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

Treatment With Erythropoietin for Patients With Optic Neuritis: Long-term Follow-up

BACKGROUND AND OBJECTIVE

Erythropoietin (EPO) is a candidate neuroprotective drug. We assessed its long-term safety and efficacy as an adjunct to methylprednisolone in patients with optic neuritis and focused on conversions to multiple sclerosis (MS).

METHODS

The TONE trial randomized 108 patients with acute optic neuritis but without previously known MS to either 33,000 IU EPO or placebo in conjunction with 1,000 mg methylprednisolone daily for 3 days. After reaching the primary end point at 6 months, we conducted an open-label follow-up 2 years after randomization.

RESULTS

The follow-up was attended by 83 of 103 initially analyzed patients (81%). There were no previously unreported adverse events. The adjusted treatment difference of peripapillary retinal nerve fiber layer atrophy in relation to the fellow eye at baseline was 1.27 µm (95% CI -6.45 to 8.98, p = 0.74). The adjusted treatment difference in low-contrast letter acuity was 2.87 on the 2.5% Sloan chart score (95% CI -7.92 to 13.65). Vision-related quality of life was similar in both treatment arms (National Eye Institute Visual Functioning Questionnaire median score [IQR]: 94.0 [88.0 to 96.9] in the EPO and 93.4 [89.5 to 97.4] in the placebo group). The rate of multiple sclerosis-free survival was 38% in the placebo and 53% in the EPO group (hazard ratio: 1.67, 95% CI 0.96 to 2.88, p = 0.068).

DISCUSSION

In line with the results at 6 months, we found neither structural nor functional benefits in the visual system of patients with optic neuritis as a clinically isolated syndrome, 2 years after EPO administration. Although there were fewer early conversions to MS in the EPO group, the difference across the 2-year window was not statistically significant.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that for patients with acute optic neuritis, EPO as an adjunct to methylprednisolone is well tolerated and does not improve long-term visual outcomes.

TRIAL REGISTRATION INFORMATION

The trial was preregistered before commencement at clinicaltrials.gov (NCT01962571).

Increased Remyelination and Proregenerative Microglia Under Siponimod Therapy in Mechanistic Models

Background and Objectives

Siponimod is an oral, selective sphingosine-1-phosphate receptor-1/5 modulator approved for treatment of multiple sclerosis.

Methods

Mouse MRI was used to investigate remyelination in the cuprizone model. We then used a conditional demyelination Xenopus laevis model to assess the dose-response of siponimod on remyelination. In experimental autoimmune encephalomyelitis–optic neuritis (EAEON) in C57Bl/6J mice, we monitored the retinal thickness and the visual acuity using optical coherence tomography and optomotor response. Optic nerve inflammatory infiltrates, demyelination, and microglial and oligodendroglial differentiation were assessed by immunohistochemistry, quantitative real-time PCR, and bulk RNA sequencing.

Results

An increased remyelination was observed in the cuprizone model. Siponimod treatment of demyelinated tadpoles improved remyelination in comparison to control in a bell-shaped dose-response curve. Siponimod in the EAEON model attenuated the clinical score, reduced the retinal degeneration, and improved the visual function after prophylactic and therapeutic treatment, also in a bell-shaped manner. Inflammatory infiltrates and demyelination of the optic nerve were reduced, the latter even after therapeutic treatment, which also shifted microglial differentiation to a promyelinating phenotype.

Discussion

These results confirm the immunomodulatory effects of siponimod and suggest additional regenerative and promyelinating effects, which follow the dynamics of a bell-shaped curve with high being less efficient than low concentrations.

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).

Remyelination therapies for multiple sclerosis: optimizing translation from animal models into clinical trials

Introduction: Multiple sclerosis (MS) is the most common inflammatory disease of the central nervous system (CNS). Demyelination, the main pathology in MS, contributes to clinical symptoms and long-term neurological deficits if left untreated. Remyelination, the natural repair of damaged myelin by cells of the oligodendrocyte lineage, occurs in MS, but eventually fails in most patients as they age. Encouraging timely remyelination can restore axon conduction and minimize deficits.Areas covered: We discuss and correlate human MS pathology with animal models, propose methods to deplete resident oligodendrocyte progenitor cells (OPCs) to determine whether mature oligodendrocytes support remyelination, and review remyelinating agents, mechanisms of action, and available clinical trial data.Expert opinion: The heterogeneity of human MS may limit successful translation of many candidate remyelinating agents; some patients lack the biological targets necessary to leverage current approaches. Development of therapeutics for remyelination has concentrated almost exclusively on mobilization of innate OPCs. However, mature oligodendrocytes appear an important contributor to remyelination in humans. Limiting the contribution of OPC mediated repair in models of MS would allow the evaluation of remyelination-promoting agents on mature oligodendrocytes. Among remyelinating reagents reviewed, only rHIgM22 targets both OPCs and mature oligodendrocytes.

Failed, Interrupted, or Inconclusive Trials on Neuroprotective and Neuroregenerative Treatment Strategies in Multiple Sclerosis: Update 2015-2020

In the recent past, a plethora of drugs have been approved for the treatment of multiple sclerosis (MS). These therapeutics are mainly confined to immunomodulatory or immunosuppressive strategies but do not sufficiently address remyelination and neuroprotection. However, several neuroregenerative agents have shown potential in pre-clinical research and entered Phase I to III clinical trials. Although none of these compounds have yet proceeded to approval, understanding the causes of failure can broaden our knowledge about neuroprotection and neuroregeneration in MS. Moreover, most of the investigated approaches are characterised by consistent mechanisms of action and proved convincing efficacy in animal studies. Therefore, learning from their failure will help us to enforce the translation of findings acquired in pre-clinical studies into clinical application. Here, we summarise trials on MS treatment published since 2015 that have either failed or were interrupted due to a lack of efficacy, adverse events, or for other reasons. We further outline the rationale underlying these drugs and analyse the background of failure to gather new insights into MS pathophysiology and optimise future study designs. For conciseness, this review focuses on agents promoting remyelination and medications with primarily neuroprotective properties or unconventional approaches. Failed clinical trials that pursue immunomodulation are presented in a separate article.

Erythropoietin in Lupus: Unanticipated Immune Modulating Effects of a Kidney Hormone

Systemic lupus erythematosus (SLE) is a multiorgan autoimmune disease with variable clinical presentation, typically characterized by a relapsing-remitting course. SLE has a multifactorial pathogenesis including genetic, environmental, and hormonal factors that lead to loss of tolerance against self-antigens and autoantibody production. Mortality in SLE patients remains significantly higher than in the general population, in part because of the limited efficacy of available treatments and the associated toxicities. Therefore, novel targeted therapies are urgently needed to improve the outcomes of affected individuals. Erythropoietin (EPO), a kidney-produced hormone that promotes red blood cell production in response to hypoxia, has lately been shown to also possess non-erythropoietic properties, including immunomodulatory effects. In various models of autoimmune diseases, EPO limits cell apoptosis and favors cell clearance, while reducing proinflammatory cytokines and promoting the induction of regulatory T cells. Notably, EPO has been shown to reduce autoimmune response and decrease disease severity in mouse models of SLE. Herein, we review EPO's non-erythropoietic effects, with a special focus on immune modulating effects in SLE and its potential clinical utility.

Signaling Through the Erythropoietin Receptor Affects Angiogenesis in Retinovascular Disease

Purpose

Exogenous erythropoietin (EPO) is being considered for tissue protection and angiogenesis in retinal vascular diseases. However, studies are limited by insufficient tools to address signaling effects through the EPO receptor (EPOR). We used a humanized mouse model of hypoactive EPOR signaling to test the hypothesis that EPOR signaling supports angiogenesis in retinovascular diseases.

Methods

Humanized Knockin EPOR mice (hWtEPOR) with hypoactive EPOR signaling were compared to littermate wild-type mice (WT). Postnatal day (p)7 mice of each genotype were exposed to 75% oxygen for five days, followed by 21% oxygen in the oxygen-induced retinopathy model (OIR) and compared to room-air (RA)–raised pups. At time points after OIR, pups were sacrificed, and flat-mounted, lectin-stained retinas were analyzed for central avascular area or intravitreal neovascular area (IVNV). Flash-frozen retinas were analyzed for angiogenic protein (Epo, VEGF, p-Stat3) and gene (Vegfa, Kdr, Epo, Hif1α, Hif2α) expression levels.

Results

In OIR, hWtEPOR mice had increased AVA compared with WT at p8, p12, and p17, but there was no difference in IVNV between hWtEPOR and WT mice at p17. Although VEGF and p-STAT3 proteins were increased in WT at p17 OIR, there were no differences in retinal angiogenic factor expression levels between hWtEPOR and WT OIR at p17 despite similar areas of IVNV.

Conclusions

Our data support the hypothesis that EPOR signaling was associated with regrowth of vascularization following oxygen-induced capillary dropout and played a role in intravitreal angiogenesis. Additional study of EPOR signaling regulation on other angiogenic factor pathways may be considered.

Systematic review and meta-analysis of the development of multiple sclerosis in clinically isolated syndrome

Clinically isolated syndrome (CIS) usually describes a first clinical episode that suggest multiple sclerosis. One of the signs and symptoms of CIS is Optic neuritis (ON). Several early intervention drugs are being tested in clinical trials for the early intervention in CIS patients which may lead to multiple sclerosis (MS). This study aim (1) early intervention of the CIS progression to MS delay slow down the MS progression, (2) since that ON affects 30%-70% of MS patients, the available ON intervention delay the MS progression. PubMed was used as a search engine. Summary relative risks (RRs) and 95 % confidence intervals (CIs) were estimated using a random-effect model. For aim 1, it showed lower risk of progression to MS compared to non-treated group (Risk Ratio (RR) 0.64; 95%CI: 0.58, 0.69; p < 0.001). For aim 2, drug treated group showed lower risk of progression compared to non-treated group (RR 0.19, 95%CI: 0.06, 0.54, p < 0.002. Statistical heterogeneity was not significant in both outcomes and bias of publication was not found using inspection of funnel plot and Egger's statistical test in both outcomes. In conclusion, early treatment should be considered in CIS patients to prevent the progression of MS. Moreover, this data shows that early intervention (Erythropoietin, Ery) of ON decreases the conversion risk to MS.

Current Recommendations on Optic Neuritis

BACKGROUND

Optic neuritis is a special challenge to the ophthalmologist. It is a relatively frequent condition but difficult to seize morphologically. It has neurological implications and is subject matter of recent trials.

METHODS

Selective literature search including the authors' professional experience.

RESULTS

Practical aids for the ophthalmological management of optic neuritis are derived from the best available evidence and the recent literature is discussed.

CONCLUSIONS

The present paper provides evidence-based recommendations for a safe handling of optic neuritis as well as information on current issues.

Axonal Degeneration Independent of Inflammatory Activity: Is It More Intense in the Early Stages of Relapsing-Remitting Multiple Sclerosis Disease?

BACKGROUND

This study aimed to investigate whether there are differences in the axonal degeneration rate between patients in the early years of relapsing-remitting multiple sclerosis (RRMS) disease and RRMS patients in their later years.

METHODS

The early-stage RRMS patients (EMS) group had 65 patients whose duration of disease was within 3 years from the date of the first attack. The late-stage RRMS patients (LMS) group had 69 patients whose duration of disease was within the range of 3-10 years from the date of the first attack. In addition, a control group was composed of 32 healthy subjects. Peripapillary retinal nerve fiber layer (RNFL) thickness was monitored with spectral-domain OCT in all included patients for approximately 3 years.

RESULTS

The annual RNFL atrophy rate (aRNFLr) in the EMS group was -1.246 ± 0.778 μm/year, the aRNFLr in the LMS group was -0.898 ± 0.536 μm/year, and the aRNFLr was -0.234 ± 0.154 μm/year in the control group (p < 0.001). The aRNFLr in the EMS group was significantly higher than the aRNFLr in the LMS group (p = 0.01). The aRNFLr was not associated with MRI activity or the condition of having an attack. There was a correlation between Expanded Disability Status Scale (EDSS) progression and aRNFLr in both the EMS and LMS patient groups (r = -0.471, p < 0.001, and r = -0.567, p < 0.001, respectively).

CONCLUSION

The axonal degeneration rate is faster in RRMS patients in the first years of the disease than in later years. In addition, axonal degeneration occurs independently of inflammatory activity. Axonal degeneration is correlated with disability progression, but not with inflammatory findings, such as clinical episodes and MRI activity.

Visualizing the Central Nervous System: Imaging Tools for Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) are autoimmune central nervous system conditions with increasing incidence and prevalence. While MS is the most frequent inflammatory CNS disorder in young adults, NMOSD is a rare disease, that is pathogenetically distinct from MS, and accounts for approximately 1% of demyelinating disorders, with the relative proportion within the demyelinating CNS diseases varying widely among different races and regions. Most immunomodulatory drugs used in MS are inefficacious or even harmful in NMOSD, emphasizing the need for a timely and accurate diagnosis and distinction from MS. Despite distinct immunopathology and differences in disease course and severity there might be considerable overlap in clinical and imaging findings, posing a diagnostic challenge for managing neurologists. Differential diagnosis is facilitated by positive serology for AQP4-antibodies (AQP4-ab) in NMOSD, but might be difficult in seronegative cases. Imaging of the brain, optic nerve, retina and spinal cord is of paramount importance when managing patients with autoimmune CNS conditions. Once a diagnosis has been established, imaging techniques are often deployed at regular intervals over the disease course as surrogate measures for disease activity and progression and to surveil treatment effects. While the application of some imaging modalities for monitoring of disease course was established decades ago in MS, the situation is unclear in NMOSD where work on longitudinal imaging findings and their association with clinical disability is scant. Moreover, as long-term disability is mostly attack-related in NMOSD and does not stem from insidious progression as in MS, regular follow-up imaging might not be useful in the absence of clinical events. However, with accumulating evidence for covert tissue alteration in NMOSD and with the advent of approved immunotherapies the role of imaging in the management of NMOSD may be reconsidered. By contrast, MS management still faces the challenge of implementing imaging techniques that are capable of monitoring progressive tissue loss in clinical trials and cohort studies into treatment algorithms for individual patients. This article reviews the current status of imaging research in MS and NMOSD with an emphasis on emerging modalities that have the potential to be implemented in clinical practice.

Emerging myelin repair agents in preclinical and early clinical development for the treatment of multiple sclerosis

INTRODUCTION

Remyelination is a highly effective regenerative process that can restore axon function, prevent axonal loss, and reverse clinical deficits after demyelination. Hence, the promotion of remyelination is a logical goal in patients with multiple sclerosis (MS) in which remyelination is often insufficient. However, despite great progress regarding the development of immunomodulatory therapies for MS and an abundance of promising evidence from preclinical experiments so far, no therapy has convincingly demonstrated clinically significant remyelination properties. Therefore, enhancing myelin repair is an urgent and unmet need in MS.

AREAS COVERED

We searched clinicaltrials.gov and pubmed.ncbi.nlm.nih.gov and focused on therapeutic agents in development from the preclinical stage to clinical phase II. We selected agents for which data are available from in vitro experiments and at least one toxic demyelination animal model that reached at least phase I in clinical development in MS patients.

EXPERT OPINION

The evidence to promote remyelination is very promising for several agents, some of which possess anti-muscarinergic properties. Since remyelination is a complex process that involves various coordinated steps, a combination of different therapeutic approaches addressing different aspects of this regenerative mechanism may be reasonable. Furthermore, suitable surrogate markers of remyelination are necessary for proof-of-concept clinical trials.

Assessing the anterior visual pathway in optic neuritis: recent experimental and clinical aspects

PURPOSE OF REVIEW

Multiple sclerosis (MS) and related autoimmune disorders of the central nervous system such as neuromyelitis optica spectrum disorders (NMOSD) are characterized by chronic disability resulting from autoimmune neuroinflammation, with demyelination, astrocyte damage, impaired axonal transmission and neuroaxonal loss. Novel therapeutics stopping or reversing the progression of disability are still urgently warranted. This review addresses research on optic neuritis in preclinical experimental models and their translation to clinical trials.

RECENT FINDINGS

Optic neuritis can be used as paradigm for an MS relapse which can serve to evaluate the efficacy of novel therapeutics in clinical trials with a reasonable duration and cohort size. The advantage is the linear structure of the visual pathway allowing the assessment of visual function and retinal structure as highly sensitive outcome parameters. Experimental autoimmune encephalomyelitis is an inducible, inflammatory and demyelinating central nervous system disease extensively used as animal model of MS. Optic neuritis is part of the clinicopathological manifestations in a number of experimental autoimmune encephalomyelitis models. These have gained increasing interest for studies evaluating neuroprotective and/or remyelinating substances as longitudinal, visual and retinal readouts have become available.

SUMMARY

Translation of preclinical experiments, evaluating neuroprotective or remyelinating therapeutics to clinical studies is challenging. In-vivo readouts like optical coherence tomography, offers the possibility to transfer experimental study designs to clinical optic neuritis trials.

Erythropoietin Receptor Signaling Supports Retinal Function after Vascular Injury

The investigation of erythropoietin (EPO) has expanded to include potential nonhematopoietic roles in neural and retinal diseases, including diabetic retinopathy. However, it remains unclear how EPO functions to support the neural retina. Transgenic mice with hypoactive EPO receptor (EPOR) signaling (hWtEPOR) were compared with littermate control mice (WT) to test the role of EPOR signaling under normal conditions and after vascular injury and regrowth into the retina. Although retinal function tested with OptoMotry and electroretinography was comparable to adult (8-week-old) littermate WT mice, hWtEPOR mice had thinner inner and outer plexiform layers and a greater number of amacrine cells. Injury and repair caused by the oxygen-induced retinopathy model reduced visual acuity thresholds, reduced electroretinography amplitudes, and thinned the outer plexiform and inner nuclear layers of both WT and hWtEPOR 8-week-old mice. In hWtEPOR compared with WT mice, scotopic a-wave amplitudes were reduced by injury, despite no change in outer nuclear layer thickness; and peripheral rod, but not cone number, was reduced. Scotopic b-waves were reduced in injured hWtEPOR mice compared with WT, and rod bipolar cell ectopic neurites were increased in both genotypes after injury, suggesting a potential reparative process to preserve connectivity and the b-wave. Normal EPOR signaling appeared important because ectopic neurites and b-waves were lower in the hWtEPOR than WT injured mice.

Change in visual acuity and retinal structures following Repository Corticotropin Injection (RCI) therapy in patients with acute demyelinating optic neuritis: Improvement in low contrast visual acuity in both affected and contralateral eyes in a single-armed open-label study

BACKGROUND

Current treatments after an episode of optic neuritis have limited success protecting the retinal nerves and restoring visual function.

OBJECTIVE

To assess the effectiveness of Repository Corticotropin Injection (RCI) after the onset of optic neuritis.

METHODS

Twenty-four adults were treated with RCI within 2 weeks of symptom onset. Seven exams over 400 days measured low- and high-contrast visual acuity (LCVA and HCVA) and spectral domain optical coherence tomography of the retinal structures. Differences between and among affected and contralateral eyes were assessed using linear mixed models.

RESULTS

HCVA improved in the affected eye over the study (36.2 letters to 52.5), and LCVA improved in both the affected eye (1.8 letters to 6.8) and the contralateral eye (8.3 letters to 11.7). These functional improvements occurred concurrent to a thinning in the papillomacular bundle and the ganglion cell, inner plexiform, and retinal nerve fiber layers, while the inner nuclear, outer plexiform, outer nuclear, and photoreceptor layers thickened.

CONCLUSION

The eyes affected by the ON and treated with RCI improved in both LCVA and HCVA, and unexpectedly LCVA improved in the contralateral eye as well. This functional improvement was mirrored by structural changes in the retina. This study lays the groundwork for future studies to explore potential neuro-protective and neuro-restorative effects of RCI.

Monitoring retinal changes with optical coherence tomography predicts neuronal loss in experimental autoimmune encephalomyelitis

Background

Retinal optical coherence tomography (OCT) is a clinical and research tool in multiple sclerosis, where it has shown significant retinal nerve fiber (RNFL) and ganglion cell (RGC) layer thinning, while postmortem studies have reported RGC loss. Although retinal pathology in experimental autoimmune encephalomyelitis (EAE) has been described, comparative OCT studies among EAE models are scarce. Furthermore, the best practices for the implementation of OCT in the EAE lab, especially with afoveate animals like rodents, remain undefined. We aimed to describe the dynamics of retinal injury in different mouse EAE models and outline the optimal experimental conditions, scan protocols, and analysis methods, comparing these to histology to confirm the pathological underpinnings.

Methods

Using spectral-domain OCT, we analyzed the test-retest and the inter-rater reliability of volume, peripapillary, and combined horizontal and vertical line scans. We then monitored the thickness of the retinal layers in different EAE models: in wild-type (WT) C57Bl/6J mice immunized with myelin oligodendrocyte glycoprotein peptide (MOG_35–55) or with bovine myelin basic protein (MBP), in TCR^2D2 mice immunized with MOG_35–55, and in SJL/J mice immunized with myelin proteolipid lipoprotein (PLP_139–151). Strain-matched control mice were sham-immunized. RGC density was counted on retinal flatmounts at the end of each experiment.

Results

Volume scans centered on the optic disc showed the best reliability. Retinal changes during EAE were localized in the inner retinal layers (IRLs, the combination of the RNFL and the ganglion cell plus the inner plexiform layers). In WT, MOG_35–55 EAE, progressive thinning of IRL started rapidly after EAE onset, with 1/3 of total loss occurring during the initial 2 months. IRL thinning was associated with the degree of RGC loss and the severity of EAE. Sham-immunized SJL/J mice showed progressive IRL atrophy, which was accentuated in PLP-immunized mice. MOG_35–55-immunized TCR^2D2 mice showed severe EAE and retinal thinning. MBP immunization led to very mild disease without significant retinopathy.

Conclusions

Retinal neuroaxonal damage develops quickly during EAE. Changes in retinal thickness mirror neuronal loss and clinical severity. Monitoring of the IRL thickness after immunization against MOG_35–55 in C57Bl/6J mice seems the most convenient model to study retinal neurodegeneration in EAE.

Optical coherence tomography and multiple sclerosis: Update on clinical application and role in clinical trials

Optical coherence tomography (OCT) has emerged as a fast, non-invasive, inexpensive, high-resolution imaging technique in multiple sclerosis (MS). Retinal layer quantification by OCT facilitates a 'window' into not only local retinal pathology but also global neurodegenerative processes, recognised to be the principal substrates of disability accumulation in MS. While OCT measures in MS have been demonstrated to reflect visual function, inflammatory activity outside of the visual pathways, disability measures including the prediction of disability progression, whole brain atrophy, and the differential neuroprotective effects of disease-modifying therapies, debate continues regarding the clinical utility of OCT in everyday practice. This review presents an overview of the evidence supporting OCT, with particular focus on its application in the MS clinic. We will also discuss the role of OCT in MS clinical trials to develop novel neuroprotective and potential remyelinating therapies.

[Optical coherence tomography in neuromyelitis optica spectrum disorders]

Neuromyelitis optica spectrum disorders (NMOSD) are mostly relapsing inflammatory conditions of the central nervous system (CNS). In 55% of the cases of NMOSD optic neuritis (ON) is the most frequent first manifestation and can cause severe damage to the afferent visual system and the retina with resultant severe visual impairment. In recent years, investigations of the retina as part of the CNS by optical coherence tomography (OCT) has been shown to be a valid and efficient method for diagnostics and evaluation of the disease course in NMOSD. In addition, OCT not only shows severe damage of the afferent visual system due to multiple bouts of ON but also reveals NMOSD-specific intraretinal pathologies. The latter could be just as important for future differential diagnostics as for the evaluation of potential therapeutic targets. This article briefly reviews the principles of the OCT technique and describes its relevance for the diagnostics and assessment of disease course in NMOSD.

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.

Leukemia inhibitory factor inhibits erythropoietin-induced myelin gene expression in oligodendrocytes

Background

The pro-myelinating effects of leukemia inhibitory factor (LIF) and other cytokines of the gp130 family, including oncostatin M (OSM) and ciliary neurotrophic factor (CNTF), have long been known, but controversial results have also been reported. We recently overexpressed erythropoietin receptor (EPOR) in rat central glia-4 (CG4) oligodendrocyte progenitor cells (OPCs) to study the mechanisms mediating the pro-myelinating effects of erythropoietin (EPO). In this study, we investigated the effect of co-treatment with EPO and LIF.

Methods

Gene expression in undifferentiated and differentiating CG4 cells in response to EPO and LIF was analysed by DNA microarrays and by RT-qPCR. Experiments were performed in biological replicates of N ≥ 4. Functional annotation and biological term enrichment was performed using DAVID (Database for Annotation, Visualization and Integrated Discovery). The gene-gene interaction network was visualised using STRING (Search Tool for the Retrieval of Interacting Genes).

Results

In CG4 cells treated with 10 ng/ml of EPO and 10 ng/ml of LIF, EPO-induced myelin oligodendrocyte glycoprotein (MOG) expression, measured at day 3 of differentiation, was inhibited ≥4-fold (N = 5, P < 0.001). Inhibition of EPO-induced MOG was also observed with OSM and CNTF. Analysis of the gene expression profile of CG4 differentiating cells treated for 20 h with EPO and LIF revealed LIF inhibition of EPO-induced genes involved in lipid transport and metabolism, previously identified as positive regulators of myelination in this system. In addition, among the genes induced by LIF, and not by differentiation or by EPO, the role of suppressor of cytokine signaling 3 (SOCS3) and toll like receptor 2 (TLR2) as negative regulators of myelination was further explored. LIF-induced SOCS3 was associated with MOG inhibition; Pam3, an agonist of TLR2, inhibited EPO-induced MOG expression, suggesting that TLR2 is functional and its activation decreases myelination.

Conclusions

Cytokines of the gp130 family may have negative effects on myelination, depending on the cytokine environment.

Electronic supplementary material

The online version of this article (10.1186/s10020-018-0052-3) contains supplementary material, which is available to authorized users.

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.

Using the Anterior Visual System to Assess Neuroprotection and Remyelination in Multiple Sclerosis Trials

PURPOSE OF REVIEW

Clinical trials using agents directed at neuroprotection and remyelination in multiple sclerosis (MS) are needed. As optic neuritis (ON) is common in people with MS and the pathology of ON is similar to other MS lesions in the brain, measurements of the anterior visual system are frequently utilized in neuroprotection and remyelination trials. Understanding the strengths and weaknesses of the measurements is vital when interpreting the results of this research.

RECENT FINDINGS

Techniques such as visual evoked potentials (VEP) and optical coherence tomography (OCT) are well established in MS and are thought to measure axonal integrity and myelination. Novel imaging techniques can also be used in conjunction with these measurements to provide better insight into optic nerve structure and function. Magnetization transfer imaging (MTR) together with optic nerve area and volume measures neurodegeneration; diffusion tensor imaging (DTI) measures myelination status and neurodegeneration. However, these techniques require various levels of experience to interpret, and all can be confounded by ocular motion and surrounding fat and bone. This article provides a review of established and novel techniques to measure the anterior visual system in multiple sclerosis with a focus on the evidence to support their use as outcome measures in clinical trials focused on neuroprotection and remyelination therapies.

Optical coherence tomography in neuromyelitis optica spectrum disorders: potential advantages for individualized monitoring of progression and therapy

Neuromyelitis optica spectrum disorders (NMOSD) are mostly relapsing inflammatory disorders of the central nervous system (CNS). Optic neuritis (ON) is the first NMOSD-related clinical event in 55% of the patients, which causes damage to the optic nerve and leads to visual impairment. Retinal optical coherence tomography (OCT) has emerged as a promising method for diagnosis of NMOSD and potential individual monitoring of disease course and severity. OCT not only detects damage to the afferent visual system caused by ON but potentially also NMOSD-specific intraretinal pathology, i.e. astrocytopathy. This article summarizes retinal involvement in NMOSD and reviews OCT methods that could be used now and in the future, for differential diagnosis, for monitoring of disease course, and in clinical trials.

Optic neuritis: the eye as a window to the brain

PURPOSE OF REVIEW

Acute optic neuritis is a common clinical problem, requiring a structured assessment to guide management and prevent visual loss. The optic nerve is the most accessible part of the central nervous system, so optic neuritis also represents an important paradigm to help decipher mechanisms of damage and recovery in the central nervous system. Important developments include the advent of optical coherence tomography as a biomarker of central nervous system axonal loss, the discovery of new pathological antibodies, notably against aquaporin-4 and, more recently, myelin oligodendrocyte protein, and emerging evidence for sodium channel blockade as a novel therapeutic approach to address energy failure in neuroinflammatory disease.

RECENT FINDINGS

We will present a practical approach to assessment of optic neuritis, highlighting the role of optical coherence tomography, when to test for new antibodies and the results of recent trials of sodium channel blockers.

SUMMARY

Optic neuritis remains a clinical diagnosis; increasingly optical coherence tomography is a key ancillary investigation. Patients with 'typical' optic neuritis, commonly a first presentation of multiple sclerosis, must be distinguished from 'atypical' optic neuritis, who require testing for new pathological antibodies and require more aggressive-targeted treatment. Sodium channel blockade is an emerging and novel potential therapeutic pathway in neuroinflammatory disease.

Neuroprotection and visual function after optic neuritis

PURPOSE OF REVIEW

This article discusses the advantages and pitfalls of testing neuroprotective treatment strategies in patients suffering from optic neuritis.

RECENT FINDINGS

Spectral domain optical coherence tomography now permits for automated segmentation of individual retinal layers. The peripapillary retinal nerve fibre layer (pRNFL) has been used in 13 of the 15 trials reviewed. Twelve trials also made use of electrophysiology. Overestimation of good visual recovery in the past has recently been recognized. Assessment of low contrast visual acuity and colour vision are now mainstream.

SUMMARY

The availability of highly accurate and robust trial outcome measures has facilitated research on this topic. A single long-term structural outcome measurement of the pRNFL is sufficient. For shorter term, assessments of the ganglion cell/inner plexiform layer and axonal birefringence are promising. Longitudinal blood levels of neurofilament proteins permit to recognize axonal loss at presentation and monitor changes longitudinally. Inner nuclear layer volume changes relate to inflammatory disease activity.Pitfalls are related to the timing of events. Hyperacute recruitment is needed for future trials. The onset of demyelination is not known, which complicates timing of electrophysiological recordings. Optic disc oedema precludes the use of the pRNFL from the affected eye as a baseline variable. The concomitant use of corticosteroids complicates interpretation of trial data.

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.

Neuroprotective effects of erythropoietin on rat retinas subjected to oligemia

OBJECTIVES

Erythropoietin may have neuroprotective potential after ischemia of the central nervous system. Here, we conducted a study to characterize the protective effects of erythropoietin on retinal ganglion cells and gliotic reactions in an experimentally induced oligemia model.

METHODS

Rats were subjected to global oligemia by bilateral common carotid artery occlusion and then received either vehicle or erythropoietin via intravitreal injection after 48 h; they were euthanized one week after the injection. The densities of retinal ganglion cells and contents of glial fibrillary acidic protein (astrocytes/Müller cells) and cluster of differentiation 68 clone ED1 (microglia/macrophages), assessed by fluorescence intensity, were evaluated in frozen retinal sections by immunofluorescence and epifluorescence microscopy.

RESULTS

Retinal ganglion cells were nearly undetectable one week after oligemia compared with the sham controls; however, these cells were partially preserved in erythropoietin-treated retinas. The contents of glial fibrillary acidic protein and cluster of differentiation 68 clone ED1, markers for reactive gliosis, were significantly higher in retinas after bilateral common carotid artery occlusion than those in both sham and erythropoietin-treated retinas.

CONCLUSIONS

The number of partially preserved retinal ganglion cells in the erythropoietin-treated group suggests that erythropoietin exerts a neuroprotective effect on oligemic/ischemic retinas. This effect could be related to the down-modulation of glial reactivity, usually observed in hypoxic conditions, clinically observed during glaucoma or retinal artery occlusion conditions. Therefore, glial reactivity may enhance neurodegeneration in hypoxic conditions, like normal-tension glaucoma and retinal ischemia, and erythropoietin is thus a candidate to be clinically applied after the detection of decreased retinal blood flow.

Vascular hypoperfusion in acute optic neuritis is a potentially new neurovascular model for demyelinating diseases

PURPOSE

Optic neuritis is highly correlated with multiple sclerosis and is a major cause of acute visual loss and long-term neuronal degeneration. Primary cerebral hypoperfusion has been reported in brain demyelinating diseases. This study investigated whether peripapillary perfusion is changed in patients with acute optic neuritis (AON).

METHODS

This three-year cohort study was conducted from September 1 2012, to August 31, 2015. Two hundred and forty-one patients with non-glaucomatous acute optic neuropathy were screened, and 42 non-highly myopic patients who had suffered their first episode of unilaterally idiopathic AON were studied. All cases received spectral-domain optical coherence tomography (OCT) examination, general survey, and standard corticosteroid therapy. OCT images were analyzed using a customized MATLAB program for measuring peripapillary choroidal thickness (PCT). Multivariate regression models were constructed to identify factors that are significantly related to peripapillary perfusion.

RESULTS

Decreased PCT was found in eyes experiencing AON combined with disc swelling (the ratio of lesion eye PCT/fellow eye PCT was 0.87 ± 0.08; range, from 0.75 to 1.00). In comparison to the healthy fellow eyes, approximately every 26% increase in the thickness of the retinal nerve fiber layer due to axonal swelling was associated with a 10% decreased thickness of PCT. Thinner PCT is also correlated with poorer trough vision, which may lead to poorer final vision. These findings were obvious in patients with optic papillitis but not in patients with retrobulbar neuritis.

CONCLUSIONS

Peripapillary vascular hypoperfusion was found in patients experiencing AON combined with disc swelling. These findings are unlike those for other ocular inflammatory diseases but are consistent with cerebral hypoperfusion, which is found in brain demyelinating diseases; thus, these findings may represent a new neurovascular model in this field.

Evaluation of the effect of erythropoietin + corticosteroid versus corticosteroid alone in methanol-induced optic nerve neuropathy

PURPOSE

Following methanol intoxication, optic nerve neuropathy may occur, which is currently treated by different therapeutic regimens. Erythropoietin (EPO) has recently been introduced as a good therapeutic option in methanol-induced optic neuropathy. The aim of the current study was to evaluate the efficacy of EPO in improvement of the visual disturbances in methanol-intoxicated patients.

MATERIALS AND METHODS

In a case-control study, all patients who had referred to our toxicology centre with confirmed diagnosis of methanol toxicity were considered to be included. Of them, those who had referred with visual disturbances, survived, and their visual disturbances had not improved after haemodialysis were entered. Cases received EPO and corticosteroids while controls only received corticosteroids. They were then compared regarding their visual outcome.

RESULTS

All five patients in the control group mentioned that after discharge, their visual acuity had improved while in the cases, three mentioned visual improvement, two mentioned their visual acuity had deteriorated after discharge, two mentioned no change in their visual acuity and three mentioned that their visual acuity had first improved but then deteriorated with a mean two-month interval period. In fundoscopic evaluations, two controls had normal fundospcopy while eight cases had abnormal fundoscopy (p = 0.055).

CONCLUSIONS

Protective effect of EPO on methanol-induced optic nerve may be strong at the beginning of the intervention but is probably transient.

Early retinal atrophy predicts long-term visual impairment after acute optic neuritis

BACKGROUND

Visual recovery after optic neuritis (ON) used to be defined as good, although patients frequently complain of poor vision.

METHODS

We carried out a prospective study on 38 consecutive patients with acute ON followed monthly for 6 months and evaluated high- and low-contrast visual acuity (HCVA and LCVA, respectively), quality of vision (National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25)), visual fields, and retinal thickness by spectral domain optical coherence tomography (OCT).

RESULTS

We found significant impaired LCVA and color vision in ON eyes 6 months after acute ON, which impact on quality of life. LCVA and color vision were correlated with the thicknesses of the ganglion cell and inner plexiform layer (GCIPL; 2.5% LCVA r = 0.65 and p = 0.0001; color vision r = 0.75 and p < 0.0001) and that of the peripapillary retinal nerve fiber layer (pRNFL; LCVA r = 0.43 and p = 0.0098; color vision r = 0.62 and p < 0.0001). Linear regression models that included the change in the GCIPL and pRNFL thicknesses from baseline to month 1 after onset explained 47% of the change in 2.5% LCVA and 67% of the change of color vision acuity. When adjusting for the value of visual acuity at baseline, predictors of the change in vision from baseline to month 6 achieved similar performance for all three types of vision (HCVA, LCVA, and color vision).

CONCLUSION

Monitoring retinal atrophy by OCT within the first month after ON onset allows individuals at a high risk of residual visual impairment to be identified.

Association between macular degeneration and mild to moderate chronic kidney disease: A nationwide population-based study

Chronic kidney disease (CKD) and macular degeneration (MD) are 2 grave diseases leading to significant disability secondary to renal failure and blindness. The 2 diseases share not only common risk factors but also similar pathogenic mechanisms to renal and retinal injuries. Previous epidemiological studies indicated association between these 2 diseases. However, this concept is challenged by recent investigations. Patients with mild to moderate CKD (n = 30,696) between January 1, 1995 and December 31, 2005 were selected from the Taiwan National Health Insurance Database. Controls (n = 122,784) were matched by age, gender, diabetes mellitus type 2, and hypertension status (1:4 ratios). The risk of MD was compared between the 2 groups. The mean age of patients was 54.9 ± 15.7 years. The proportion of MD was 2.7% in mild to moderate CKD patients and 1.9% in normal controls (P < 0.001); and, 0.39% and 0.26% (P < 0.001) in advanced MD. Mild to moderate CKD patients had higher risk for MD [adjusted odds ratio (OR), 1.301; 95% confidence interval (CI), 1.200-1.411; P < 0.001] than normal renal function subjects. The association was more pronounced for advanced MD. From all age strata (10 years increase), the presence of CKD in those patients aged less than 40 years had highest OR for all MD (OR = 2.125, 95% CI: 1.417-3.186, P < 0.001). The results were consistent in interaction terms, highlighting the importance of CKD in young age patient for risk of MD. The high risk for MD in mild to moderate CKD patients remains significant after adjustment for personal habits (alcohol drinking and smoking, model 1; OR: 1.371; 95% CI: 1.265-1.486; P < 0.001), comorbidities (dyslipidemia, cerebrovascular disease, and peripheral vascular disease, model 2; OR: 1.369; 95% CI: 1.264-1.484; P < 0.001) and all these factors (model 3; OR: 1.320, 95% CI: 1.218-1.431, P < 0.001). This association was consistent in the subanalysis, excluding those patients with diabetic retinopathy. Proper diagnosis and timely intervention should be warranted to retard visual loss of these patients.

The Effect of Combined Systemic Erythropoietin and Steroid on Non-arteritic Anterior Ischemic Optic Neuropathy: A Prospective Study

BACKGROUND

To investigate the effect of combined intravenous (IV) erythropoietin (EPO) and corticosteroid as well as systemic steroid alone for the treatment of non-arteritic anterior ischemic optic neuropathy (NAION).

METHODS

In this prospective interventional comparative case series, 113 consecutive patients diagnosed with recent onset (less than 14 days) NAION were included. Patients were categorized into three groups. 40 patients received systemic IV corticosteroid combined with recombinant human erythropoietin (rhEPO) (group 1), 43 patients received systemic corticosteroid alone (group 2), and 30 patients were enrolled as the control group (group 3). Functional and structural outcomes were analyzed 3 and 6 months after treatment. Best corrected visual acuity (BCVA) was the main outcome, and mean deviation (MD) and peripaillary retinal nerve fiber layer thickness (PRNFLT) were secondary outcome measures.

RESULTS

The mean BCVA at the time of presentation was 0.98 (±0.65), 0.96 (±0.67), and 1.02 (±0.63) log MAR in groups 1, 2, and 3, respectively (P = 0.95). At month 3, the corresponding values were 0.73 (±0.45), 0.76 (±0.49), and 0.8 (±0.45) log MAR (P = 0.80), and at the 6-month follow-up, they were 0.76 (±0.45), 0.71 (±0.4), and 0.71 (±0.46) log MAR, respectively (P = 0.87). There was no statistically significant difference in BCVA between months 3 and 6, which implies stabilization of the visual acuity by month 3. Considering the visual field, within 6 months of follow-up after disease onset, the MD index improved in all groups with no statistically significant differences between them (P = 0.82). PRNFLT at presentation was 178 (±60), 186 (±59), and 166 (±57) micrometers in groups 1, 2, and 3, respectively (P= 0.99), which decreased to 77 (±16), 83 (±22), and 73 (±11), respectively, at final visit (P = 0.14) Conclusion: We found no beneficial effect of either systemic steroid alone or combined with EPO in the visual outcome of NAION patients.

Retinal biomarkers provide "insight" into cortical pharmacology and disease

The retina is an easily accessible out-pouching of the central nervous system (CNS) and thus lends itself to being a biomarker of the brain. More specifically, the presence of neuronal, vascular and blood-neural barrier parallels in the eye and brain coupled with fast and inexpensive methods to quantify retinal changes make ocular biomarkers an attractive option. This includes its utility as a biomarker for a number of cerebrovascular diseases as well as a drug pharmacology and safety biomarker for the CNS. It is a rapidly emerging field, with some areas well established, such as stroke risk and multiple sclerosis, whereas others are still in development (Alzheimer's, Parkinson's, psychological disease and cortical diabetic dysfunction). The current applications and future potential of retinal biomarkers, including potential ways to improve their sensitivity and specificity are discussed. This review summarises the existing literature and provides a perspective on the strength of current retinal biomarkers and their future potential.