Real-world evidence of riluzole effectiveness in treating amyotrophic lateral sclerosis

Gene therapy breakthroughs in ALS: a beacon of hope for 20% of ALS patients

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease that remains incurable. Although the etiologies of ALS are diverse and the precise pathogenic mechanisms are not fully understood, approximately 20% of ALS cases are caused by genetic factors. Therefore, advancing targeted gene therapies holds significant promise, at least for the 20% of ALS patients with genetic etiologies. In this review, we summarize the main strategies and techniques of current ALS gene therapies based on ALS risk genes, and review recent findings from animal studies and clinical trials. Additionally, we highlight ALS-related genes with well-understood pathogenic mechanisms and the potential of numerous emerging gene-targeted therapeutic approaches for ALS.

Real-world evidence of riluzole on survival and ALSFRS change in a Chinese ALS cohort

AIMS

This study aimed to evaluate the effects of riluzole on survival and changes in ALS Functional Rating Scale (ALSFRS) among Chinese patients with Amyotrophic Lateral Sclerosis (ALS).

PATIENTS & METHODS

Propensity score matching was used to balance baseline variables between the riluzole group (n = 238) and control group (n = 454). Survival was analyzed using Kaplan - Meier curves and Cox regression, while multivariable linear regression assessed ALSFRS changes at 6 and 12 months. Subgroup analyses were conducted to identify potential responders.

RESULTS

Riluzole did not significantly improve survival (p = 0.478) or ALSFRS changes at 6 months (p = 0.380) or 12 months (p = 0.175). Subgroup analyses revealed no survival benefit in any subgroup, and further stratification showed inconsistent adverse effects on ALSFRS scores.

CONCLUSIONS

Riluzole neither prolonged survival nor slowed functional decline in Chinese ALS patients, with no subgroup demonstrating a better response.

Advances in the early diagnosis of amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disease. Despite rapid disease progression, diagnostic delay of 10-16 months persists, influenced by disease-specific factors and healthcare systems. Reducing it is crucial for early intervention, multidisciplinary care planning, and patient participation in clinical trials.

AREAS COVERED

The authors review relevant studies identified through PubMed from 1990 to 2024. The article explores factors contributing to diagnostic delay, the importance of early diagnosis, and strategies for improvement, including the role of diagnostic criteria and biomarkers.

EXPERT OPINION

Diagnosis of ALS remains clinical, with clinical expertise as the main modifiable factor in the diagnostic delay. Some biomarkers may be useful to speed up diagnosis at an earlier stage of the disease and in patients with atypical presentations or co-morbidities. However, the use of biomarkers for ALS diagnosis in clinical practice is far from being established and poses considerable challenges, including the lack of disease-specific biomarkers and the potential for delayed results. Until disease-specific biomarkers become available, early referral to ALS specialists, together with physician education programs, will remain the main tools to reduce diagnostic delay in the next years.

Novel Tissue-Specific Multifunctionalized Nanotechnological Platform Encapsulating Riluzole Against Motor Neuron Diseases

Background

Motor neuron diseases are neurological disorders characterized by progressive degeneration of upper and/or lower motor neurons. Amyotrophic Lateral Sclerosis (ALS) is the most common form of motor neuron diseases, where patients suffer progressive paralysis, muscle atrophy and finally death. Despite ALS severity, no treatment is safe and fully effective. In this area, Riluzole was the first drug approved and it constitutes the gold-standard for this pathology. However, to obtain suitable therapeutic efficacy, Riluzole requires high doses that are associated with severe adverse effects in other tissues. To attain Riluzole therapeutic efficacy avoiding other organs side-effects, new therapeutic strategies to enhance the delivery of Riluzole specifically to motor neurons constitute an unmet medical need. In this area, we have developed a novel multifunctional nanostructurated carrier to selectively deliver Riluzole to motor neurons.

Results

This work develops and characterizes at in vitro and in vivo levels a tissue-targeted formulation of peptide and PEG-labelled PLGA nanoparticles encapsulating Riluzole. For this purpose, pVEC, a cell penetrating peptide able to increase transport through the blood-brain barrier, was attached to the nanoparticles surface. The multifunctionalized nanoparticles show suitable characteristics for the release of Riluzole in the central nervous system and were detected in motor neurons within 1 h after administration while significantly reducing the concentration of Riluzole in non-therapeutic organs responsible of side effects.

Conclusion

A novel drug delivery system has been developed and characterized, demonstrating enhanced CNS biodistribution of riluzole, which shows promise as efficient therapeutic tool for motor neuron diseases, including amyotrophic lateral sclerosis.

Targeting common disease pathomechanisms to treat amyotrophic lateral sclerosis

The motor neuron disease amyotrophic lateral sclerosis (ALS) is a devastating condition with limited treatment options. The past few years have witnessed a ramping up of translational ALS research, offering the prospect of disease-modifying therapies. Although breakthroughs using gene-targeted approaches have shown potential to treat patients with specific disease-causing mutations, the applicability of such therapies remains restricted to a minority of individuals. Therapies targeting more general mechanisms that underlie motor neuron pathology in ALS are therefore of considerable interest. ALS pathology is associated with disruption to a complex array of key cellular pathways, including RNA processing, proteostasis, metabolism and inflammation. This Review details attempts to restore cellular homeostasis by targeting these pathways in order to develop effective, broadly-applicable ALS therapeutics.

Treatment continuity of amyotrophic lateral sclerosis with available riluzole formulations: state of the art and current challenges in a 'real-world' setting

Amyotrophic lateral sclerosis (ALS) is a rare multisystem neurodegenerative disease leading to death due to respiratory failure. Riluzole was the first disease modifying treatment approved in ALS. Randomized clinical trials showed a significant benefit of riluzole on survival in the months following randomization, with a good safety profile. 'Real-world' studies suggested that the survival benefit of riluzole is substantially greater, with an extended survival ranging between 6 and 19 months. The main limiting associated adverse effects of riluzole are non-severe gastrointestinal complications and an elevation of liver enzymes, observed in 10% of patients. While different classes of drugs have been approved in some countries, riluzole remains the gold standard of therapy. Dysphagia induced by ALS is a major challenge for food intake and riluzole administration. Tablet crushing is associated with a loss of drug intake and a risk of powder aspiration, which jeopardizes the benefits of riluzole. Riluzole oral suspension (ROS) and oral film (ROF) allow riluzole intake in patients with dysphagia. Both formulations are bioequivalent to riluzole tablets with a good safety profile albeit transient oral hypoaesthesia. In case of severe dysphagia, ROS can be used with percutaneous endoscopic gastrostomy. ROF, the last approved formulation, requires low swallowing capacities and may contribute to maintain the efficacy of riluzole when tablets are inadequate according to patient's status and/or preferences. To optimize treatment continuity in newly diagnosed patients, the expected psychological impact of formulation switching that may be perceived as the sign of disease progression should be anticipated.

Guidance for clinical management of pathogenic variant carriers at elevated genetic risk for ALS/FTD

There is a growing understanding of the presymptomatic stages of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) and nascent efforts aiming to prevent these devastating neurodegenerative diseases have emerged. This progress is attributable, in no small part, to the altruism of people living with pathogenic variants at elevated genetic risk for ALS/FTD via their willingness to participate in natural history studies and disease prevention trials. Increasingly, this community has also highlighted the urgent need to develop paradigms for providing appropriate clinical care for those at elevated risk for ALS and FTD. This manuscript summarises recommendations emanating from a multi-stakeholder Workshop (Malvern, Pennsylvania, 2023) that aimed to develop guidance for at-risk carriers and their treating physicians. Clinical care recommendations span genetic testing (including counselling and sociolegal implications); monitoring for the emergence of early motor, cognitive and behavioural signs of disease; and the use of Food and Drug Administration-approved small molecule drugs and gene-targeting therapies. Lifestyle recommendations focus on exercise, smoking, statin use, supplement use, caffeine intake and head trauma, as well as occupational and environmental exposures. While the evidence base to inform clinical and lifestyle recommendations is limited, this guidance document aims to appraise carriers and clinicians of the issues and best available evidence, and also to define the research agenda that could yield more evidence-informed guidelines.

Ancillary subunits KChIP2c and DPP6 differentially modulate the inhibition of Kv4.2 channels by riluzole

In native tissue, Kv4.2 channels associate with the ancillary subunits Kv channels interacting proteins (KChIPs) and dipeptidyl peptidase-related proteins (DPPs) to evoke rapidly activating/inactivating currents in the heart (Ito) and brain (IA). Despite extensive knowledge of Kv4.2 biophysical modulation by auxiliary subunits, the pharmacological effects, especially those related to the co-expressed subunit and the state-dependent drug binding, remain unknown. Here, we investigated the effects of co-expressing KChIP2c or DPP6 on the pharmacological inhibition of Kv4.2 channels by riluzole. Riluzole inhibited Kv4.2, Kv4.2/DPP6, and Kv4.2/KChIP2c channels in a voltage-independent manner, with potency ranked as Kv4.2/DPP6 > Kv4.2 > Kv4.2/KChIP2c. Additionally, to a dissimilar extent, riluzole inhibited the channels from the closed state, left-shifted the inactivation curves, and enhanced the closed-state inactivation (differently modifying the rate constants of this latter). More divergent effects were observed: the inactivation kinetics was accelerated in Kv4.2 and Kv4.2/KChIP2c but not in Kv4.2/DPP6; only in Kv4.2/KChIP2c, the activation curve was left-shifted and the recovery from inactivation was decelerated; and the closed-state inactivation developed faster in Kv4.2 and Kv4.2/DPP6 but was slower in Kv4.2/KChIP2c channels. Notably, inhibition from the closed-inactivated state was more rapid than from the closed state for the three channels. We conclude that riluzole can elicit differential effects on native Kv4.2 channels depending on the presence of distinct ancillary subunits. These findings contribute to our understanding of the interplay between auxiliary subunits and pharmacological regulation of α-subunits of ion channels, highlighting the role of the former by modulating the organ-specific effects of channel-interacting drugs.

Neuroglia in neurodegeneration: Amyotrophic lateral sclerosis and frontotemporal dementia

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are devastating neurodegenerative diseases sharing significant pathologic and genetic overlap, leading to consider these diseases as a continuum in the spectrum of their pathologic features. Although FTD compromises only specific brain districts, while ALS involves both the nervous system and the skeletal muscles, several neurocentric mechanisms are in common between ALS and FTD. Also, recent research has revealed the significant involvement of nonneuronal cells, particularly glial cells such as astrocytes, oligodendrocytes, microglia, and peripheral immune cells, in disease pathology. This chapter aims to provide an extensive overview of the current understanding of the role of glia in the onset and advancement of ALS and FTD, highlighting the recent implications in terms of prognosis and future treatment options.

Advances in Disease-Modifying Therapeutics for Chronic Neuromuscular Disorders

Neuromuscular disorders can cause respiratory impairment by affecting the muscle fibers, neuromuscular junction, or innervation of respiratory muscles, leading to significant morbidity and mortality. Over the past few years, new disease-modifying therapies have been developed and made available for treating different neuromuscular disorders. Some of these therapies have remarkable effectiveness, resulting in the prevention and reduction of respiratory complications. For myasthenia gravis (MG), efgartigimod, ravulizumab, rozanolixizumab, and zilucoplan have been Food and Drug Administration (FDA)-approved for the treatment of acetylcholine receptor (AChR) antibody-positive generalized MG in the past 2 years. Rozanolixiumab is also approved for treating MG caused by muscle-specific tyrosine kinase (MuSK) antibodies. The new MG therapeutics target the complement system or block the neonatal fragment crystallizable (Fc) receptors (FcRn), leading to significant clinical improvement. For spinal muscular atrophy (SMA), nusinersen (intrathecal route) and risdiplam (oral route) modify the splicing of the SMN2 gene, increasing the production of normal survival motor neuron (SMN) protein. Onasemnogene abeparvovec is a gene replacement therapy that encodes a functional SMN protein. All SMA medications, particularly onasemnogene abeparvovec, have led to clinically meaningful improvement. For late-onset Pompe disease (LOPD), avalglucosidase alfa has shown a greater improvement in respiratory function, ambulation, and functional outcomes in comparison to alglucosidase alfa, and cipaglucosidase alfa combined with miglustat has shown improvement in respiratory and motor function in a cohort of enzyme replacement therapy-experienced LOPD patients. Amyotrophic lateral sclerosis (ALS) remains a challenge. The two most recent FDA-approved medications, namely sodium phenylbutyrate and tofersen, may slow down the disease by a few months in a selected population but do not stop the progression of the disease.

Increase of HCN current in SOD1-associated amyotrophic lateral sclerosis

The clinical manifestations of sporadic amyotrophic lateral sclerosis (ALS) vary widely. However, the current classification of ALS is based mainly on clinical presentations, and the roles of electrophysiological and biomedical biomarkers remain limited. Herein, we investigated a group of patients with sporadic ALS and an ALS mouse model with superoxide dismutase 1 (SOD1)/G93A transgenes using nerve excitability tests (NETs) to investigate axonal membrane properties and chemical precipitation, followed by ELISA analysis to measure plasma misfolded protein levels. Six of 19 patients (31.6%) with sporadic ALS had elevated plasma misfolded SOD1 protein levels. In sporadic ALS patients, only those with elevated misfolded SOD1 protein levels showed an increased inward rectification in the current-voltage threshold curve and an increased threshold reduction in the hyperpolarizing threshold electrotonus in the NET study. Two familial ALS patients with SOD1 mutations also exhibited similar electrophysiological patterns of NET. For patients with sporadic ALS showing significantly increased inward rectification in the current-voltage threshold curve, we noted an elevation in plasma misfolded SOD1 level, but not in total SOD1, misfolded C9orf72 or misfolded phosphorylated TDP43 levels. Computer simulations demonstrated that the aforementioned axonal excitability changes are likely to be associated with an increase in hyperpolarization-activated cyclic nucleotide-gated (HCN) current. In SOD1/G93A mice, NET also showed an increased inward rectification in the current-voltage threshold curve, which could be reversed by a single injection of the HCN channel blocker, ZD7288. Daily treatment of SOD1/G93A mice with ZD7288 partly prevented the early motor function decline and spinal motor neuron death. In summary, sporadic ALS patients with elevated plasma misfolded SOD1 exhibited similar patterns of motor axonal excitability changes to familial ALS patients and ALS mice with mutant SOD1, suggesting the existence of SOD1-associated sporadic ALS. The observed NET pattern of increased inward rectification in the current-voltage threshold curve was attributable to an elevation in the HCN current in SOD1-associated ALS.

Pharmacological and non-pharmacological treatments in amyotrophic lateral sclerosis: an Italian real-world data study

BACKGROUND AND PURPOSE

The purpose was to describe the use patterns of pharmacological and non-pharmacological therapies and investigate potential determinants of riluzole use in patients newly diagnosed with amyotrophic lateral sclerosis (ALS) in three Italian regions.

METHODS

Amyotrophic lateral sclerosis patients were selected from administrative healthcare databases of Latium, Tuscany and Umbria from 1 January 2014 to 31 December 2019 based on hospital- and disease-specific co-payment exemption data. The first trace of ALS was considered the index date. Incident ALS cases were those without a trace of ALS during the 3-year look back. Patients were described in terms of demographics, clinical characteristics and drug use at baseline, and were classified into four categories based on riluzole use in the 2 years before and 1 year after the index date: prevalent, incident, former users and non-users. Use of symptomatic pharmacological and non-pharmacological therapies was described across these categories during 12 months after the index date. Determinants of riluzole use were also investigated.

RESULTS AND CONCLUSIONS

A total of 1636 ALS incident subjects were detected in the three regions, mainly aged 65-74 years. Patients were generally fragile with a high prevalence of comorbidities at baseline. Riluzole was used by 27.4% of the overall study cohort at baseline and steeply increased in the first year after the index date differently between regions (Latium 61.2%, Tuscany 85.0%, Umbria 76.5%), with about half of the subjects being incident users. In the 12 months after the index date, also symptomatic therapies increased, in riluzole users and non-users. Determinants analysis showed that higher patient severity and complexity were associated with a lower likelihood of being treated with riluzole.

Impairments of inhibitory neurons in amyotrophic lateral sclerosis and frontotemporal dementia

Amyotrophic lateral sclerosis and frontotemporal dementia are two fatal neurodegenerative disorders. They are part of a pathophysiological continuum, displaying clinical, neuropathological, and genetic overlaps. There is compelling evidence that neuronal circuit dysfunction is an early feature of both diseases. Impaired neuronal excitability, imbalanced excitatory and inhibitory influences, and altered functional connectivity have been reported. These phenomena are likely due to combined alterations in the various cellular components involved in the functioning of neuronal networks. This review focuses on one of these cellular components: inhibitory neurons. We assess the evidence for inhibitory neuron impairments in amyotrophic lateral sclerosis and frontotemporal dementia, as well as the mechanisms leading to the loss of inhibition. We also discuss the contributions of these alterations to symptoms, and the potential therapeutic strategies for targeting inhibitory neuron deficits.

Assessing the Effect of Riluzole on Motor Unit Discharge Properties

Background. This study aims to determine if Riluzole usage can change the function and excitability of motor neurons. Methods. The clinical data and indices of motor neuron excitability were assessed using high-density surface EMG parameters from 80 ALS participants. The persistent inward current was assessed using the discharge rate from paired motor units obtained from the tibialis anterior muscle. This enabled the discharge rate at recruitment, peak discharge rates and the hysteresis of the recruitment-derecruitment frequencies (also known as delta F) to be calculated. Limbs were classified according to their strength. Results. No differences in these motor neuron discharge properties were found according to whether Riluzole was used. Conclusions. The possible interpretations of this finding are discussed.

Exploratory study to evaluate the acceptability of a wearable accelerometer to assess motor progression in motor neuron disease

Motor neuron disease (MND) is a rapidly progressive condition traditionally assessed using a questionnaire to evaluate physical function, the revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R). Its use can be associated with poor sensitivity in detecting subtle changes over time and there is an urgent need for more sensitive and specific outcome measures. The ActiGraph GT9X is a wearable device containing multiple sensors that can be used to provide metrics that represent physical activity. The primary aim of this study was to investigate the initial suitability and acceptability of limb-worn wearable devices to group of people with MND in Scotland. A secondary aim was to explore the preliminary associations between the accelerometer sensor data within the ActiGraph GT9X and established measures of physical function. 10 participants with MND completed a 12-week schedule of assessments including fortnightly study visits, both in-person and over videoconferencing software. Participants wore the device on their right wrist and right ankle for a series of movements, during a 6-min walking test and for a period of 24-h wear, including overnight. Participants also completed an ALSFRS-R and questionnaires on their experience with the devices. 80% of the participants found wearing these devices to be a positive experience and no one reported interference with daily living or added burden. However, 30% of the participants experienced technical issues with their devices. Data from the wearable devices correlated with established measures of physical function.

Edaravone for the Treatment of Motor Neurone Disease: A Critical Review of Approved and Alternative Formulations against a Proposed Quality Target Product Profile

Edaravone is one of two main drugs for treating motor neurone disease (MND). This review proposes a specific quality target product profile (QTPP) for edaravone following an appraisal of the issues accounting for the poor clinical uptake of the approved IV and oral liquid edaravone formulations. This is followed by a review of the alternative oral formulations of edaravone described in the published patent and journal literature against the QTPP. A total of 14 texts published by six research groups on 18 novel oral formulations of edaravone for the treatment of MND have been reviewed. The alternative oral formulations included liquid and solid formulations developed with cyclodextrins, lipids, surfactants, co-surfactants, alkalising agents, tablet excipients, and co-solvents. Most were intended to deliver edaravone for drug absorption in the lower gastrointestinal tract (GIT); however, there were also four formulations targeting the oral mucosal absorption of edaravone to avoid first-pass metabolism. All the novel formulations improved the aqueous solubility, stability, and oral bioavailability (BA) of edaravone compared to an aqueous suspension of edaravone. A common limitation of the published formulations is the lack of MND-patient-centred data. Except for TW001, no other formulations have been trialled in MND patients. To meet the QTPP of an oral edaravone formulation for MND patients, it is recommended that a tablet of appropriate size and with acceptable taste and stability be designed for the effective sublingual or buccal absorption of edaravone. This tablet should be designed with input from the MND community.

Sodium Phenylbutyrate and Tauroursodeoxycholic Acid: A Story of Hope Turned to Disappointment in Amyotrophic Lateral Sclerosis Treatment

The absence of a definitive cure for amyotrophic lateral sclerosis (ALS) emphasizes the crucial need to explore new and improved treatment approaches for this fatal, progressive, and disabling neurodegenerative disorder. As at the end of 2023, five treatments - riluzole, edaravone, dextromethorphan hydrobromide + quinidine sulfate (DHQ), tofersen, and sodium phenylbutyrate-tauroursodeoxycholic acid (PB-TUDCA) - were FDA approved for the treatment of patients with ALS. Among them PB-TUDCA has been shown to impact DNA processing impairments, mitochondria dysfunction, endoplasmic reticulum stress, oxidative stress, and pathologic folded protein agglomeration defects, which have been associated with ALS pathophysiology. The Phase 2 CENTAUR trial demonstrated significant impact of PB-TUDCA on the ALS Functional Rating Scale-Revised (ALSFRS-R) risk of death, hospitalization, and the need for tracheostomy or permanent assisted ventilation in patients with ALS based on post hoc analyses. More recently, contrasting with the CENTAUR trial results, results from the Phase 3 PHOENIX trial (NCT05021536) showed no change in ALSFRS-R total score at 48 weeks. Consequently, the sponsor company initiated the process with the US FDA and Health Canada to voluntarily withdraw the marketing authorizations for PB-TUDCA. In the present article, we review ALS pathophysiology, with a focus on PB-TUDCA's proposed mechanisms of action and recent clinical trial results and discuss the implications of conflicting trial data for ALS and other neurological disorders.

The role of statins in amyotrophic lateral sclerosis: protective or not?

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of motor neurons characterized by muscle weakness, muscle twitching, and muscle wasting. ALS is regarded as the third-most frequent neurodegenerative disease, subsequent to Alzheimer's disease (AD) and Parkinson's disease (PD). The World Health Organization (WHO) in 2007 declared that prolonged use of statins may induce development of ALS-like syndrome and may increase ALS risk. Subsequently, different studies have implicated statins in the pathogenesis of ALS. In contrast, results from preclinical and clinical studies highlighted the protective role of statins against ALS neuropathology. Recently, meta-analyses and systematic reviews illustrated no association between long-term use of statins and ALS risk. These findings highlighted controversial points regarding the effects of statins on ALS pathogenesis and risk. The neuroprotective effects of statins against the development and progression of ALS may be mediated by regulating dyslipidemia and inflammatory changes. However, the mechanism for induction of ALS neuropathology by statins may be related to the dysregulation of liver X receptor signaling (LXR) signaling in the motor neurons and reduction of cholesterol, which has a neuroprotective effect against ALS neuropathology. Nevertheless, the exact role of statins on the pathogenesis of ALS was not fully elucidated. Therefore, this narrative review aims to discuss the role of statins in ALS neuropathology.

Profiling tofersen as a treatment of superoxide dismutase 1 amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive motor neuron disorder with a fatal outcome 3-5 years after disease onset due to respiratory complications. Superoxide dismutase 1 (SOD1) mutations are found in about 2% of all patients. Tofersen is a novel oligonucleotide antisense drug specifically developed to treat SOD1-ALS patients.

AREAS COVERED

Our review covers and discusses tofersen pharmacological properties and its phase I/II and III clinical trials results. Other available drugs and their limitations are also addressed.

EXPERT OPINION

VALOR study failed to meet the primary endpoint (change in the revised Amyotrophic Lateral Sclerosis Functional Rating Scale score from baseline to week 28, tofersen arm vs. placebo), but a significant reduction in plasma neurofilament light chain (NfL) levels was observed in tofersen arm (60% vs. 20%). PrefALS study has proposed plasma NfL has a potential biomarker for presymptomatic treatment, since it increases 6-12 months before phenoconversion. There is probably a delay between plasma NfL reduction and the clinical benefit. ATLAS study will allow more insights regarding tofersen clinical efficacy in disease progression rate, survival, and even disease onset delay in presymptomatic SOD1 carriers.

Chronological and Biological Aging in Amyotrophic Lateral Sclerosis and the Potential of Senolytic Therapies

Amyotrophic Lateral Sclerosis (ALS) is a group of sporadic and genetic neurodegenerative disorders that result in losses of upper and lower motor neurons. Treatment of ALS is limited, and survival is 2-5 years after disease onset. While ALS can occur in younger individuals, the risk significantly increases with advancing age. Notably, both sporadic and genetic forms of ALS share pathophysiological features overlapping hallmarks of aging including genome instability/DNA damage, mitochondrial dysfunction, inflammation, proteostasis, and cellular senescence. This review explores chronological and biological aging in the context of ALS onset and progression. Age-related muscle weakness and motor unit loss mirror aspects of ALS pathology and coincide with peak ALS incidence, suggesting a potential link between aging and disease development. Hallmarks of biological aging, including DNA damage, mitochondrial dysfunction, and cellular senescence, are implicated in both aging and ALS, offering insights into shared mechanisms underlying disease pathogenesis. Furthermore, senescence-associated secretory phenotype and senolytic treatments emerge as promising avenues for ALS intervention, with the potential to mitigate neuroinflammation and modify disease progression.

Protein aggregation and therapeutic strategies in SOD1- and TDP-43- linked ALS

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with severe socio-economic impact. A hallmark of ALS pathology is the presence of aberrant cytoplasmic inclusions composed of misfolded and aggregated proteins, including both wild-type and mutant forms. This review highlights the critical role of misfolded protein species in ALS pathogenesis, particularly focusing on Cu/Zn superoxide dismutase (SOD1) and TAR DNA-binding protein 43 (TDP-43), and emphasizes the urgent need for innovative therapeutic strategies targeting these misfolded proteins directly. Despite significant advancements in understanding ALS mechanisms, the disease remains incurable, with current treatments offering limited clinical benefits. Through a comprehensive analysis, the review focuses on the direct modulation of the misfolded proteins and presents recent discoveries in small molecules and peptides that inhibit SOD1 and TDP-43 aggregation, underscoring their potential as effective treatments to modify disease progression and improve clinical outcomes.

Current neuroprotective therapies and future prospects for motor neuron disease

Four medications with neuroprotective disease-modifying effects are now in use for motor neuron disease (MND). With FDA approvals for tofersen, relyvrio and edaravone in just the past year, 2022 ended a quarter of a century when riluzole was the sole such drug to offer to patients. The acceleration of approvals may mean we are witnessing the beginning of a step-change in how MND can be treated. Improvements in understanding underlying disease biology has led to more therapies being developed to target specific and multiple disease mechanisms. Consideration for how the pipeline of new therapeutic agents coming through in clinical and preclinical development can be more effectively evaluated with biomarkers, advances in patient stratification and clinical trial design pave the way for more successful translation for this archetypal complex neurodegenerative disease. While it must be cautioned that only slowed rates of progression have so far been demonstrated, pre-empting rapid neurodegeneration by using neurofilament biomarkers to signal when to treat, as is currently being trialled with tofersen, may be more effective for patients with known genetic predisposition to MND. Early intervention with personalized medicines could mean that for some patients at least, in future we may be able to substantially treat what is considered by many to be one of the most distressing diseases in medicine.

Amyotrophic lateral sclerosis: exploring pathophysiology in the context of treatment

Amyotrophic lateral sclerosis (ALS) is a complex, neurodegenerative disorder in which alterations in structural, physiological, and metabolic parameters act synergistically. Over the last decade there has been a considerable focus on developing drugs to slow the progression of the disease. Despite this, only four disease-modifying therapies are approved in North America. Although additional research is required for a thorough understanding of ALS, we have accumulated a large amount of knowledge that could be better integrated into future clinical trials to accelerate drug development and provide patients with improved treatment options. It is likely that future, successful ALS treatments will take a multi-pronged therapeutic approach, targeting different pathways, akin to personalized medicine in oncology. In this review, we discuss the link between ALS pathophysiology and treatments, looking at the therapeutic failures as learning opportunities that can help us refine and optimize drug development.

Knockdown of tgfb1a partially improves ALS phenotype in a transient zebrafish model

Amyotrophic lateral sclerosis (ALS) corresponds to a neurodegenerative disorder marked by the progressive degeneration of both upper and lower motor neurons located in the brain, brainstem, and spinal cord. ALS can be broadly categorized into two main types: sporadic ALS (sALS), which constitutes approximately 90% of all cases, and familial ALS (fALS), which represents the remaining 10% of cases. Transforming growth factor type-β (TGF-β) is a cytokine involved in various cellular processes and pathological contexts, including inflammation and fibrosis. Elevated levels of TGF-β have been observed in the plasma and cerebrospinal fluid (CSF) of both ALS patients and mouse models. In this perspective, we explore the impact of the TGF-β signaling pathway using a transient zebrafish model for ALS. Our findings reveal that the knockdown of tgfb1a lead to a partial prevention of motor axon abnormalities and locomotor deficits in a transient ALS zebrafish model at 48 h post-fertilization (hpf). In this context, we delve into the proposed distinct roles of TGF-β in the progression of ALS. Indeed, some evidence suggests a dual role for TGF-β in ALS progression. Initially, it seems to exert a neuroprotective effect in the early stages, but paradoxically, it may contribute to disease progression in later stages. Consequently, we suggest that the TGF-β signaling pathway emerges as an attractive therapeutic target for treating ALS. Nevertheless, further research is crucial to comprehensively understand the nuanced role of TGF-β in the pathological context.

Current perspectives on neuromodulation in ALS patients: A systematic review and meta-analysis

Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease that affects motor neurons, resulting in muscle weakness, paralysis, and eventually patient mortality. In recent years, neuromodulation techniques have emerged as promising potential therapeutic approaches to slow disease progression and improve the quality of life of ALS patients. A systematic review was conducted until August 8, 2023, to evaluate the neuromodulation methods used and their potential in the treatment of ALS. The search strategy was applied in the Cochrane Central database, incorporating results from other databases such as PubMed, Embase, CTgov, CINAHL, and ICTRP. Following the exclusion of papers that did not fulfil the inclusion criteria, a total of 2090 records were found, leaving a total of 10 studies. R software was used to conduct meta-analyses based on the effect sizes between the experimental and control groups. This revealed differences in muscle stretch measures with manual muscle testing (p = 0.012) and resting motor threshold (p = 0.0457), but not with voluntary isometric contraction (p = 0.1883). The functionality of ALS was also different (p = 0.007), but not the quality of life. Although intracortical facilitation was not seen in motor cortex 1 (M1) (p = 0.1338), short-interval intracortical inhibition of M1 was significant (p = 0.0001). BDNF showed no differences that were statistically significant (p = 0.2297). Neuromodulation-based treatments are proposed as a promising therapeutic approach for ALS that can produce effects on muscle function, spasticity, and intracortical connections through electrical, magnetic, and photonic stimulation. Photobiomodulation stands out as an innovative approach that uses specific wavelengths to influence mitochondria, with the aim of improving mitochondrial function and reducing excitotoxicity. The lack of reliable placebo controls and the variation in stimulation frequency are some of the drawbacks of neuromodulation.

Heterogeneous treatment effect estimation for observational data using model-based forests

The estimation of heterogeneous treatment effects has attracted considerable interest in many disciplines, most prominently in medicine and economics. Contemporary research has so far primarily focused on continuous and binary responses where heterogeneous treatment effects are traditionally estimated by a linear model, which allows the estimation of constant or heterogeneous effects even under certain model misspecifications. More complex models for survival, count, or ordinal outcomes require stricter assumptions to reliably estimate the treatment effect. Most importantly, the noncollapsibility issue necessitates the joint estimation of treatment and prognostic effects. Model-based forests allow simultaneous estimation of covariate-dependent treatment and prognostic effects, but only for randomized trials. In this paper, we propose modifications to model-based forests to address the confounding issue in observational data. In particular, we evaluate an orthogonalization strategy originally proposed by Robinson (1988, Econometrica) in the context of model-based forests targeting heterogeneous treatment effect estimation in generalized linear models and transformation models. We found that this strategy reduces confounding effects in a simulated study with various outcome distributions. We demonstrate the practical aspects of heterogeneous treatment effect estimation for survival and ordinal outcomes by an assessment of the potentially heterogeneous effect of Riluzole on the progress of Amyotrophic Lateral Sclerosis.

Analyzing the ER stress response in ALS patient derived motor neurons identifies druggable neuroprotective targets

Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron (MN) disease with severely limited treatment options. Identification of effective treatments has been limited in part by the lack of predictive animal models for complex human disorders. Here, we utilized pharmacologic ER stressors to exacerbate underlying sensitivities conferred by ALS patient genetics in induced pluripotent stem cell (iPSC)-derived motor neurons (MNs). In doing so, we found that thapsigargin and tunicamycin exposure recapitulated ALS-associated degeneration, and that we could rescue this degeneration via MAP4K4 inhibition (MAP4K4i). We subsequently identified mechanisms underlying MAP4K4i-mediated protection by performing phosphoproteomics on iPSC-derived MNs treated with ER stressors ±MAP4K4i. Through these analyses, we found JNK, PKC, and BRAF to be differentially modulated in MAP4K4i-protected MNs, and that inhibitors to these proteins could also rescue MN toxicity. Collectively, this study highlights the value of utilizing ER stressors in ALS patient MNs to identify novel druggable targets.

Fecal microbiota transplantation significantly improved respiratory failure of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that leads to respiratory failure, and eventually death. However, there is a lack of effective treatments for ALS. Here we report the results of fecal microbiota transplantation (FMT) in two patients with late-onset classic ALS with a Japan ALS severity classification of grade 5 who required tracheostomy and mechanical ventilation. In both patients, significant improvements in respiratory function were observed following two rounds of FMT, leading to weaning off mechanical ventilation. Their muscle strength improved, allowing for assisted standing and mobility. Other notable treatment responses included improved swallowing function and reduced muscle fasciculations. Metagenomic and metabolomic analysis revealed an increase in beneficial Bacteroides species (Bacteroides stercoris, Bacteroides uniformis, Bacteroides vulgatus), and Faecalibacterium prausnitzii after FMT, as well as elevated levels of metabolites involved in arginine biosynthesis and decreased levels of metabolites involved in branched-chain amino acid biosynthesis. These findings offer a potential rescue therapy for ALS with respiratory failure and provide new insights into ALS in general.

The preferences of people with amyotrophic lateral sclerosis on riluzole treatment in Europe

The Patient Preference Survey aims to understand unmet needs related to riluzole management in people with Amyotrophic Lateral Sclerosis (ALS) and to identify which characteristics of a new formulation could better match their preferences. The survey involved 117 people with ALS (PALS) treated with riluzole in four European countries. The dysphagic PALS were least satisfied with the riluzole tablet and oral suspension and with ease in self-administration; up to 68% of respondents postponed or missed the treatment due to swallowing difficulties and need of caregiver assistance. Overall, 51% of tablet and 53% of oral suspension users regularly crushed or mixed riluzole with beverages, respectively; PALS who always manipulated riluzole showed low satisfaction with the formulation and considered the risk of choking and pneumonia the most worrisome event. The survey evaluated the driving factors in choosing/switching the therapy: 67% of PALS declared a low risk of choking. The research finally evaluated which attributes of a new formulation would be preferred: the most relevant were ease of use (4.3/5), convenient/portable packaging (4.0/5) and oral-dissolving properties without tongue motility (3.9/5). The Patient Preference Survey suggests that patients have several unmet needs and preferences that could be addressed by a different formulation, e.g. using oral film technologies.

Add-on treatment with Cerebrolysin improves clinical symptoms in patients with ALS: results from a prospective, single-center, placebo-controlled, randomized, double-blind, phase II study

Amyotrophic lateral sclerosis (ALS) is a devastating and progressive neurodegenerative disease with limited treatment options available. Cerebrolysin is a drug candidate for the treatment of ALS because of its neuroprotective and neuroregenerative effects. We initiated a pilot clinical study of a combination of Cerebrolysin and riluzole to assess the therapeutic benefit of Cerebrolysin as an add-on treatment on clinical signs and symptoms in outpatients with ALS. Twenty patients with a clinically definitive diagnosis of ALS were enrolled and randomly assigned in a 1:1 ratio to receive Cerebrolysin or placebo. All patients received 50 mg of riluzole PO twice daily as a standard treatment. Patients in the Cerebrolysin group received intravenous injections of 10 mL of Cerebrolysin once daily, five days a week for the first month and three days a week for the next two months. Analysis of the ALS Functional Rating Scale - revised at Month 1 (primary outcome measure), showed a significant treatment effect in favor of Cerebrolysin with a 2.3-point improvement from baseline to Month 1 compared to a 0.9-point decrease in patients on placebo (P=0.005). The effect was maintained over the three-month study period, and the beneficial effect of Cerebrolysin over placebo was also evident in the secondary outcome measures. The safety analysis showed that the combination of riluzole and Cerebrolyisn was well tolerated. Our results demonstrate for the first time a significant clinical effect of Cerebrolysin in improving functional outcomes in patients with ALS and suggest that Cerebrolysin has potential as a novel therapeutic option for ALS.

Therapeutic targeting of ALS pathways: Refocusing an incomplete picture

Numerous potential amyotrophic lateral sclerosis (ALS)-relevant pathways have been hypothesized and studied preclinically, with subsequent translation to clinical trial. However, few successes have been observed with only modest effects. Along with an improved but incomplete understanding of ALS as a neurodegenerative disease is the evolution of more sophisticated and diverse in vitro and in vivo preclinical modeling platforms, as well as clinical trial designs. We highlight proposed pathological pathways that have been major therapeutic targets for investigational compounds. It is likely that the failures of so many of these therapeutic compounds may not have occurred because of lack of efficacy but rather because of a lack of preclinical modeling that would help define an appropriate disease pathway, as well as a failure to establish target engagement. These challenges are compounded by shortcomings in clinical trial design, including lack of biomarkers that could predict clinical success and studies that are underpowered. Although research investments have provided abundant insights into new ALS-relevant pathways, most have not yet been developed more fully to result in clinical study. In this review, we detail some of the important, well-established pathways, the therapeutics targeting them, and the subsequent clinical design. With an understanding of some of the shortcomings in translational efforts over the last three decades of ALS investigation, we propose that scientists and clinicians may choose to revisit some of these therapeutic pathways reviewed here with an eye toward improving preclinical modeling, biomarker development, and the investment in more sophisticated clinical trial designs.

Janus kinase inhibitors are potential therapeutics for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a poorly treated multifactorial neurodegenerative disease associated with multiple cell types and subcellular organelles. As with other multifactorial diseases, it is likely that drugs will need to target multiple disease processes and cell types to be effective. We review here the role of Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) signalling in ALS, confirm the association of this signalling with fundamental ALS disease processes using the BenevolentAI Knowledge Graph, and demonstrate that inhibitors of this pathway could reduce the ALS pathophysiology in neurons, glia, muscle fibres, and blood cells. Specifically, we suggest that inhibition of the JAK enzymes by approved inhibitors known as Jakinibs could reduce STAT3 activation and modify the progress of this disease. Analysis of the Jakinibs highlights baricitinib as a suitable candidate due to its ability to penetrate the central nervous system and exert beneficial effects on the immune system. Therefore, we recommend that this drug be tested in appropriately designed clinical trials for ALS.

Amyotrophic Lateral Sclerosis and Other Motor Neuron Diseases

OBJECTIVE

This article reviews the clinical spectrum of amyotrophic lateral sclerosis (ALS), its variant presentations, and the approach to diagnosis and management. This review includes a detailed discussion of current and emerging disease-modifying therapies and the management of respiratory and bulbar manifestations of disease. An updated review of ALS genetics and pathophysiology is also provided. This article also touches on several other important motor neuron diseases.

LATEST DEVELOPMENTS

A new set of simplified diagnostic criteria may help identify patients at earlier stages of the disease. A coformulation of sodium phenylbutyrate and tauroursodeoxycholic acid has been shown to have a significant benefit on disease progression and survival, leading to approval by regulatory authorities in the United States and Canada. An oral formulation of edaravone and an antisense oligonucleotide to a SOD1 gene variation (tofersen) have also recently been approved by the US Food and Drug Administration (FDA). Phase 3 trials of intrathecal mesenchymal stem cells failed to meet primary end points for efficacy. Updated American Academy of Neurology quality measures for the care of patients with ALS were published in 2023.

ESSENTIAL POINTS

There has been continued progress in ALS genetics, diagnosis, and disease-modifying therapies. However, we still lack a definitive biomarker or a treatment that can halt the progression or reverse the course of disease. The evolving understanding of the genetic and pathophysiologic underpinnings of disease offers promise for more effective and clinically meaningful treatments in the future.

Healthcare resource utilization at different stages of amyotrophic lateral sclerosis: Results from a real-world survey

People with amyotrophic lateral sclerosis (pALS) require complex, multi-disciplinary care, resulting in extensive healthcare resource utilization (HCRU). To investigate the relationship between HCRU and ALS progression, the study objectives were (i) to characterize HCRU in pALS and (ii) to establish whether this varied according to disease stage, as defined using three different methodologies: neurologist-defined early/mid/late stage, the King's clinical staging system for ALS, and the Milan Torino Staging system for ALS (MiToS). Real-world data were drawn from the Adelphi ALS Disease-Specific Programme™, a point-in-time survey of neurologists in France, Germany, Italy, Spain, the UK, and the USA conducted July 2020-March 2021. The analysis included survey responses from 142 physicians with respect to 880 pALS. With advancing ALS stage, significant differences were observed in the number of healthcare professional consultations and X-rays per person (both p < 0.05 for all staging systems), and the proportion of pALS with emergency room admissions, intensive care unit admissions, and assisted ventilation (all p < 0.05 for all staging systems). Across stages, >55% of pALS received care from a general neurologist and a general/primary care practitioner. With increasing stage, there was a significant difference in the proportion receiving care from a physical therapist, pulmonologist/respiratory care practitioner, respiratory therapist, speech/language therapist, and palliative care team, and in the proportion receiving care only from professional caregivers (all p < 0.05 for all staging systems). This study confirmed the substantial HCRU required to support pALS through all stages of ALS and highlighted an increasing need for healthcare resources as the disease progresses.

CRISPR interference to evaluate modifiers of C9ORF72-mediated toxicity in FTD

Treatments for neurodegenerative disease, including Frontotemporal dementia (FTD) and Amyotrophic lateral sclerosis (ALS), remain rather limited, underscoring the need for greater mechanistic insight and disease-relevant models. Our ability to develop novel disease models of genetic risk factors, disease modifiers, and other FTD/ALS-relevant targets is impeded by the significant amount of time and capital required to develop conventional knockout and transgenic mice. To overcome these limitations, we have generated a novel CRISPRi interference (CRISPRi) knockin mouse. CRISPRi uses a catalytically dead form of Cas9, fused to a transcriptional repressor to knockdown protein expression, following the introduction of single guide RNA against the gene of interest. To validate the utility of this model we have selected the TAR DNA binding protein (TDP-43) splicing target, stathmin-2 (STMN2). STMN2 RNA is downregulated in FTD/ALS due to loss of TDP-43 activity and STMN2 loss is suggested to play a role in ALS pathogenesis. The involvement of STMN2 loss of function in FTD has yet to be determined. We find that STMN2 protein levels in familial FTD cases are significantly reduced compared to controls, supporting that STMN2 depletion may be involved in the pathogenesis of FTD. Here, we provide proof-of-concept that we can simultaneously knock down Stmn2 and express the expanded repeat in the Chromosome 9 open reading frame 72 (C9ORF72) gene, successfully replicating features of C9-associated pathology. Of interest, depletion of Stmn2 had no effect on expression or deposition of dipeptide repeat proteins (DPRs), but significantly decreased the number of phosphorylated Tdp-43 (pTdp-43) inclusions. We submit that our novel CRISPRi mouse provides a versatile and rapid method to silence gene expression in vivo and propose this model will be useful to understand gene function in isolation or in the context of other neurodegenerative disease models.

An In Vivo Electroencephalographic Analysis of the Effect of Riluzole against Limbic and Absence Seizure and Comparison with Glutamate Antagonists

BACKGROUND

Riluzole (RLZ) has demonstrated neuroprotective effects in several neurological disorders. These neuroprotective effects seem to be mainly due to its ability to inhibit the excitatory glutamatergic neurotransmission, acting on different targets located both at the presynaptic and postsynaptic levels.

METHODS

In the present study, we evaluated the effects of Riluzole (RLZ) against limbic seizures, induced by AMPA, kainate, and NMDA receptor agonists in Sprague-Dawley rats, and in a well-validated genetic model of absence epilepsy, the WAG/Rij rat. Furthermore, in this latter model, we also studied the effect of RLZ in co-administration with the competitive NMDA receptor antagonist, CPP, or the non-competitive AMPA receptor antagonist, THIQ-10c, on spike-wave discharges (SWDs) in WAG/Rij rats, to understand the potential involvement of AMPA and NMDA receptors in the anti-absence effect of RLZ.

RESULTS

In Sprague-Dawley rats, RLZ pretreatment significantly reduced the limbic seizure severity induced by glutamatergic agonists, suggesting an antagonism of RLZ mainly on NMDA rather than non-NMDA receptors. RLZ also reduced SWD parameters in WAG/Rij rats. Interestingly, the co-administration of RLZ with CPP did not increase the anti-absence activity of RLZ in this model, advocating a competitive effect on the NMDA receptor. In contrast, the co-administration of RLZ with THIQ-10c induced an additive effect against absence seizure in WAG/Rij rats.

CONCLUSIONS

these results suggest that the antiepileptic effects of RLZ, in both seizure models, can be mainly due to the antagonism of the NMDA glutamatergic receptors.

Solid-Phase Synthesis of 2-Benzothiazolyl and 2-(Aminophenyl)benzothiazolyl Amino Acids and Peptides

2-benzothiazoles and 2-(aminophenyl)benzothiazoles represent biologically interesting heterocycles with high pharmacological activity. The combination of these heterocycles with amino acids and peptides is of special interest, as such structures combine the advantages of amino acids and peptides with the advantages of the 2-benzothiazolyl and 2-(aminophenyl)benzothiazolyl pharmacophore group. In this work, we developed an easy and efficient method for the solid-phase synthesis of 2-benzothiazolyl (BTH) and 2-(aminophenyl)benzothiazolyl (AP-BTH) C-terminal modified amino acids and peptides with high chiral purity.

CNM-Au8: an experimental agent for the treatment of amyotrophic lateral sclerosis (ALS)

INTRODUCTION

Two established disease-specific therapies for the treatment of amyotrophic lateral sclerosis (ALS) are riluzole and edaravone. Limitations of these medications include minimal progression slowing or survival benefit, and effectiveness only in selected populations, particularly for edaravone. AMX0035 and tofersen received US FDA approval in September 2022 and April 2023, respectively. However, phase 3 trials, further examining both medications' efficacy, are ongoing. CNM-Au8 is an efficient catalyst of energy metabolism and is therefore a potential disease-modifying treatment for ALS, a neurodegenerative condition in which there is bioenergetics impairment.

AREAS COVERED

In this review, we provide an overview of the current ALS treatment market, followed by a description of the pharmacodynamics and pharmacokinetics of CNM-Au8. The main preclinical and available early clinical evidence of CNM-Au8 is then described, as well as its potential as an ALS treatment.

EXPERT OPINION

Oral treatment with CNM-Au8 failed to meet primary clinical and electrodiagnostic endpoints in phase 2/3 clinical trials. Despite this failure, a number of exploratory endpoints included in phase 2/3 trials suggest CNM-Au8 has the potential to significantly slow clinical worsening, improve quality of life, and prolong survival in ALS. Further study of CNM-Au8 in a phase 3 clinical trial is currently underway.

Guideline "Motor neuron diseases" of the German Society of Neurology (Deutsche Gesellschaft für Neurologie)

INTRODUCTION

In 2021, the Deutsche Gesellschaft für Neurology published a new guideline on diagnosis and therapy of motor neuron disorders. Motor neuron disorders affect upper motor neurons in the primary motor cortex and/or lower motor neurons in the brain stem and spinal cord. The most frequent motor neuron disease amyotrophic lateral sclerosis (ALS) is a rapidly progressive disease with an average life expectancy of 2-4 years with a yearly incidence of 3.1/100,000 in Central Europe (Rosenbohm et al. in J Neurol 264(4):749-757, 2017. https://doi.org/10.1007/s00415-017-8413-3 ). It is considered a rare disease mainly due to its low prevalence as a consequence of short disease duration.

RECOMMENDATIONS

These guidelines comprise recommendations regarding differential diagnosis, neuroprotective therapies and multidisciplinary palliative care including management of respiration and nutrition as well as provision of assistive devices and end-of-life situations.

CONCLUSION

Diagnostic and therapeutic guidelines are necessary due the comparatively high number of cases and the aggressive disease course. Given the low prevalence and the severe impairment of patients, it is often impossible to generate evidence-based data so that ALS guidelines are partially dependent on expert opinion.

Emerging Trends in the Field of Inflammation and Proteinopathy in ALS/FTD Spectrum Disorder

Proteinopathy and neuroinflammation are two main hallmarks of neurodegenerative diseases. They also represent rare common events in an exceptionally broad landscape of genetic, environmental, neuropathologic, and clinical heterogeneity present in patients. Here, we aim to recount the emerging trends in amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD) spectrum disorder. Our review will predominantly focus on neuroinflammation and systemic immune imbalance in ALS and FTD, which have recently been highlighted as novel therapeutic targets. A common mechanism of most ALS and ~50% of FTD patients is dysregulation of TAR DNA-binding protein 43 (TDP-43), an RNA/DNA-binding protein, which becomes depleted from the nucleus and forms cytoplasmic aggregates in neurons and glia. This, in turn, via both gain and loss of function events, alters a variety of TDP-43-mediated cellular events. Experimental attempts to target TDP-43 aggregates or manipulate crosstalk in the context of inflammation will be discussed. Targeting inflammation, and the immune system in general, is of particular interest because of the high plasticity of immune cells compared to neurons.

Current State and Future Directions in the Therapy of ALS

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder affecting upper and lower motor neurons, with death resulting mainly from respiratory failure three to five years after symptom onset. As the exact underlying causative pathological pathway is unclear and potentially diverse, finding a suitable therapy to slow down or possibly stop disease progression remains challenging. Varying by country Riluzole, Edaravone, and Sodium phenylbutyrate/Taurursodiol are the only drugs currently approved in ALS treatment for their moderate effect on disease progression. Even though curative treatment options, able to prevent or stop disease progression, are still unknown, recent breakthroughs, especially in the field of targeting genetic disease forms, raise hope for improved care and therapy for ALS patients. In this review, we aim to summarize the current state of ALS therapy, including medication as well as supportive therapy, and discuss the ongoing developments and prospects in the field. Furthermore, we highlight the rationale behind the intense research on biomarkers and genetic testing as a feasible way to improve the classification of ALS patients towards personalized medicine.

Evidence of Metabolic Dysfunction in Amyotrophic Lateral Sclerosis (ALS) Patients and Animal Models

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects motor neurons, leading to muscle weakness, paralysis, and eventual death. Research from the past few decades has appreciated that ALS is not only a disease of the motor neurons but also a disease that involves systemic metabolic dysfunction. This review will examine the foundational research of understanding metabolic dysfunction in ALS and provide an overview of past and current studies in ALS patients and animal models, spanning from full systems to various metabolic organs. While ALS-affected muscle tissue exhibits elevated energy demand and a fuel preference switch from glycolysis to fatty acid oxidation, adipose tissue in ALS undergoes increased lipolysis. Dysfunctions in the liver and pancreas contribute to impaired glucose homeostasis and insulin secretion. The central nervous system (CNS) displays abnormal glucose regulation, mitochondrial dysfunction, and increased oxidative stress. Importantly, the hypothalamus, a brain region that controls whole-body metabolism, undergoes atrophy associated with pathological aggregates of TDP-43. This review will also cover past and present treatment options that target metabolic dysfunction in ALS and provide insights into the future of metabolism research in ALS.

Generation of an Open-Access Patient-Derived iPSC Biobank for Amyotrophic Lateral Sclerosis Disease Modelling

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting the upper and lower motor neurons, causing patients to lose control over voluntary movement, and leading to gradual paralysis and death. There is no cure for ALS, and the development of viable therapeutics has proved challenging, demonstrated by a lack of positive results from clinical trials. One strategy to address this is to improve the tool kit available for pre-clinical research. Here, we describe the creation of an open-access ALS iPSC biobank generated from patients carrying mutations in the TARDBP, FUS, ANXA11, ARPP21, and C9ORF72 genes, alongside healthy controls. To demonstrate the utilisation of these lines for ALS disease modelling, a subset of FUS-ALS iPSCs were differentiated into functionally active motor neurons. Further characterisation revealed an increase in cytoplasmic FUS protein and reduced neurite outgrowth in FUS-ALS motor neurons compared to the control. This proof-of-principle study demonstrates that these novel patient-derived iPSC lines can recapitulate specific and early disease-related ALS phenotypes. This biobank provides a disease-relevant platform for discovery of ALS-associated cellular phenotypes to aid the development of novel treatment strategies.

[Amyotrophic lateral sclerosis-Motor neuron disease with a wide clinical and genetic spectrum]

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is the most frequent motor neuron disease. Besides a timely diagnosis, precise knowledge of the clinical manifestations and differential diagnoses is essential. While most patients develop the disease at an older age, hereditary causes play a more frequent role in the juvenile forms.

OBJECTIVE

What is the current state of ALS diagnostics, which new treatment options exist?

MATERIAL AND METHOD

Literature search using Pubmed.gov.

RESULTS

The main focus is on an individualized symptomatic treatment as no curative treatment approaches exist. However, new insights into the genetic and pathophysiological principles of the different forms of ALS open the way for future disease-modifying treatment options.

CONCLUSION

In cases of a clinical suspicion of ALS molecular genetic diagnostics should be considered, particularly in juvenile and young adult patients, to exclude differential diagnoses and to enable patients access to new treatment approaches.

Pathologically mislocalised TDP-43 in upper motor neurons causes a die-forward spread of ALS-like pathogenic changes throughout the mouse corticomotor system

Alterations in upper motor neuron excitability are one of the earliest phenomena clinically detected in ALS, and in 97% of cases, the RNA/DNA binding protein, TDP-43, is mislocalised in upper and lower motor neurons. While these are two major pathological hallmarks in disease, our understanding of where disease pathology begins, and how it spreads through the corticomotor system, is incomplete. This project used a model where mislocalised TDP-43 was expressed in the motor cortex, to determine if localised cortical pathology could result in widespread corticomotor system degeneration. Mislocalised TDP-43 caused layer V excitatory neurons in the motor cortex to become hyperexcitable after 20 days of expression. Following cortical hyperexcitability, a spread of pathogenic changes through the corticomotor system was observed. By 30 days expression, there was a significant decrease in lower motor neuron number in the lumbar spinal cord. However, cell loss occurred selectively, with a significant loss in lumbar regions 1-3, and not lumbar regions 4-6. This regional vulnerability was associated with alterations in pre-synaptic excitatory and inhibitory proteins. Excitatory inputs (VGluT2) were increased in all lumbar regions, while inhibitory inputs (GAD65/67) were increased in lumbar regions 4-6 only. This data indicates that mislocalised TDP-43 in upper motor neurons can cause lower motor neuron degeneration. Furthermore, cortical pathology increased excitatory inputs to the spinal cord, to which local circuitry compensated with an upregulation of inhibition. These findings reveal how TDP-43 mediated pathology may spread through corticofugal tracts in ALS and identify a potential pathway for therapeutic intervention.

Amyotrophic lateral sclerosis: a neurodegenerative disorder poised for successful therapeutic translation

Amyotrophic lateral sclerosis (ALS) is a devastating disease caused by degeneration of motor neurons. As with all major neurodegenerative disorders, development of disease-modifying therapies has proven challenging for multiple reasons. Nevertheless, ALS is one of the few neurodegenerative diseases for which disease-modifying therapies are approved. Significant discoveries and advances have been made in ALS preclinical models, genetics, pathology, biomarkers, imaging and clinical readouts over the last 10-15 years. At the same time, novel therapeutic paradigms are being applied in areas of high unmet medical need, including neurodegenerative disorders. These developments have evolved our knowledge base, allowing identification of targeted candidate therapies for ALS with diverse mechanisms of action. In this Review, we discuss how this advanced knowledge, aligned with new approaches, can enable effective translation of therapeutic agents from preclinical studies through to clinical benefit for patients with ALS. We anticipate that this approach in ALS will also positively impact the field of drug discovery for neurodegenerative disorders more broadly.