Factors predicting survival in ALS: a multicenter Italian study

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.

Amyotrophic lateral sclerosis stratification: unveiling patterns with virome, inflammation, and metabolism molecules

Amyotrophic lateral sclerosis (ALS) is an untreatable and clinically heterogeneous condition primarily affecting motor neurons. The ongoing quest for reliable biomarkers that mirror the disease status and progression has led to investigations that extend beyond motor neurons' pathology, encompassing broader systemic factors such as metabolism, immunity, and the microbiome. Our study contributes to this effort by examining the potential role of microbiome-related components, including viral elements, such as torque tenovirus (TTV), and various inflammatory factors, in ALS. In our analysis of serum samples from 100 ALS patients and 34 healthy controls (HC), we evaluated 14 cytokines, TTV DNA load, and 18 free fatty acids (FFA). We found that the evaluated variables are effective in differentiating ALS patients from healthy controls. In addition, our research identifies four unique patient clusters, each characterized by distinct biological profiles. Intriguingly, no correlations were found with site of onset, sex, progression rate, phenotype, or C9ORF72 expansion. A remarkable aspect of our findings is the discovery of a gender-specific relationship between levels of 2-ethylhexanoic acid and patient survival. In addition to contributing to the growing body of evidence suggesting altered peripheral immune responses in ALS, our exploratory research underscores metabolic diversity challenging conventional clinical classifications. If our exploratory findings are validated by further research, they could significantly impact disease understanding and patient care customization. Identifying groups based on biological profiles might aid in clustering patients with varying responses to treatments.

Racial disparities in ALS diagnostic delay: a single center's experience and review of potential contributing factors

OBJECTIVE

Outcomes for amyotrophic lateral sclerosis (ALS) patients are improved with prompt diagnosis, earlier initiation of disease-modifying treatments, and participation in a multidisciplinary clinic. We studied diagnostic delay and disease severity at time of clinic presentation between Black and non-Hispanic Caucasian ALS patients.

METHODS

We performed a retrospective analysis of non-Hispanic Caucasian and Black ALS patients seen in the Virginia Commonwealth University Health System multidisciplinary ALS clinic between 2017 and 2023. Diagnostic delay, ALS Functional Rating Scale-Revised (ALSFRS-R) and upright forced vital capacity (FVC) scores at baseline appointment were collected. Patient's distance from clinic and affluency of residential neighborhood were evaluated.

RESULTS

We analyzed 172 non-Hispanic Caucasian and 33 Black ALS patients. Black patients had a 64% increase in diagnostic delay compared to non-Hispanic Caucasian patients. Black patients had a lower performance on ALSFRS-R (5.3 points, p < 0.001) and FVC (17.9 percentage points p < 0.001) at time of first clinic visit. Black patients lived closer to clinic, with higher proportion living in the city of Richmond, but in less affluent areas with lower median house income ($55,300 ± 22,600 vs $69,900 ± 23,700).

DISCUSSION

Our findings demonstrate a large racial difference in ALS diagnostic delay, and greater disease severity and lower respiratory function at time of diagnosis for Black ALS patients. Delay in diagnosis prolongs access to disease-modifying therapies, multidisciplinary care, durable medical equipment, and respiratory and nutritional support. Potential sources of these racial disparities include providers' implicit bias and structural racism.

SerpinA1 levels in amyotrophic lateral sclerosis patients: An exploratory study

BACKGROUND

SerpinA1, a serine protease inhibitor, is involved in the modulation of microglial-mediated inflammation in neurodegenerative diseases. We explored SerpinA1 levels in cerebrospinal fluid (CSF) and serum of amyotrophic lateral sclerosis (ALS) patients to understand its potential role in the pathogenesis of the disease.

METHODS

SerpinA1, neurofilament light (NfL) and heavy (NfH) chain, and chitinase-3-like protein-1 (CHI3L1) were determined in CSF and serum of ALS patients (n = 110) and healthy controls (n = 10) (automated next-generation ELISA), and correlated with clinical parameters, after identifying three classes of progressors (fast, intermediate, slow). Biomarker levels were analyzed for diagnostic power and association with progression and survival.

RESULTS

SerpinA1serum was significantly decreased in ALS (median: 1032 μg/mL) compared with controls (1343 μg/mL) (p = 0.02). SerpinA1CSF was elevated only in fast progressors (8.6 μg/mL) compared with slow (4.43 μg/mL, p = 0.01) and intermediate (4.42 μg/mL, p = 0.03) progressors. Moreover, SerpinA1CSF correlated with neurofilament and CHI3L1 levels in CSF. Contrarily to SerpinA1CSF , neurofilament and CHI3L1 concentrations in CSF correlated with measures of disease progression in ALS, while SerpinA1serum mildly related with time to generalization (rho = 0.20, p = 0.04). In multivariate analysis, the ratio between serum and CSF SerpinA1 (SerpinA1 ratio) and NfHCSF were independently associated with survival.

CONCLUSIONS

Higher SerpinA1CSF levels are found in fast progressors, suggesting SerpinA1 is a component of the neuroinflammatory mechanisms acting upon fast-progressing forms of ALS. Both neurofilaments or CHI3L1CSF levels outperformed SerpinA1 at predicting disease progression rate in our cohort, and so the prognostic value of SerpinA1 alone as a measure remains inconclusive.

Predictors for progression in amyotrophic lateral sclerosis associated to SOD1 mutation: insight from two population-based registries

BACKGROUND

Uncovering distinct features and trajectories of amyotrophic lateral sclerosis (ALS) associated with SOD1 mutations (SOD1-ALS) can provide valuable insights for patient' counseling and stratification for trials, and interventions timing. Our study aims to pinpoint distinct clinical characteristics of SOD1-ALS by delving into genotype-phenotype correlations and factors that potentially impact disease progression.

METHODS

This is a retrospective observational study of a SOD1-ALS cohort from two Italian registers situated in the regions of Emilia-Romagna, Piedmont and Valle d'Aosta.

RESULTS

Out of 2204 genotyped ALS patients, 2.5% carried SOD1 mutations, with a M:F ratio of 0.83. SOD1-ALS patients were younger, and more frequently reported a family history of ALS and/or FTD. SOD1-ALS had a longer survival compared to patients without ALS-associated gene mutations. However, here was considerable variability in survival across distinct SOD1 mutations, with an average survival of less than a year for the L39V, G42S, G73S, D91N mutations. Among SOD1-ALS, multivariate analysis showed that, alongside established clinical prognostic factors such as advanced age at onset and high progression rate at diagnosis, mutations located in exon 2 or within highly conserved gene positions predicted worse survival. Conversely, among comorbidities, cancer history was independently associated with longer survival.

INTERPRETATION

Within the context of an overall slower disease, SOD1-ALS exhibits some degree of heterogeneity linked to the considerable genetic diversity arising from the multitude of potential mutations sites and specific clinical prognostic factors, including cancer history. Revealing the factors that modulate the phenotypic heterogeneity of SOD1-ALS could prove advantageous in improving the efficacy of upcoming therapeutic approaches.

Genetic Modifiers of Age at Onset for Amyotrophic Lateral Sclerosis: A Genome-Wide Association Study

OBJECTIVE

Age at onset (AAO) is an essential clinical feature associated with disease progression and mortality in amyotrophic lateral sclerosis (ALS). Identification of genetic variants and environmental risk factors influencing AAO of ALS could help better understand the disease's biological mechanism and provide clinical guidance. However, most genetic studies focused on the risk of ALS, while the genetic background of AAO is less explored. This study aimed to identify genetic and environmental determinants for AAO of ALS.

METHODS

We performed a genome-wide association analysis using a Cox proportional hazards model on AAO of ALS in 10,068 patients. We further conducted colocalization analysis and in-vitro functional exploration for the target variants, as well as Mendelian randomization analysis to identify risk factors influencing AAO of ALS.

RESULTS

The total heritability of AAO of ALS was ~0.16 (standard error [SE] = 0.03). One novel locus rs2046243 (CTIF) was significantly associated with earlier AAO by ~1.29 years (p = 1.68E-08, beta = 0.10, SE = 0.02). Functional exploration suggested this variant was associated with increased expression of CTIF in multiple tissues including the brain. Colocalization analysis detected a colocalization signal at the locus between AAO of ALS and expression of CTIF. Causal inference indicated higher education level was associated with later AAO.

INTERPRETATION

These findings improve the current knowledge of the genetic and environmental etiology of AAO of ALS, and provide a novel target CTIF for further research on ALS pathogenesis and potential therapeutic options to delay the disease onset. ANN NEUROL 2023;94:933-941.

Diagnostic delay in amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal neurodegenerative disease, and the time from symptom onset to diagnosis remains long. With the advent of disease-modifying treatments, the need to identify and diagnose ALS in a timely fashion has never been greater.

METHODS

We reviewed the literature to define the severity of ALS diagnostic delay, the various factors that contribute to this delay (including patient and physician factors), and the role that site of symptom onset plays in a patient's diagnostic journey.

RESULTS

Diagnostic delay is influenced by general practitioners' lack of recognition of ALS due to disease rarity and heterogenous presentations. As a result, patients are referred to non-neurologists, have unnecessary diagnostic testing, and may ultimately be misdiagnosed. Patient factors include their illness behavior-which impacts diagnostic delay-and their site of symptom onset. Limb-onset patients have the greatest diagnostic delay because they are frequently misdiagnosed with degenerative spine disease or peripheral neuropathy.

CONCLUSION

Prompt ALS diagnosis results in more effective clinical management, with earlier access to disease-modifying therapies, multidisciplinary care, and, if desired, clinical trial involvement. Due to lack of commercially available ALS biomarkers, alternative strategies to identify and triage patients who likely have ALS must be employed. Several diagnostic tools have been developed to encourage general practitioners to consider ALS and make an urgent referral to ALS specialists, bypassing unnecessary referrals to non-neurologists and unnecessary diagnostic workup.

Effect of mesenchymal stromal cell transplantation on long-term survival in amyotrophic lateral sclerosis

BACKGROUND AIMS

Thanks to their immunomodulatory, tissue-protective and regenerative properties, mesenchymal stromal cells (MSCs) are a promising approach for amyotrophic lateral sclerosis (ALS); however, trials are limited and few follow-up studies have been published. This post-hoc analysis aims to describe the potential long-term effects of MSCs in ALS, analyzing data from two phase 1 clinical trials in ALS patients conducted by our group in 2002 and 2006.

METHODS

We conducted two consecutive phase 1 prospective, open, pilot clinical trials, enrolling a total of 19 ALS patients. We followed patients for the duration of the disease. For each patient, we used the European Network to Cure ALS (ENCALS) survival prediction model to retrospectively calculate the expected survival at diagnosis. We then compared the predicted disease duration with the observed survival, analyzing patients at a single-patient level.

RESULTS

Using the ENCALS model, we predicted short survival in one patient, intermediate survival in three patients, long survival in three patients and very long survival in 12 patients. The difference between predicted and observed survival for the whole group was significant and demonstrated a mean predicted survival of 70.79 months (standard deviation [SD], 27.53) and a mean observed survival of 118.8 months (SD, 89.26) (P = 0.016). Based on the monthly ALS Functional Rating Scale-Revised progression rate (median, 0.64/month), we considered 10 of 19 patients slow progressors and nine of 19 patients fast progressors. Of the slow progressors, eight of 10 (80%) had significantly increased disease duration compared with predicted, and only two (20%) had decreased estimated disease duration. By contrast, five of nine (55%) fast progressors had increased disease duration, whereas four (45%) had decreased disease duration. To date, four patients are still alive.

CONCLUSIONS

The current study represents the first very long-term analysis of survival as an effect of MSC focal transplantation in the central nervous system of ALS patients, demonstrating that MSC transplantation could potentially slow down ALS progression and improve survival. Due to the interindividual variability in clinical course, at the current state of our knowledge, we cannot generalize the results, but these data provide new insights for planning the next generation of efficacy MSC clinical trials in ALS.

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.

Serum chloride as a respiratory failure marker in amyotrophic lateral sclerosis

Respiratory failure is the most common cause of death in patients with amyotrophic lateral sclerosis (ALS) and occurs with great variability among patients according to different phenotypic features. Early predictors of respiratory failure in ALS are important to start non-invasive ventilation (NIV). Venous serum chloride values correlate with carbonate (HCO3-) blood levels and reflect metabolic compensation of respiratory acidosis. Despite its wide availability and low cost, few data on serum chloride as a prognostic marker exist in ALS literature. In the present study, we evaluated serum chloride values at diagnosis as prognostic biomarkers for overall survival and NIV adaptation in a retrospective center-based cohort of ALS patients. We collected all ALS patients with serum chloride assessment at diagnosis, identified through the Piemonte and Valle d'Aosta Register for ALS, evaluating the correlations among serum chloride, clinical features, and other serum biomarkers. Thereafter, time-to-event analysis was modeled to predict overall survival and NIV start. We found a significant correlation between serum chloride and inflammatory status markers, serum sodium, forced vital capacity (FVC), ALS functional rating scale-revised (ALSFRS-R) item 10 and 11, age at diagnosis, and weight loss. Time-to-event analysis confirmed both in univariate analysis and after multiple confounders' adjustment that serum chloride value at diagnosis significantly influenced survival and time to NIV start. According to our analysis, based on a large ALS cohort, we found that serum chloride analyzed at diagnosis is a low-cost marker of impending respiratory decompensation. In our opinion, it should be added among the serum prognostic biomarkers that are able to stratify patients into different prognostic categories even when performed in the early phases of the disease.

Symptoms timeline and outcomes in amyotrophic lateral sclerosis using artificial intelligence

Amyotrophic lateral sclerosis (ALS) is a fatal, neurodegenerative motor neuron disease. Although an early diagnosis is crucial to provide adequate care and improve survival, patients with ALS experience a significant diagnostic delay. This study aimed to use real-world data to describe the clinical profile and timing between symptom onset, diagnosis, and relevant outcomes in ALS. Retrospective and multicenter study in 5 representative hospitals and Primary Care services in the SESCAM Healthcare Network (Castilla-La Mancha, Spain). Using Natural Language Processing (NLP), the clinical information in electronic health records of all patients with ALS was extracted between January 2014 and December 2018. From a source population of all individuals attended in the participating hospitals, 250 ALS patients were identified (61.6% male, mean age 64.7 years). Of these, 64% had spinal and 36% bulbar ALS. For most defining symptoms, including dyspnea, dysarthria, dysphagia and fasciculations, the overall diagnostic delay from symptom onset was 11 (6-18) months. Prior to diagnosis, only 38.8% of patients had visited the neurologist. In a median post-diagnosis follow-up of 25 months, 52% underwent gastrostomy, 64% non-invasive ventilation, 16.4% tracheostomy, and 87.6% riluzole treatment; these were more commonly reported (all Ps < 0.05) and showed greater probability of occurrence (all Ps < 0.03) in bulbar ALS. Our results highlight the diagnostic delay in ALS and revealed differences in the clinical characteristics and occurrence of major disease-specific events across ALS subtypes. NLP holds great promise for its application in the wider context of rare neurological diseases.

Molecular subtypes of ALS are associated with differences in patient prognosis

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease with poorly understood clinical heterogeneity, underscored by significant differences in patient age at onset, symptom progression, therapeutic response, disease duration, and comorbidity presentation. We perform a patient stratification analysis to better understand the variability in ALS pathology, utilizing postmortem frontal and motor cortex transcriptomes derived from 208 patients. Building on the emerging role of transposable element (TE) expression in ALS, we consider locus-specific TEs as distinct molecular features during stratification. Here, we identify three unique molecular subtypes in this ALS cohort, with significant differences in patient survival. These results suggest independent disease mechanisms drive some of the clinical heterogeneity in ALS.

Potential Applications for Growth Hormone Secretagogues Treatment of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) arises from neuronal death due to complex interactions of genetic, molecular, and environmental factors. Currently, only two drugs, riluzole and edaravone, have been approved to slow the progression of this disease. However, ghrelin and other ligands of the GHS-R1a receptor have demonstrated interesting neuroprotective activities that could be exploited in this pathology. Ghrelin, a 28-amino acid hormone, primarily synthesized and secreted by oxyntic cells in the stomach wall, binds to the pituitary GHS-R1a and stimulates GH secretion; in addition, ghrelin is endowed with multiple extra endocrine bioactivities. Native ghrelin requires esterification with octanoic acid for binding to the GHS-R1a receptor; however, this esterified form is very labile and represents less than 10% of circulating ghrelin. A large number of synthetic compounds, the growth hormone secretagogues (GHS) encompassing short peptides, peptoids, and non-peptidic moieties, are capable of mimicking several biological activities of ghrelin, including stimulation of GH release, appetite, and elevation of blood IGF-I levels. GHS have demonstrated neuroprotective and anticonvulsant effects in experimental models of pathologies both in vitro and in vivo. To illustrate, some GHS, currently under evaluation by regulatory agencies for the treatment of human cachexia, have a good safety profile and are safe for human use. Collectively, evidence suggests that ghrelin and cognate GHS may constitute potential therapies for ALS.

A phase 2, double-blind, placebo-controlled trial of a valproate/lithium combination in ALS patients

BACKGROUND

Few treatments are currently available for amyotrophic lateral sclerosis (ALS). A combination of lithium carbonate and valproic acid (VPA-Li) was shown to inhibit motor neuron death and delay disease progression.

METHODS

Outpatients with a typical ALS presentation were enrolled in a randomized, placebo-controlled trial to assess the efficacy of orally administered VPA-Li. Changes in a functional scale score (ALSFRS-R) and survival rate were chosen as primary outcome variables. Secondary outcome variables included BMI, respiratory monitoring, quality of life, and a global impression of the treatment.

RESULTS

Out of 42 patients enrolled, 20 individuals receiving VPA-Li and 18 on placebo treatment were included in the final analysis. Forty-five percent of patients receiving VPA-Li completed the trial, whereas only 22.22% of patients in the placebo group attended the final visit 18 months later (P = 0.09). Major changes in the ALSFRS-R score were observed, including a decrease of 1.195 points/month in the placebo group (95% CI: 0.7869-1.6031) and of 0.5085 under VPA-Li treatment (95% CI: 0.2288-0.7882) between months 6 and 14. Adverse events included bad mouth taste, constipation, and anorexia. Survival rate, body weight, and quality of life were positive outcomes by the end of the trial despite a high sample reduction, especially in the placebo group. The inclusion of 212 subjects in each group would confirm these differences.

CONCLUSIONS

Combined VPA-Li treatment associated with slower ALS progression and better secondary outcomes. This dual treatment overcame the futility threshold and merits further investigation in ALS.

Proposals from a French expert panel for respiratory care in ALS patients

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive diaphragm weakness and deteriorating lung function. Bulbar involvement and cough weakness contribute to respiratory morbidity and mortality. ALS-related respiratory failure significantly affects quality of life and is the leading cause of death. Non-invasive ventilation (NIV), which is the main recognized treatment for alleviating the symptoms of respiratory failure, prolongs survival and improves quality of life. However, the optimal timing for the initiation of NIV is still a matter of debate. NIV is a complex intervention. Multiple factors influence the efficacy of NIV and patient adherence. The aim of this work was to develop practical evidence-based advices to standardize the respiratory care of ALS patients in French tertiary care centres.

METHODS

For each proposal, a French expert panel systematically searched an indexed bibliography and prepared a written literature review that was then shared and discussed. A combined draft was prepared by the chairman for further discussion. All of the proposals were unanimously approved by the expert panel.

RESULTS

The French expert panel updated the criteria for initiating NIV in ALS patients. The most recent criteria were established in 2005. Practical advice for NIV initiation were included and the value of each tool available for NIV monitoring was reviewed. A strategy to optimize NIV parameters was suggested. Revisions were also suggested for the use of mechanically assisted cough devices in ALS patients.

CONCLUSION

Our French expert panel proposes an evidence-based review to update the respiratory care recommendations for ALS patients in daily practice.

Predicting functional impairment trajectories in amyotrophic lateral sclerosis: a probabilistic, multifactorial model of disease progression

Objective

To employ Artificial Intelligence to model, predict and simulate the amyotrophic lateral sclerosis (ALS) progression over time in terms of variable interactions, functional impairments, and survival.

Methods

We employed demographic and clinical variables, including functional scores and the utilisation of support interventions, of 3940 ALS patients from four Italian and two Israeli registers to develop a new approach based on Dynamic Bayesian Networks (DBNs) that models the ALS evolution over time, in two distinct scenarios of variable availability. The method allows to simulate patients’ disease trajectories and predict the probability of functional impairment and survival at different time points.

Results

DBNs explicitly represent the relationships between the variables and the pathways along which they influence the disease progression. Several notable inter-dependencies were identified and validated by comparison with literature. Moreover, the implemented tool allows the assessment of the effect of different markers on the disease course, reproducing the probabilistically expected clinical progressions. The tool shows high concordance in terms of predicted and real prognosis, assessed as time to functional impairments and survival (integral of the AU-ROC in the first 36 months between 0.80–0.93 and 0.84–0.89 for the two scenarios, respectively).

Conclusions

Provided only with measurements commonly collected during the first visit, our models can predict time to the loss of independence in walking, breathing, swallowing, communicating, and survival and it can be used to generate in silico patient cohorts with specific characteristics. Our tool provides a comprehensive framework to support physicians in treatment planning and clinical decision-making.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11022-0.

Phosphorylated TDP-43 aggregates in peripheral motor nerves of patients with amyotrophic lateral sclerosis

Phosphorylated TDP-43 (pTDP-43) aggregates in the cytoplasm of motor neurons and neuroglia in the brain are one of the pathological hallmarks of amyotrophic lateral sclerosis. Although the axons exceed the total volume of motor neuron soma by several orders of magnitude, systematic studies investigating the presence and distribution of pTDP-43 aggregates within motor nerves are still lacking. The aim of this study is to define the TDP-43/pTDP-43 pathology in diagnostic motor nerve biopsies performed on a large cohort of patients presenting with a lower motor neuron syndrome and to assess whether this might be a discriminating tissue biomarker for amyotrophic lateral sclerosis and non-amyotrophic lateral sclerosis cases.

We retrospectively evaluated 102 lower motor neuron syndrome patients referred to our centre for a diagnostic motor nerve biopsy. Histopathological criteria of motor neuron disease and motor neuropathy were applied by two independent evaluators, who were blind to clinical data. TDP-43 and pTDP-43 were evaluated by immunohistochemistry, and results compared to final clinical diagnosis.

We detected significant differences between amyotrophic lateral sclerosis and non-amyotrophic lateral sclerosis cases in pTDP-43 expression in myelinated fibres: axonal accumulation was detected in 98.2% of patients with amyotrophic lateral sclerosis versus 30.4% of non-amyotrophic lateral sclerosis samples (P < 0.0001), while concomitant positive staining in Schwan cell cytoplasm was found in 70.2% of patients with amyotrophic lateral sclerosis versus 17.4% of patients who did not have amyotrophic lateral sclerosis (P < 0.001). Importantly, we were also able to detect pTDP-43 aggregates in amyotrophic lateral sclerosis cases displaying normal features at standard histopathological analysis.

Our findings demonstrated that a specific pTDP-43 signature is present in the peripheral nervous system of patients with amyotrophic lateral sclerosis, and could be exploited as a specific, accessible tissue biomarker. The detection of pTDP-43 aggregates within motor nerves of living patients with amyotrophic lateral sclerosis, occurring before axonal degeneration, suggests that this is an early event that may contribute to amyotrophic lateral sclerosis pathogenesis.

Amyotrophic Lateral Sclerosis-Frontotemporal Dementia: Shared and Divergent Neural Correlates Across the Clinical Spectrum

BACKGROUND AND OBJECTIVES

A significant overlap between amyotrophic lateral sclerosis (ALS) and behavioral variant of frontotemporal dementia (bvFTD) has been observed at clinical, genetic, and pathologic levels. Within this continuum of presentations, the presence of mild cognitive or behavioral symptoms in patients with ALS has been consistently reported, although it is unclear whether this is to be considered a distinct phenotype or rather a natural evolution of ALS. Here, we used mathematical modeling of MRI connectomic data to decipher common and divergent neural correlates across the ALS-frontotemporal dementia (FTD) spectrum.

METHODS

We included 83 patients with ALS, 35 patients with bvFTD, and 61 healthy controls, who underwent clinical, cognitive, and MRI assessments. Patients with ALS were classified according to the revised Strong criteria into 54 ALS with only motor deficits (ALS-cn), 21 ALS with cognitive or behavioral involvement (ALS-ci/bi), and 8 ALS with bvFTD (ALS-FTD). First, we assessed the functional and structural connectivity patterns across the ALS-FTD spectrum. Second, we investigated whether and where MRI connectivity alterations of patients with ALS with any degree of cognitive impairment (i.e., ALS-ci/bi and ALS-FTD) resembled more the pattern of damage of one (ALS-cn) or the other end (bvFTD) of the spectrum, moving from group-level to single-subject analysis.

RESULTS

As compared with controls, extensive structural and functional disruption of the frontotemporal and parietal networks characterized bvFTD (bvFTD-like pattern), while a more focal structural damage within the sensorimotor-basal ganglia areas characterized ALS-cn (ALS-cn-like pattern). ALS-ci/bi patients demonstrated an ALS-cn-like pattern of structural damage, diverging from ALS-cn with similar motor impairment for the presence of enhanced functional connectivity within sensorimotor areas and decreased functional connectivity within the bvFTD-like pattern. On the other hand, patients with ALS-FTD resembled both structurally and functionally the bvFTD-like pattern of damage with, in addition, the structural ALS-cn-like damage in the motor areas.

DISCUSSION

Our findings suggest a maladaptive role of functional rearrangements in ALS-ci/bi concomitantly with similar structural alterations compared to ALS-cn, supporting the hypothesis that ALS-ci/bi might be considered as a phenotypic variant of ALS, rather than a consequence of disease worsening.

The hypometabolic state: a good predictor of a better prognosis in amyotrophic lateral sclerosis

BACKGROUND

Malnutrition and weight loss are negative prognostic factors for survival in patients with amyotrophic lateral sclerosis (ALS). However, energy expenditure at rest (REE) is still not included in clinical practice, and no data are available concerning hypometabolic state in ALS.

OBJECTIVE

To evaluate in a referral cohort of patients with ALS the prevalence of hypometabolic state as compared with normometabolic and hypermetabolic states, and to correlate it with clinical phenotype, rate of progression and survival.

DESIGN

We conducted a retrospective study examining REE measured by indirect calorimetry in patients with ALS referred to Milan, Limoges and Tours referral centres between January 2011 and December 2017. Hypometabolism and hypermetabolism states were defined when REE difference between measured and predictive values was ≤-10% and ≥10%, respectively. We evaluated the relationship between these metabolic alterations and measures of body composition, clinical characteristics and survival.

RESULTS

Eight hundred forty-seven patients with ALS were recruited. The median age at onset was 63.79 years (IQR 55.00-71.17). The male/female ratio was 1.26 (M/F: 472/375). Ten per cent of patients with ALS were hypometabolic whereas 40% were hypermetabolic. Hypometabolism was significantly associated with later need for gastrostomy, non-invasive ventilation and tracheostomy placement. Furthermore, hypometabolic patients with ALS significantly outlived normometabolic (HR=1.901 (95% CI 1.080 to 3.345), p=0.0259) and hypermetabolic (HR=2.138 (95% CI 1.154 to 3.958), p=0.0157) patients.

CONCLUSION

Hypometabolism in ALS is not uncommon and is associated with slower disease progression and better survival than normometabolic and hypermetabolic subjects. Indirect calorimetry should be performed at least at time of diagnosis because alterations in metabolism are correlated with prognosis.

Trends in survival of ALS from a population-based registry

Objective: To assess survival of ALS patients in general and in selected demographic and clinical subgroups comparing two periods (1998-2000 vs. 2008-2010). Methods: Newly diagnosed adults resident of Lombardy, Northern Italy from a population-based registry were included. Data were collected on age at diagnosis, sex, site of onset, diagnostic delay, and El-Escorial diagnostic category. Patients were followed until death or last observation. Survival was evaluated using Kaplan-Meier curves and Cox's proportional hazards models. Results: In 2008-2010 (267 patients), median survival was 2.4 years and 1-year, 2-year, 3-year and 5-year survival rates were 79%, 56%, 41% and 24%. Longer survival was associated with male sex, younger age, spinal onset, and longer diagnostic delay. Multivariable analysis confirmed higher death in 65-69yr (HR 2.8; 95% CI 1.4-5.6), 70-74yr (HR 3.2; 95% CI 1.6-6.3) and 75 + yr (HR 6.9; 95% CI 3.5-13.8) categories, compared to ≤49yr, in females (HR 1.4; 95% CI 1.02-1.8), compared to males, and in patients diagnosed after 6-12 months (HR 1.9; 95% CI 1.4-2.7), compared with longer diagnostic delay. In 1998-2000 (235 patients), median survival was 2.2 years. The 1-year, 2-year, 3-year and 5-year survival rates were 77%, 53%, 38% and 20%. When adjusting for demographic and clinical variables, the HR for death in 2008-2010 versus 1998-2000 was 0.80 (95% CI 0.66-0.98). A significant increase of survival in 2008-2010 was found only in patients aged 50-59yr and 70-74yr at diagnosis. Conclusions: Survival of ALS has increased over time in the last decades, especially in middle aged and elderly patients. The benefits of comprehensive care in selected age groups might explain our findings.

Blood-Brain Barrier Disruption Is Not Associated With Disease Aggressiveness in Amyotrophic Lateral Sclerosis

The pathogenesis of the fatal neurodegenerative condition amyotrophic lateral sclerosis (ALS) remains to be fully understood. Blood–brain barrier damage (BBBD) has been implicated as an exacerbating factor in several neurodegenerative conditions, including ALS. Therefore, this cross-sectional study used the novel D50 progression model to assess the clinical relevance of BBBD within a cohort of individuals with either ALS (n = 160) or ALS mimicking conditions (n = 31). Routine laboratory parameters in cerebrospinal fluid (CSF) and blood were measured, and the ratio of CSF to serum albumin levels (Qalb) was used as a proxy measure of BBBD. In the univariate analyses, Qalb levels correlated weakly with disease aggressiveness (as indicated by individual D50 values) and physical function (as measured by ALS Functional Rating Scale). However, after adjustment for cofactors in the elastic net regularization, only having limb-onset disease was associated with BBBD. The results reported here emphasize the clinical heterogeneity of ALS and the need for additional longitudinal and multi-modal studies to fully clarify the extent and effect of BBBD in ALS.

Noninvasive Ventilation Use Is Associated with Better Survival in Amyotrophic Lateral Sclerosis

Rationale: Noninvasive ventilation (NIV) is standard of care in amyotrophic lateral sclerosis (ALS), yet few data exist regarding its benefits.Objectives: We sought to identify whether the use of NIV was associated with survival in ALS.Methods: This was a single-center retrospective cohort study of 452 patients with ALS seen between 2006 and 2015. We matched one or more NIV subjects (prescribed NIV) to non-NIV subjects (never prescribed NIV) without replacement. The outcome was time from NIV prescription date (NIV subjects) or matched date (non-NIV subjects) until death. We performed a multivariable Cox proportional hazards model with NIV hourly usage as a time-varying covariate and stratified by matched groups.Results: After creating 180 matched groups and adjusting for age, body mass index, ALS Functional Rating Scale Revised dyspnea score, and hourly NIV use, NIV was associated with a 26% reduction in the rate of death compared with non-NIV subjects (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.57-0.98; P = 0.04). Among those with limb-onset ALS, NIV subjects had a 37% lower rate of death compared with non-NIV subjects (HR, 0.63; 95% CI, 0.45-0.87; P = 0.006). Among NIV subjects, we found that NIV use for an average of ≥4 h/d was associated with improved survival.Conclusions: NIV use was associated with significantly better survival in ALS after matching and adjusting for confounders. Increasing duration of daily NIV use was associated with longer survival. Randomized clinical trials should be performed to identify ideal thresholds for improving survival and optimizing adherence in ALS.

Mutation Screening of the GLE1 Gene in a Large Chinese Cohort of Amyotrophic Lateral Sclerosis Patients

Amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative disease involving the upper and lower motor neurons of the spinal cord, brainstem, and cerebral cortex. At least 30 genes have been implicated in familial ALS (fALS) and sporadic ALS (sALS). Kaneb et al. (2015) first carried out a large-scale sequencing study in ALS patients and identified two loss-of-function (LOF) variants in the GLE1 gene. The LOF mutation-induced disruption of RNA metabolism through the haploinsufficiency mechanism is implicated in ALS pathogenesis. A total of 628 ALS patients and 522 individuals without neurodegenerative disorders were enrolled in this study to explore the GLE1 gene contribution to ALS in the Chinese population. All 16 exons and the flanking intron of GLE1 were screened by Sanger sequencing. In total, we identified seven rare GLE1 coding variants, including one novel nonsense mutation and six rare missense mutations in 628 ALS patients. The frequency of GLE1 LOF mutations was 0.16% (1/628) among Chinese sALS patients, implying that it is an uncommon genetic determinant of ALS in Chinese patients. Additionally, the rare missense variants in the hCG1-binding domain of GLE1 impairing the distribution of the hGle1B isoform at the nuclear pore complex (NPC) region may be involved in the pathogenesis of ALS.

Cognitive reserve in amyotrophic lateral sclerosis (ALS): a population-based longitudinal study

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is often associated with cognitive and/or behavioural impairment. Cognitive reserve (CR) may play a protective role in offsetting cognitive impairment. This study examined the relationship between CR and longitudinal change in cognition in an Irish ALS cohort.

METHODS

Longitudinal neuropsychological assessment was carried out on 189 patients over 16 months using the Edinburgh cognitive and behavioural ALS screen (ECAS) and an additional battery of neuropsychological tests. CR was measured by combining education, occupation and physical activity data. Joint longitudinal and time-to-event models were fitted to investigate the associations between CR, performance at baseline and decline over time while controlling for non-random drop-out.

RESULTS

CR was a significant predictor of baseline neuropsychological performance, with high CR patients performing better than those with medium or low CR. Better cognitive performance in high CR individuals was maintained longitudinally for ECAS, social cognition, executive functioning and confrontational naming. Patients displayed little cognitive decline over the course of the study, despite controlling for non-random drop-out.

CONCLUSIONS

These findings suggest that CR plays a role in the presentation of cognitive impairment at diagnosis but is not protective against cognitive decline. However, further research is needed to examine the interaction between CR and other objective correlates of cognitive impairment in ALS.

Respiratory parameters on diagnostic sleep studies predict survival in patients with amyotrophic lateral sclerosis

OBJECTIVE

In amyotrophic lateral sclerosis (ALS), respiratory muscle involvement and sleep-disordered breathing relate to worse prognosis. The present study investigated whether respiratory outcomes on first-ever sleep studies predict survival in patients with ALS, specifically taking into account subsequent initiation of non-invasive ventilation (NIV).

METHODS

From patients with ALS, baseline sleep study records, transcutaneous capnometry, early morning blood gas analysis, survival data and clinical disease characteristics were retrospectively analyzed. Patients were stratified according to whether enduring NIV was consecutively established ("NIV(+)") or not ("NIV(-)").

RESULTS

Among the study cohort (n = 158, 72 female, 51 with bulbar onset ALS, 105 deceased) sleep-disordered breathing was present at baseline evaluation in 97 patients. Early morning base excess (EMBE) > 2 mmol/l predicted nocturnal hypercapnia. Ninety-five patients were NIV(+) and 63 were NIV(-). Survival from baseline sleep studies was significantly reduced in NIV(-) but not in NIV(+) patients with nocturnal CO₂ tension ≥ 50 mmHg, apnea hypopnea index ≥ 5/h, and EMBE > 2 mmol/l. Hazard ratio for EMBE > 2 mmol/l was increased in NIV(-) patients only, and EMBE independently predicted survival in both NIV(-) and NIV(+) patients. Furthermore, EMBE on baseline sleep studies was the only predictor for survival from symptom onset, and hazard ratio for shorter survival was markedly higher in the NIV(-) than the NIV(+) group (2.85, p = 0.005, vs. 1.71, p = 0.042).

INTERPRETATION

In patients with ALS, EMBE > 2 mmol/l predicts nocturnal hypercapnia and shorter survival. Negative effects of sleep-disordered breathing on survival are statistically abolished by sustained NIV.

Patterns of grey and white matter changes differ between bulbar and limb onset amyotrophic lateral sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease that is characterized by a high heterogeneity in patients' disease course. Patients with bulbar onset of symptoms (b-ALS) have a poorer prognosis than patients with limb onset (l-ALS). However, neuroimaging correlates of the assumed biological difference between b-ALS and l-ALS may have been obfuscated by patients' diversity in the disease course. We conducted Voxel-Based-Morphometry (VBM) and Tract-Based-Spatial-Statistics (TBSS) in a group of 76 ALS patients without clinically relevant cognitive deficits. The subgroups of 26 b-ALS and 52 l-ALS patients did not differ in terms of disease Phase or disease aggressiveness according to the D50 progression model. VBM analyses showed widespread ALS-related changes in grey and white matter, that were more pronounced for b-ALS. TBSS analyses revealed that b-ALS was predominantly characterized by frontal fractional anisotropy decreases. This demonstrates a higher degree of neurodegenerative burden for the group of b-ALS patients in comparison to l-ALS. Correspondingly, higher bulbar symptom burden was associated with right-temporal and inferior-frontal grey matter density decreases as well as fractional anisotropy decreases in inter-hemispheric and long association tracts. Contrasts between patients in Phase I and Phase II further revealed that b-ALS was characterized by an early cortical pathology and showed a spread only outside primary motor regions to frontal and temporal areas. In contrast, l-ALS showed ongoing structural integrity loss within primary motor-regions until Phase II. We therefore provide a strong rationale to treat both onset types of disease separately in ALS studies.

Clinical Determinants of Disease Progression in Amyotrophic Lateral Sclerosis-A Retrospective Cohort Study

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that is ultimately fatal but characterized by substantial phenotypic heterogeneity, which is known to impact long-term course and survival. This study investigated clinical determinants of disease progression and outcome in a large cohort of patients with ALS. Methods: Retrospective analysis included comprehensive data from 625 patients who attended a tertiary ALS centre at least twice. Patients were stratified according to five distinct clinical phenotypes: classical ALS; bulbar ALS; ALS with frontotemporal dementia (ALS-FTD); upper motor neuron predominant (UMNP); and lower motor neuron predominant (LMNP). Results: This study confirmed higher age at symptom onset, shorter latency to diagnosis and more rapid decline in the revised ALS Functional Rating Scale sum score as predictors of poor prognosis. Hazard ratios for shorter survival were higher in patients with ALS-FTD versus classical ALS, and in patients with versus without chronic obstructive pulmonary disease (COPD). Mean survival was longest in the UMNP phenotype group. Conclusions: This study confirmed established predictors of shorter survival in ALS and showed that concomitant COPD in particular relates to poor outcome.

Muscle Function Differences between Patients with Bulbar and Spinal Onset Amyotrophic Lateral Sclerosis. Does It Depend on Peripheral Glucose?

BACKGROUND

One of the pathogenic mechanisms of ALS disease is perturbed energy metabolism particularly glucose metabolism. Given the substantial difference in the severity and the prognosis of the disease, depending on whether it has a bulbar or spinal onset, the aim of the study was to determine metabolic differences between both types of ALS, as well as the possible relationship with muscle function.

MATERIALS AND METHODS

A descriptive, analytical, quantitative, and transversal study was carried out in hospitals and Primary Care centers in the region of Valencia, Spain. Fasting glucose and alkaline phosphatase (AP) levels in venous blood, muscle percentage, fat percentage, muscle strength (MRC scale), and functional capacity (Barthel Index) were measured in 31 patients diagnosed with ALS (20 with spinal onset ALS and 11 with bulbar onset ALS). A healthy control of 29 people was included.

RESULTS

No significant differences were observed in blood AP and glucose levels between spinal onset and bulbar onset ALS patients. However, a significant positive correlation was observed between the mean values of both substances in patients with spinal onset ALS. Moreover, a lower percentage of muscle mass and a higher percentage of fat mass were also seen in spinal ALS patients, who also presented lower muscle strength and lower functional capacity.

CONCLUSION

The results of this study seem to point to a possible difference in the peripheral use of glucose between patients with bulbar onset ALS and spinal onset ALS, who appear to have possible insulin resistance. These metabolic differences could explain the lower muscle percentage and lower muscular function in spinal onset ALS patients, although further studies are required.

The links between diabetes mellitus and amyotrophic lateral sclerosis

ALS etiology and prognostic factors are mostly unknown. Metabolic diseases and especially diabetes mellitus (DM) have been variously related to ALS. However, pieces of evidence have been variegated and often conflicting so far. This review aims to give an overview of recent contributions focusing on the relationship between DM and ALS. DM seems to reduce the risk of developing ALS if diagnosed at a younger age; conversely, when diagnosed at an older age, DM seems protective against ALS. Such a relationship was not confirmed in Asian countries where DM increases the risk of ALS independently of the age of onset. Interestingly, DM does not affect ALS prognosis, possibly weakening the potential causal relationship between the two diseases. However, since most studies are observational, it is difficult to state the exact nature of such a relationship and several hypotheses have been made. A recent study using Mendelian randomization suggested that DM is indeed protective against ALS in the European population. However, these analyses are not without limits and further evidence is needed. DM is usually the core of a larger metabolic syndrome. Thus, other metabolic changes such as dyslipidemia, body mass index, and cardiovascular diseases should be collectively considered. Finally, hypermetabolism usually found in ALS patients should be considered too since all these metabolic changes could be compensation (or the cause) of the higher energy expenditure.

Age at symptom onset influences cortical thinning distribution and survival in amyotrophic lateral sclerosis

PURPOSE

The lifetime risk of developing amyotrophic lateral sclerosis (ALS) increases in the elderly, and greater age at symptom onset has been identified as a negative prognostic factor in the disease. However, the underlying neurobiological mechanisms are still poorly investigated. We hypothesized that older age at symptom onset would have been associated with greater extra-motor cortical damage contributing to worse prognosis, so we explored the relationship between age at symptom onset, cortical thinning (CT) distribution, and clinical markers of disease progression.

METHODS

We included 26 ALS patients and 29 healthy controls with T1-weighted magnetic resonance imaging (MRI). FreeSurfer 6.0 was used to identify regions of cortical atrophy (CA) in ALS, and to relate age at symptom onset to CT distribution. Linear regression analyses were then used to investigate whether MRI metrics of age-related damage were predictive of clinical progression. MRI results were corrected using the Monte Carlo simulation method, and regression analyses were further corrected for disease duration.

RESULTS

ALS patients exhibited significant CA mainly encompassing motor regions, but also involving the cuneus bilaterally and the right superior parietal cortex (p < 0.05). Older age at symptom onset was selectively associated with greater extra-motor (frontotemporal) CT, including pars opercularis bilaterally, left middle temporal, and parahippocampal cortices (p < 0.05), and CT of these regions was predictive of shorter survival (p = 0.004, p = 0.03).

CONCLUSION

More severe frontotemporal CT contributes to shorter survival in older ALS patients. These findings have the potential to unravel the neurobiological mechanisms linking older age at symptom onset to worse prognosis in ALS.

Current application of neurofilaments in amyotrophic lateral sclerosis and future perspectives

Motor neuron disease includes a heterogeneous group of relentless progressive neurological disorders defined and characterized by the degeneration of motor neurons. Amyotrophic lateral sclerosis is the most common and aggressive form of motor neuron disease with no effective treatment so far. Unfortunately, diagnostic and prognostic biomarkers are lacking in clinical practice. Neurofilaments are fundamental structural components of the axons and neurofilament light chain and phosphorylated neurofilament heavy chain can be measured in both cerebrospinal fluid and serum. Neurofilament light chain and phosphorylated neurofilament heavy chain levels are elevated in amyotrophic lateral sclerosis, reflecting the extensive damage of motor neurons and axons. Hence, neurofilaments are now increasingly recognized as the most promising candidate biomarker in amyotrophic lateral sclerosis. The potential usefulness of neurofilaments regards various aspects, including diagnosis, prognosis, patient stratification in clinical trials and evaluation of treatment response. In this review paper, we review the body of literature about neurofilaments measurement in amyotrophic lateral sclerosis. We also discuss the open issues concerning the use of neurofilaments clinical practice, as no overall guideline exists to date; finally, we address the most recent evidence and future perspectives.

Beyond the Traditional Clinical Trials for Amyotrophic Lateral Sclerosis and The Future Impact of Gene Therapy

Amyotrophic lateral sclerosis (ALS) is a devastating and incurable motor neuron (MN) disorder affecting both upper and lower MNs. Despite impressive advances in the understanding of the disease’s pathological mechanism, classical pharmacological clinical trials failed to provide an efficient cure for ALS over the past twenty years. Two different gene therapy approaches were recently approved for the monogenic disease Spinal muscular atrophy, characterized by degeneration of lower MNs. This milestone suggests that gene therapy-based therapeutic solutions could be effective for the treatment of ALS. This review summarizes the possible reasons for the failure of traditional clinical trials for ALS. It provides then a focus on the advent of gene therapy approaches for hereditary forms of ALS. Specifically, it describes clinical use of antisense oligonucleotides in three familial forms of ALS, caused by mutations in SOD1, C9orf72 and FUS genes, respectively.. Clinical and pre-clinical studies based on AAV-mediated gene therapy approaches for both familial and sporadic ALS cases are presented as well. Overall, this overview highlights the potential of gene therapy as a transforming technology that will have a huge impact on treatment perspective for ALS patients and on the design of future clinical trials.

l-Serine Reduces Spinal Cord Pathology in a Vervet Model of Preclinical ALS/MND

The early neuropathological features of amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) are protein aggregates in motor neurons and microglial activation. Similar pathology characterizes Guamanian ALS/Parkinsonism dementia complex, which may be triggered by the cyanotoxin β-N-methylamino-l-alanine (BMAA). We report here the occurrence of ALS/MND-type pathological changes in vervets (Chlorocebus sabaeus; n = 8) fed oral doses of a dry powder of BMAA HCl salt (210 mg/kg/day) for 140 days. Spinal cords and brains from toxin-exposed vervets were compared to controls fed rice flour (210 mg/kg/day) and to vervets coadministered equal amounts of BMAA and l-serine (210 mg/kg/day). Immunohistochemistry and quantitative image analysis were used to examine markers of ALS/MND and glial activation. UHPLC-MS/MS was used to confirm BMAA exposures in dosed vervets. Motor neuron degeneration was demonstrated in BMAA-dosed vervets by TDP-43⁺ proteinopathy in anterior horn cells, by reactive astrogliosis, by activated microglia, and by damage to myelinated axons in the lateral corticospinal tracts. Vervets dosed with BMAA + l-serine displayed reduced neuropathological changes. This study demonstrates that chronic dietary exposure to BMAA causes ALS/MND-type pathological changes in the vervet and coadministration of l-serine reduces the amount of reactive gliosis and the number of protein inclusions in motor neurons.

Multiple-Tissue Integrative Transcriptome-Wide Association Studies Discovered New Genes Associated With Amyotrophic Lateral Sclerosis

Genome-wide association studies (GWAS) have identified multiple causal genes associated with amyotrophic lateral sclerosis (ALS); however, the genetic architecture of ALS remains completely unknown and a large number of causal genes have yet been discovered. To full such gap in part, we implemented an integrative analysis of transcriptome-wide association study (TWAS) for ALS to prioritize causal genes with summary statistics from 80,610 European individuals and employed 13 GTEx brain tissues as reference transcriptome panels. The summary-level TWAS analysis with single brain tissue was first undertaken and then a flexible p-value combination strategy, called summary data-based Cauchy Aggregation TWAS (SCAT), was proposed to pool association signals from single-tissue TWAS analysis while protecting against highly positive correlation among tests. Extensive simulations demonstrated SCAT can produce well-calibrated p-value for the control of type I error and was often much more powerful to identify association signals across various scenarios compared with single-tissue TWAS analysis. Using SCAT, we replicated three ALS-associated genes (i.e., ATXN3, SCFD1, and C9orf72) identified in previous GWASs and discovered additional five genes (i.e., SLC9A8, FAM66D, TRIP11, JUP, and RP11-529H20.6) which were not reported before. Furthermore, we discovered the five associations were largely driven by genes themselves and thus might be new genes which were likely related to the risk of ALS. However, further investigations are warranted to verify these results and untangle the pathophysiological function of the genes in developing ALS.

Disease aggressiveness signatures of amyotrophic lateral sclerosis in white matter tracts revealed by the D50 disease progression model

Numerous neuroimaging studies in amyotrophic lateral sclerosis (ALS) have reported links between structural changes and clinical data; however phenotypic and disease course heterogeneity have occluded robust associations. The present study used the novel D50 model, which distinguishes between disease accumulation and aggressiveness, to probe correlations with measures of diffusion tensor imaging (DTI). DTI scans of 145 ALS patients and 69 controls were analyzed using tract‐based‐spatial‐statistics of fractional anisotropy (FA), mean‐ (MD), radial (RD), and axial diffusivity (AD) maps. Intergroup contrasts were calculated between patients and controls, and between ALS subgroups: based on (a) the individual disease covered (Phase I vs. II) or b) patients' disease aggressiveness (D50 value). Regression analyses were used to probe correlations with model‐derived parameters. Case–control comparisons revealed widespread ALS‐related white matter pathology with decreased FA and increased MD/RD. These affected pathways showed also correlations with the accumulated disease for increased MD/RD, driven by the subgroup of Phase I patients. No significant differences were noted between patients in Phase I and II for any of the contrasts. Patients with high disease aggressiveness (D50 < 30 months) displayed increased AD/MD in bifrontal and biparietal pathways, which was corroborated by significant voxel‐wise regressions with D50. Application of the D50 model revealed associations between DTI measures and ALS pathology in Phase I, representing individual disease accumulation early in disease. Patients' overall disease aggressiveness correlated robustly with the extent of DTI changes. We recommend the D50 model for studies developing/validating neuroimaging or other biomarkers for ALS.

Diet, Microbiota and Brain Health: Unraveling the Network Intersecting Metabolism and Neurodegeneration

Increasing evidence gives support for the idea that extra-neuronal factors may affect brain physiology and its predisposition to neurodegenerative diseases. Epidemiological and experimental studies show that nutrition and metabolic disorders such as obesity and type 2 diabetes increase the risk of Alzheimer's and Parkinson's diseases after midlife, while the relationship with amyotrophic lateral sclerosis is uncertain, but suggests a protective effect of features of metabolic syndrome. The microbiota has recently emerged as a novel factor engaging strong interactions with neurons and glia, deeply affecting their function and behavior in these diseases. In particular, recent evidence suggested that gut microbes are involved in the seeding of prion-like proteins and their spreading to the central nervous system. Here, we present a comprehensive review of the impact of metabolism, diet and microbiota in neurodegeneration, by affecting simultaneously several aspects of health regarding energy metabolism, immune system and neuronal function. Advancing technologies may allow researchers in the future to improve investigations in these fields, allowing the buildup of population-based preventive interventions and development of targeted therapeutics to halt progressive neurologic disability.

The 6-min walk test as a new outcome measure in Amyotrophic lateral sclerosis

One of the issues highlighted in amyotrophic lateral sclerosis (ALS) clinical trials is the lack of appropriate outcome measures. The aim of this multicentric study was to evaluate the 6-min walk test (6MWT) as tool to monitor the natural history of a cohort of ALS patients followed up over a 6-month interval. Forty-four ambulant patients were assessed at baseline and after 1, 3 and 6 months. Eight out of forty-four lost the ability to walk before the end of the study. The 6MWT and the objective measures linked to motor function, such as 10 m walking test (10MWT) and Time-up and go (TUG), the ALSFRS-R and the ALSFRS-R items 7–9 showed a good responsiveness to change over the 6-month interval. There was a strong correlation between 6 and 10MWT, TUG, ALSFRS-R, ALSFRS-R items 7–9 and FVC% at baseline. There was no correlation with Edinburgh Cognitive and Behavioural ALS Screen (ECAS) and Modified Borg Scale (MBS). The Δ of 6MWT from T0 to T6 significantly correlated with the Δs of 10MWT and TUG. There was no correlation with the Δs of ALSFRS-R, ALSFRS-R items 7 9, ECAS, MBS and FVC%. The discordance between changes of the 6MWT and ALSFRS-R at 6 month highlights the different content validity among these instruments. The concordance among 6MWT, 10MWT and TUG indicates that the 6MWT is an objective, sensitive and robust tool to measure motor performances in a longitudinal setting. The main limitations of our study were the small sample size and the high percentage of patients (18%) lost at follow-up. Therefore, further studies on larger cohorts, and exploring the relation between 6MWT and need of ventilator support or survival could strengthen our results.

Honeybee products and edible insect powders improve locomotive and learning abilities of Ubiquilin-knockdown Drosophila

BACKGROUND

Mutations in the human Ubiquilin 2 gene are associated with neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) with or without frontotemporal dementia (FTD), the fatal neurodegenerative disease that progressively affected neuronal cells in both brain and spinal cord. There is currently no effective therapy for these diseases. Over the last decade, researchers have focused on the potential use of natural products especially in neurodegenerative studies. Insect products have been used as traditional medicines, however, scientific information is still lacking. Fruit fly is recently used as a model organism to investigate degenerative diseases related to the nervous system because it has a short life span and produces a large number of offspring.

METHODS

The present study investigated the effects of honeybee products and edible insect powders on the locomotive and learning abilities, neuromuscular junctions (NMJs) structure, and reactive oxygen species (ROS) in larval brains of Ubiquilin- knockdown Drosophila.

RESULTS

dUbqn knockdown flies showed defects in locomotive and learning abilities accompanied with structural defects in NMJs. The results obtained revealed that the recovery of locomotive defects was significantly greater in dUbqn knockdown flies fed with coffee honey from Apis cerana (1% v/v) or Apis dorsata melittin (0.5 μg/ml) or wasp powder (2 mg/ml) than that of in untreated dUbqn knockdown flies. Furthermore, dUbqn knockdown flies fed with coffee honey showed the partial rescue of structural defects in NMJs, improved learning ability, and reduced the accumulation of ROS caused by dUbqn depletion in the brain over the untreated group.

CONCLUSION

These results suggest that coffee honey from Apis cerana contains a neuroprotective agent that will contribute to the development of a novel treatment for ALS/FTD.

Accelerated transsulfuration metabolically defines a discrete subclass of amyotrophic lateral sclerosis patients

Amyotrophic lateral sclerosis is a disease characterized by progressive paralysis and death. Most ALS-cases are sporadic (sALS) and patient heterogeneity poses challenges for effective therapies. Applying metabolite profiling on 77-sALS patient-derived-fibroblasts and 43-controls, we found ~25% of sALS cases (termed sALS-1) are characterized by transsulfuration pathway upregulation, where methionine-derived-homocysteine is channeled into cysteine for glutathione synthesis. sALS-1 fibroblasts selectively exhibited a growth defect under oxidative conditions, fully-rescued by N-acetylcysteine (NAC). [U–¹³C]-glucose tracing showed transsulfuration pathway activation with accelerated glucose flux into the Krebs cycle. We established a four-metabolite support vector machine model predicting sALS-1 metabotype with 97.5% accuracy. Both sALS-1 metabotype and growth phenotype were validated in an independent cohort of sALS cases. Importantly, plasma metabolite profiling identified a system-wide cysteine metabolism perturbation as a hallmark of sALS-1. Findings reveal that sALS patients can be stratified into distinct metabotypes with differential sensitivity to metabolic stress, providing novel insights for personalized therapy.

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

OBJECTIVE

To compare the effect of riluzole on median survival in population studies of patients with amyotrophic lateral sclerosis (ALS) with that observed in clinical trials. Methods: Two independent PubMed searches were conducted, to identify population studies that reported median survival for ALS patients who were either treated with riluzole or remained riluzole-free. Results: We identified 14 studies that met the inclusion criteria of reporting median survival and an additional study that reported mean survival of both riluzole and riluzole-free patients. Analysis of the 15 studies found that a majority reported increased survival of riluzole vs. riluzole-free patients. In 8 studies, the median survival for patients treated with riluzole was 6-19 months longer compared with patients not treated with riluzole (p < 0.05). Three additional studies reported a clinically meaningful treatment effect (range 3-5.9 months) but did not meet statistical significance. The remaining 4 studies did not show a meaningful treatment effect between riluzole and riluzole-free groups (<3 months), and differences among the groups were not significant. Also, 5 of the studies used multivariate regression analysis to investigate the level of association between treatment with riluzole and survival; these analyses supported the positive effect of riluzole on survival. Conclusions: A majority of population studies that compared riluzole vs. riluzole-free ALS patients found significant differences in median survival between the two groups, ranging from 6 to 19 months. This is substantially longer than the 2- to 3-month survival benefit observed in the pivotal clinical trials of riluzole.

Structural MRI outcomes and predictors of disease progression in amyotrophic lateral sclerosis

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Serial diffusion tensor (DT) MRI showed progression of white matter pathology in ALS.

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Early involvement of motor fibers and later spread to extra-motor regions was found.

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DT MRI measures of damage to the motor networks showed consistent worsening.

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These correlated with clinical progression and long-term functional prognosis.

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No significant cortical thinning was detected either at baseline or over time.

Background and aims

Considering the great heterogeneity of amyotrophic lateral sclerosis (ALS), the identification of accurate prognostic predictors is fundamental for both the clinical practice and the design of treatment trials. This study aimed to explore the progression of clinical and structural brain changes in patients with ALS, and to assess magnetic resonance imaging (MRI) measures of brain damage as predictors of subsequent functional decline.

Methods

50 ALS patients underwent clinical evaluations and 3 T MRI scans at regular intervals for a maximum of 2 years (total MRI scans = 164). MRI measures of cortical thickness, as well as diffusion tensor (DT) metrics of microstructural damage along white matter (WM) tracts were obtained. Voxel-wise regression models and longitudinal mixed-effects models were used to test the relationship between clinical decline and baseline and longitudinal MRI features.

Results

The rate of decline of the ALS Functional Rating Scale revised (ALSFRS-r) was significantly associated with the rate of fractional anisotropy (FA) decrease in the body of the corpus callosum (CC). Corticospinal tract (CST) and CC-body alterations had a faster progression in patients with higher baseline ALSFRS-r scores and greater CC-body disruption at baseline. Lower FA of the cerebral peduncle was associated with faster subsequent clinical progression.

Conclusions

In this longitudinal study, we identified a significant association between measures of WM damage of the motor tracts and functional decline in ALS patients. Our data suggest that a multiparametric approach including DT MRI measures of brain damage would provide an optimal method for an accurate stratification of ALS patients into prognostic classes.

Sleep and Sleep Disruption in Amyotrophic Lateral Sclerosis

PURPOSE OF REVIEW

In amyotrophic lateral sclerosis (ALS), sleep disruption is frequently present and substantially adds to disease burden. This review aims to summarize current knowledge on causes, pathophysiology, and treatment of sleep disturbances in ALS.

RECENT FINDINGS

Motor neuron degeneration and muscle weakness may lead to muscle cramps, pain, spasticity, immobilization, restless legs, sleep-disordered breathing, and difficulties to clear secretions. Furthermore, existential fears and depression may promote insomnia. Sleep-disordered breathing, and nocturnal hypoventilation in particular, requires ventilatory support which meaningfully prolongs survival and improves health-related quality of life albeit respiratory failure is inevitable. Early indication for non-invasive ventilation can be achieved by inclusion of capnometry in diagnostic sleep studies. Sleep disruption is extremely common in ALS and may arise from different etiologies. The absence of causative therapeutic options for ALS underlines the importance of symptomatic and palliative treatment strategies that acknowledge sleep-related complaints.

Minimizing the Diagnostic Delay in Amyotrophic Lateral Sclerosis: The Role of Nonneurologist Practitioners

Introduction

Amyotrophic lateral sclerosis (ALS), usually fatal in a few years, is a neurodegenerative disorder where the diagnostic delay, although variable according to the studies, remains too long. The main objective of this study was to determine the average time to diagnose ALS and the role of each physician, general practitioner (GP), or specialist (neurologist or not) involved in the management of these patients. The secondary objective was to propose some simple schemes to quickly identify an ALS suspicion with the aim to reduce this delay. Patients and Methods. This retrospective study evaluated the diagnostic delay (and other intermediate delays) of 90 ALS patients registered in the ALS Center of Bordeaux (France) in 2013. The main clinical signs encountered (and their order of appearance) were studied.

Results

The average diagnostic delay was 17 months, with a median diagnostic delay of 12 months. The average diagnostic delay was 2.7 months between the first symptoms and the first complaint to GP, followed by an additional 6.5 month delay before the patient's first visit to a neurologist. This period could be shortened, especially if GP performed additional tests quickly (p=0.01), as the time spent consulting various specialists often extends this crucial step. Overall, diagnostic delay accounted for 40% of the total duration of the disease progression.

Conclusion

In relation to total survival time, the diagnostic delay of ALS appears to be proportionately very long, sometimes longer than that observed in previous studies (because it also included the total delay to diagnostic or treatment initiation). The rapid execution of useful additional tests by the first medical doctor, often GP (with the help of a neurologist), considerably reduces the diagnostic delay. The central role of GP seems to be crucial in the management of patients with ALS. The main objective is, of course, to initiate appropriate treatment and care as soon as possible. Finally, based on our results, we also provide a short practical diagram to help nonneurologist practitioners to quickly discuss the diagnosis of ALS in case of some specific symptoms (“red flags”).

Burden of Rare Variants in ALS and Axonal Hereditary Neuropathy Genes Influence Survival in ALS: Insights from a Next Generation Sequencing Study of an Italian ALS Cohort

Although the genetic architecture of amyotrophic lateral sclerosis (ALS) is incompletely understood, recent findings suggest a complex model of inheritance in ALS, which is consistent with a multistep pathogenetic process. Therefore, the aim of our work is to further explore the architecture of ALS using targeted next generation sequencing (NGS) analysis, enriched in motor neuron diseases (MND)-associated genes which are also implicated in axonal hereditary motor neuropathy (HMN), in order to investigate if disease expression, including the progression rate, could be influenced by the combination of multiple rare gene variants. We analyzed 29 genes in an Italian cohort of 83 patients with both familial and sporadic ALS. Overall, we detected 43 rare variants in 17 different genes and found that 43.4% of the ALS patients harbored a variant in at least one of the investigated genes. Of note, 27.9% of the variants were identified in other MND- and HMN-associated genes. Moreover, multiple gene variants were identified in 17% of the patients. The burden of rare variants is associated with reduced survival and with the time to reach King stage 4, i.e., the time to reach the need for percutaneous endoscopic gastrostomy (PEG) positioning or non-invasive mechanical ventilation (NIMV) initiation, independently of known negative prognostic factors. Our data contribute to a better understanding of the molecular basis of ALS supporting the hypothesis that rare variant burden could play a role in the multistep model of disease and could exert a negative prognostic effect. Moreover, we further extend the genetic landscape of ALS to other MND-associated genes traditionally implicated in degenerative diseases of peripheral axons, such as HMN and CMT2.

Serum phosphorylated neurofilament heavy-chain levels reflect phenotypic heterogeneity and are an independent predictor of survival in motor neuron disease

To investigate the prognostic role and the major determinants of serum phosphorylated neurofilament heavy -chain (pNfH) concentration across a large cohort of motor neuron disease (MND) phenotypes. Enzyme-linked immunosorbent assay (ELISA) was used to measure serum pNfH concentration in 219 MND patients consecutively enrolled in our tertiary MND clinic. A multifactorial analysis was carried out to investigate the major clinical determinants of serum pNfH. Kaplan–Meier survival curves and Cox regression analysis were performed to explore the prognostic value of serum pNfH. Serum pNfH levels were not homogenous among MND phenotypes; higher concentrations in pyramidal, bulbar, and classic phenotypes were observed. C9orf72-MND exhibited higher pNfH concentrations compared to non-C9orf72 MND. Multiple linear regression analysis revealed mean MEP/cMAP and disease progression rate as the two major predictors of serum pNfH levels (R² = 0.188; p ≤ 0.001). Kaplan–Meier curves showed a significant difference of survival among MND subgroups when divided into quartiles based on pNfH concentrations, log-rank X² = 53.0, p ≤ 0.0001. Our study evidenced that higher serum pNfH concentration is a negative independent prognostic factor for survival. In Cox multivariate model, pNfH concentration showed the highest hazard ratio compared to the other factors influencing survival included in the analysis. pNfH differs among the MND phenotypes and is an independent prognostic factor for survival. This study provides supporting evidence of the role of pNfH as useful prognostic biomarker for MND patients. Neurofilament measurements should be considered in the future prognostic models and in clinical trials for biomarker-based stratification, and to evaluate treatment response.

Improvements in the multidisciplinary care are beneficial for survival in amyotrophic lateral sclerosis (ALS): experience from a tertiary ALS center

Objective: The Ljubljana ALS Centre, established in 2002, is the only tertiary center for amyotrophic lateral sclerosis (ALS) in Slovenia. The aim of our study was to evaluate the impact of therapeutic interventions and improvements in the multidisciplinary care on the survival of our patients.Methods: All patients diagnosed with ALS at our center during years 2003-2005 (early group) and 2011-2012 (late group) were included in this retrospective cohort study (n = 124). Kaplan-Meier survival analysis and multiple regression analysis with Cox proportional hazards model were performed to compare survival and to evaluate the differences between the two cohorts.Results: Median survival from the time of diagnosis was 13.0 (95% CI 10.2-15.8) months in the early group and 21.8 (95% CI 17.2-26.4) months in the late group (p = 0.005). In the Cox proportional hazards analysis, the late group of patients was associated with better survival independently of all other prognostic factors (hazard ratio (HR)=0.51, 95% CI = 0.32-0.81, p = 0.004). Survival was also associated with patients' age, use of noninvasive ventilation (NIV) and gastrostomy. The model fit significantly improved when the interaction between the NIV use and the observed time period was added to the model (HR = 0.34, 95% CI = 0.12-0.96, p = 0.041).Conclusions: Our findings suggest that improvements in the multidisciplinary care were beneficial for survival of our patients with ALS. The survival benefit in the late group of our patients could be partially explained by the improvements in the NIV use at our center.