Lipoic acid in secondary progressive MS: A randomized controlled pilot trial

Rodent Models of Optic Neuritis

Optic neuritis (ON) is an inflammatory attack of the optic nerve that leads to visual disability. It is the most common optic neuropathy affecting healthy young adults, most commonly women aged 20-45 years. It can be idiopathic and monophasic or as part of a neurologic disease such as multiple sclerosis with recurrence and cumulative damage. Currently, there is no therapy to repair the damage from optic neuritis. Animal models are an essential tool for the understanding of the pathogenesis of optic neuritis and for the development of potential treatment strategies. Experimental autoimmune encephalomyelitis (EAE) is the most commonly used experimental rodent model for human autoimmune inflammatory demyelinating diseases of the central nervous system (CNS). In this review, we discuss the latest rodent models regarding optic neuritis, focusing on EAE model, and on its recent achievements and developments.

Advances in the Treatment of Multiple Sclerosis

Multiple sclerosis is a relatively common, immune-mediated neurologic disease of the central nervous system that can cause significant disability and lead to reduced quality of life. There are several currently approved disease-modifying therapies, and more in the pipeline being developed and tested. As the field learns more about the pathophysiology and natural course of the disease, the treatment approaches are also being investigated. This article reviews data on available treatments along with a discussion of future treatment targets under investigation.

Safety Evaluation of α-Lipoic Acid Supplementation: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Clinical Studies

Alpha-lipoic acid (ALA) is a natural short-chain fatty acid that has attracted great attention in recent years as an antioxidant molecule. However, some concerns have been recently raised regarding its safety profile. To address the issue, we aimed to assess ALA safety profile through a systematic review of the literature and a meta-analysis of the available randomized placebo-controlled clinical studies. The literature search included EMBASE, PubMed Medline, SCOPUS, Google Scholar, and ISI Web of Science by Clarivate databases up to 15th August 2020. Data were pooled from 71 clinical studies, comprising 155 treatment arms, which included 4749 subjects with 2558 subjects treated with ALA and 2294 assigned to placebo. A meta-analysis of extracted data suggested that supplementation with ALA was not associated with an increased risk of any treatment-emergent adverse event (all p > 0.05). ALA supplementation was safe, even in subsets of studies categorized according to smoking habit, cardiovascular disease, presence of diabetes, pregnancy status, neurological disorders, rheumatic affections, severe renal impairment, and status of children/adolescents at baseline.

Enlarged perivascular spaces are not associated with vascular co-morbidities, clinical outcomes, and brain volumes in people with secondary progressive multiple sclerosis

In secondary progressive multiple sclerosis (SPMS) significance of enlarged perivascular spaces (ePVS) is unknown.

Objectives, Methods: Analysis of associations between vascular co-morbidities, clinical outcomes, and volumetrics with categorical ePVS scores in midbrain, basal ganglia (BG), and centrum semiovale (CSO) in SPMS(n-46).

Results, Conclusion: In BG, advancing age (Z = 2.68) and lower Expanded Disability Status Scale (Z = −2.04) were associated with increasing ePVS score. In CSO, advancing age (Z = 2.66) and male gender (Z = 2.45) were associated with increasing ePVS score. No associations between ePVS score and vascular co-morbidities or volumetrics existed; ePVS may not be an informative marker for SPMS.

Lipoic acid modulates inflammatory responses of monocytes and monocyte-derived macrophages from healthy and relapsing-remitting multiple sclerosis patients

Multiple sclerosis (MS) is a disabling neuroinflammatory disease. Its etiology is unknown, but both oxidative stress and inflammation appear to be involved in disease pathology. Macrophages are the predominant cell type in acute inflammatory brain lesions in MS. Macrophages produce proinflammatory and toxic molecules that promote demyelination and are key players in phagocytosis/degradation of myelin sheathes. Lipoic acid (LA) is an inexpensive, endogenously produced small molecule that exhibits antioxidant and anti-inflammatory effects. Treatment with LA is protective in MS and other inflammatory diseases. To examine the mechanism(s) by which LA may attenuate inflammatory lesion activity in MS, we used healthy control and MS cells to evaluate the effects of LA on levels of inflammatory cytokines, phagocytosis and the immunomodulator cyclic adenosine monophosphate (cAMP) in monocytes and monocyte-derived macrophages (MDMs). LA treatment resulted in a generally less inflammatory phenotype of monocytes and MDMs from healthy controls, and (to a lesser degree) MS donors. LA inhibited monocyte secretion of cytokines relevant to MS in monocytes, including tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β; LA effects on secretion of these cytokines in MDMs were mixed with inhibition of TNF-α and IL-6, but stimulation of IL-1β, the latter perhaps as a result of altered macrophage polarization. LA inhibited phagocytosis in both monocytes and MDMs, and increased cAMP levels in monocytes. LA may modulate inflammatory cytokine secretion and phagocytosis via a cAMP-mediated mechanism.

Oxidative/Nitroxidative Stress and Multiple Sclerosis

Multiple sclerosis (MS) is a multifactorial, central nervous system, immune-mediated disease characterized by inflammation, demyelination, and neurodegeneration. Evidence suggests a steady rise in MS prevalence over the past five decades in the United States and around the world. Even with increased understanding of immunology, the specific etiological trigger of MS remains unknown. Evidence suggests that oxidative/nitroxidative stress is an important contributor to MS etiology, progression, and clinical symptoms. A multifaceted treatment approach aimed at counteracting oxidative/nitroxidative stress including MS disease-modifying medications, Mediterranean style diet, stress-relieving activities, smoking and alcohol cessation, exercise, and peer support programs is the best way to treat the disease.

The Potential Contribution of Dysfunctional RNA-Binding Proteins to the Pathogenesis of Neurodegeneration in Multiple Sclerosis and Relevant Models

Neurodegeneration in multiple sclerosis (MS) is believed to underlie disease progression and permanent disability. Many mechanisms of neurodegeneration in MS have been proposed, such as mitochondrial dysfunction, oxidative stress, neuroinflammation, and RNA-binding protein dysfunction. The purpose of this review is to highlight mechanisms of neurodegeneration in MS and its models, with a focus on RNA-binding protein dysfunction. Studying RNA-binding protein dysfunction addresses a gap in our understanding of the pathogenesis of MS, which will allow for novel therapies to be generated to attenuate neurodegeneration before irreversible central nervous system damage occurs.

Approved and Emerging Disease Modifying Therapies on Neurodegeneration in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune, chronic, progressive disease leading to a combination of inflammation, demyelination, and neurodegeneration throughout the central nervous system (CNS). The outcome of these processes can be visualized in magnetic resonance imaging (MRI) scans as brain atrophy, or brain volume loss (BVL), as well as lesions, “black holes” and spinal cord atrophy. MRI outcomes such as BVL have been used as biomarkers of neurodegeneration and other measures of MS disease progression in clinical research settings. Several FDA-approved medications seek to alleviate disease progression by reducing the impact of such factors as demyelination and neurodegeneration, but there are still many shortcomings that current clinical research aims to mitigate. This review attempts to provide an overview of the FDA-approved medications available for treating multiple sclerosis and their effect on neurodegeneration, measured by BVL.

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.

Dietary factors in experimental autoimmune encephalomyelitis and multiple sclerosis: A comprehensive review

BACKGROUND

Dietary intervention in multiple sclerosis carries potential therapeutic implications. While studies utilizing animal models of multiple sclerosis (MS) have demonstrated intriguing findings, well-designed clinical trials are few in number.

OBJECTIVE

The objective of this study is to review the animal model and clinical literature regarding dietary factors in experimental autoimmune encephalitis (EAE) and MS.

METHODS

This manuscript provides a comprehensive review of current animal model and clinical knowledge related to dietary factors in MS.

RESULTS

While there is currently little data for any specific diet in MS, there is growing evidence that certain dietary factors may influence the disease.

CONCLUSIONS

Definitive information regarding dietary factors as a modifiable risk factor in MS will require larger randomized clinical trials.

Efficacy of andrographolide in not active progressive multiple sclerosis: a prospective exploratory double-blind, parallel-group, randomized, placebo-controlled trial

BACKGROUND

Multiple sclerosis (MS) is a chronic immune mediated disease and the progressive phase appears to have significant neurodegenerative mechanisms. The classification of the course of progressive MS (PMS) has been re-organized into categories of active vs. not active inflammatory disease and the presence vs. absence of gradual disease progression. Clinical trial experience to date in PMS with anti-inflammatory medications has shown limited effect. Andrographolide is a new class of anti-inflammatory agent, that has been proposed as a potential drug for autoimmune disorders, including MS. In the present trial, we perform an exploratory pilot study on the efficacy and safety of andrographolide (AP) compared to placebo in not active PMS.

METHODS

A pilot clinical trial using 140 mg oral AP or placebo twice daily for 24 months in patients with not active primary or secondary progressive MS was conducted. The primary efficacy endpoint was the mean percentage brain volume change (mPBVC). Secondary efficacy endpoints included 3-month confirmed disability progression (3-CDP) and mean EDSS change.

RESULTS

Forty-four patients were randomized: 23 were assigned to the AP group, and 21 were assigned to the placebo group. The median baseline EDSS of both groups was 6.0. Annualized mPBVC was - 0.679% for the AP group and - 1.069% for the placebo group (mean difference: -0.39; 95% CI [- 0.836-0.055], p = 0.08, relative reduction: 36.5%). In the AP group, 30% had 3-CDP compared to 41% in the placebo group (HR: 0.596; 95% CI [0.200-1.777], p = 0.06). The mean EDSS change was - 0.025 in the AP group and + 0.352 in the placebo group (mean difference: 0.63, p = 0.042). Adverse events related to AP were mild rash and dysgeusia.

CONCLUSIONS

AP was well tolerated and showed a potential effect in reducing brain atrophy and disability progression, that need to be further evaluated in a larger clinical trial.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02273635 retrospectively registered on October 24th, 2014.

Structural Neural Correlates of Impaired Postural Control in People with Secondary Progressive Multiple Sclerosis

BACKGROUND

Secondary progressive multiple sclerosis (SPMS) is characterized by worsening of postural control and brain atrophy. However, little is known about postural deficits and their neuroanatomical correlates in this population. We aimed to determine the neuroanatomical correlates of postural deficits in people with SPMS and whether posture control deteriorates concomitantly with the brain and spinal cord atrophy in 2 years in SPMS.

METHODS

This study is a post hoc analysis of data from 27 people with SPMS (mean ± SE age, 58.6 ± 1.1 years). Participants had magnetic resonance imaging (MRI) of the brain and cervical spinal cord followed by sway testing using inertial sensors during standing with eyes open (EO) and eyes closed without (EC) and with (ECC) a cognitive task. Partial correlations investigated relationships between postural control and MRI measures at baseline and 2 years.

RESULTS

At baseline, sway measures were inversely related to cortical thickness and cord cross-sectional area (CSA) during the EO task but only to cord CSA with EC (P < .05). After 2 years, the percentage change in sway amplitude and dispersion during EO tasks significantly related to the percentage decline in cord CSA (P < .01).

CONCLUSIONS

Cortical and spinal cord inputs are essential for regulation of postural control during standing with EO in SPMS. Without visual input, people with SPMS preferentially rely on somatosensory inputs from the spinal cord for maintaining postural control. Postural deficits related to cord atrophy over 2 years, suggesting that postural control may be a surrogate marker of disease progression in people with SPMS.

Orally Administered Alpha Lipoic Acid as a Treatment for Geographic Atrophy: A Randomized Clinical Trial

PURPOSE

Alpha lipoic acid (ALA) is a nutraceutical and potent antioxidant that has shown efficacy in the retina light damage mouse model and in humans for multiple sclerosis. Our objective was to evaluate the efficacy and safety of oral ALA for the treatment of geographic atrophy (GA).

DESIGN

Randomized, controlled, double-masked, multicenter phase 2 clinical trial of ALA versus placebo.

PARTICIPANTS

Participants with unilateral or bilateral GA from age-related macular degeneration.

METHODS

Participants were randomized to 1200 mg daily of ALA or placebo. Fundus autofluorescence, fundus color photography, and spectral-domain OCT were conducted and best-corrected visual acuity (BCVA) was obtained at baseline and every 6 months through month 18.

MAIN OUTCOME MEASURES

Annual rate of change over 18 months in square root-transformed area of GA in study eyes as measured on fundus autofluorescence. Secondary outcomes included the number of adverse events (AEs), change in BCVA, and annual rate of change in area of GA measured on color photographs.

RESULTS

Fifty-three participants (mean age, 80 years) were randomized (April 2016-August 2017). Twenty-seven participants (37 eyes) were in the placebo group, and 26 participants (36 eyes) were in the ALA group. Unadjusted mean (standard error) annual change in GA area was 0.28 (0.02) mm and 0.31 (0.02) mm for the placebo and ALA groups, respectively (difference, 0.04 mm; 95% confidence interval [CI], -0.03 to 0.11 mm; P = 0.30). Adjusting for baseline GA area, number of GA lesions, and presence of subfoveal GA, the mean annual change in GA area was 0.27 (0.04) mm and 0.32 (0.05) mm for the placebo and ALA groups, respectively (difference, 0.05 mm; 95% CI, -0.02 to 0.12 mm; P = 0.14). At 18 months, the percent of eyes losing 15 letters or more of BCVA was 22% (8 of 36) and 14% (5 of 36) in the placebo and ALA groups, respectively (P = 0.54). No difference was found in the percentage of participants with nonserious AEs (P = 0.96) or serious AEs (P = 0.28) between the placebo and ALA groups.

CONCLUSIONS

Results do not support ALA having beneficial effects on GA or BCVA. This trial design may be useful for other GA repurposing drug trials.

The Future of Progressive Multiple Sclerosis Therapies

INTRODUCTION

Multiple sclerosis (MS) affects more than a million people in the US. A considerable portion of these patients either begin with primary progressive disease or eventually transition to secondary progressive MS. A progressive disease course is the most critical factor affecting disability accumulation. The relatively recent development of treatments for relapsing multiple sclerosis has had a profound impact on the disease course for many with MS. Unfortunately, therapies for progressive MS have not had the same degree of advancement in general. New insights into the pathophysiology of progressive MS may lead to new treatments.

OBSERVATIONS

In this review, we identify some of the significant challenges encountered in the development of therapies for progressive MS, assess the evidence for use of currently approved therapies for patients with progressive MS, identify some of the current therapies in development from progressive MS, and consider the role for discontinuing therapy in certain patients.

CONCLUSIONS

Developing effective disease modifying therapies that slow or stop the gradual accumulation of neurologic disability in progressive MS represents a critical unmet need. As the understanding of the inflammatory and neurodegenerative aspects of MS are better elucidated there may be opportunity for advancement in the treatment of progressive MS.

Gastrointestinal Tolerability and Absorption of R- Versus R,S-Lipoic Acid in Progressive Multiple Sclerosis: A Randomized Crossover Trial

We compared the gastrointestinal (GI) tolerability and assessed for bioequivalent absorption of R-lipoic acid (LA) in people with progressive multiple sclerosis (MS) in a single-center, double-blind, randomized crossover trial. Participants randomly assigned to formulation sequence took 600 mg of R-LA or 1200 mg of a 1:1 racemic R,S-LA mixture in single daily doses for 7 to 10 days, underwent a washout of at least 7 days, and then took the other form of LA for 7 to 10 days. At the end of each period on LA, GI symptoms were assessed with GI questions from the Monitoring of Side Effects Scale. Serum LA concentrations were measured before and 60, 90, 120, 180, and 240 minutes after the first and last day's dose of each form of LA to derive an area under the plasma concentration-time curve (AUC) and maximum serum concentration (C_max ). Twenty participants enrolled (12 women; 15 secondary progressive MS, 5 primary progressive MS; mean age, 59.6 years). Two withdrew early due to symptoms while taking R,S-LA, and one withdrew early while taking R-LA. The mean GI Monitoring of Side Effects Scale score was 1.7 points lower on R-LA than on R,S-LA (P = .069), and there were fewer reports of each GI side effect when taking the R-LA than the R,S-LA (31 vs 60; P = .025). The AUC and C_max for R-LA were bioequivalent for the 2 formulations (90% confidence intervals 97.4% to 99.3% for AUC and 93.4% to 98.2% for C_max ). This study supports that in people with progressive MS, there is better GI tolerability and bioequivalent serum absorption of R-LA when 600 mg of R-LA is taken as R-LA alone than when taken in a 1:1 racemic R,S-LA mixture.

Efficacy of three neuroprotective drugs in secondary progressive multiple sclerosis (MS-SMART): a phase 2b, multiarm, double-blind, randomised placebo-controlled trial

Background

Neurodegeneration is the pathological substrate that causes major disability in secondary progressive multiple sclerosis. A synthesis of preclinical and clinical research identified three neuroprotective drugs acting on different axonal pathobiologies. We aimed to test the efficacy of these drugs in an efficient manner with respect to time, cost, and patient resource.

Methods

We did a phase 2b, multiarm, parallel group, double-blind, randomised placebo-controlled trial at 13 clinical neuroscience centres in the UK. We recruited patients (aged 25–65 years) with secondary progressive multiple sclerosis who were not on disease-modifying treatment and who had an Expanded Disability Status Scale (EDSS) score of 4·0–6·5. Participants were randomly assigned (1:1:1:1) at baseline, by a research nurse using a centralised web-based service, to receive twice-daily oral treatment of either amiloride 5 mg, fluoxetine 20 mg, riluzole 50 mg, or placebo for 96 weeks. The randomisation procedure included minimisation based on sex, age, EDSS score at randomisation, and trial site. Capsules were identical in appearance to achieve masking. Patients, investigators, and MRI readers were unaware of treatment allocation. The primary outcome measure was volumetric MRI percentage brain volume change (PBVC) from baseline to 96 weeks, analysed using multiple regression, adjusting for baseline normalised brain volume and minimisation criteria. The primary analysis was a complete-case analysis based on the intention-to-treat population (all patients with data at week 96). This trial is registered with ClinicalTrials.gov, NCT01910259.

Findings

Between Jan 29, 2015, and June 22, 2016, 445 patients were randomly allocated amiloride (n=111), fluoxetine (n=111), riluzole (n=111), or placebo (n=112). The primary analysis included 393 patients who were allocated amiloride (n=99), fluoxetine (n=96), riluzole (n=99), and placebo (n=99). No difference was noted between any active treatment and placebo in PBVC (amiloride vs placebo, 0·0% [95% CI −0·4 to 0·5; p=0·99]; fluoxetine vs placebo −0·1% [–0·5 to 0·3; p=0·86]; riluzole vs placebo −0·1% [–0·6 to 0·3; p=0·77]). No emergent safety issues were reported. The incidence of serious adverse events was low and similar across study groups (ten [9%] patients in the amiloride group, seven [6%] in the fluoxetine group, 12 [11%] in the riluzole group, and 13 [12%] in the placebo group). The most common serious adverse events were infections and infestations. Three patients died during the study, from causes judged unrelated to active treatment; one patient assigned amiloride died from metastatic lung cancer, one patient assigned riluzole died from ischaemic heart disease and coronary artery thrombosis, and one patient assigned fluoxetine had a sudden death (primary cause) with multiple sclerosis and obesity listed as secondary causes.

Interpretation

The absence of evidence for neuroprotection in this adequately powered trial indicates that exclusively targeting these aspects of axonal pathobiology in patients with secondary progressive multiple sclerosis is insufficient to mitigate neuroaxonal loss. These findings argue for investigation of different mechanistic targets and future consideration of combination treatment trials. This trial provides a template for future simultaneous testing of multiple disease-modifying medicines in neurological medicine.

Funding

Efficacy and Mechanism Evaluation (EME) Programme, an MRC and NIHR partnership, UK Multiple Sclerosis Society, and US National Multiple Sclerosis Society.

The effect of emerging nutraceutical interventions for clinical and biological outcomes in multiple sclerosis: A systematic review

BACKGROUND

Due to the considerable burden of multiple sclerosis (MS)-related symptoms and the need to identify effective interventions to prevent disease progression, various nutraceutical interventions have been trialed as adjunctive treatments. The aim of this review was to investigate the efficacy and safety of nutraceutical interventions for clinical and biological outcomes in people with MS.

METHODS

In accordance with PRISMA reporting guidelines, a systematic literature search was conducted using three electronic literature databases. Risk of bias was assessed using the Jadad scale.

RESULTS

Thirty-seven randomized controlled trials, investigating fourteen nutraceuticals, were included in the review. Trials that investigated alpha lipoic acid (n = 4/6), ginkgo biloba (n = 3/5), vitamin A (n = 2/2), biotin (n = 1/2), carnitine (n = 1/2), green tea (n = 1/2), coenzyme Q10 (n = 1/1), probiotics (n = 1/1), curcumin (n = 1/1), Andrographis paniculata (n = 1/1), ginseng (n = 1/1), and lemon verbena (n = 1/1) were reported to improve biological (e.g. MRI brain volume change, antioxidant capacity) and/or clinical (e.g. fatigue, depression, Expanded Disability Status Scale) outcomes in multiple sclerosis compared to control. However, most trials were relatively small (average study sample size across included studies, n = 55) and there were few replicate studies per nutraceutical to validate the reported results. Furthermore, some nutraceuticals (e.g. green tea and inosine) should be used with caution due to reported adverse events. Risk of bias across most studies was low, with 31 studies receiving a score between 4 and 5 (out of 5) on the Jadad Scale.

CONCLUSION

The existing literature provides preliminary support for the use of a number of nutraceutical interventions in MS. However, sufficiently powered long-term trials are required to expand the currently limited literature and to investigate unexplored nutraceuticals that may target relevant pathways involved in MS such as the gut microbiome and mitochondrial dysfunction. Prospero ID: CRD42018111736.

Are the beneficial effects of 'antioxidant' lipoic acid mediated through metabolism of reactive sulfur species?

The health benefits of lipoic acid (LA) are generally attributed to mitigating the harmful effects of reactive oxygen species (ROS). ROS are chemically similar to reactive sulfur species (RSS) and signal through identical mechanisms. Here we examined the effects of LA on RSS in HEK293 cells using H₂S and polysulfide (PS) specific fluorophores, AzMC and SSP4. We show that LA concentration-dependently increased both H₂S and PS. Physioxia (5% O₂) augmented the effects of LA on H₂S production but decreased PS production. Thiosulfate, a known substrate for reduced LA, and an intermediate in the catabolism of H₂S enhanced the effects of LA on H₂S and PS production. Inhibiting peroxiredoxins with conoidin A and gluraredoxins with tiopronin augmented the effects of LA on PS and H₂S, respectively while decreasing glutathione with buthionine-sulfoximine (BSO) or diethyl maleate (DEM) decreased the stimulatory effect of LA on H₂S production but augmented LA's effect on PS. Aminooxyacetate (AOA) and propargylglycine (PPG), inhibitors of H₂S production from cysteine partially inhibited LA augmentation of H₂S production and further decreased the LA effect when applied concurrently with BSO and DEM. The selective and cell-permeable H₂S scavenger, SS20, inhibited the effects of LA on cellular H₂S. Estimates of single-cell H₂S production suggest that 0.1-0.2% of O₂ consumption is used to metabolize H₂S and these requirements may increase to 1-2% with 1 mM LA. Collectively, these results suggest that LA rescues H₂S from irreversible oxidation and that the effects of LA on RSS directly confer antioxidant, anti-inflammatory and cytoprotective responses. They also suggest that TS may be an effective supplement to increase the efficacy of LA in clinical settings.

Mitochondrial Dysfunction and Alpha-Lipoic Acid: Beneficial or Harmful in Alzheimer's Disease?

Alzheimer's disease (AD) is a neurodegenerative disorder characterised by impairments in the cognitive domains associated with orientation, recording, and memory. This pathology results from an abnormal deposition of the β-amyloid (Aβ) peptide and the intracellular accumulation of neurofibrillary tangles. Mitochondrial dysfunctions play an important role in the pathogenesis of AD, due to disturbances in the bioenergetic properties of cells. To date, the usual therapeutic drugs are limited because of the diversity of cellular routes in AD and the toxic potential of these agents. In this context, alpha-lipoic acid (α-LA) is a well-known fatty acid used as a supplement in several health conditions and diseases, such as periphery neuropathies and neurodegenerative disorders. It is produced in several cell types, eukaryotes, and prokaryotes, showing antioxidant and anti-inflammatory properties. α-LA acts as an enzymatic cofactor able to regulate metabolism, energy production, and mitochondrial biogenesis. In addition, the antioxidant capacity of α-LA is associated with two thiol groups that can be oxidised or reduced, prevent excess free radical formation, and act on improvement of mitochondrial performance. Moreover, α-LA has mechanisms of epigenetic regulation in genes related to the expression of various inflammatory mediators, such PGE2, COX-2, iNOS, TNF-α, IL-1β, and IL-6. Regarding the pharmacokinetic profile, α-LA has rapid uptake and low bioavailability and the metabolism is primarily hepatic. However, α-LA has low risk in prolonged use, although its therapeutic potential, interactions with other substances, and adverse reactions have not been well established in clinical trials with populations at higher risk for diseases of aging. Thus, this review aimed to describe the pharmacokinetic profile, bioavailability, therapeutic efficacy, safety, and effects of combined use with centrally acting drugs, as well as report in vitro and in vivo studies that demonstrate the mitochondrial mechanisms of α-LA involved in AD protection.

Use of Vitamins and Dietary Supplements by Patients With Multiple Sclerosis: A Review

Importance

Surveys of patients with multiple sclerosis report that most are interested in modifying their diet and using supplements to potentially reduce the severity and symptoms of the disease. This review provides an updated overview of the current state of evidence for the role that vitamins and dietary supplements play in multiple sclerosis and its animal models, with an emphasis on recent studies, and addresses biological plausibility and safety issues.

Observations

Several vitamins and dietary supplements have been recently explored both in animal models and by patients with multiple sclerosis. Most human trials have been small or nonblinded, limiting their generalizability. Biotin and vitamin D are currently being tested in large randomized clinical trials. Smaller trials are ongoing or planned for other supplements such as lipoic acid and probiotics. The results of these studies may help guide clinical recommendations.

Conclusions and Relevance

At the present time, the only vitamin with sufficient evidence to support routine supplementation for patients with multiple sclerosis is vitamin D. Vitamin deficiencies should be avoided. It is important for clinicians to know which supplements their patients are taking and to educate patients on any known efficacy data, along with any potential medication interactions and adverse effects of individual supplements. Given that dietary supplements and vitamins are not subject to the same regulatory oversight as prescription pharmaceuticals in the United States, it is recommended that vitamins and supplements be purchased from reputable manufacturers with the United States Pharmacopeia designation.

Progressive multiple sclerosis: latest therapeutic developments and future directions

Multiple sclerosis (MS) is a chronic inflammatory condition of the central nervous system leading to demyelination and neurodegeneration. While the initial presentation is mostly characterized by a relapsing-remitting disease, patients often progress naturally after 10-15 years to a secondary-progressive disease course. Another 10-15% present with an initial, primary-progressive MS course. Pathogenic mechanisms possibly driving progression include continued compartmentalized inflammation by T- and B-lymphocytes and cells of innate immunity, oxidative stress, iron accumulation, and consecutive mitochondrial damage, altogether leading to neurodegeneration with accumulation of disability. Increasing knowledge about pathogenic mechanisms involved in progressive MS helps to design more specific and precise therapeutic approaches. Successful examples are the B-cell targeting monoclonal antibody ocrelizumab, effective in primary progressive MS, and the sphingosine-1-receptor modulator siponimod, effective in active forms of secondary-progressive MS. Apart from that, other medications such as the B-cell targeted antibody ofatumumab, cladribine due to T- and B-cell depletion, and other sphingosine-1-receptor modulators such as ozanimod and ponesimod are under development. Moreover, some therapeutic approaches in preclinical stages are under development. In this review, we will summarize the newest therapeutic development in the field of progressive MS of the last 3 years, and shed light on auspicious substances with similar mechanisms and new developments in the therapeutic pipeline, presumably supporting a bright future for progressive MS treatment.

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.

Cortical and meningeal pathology in progressive multiple sclerosis: a new therapeutic target?

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease that involves an intricate interaction between the central nervous system and the immune system. Nevertheless, its etiology is still unknown. MS exhibits different clinical courses: recurrent episodes with remission periods ('relapsing-remitting') that can evolve to a 'secondary progressive' form or persistent progression from the onset of the disease ('primary progressive'). The discovery of an effective treatment and cure has been hampered due to the pathological and clinical heterogeneity of the disease. Historically, MS has been considered as a disease exclusively of white matter. However, patients with progressive forms of MS present with cortical lesions associated with meningeal inflammation along with physical and cognitive disabilities. The pathogenesis of the cortical lesions has not yet been fully described. Animal models that represent both the cortical and meningeal pathologies will be critical in addressing MS pathogenesis as well as the design of specific treatments. In this review, we will address the state-of-the-art diagnostic and therapeutic alternatives and the development of strategies to discover new therapeutic approaches, especially for the progressive forms.

Progressive multiple sclerosis: from pathophysiology to therapeutic strategies

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that involves demyelination and axonal degeneration. Although substantial progress has been made in drug development for relapsing-remitting MS, treatment of the progressive forms of the disease, which are characterized clinically by the accumulation of disability in the absence of relapses, remains unsatisfactory. This unmet clinical need is related to the complexity of the pathophysiological mechanisms involved in MS progression. Chronic inflammation, which occurs behind a closed blood-brain barrier with activation of microglia and continued involvement of T cells and B cells, is a hallmark pathophysiological feature. Inflammation can enhance mitochondrial damage in neurons, which, consequently, develop an energy deficit, further reducing axonal health. The growth-inhibitory and inflammatory environment of lesions also impairs remyelination, a repair process that might protect axons from degeneration. Moreover, neurodegeneration is accelerated by the altered expression of ion channels on denuded axons. In this Review, we discuss the current understanding of these disease mechanisms and highlight emerging therapeutic strategies based on these insights, including those targeting the neuroinflammatory and degenerative aspects as well as remyelination-promoting approaches.

Diagnosis and Management of Progressive Multiple Sclerosis

Multiple sclerosis is a chronic autoimmune disease of the central nervous system that results in varying degrees of disability. Progressive multiple sclerosis, characterized by a steady increase in neurological disability independently of relapses, can occur from onset (primary progressive) or after a relapsing-remitting course (secondary progressive). As opposed to active inflammation seen in the relapsing-remitting phases of the disease, the gradual worsening of disability in progressive multiple sclerosis results from complex immune mechanisms and neurodegeneration. A few anti-inflammatory disease-modifying therapies with a modest but significant effect on measures of disease progression have been approved for the treatment of progressive multiple sclerosis. The treatment effect of anti-inflammatory agents is particularly observed in the subgroup of patients with younger age and evidence of disease activity. For this reason, a significant effort is underway to develop molecules with the potential to induce myelin repair or halt the degenerative process. Appropriate trial methodology and the development of clinically meaningful disability outcome measures along with imaging and biological biomarkers of progression have a significant impact on the ability to measure the efficacy of potential medications that may reverse disease progression. In this issue, we will review current evidence on the physiopathology, diagnosis, measurement of disability, and treatment of progressive multiple sclerosis.

Improving Outcomes in Pediatric Multiple Sclerosis: Current and Emerging Treatments

Pediatric-onset multiple sclerosis (MS) comprises 2-5% of MS cases, and is known to be associated with high disease activity and the accumulation of disability at an earlier age than their adult-onset counterparts. Appropriate therapy leading to disease control has the potential to alter the known trajectory of adverse long-term physical, cognitive, and psychosocial outcomes in this population. Thus, optimizing treatment for children and adolescents with MS is of paramount importance. The last decade has seen a growing number of disease-modifying therapies approved for relapsing MS in adults, and available agents now include oral, injectable, and infusion therapies. Recently, the development of randomized controlled MS trials in youth has led to the first agent approved by the US FDA for the treatment of pediatric MS-fingolimod. With this, we have entered a new era of knowledge and treatment in this population and ongoing pediatric trials are expected to further inform clinical management. With the emergence of highly effective therapies targeting the inflammatory component of the disease, there has been increased interest in identifying treatment strategies that instead target mechanisms such as remyelination/repair, neuroprotection, or rehabilitation. The potential role for such emerging therapies in the treatment of pediatric MS remains an important area of study. In this review, we discuss current evidence for MS therapies in children including the treatment of acute relapses, disease-modifying therapies, and symptomatic management. We will also discuss evidence for emerging therapies, including remyelinating and neuroprotective agents.

Effects of lipoic acid on primary murine microglial cells

The anti-oxidant lipoic acid (LA) is beneficial in murine models of multiple sclerosis (MS) and has recently been shown to slow brain atrophy in secondary progressive MS. The mechanism of these effects by LA is incompletely understood but may involve effects on microglia. The objective of this study is to understand how LA affects microglial cells. We cultured primary microglial cells from C57BL/6 adult mice brains and stimulated the cells with lipopolysaccharide (LPS) and interferon gamma (IFN-γ) in the presence or absence of LA. We demonstrate the inhibition of phagocytosis, rearrangement of actin, and formation of membrane blebs in stimulated microglia in the presence of LA. These experiments suggest that LA causes changes in microglial actin, which may lead to alterations in phagocytosis, mobility, and migration.

Oral lipoic acid as a treatment for acute optic neuritis: a blinded, placebo controlled randomized trial

Background

Lipoic acid, an antioxidant, has beneficial effects in experimental acute optic neuritis and autoimmune encephalomyelitis. Optical coherence tomography can detect retinal nerve fiber layer thinning, representing axonal degeneration, approximately 3–6 months after acute optic neuritis.

Objective

To determine whether lipoic acid is neuroprotective in acute optic neuritis.

Methods

A single-center, double-blind, randomized, placebo controlled, 24-week trial. Intervention included 6 weeks of once daily lipoic acid (1200 mg) or placebo within 14 days of acute optic neuritis diagnosis. The primary outcome was the mean difference in affected eye retinal nerve fiber layer (RNFL) thickness from baseline to 24 weeks.

Results

We enrolled 31 subjects (placebo n=16; lipoic acid n=15; average age 38.6 years (standard deviation (SD) 10.3)). Affected eye mean global RNFL thickness (µm) in the lipoic acid group decreased from 108.47 (SD 26.11) at baseline to 79.31 (SD 19.26) at 24 weeks. The affected eye RNFL in the placebo group decreased from 103.67 (SD 18.04) at baseline to 84.43 (SD 20.94) at 24 weeks. Unaffected eye RNFL thickness did not significantly change in either group over 24 weeks.

Conclusion

Six weeks of oral lipoic acid supplementation after acute optic neuritis is safe and well tolerated; however, because of insufficient recruitment, we could not conclude that lipoic acid treatment was neuroprotective in acute optic neuritis.

Mitochondrial Dysfunction and Multiple Sclerosis

In recent years, several studies have examined the potential associations between mitochondrial dysfunction and neurodegenerative diseases such as multiple sclerosis (MS), Parkinson’s disease and Alzheimer’s disease. In MS, neurological disability results from inflammation, demyelination, and ultimately, axonal damage within the central nervous system. The sustained inflammatory phase of the disease leads to ion channel changes and chronic oxidative stress. Several independent investigations have demonstrated mitochondrial respiratory chain deficiency in MS, as well as abnormalities in mitochondrial transport. These processes create an energy imbalance and contribute to a parallel process of progressive neurodegeneration and irreversible disability. The potential roles of mitochondria in neurodegeneration are reviewed. An overview of mitochondrial diseases that may overlap with MS are also discussed, as well as possible therapeutic targets for the treatment of MS and other neurodegenerative conditions.

Lipoic Acid and Other Antioxidants as Therapies for Multiple Sclerosis

Oxidative stress (OS), when oxidative forces outweigh endogenous and nutritional antioxidant defenses, contributes to the pathophysiology of multiple sclerosis (MS). Evidence of OS is found during acute relapses, in active inflammatory lesions, and in chronic, longstanding plaques. OS results in both ongoing inflammation and neurodegeneration. Antioxidant therapies are a rational strategy for people with MS with all phenotypes and disease durations. PURPOSE OF REVIEW: To understand the function of OS in health and disease, to examine the contributions of OS to MS pathophysiology, and to review current evidence for the effects of selected antioxidant therapies in people with MS (PwMS) with a focus on lipoic acid (LA). RECENT FINDINGS: Studies of antioxidant interventions in both animal and in vivo models result in reductions in serum markers of OS and increases in levels and activity of antioxidant enzymes. Antioxidant trials in PwMS, while generally underpowered, detect short-term improvements in markers of OS and antioxidant defenses, and to a lesser extent, in clinical symptoms (fatigue, depression). The best evidence to date is a 2-year trial of LA in secondary progressive MS which demonstrated a significant reduction of whole-brain atrophy and trend toward improvement in walking speed. Antioxidant therapy is a promising approach to treat MS across the spectrum and duration of disease. Rigorous and well-powered trials are needed to determine their therapeutic benefits.

Plant polyprenols reduce demyelination and recover impaired oligodendrogenesis and neurogenesis in the cuprizone murine model of multiple sclerosis

Recent studies showed hepatoprotective, neuroprotective, and immunomodulatory properties of polyprenols isolated from the green verdure of Picea abies (L.) Karst. This study aimed to investigate effects of polyprenols on oligodendrogenesis, neurogenesis, and myelin content in the cuprizone demyelination model. Demyelination was induced by 0.5% cuprizone in CD-1 mice during 10 weeks. Nine cuprizone-treated animals received daily injections of polyprenols intraperitoneally at a dose of 12-mg/kg body weight during Weeks 6-10. Nine control animals and other nine cuprizone-treated received sham oil injections. At Week 10, brain sections were stained for myelin basic protein, neuro-glial antigen-2, and doublecortin to evaluate demyelination, oligodendrogenesis, and neurogenesis. Cuprizone administration caused a decrease in myelin basic protein in the corpus callosum, cortex, hippocampus, and the caudate putamen compared with the controls. Oligodendrogenesis was increased, and neurogenesis in the subventricular zone and the dentate gyrus of the hippocampus was decreased in the cuprizone-treated group compared with the controls. Mice treated with cuprizone and polyprenols did not show significant demyelination and differences in oligodendrogenesis and neurogenesis as compared with the controls. Our results suggest that polyprenols can halt demyelination, restore impaired neurogenesis, and mitigate reactive overproduction of oligodendrocytes caused by cuprizone neurotoxicity.

Progesterone, Lipoic Acid, and Sulforaphane as Promising Antioxidants for Retinal Diseases: A Review

Oxidative stress has been documented to be a key factor in the cause and progression of different retinal diseases. Oxidative cellular unbalance triggers a sequence of reactions which prompt cell degeneration and retinal dysfunction, both hallmarks of several retinal pathologies. There is no effective treatment, yet, for many retinal diseases. Antioxidant treatment have been pointed out to be an encouraging palliative treatment; the beneficial effects documented involve slowing the progression of the disease, a reduction of cell degeneration, and improvement of retinal functions. There is a vast information corpus on antioxidant candidates. In this review, we expose three of the main antioxidant treatments, selected for their promising results that has been reported to date. Recently, the sulforaphane, an isothiocyanate molecule, has been unveiled as a neuroprotective candidate, by its antioxidant properties. Progesterone, a neurosteroid has been proposed to be a solid and effective neuroprotective agent. Finally, the lipoic acid, an organosulfur compound, is a well-recognized antioxidant. All of them, have been tested and studied on different retinal disease models. In this review, we summarized the published results of these works, to offer a general view of the current antioxidant treatment advances, including the main effects and mechanisms described.

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.

Ozanimod for the treatment of relapsing remitting multiple sclerosis

INTRODUCTION

Ozanimod is a selective sphingosine 1-phosphate receptor 1 and 5 modulator under development by Celgene, for the treatment of relapsing remitting multiple sclerosis. Extensive clinical experience has become available for the related compound fingolimod, favoring the sphingosine 1-phosphate therapeutic concept. Off-target effects have been attributed to its low receptor specificity and have prompted the development of next generation sphingosine 1-phosphate receptor modulators. Areas covered: The authors evaluate the literature of ozanimod, using the PubMed database as well as repositories of the European Committee for Treatment and Research in Multiple Sclerosis and the American and European Academy of Neurology. Specifically, the authors cover and discuss the preclinical data on ozanimod, pharmacokinetics and dynamics, and data on efficacy and safety from the pivotal trials. Expert opinion: Superiority of ozanimod over intramuscular interferon β-1a with regard to reduction in annualized relapse rate and magnetic resonance imaging outcomes has been shown in two phase III trials. The beneficial effect on brain volume and gray matter loss are encouraging and in line with data on other newer immunomodulators. Ozanimod is a valuable contribution to the therapeutic armamentarium in MS, although the effect on disability progression is unclear and requires further investigations.

Impact of trial design and patient heterogeneity on the identification of clinically effective therapies for progressive MS

Clinically effective immunomodulatory therapies have been developed for relapsing-remitting multiple sclerosis (RRMS), but they have generally not translated to a corresponding slowing of disability accumulation in progressive forms of multiple sclerosis (MS). Since disability is multifaceted, progressive patients are heterogeneous, and the drivers of disease progression are still unclear, it has been difficult to identify the most informative outcome measures for progressive trials. Historically, secondary outcome measures have focused on inflammatory measures, which contributed to the recent identification of immunomodulatory therapies benefiting younger patients with more inflammatory progressive MS. Meanwhile, agents capable of treating late-stage disease have remained elusive. Consequently, measures of neurodegeneration are becoming common. Here, we review completed clinical trials testing immunomodulatory therapies in primary progressive multiple sclerosis (PPMS) or secondary progressive multiple sclerosis (SPMS) and discuss the features contributing to trial design variability in relation to trial outcomes, and how efforts toward better patient stratification and inclusion of reliable progression markers could improve outcomes.

Effects of lipoic acid on walking performance, gait, and balance in secondary progressive multiple sclerosis

BACKGROUND

Gait and balance impairment is common in secondary progressive multiple sclerosis (SPMS). Lipoic acid (LA), an over-the-counter antioxidant, is effective in MS animal models and may improve walking speed, but effects on mobility are unreported.

OBJECTIVE

Examine the effects of 1200 mg daily oral dose of LA versus placebo (PLA) on gait and balance in a 2-year, randomized, double-blind pilot study.

METHODS

134 participants were screened for eligibility before assignment to LA (n = 28) or PLA (n = 26). Included here were, 21 participants with SPMS who took LA (N = 11) or PLA (N = 10) capsules for 2 years (enrolled May 2, 2011 - August 14, 2015) and completed all tasks without the use of an assistive device. Participants completed the Timed Up and Go (TUG) and quiet standing tasks every 6 months while wearing inertial sensors (APDM Opals) to quantify mobility.

RESULTS

LA had a medium effect on time to complete TUG at 2 years (g = 0.51; 95% CI = -0.35, 1.38). In a subset of 18 participants with less disability (EDSS < 6, no use of ambulatory device), turning time was significantly shorter with LA (p =  0.048, Δ= 0.48 s). No differences in balance metrics were found between groups.

CONCLUSIONS

LA had an effect on walking performance in people with SPMS, particularly in those with lower baseline disability.

TRIAL REGISTRATION

Lipoic Acid for Secondary Progressive Multiple Sclerosis https://clinicaltrials.gov/ct2/show/NCT01188811?term=spain+lipoic+acid&rank=1 NCT0118881.

Pharmacotherapy in Secondary Progressive Multiple Sclerosis: An Overview

Multiple sclerosis is an immune-mediated inflammatory disease of the central nervous system characterised by demyelination, neuroaxonal loss and a heterogeneous clinical course. Multiple sclerosis presents with different phenotypes, most commonly a relapsing-remitting course and, less frequently, a progressive accumulation of disability from disease onset (primary progressive multiple sclerosis). The majority of people with relapsing-remitting multiple sclerosis, after a variable time, switch to a stage characterised by gradual neurological worsening known as secondary progressive multiple sclerosis. We have a limited understanding of the mechanisms underlying multiple sclerosis, and it is believed that multiple genetic, environmental and endogenous factors are elements driving inflammation and ultimately neurodegeneration. Axonal loss and grey matter damage have been regarded as amongst the leading causes of irreversible neurological disability in the progressive stages. There are over a dozen disease-modifying therapies currently licenced for relapsing-remitting multiple sclerosis, but none of these has provided evidence of effectiveness in secondary progressive multiple sclerosis. Recently, there has been some early modest success with siponimod in secondary progressive multiple sclerosis and ocrelizumab in primary progressive multiple sclerosis. Finding treatments to delay or prevent the courses of secondary progressive multiple sclerosis is an unmet and essential goal of the research in multiple sclerosis. In this review, we discuss new findings regarding drugs with immunomodulatory, neuroprotective or regenerative properties and possible treatment strategies for secondary progressive multiple sclerosis. We examine the field broadly to include trials where participants have progressive or relapsing phenotypes. We summarise the most relevant results from newer investigations from phase II and III randomised controlled trials over the past decade, with particular attention to the last 5 years.

Early alpha-lipoic acid therapy protects from degeneration of the inner retinal layers and vision loss in an experimental autoimmune encephalomyelitis-optic neuritis model

Background

In multiple sclerosis (MS), neurodegeneration is the main reason for chronic disability. Alpha-lipoic acid (LA) is a naturally occurring antioxidant which has recently been demonstrated to reduce the rate of brain atrophy in progressive MS. However, it remains uncertain if it is also beneficial in the early, more inflammatory-driven phases. As clinical studies are costly and time consuming, optic neuritis (ON) is often used for investigating neuroprotective or regenerative therapeutics. We aimed to investigate the prospect for success of a clinical ON trial using an experimental autoimmune encephalomyelitis-optic neuritis (EAE-ON) model with visual system readouts adaptable to a clinical ON trial.

Methods

Using an in vitro cell culture model for endogenous oxidative stress, we compared the neuroprotective capacity of racemic LA with the R/S-enantiomers and its reduced form. In vivo, we analyzed retinal neurodegeneration using optical coherence tomography (OCT) and the visual function by optokinetic response (OKR) in MOG_35–55-induced EAE-ON in C57BL/6J mice. Ganglion cell counts, inflammation, and demyelination were assessed by immunohistological staining of retinae and optic nerves.

Results

All forms of LA provided equal neuroprotective capacities in vitro. In EAE-ON, prophylactic LA therapy attenuated the clinical EAE score and prevented the thinning of the inner retinal layer while therapeutic treatment was not protective on visual outcomes.

Conclusions

A prophylactic LA treatment is necessary to protect from visual loss and retinal thinning in EAE-ON, suggesting that a clinical ON trial starting therapy after the onset of symptoms may not be successful.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1111-y) contains supplementary material, which is available to authorized users.

Lipoic Acid Stimulates cAMP Production in Healthy Control and Secondary Progressive MS Subjects

Lipoic acid (LA) exhibits antioxidant and anti-inflammatory properties; supplementation reduces disease severity and T lymphocyte migration into the central nervous system in a murine model of multiple sclerosis (MS), and administration in secondary progressive MS (SPMS) subjects reduces brain atrophy compared to placebo. The mechanism of action (MOA) of LA's efficacy in suppression of MS pathology is incompletely understood. LA stimulates production of the immunomodulator cyclic AMP (cAMP) in vitro. To determine whether cAMP could be involved in the MOA of LA in vivo, we performed a clinical trial to examine whether LA stimulates cAMP production in healthy control and MS subjects, and whether there are differences in the bioavailability of LA between groups. We administered 1200 mg of oral LA to healthy control, relapsing remitting MS (RRMS) and SPMS subjects, and measured plasma LA and cAMP levels in peripheral blood mononuclear cells (PBMCs). There were no significant differences between the groups in pharmacokinetic (PK) parameters. Healthy and SPMS subjects had increased cAMP at 2 and 4 h post-LA treatment compared to baseline, while RRMS subjects showed decreases in cAMP. Additionally, plasma concentrations of prostaglandin E2 (PGE₂, a known cAMP stimulator) were significantly lower in female RRMS subjects compared to female HC and SPMS subjects 4 h after LA ingestion. These data indicate that cAMP could be part of the MOA of LA in SPMS, and that there is a divergent response to LA in RRMS subjects that may have implications in the efficacy of immunomodulatory drugs. This clinical trial, "Defining the Anti-inflammatory Role of Lipoic Acid in Multiple Sclerosis," NCT00997438, is registered at https://clinicaltrials.gov/ct2/show/record/NCT00997438 .