Amyotrophic lateral sclerosis: moving towards a new classification system

New developments in the diagnosis and management of motor neuron disease

INTRODUCTION

Motor neuron disease (MND) is a devastating neurodegenerative disease characterized by progressive muscle weakness.

SOURCES OF DATA

PubMed, MEDLINE, and Cochrane databases were searched for articles to March 2024. Searches involved the terms 'motor neuron disease' or 'amyotrophic lateral sclerosis' and 'epidemiology', 'diagnosis', 'clinical', 'genetic', 'management', 'treatment', or 'trial'.

AREAS OF AGREEMENT

Evidence-based management involves riluzole, multidisciplinary care, provision of noninvasive ventilation and gastrostomy, and symptomatic treatments. Tofersen should be offered to treat SOD1-MND.

AREAS OF CONTROVERSY

Edaravone and Relyvrio are approved treatments in the USA, but insufficient evidence was found to support approval in the UK and Europe.

GROWING POINTS

The discovery of neurofilaments as MND biomarkers, growth of platform trials and development of novel therapies provide optimism for more powerful neuroprotective therapies.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further work should focus on the elucidation of environmental causes of MND, gene-environment interactions, and advanced cellular models of 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.

Synchronized motion of interface residues for evaluating protein-RNA complex binding affinity: Application to aptamer-mediated inhibition of TDP-43 aggregates

Investigating the binding between proteins and aptamers, such as peptides or RNA molecules, is of crucial importance both for understanding the molecular mechanisms that regulate cellular activities and for therapeutic applications in several pathologies. Here, a new computational procedure, employing mainly docking, clustering analysis, and molecular dynamics simulations, was designed to estimate the binding affinities between a protein and some RNA aptamers, through the investigation of the dynamical behavior of the predicted molecular complex. Using the state-of-the-art software catRAPID, we computationally designed a set of RNA aptamers interacting with the TAR DNA-binding protein 43 (TDP-43), a protein associated with several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). We thus devised a computational protocol to predict the RNA-protein molecular complex, so that the structural and dynamical behavior of such a complex can be investigated through extensive molecular dynamics simulation. We hypothesized that the coordinated and synchronized motion of the protein-binding residues, when in contact with RNA molecule, is a critical requisite in order to have a stable binding. Indeed, we calculated the motion covariance exhibited by the interface residues during molecular dynamics simulation: we tested the results against experimental measurements of binding affinity (in this case, the dissociation constant) for six RNA molecules, resulting in a linear correlation of about 0.9. Our findings suggest that the synchronized movement of interface residues plays a pivotal role in ensuring the stability within RNA-protein complexes, moreover providing insights into the contribution of each interface residue. This promising pipeline could thus contribute to the design of RNA aptamers interacting with proteins.

Advances in nanotechnology-assisted photodynamic therapy for neurological disorders: a comprehensive review

Neurological disorders such as neurodegenerative diseases and nervous system tumours affect more than one billion people throughout the globe. The physiological sensitivity of the nervous tissue limits the application of invasive therapies and leads to poor treatment and prognosis. One promising solution that has generated attention is Photodynamic therapy (PDT), which can potentially revolutionise the treatment landscape for neurological disorders. PDT attracted substantial recognition for anticancer efficacy and drug conjugation for targeted drug delivery. This review thoroughly explained the basic principles of PDT, scientific interventions and advances in PDT, and their complicated mechanism in treating brain-related pathologies. Furthermore, the merits and demerits of PDT in the context of neurological disorders offer a well-rounded perspective on its feasibility and challenges. In conclusion, this review encapsulates the significant potential of PDT in transforming the treatment landscape for neurological disorders, emphasising its role as a non-invasive, targeted therapeutic approach with multifaceted applications.

Overview of nomenclature and diagnosis of amyotrophic lateral sclerosis

The nomenclature of amyotrophic lateral sclerosis (ALS) currently is blurred, indistinct and no accurate and haven't been properly updated since the first description, which is far from being suitable for the current implementation of clinical practise and scientific research of ALS, and urgently need an solution. Furthermore, the current diagnostic criteria need also further been improved, because the current clinical diagnosis of ALS majorly depends on the clinical manifestations yet. Up to now, no any objective clinical auxiliary examination can be helpful to diagnose ALS besides the electromyogram identifying the lower motor neuron damage, which isn't conducive to early diagnosis and prolongs the time of ALS confirmed diagnosis. In this mini review, we discussed the current doubt about the nomenclature and diagnostic criteria of ALS, and prospected in order to further improve and normalize the nomenclature and diagnosis of ALS.

Development of a Sensitive and Reliable Meso Scale Discovery-Based Electrochemiluminescence Immunoassay to Quantify TDP-43 in Human Biofluids

Transactive response DNA-binding protein of 43 kDa (TDP-43) is a major component of pathological inclusions in various neurodegenerative disorders, including amyotrophic lateral sclerosis and frontotemporal lobar degeneration. The detection of TDP-43 in biofluids is crucial for the development of diagnostic and prognostic indicators of disease and therapeutic development for TDP-43-related proteinopathies. Despite its potential as a biomarker for numerous neurological disorders, the lack of a sensitive and reproducible TDP-43 assay hinders progress in TDP-43-based therapy development, underscoring the need for an effective and standardized method for accurate quantification. Addressing the limitations of sensitivity and reproducibility in existing assays, in this study, we developed and validated a highly sensitive electrochemiluminescence immunoassay on the Meso Scale Discovery platform. The assay demonstrated the detection of full-length TDP-43 in human biofluids with a limit of detection of 4pg/mL, a working range of 4-20,000 pg/mL, and a total assay time of 16 h. In this study, we developed and validated a sensitive immunoassay for the detection of full-length TDP-43 in human biofluids using the Meso Scale Discovery platform. We used this immunoassay to quantify TDP-43 levels in the plasma and serum of healthy controls and ALS patients. Our results indicate a reduction in full-length TDP-43 in the blood of ALS patients compared to healthy controls.

Prevalence and motor-functional correlates of frontotemporal-spectrum disorders in a large cohort of non-demented ALS patients

BACKGROUND

This study aimed at (1) delivering generalizable estimates of the prevalence of frontotemporal-spectrum disorders (FTSDs) in non-demented ALS patients and (2) exploring their motor-functional correlates.

METHODS

N = 808 ALS patients without FTD were assessed for motor-functional outcomes-i.e., disease duration, severity (ALSFRS-R), progression rate (ΔFS), and stage (King's and Milano-Torino-MiToS-systems)-cognition-via the cognitive section of the Edinburgh Cognitive and Behavioural ALS Screen (ECAS)-and behaviour-via the ECAS-Carer Interview. Neuropsychological phenotypes were retrieved via Strong's revised criteria-i.e., ALS cognitively and behaviourally normal (ALScbn) or cognitively and/or behaviourally impaired (ALSci/bi/cbi).

RESULTS

Defective ECAS-Total performances were detected in ~ 29% of patients, with the ECAS-Executive being failed by the highest number of patients (~ 30%), followed by the ECAS-Language, -Fluency, and -Memory (~ 15-17%) and -Visuospatial (~ %8). Apathy was the most frequent behavioural change (~ 28%), followed by loss of sympathy/empathy (~ 13%); remaining symptoms were reported in < 4% of patients. The distribution of Strong's classifications was as follows: ALScbn: 46.7%; ALSci/bi/cbi: 22.9%/20.0%/10.4%. Multinomial regressions on Strong's classifications revealed that lower ALSFRS-R scores were associated with a higher probability of ALSbi and ALScbi classifications (p ≤ .008). Higher King's and MiToS stages were associated with a higher probability of ALSbi classification (p ≤ .031).

CONCLUSIONS

FTSDs affect ~ 50% of non-demented ALS patients, with cognitive deficits being as frequent as behavioural changes. A higher degree of motor-functional involvement is associated with worse behavioural outcomes-with this link being weaker for cognitive deficits.

Serum neurofilament light chain in distinct phenotypes of amyotrophic lateral sclerosis: A longitudinal, multicenter study

OBJECTIVE

To assess the performance of serum neurofilament light chain (sNfL) in clinical phenotypes of amyotrophic lateral sclerosis (ALS).

METHODS

In 2949 ALS patients at 16 ALS centers in Germany and Austria, clinical characteristics and sNfL were assessed. Phenotypes were differentiated for two anatomical determinants: (1) upper and/or lower motor involvement (typical, typMN; upper/lower motor neuron predominant, UMNp/LMNp; primary lateral sclerosis, PLS) and (2) region of onset and propagation of motor neuron dysfunction (bulbar, limb, flail-arm, flail-leg, thoracic onset). Phenotypes were correlated to sNfL, progression, and survival.

RESULTS

Mean sNfL was - compared to typMN (75.7 pg/mL, n = 1791) - significantly lower in LMNp (45.1 pg/mL, n = 413), UMNp (58.7 pg/mL n = 206), and PLS (37.6 pg/mL, n = 84). Also, sNfL significantly differed in the bulbar (92.7 pg/mL, n = 669), limb (64.1 pg/mL, n = 1305), flail-arm (46.4 pg/mL, n = 283), flail-leg (53.6 pg/mL, n = 141), and thoracic (74.5 pg/mL, n = 96) phenotypes. Binary logistic regression analysis showed highest contribution to sNfL elevation for faster progression (odds ratio [OR] 3.24) and for the bulbar onset phenotype (OR 1.94). In contrast, PLS (OR 0.20), LMNp (OR 0.45), and thoracic onset (OR 0.43) showed reduced contributions to sNfL. Longitudinal sNfL (median 12 months, n = 2862) showed minor monthly changes (<0.2%) across all phenotypes. Correlation of sNfL with survival was confirmed (p < 0.001).

CONCLUSIONS

This study underscored the correlation of ALS phenotypes - differentiated for motor neuron involvement and region of onset/propagation - with sNfL, progression, and survival. These phenotypes demonstrated a significant effect on sNfL and should be recognized as independent confounders of sNfL analyses in ALS trials and clinical practice.

Physical therapy for the management of global function, fatigue and quality of life in amyotrophic lateral sclerosis: systematic review and meta-analyses

OBJECTIVES

To critically evaluate the effectiveness of physical therapy interventions in improving global function, quality of life and fatigue in individuals with amyotrophic lateral sclerosis (ALS).

DESIGN

Systematic review and meta-analyses.

DATA SOURCES

MEDLINE, EMBASE, Cochrane Library (CENTRAL) and Physiotherapy Evidence Database (PEDro) were searched through 31 January 2023.

ELIGIBILITY CRITERIA

We included randomised clinical trials (RCTs) that compared physical therapy interventions that act on global function, fatigue and quality of life in individuals with ALS with any other non-physiotherapeutic methods and techniques, placebo or non-intervention. The primary outcome measure was the evaluation of global function. Secondary outcomes were quality of life, fatigue and adverse events.

DATA EXTRACTION AND SYNTHESIS

Two independent authors used a researcher-developed extraction form and the Rayyan software to search, screen and code included studies. The risk of bias was assessed using the PEDro scale. Meta-analyses were conducted employing random effects. Outcomes were succinctly presented in Grading of Recommendations, Assessment, Development and Evaluation evidence profiles.

RESULTS

Our searches identified 39 415 references. After study selection, three studies were included in the review. Such studies involved 62 participants with a mean age of 54.6 years. In the evaluated trials, 40 were male, while 22 participants were female. Regarding the type of onset of the disease, 58 participants had spinal onset of ALS, and four had bulbar.

CONCLUSIONS

Physical therapy intervention may improve the global function of individuals with ALS in the short term; however, clinically, it was inconclusive. In terms of quality of life and fatigue, physical therapy intervention is not more effective than control in the short term. Adverse events are not increased by physical therapy intervention in the short term. Due to significant methodological flaws, small sample sizes, wide CIs and clinical interpretation, our confidence in the effect estimate is limited.

PROSPERO REGISTRATION NUMBER

CRD42021251350.

Racial Disparities in the Diagnosis and Prognosis of ALS Patients in the United States

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal disease with largely unknown etiology. This study compares racial differences in clinical characteristics of ALS patients enrolled in the National ALS Registry (Registry).

METHODS

Data from ALS patients who completed the Registry's online clinical survey during 2013-2022 were analyzed to determine characteristics such as site of onset, associated symptoms, time of symptom onset to diagnosis, and pharmacological and non-pharmacological interventions for White, Black, and other race patients.

RESULTS

Surveys were completed by 4242 participants. Findings revealed that Black ALS patients were more likely to be diagnosed at a younger age, to have arm or hand initial site of onset, and to experience pneumonia than were White ALS patients. ALS patients of other races were more likely than White ALS patients to be diagnosed at a younger age and to experience twitching. The mean interval between the first sign of weakness and an ALS diagnosis for Black patients was almost 24 months, statistically greater than that of White (p = 0.0374; 16 months) and other race patients (p = 0.0518; 15.8 months). The mean interval between problems with speech until diagnosis was shorter for White patients (6.3 months) than for Black patients (17.7 months) and other race patients (14.8 months).

CONCLUSIONS AND RELEVANCE

Registry data shows racial disparities still exist in the diagnosis and clinical characteristics of ALS patients. Increased recruitment of non-White ALS patients and better characterization of symptom onset between races might aid clinicians in diagnosing ALS sooner, leading to earlier therapeutic interventions.

Clinicopathological correlates in the frontotemporal lobar degeneration-motor neuron disease spectrum

Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease (MND) that shares a common clinical, genetic and pathologic spectrum with frontotemporal dementia (FTD). It is highly heterogeneous in its presentation and features. Up to 50% of patients with MND develop cognitive-behavioural symptoms during the course of the disease, meeting criteria for FTD in 10%-15% of cases. In the absence of a precise biomarker, neuropathology is still a valuable tool to understand disease nosology, reach a definite diagnostic confirmation and help define specific subgroups of patients with common phenotypic, genetic and biomarker profiles. However, few neuropathological series have been published, and the frequency of frontotemporal lobar degeneration (FTLD) in MND is difficult to estimate. In this work we describe a large clinicopathological series of MND patients, analysing the frequency of concurrent FTLD changes and trying to define specific subgroups of patients based on their clinical, genetic and pathological characteristics. We performed an observational, retrospective, multicentre case study. We included all cases meeting neuropathological criteria for MND from the Neurological Tissue Bank of the FRCB-IDIBAPS-Hospital Clínic Barcelona Biobank between 1994 and 2022, regardless of their last clinical diagnosis. While brain donation is encouraged in all patients, it is performed in very few, and representativeness of the cohort might not be precise for all patients with MND. We retrospectively reviewed clinical and neuropathological data and describe the main clinical, genetic and pathogenic features, comparing neuropathologic groups between MND with and without FTLD changes and aiming to define specific subgroups. We included brain samples from 124 patients, 44 of whom (35.5%) had FTLD neuropathologic features (i.e. FTLD-MND). Pathologic TDP-43 aggregates were present in 93.6% of the cohort and were more extensive (higher Brettschneider stage) in those with concurrent FTLD (P < 0.001). Motor symptom onset was more frequent in the bulbar region in FTLD-MND cases than in those with isolated MND (P = 0.023), with no differences in survival. We observed a better clinicopathological correlation in the MND group than in the FTLD-MND group (93.8% versus 61.4%; P < 0.001). Pathogenic genetic variants were more common in the FTLD-MND group, especially C9orf72. We describe a frequency of FTLD of 35.5% in our series of neuropathologically confirmed cases of MND. The FTLD-MND spectrum is highly heterogeneous in all aspects, especially in patients with FTLD, in whom it is particularly difficult to define specific subgroups. In the absence of definite biomarkers, neuropathology remains a valuable tool for a definite diagnosis, increasing our knowledge in disease nosology.

Coffee and amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterized by progressive loss of motor neurons. The effective treatments for ALS remain elusive, necessitating exploration into novel preventive strategies. ALS pathogenesis is triggered by oxidative stress which results in neuroinflammation, exicitotoxicity and neuronal cell death. Nutritional mechanism for halting progression of neurodegeneration is through dietary compounds with antioxidants, anti-inflammatory or neuromodulating activity. Coffee is a widely consumed beverage made up of polyphenols, caffeine and other compounds with possible antioxidants and neuro-protective roles. It is important to say that various epidemiological studies have documented association between coffee intake and ALS. This chapter is aimed to present a comprehensive review of existing literature on coffee consumption and ALS, involving epidemiological studies, preclinical research, and its mechanism of actions in animal model of ALS. It highlights key findings regarding the potential neuroprotective properties of coffee constituents such as caffeine, polyphenols, and other bioactive compounds. Furthermore, it discusses possible pathways through which coffee may modulate ALS pathogenesis, including suppressing oxidative stress and neuroinflammation while boosting adenosine function via the adenosine receptor two on the motor neuron cells membrane in the spinal cord to enhance motor function via the corticospinal tract. Overall, this chapter underscores the significance of further research to unravel the specific mechanisms by which coffee exerts its neuroprotective effects in ALS, with the ultimate goal of identifying dietary strategies for ALS prevention and management.

Update on recent advances in amyotrophic lateral sclerosis

In the last few years, our understanding of disease molecular mechanisms underpinning ALS has advanced greatly, allowing the first steps in translating into clinical practice novel research findings, including gene therapy approaches. Similarly, the recent advent of assistive technologies has greatly improved the possibility of a more personalized approach to supportive and symptomatic care, in the context of an increasingly complex multidisciplinary line of actions, which remains the cornerstone of ALS management. Against this rapidly growing background, here we provide an comprehensive update on the most recent studies that have contributed towards our understanding of ALS pathogenesis, the latest results from clinical trials as well as the future directions for improving the clinical management of ALS patients.

New clinical insight in amyotrophic lateral sclerosis and innovative clinical development from the non-profit repurposing trial of the old drug guanabenz

Drug repurposing is considered a valid approach to accelerate therapeutic solutions for rare diseases. However, it is not as widely applied as it could be, due to several barriers that discourage both industry and academic institutions from pursuing this path. Herein we present the case of an academic multicentre study that considered the repurposing of the old drug guanabenz as a therapeutic strategy in amyotrophic lateral sclerosis. The difficulties encountered are discussed as an example of the barriers that academics involved in this type of study may face. Although further development of the drug for this target population was hampered for several reasons, the study was successful in many ways. Firstly, because the hypothesis tested was confirmed in a sub-population, leading to alternative innovative solutions that are now under clinical investigation. In addition, the study was informative and provided new insights into the disease, which are now giving new impetus to laboratory research. The message from this example is that even a repurposing study with an old product has the potential to generate innovation and interest from industry partners, provided it is based on a sound rationale, the study design is adequate to ensure meaningful results, and the investigators keep the full clinical development picture in mind.

Acceptance and Commitment Therapy plus usual care for improving quality of life in people with motor neuron disease (COMMEND): a multicentre, parallel, randomised controlled trial in the UK

BACKGROUND

Motor neuron disease is a progressive, fatal neurodegenerative disease for which there is no cure. Acceptance and Commitment Therapy (ACT) is a psychological therapy incorporating acceptance, mindfulness, and behaviour change techniques. We aimed to evaluate the effectiveness of ACT plus usual care, compared with usual care alone, for improving quality of life in people with motor neuron disease.

METHODS

We conducted a parallel, multicentre, two-arm randomised controlled trial in 16 UK motor neuron disease care centres or clinics. Eligible participants were aged 18 years or older with a diagnosis of definite or laboratory-supported probable, clinically probable, or possible familial or sporadic amyotrophic lateral sclerosis; progressive muscular atrophy; or primary lateral sclerosis; which met the World Federation of Neurology's El Escorial diagnostic criteria. Participants were randomly assigned (1:1) to receive up to eight sessions of ACT adapted for people with motor neuron disease plus usual care or usual care alone by a web-based system, stratified by site. Participants were followed up at 6 months and 9 months post-randomisation. Outcome assessors and trial statisticians were masked to treatment allocation. The primary outcome was quality of life using the McGill Quality of Life Questionnaire-Revised (MQOL-R) at 6 months post-randomisation. Primary analyses were multi-level modelling and modified intention to treat among participants with available data. This trial was pre-registered with the ISRCTN Registry (ISRCTN12655391).

FINDINGS

Between Sept 18, 2019, and Aug 31, 2022, 435 people with motor neuron disease were approached for the study, of whom 206 (47%) were assessed for eligibility, and 191 were recruited. 97 (51%) participants were randomly assigned to ACT plus usual care and 94 (49%) were assigned to usual care alone. 80 (42%) of 191 participants were female and 111 (58%) were male, and the mean age was 63·1 years (SD 11·0). 155 (81%) participants had primary outcome data at 6 months post-randomisation. After controlling for baseline scores, age, sex, and therapist clustering, ACT plus usual care was superior to usual care alone for quality of life at 6 months (adjusted mean difference on the MQOL-R of 0·66 [95% CI 0·22-1·10]; d=0·46 [0·16-0·77]; p=0·0031). Moderate effect sizes were clinically meaningful. 75 adverse events were reported, 38 of which were serious, but no adverse events were deemed to be associated with the intervention.

INTERPRETATION

ACT plus usual care is clinically effective for maintaining or improving quality of life in people with motor neuron disease. As further evidence emerges confirming these findings, health-care providers should consider how access to ACT, adapted for the specific needs of people with motor neuron disease, could be provided within motor neuron disease clinical services.

FUNDING

National Institute for Health and Care Research Health Technology Assessment and Motor Neurone Disease Association.

Evaluating emerging drugs in phase II & III for the treatment of amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic Lateral Sclerosis is a rapidly progressive motor neuron disorder causing severe disability and premature death. Owing to the advances in uncovering ALS pathophysiology, efficient clinical trial design and research advocacy program, several disease-modifying drugs have been approved for treating ALS. Despite this progress, ALS remains a rapidly disabling and life shortening condition. There is a critical need for more effective therapies.

AREAS COVERED

Here, we reviewed the emerging ALS therapeutics undergoing phase II & III clinical trials. To identify the investigational drugs, we searched ALS and phase II/III trials that are active and recruiting or not yet recruiting on clinicaltrials.gov and Pharmaprojects database.

EXPERT OPINION

The current pipeline is larger and more diverse than ever, with drugs targeting potential genetic and retroviral causes of ALS and drugs targeting a wide array of downstream pathways, including RNA metabolism, protein aggregation, integrated stress response and neuroinflammation.We remain most excited about those that target direct causes of ALS, e.g. antisense oligonucleotides targeting causative genes. Drugs that eliminate abnormal protein aggregates are also up-and-coming. Eventually, because of the heterogeneity of ALS pathophysiology, biomarkers that determine which biological events are most important for an individual ALS patient are needed.

Intermuscular coherence as an early biomarker for amyotrophic lateral sclerosis: The protocol for a prospective, multicenter study

OBJECTIVE

To describe the protocol of a prospective study to test the validity of intermuscular coherence (IMC) as a diagnostic tool and biomarker of upper motor neuron degeneration in amyotrophic lateral sclerosis (ALS).

METHODS

This is a multicenter, prospective study. IMC of muscle pairs in the upper and lower limbs is gathered in ∼650 subjects across three groups using surface electrodes and conventional electromyography (EMG) machines. The following subjects will be tested: 1) neurotypical controls; 2) patients with symptomatology suggestive for early ALS but not meeting probable or definite ALS by Awaji Criteria; 3) patients with a known ALS mimic. The recruitment period is between 3/31/2021 and 12/31/2025. Written consent will be sought from the subject or the subject's legally authorized representative during enrollment.

RESULTS

The endpoints of this study include: 1) whether adding IMC to the Awaji ALS criteria improve its sensitivity in early ALS and can allow for diagnosis earlier; 2) constructing a database of IMC across different ages, genders, and ethnicities.

SIGNIFICANCE

This study may validate a new inexpensive, painless, and widely available tool for the diagnosis of ALS.

Edaravone counteracts redox and metabolic disruptions in an emerging zebrafish model of sporadic ALS

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which the death of motor neurons leads to loss of muscle function. Additionally, cognitive and circadian disruptions are common in ALS patients, contributing to disease progression and burden. Most ALS cases are sporadic, and environmental exposures contribute to their aetiology. However, animal models of these sporadic ALS cases are scarce. The small vertebrate zebrafish is a leading organism to model neurodegenerative diseases; previous studies have proposed bisphenol A (BPA) or β-methylamino-l-alanine (BMAA) exposure to model sporadic ALS in zebrafish, damaging motor neurons and altering motor responses. Here we characterise the face and predictive validity of sporadic ALS models, showing their potential for the mechanistic study of ALS drugs. We phenotypically characterise the BPA and BMAA-induced models, going beyond motor activity and motor axon morphology, to include circadian, redox, proteostasis, and metabolomic phenotypes, and assessing their predictive validity for ALS modelling. BPA or BMAA exposure induced concentration-dependent activity impairments. Also, exposure to BPA but not BMAA induced motor axonopathy and circadian alterations in zebrafish larvae. Our further study of the BPA model revealed loss of habituation to repetitive startles, increased oxidative damage, endoplasmic reticulum (ER) stress, and metabolome abnormalities. The BPA-induced model shows predictive validity, since the approved ALS drug edaravone counteracted BPA-induced motor phenotypes, ER stress, and metabolic disruptions. Overall, BPA exposure is a promising model of ALS-related redox and ER imbalances, contributing to fulfil an unmet need for validated sporadic ALS models.

Pyruvate dehydrogenase kinase 2 knockdown restores the ability of amyotrophic lateral sclerosis-linked SOD1G93A rat astrocytes to support motor neuron survival by increasing mitochondrial respiration

Amyotrophic lateral sclerosis (ALS) is characterized by progressive motor neuron (MN) degeneration. Various studies using cellular and animal models of ALS indicate that there is a complex interplay between MN and neighboring non-neuronal cells, such as astrocytes, resulting in noncell autonomous neurodegeneration. Astrocytes in ALS exhibit a lower ability to support MN survival than nondisease-associated ones, which is strongly correlated with low-mitochondrial respiratory activity. Indeed, pharmacological inhibition of pyruvate dehydrogenase kinase (PDK) led to an increase in the mitochondrial oxidative phosphorylation pathway as the primary source of cell energy in SOD1G93A astrocytes and restored the survival of MN. Among the four PDK isoforms, PDK2 is ubiquitously expressed in astrocytes and presents low expression levels in neurons. Herein, we hypothesize whether selective knockdown of PDK2 in astrocytes may increase mitochondrial activity and, in turn, reduce SOD1G93A-associated toxicity. To assess this, cultured neonatal SOD1G93A rat astrocytes were incubated with specific PDK2 siRNA. This treatment resulted in a reduction of the enzyme expression with a concomitant decrease in the phosphorylation rate of the pyruvate dehydrogenase complex. In addition, PDK2-silenced SOD1G93A astrocytes exhibited restored mitochondrial bioenergetics parameters, adopting a more complex mitochondrial network. This treatment also decreased lipid droplet content in SOD1G93A astrocytes, suggesting a switch in energetic metabolism. Significantly, PDK2 knockdown increased the ability of SOD1G93A astrocytes to support MN survival, further supporting the major role of astrocyte mitochondrial respiratory activity in astrocyte-MN interactions. These results suggest that PDK2 silencing could be a cell-specific therapeutic tool to slow the progression of ALS.

Ensemble-imbalance-based classification for amyotrophic lateral sclerosis prognostic prediction: identifying short-survival patients at diagnosis

Prognosticating Amyotrophic Lateral Sclerosis (ALS) presents a formidable challenge due to patients exhibiting different onset sites, progression rates, and survival times. In this study, we have developed and evaluated Machine Learning (ML) algorithms that integrate Ensemble and Imbalance Learning techniques to classify patients into Short and Non-Short survival groups based on data collected during diagnosis. We aimed to identify individuals at high risk of mortality within 24 months of symptom onset through analysis of patient data commonly encountered in daily clinical practice. Our Ensemble-Imbalance approach underwent evaluation employing six ML algorithms as base classifiers. Remarkably, our results outperformed those of individual algorithms, achieving a Balanced Accuracy of 88% and a Sensitivity of 96%. Additionally, we used the Shapley Additive Explanations framework to elucidate the decision-making process of the top-performing model, pinpointing the most important features and their correlations with the target prediction. Furthermore, we presented helpful tools to visualize and compare patient similarities, offering valuable insights. Confirming the obtained results, our approach could aid physicians in devising personalized treatment plans at the time of diagnosis or serve as an inclusion/exclusion criterion in clinical trials.

PCDHA9 as a candidate gene for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. To identify additional genetic factors, we analyzed exome sequences in a large cohort of Chinese ALS patients and found a homozygous variant (p.L700P) in PCDHA9 in three unrelated patients. We generated Pcdhα9 mutant mice harboring either orthologous point mutation or deletion mutation. These mice develop progressive spinal motor loss, muscle atrophy, and structural/functional abnormalities of the neuromuscular junction, leading to paralysis and early lethality. TDP-43 pathology is detected in the spinal motor neurons of aged mutant mice. Mechanistically, we demonstrate that Pcdha9 mutation causes aberrant activation of FAK and PYK2 in aging spinal cord, and dramatically reduced NKA-α1 expression in motor neurons. Our single nucleus multi-omics analysis reveals disturbed signaling involved in cell adhesion, ion transport, synapse organization, and neuronal survival in aged mutant mice. Together, our results present PCDHA9 as a potential ALS gene and provide insights into its pathogenesis.

Unraveling the Heterogeneity of ALS-A Call to Redefine Patient Stratification for Better Outcomes in Clinical Trials

Despite tremendous efforts in basic research and a growing number of clinical trials aiming to find effective treatments, amyotrophic lateral sclerosis (ALS) remains an incurable disease. One possible reason for the lack of effective causative treatment options is that ALS may not be a single disease entity but rather may represent a clinical syndrome, with diverse genetic and molecular causes, histopathological alterations, and subsequent clinical presentations contributing to its complexity and variability among individuals. Defining a way to subcluster ALS patients is becoming a central endeavor in the field. Identifying specific clusters and applying them in clinical trials could enable the development of more effective treatments. This review aims to summarize the available data on heterogeneity in ALS with regard to various aspects, e.g., clinical, genetic, and molecular.

Evidence based on Mendelian randomization and colocalization analysis strengthens causal relationships between structural changes in specific brain regions and risk of amyotrophic lateral sclerosis

Background

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the degeneration of motor neurons in the brain and spinal cord with a poor prognosis. Previous studies have observed cognitive decline and changes in brain morphometry in ALS patients. However, it remains unclear whether the brain structural alterations contribute to the risk of ALS. In this study, we conducted a bidirectional two-sample Mendelian randomization (MR) and colocalization analysis to investigate this causal relationship.

Methods

Summary data of genome-wide association study were obtained for ALS and the brain structures, including surface area (SA), thickness and volume of subcortical structures. Inverse-variance weighted (IVW) method was used as the main estimate approach. Sensitivity analysis was conducted detect heterogeneity and pleiotropy. Colocalization analysis was performed to calculate the posterior probability of causal variation and identify the common genes.

Results

In the forward MR analysis, we found positive associations between the SA in four cortical regions (lingual, parahippocampal, pericalcarine, and middle temporal) and the risk of ALS. Additionally, decreased thickness in nine cortical regions (caudal anterior cingulate, frontal pole, fusiform, inferior temporal, lateral occipital, lateral orbitofrontal, pars orbitalis, pars triangularis, and pericalcarine) was significantly associated with a higher risk of ALS. In the reverse MR analysis, genetically predicted ALS was associated with reduced thickness in the bankssts and increased thickness in the caudal middle frontal, inferior parietal, medial orbitofrontal, and superior temporal regions. Colocalization analysis revealed the presence of shared causal variants between the two traits.

Conclusion

Our results suggest that altered brain morphometry in individuals with high ALS risk may be genetically mediated. The causal associations of widespread multifocal extra-motor atrophy in frontal and temporal lobes with ALS risk support the notion of a continuum between ALS and frontotemporal dementia. These findings enhance our understanding of the cortical structural patterns in ALS and shed light on potentially viable therapeutic targets.

Multimodal layer modelling reveals in vivo pathology in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a rapidly progressing neurodegenerative disease characterized by the loss of motor control. Current understanding of ALS pathology is largely based on post-mortem investigations at advanced disease stages. A systematic in vivo description of the microstructural changes that characterize early stage ALS, and their subsequent development, is so far lacking. Recent advances in ultra-high field (7 T) MRI data modelling allow us to investigate cortical layers in vivo. Given the layer-specific and topographic signature of ALS pathology, we combined submillimetre structural 7 T MRI data (qT1, QSM), functional localizers of body parts (upper limb, lower limb, face) and layer modelling to systematically describe pathology in the primary motor cortex (M1), in 12 living ALS patients with reference to 12 matched controls. Longitudinal sampling was performed for a subset of patients. We calculated multimodal pathology maps for each layer (superficial layer, layer 5a, layer 5b, layer 6) of M1 to identify hot spots of demyelination, iron and calcium accumulation in different cortical fields. We show preserved mean cortical thickness and layer architecture of M1, despite significantly increased iron in layer 6 and significantly increased calcium in layer 5a and superficial layer, in patients compared to controls. The behaviourally first-affected cortical field shows significantly increased iron in L6 compared to other fields, while calcium accumulation is atopographic and significantly increased in the low myelin borders between cortical fields compared to the fields themselves. A subset of patients with longitudinal data shows that the low myelin borders are particularly disrupted and that calcium hot spots, but to a lesser extent iron hot spots, precede demyelination. Finally, we highlight that a very slow progressing patient (Patient P4) shows a distinct pathology profile compared to the other patients. Our data show that layer-specific markers of in vivo pathology can be identified in ALS patients with a single 7 T MRI measurement after first diagnosis, and that such data provide critical insights into the individual disease state. Our data highlight the non-topographic architecture of ALS disease spread and the role of calcium, rather than iron accumulation, in predicting future demyelination. We also highlight a potentially important role of low myelin borders, that are known to connect to multiple areas within the M1 architecture, in disease spread. Finally, the distinct pathology profile of a very-slow progressing patient (Patient P4) highlights a distinction between disease duration and progression. Our findings demonstrate the importance of in vivo histology imaging for the diagnosis and prognosis of neurodegenerative diseases such as ALS.

Misdiagnosis of amyotrophic lateral sclerosis in clinical practice in Europe and the USA: a patient chart review and physician survey

OBJECTIVE

Delays in amyotrophic lateral sclerosis (ALS) diagnosis can result in compromised disease management and unnecessary costs. We examined the extent of ALS misdiagnosis in the US and Europe.

METHODS

Data were collected via the Adelphi ALS Disease Specific Programme™, a cross-sectional survey of physicians and a medical chart review of their consulting patients with ALS in France, Germany, Italy, Spain, the UK (EU5), and the US. Between July 2020 and March 2021, eligible physicians (primary speciality neurology, active involvement in managing patients with ALS) abstracted data from patients (≥18 years old) with confirmed ALS.

RESULTS

Overall, 138 physicians completed the survey (EU5 107, US 31), with data reviewed from 795 patient medical charts (EU5 568, US 227); 278 (35.0%) patients (EU5 183 [32.2%], US 95 [41.9%]) had received ≥1 initial misdiagnosis based on symptoms later attributed to ALS. Mean (SD) time from symptom onset to first healthcare professional consultation was 3.8 (5.2) months (EU5 4.3 [4.8] months, US 2.6 [5.8] months). Mean (SD) time from symptom onset to ALS diagnosis was 8.2 (12.5) months (EU5 9.6 [14.0] months, US 5.0 [6.8] months) and increased to 10.4 (17.9) for patients with a misdiagnosis (compared with 6.9 [7.2] for patients with no misdiagnosis). Physician-identified barriers to timely ALS diagnosis included the similarity of symptoms to other conditions and delayed referral to neurologists.

CONCLUSIONS

Misdiagnosis of ALS is frequent, with a protracted diagnostic pathway. Targeted education of patients and physicians about signs and symptoms and benefits of prompt referral to multidisciplinary care are needed.

Shared and Unique Disease Pathways in Amyotrophic Lateral Sclerosis and Parkinson's Disease Unveiled in Peripheral Blood Mononuclear Cells

Recent evidence supports an association between amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Indeed, prospective population-based studies demonstrated that about one-third of ALS patients develop parkinsonian (PK) signs, even though different neuronal circuitries are involved. In this context, proteomics represents a valuable tool to identify unique and shared pathological pathways. Here, we used two-dimensional electrophoresis to obtain the proteomic profile of peripheral blood mononuclear cells (PBMCs) from PD and ALS patients including a small cohort of ALS patients with parkinsonian signs (ALS-PK). After the removal of protein spots correlating with confounding factors, we applied a sparse partial least square discriminant analysis followed by recursive feature elimination to obtain two protein classifiers able to discriminate (i) PD and ALS patients (30 spots) and (ii) ALS-PK patients among all ALS subjects (20 spots). Functionally, the glycolysis pathway was significantly overrepresented in the first signature, while extracellular interactions and intracellular signaling were enriched in the second signature. These results represent molecular evidence at the periphery for the classification of ALS-PK as ALS patients that manifest parkinsonian signs, rather than comorbid patients suffering from both ALS and PD. Moreover, we confirmed that low levels of fibrinogen in PBMCs is a characteristic feature of PD, also when compared with another movement disorder. Collectively, we provide evidence that peripheral protein signatures are a tool to differentially investigate neurodegenerative diseases and highlight altered biochemical pathways.

Heterogeneity of cortical pTDP-43 inclusion morphologies in amyotrophic lateral sclerosis

BACKGROUND

Despite the presence of significant cortical pTDP-43 inclusions of heterogeneous morphologies in patients diagnosed with amyotrophic lateral sclerosis (ALS), pathological subclassification is routinely performed in the minority of patients with concomitant frontotemporal dementia (FTD).

OBJECTIVE

In order to improve current understanding of the presence and relevance of pathological pTDP-43 subtypes in ALS, the present study examined the pattern of cortical pTDP-43 aggregates in 61 ALS cases without FTD.

RESULTS

Based on the presence, morphology and composition of pTDP-43 pathology, three distinct ALS-TDP subtypes were delineated: (1) A predominant pattern of pTDP-43 granulofilamentous neuronal inclusions (GFNIs) and grains that were immuno-negative for p62 was identified in 18% of cases designated ALS-TDP type E; (2) neuronal cytoplasmic inclusions (NCIs) that were immuno-positive for both pTDP-43 and p62 were observed in 67% of cases assigned ALS-TDP type B; and (3) scarce cortical pTDP-43 and p62 aggregates were identified in 15% of cases coined ALS-TDP type SC (scarce cortical). Quantitative analyses revealed a significantly greater burden of pTDP-43 GFNI and grains in ALS-TDP type E. Principal component analysis demonstrated significant relationships between GFNIs, grains and ALS-TDP subtypes to support the distinction of subtypes E and B. No significant difference in age at death or disease duration was found between ALS-TDP subgroups to suggest that these subtypes represent earlier or later stages of the same disease process. Instead, a significantly higher ALS-TDP stage, indicating greater topographical spread of pTDP-43, was identified in ALS-TDP type E. Alzheimer's disease neuropathological change (ABC score ≥ intermediate) and Lewy body disease (Braak stage ≥ IV) was more prevalent in the ALS-TDP type SC cohort, which also demonstrated a significantly lower overall cognitive score.

CONCLUSION

In summary, the present study demonstrates that ALS-TDP does not represent a single homogenous neuropathology. We propose the subclassification of ALS-TDP into three distinct subtypes using standard immuno-stains for pTDP-43 and p62 in the motor cortex, which is routinely sampled and evaluated for diagnostic neuropathological characterisation of ALS. We propose that future studies specify both clinicopathological group and pTDP-43 subtype to advance current understanding of the pathogenesis of clinical phenotypes in pTDP-43 proteinopathies, which will have significant relevance to the development of targeted therapies for this heterogeneous disorder.

TBK1 variants in Chinese patients with amyotrophic lateral sclerosis: Genetic analysis and clinical features

BACKGROUND AND PURPOSE

Haploinsufficiency of TANK-binding kinase 1 (TBK1) loss-of-function (LoF) variants has been shown to be pathogenic in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, the genetic spectrum of TBK1 and clinical features of ALS patients with TBK1 variants remain largely unknown in Asians.

METHODS

Genetic analysis was performed on 2011 Chinese ALS patients. Software was used to predict the deleteriousness of missense variants in TBK1. In addition, PubMed, Embase and Web of Science were searched for related literature.

RESULTS

Twenty-six TBK1 variants were identified in 33 of 2011 ALS patients, including six novel LoF variants (0.3%) and 20 rare missense variants, 12 of which were predicted to be deleterious (0.6%). In addition to TBK1 variants, 11 patients had other ALS-related gene variants. Forty-two previous studies found that the frequency of TBK1 variants was 1.81% in ALS/FTD patients. The frequency of TBK1 LoF variants in ALS was 0.5% (Asians 0.4%; Caucasian 0.6%) and that of missense variants was 0.8% (Asians 1.0%; Caucasian 0.8%). ALS patients with TBK1 LoF variants affecting the kinase domain had a significantly younger age of onset than patients carrying LoF variants affecting the coiled coil domains CCD1 and CCD2. FTD has a frequency of 10% in Caucasian ALS patients with TBK1 LoF variants, which was not found in our cohort.

CONCLUSION

Our study expanded the genotypic spectrum of ALS patients with TBK1 variants and found that the clinical manifestations of TBK1 carriers are diverse.

Sonographic Phrenic Nerve Changes in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects both the upper and lower motor neurons in the nervous system, causing muscle weakness and severe disability. The progressive course of the disease reduces the functional capacity of the affected patients, limits daily activities, and leads to complete dependence on caregivers, ultimately resulting in a fatal outcome. Respiratory dysfunction mostly occurs later in the disease and is associated with a worse prognosis. Forty-six participants were included in our study, with 23 patients in the ALS group and 23 individuals in the control group. The ultrasound examination of the phrenic nerve (PN) was performed by two authors using a high-resolution "Philips EPIQ 7" ultrasound machine with a linear 4-18 MHz transducer. Our study revealed that the phrenic nerve is significantly smaller on both sides in ALS patients compared to the control group (p < 0.001). Only one significant study on PN ultrasound in ALS, conducted in Japan, also showed significant results (p < 0.00001). These small studies are particularly promising, as they suggest that ultrasound findings could serve as an additional diagnostic tool for ALS.

UNC13A in amyotrophic lateral sclerosis: from genetic association to therapeutic target

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with limited treatment options and an incompletely understood pathophysiology. Although genomewide association studies (GWAS) have advanced our understanding of the disease, the precise manner in which risk polymorphisms contribute to disease pathogenesis remains unclear. Of relevance, GWAS have shown that a polymorphism (rs12608932) in the UNC13A gene is associated with risk for both ALS and frontotemporal dementia (FTD). Homozygosity for the C-allele at rs12608932 modifies the ALS phenotype, as these patients are more likely to have bulbar-onset disease, cognitive impairment and FTD at baseline as well as shorter survival. UNC13A is expressed in neuronal tissue and is involved in maintaining synaptic active zones, by enabling the priming and docking of synaptic vesicles. In the absence of functional TDP-43, risk variants in UNC13A lead to the inclusion of a cryptic exon in UNC13A messenger RNA, subsequently leading to nonsense mediated decay, with loss of functional protein. Depletion of UNC13A leads to impaired neurotransmission. Recent discoveries have identified UNC13A as a potential target for therapy development in ALS, with a confirmatory trial with lithium carbonate in UNC13A cases now underway and future approaches with antisense oligonucleotides currently under consideration. Considering UNC13A is a potent phenotypic modifier, it may also impact clinical trial outcomes. This present review describes the path from the initial discovery of UNC13A as a risk gene in ALS to the current therapeutic options being explored and how knowledge of its distinct phenotype needs to be taken into account in future trials.

Acceptance and Commitment Therapy for people living with motor neuron disease: an uncontrolled feasibility study

BACKGROUND

Motor neuron disease (MND) is a fatal, progressive neurodegenerative disease that causes progressive weakening and wasting of limb, bulbar, thoracic and abdominal muscles. Clear evidence-based guidance on how psychological distress should be managed in people living with MND (plwMND) is lacking. Acceptance and Commitment Therapy (ACT) is a form of psychological therapy that may be particularly suitable for this population. However, to the authors' knowledge, no study to date has evaluated ACT for plwMND. Consequently, the primary aim of this uncontrolled feasibility study was to examine the feasibility and acceptability of ACT for improving the psychological health of plwMND.

METHODS

PlwMND aged ≥ 18 years were recruited from 10 UK MND Care Centres/Clinics. Participants received up to 8 one-to-one ACT sessions, developed specifically for plwMND, plus usual care. Co-primary feasibility and acceptability outcomes were uptake (≥ 80% of the target sample [N = 28] recruited) and initial engagement with the intervention (≥ 70% completing ≥ 2 sessions). Secondary outcomes included measures of quality of life, anxiety, depression, disease-related functioning, health status and psychological flexibility in plwMND and quality of life and burden in caregivers. Outcomes were assessed at baseline and 6 months.

RESULTS

Both a priori indicators of success were met: 29 plwMND (104%) were recruited and 76% (22/29) attended ≥ 2 sessions. Attrition at 6-months was higher than anticipated (8/29, 28%), but only two dropouts were due to lack of acceptability of the intervention. Acceptability was further supported by good satisfaction with therapy and session attendance. Data were possibly suggestive of small improvements in anxiety and psychological quality of life from baseline to 6 months in plwMND, despite a small but expected deterioration in disease-related functioning and health status.

CONCLUSIONS

There was good evidence of acceptability and feasibility. Limitations included the lack of a control group and small sample size, which complicate interpretation of findings. A fully powered RCT to evaluate the clinical and cost-effectiveness of ACT for plwMND is underway.

TRIAL REGISTRATION

The study was pre-registered with the ISRCTN Registry (ISRCTN12655391).

Unraveling Molecular and Genetic Insights into Neurodegenerative Diseases: Advances in Understanding Alzheimer's, Parkinson's, and Huntington's Diseases and Amyotrophic Lateral Sclerosis

Neurodegenerative diseases are, according to recent studies, one of the main causes of disability and death worldwide. Interest in molecular genetics has started to experience exponential growth thanks to numerous advancements in technology, shifts in the understanding of the disease as a phenomenon, and the change in the perspective regarding gene editing and the advantages of this action. The aim of this paper is to analyze the newest approaches in genetics and molecular sciences regarding four of the most important neurodegenerative disorders: Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. We intend through this review to focus on the newest treatment, diagnosis, and predictions regarding this large group of diseases, in order to obtain a more accurate analysis and to identify the emerging signs that could lead to a better outcome in order to increase both the quality and the life span of the patient. Moreover, this review could provide evidence of future possible novel therapies that target the specific genes and that could be useful to be taken into consideration when the classical approaches fail to shed light.

Demographic changes in a large motor neuron disease cohort in Portugal: a 27 year experience

Objective: Motor Neuron Diseases (MND) have a large clinical spectrum, being the most common amyotrophic lateral sclerosis (ALS) but there is significant clinical heterogeneity. Our goal was to investigate this heterogeneity and any potential changes during a long period. Methods: We performed a retrospective cohort study among a large Portuguese cohort of MND patients (n = 1550) and investigated changing patterns in clinical and demographic characteristics over the 27-year period of our database. With that aim, patients were divided into three 9-year groups according to the date of their first visit to our unit: P1, 1994-2002; P2, 2003-2011; P3, 2012-2020. Results: The overall cohort's clinical and demographic characteristics are consistent with clinical experience, but our findings point to gradual changes over time. Time pattern analysis revealed statistically significant differences in the distribution of clinical phenotypes, the average age of onset, diagnostic delay, the proportin of patients using respiratory support with noninvasive ventilation (NIV), time to NIV, and survival. Across time, in the overall cohort, we found an increasing age at onset (p = 0.029), a decrease of two months in diagnostic delay (p < 0.001) and a higher relative frequency of progressive muscular atrophy patients. For ALS patients with spinal onset, from P1 to P2, there was a more widespread (54.8% vs 69.4%, p = 0.005) and earlier (36.9 vs 27.2 months, p = 0.05) use of NIV and a noteworthy 13-month increase in median survival (p = 0.041). Conclusions: Our results probably reflect better comprehensive care, and they are relevant for future studies exploring the impact of new treatments on ALS patients.

Gender differences in clinical features at the initial examination of late-onset amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that mainly affects motor neurons in the brain and spinal cord. With the advent of aging societies, the proportion of elderly patients with ALS is expected to increase.

METHODS

We retrospectively compared the clinical characteristics at the initial examination of patients with onset of ALS at age 74 years or younger (early onset) and those aged 75 years or older at onset (late-onset) at a single regional ALS diagnostic center in Japan.

RESULTS

The phenotype of late-onset ALS differed between males and females, with late-onset females having more bulbar-onset ALS and significantly lower body mass index, late-onset males having more frequent bulbar and respiratory symptoms at the initial examination, and significantly lower forced vital capacity at the initial examination in both groups compared to early onset patients.

CONCLUSION

For late-onset patients, maintenance of skeletal muscle mass by early intervention for bulbar and respiratory symptoms may be useful for prolonging survival; however, a prospective analysis is warranted.

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.

The Use of Stem Cells as a Potential Treatment Method for Selected Neurodegenerative Diseases: Review

Stem cells have been the subject of research for years due to their enormous therapeutic potential. Most neurological diseases such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD) are incurable or very difficult to treat. Therefore new therapies are sought in which autologous stem cells are used. They are often the patient's only hope for recovery or slowing down the progress of the disease symptoms. The most important conclusions arise after analyzing the literature on the use of stem cells in neurodegenerative diseases. The effectiveness of MSC cell therapy has been confirmed in ALS and HD therapy. MSC cells slow down ALS progression and show early promising signs of efficacy. In HD, they reduced huntingtin (Htt) aggregation and stimulation of endogenous neurogenesis. MS therapy with hematopoietic stem cells (HSCs) inducted significant recalibration of pro-inflammatory and immunoregulatory components of the immune system. iPSC cells allow for accurate PD modeling. They are patient-specific and therefore minimize the risk of immune rejection and, in long-term observation, did not form any tumors in the brain. Extracellular vesicles derived from bone marrow mesenchymal stromal cells (BM-MSC-EVs) and Human adipose-derived stromal/stem cells (hASCs) cells are widely used to treat AD. Due to the reduction of Aβ42 deposits and increasing the survival of neurons, they improve memory and learning abilities. Despite many animal models and clinical trial studies, cell therapy still needs to be refined to increase its effectiveness in the human body.

Chitinase Signature in the Plasticity of Neurodegenerative Diseases

Several reports have pointed out that Chitinases are expressed and secreted by various cell types of central nervous system (CNS), including activated microglia and astrocytes. These cells play a key role in neuroinflammation and in the pathogenesis of many neurodegenerative disorders. Increased levels of Chitinases, in particular Chitotriosidase (CHIT-1) and chitinase-3-like protein 1 (CHI3L1), have been found increased in several neurodegenerative disorders. Although having important biological roles in inflammation, to date, the molecular mechanisms of Chitinase involvement in the pathogenesis of neurodegenerative disorders is not well-elucidated. Several studies showed that some Chitinases could be assumed as markers for diagnosis, prognosis, activity, and severity of a disease and therefore can be helpful in the choice of treatment. However, some studies showed controversial results. This review will discuss the potential of Chitinases in the pathogenesis of some neurodegenerative disorders, such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis, to understand their role as distinctive biomarkers of neuronal cell activity during neuroinflammatory processes. Knowledge of the role of Chitinases in neuronal cell activation could allow for the development of new methodologies for downregulating neuroinflammation and consequently for diminishing negative neurological disease outcomes.

Swimming against ALS: How to model disease in zebrafish for pathophysiological and behavioral studies

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease that leads to progressive disability and motor impairment. Existing therapies provide modest improvements in patient survival, raising a need for new treatments for ALS. Zebrafish is a promising model animal for translational and fundamental research in ALS - it is an experimentally tractable vertebrate, with high homology to humans and an ample experimental toolbox. These advantages allow high-throughput study of behavioral and pathophysiological phenotypes. The last decade saw an increased interest in modelling ALS in zebrafish, leading to the current abundance and variety of available methods and models. Additionally, the rise of gene editing techniques and toxin combination studies has created novel opportunities for ALS studies in zebrafish. In this review, we address the relevance of zebrafish as a model animal for ALS studies, the strategies for model induction and key phenotypical evaluation. Furthermore, we discuss established and emerging zebrafish models of ALS, analyzing their validity, including their potential for drug testing, and highlighting research opportunities in this area.

Distinct Plasma Immune Profile in ALS Implicates sTNFR-II in pAMPK/Leptin Homeostasis

Amyotrophic lateral sclerosis (ALS) is a clinically highly heterogeneous disease with a survival rate ranging from months to decades. Evidence suggests that a systemic deregulation of immune response may play a role and affect disease progression. Here, we measured 62 different immune/metabolic mediators in plasma of sporadic ALS (sALS) patients. We show that, at the protein level, the majority of immune mediators including a metabolic sensor, leptin, were significantly decreased in the plasma of sALS patients and in two animal models of the disease. Next, we found that a subset of patients with rapidly progressing ALS develop a distinct plasma assess immune–metabolic molecular signature characterized by a differential increase in soluble tumor necrosis factor receptor II (sTNF-RII) and chemokine (C-C motif) ligand 16 (CCL16) and further decrease in the levels of leptin, mostly dysregulated in male patients. Consistent with in vivo findings, exposure of human adipocytes to sALS plasma and/or sTNF-RII alone, induced a significant deregulation in leptin production/homeostasis and was associated with a robust increase in AMP-activated protein kinase (AMPK) phosphorylation. Conversely, treatment with an AMPK inhibitor restored leptin production in human adipocytes. Together, this study provides evidence of a distinct plasma immune profile in sALS which affects adipocyte function and leptin signaling. Furthermore, our results suggest that targeting the sTNF-RII/AMPK/leptin pathway in adipocytes may help restore assess immune–metabolic homeostasis in ALS.

Large-scale analyses of CAV1 and CAV2 suggest their expression is higher in post-mortem ALS brain tissue and affects survival

Introduction: Caveolin-1 and Caveolin-2 (CAV1 and CAV2) are proteins associated with intercellular neurotrophic signalling. There is converging evidence that CAV1 and CAV2 (CAV1/2) genes have a role in amyotrophic lateral sclerosis (ALS). Disease-associated variants have been identified within CAV1/2 enhancers, which reduce gene expression and lead to disruption of membrane lipid rafts. Methods: Using large ALS whole-genome sequencing and post-mortem RNA sequencing datasets (5,987 and 365 tissue samples, respectively), and iPSC-derived motor neurons from 55 individuals, we investigated the role of CAV1/2 expression and enhancer variants in the ALS phenotype. Results: We report a differential expression analysis between ALS cases and controls for CAV1 and CAV2 genes across various post-mortem brain tissues and three independent datasets. CAV1 and CAV2 expression was consistently higher in ALS patients compared to controls, with significant results across the primary motor cortex, lateral motor cortex, and cerebellum. We also identify increased survival among carriers of CAV1/2 enhancer mutations compared to non-carriers within Project MinE and slower progression as measured by the ALSFRS. Carriers showed a median increase in survival of 345 days. Discussion: These results add to an increasing body of evidence linking CAV1 and CAV2 genes to ALS. We propose that carriers of CAV1/2 enhancer mutations may be conceptualised as an ALS subtype who present a less severe ALS phenotype with a longer survival duration and slower progression. Upregulation of CAV1/2 genes in ALS cases may indicate a causal pathway or a compensatory mechanism. Given prior research supporting the beneficial role of CAV1/2 expression in ALS patients, we consider a compensatory mechanism to better fit the available evidence, although further investigation into the biological pathways associated with CAV1/2 is needed to support this conclusion.

Current State and Future Directions in the Diagnosis of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by loss of upper and lower motor neurons, resulting in progressive weakness of all voluntary muscles and eventual respiratory failure. Non-motor symptoms, such as cognitive and behavioral changes, frequently occur over the course of the disease. Considering its poor prognosis with a median survival time of 2 to 4 years and limited causal treatment options, an early diagnosis of ALS plays an essential role. In the past, diagnosis has primarily been determined by clinical findings supported by electrophysiological and laboratory measurements. To increase diagnostic accuracy, reduce diagnostic delay, optimize stratification in clinical trials and provide quantitative monitoring of disease progression and treatment responsivity, research on disease-specific and feasible fluid biomarkers, such as neurofilaments, has been intensely pursued. Advances in imaging techniques have additionally yielded diagnostic benefits. Growing perception and greater availability of genetic testing facilitate early identification of pathogenic ALS-related gene mutations, predictive testing and access to novel therapeutic agents in clinical trials addressing disease-modified therapies before the advent of the first clinical symptoms. Lately, personalized survival prediction models have been proposed to offer a more detailed disclosure of the prognosis for the patient. In this review, the established procedures and future directions in the diagnostics of ALS are summarized to serve as a practical guideline and to improve the diagnostic pathway of this burdensome disease.

[Gene Therapies in Motor Neuron Diseases ALS and SMA]

In the past, the diagnosis of motor neuron diseases such as amyotrophic lateral sclerosis (ALS) and 5q-associated spinal muscular atrophy (SMA) meant powerlessness in the face of seemingly untreatable diseases with severe motor-functional limitations and sometimes fatal courses. Recent advances in an understanding of the genetic causalities of these diseases, combined with success in the development of targeted gene therapy strategies, spell hope for effective, innovative therapeutic approaches, pioneering the ability to treat neurodegenerative diseases. While gene therapies have been approved for SMA since a few years, gene therapy research in ALS is still in clinical trials with encouraging results. This article provides an overview of the genetic background of ALS and SMA known to date and gene therapy approaches to them with a focus on therapy candidates that are in clinical trials or have already gained market approval.

Safety and Efficacy of Edaravone in Patients with Amyotrophic Lateral Sclerosis: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

The efficacy and safety of edaravone for the treatment of amyotrophic lateral sclerosis (ALS) remain unclear. The aim of this meta-analysis was to provide evidence-based medical guidance and advice for the clinical application of edaravone in the treatment of ALS.

METHODS

PubMed, Embase, Chinese Biomedical Literature Database (CBM), Cochrane Library and Web of Science were searched through 09 March 2022 for randomized controlled trials (RCTs) on the safety and efficacy of edaravone versus placebo during follow-up of patients with ALS. A summary of the outcome measures with GRADE was performed. This study was registered on PROSPERO (ID: CRD 42022319997).

RESULTS

Five RCTs with a total of 566 participants were included, and there was a significant difference (mean difference [MD] 1.33, 95% confidence interval [CI] 0.33-2.34; p = 0.009) in the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) score between the treatment and placebo groups. The edaravone group had an increased grip strength (MD 0.26, 95% CI 0.03-0.49; p = 0.03) and modified Norris Scale score (MD 2.81, 95% CI 1.18-4.43; p = 0.0007). However, there were no significant differences between groups for the change in forced vital capacity (FVC)% (MD 0.55, 95% CI - 3.15 to 4.24; p = 0.77), pinch strength (MD 0.05, 95% CI - 0.05 to 0.16; p = 0.33) or Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) score (MD - 4.76, 95% CI - 9.56 to 0.03; p = 0.05). The incidence of adverse events (AEs) (risk ratio [RR] 0.09, 95% CI 0.93-1.05; p = 0.65), serious adverse events (SAEs) (RR 0.72, 95% CI 0.52-1.00; p = 0.05) and the number of deaths (risk difference [RD] 0.00, 95% CI - 0.02 to 0.03; p = 0.83) were not statistically different from the placebo group. The quality of evidence was low only for SAEs, and the remaining outcome measures were of moderate quality.

CONCLUSIONS

Compared with placebo, edaravone may provide potential clinical benefits in the treatment of ALS and may not increase the number of AEs and deaths. However, due to the low-quality evidence of the included studies and the small sample size, more high-quality and high-standard research evidence is needed to confirm these results.

PROTOCOL REGISTRATION

This study was registered on PROSPERO (ID: CRD 42022319997).

Prospects for gene replacement therapies in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating and incurable neurodegenerative disease characterized by the progressive loss of upper and lower motor neurons. ALS causes death, usually within 2-5 years of diagnosis. Riluzole, the only drug currently approved in Europe for the treatment of this condition, offers only a modest benefit, increasing survival by 3 months on average. Recent advances in our understanding of causative or disease-modifying genetic variants and in the development of genetic therapy strategies present exciting new therapeutic opportunities for ALS. In addition, the approval of adeno-associated virus-mediated delivery of functional copies of the SMN1 gene to treat spinal muscular atrophy represents an important therapeutic milestone and demonstrates the potential of gene replacement therapies for motor neuron disorders. In this Review, we describe the current landscape of genetic therapies in ALS, highlighting achievements and critical challenges. In particular, we discuss opportunities for gene replacement therapy in subgroups of people with ALS, and we describe loss-of-function mutations that are known to contribute to the pathophysiology of ALS and could represent novel targets for gene replacement therapies.

Primary lateral sclerosis

Like motor neuron diseases (MNDs) refer to a constellation of primarily sporadic neurodegenerative diseases characterized by a progressive loss of upper and/or lower motor neurons. Primary lateral sclerosis (PLS) is considered a neurodegenerative disorder that is characterized by a gradually progressive course affecting the central motor systems, designated by the phrase "upper motor neurons." Despite significant development in neuroimaging, neurophysiology, and molecular biology, there is a growing consensus that PLS is of unknown etiology. Currently there is no disease-modifying treatment for PLS, or prospective randomized trials being carried out, partly due to the rarity of the disease and lack of significant understanding of the underlying pathophysiology. Consequently, the approach to treatment remains largely symptomatic. In this chapter we provide an overview of primary lateral sclerosis including clinical and electrodiagnostic considerations, differential diagnosis, updates in genetics and pathophysiology, and future directions for research.

Patient reported impact of symptoms in amyotrophic lateral sclerosis (PRISM-ALS): A national, cross-sectional study

BACKGROUND

As novel therapeutic interventions are being developed and tested in the amyotrophic lateral sclerosis (ALS) population, there is a need to better understand the symptoms and issues that have the greatest impact on the lives of individuals with ALS. We aimed to determine the frequency and relative importance of symptoms experienced by adults in a national ALS sample and to identify factors that are associated with the greatest disease burden in this population.

METHODS

We conducted 15 qualitative interviews of individuals with varied ALS phenotypes and analyzed 732 quotes regarding the symptomatic disease burden of ALS between August 2018 and March 2019. We subsequently conducted a national, cross-sectional study of 497 participants with ALS and ALS variants through the Centers for Disease Control and Prevention's (CDC) National ALS Registry between July 2019 and December 2019. Participants reported on the prevalence and relative importance of 189 symptomatic questions representing 17 symptomatic themes that were previously identified through qualitative interviews. Analysis was performed to determine how age, sex, education, employment, time since onset of symptoms, location of symptom onset, feeding tube status, breathing status and speech status relate to symptom and symptomatic theme prevalence.

FINDINGS

Symptomatic themes with the highest prevalence in our sample were an inability to do activities (93.8%), fatigue (92.6%), problems with hands or fingers (87.7%), limitations with mobility or walking (86.7%), and a decreased performance in social situations (85.7%). Participants identified inability to do activities and limitations with mobility or walking as having the greatest overall effect on their lives.

INTERPRETATION

Individuals with ALS experience a variety of symptoms that affect their lives. The prevalence and importance of these symptoms differ among the ALS population. The most prevalent and important symptoms offer potential targets for improvements in future therapeutic interventions.

FUNDING

Research funding was provided by ALS Association.

Age of Onset and Length of Survival of Queensland Patients with Amyotrophic Lateral Sclerosis: Details of Subjects with Early Onset and Subjects with Long Survival

INTRODUCTION

The aims of the study were to document the characteristics of amyotrophic lateral sclerosis (ALS) patients in Queensland, to examine factors influencing age of onset, and survival, and to study those with early-onset (<45 years) disease and those with long (>5 years) survival.

METHODS

We studied subjects seen at the ALS Clinic at the Royal Brisbane and Women's Hospital. We recorded sex, age of onset, region of onset, length of survival, presence of family history, type of disease, and evidence of cognitive involvement. We analysed the influence of these features on age of onset and survival. We analysed the features of patients with early onset of disease and patients with long survival.

RESULTS

There were 855 ALS patients (505 males) in the cohort. The age of onset was lower in males than females, in patients with a family history of ALS compared to those without, and in patients with spinal onset compared to bulbar onset. Early-onset disease was seen in 10% of patients, and had a greater proportion of males, spinal onset, and classical ALS phenotype compared to late-onset disease. Survival was shorter in females, in patients with bulbar onset, and in patients with classical ALS. Long survival was seen in 18% of patients. Patients with long survival had younger age of onset, greater proportion of males, spinal onset, and fewer patients with classical ALS.

CONCLUSION

Our study confirms that ALS is more prevalent in males and that spinal onset is more common than bulbar onset. Males have earlier onset but longer survival. We found that overall, patients with classical ALS have worse survival than ALS variants, but some patients who were considered to have classical ALS had long survival. This study confirms the similarity of ALS in our region to ALS in other geographical regions.

Multiple pathways of lipid dysregulation in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a rapidly progressing neurodegenerative disease characterized by the degeneration of motor neurons and loss of various muscular functions. Dyslipidaemia is prevalent in amyotrophic lateral sclerosis with aberrant changes mainly in cholesterol ester and triglyceride. Despite this, little is known about global lipid changes in amyotrophic lateral sclerosis or in relation to disease progression. The present study incorporated a longitudinal lipidomic analysis of amyotrophic lateral sclerosis serum with a comparison with healthy controls using advanced liquid chromatography-mass spectrometry. The results established that diglyceride, the precursor of triglyceride, was enriched the most, while ceramide was depleted the most in amyotrophic lateral sclerosis compared with controls, with the diglyceride species (18:1/18:1) correlating significantly to neurofilament light levels. The prenol lipid CoQ₈ was also decreased in amyotrophic lateral sclerosis and correlated to neurofilament light levels. Most interestingly, the phospholipid phosphatidylethanolamine and its three derivatives decreased with disease progression, in contrast to changes with normal ageing. Unsaturated lipids that are prone to lipid peroxidation were elevated with disease progression with increases in the formation of toxic lipid products. Furthermore, in vitro studies revealed that phosphatidylethanolamine synthesis modulated TARDBP expression in SH-SY5Y neuronal cells. Finally, diglyceride, cholesterol ester and ceramide were identified as potential lipid biomarkers for amyotrophic lateral sclerosis diagnosis and monitoring disease progression. In summary, this study represents a longitudinal lipidomics analysis of amyotrophic lateral sclerosis serum and has provided new insights into multiple pathways of lipid dysregulation in amyotrophic lateral sclerosis.

Development and validation of a dynamic risk prediction system for constipation in patients with amyotrophic lateral sclerosis

Introduction

Although constipation is a common non-motor symptom in patients with amyotrophic lateral sclerosis (ALS), it is poorly valued. Moreover, there is a bidirectional effect between constipation and neuropsychiatric and sleep disturbances. Thus, these symptoms are better treated simultaneously. Therefore, this study aimed to develop and validate a model for predicting the risk of constipation in ALS patients, to help clinicians identify and treat constipation early.

Methods

Data of 118 ALS admissions from an observational prospective cohort, registered between March 2017 and December 2021, were analyzed. Demographic data were obtained. Constipation was assessed using the Knowles-Eccersley-Scott Symptom Questionnaire. The severity of ALS was assessed using the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R). Anxiety and depressive symptoms were measured using the Hospital Anxiety and Depression Scale (HADS). The Pittsburgh Sleep Quality Index (PSQI) was used to assess patients' sleep status. The least absolute shrinkage and selection operator (LASSO) regression model was used to select factors and construct a nomogram. Nomogram model performance was evaluated using the area under the receiver operating characteristic curve (AUC), calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC). The model was internally validated using bootstrap validation in the current cohort.

Results

Age, family history of constipation, total ALSFRS-R score, site of onset, total PSQI score, and depressed, were identified as significant predictors of the risk of constipation in ALS patients. The prediction model was validated to have good accuracy (Hosmer-Lemeshow test: χ² = 11.11, P > 0.05) and discrimination (AUC = 0.856, 95% confidence interval: 0.784-0.928). DCA and CIC showed that the nomogram model had excellent clinical performance.

Conclusions

A web-based ALS constipation risk calculator with good predictive performance was constructed to identify patients at high risk of constipation and to allow early intervention in a clinical context.