both optic neuritis (ON) and neurodegeneration in multiple sclerosis (MS). Although the axonal injury post-ON is thought to be complete by 6 months of onset, most studies using optical coherence tomography (OCT) to evaluate retinal changes as a marker of neurodegeneration exclude eyes with a history of ON or consider them separately. The objective of this study was to assess whether the eyes post-ON (>6 months) show in later years different rate of chronic retinal changes than the fellow eyes not affected by ON.

PATIENTS AND METHODS

Fifty-six patients with MS with a history of ON in one eye (ON eyes) and no ON in the fellow (FL) eye, who were followed by OCT for >2 years, were selected from a cohort of patients with MS. Paired eye analysis was performed.

RESULTS

Mean interval post-ON at baseline was 5.65 (SD 5.05) years. Mean length of follow-up by OCT was 4.57 years. There was no statistical difference in absolute or relative thinning of retinal nerve fiber layer in peripapillary area between the ON and FL eyes.

CONCLUSION

This study has shown that we do not need to exclude eyes with a history of ON from longitudinal studies of neurodegeneration in MS, provided that we use data outside of the frame of acute changes post-ON. Long-term changes of peripapillary retinal nerve fiber layer in ON and FL eyes are equal.

[Immunomodulation and neuroprotection in optic neuritis]

BACKGROUND

To date, high-dose corticosteroids constitute the only established treatment of acute optic neuritis (ON); however, steroids cannot prevent the loss of retinal nerve fibers. New acute therapeutic drugs are therefore being sought for a reduction of ganglion cell death.

METHODS

Literature search comprising clinical studies on treatment of ON with immunomodulatory and neuroprotective drugs.

RESULTS

For the immunomodulatory drug simvastatin some evidence for long-term benefits was shown, particularly regarding visual evoked potentials. For the neuroprotective substance memantine a potential positive effect on retinal nerve fiber layer (RNFL) thickness was revealed. Likewise in one publication a reduction in loss of RNFL thickness could be demonstrated for erythropoietin and this drug is currently being extensively investigated in a phase III randomized controlled trial (RCT). The results of studies with phenytoin, amiloride and anti-leucine-rich repeat and immunoglobulin domain containing 1 protein (anti-LINGO-1) antibodies are awaiting publication.

CONCLUSION

According to the data from recent treatment trials, there is hope that neuronal loss in ON can be reduced with the help of immunomodulatory substances, such as simvastatin or neuroprotective agents, such as memantine and erythropoietin.

Sirtuins Expression and Their Role in Retinal Diseases

Sirtuins have received considerable attention since the discovery that silent information regulator 2 (Sir2) extends the lifespan of yeast. Sir2, a nicotinamide adenine dinucleotide- (NAD-) dependent histone deacetylase, serves as both a transcriptional effector and energy sensor. Oxidative stress and apoptosis are implicated in the pathogenesis of neurodegenerative eye diseases. Sirtuins confer protection against oxidative stress and retinal degeneration. In mammals, the sirtuin (SIRT) family consists of seven proteins (SIRT1–SIRT7). These vary in tissue specificity, subcellular localization, and enzymatic activity and targets. In this review, we present the current knowledge of the sirtuin family and discuss their structure, cellular location, and biological function with a primary focus on their role in different neuroophthalmic diseases including glaucoma, optic neuritis, and age-related macular degeneration. The potential role of certain therapeutic targets is also described.

Outcome Measures in Clinical Trials for Multiple Sclerosis

Due to the heterogeneous nature of the disease, it is a challenge to capture disease activity of multiple sclerosis (MS) in a reliable and valid way. Therefore, it can be difficult to assess the true efficacy of interventions in clinical trials. In phase III trials in MS, the traditionally used primary clinical outcome measures are the Expanded Disability Status Scale and the relapse rate. Secondary outcome measures in these trials are the number or volume of T2 hyperintense lesions and gadolinium-enhancing T1 lesions on magnetic resonance imaging (MRI) of the brain. These secondary outcome measures are often primary outcome measures in phase II trials in MS. Despite several limitations, the traditional clinical measures are still the mainstay for assessing treatment efficacy. Newer and potentially valuable outcome measures increasingly used or explored in MS trials are, clinically, the MS Functional Composite and patient-reported outcome measures, and on MRI, brain atrophy and the formation of persisting black holes. Several limitations of these measures have been addressed and further improvements will probably be proposed. Major improvements are the coverage of additional functional domains such as cognitive functioning and assessment of the ability to carry out activities of daily living. The development of multidimensional measures is promising because these measures have the potential to cover the full extent of MS activity and progression. In this review, we provide an overview of the historical background and recent developments of outcome measures in MS trials. We discuss the advantages and limitations of various measures, including newer assessments such as optical coherence tomography, biomarkers in body fluids and the concept of 'no evidence of disease activity'.

Retinal ganglion cell and axonal loss in optic neuritis: risk factors and visual functions

PurposeThe peripapillary retinal nerve fiber layer (pRNFL) and the macular ganglion cell-inner plexiform layer (GCIPL) are important predictive factors for the prognosis of optic neuritis (ON). We investigated the risk factors for pRNFL and GCIPL thinning in ON and its relationship with visual function.Patients and methodsWe analyzed 33 eyes of 33 patients with a first attack of unilateral ON. Patients were divided into two groups according to pRNFL and GCIPL thinning, using spectral-domain optical coherence tomography. We evaluated patients' age, sex, color vision, visual acuity (VA), optic nerve findings on MRI, elapsed period from onset of visual symptoms to steroid treatment, visual field (VF) mean deviation (MD), average pRNFL thickness, and GCIPL thickness.ResultsThere was no patient with residual VF defect in the groups without pRNFL or GCIPL thinning. Significant correlations were found between pRNFL (some sectors) and GCIPL (all sectors) thickness and BCVA and VF MD (P<0.03 for all). Multivariate logistic regression analysis revealed that only worse initial VF MD was a significant risk factor of pRFNL and GCIPL thinning after ON (OR, 0.841; 95% CI, 0.730-0.970; P=0.017 and OR, 0.871; 95% CI, 0.761-0.998; P=0.046, respectively).ConclusionRetinal ganglion cell and axonal losses occurred in ON cases showing severe initial VF loss. Therefore, it is necessary to pay more attention to the degree of initial VF loss in ON while considering the possibility of residual VF loss accompanying pRNFL and GCIPL thinning.

Disease Activity and Conversion into Multiple Sclerosis after Optic Neuritis Is Treated with Erythropoietin

Changes in cerebral lesion load by magnetic resonance imaging (MRI) in patients from a double-blind, placebo-controlled, phase II study on erythropoietin in clinically isolated optic neuritis (ClinicalTrials.gov, NCT00355095) were analyzed. Therefore, patients with acute optic neuritis were assigned to receive either 33,000 IU of recombinant human erythropoietin (IV) daily for three days, or a placebo, as an add-on to methylprednisolone. Of 35 patients, we investigated changes in cerebral lesion load in MRIs obtained at baseline and at weeks 4, 8, and 16. In 5 of the 35 patients, we found conversion into multiple sclerosis (MS) based on MRI progression only. These five patients had received the placebo. Another five patients showed MRI progression together with relapses. Three of these patients had received erythropoietin, and two the placebo. Yet, analyzing the change in absolute numbers of periventricular, juxtacortical, and infratentorial lesions including gadolinium-enhancing lesions, there were no significant differences between the groups. Although effective in terms of retinal nerve fiber layer protection, erythropoietin treatment of acute isolated optic neuritis did not influence further evolution of MRI lesions in the brain when comparing absolute numbers. However, early conversion from clinically isolated syndrome to MS assessed by MRI activity seemed to occur more frequently in the placebo-treated group.

Modeling the Chronic Loss of Optic Nerve Axons and the Effects on the Retinal Nerve Fiber Layer Structure in Primary Disorder of Myelin

Purpose

We determined whether the chronic lack of optic nerve myelination and subsequent axon loss is associated with optical coherence tomography (OCT) changes in the retinal nerve fiber layer (RNFL), and whether this models what occurs in multiple sclerosis (MS) and confers its use as a surrogate marker for axon degeneration.

Methods

Using an animal model of Pelizaeus-Merzbacher disease (shp) bilateral longitudinal measurements of the peripapillary RNFL (spectral-domain OCT), electroretinograms (ERG), and visual evoked potentials (VEP) were performed in affected and control animals from 5 months to 2 years and in individual animals at single time points. Light and electron microscopy of the optic nerve and retina and histomorphometric measurements of the RNFL were compared to OCT data.

Results

Of the shp animals, 17% had an average reduction of OCT RNFL thickness on the superior retinal quadrant compared to controls (P < 0.05). Electroretinograms showed normal photopic A- and B-waves but flash VEPs were disorganized in shp animals. Morphologically, the shp retinas and optic nerves revealed significant RNFL thinning (P < 0.001) without retinal ganglion cell (RGC) loss, decrease total and relative retinal axonal area, and loss of optic nerve axons. There was strong positive correlation between OCT and morphometric RNFL thickness measurements (r = 0.878, P = 0.004).

Conclusion

The loss of optic nerve axons demonstrated in the shp model resulted in moderate thinning of the RNFL confirmed by OCT and histology. These results indicate that OCT-derived RNFL measurement can be a useful surrogate biomarker of optic nerve axon loss and potentially disease progression in demyelinating diseases.

Impact of Autologous Mesenchymal Stem Cell Infusion on Neuromyelitis Optica Spectrum Disorder: A Pilot, 2-Year Observational Study

AIMS

We evaluate safety and efficacy of autologous bone marrow-derived mesenchymal stem cells (MSCs) as a potential treatment for neuromyelitis optica spectrum disorder (NMOSD).

METHODS

Fifteen patients with NMOSD were recruited. All patients received a single intravenous infusion of 1.0 × 10(8) autologous MSC within 3-4 generations derived from bone marrow. The primary endpoints of the study were efficacy as reflected by reduction in annualized relapse rates (ARRs) and inflammatory lesions observed by MRI.

RESULTS

At 12 months after MSC infusion, the mean ARR was reduced (1.1 vs. 0.3, P = 0.002), and the T2 or gadolinium-enhancing T1 lesions decreased in the optic nerve and spinal cord. Disability in these patients was reduced (EDSS, 4.3 vs. 4.9, P = 0.021; visual acuity, 0.4 vs. 0.5, P = 0.007). The patients had an increase in retinal nerve fiber layer thickness, optic nerve diameters and upper cervical cord area. We did not identify any serious MSC-related adverse events. At 24 months of MSC infusion, of 15 patients, 13 patients (87%) remained relapse-free, the mean ARR decreased to 0.1; the disability of 6 patients (40%) was improved, and the mean EDSS decreased to 4.0.

CONCLUSIONS

This pilot trial demonstrates that MSC infusion is safe, reduces the relapse frequency, and mitigates neurological disability with neural structures in the optic nerve and spinal cord recover in patients with NMOSD. The beneficial effect of MSC infusion on NMOSD was maintained, at least to some degree, throughout a 2-year observational period.

A prospective cohort study of vitamin D in optic neuritis recovery

Background:

Vitamin D sufficiency is associated with better inflammatory outcomes in multiple sclerosis (MS). We hypothesize that it is also associated with better long-term neurodegenerative measures.

Objectives:

To show that vitamin D sufficient patients (25-hydroxy vitamin D (25(OH)D) > 80 nmol/L) have better optical coherence tomography (OCT) neuroaxonal measures of ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL) thickness after optic neuritis.

Methods:

In this prospective cohort study, acute optic neuritis patients underwent OCT and serum 25(OH)D assessments at baseline and at month 6, with comparisons between vitamin D sufficient and insufficient patients, and men and women. Potential confounding variables were evaluated.

Results:

Of 49 enrolled, 36 had complete, analyzable data. At baseline, vitamin D insufficiency was associated with greater RNFL thickness (134.3 vs. 95.2 µm; p = 0.003) in affected eyes. At month 6, insufficient patients had greater GCL thinning (GCL inter-eye difference: 14.2 vs. 4.0 µm, p = 0.008). Men had greater RNFL and GCL thinning than women (GCL: 61.2 vs. 69.6 µm, p = 0.036).

Conclusion:

Acutely, in optic neuritis, RNFL thickness is increased with vitamin D insufficiency. Chronically, neuronal, and possibly axonal loss are associated with vitamin D insufficiency and male gender, suggesting vitamin D and female gender may confer neuroprotection in optic neuritis, and possibly, central nervous system (CNS) inflammatory disease.

Adding Papillomacular Bundle Measurements to Standard Optical Coherence Tomography Does Not Increase Sensitivity to Detect Prior Optic Neuritis in Patients with Multiple Sclerosis

Purpose

To improve the detection of retinal nerve fiber layer (RNFL) thinning in multiple sclerosis (MS), a special peripapillary ring scanning algorithm (N-site RNFL, N-RNFL) was developed for spectral domain optical coherence tomography (SD-OCT). In contrast to the standard protocol (ST-RNFL) scanning starts nasally, not temporally, and provides an additional sector of analysis, the papillomacular bundle (PMB). We aimed to ascertain whether the temporal RNFL differs between the two techniques, whether N-RNFL is more sensitive than ST-RNFL to detect previous optic neuritis (ON), and whether analyzing the PMB adds additional sensitivity. Furthermore, we investigated whether RNFL is associated with disease severity and/or disease duration.

Methods

We conducted a cross-sectional case-control study of 38 patients with MS, of whom 24 had a history of ON, and 40 healthy controls (HC). Subjects with ON within the previous 6 months were excluded. Records included clinical characteristics, visual evoked potentials (VEP), and SD-OCT in both techniques.

Results

In a total of 73 evaluable MS eyes, temporal N-RNFL was abnormal in 17.8%, temporal ST-RNFL in 19.2%, and the PMB-RNFL in 21.9%. In ON eyes, the sensitivity of temporal N-RNFL and ST-RNFL did not differ significantly (37.0%/33.3%, p = 0.556). The sensitivity of VEP was 85.2%. RNFL thickness was associated with disease severity in all eyes, with and without a history of ON, and with disease duration.

Conclusion

The two OCT techniques detected previous ON with similar sensitivity, but the sensitivity of VEPs was superior to that of both N-RNFL and ST-RNFL. Our results indicate that the widely used ST-RNFL technique is appropriate for peripapillary RNFL measurements in MS patients.

Retinal ganglion cell layer thinning within one month of presentation for optic neuritis

BACKGROUND

Spectral domain optical coherence tomography (SD-OCT) reveals retinal ganglion cell layer plus inner plexiform layer (GCL+IPL) and peripapillary retinal nerve fiber layer (pRNFL) thinning in chronic optic nerve injury. At presentation, swelling of the pRNFL confounds evaluation of early axon loss.

OBJECTIVE

We studied whether the GCL+IPL thins before the pRNFL, the trajectory of GCL+IPL loss and relationship to vision.

METHODS

We prospectively evaluated 33 eyes (study) with new optic neuritis, using perimetry and SD-OCT with investigative three-dimensional layer segmentation and commercial two-dimensional segmentation to compute the GCL+IPL and pRNFL thickness.

RESULTS

At presentation, GCL+IPL thickness (82.4±8.8 µm) did not differ from unaffected fellow eyes (81.2±6.7 µm), via the three-dimensional method, while the two-dimensional method failed in 9% of study eyes. At 1-2 months, there was thinning of the pRNFL in 10% and of the GCL+IPL in 93% of study eyes. GCL+IPL reduction was greatest during the first 2 months. GCL+IPL thinning at 1-2 months correlated with GCL+IPL thinning at 6 months (r=0.84, P=0.01) and presentation visual acuity (r=0.48, P=0.006) and perimetric mean deviation (r=0.52, P=0.003).

CONCLUSION

GGL+IPL is an early biomarker of structural injury in optic neuritis as thinning develops within 1-2 months of onset, prior to pRNFL thinning.

Treatment of optic neuritis with erythropoietin (TONE): a randomised, double-blind, placebo-controlled trial-study protocol

INTRODUCTION

Optic neuritis leads to degeneration of retinal ganglion cells whose axons form the optic nerve. The standard treatment is a methylprednisolone pulse therapy. This treatment slightly shortens the time of recovery but does not prevent neurodegeneration and persistent visual impairment. In a phase II trial performed in preparation of this study, we have shown that erythropoietin protects global retinal nerve fibre layer thickness (RNFLT-G) in acute optic neuritis; however, the preparatory trial was not powered to show effects on visual function.

METHODS AND ANALYSIS

Treatment of Optic Neuritis with Erythropoietin (TONE) is a national, randomised, double-blind, placebo-controlled, multicentre trial with two parallel arms. The primary objective is to determine the efficacy of erythropoietin compared to placebo given add-on to methylprednisolone as assessed by measurements of RNFLT-G and low-contrast visual acuity in the affected eye 6 months after randomisation. Inclusion criteria are a first episode of optic neuritis with decreased visual acuity to ≤ 0.5 (decimal system) and an onset of symptoms within 10 days prior to inclusion. The most important exclusion criteria are history of optic neuritis or multiple sclerosis or any ocular disease (affected or non-affected eye), significant hyperopia, myopia or astigmatism, elevated blood pressure, thrombotic events or malignancy. After randomisation, patients either receive 33,000 international units human recombinant erythropoietin intravenously for 3 consecutive days or placebo (0.9% saline) administered intravenously. With an estimated power of 80%, the calculated sample size is 100 patients. The trial started in September 2014 with a planned recruitment period of 30 months.

ETHICS AND DISSEMINATION

TONE has been approved by the Central Ethics Commission in Freiburg (194/14) and the German Federal Institute for Drugs and Medical Devices (61-3910-4039831). It complies with the Declaration of Helsinki, local laws and ICH-GCP.

TRIAL REGISTRATION NUMBER

NCT01962571.