Impact of comorbidities and co-medication on disease onset and progression in a large German ALS patient group

Increased risk of ischemic stroke in amyotrophic lateral sclerosis: a nationwide cohort study in South Korea

BACKGROUND

We investigated the risk of ischemic stroke in ALS and analyzed the effect of ALS-related physical disability using the Korean National Health Insurance Service database.

METHODS

A total of 2,251 ALS patients diagnosed between January 1, 2012, and December 31, 2015, and 1:10 age- and sex-matched control populations were included. Cases that participated in the national health check-up programs were selected. A Cox hazard regression model was used to examine the hazard ratios (HRs) for ischemic stroke in ALS after adjusting for potential confounders.

RESULTS

A total of 681 ALS patients and 10,934 non-ALS participants were selected. ALS patients were slightly younger than the control group (60.3 ± 10.1 years vs. 61.0 ± 10.5 years, p = 0.105), and the proportion of male patients was similar between the two groups (61.6% vs. 60.9%, p = 0.722). ALS patients were more likely to have a lower body mass index (23.1 ± 2.92 vs. 24.0 ± 3.1, p < 0.001) and obstructive sleep apnea syndrome (0.59% vs. 0.06%, p < 0.001) than the controls. In ALS patients, the incidence rate of ischemic stroke was 6.32 per 1,000 person-years, and the adjusted HR of ischemic stroke was 2.58 (95% confidence interval 1.38 - 4.82) compared with the matched group. The risk of ischemic stroke did not differ by the presence of disability in ALS patients.

CONCLUSIONS

Our findings suggest that ALS patients have an increased risk of ischemic stroke compared with controls, but the risk did not differ by the presence of disability in ALS.

Rare Diseases, Spotlighting Amyotrophic Lateral Sclerosis, Huntington's Disease, and Myasthenia Gravis: Insights from Landscape Analysis of Current Research

Rare diseases are a diverse group of disorders that, despite each individual condition's rarity, collectively affect a significant portion of the global population. Currently approximately 10,000 rare diseases exist globally, with 80% of these diseases being identified as having genetic origins. In this Review, we examine data from the CAS Content Collection to summarize scientific progress in the area of rare diseases. We examine the publication landscape in the area in an effort to provide insights into current advances and developments. We then discuss the evolution of key concepts in the field, genetic associations, as well as the major technologies and development pipelines of rare disease treatments. We focus our attention on three specific rare diseases: (i) amyotrophic lateral sclerosis, a terminal neurodegenerative disease affecting the central nervous system resulting in progressive loss of motor neurons that control voluntary muscles; (ii) Huntington's disease, another terminal neurodegenerative disease that causes progressive degeneration of nerve cells in the brain, with a wide impact on a person's functional abilities; and (iii) myasthenia gravis, a chronic autoimmune synaptopathy leading to skeletal muscle weakness. While the pathogenesis of these rare diseases is being elucidated, there is neither a cure nor preventative treatment available, only symptomatic treatment. The objective of the paper is to provide a broad overview of the evolving landscape of current knowledge on rare diseases and specifically on the biology and genetics of the three spotlighted diseases, to outline challenges and evaluate growth opportunities, an aim to further efforts in solving the remaining challenges.

Association between cardiometabolic diseases and the risk and progression of motor neuron diseases in Sweden: a population-based case-control study

Background

The evidence on the link between cardiometabolic diseases (CMDs) and motor neuron diseases (MNDs) remains inconsistent. We aimed to determine whether there is an association of CMDs, namely, any cardiovascular disease, cardiac arrhythmia, heart failure, thromboembolic disease, hypertension, cerebrovascular disease, ischemic heart disease, diabetes mellitus type 2, and hypercholesterolemia with the risk and progression of MNDs.

Methods

We included 1463 MND patients (amyotrophic lateral sclerosis (ALS), primary lateral sclerosis (PLS), progressive spinal muscular atrophy (PSMA), and unspecified MND) diagnosed from January 1, 2015, to July 1, 2023, in Sweden according to the Swedish Motor Neuron Disease Quality Registry (i.e., cases), up to 5 MND-free population controls per case (N = 7311) who were individually matched to the cases on age and sex, and the full siblings (N = 2002) and spouses (N = 1220) of MND patients (i.e., relative controls). Conditional logistic regression models were used to estimate the risk of MND diagnosis in relation to previous CMDs, through comparing MND patients to population controls or relative controls. MND patients were followed from diagnosis to assess the role of pre-diagnostic CMDs on disease progression. A joint longitudinal-survival model was used to estimate risk of mortality (or use of invasive ventilation) in relation to CMDs after taking into account the longitudinal changes of ALS functional rating scale-revised (ALSFRS-R) in the time-to-event analysis. Hierarchical clustering with the Ward's linkage and a dissimilarity matrix created by Gower's method was used to identify clusters of MND patients with distinct phenotypes.

Findings

Among the CMDs studied, a history of diabetes mellitus type 2 (OR 0.75; 95% CI 0.62, 0.93) or hypercholesterolemia (OR 0.82; 95% CI 0.71, 0.94) more than one year before diagnosis was associated with a lower risk for MNDs. The associations persisted for more than five years before MND diagnosis. MND patients with a history of any cardiovascular disease (HR 1.43; 95% CI 1.13, 1.81), arrhythmia (HR 1.42; 95% CI 1.04, 1.93), heart failure (HR 1.79; 95% CI 1.02, 3.14), hypertension (HR 1.41; 95% CI 1.12, 1.77), or hypercholesterolemia (HR 1.28; 95% CI 1.01, 1.62) had an increased mortality risk, compared to others, after taking into consideration the longitudinal changes in ALSFRS-R. Cluster analysis identified two clusters of MND patients, where one cluster demonstrated higher age, worse functional status, and higher prevalence of CMDs at the time of diagnosis as well as a higher mortality and faster functional decline during follow-up, compared to the ones included in the other cluster.

Interpretation

Diabetes mellitus type 2 and hypercholesterolemia were associated with a lower future risk of MND. On the other hand, most of the CMDs were indicative of a poor disease progression after an MND diagnosis.

Funding

European Research Council, US Center for Disease Control and Prevention, Swedish Research Council.

Genetic Variation in Targets of Antidiabetic Drugs and Amyotrophic Lateral Sclerosis Risk

BACKGROUND

Previous studies have suggested that antidiabetic drug use may be associated with amyotrophic lateral sclerosis. However, these studies are limited by many confounding and reverse causality biases. We aimed to determine whether antidiabetic drug use has causal effects on ALS.

METHODS

Drug-target Mendelian randomization analysis was conducted to evaluate the association between genetic variation in the targets of antidiabetic drugs and ALS risk. The antidiabetic drugs included sulfonylureas, GLP-1 analogues, thiazolidinediones, insulin/insulin analogues, metformin, and SGLT2 inhibitors. Summary statistics for ALS were retrieved from previous genome-wide association studies comprising 27,205 ALS patients and 55,058 controls. The instrumental variables for these drugs are from previous published articles.

RESULTS

Genetic variation in SGLT2 inhibition targets was associated with lower risk of ALS (odds ratio [OR] = 0.32, 95% CI = 0.14-0.74; p = 0.008). We did not find that genetic variation in metformin targets was associated with ALS (OR = 1.61, 95% CI = 0.94-2.73; p = 0.081). Nevertheless, mitochondrial complex I, a target of metformin, was associated with a higher risk of ALS (OR = 1.83, 95% CI = 1.01-3.32; p = 0.047). The analysis showed that genetic variation in sulfonylureas, GLP-1 analogues, thiazolidinediones, insulin or insulin analogues targets was not associated with ALS (all p > 0.05).

CONCLUSIONS

The complex interaction between hypoglycemic, antioxidation, and anti-inflammatory effects may account for the different results across antidiabetic drug types. These findings provide key evidence to guide the use of antidiabetic drugs and will help to identify novel therapeutic targets in ALS.

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.

Non-motor symptoms in patients with amyotrophic lateral sclerosis: current state and future directions

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive degeneration of both upper and lower motor neurons. A defining histopathological feature in approximately 97% of all ALS cases is the accumulation of phosphorylated trans-activation response (TAR) DNA-binding protein 43 protein (pTDP-43) aggregates in the cytoplasm of neurons and glial cells within the central nervous system. Traditionally, it was believed that the accumulation of TDP-43 aggregates and subsequent neurodegeneration primarily occurs in motor neurons. However, contemporary evidence suggests that as the disease progresses, other systems and brain regions are also affected. Despite this, there has been a limited number of clinical studies assessing the non-motor symptoms in ALS patients. These studies often employ various outcome measures, resulting in a wide range of reported frequencies of non-motor symptoms in ALS patients. The importance of assessing the non-motor symptoms reflects in a fact that they have a significant impact on patients' quality of life, yet they frequently go underdiagnosed and unreported during clinical evaluations. This review aims to provide an up-to-date overview of the current knowledge concerning non-motor symptoms in ALS. Furthermore, we address their diagnosis and treatment in everyday clinical practice.

Increased risk of myocardial infarction in amyotrophic lateral sclerosis: A nationwide cohort study in South Korea

BACKGROUND

The risk of myocardial infarction (MI), the major form of CVD, in amyotrophic lateral sclerosis (ALS) is currently unknown. We investigated the risk of MI in ALS and analyzed the effect of ALS-related physical disability on the risk of MI using the Korean National Health Insurance Service database.

METHODS

A total of 659 ALS patients and 10,927 non-ALS participants were finally selected between January 1, 2011, and December 31, 2015. A Cox hazard regression model was used to examine the hazard ratios (HRs) for MI in ALS after adjustment for potential confounders.

RESULTS

The incidence rate of MI was 26.2 per 1000 person-years, and the adjusted HR (aHR) for MI in ALS patients was 10.6 (95% confidence interval [CI] 7.2-15.4) compared with the controls. ALS patients who developed physical disability had an even higher risk of MI (aHR 18.6, 95% CI 11.5-30.0) compared with those who did not develop disability (aHR 7.4, 95% CI 4.6-11.9). The increased risk of MI was more prominent in female subjects than in male subjects (aHR 17.8, 95% CI 10.8-29.4 vs. aHR 6.9, 95% CI 4.1-11.6, P for interaction 0.006) and in obese subjects than in non-obese subjects (aHR 17.8, 95% CI 10.5-30.1 vs. aHR 7.9, 95% CI 4.9-12.8, P for interaction 0.018).

CONCLUSIONS

Our findings suggest that the risk of MI is high in ALS patients compared with a control population, and the risk is more prominent in those who develop physical disability, or who are female or obese.

Cystatin C based estimation of chronic kidney disease and amyotrophic lateral sclerosis in the ALS registry Swabia: associated risk and prognostic value

Kidney function as part of metabolic changes could be associated with amyotrophic lateral-sclerosis (ALS). We investigated the associations between estimated chronic kidney disease (CKD), based on the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) cystatin C equation, and the risk at onset and prognostic value of CKD for ALS. Between October 2010 and June 2014, 362 ALS cases (59.4% men, mean age 65.7 years) and 681 controls (59.5% men, means age 66.3 years) were included in a population-based case-control study based on the ALS registry Swabia in Southern Germany. All ALS cases were followed-up (median 89.7 months), 317 died. Serum samples were measured for cystatin C to estimate the glomerular filtration rate (eGFR) according to the CKD-EPI equation. Information on covariates were assessed by an interview-based standardized questionnaire. Conditional logistic regression models were applied to calculate odds ratios (OR) for risk of ALS associated with eGFR/CKD stages. Time-to-death associated with renal parameters at baseline was assessed in ALS cases only. ALS cases were characterized by lower body mass index, slightly lower smoking prevalence, more intense occupational work and lower education than controls. Median serum cystatin-C based eGFR concentrations were lower in ALS cases than in controls (54.0 vs. 59.5 mL/min pro 1.73 m2). The prevalence of CKD stage ≥ 3 was slightly higher in ALS cases than in controls (14.1 vs. 11.0%). In the adjusted models, CKD stage 2 (OR 1.82, 95% CI 1.32, 2.52) and stage 3 (OR 2.34, 95% CI 1.38, 3.96) were associated with increased ALS risk. In this cohort of ALS cases, eGFR and CKD stage ≥ 3 (HR 0.94; 95% CI 0.64, 1.38) were not associated with prognosis. In this case-control study, higher CKD stages were associated with increased ALS risk, while in the prospective cohort of ALS cases, no indication of an association of CysC-based CKD on mortality was seen. In addition, our work strengthens the importance to evaluate renal function using a marker independent of muscle mass in ALS patients.

Detection of Amyotrophic Lateral Sclerosis (ALS) Comorbidity Trajectories Based on Principal Tree Model Analytics

The multifaceted nature and swift progression of Amyotrophic Lateral Sclerosis (ALS) pose considerable challenges to our understanding of its evolution and interplay with comorbid conditions. This study seeks to elucidate the temporal dynamics of ALS progression and its interaction with associated diseases. We employed a principal tree-based model to decipher patterns within clinical data derived from a population-based database in Taiwan. The disease progression was portrayed as branched trajectories, each path representing a series of distinct stages. Each stage embodied the cumulative occurrence of co-existing diseases, depicted as nodes on the tree, with edges symbolizing potential transitions between these linked nodes. Our model identified eight distinct ALS patient trajectories, unveiling unique patterns of disease associations at various stages of progression. These patterns may suggest underlying disease mechanisms or risk factors. This research re-conceptualizes ALS progression as a migration through diverse stages, instead of the perspective of a sequence of isolated events. This new approach illuminates patterns of disease association across different progression phases. The insights obtained from this study hold the potential to inform doctors regarding the development of personalized treatment strategies, ultimately enhancing patient prognosis and quality of life.

Nutritional and metabolic factors in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease that is classically thought to impact the motor system. Over the past 20 years, research has started to consider the contribution of non-motor symptoms and features of the disease, and how they might affect ALS prognosis. Of the non-motor features of the disease, nutritional status (for example, malnutrition) and metabolic balance (for example, weight loss and hypermetabolism) have been consistently shown to contribute to more rapid disease progression and/or earlier death. Several complex cellular changes observed in ALS, including mitochondrial dysfunction, are also starting to be shown to contribute to bioenergetic failure. The resulting energy depletion in high energy demanding neurons makes them sensitive to apoptosis. Given that nutritional and metabolic stressors at the whole-body and cellular level can impact the capacity to maintain optimal function, these factors present avenues through which we can identify novel targets for treatment in ALS. Several clinical trials are now underway evaluating the effectiveness of modifying energy balance in ALS, making this article timely in reviewing the evidence base for metabolic and nutritional interventions.

Systematic Screening of Associations between Medication Use and Risk of Neurodegenerative Diseases Using a Mendelian Randomization Approach

BACKGROUND

Systematically assessing the causal associations between medications and neurodegenerative diseases is significant in identifying disease etiology and novel therapies. Here, we investigated the putative causal associations between 23 existing medication categories and major neurodegenerative diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS).

METHODS

A two-sample mendelian randomization (MR) approach was conducted. Estimates were calculated using the inverse-variance weighted (IVW) method as the main model. A sensitivity analysis and a pleiotropy analysis were performed to identify potential violations.

RESULTS

Genetically predisposition to antihypertensives (OR = 0.809, 95% CI = 0.668-0.981, p = 0.031), thyroid preparations (OR = 0.948, 95% CI = 0.909-0.988, p = 0.011), and immunosuppressants (OR = 0.879, 95% CI = 0.789-0.979, p = 0.018) was associated with a decreased risk of AD. Genetic proxies for thyroid preparations (OR = 0.934, 95% CI = 0.884-0.988, p = 0.017), immunosuppressants (OR = 0.825, 95% CI = 0.699-0.973, p = 0.022), and glucocorticoids (OR = 0.862, 95% CI = 0.756-0.983, p = 0.027) were causally associated with a decreased risk of PD. Genetically determined antithrombotic agents (OR = 1.234, 95% CI = 1.042-1.461, p = 0.015), HMG CoA reductase inhibitors (OR = 1.085, 95% CI = 1.025-1.148, p = 0.005), and salicylic acid and derivatives (OR = 1.294, 95% CI = 1.078-1.553, p = 0.006) were associated with an increased risk of ALS.

CONCLUSIONS

We presented a systematic view concerning the causal associations between medications and NDs, which will promote the etiology discovery, drug repositioning and patient management for NDs.

Retinal vessels as a window on amyotrophic lateral sclerosis pathophysiology: A systematic review

Amyotrophic lateral sclerosis (ALS) is a rare fatal motor neuron disease. Although many potential mechanisms have been proposed, the pathophysiology of the disease remains unknown. Currently available treatments can only delay the progression of the disease and prolong life expectancy by a few months. There is still no definitive cure for ALS, and the development of new treatments is limited by a lack of understanding of the underlying biological processes that trigger and promote neurodegeneration. Several scientific results suggest a neurovascular impairment in ALS providing perspectives for the development of new biomarkers and treatments. In this article, we performed a systematic review using PRISMA guidelines including PubMed, EmBase, GoogleScholar, and Web of Science Core Collection to analyze the scientific literature published between 2000 and 2021 discussing the neurocardiovascular involvement and ophthalmologic abnormalities in ALS. In total, 122 articles were included to establish this systematic review. Indeed, microvascular pathology seems to be involved in ALS, affecting all the neurovascular unit components. Retinal changes have also been recently highlighted without significant alteration of the visual pathways. Despite the peripheral location of the retina, it is considered as an extension of the central nervous system (CNS) as it displays similarities to the brain, the inner blood-retinal barrier, and the blood-brain barrier. This suggests that the eye could be considered as a 'window' into the brain in many CNS disorders. Thus, studying ocular manifestations of brain pathologies seems very promising in understanding neurodegenerative disorders, mainly ALS. Optical coherence tomography angiography (OCT-A) could therefore be a powerful approach for exploration of retinal microvascularization allowing to obtain new diagnostic and prognostic biomarkers of ALS.

Insight into Elderly ALS Patients in the Emilia Romagna Region: Epidemiological and Clinical Features of Late-Onset ALS in a Prospective, Population-Based Study

Few studies have focused on elderly (>80 years) amyotrophic lateral sclerosis (ALS) patients, who represent a fragile subgroup generally not included in clinical trials and often neglected because they are more difficult to diagnose and manage. We analyzed the clinical and genetic features of very late-onset ALS patients through a prospective, population-based study in the Emilia Romagna Region of Italy. From 2009 to 2019, 222 (13.76%) out of 1613 patients in incident cases were over 80 years old at diagnosis, with a female predominance (F:M = 1.18). Elderly ALS patients represented 12.02% of patients before 2015 and 15.91% from 2015 onwards (p = 0.024). This group presented with bulbar onset in 38.29% of cases and had worse clinical conditions at diagnosis compared to younger patients, with a lower average BMI (23.12 vs. 24.57 Kg/m2), a higher progression rate (1.43 vs. 0.95 points/month), and a shorter length of survival (a median of 20.77 vs. 36 months). For this subgroup, genetic analyses have seldom been carried out (25% vs. 39.11%) and are generally negative. Finally, elderly patients underwent less frequent nutritional- and respiratory-supporting procedures, and multidisciplinary teams were less involved at follow-up, except for specialist palliative care. The genotypic and phenotypic features of elderly ALS patients could help identify the different environmental and genetic risk factors that determine the age at which disease onset occurs. Since multidisciplinary management can improve a patient's prognosis, it should be more extensively applied to this fragile group of patients.

Brain Vascular Health in ALS Is Mediated through Motor Cortex Microvascular Integrity

Brain vascular health appears to be critical for preventing the development of amyotrophic lateral sclerosis (ALS) and slowing its progression. ALS patients often demonstrate cardiovascular risk factors and commonly suffer from cerebrovascular disease, with evidence of pathological alterations in their small cerebral blood vessels. Impaired vascular brain health has detrimental effects on motor neurons: vascular endothelial growth factor levels are lowered in ALS, which can compromise endothelial cell formation and the integrity of the blood-brain barrier. Increased turnover of neurovascular unit cells precedes their senescence, which, together with pericyte alterations, further fosters the failure of toxic metabolite removal. We here provide a comprehensive overview of the pathogenesis of impaired brain vascular health in ALS and how novel magnetic resonance imaging techniques can aid its detection. In particular, we discuss vascular patterns of blood supply to the motor cortex with the number of branches from the anterior and middle cerebral arteries acting as a novel marker of resistance and resilience against downstream effects of vascular risk and events in ALS. We outline how certain interventions adapted to patient needs and capabilities have the potential to mechanistically target the brain microvasculature towards favorable motor cortex blood supply patterns. Through this strategy, we aim to guide novel approaches to ALS management and a better understanding of ALS pathophysiology.

Physical activity as risk factor in amyotrophic lateral sclerosis: a systematic review and meta-analysis

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder with rapid progression and high mortality. Physical activity (PA) has been identified as a major risk factor for ALS. However, the results across studies are still controversial. We aimed to explore the association between different types of PA and ALS.

METHODS

The PubMed, EMBASE, Cochrane and Web of Science databases were systematically searched for case-control and cohort studies which explored the relationship between PA and ALS from inception to October 2022. The data were analyzed to generate a pooled effect and 95% confidence interval (CI).

RESULTS

A total of 16,686 articles were included in the systematic search. After filtering, 28 studies from online database and 6 studies from references of relevant articles remained in the analysis. Individuals with a history of vigorous physical activity (OR 1.26, 95% CI 1.06-1.49), occupational-related activity (OR 1.14, 95% CI 1.04-1.25), leisure time activity (OR 1.08, 95% CI 1.04-1.12), unclassified PA (OR 1.05 95% CI 1.02-1.09) and professional athletes (SMR 5.23, 95% CI 2.67-10.25; SIR 2.54, 95% CI 1.37-4.69) were in higher risk of developing ALS. In contrast, sport-related activity (OR 0.97, 95% CI 0.76-1.26) was not associated with ALS.

CONCLUSIONS

Vigorous physical activity, occupational-related activity, leisure time activity, unclassified PA and professional athletes were associated with a higher risk of ALS, while sport-related activity showed no association with ALS. Our findings clarified the relation between different types of PA and ALS and provided some practicable advice for the lifestyle of high-risk populations.

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.

Risk factors of amyotrophic lateral sclerosis: a global meta-summary

Background

The etiology of amyotrophic lateral sclerosis (ALS) remains largely unknown. This study aimed to summarize the relationship between ALS and its genetic and non-genetic risk factors.

Method

A search of relevant literature from PubMed, Embase, and Cochrane Database from inception to December 2022 was performed. Random-effects or fixed-effects models were performed by Stata MP 15.0 to pool multivariate or adjusted ratios (OR). PROSPERO registration number: CRD42022301549.

Results

230 eligible studies were included, of which 67 involved 22 non-genetic factors, and 163 involved genetic factors. Four aspects of non-genetic factors, including lifestyle, environmental and occupational exposures, pre-existing diseases/comorbidity and medical exposures, and others, were analyzed. Exposure to heavy metals (OR = 1.79), pesticides (OR = 1.46), solvents (OR = 1.37), previous head trauma (OR = 1.37), military service (OR = 1.29), stroke (OR = 1.26), magnetic field (OR = 1.22) and hypertension (OR = 1.04) are significant risk factors, but use of antidiabetics (OR = 0.52), high BMI (OR = 0.60 for obese and overweight vs. normal and underweight), living in urban (OR = 0.70), diabetes mellitus (OR = 0.83), and kidney disease (OR = 0.84) decrease the risk for ALS. In addition, eight common ALS-related genes were evaluated, the mutation frequencies of these genes were ranked from highest to lowest as SOD1 (2.2%), C9orf72 (2.1%), ATXN2 (1.7%), FUS (1.7%), TARDBP (0.8%), VCP (0.6%), UBQLN2(0.6%) and SQSTM1 (0.6%) in all the ALS patients.

Conclusions

Our findings suggested that effective intervention for risk exposure and timely modification of lifestyle might prevent the occurrence of ALS. Genetic mutations are important risk factors for ALS and it is essential to detect genetic mutations correctly and scientifically.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=301549, identifier: CRD42022301549.

Rethinking purinergic concepts and updating the emerging role of P2X7 and P2X4 in amyotrophic lateral sclerosis

The topic of the present review regards the ubiquitous and phylogenetically most ancient prototype of intercellular signaling, the one mediated by extracellular nucleosides and nucleotides, bearing a strong influence on pathophysiological processes in the nervous system. Not by chance, purine and pyrimidine molecules are the most prevalent and ubiquitous chemical messengers in the animal and plant kingdoms, operating through a large plethora of purinergic metabolizing enzymes, P1 and P2 receptors, nucleoside and nucleotide channels and transporters. Because ectonucleotidases degrade the agonists of P2 receptors while simultaneously generate the agonists for P1 receptors, and because several agonists, or antagonists, simultaneously bind and activate, or inhibit, more than one receptor subtype, it follows that an all-inclusive "purinergic network" perspective should be better considered when looking at purinergic actions. This becomes particularly crucial during pathological conditions as for instance amyotrophic lateral sclerosis, where the contribution of purinergic signaling has been demonstrated to differ according to each target cell phenotype and stage of disease progression. Here we will present some newly updated results about P2X7 and P2X4 as the most thoroughly investigated P2 receptors in amyotrophic lateral sclerosis, being aware that the comprehension of their actions is still in progress, and that the purinergic rationale for studying this disease must be however wide-ranging and all-inclusive. This article is part of the Special Issue on 'Purinergic Signaling: 50 years'.

Medication use and risk of amyotrophic lateral sclerosis-a systematic review

BACKGROUND

Studying whether medications act as potential risk factors for amyotrophic lateral sclerosis (ALS) can contribute to the understanding of disease etiology as well as the identification of novel therapeutic targets. Therefore, we conducted a systematic review to summarize the existing evidence on the association between medication use and the subsequent ALS risk.

METHODS

A systematic review was conducted in Medline, Embase, and Web of Science from the date of database establishment to December 10, 2021. References of identified articles were further searched for additional relevant articles. Studies were included if (1) published in English, (2) explored medication use as exposure and development of ALS as outcome, and (3) the design was a human observational study. Clinical trials, reviews, comments, editorials, and case reports were excluded. Quality assessment was performed using a pre-validated tool for non-randomized studies, the Newcastle-Ottawa Assessment Scale (NOS).

RESULTS

Of the 4760 studies identified, 25 articles, including 13 case-control studies, five nested case-control studies, six cohort studies, and one retrospective chart review, were included in the review. Among these studies, there were 22 distinct study populations that included 171,407 patients with ALS, seven classes of medication examined, and 23 studies with a NOS ≥ 5. There was a general lack of agreement between studies on the associations of cholesterol-lowering drugs, anti-inflammatory drugs, immunosuppressants, antibiotics, oral contraceptives (OCs) or hormone replacement therapy (HRT), antihypertensive drugs, antidiabetics, and drugs for psychiatric and neurological disorders with the subsequent risk of ALS. However, it appeared that statins, aspirin, OCs/HRT, antihypertensives, and antidiabetics were unlikely related to a higher risk of ALS. The positive associations noted for antibiotics, antidepressants, and skeletal muscle relaxants might be attributable to prodromal symptoms of ALS.

CONCLUSIONS

There is currently no strong evidence to link any medication use with ALS risk.

The panoramic view of amyotrophic lateral sclerosis: A fatal intricate neurological disorder

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurological disease affecting both upper and lower motor neurons. In the United States alone, there are 16,000-20,000 established cases of ALS. The early disease diagnosis is challenging due to many overlapping pathophysiologies with other neurological diseases. The etiology of ALS is unknown; however, it is divided into two categories: familial ALS (fALS) which occurs due to gene mutations & contributes to 5-10% of ALS, and sporadic ALS (sALS) which is due to environmental factors & contributes to 90-95% of ALS. There is still no curative treatment for ALS: palliative care and symptomatic treatment are therefore essential components in the management of these patients. In this review, we provide a panoramic view of ALS, which includes epidemiology, risk factors, pathophysiologies, biomarkers, diagnosis, therapeutics (natural, synthetic, gene-based, pharmacological, stem cell, extracellular vesicles, and physical therapy), controversies (in the clinical trials of ALS), the scope of nanomedicine in ALS, and future perspectives.

Cardiovascular comorbidities in amyotrophic lateral sclerosis: A systematic review

OBJECTIVE

To summarize the prevalence of the cardiovascular comorbidities in patients with amyotrophic lateral sclerosis (ALS) and explore the impacts of cardiovascular diseases on ALS.

METHODS

PubMed, EMBASE, OVID and Web of Science were searched systematically until July 2021 for studies on the prevalence of cardiovascular diseases among ALS patients or quantitatively investigating the effects of cardiovascular comorbidities on incidence, progression or survival of ALS. We conducted a fixed-effects or random-effects meta-analysis to calculate the summary rate or ORs (odds ratios) with 95 %CIs (confidence intervals).

RESULTS

The comorbidity of hypertension in France (56.9%) was the highest, followed by Portugal (48%). Only 15% of Chinese ALS patients suffered from hypertension. A quarter of ALS patients in America had coronary heart disease while only 4-5% of patients with ALS in Australia or the Netherlands suffered from coronary heart disease. There was significant relationship between hypertension and survival of ALS (OR: 1.04, 95%CI: 1.01, 1.07). Coronary heart disease was considerably related to ALS onset (OR: 1.19, 95%CI: 1.14, 1.24) and heart failure could noticeably accelerate the progression rate of ALS (OR: 6.33, 95%CI: 1.55, 24.84).

CONCLUSIONS

Cardiovascular comorbidities in ALS patients varied significantly with different regions. Hypertension could reduce the survival of ALS so the intensive treatment of chronic hypertension should be recommended to ALS patients in clinical practice. Coronary heart disease could increase the risk of ALS and heart failure was a negative prognostic factor for ALS, which deserved more attention of clinicians.

Prevalence of multimorbidity and its impact on survival in people with motor neuron disease

BACKGROUND AND PURPOSE

This study was undertaken to determine the prevalence of multimorbidity in people with motor neuron disease (MND) and to identify whether specific patterns of multimorbidity impact survival beyond age alone.

METHODS

We performed a retrospective analysis of the Scottish national MND register from 1 January 2015 to 29 October 2019. People with amyotrophic lateral sclerosis, primary lateral sclerosis, progressive muscular atrophy, or progressive bulbar palsy were included. We fitted latent class regression models incorporating comorbidities (class indicators), age, sex, and bulbar onset (covariates), and survival (distal outcome) with multimorbidity as a hypothesised latent variable. We also investigated the association between the Charlson Comorbidity Index and survival in Cox regression and compared its discrimination and calibration to age alone.

RESULTS

A total of 937 people with MND were identified (median age = 67 years, 60.2% male); 64.8% (n = 515) had two or more comorbidities. We identified a subpopulation with high prevalence of cardiovascular disease, but when accounting for the relationship between age and individual comorbidities, there was no difference in survival. Both Charlson Comorbidity Index (hazard ratio [HR] per unit increase = 1.11, 95% confidence interval [CI] = 1.07-1.15, p < 0.0001) and age (HR per year increase = 1.04, 95% CI = 1.03-1.05, p < 0.0001) were significantly associated with survival, but discrimination was higher for age compared to Charlson Comorbidity Index (C-index = 0.63 vs. 0.59).

CONCLUSIONS

Multimorbidity is common in MND, necessitating holistic interdisciplinary management, but age is the dominant predictor of prognosis in people with MND. Excluding people with MND and multimorbidity from trial participation may do little to homogenise the cohort in terms of survival potential and could harm generalisability.

Cardiovascular comorbidities in amyotrophic lateral sclerosis

BACKGROUND

The role of cardiovascular risk factors in amyotrophic lateral sclerosis (ALS) is controversial. A favourable profile has been found in ALS patients, but previous studies have not specifically considered the profile in different disease phenotypes.

METHODS

Demographic data, smoking habits, lifetime exercise, and medical history including diabetes mellitus, arterial hypertension, hypercholesterolemia, hypertriglyceridemia, stroke, and cardiac events, were analysed in ALS patients and in controls with other neurological disorders, utilising a standardized questionnaire applied by the same neurologist. In ALS patients the results were analysed according to their different phenotypes. Univariate analyses and multinomial logistic models were applied to estimate the odds ratios (ORs) and confidence intervals (CIs) for covariates, to test potential modifiers and their effects.

RESULTS

500 consecutively assessed adult ALS patients (mean age 65.6, 47% women, and 136 bulbar-onset) and 327 age and gender-matched controls were studied. Patients with spinal-onset ALS took more exercise (p = 0.012), reported less hypertension (p = 0.002) and had fewer cardiac events (p = 0.012). Multinomial regression analysis showed that men without hypertension have a higher risk of having spinal-onset ALS (p < 0.001) while female with hypertension have a higher risk of having bulbar-onset ALS (p = 0.033).

CONCLUSIONS

Risk-factors in ALS can be influenced by gender and phenotype. This study suggests that men with spinal ALS are healthier, exercise more and have lower rate of hypertension, but females with bulbar-onset ALS are more prone to hypertension. The complex interplay between exercise, diet and comorbidities with ALS phenotype requires further investigation.

What do we know about the variability in survival of patients with amyotrophic lateral sclerosis?

INTRODUCTION

ALS is a fatal neurodegenerative disease. However, patients show variability in the length of survival after symptom onset. Understanding the mechanisms of long survival could lead to possible avenues for therapy.

AREAS COVERED

This review surveys the reported length of survival in ALS, the clinical features that predict survival in individual patients, and possible factors, particularly genetic factors, that could cause short or long survival. The authors also speculate on possible mechanisms.

EXPERT OPINION

a small number of known factors can explain some variability in ALS survival. However, other disease-modifying factors likely exist. Factors that alter motor neurone vulnerability and immune, metabolic, and muscle function could affect survival by modulating the disease process. Knowing these factors could lead to interventions to change the course of the disease. The authors suggest a broad approach is needed to quantify the proportion of variation survival attributable to genetic and non-genetic factors and to identify and estimate the effect size of specific factors. Studies of this nature could not only identify novel avenues for therapeutic research but also play an important role in clinical trial design and personalized medicine.