Novel approaches to assessing upper motor neuron dysfunction in motor neuron disease/amyotrophic lateral sclerosis: IFCN handbook chapter

Identifying upper motor neuron (UMN) dysfunction is fundamental to the diagnosis and understanding of disease pathogenesis in motor neuron disease (MND). The clinical assessment of UMN dysfunction may be difficult, particularly in the setting of severe muscle weakness. From a physiological perspective, transcranial magnetic stimulation (TMS) techniques provide objective biomarkers of UMN dysfunction in MND and may also be useful to interrogate cortical and network function. Single, paired- and triple pulse TMS techniques have yielded novel diagnostic and prognostic biomarkers in MND, and have provided important pathogenic insights, particularly pertaining to site of disease onset. Cortical hyperexcitability, as heralded by reduced short interval intracortical inhibition (SICI) and increased short interval intracortical facilitation, has been associated with the onset of lower motor neuron degeneration, along with patterns of disease spread, development of specific clinical features such as the split hand phenomenon, and may provide an indication about the rate of disease progression. Additionally, reduction of SICI has emerged as a potential diagnostic aid in MND. The triple stimulation technique (TST) was shown to enhance the diagnostic utility of conventional TMS measures in detecting UMN dysfunction in MND. Separately, sophisticated brain imaging techniques have uncovered novel biomarkers of neurodegeneration that have bene associated with progression. The present review will discuss the utility of TMS and brain neuroimaging derived biomarkers of UMN dysfunction in MND, focusing on recently developed TMS techniques and advanced neuroimaging modalities that interrogate structural and functional integrity of the corticomotoneuronal system, with an emphasis on pathogenic, diagnostic, and prognostic utility.

Current potential pathogenic mechanisms of copper-zinc superoxide dismutase 1 (SOD1) in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease which damages upper and lower motor neurons (UMN and LMN) innervating the muscles of the trunk, extremities, head, neck and face in cerebrum, brain stem and spinal cord, which results in the progressive weakness, atrophy and fasciculation of muscle innervated by the related UMN and LMN, accompanying with the pathological signs leaded by the cortical spinal lateral tract lesion. The pathogenesis about ALS is not fully understood, and no specific drugs are available to cure and prevent the progression of this disease at present. In this review, we reviewed the structure and associated functions of copper-zinc superoxide dismutase 1 (SOD1), discuss why SOD1 is crucial to the pathogenesis of ALS, and outline the pathogenic mechanisms of SOD1 in ALS that have been identified at recent years, including glutamate-related excitotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, oxidative stress, axonal transport disruption, prion-like propagation, and the non-cytologic toxicity of glial cells. This review will help us to deeply understand the current progression in this field of SOD1 pathogenic mechanisms in ALS.

Factors associated with assistive technology prescription and acceptance in motor neurone disease

PURPOSE

The risk of delaying assistive technology (AT) prescription and implementation has significant implications on the safety and quality of life of people with Motor Neurone Disease (PwMND). This study aims to explore the barriers and enablers of AT prescription and implementation identified by PwMND and clinicians.

METHODS

A qualitative study using semi-structured focus groups with clinicians and in-depth interviews with PwMND. Sixteen clinicians and ten PwMND were recruited. Thematic analysis was completed and results were compared and discussed to reach an agreement on the final themes.

RESULTS

Three main factors were identified - PwMND, Clinician and Extrapersonal. For PwMND, personal characteristics, such as mindset, was the strongest enabler and inability to accept diagnosis and AT was the key barrier. For Clinician, communication approach was both the most identified enabler and barrier. For Extrapersonal, the availability of interactive education of AT was the strongest enabler and long wait time was a significant barrier.

CONCLUSION

Our study identified themes that clinicians could have an impact on, such as, providing interactive education, engaging PwMND and their support network, and ongoing upskilling of clinicians working in this field. Themes identified that were beyond the control of clinicians were personal characteristics, acceptance and support networks. It highlights the importance for clinicians to be flexible with their communication approach to accommodate the needs of PwMND in the acceptance of AT.

Motor neurone disease: A point-prevalence study of patient reported symptom prevalence, severity and palliative care needs

BACKGROUND

Motor neurone disease is a rare but debilitating illness with incomplete evidence regarding patients' symptom burden. Palliative care and generalist clinicians are often in-experienced in caring for these patients and assessing their needs.

AIM

To identify the symptom prevalence and severity experienced by patients with motor neurone disease. Secondary objectives were to examine differences in symptom burden and clusters according to phenotype, functional status, palliative care provision and those in their last months of life.

DESIGN

A point prevalence study assessing patient-reported symptoms using a modified IPOS-Neuro assessment tool, incorporating 41 symptom items.

SETTING/PARTICIPANTS

Patients with motor neurone disease attending the State-wide Progressive Neurological Disease Service or inpatient unit at Calvary Health Care Bethlehem, Melbourne Australia, from March to December 2021.

RESULTS

A total of 102 patients participated, the majority diagnosed with lumber-onset (30.4%), bulbar-onset (28.4%) and cervical-onset (25.5%) phenotypes. Patients experienced a median of 17 symptoms (range 2-32) with a median of 3 symptoms rated as severe/overwhelming (range 0-13). Motor and functional symptoms predominated, with differences in symptom clusters present according to phenotype. Patients had a higher number of severe/overwhelming symptoms if they were accessing palliative care services (p = 0.005), in their last 6 months of life (p = 0.003) and experiencing moderate or severe functional impairment (p < 0.001).

CONCLUSIONS

Patients with motor neurone disease report high symptom burden. A validated motor neurone disease-specific symptom assessment tool is needed to accurately assess patients, including important variations in symptom clusters according to phenotype. Further research must focus on evidence-based treatment guidelines for symptoms experienced commonly and severely.

The complexity of multidisciplinary respiratory care in amyotrophic lateral sclerosis

Motor neurone disease/amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder with no known cure, where death is usually secondary to progressive respiratory failure. Assisting people with ALS through their disease journey is complex and supported by clinics that provide comprehensive multidisciplinary care (MDC). This review aims to apply both a respiratory and a complexity lens to the key roles and areas of practice within the MDC model in ALS. Models of noninvasive ventilation care, and considerations in the provision of palliative therapy, respiratory support, and speech and language therapy are discussed. The impact on people living with ALS of both inequitable funding models and the complexity of clinical care decisions are illustrated using case vignettes. Considerations of the impact of emerging antisense and gene modifying therapies on MDC challenges are also highlighted. The review seeks to illustrate how MDC members contribute to collective decision-making in ALS, how the sum of the parts is greater than any individual care component or health professional, and that the MDC per se adds value to the person living with ALS. Through this approach we hope to support clinicians to navigate the space between what are minimum, guideline-driven, standards of care and what excellent, person-centred ALS care that fully embraces complexity could be.

Educational aims

To highlight the complexities surrounding respiratory care in ALS.To alert clinicians to the risk that complexity of ALS care may modify the effectiveness of any specific, evidence-based therapy for ALS.To describe the importance of person-centred care and shared decision-making in optimising care in ALS.

Novel therapeutic approaches to target neurodegeneration

Ageing is the main risk factor common to most primary neurodegenerative disorders. Indeed, age-related brain alterations have been long considered to predispose to neurodegeneration. Although protein misfolding and the accumulation of toxic protein aggregates have been considered as causative events in neurodegeneration, several other biological pathways affected by brain ageing also contribute to pathogenesis. Here, we discuss the evidence showing the involvement of the mechanisms controlling neuronal structure, gene expression, autophagy, cell metabolism and neuroinflammation in the onset and progression of neurodegenerative disorders. Furthermore, we review the therapeutic strategies currently under development or as future approaches designed to normalize these pathways, which may then increase brain resilience to cope with toxic protein species. In addition to therapies targeting the insoluble protein aggregates specifically associated with each neurodegenerative disorder, these novel pharmacological approaches may be part of combined therapies designed to rescue brain function.

Progress, development, and challenges in amyotrophic lateral sclerosis clinical trials

INTRODUCTION

Amyotrophic Lateral Sclerosis (ALS) brings unique challenges to a clinical trial setting, due in part to relatively low disease prevalence coupled with a poor prognosis, in addition to the complexities linked to disease heterogeneity. As critical understanding of the disease develops, particularly in relation to clinical phenotype and the mechanisms of disease progression, so too new concepts evolve in relation to clinical trials, including the advent of precision therapy, targeted to subgroups of ALS patients.

AREAS COVERED

Individualized, or precision medicine in ALS recognizes the heterogeneous nature of the disease and utilizes information such as the clinical phenotype of the disease, clinical biomarkers, and genotyping to promote a tailored approach to treatment. Separate to these considerations, the present review will discuss clinical trial design and how this can be improved to better match patient and investigator needs in ALS clinical trials.

EXPERT OPINION

Precision therapy will promote a more focused treatment approach, with the goal of improving clinical outcomes for ALS patients. An increased community awareness of ALS, coupled with significant industry and philanthropic funding for ALS research, is accelerating this process.

Synucleinopathy in Amyotrophic Lateral Sclerosis: A Potential Avenue for Antisense Therapeutics?

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease classified as both a neurodegenerative and neuromuscular disorder. With a complex aetiology and no current cure for ALS, broadening the understanding of disease pathology and therapeutic avenues is required to progress with patient care. Alpha-synuclein (αSyn) is a hallmark for disease in neurodegenerative disorders, such as Parkinson's disease, Lewy body dementia, and multiple system atrophy. A growing body of evidence now suggests that αSyn may also play a pathological role in ALS, with αSyn-positive Lewy bodies co-aggregating alongside known ALS pathogenic proteins, such as SOD1 and TDP-43. This review endeavours to capture the scope of literature regarding the aetiology and development of ALS and its commonalities with "synucleinopathy disorders". We will discuss the involvement of αSyn in ALS and motor neuron disease pathology, and the current theories and strategies for therapeutics in ALS treatment, as well as those targeting αSyn for synucleinopathies, with a core focus on small molecule RNA technologies.

Genetic testing in motor neurone disease

A minority (10%-15%) of cases of amyotrophic lateral sclerosis (ALS), the most common form of motor neurone disease (MND), are currently attributable to pathological variants in a single identifiable gene. With the emergence of new therapies targeting specific genetic subtypes of ALS, there is an increasing role for routine genetic testing for all those with a definite diagnosis. However, potential harm to both affected individuals and particularly to asymptomatic relatives can arise from the indiscriminate use of genetic screening, not least because of uncertainties around incomplete penetrance and variants of unknown significance. The most common hereditary cause of ALS, an intronic hexanucleotide repeat expansion in C9ORF72, may be associated with frontotemporal dementia independently within the same pedigree. The boundary of what constitutes a possible family history of MND has therefore extended to include dementia and associated psychiatric presentations. Notwithstanding the important role of clinical genetics specialists, all neurologists need a basic understanding of the current place of genetic testing in MND, which holds lessons for other neurological disorders.

MiNDAUS partnership: a roadmap for the cure and management of motor Neurone disease

An innovative approach to patient management, evidence-based policy development, and clinical drug trials is required to provide personalized care and to improve the likelihood of finding an effective treatment for Motor Neurone Disease (MND). The MiNDAus Partnership builds on and extends existing national collaborations in a targeted approach to improve the standard and coordination of care for people living with MND in Australia, and to enhance the prospects of discovering a cure or treatment. Relationships have been developed between leading clinical and research groups as well as patient-centered organizations, care providers, and philanthropy with a shared vision. MiNDAus has established a corporate structure and meets at least biannually to decide on how best to progress research, drug development, and patient management. The key themes are; (i) empowering patients and their family carers to engage in self-management and ensure personalized service provision, treatment, and policy development, (ii) integration of data collection so as to better inform policy development, (iii) unifying patients and carers with advocacy groups, funding bodies, clinicians and academic institutions so as to inform policy development and research, (iv) coordination of research efforts and development of standardized national infrastructure for conducting innovative clinical MND trials that can be harmonized within Australia and with international trials consortia. Such a collaborative approach is required across stakeholders in order to develop innovative management guidelines, underpinned by necessary and evidence-based policy change recommendations, which, will ensure the best patient care until a cure is discovered.

Sex-dependent effects of amyloid precursor-like protein 2 in the SOD1-G37R transgenic mouse model of MND

Motor neurone disease (MND) is a neurodegenerative disorder characterised by progressive destruction of motor neurons, muscle paralysis and death. The amyloid precursor protein (APP) is highly expressed in the central nervous system and has been shown to modulate disease outcomes in MND. APP is part of a gene family that includes the amyloid precursor-like protein 1 (APLP1) and 2 (APLP2) genes. In the present study, we investigated the role of APLP2 in MND through the examination of human spinal cord tissue and by crossing APLP2 knockout mice with the superoxide dismutase 1 (SOD1-G37R) transgenic mouse model of MND. We found the expression of APLP2 is elevated in the spinal cord from human cases of MND and that this feature of the human disease is reproduced in SOD1-G37R mice at the End-stage of their MND-like phenotype progression. APLP2 deletion in SOD1-G37R mice significantly delayed disease progression and increased the survival of female SOD1-G37R mice. Molecular and biochemical analysis showed female SOD1-G37R:APLP2-/- mice displayed improved innervation of the neuromuscular junction, ameliorated atrophy of muscle fibres with increased APP protein expression levels in the gastrocnemius muscle. These results indicate a sex-dependent role for APLP2 in mutant SOD1-mediated MND and further support the APP family as a potential target for further investigation into the cause and regulation of MND.

Cortical Excitability across the ALS Clinical Motor Phenotypes

Amyotrophic lateral sclerosis (ALS) is characterized by its marked clinical heterogeneity. Although the coexistence of upper and lower motor neuron signs is a common clinical feature for most patients, there is a wide range of atypical motor presentations and clinical trajectories, implying a heterogeneity of underlying pathogenic mechanisms. Corticomotoneuronal dysfunction is increasingly postulated as the harbinger of clinical disease, and neurophysiological exploration of the motor cortex in vivo using transcranial magnetic stimulation (TMS) has suggested that motor cortical hyperexcitability may be a critical pathogenic factor linked to clinical features and survival. Region-specific selective vulnerability at the level of the motor cortex may drive the observed differences of clinical presentation across the ALS motor phenotypes, and thus, further understanding of phenotypic variability in relation to cortical dysfunction may serve as an important guide to underlying disease mechanisms. This review article analyses the cortical excitability profiles across the clinical motor phenotypes, as assessed using TMS, and explores this relationship to clinical patterns and survival. This understanding will remain essential to unravelling central disease pathophysiology and for the development of specific treatment targets across the ALS clinical motor phenotypes.

A qualitative meta-synthesis of evidence (meta-ethnography) exploring the personal experiences of gastrostomy tube in neurodegenerative diseases: a case of motor neurone disease

PURPOSE

The lived experiences of a gastrostomy tube (GT) in adults with neurodegenerative diseases (NDDs) are not well understood. The aim of this qualitative meta-synthesis was to review and synthesise the available evidence to inform clinical practice and identify research gaps.

METHODS

Meta-ethnographic synthesis of qualitative studies was conducted with systematic searching of eight databases from inception to March 2021. Qualitative studies reporting personal experiences of GTs in adults with NDDs were identified. New theories were developed during translation of concepts from each study and combined as a "line-of-argument" synthesis. Patient and public involvement was incorporated as two of the authors are living with an NDD and a GT.

RESULTS AND CONCLUSIONS

Of 2863 unique records identified, only nine fulfilled the review criteria. All studies recruited participants with motor neurone disease (MND); no other NDDs were represented. Two main themes emerged: decision making and living with GT. Decision making was the predominant theme and data regarding living with GT were sparse. There is limited research on the lived experience of a GT in adults with NDDs. The lived experience of GT in MND is complex and individualised. Future research is indicated to inform clinical practice.Implications for rehabilitationEvidence related to the lived experiences of gastrostomy tube (GT) in neurodegenerative diseases (NDDs) is lacking especially in relation to the time after GT insertion.Decision making in relation to GT is a complex and individualised psychological process for some people, while others perceive no decisional conflict.Support from healthcare professionals is crucial during the decision-making time and should not cease after GT insertion.Support from healthcare professionals can help resolve any clinical complications and also incorporate GT into everyday routines.Healthcare professionals should be aware that their views on the benefits and problems related to GT may differ to those of individuals with a NDD.

Diagnostic Utility of Gold Coast Criteria in Amyotrophic Lateral Sclerosis

OBJECTIVE

The diagnosis of amyotrophic lateral sclerosis (ALS) remains problematic, with current diagnostic criteria (revised El Escorial [rEEC] and Awaji) being complex and prone to error. Consequently, the diagnostic utility of the recently proposed Gold Coast criteria was determined in ALS.

METHODS

We retrospectively reviewed 506 patients (302 males, 204 females) to compare the diagnostic accuracy of the Gold Coast criteria to that of the Awaji and rEEC criteria (defined by the proportion of patients categorized as definite, probable, or possible ALS) in accordance with standards of reporting of diagnostic accuracy criteria.

RESULTS

The sensitivity of Gold Coast criteria (92%, 95% confidence interval [CI] = 88.7-94.6%) was comparable to that of Awaji (90.3%, 95% CI = 86.69-93.2%) and rEEC (88.6, 95% CI = 84.8-91.7%) criteria. Additionally, the Gold Coast criteria sensitivity was maintained across different subgroups, defined by site of onset, disease duration, and functional disability. In atypical ALS phenotypes, the Gold Coast criteria exhibited greater sensitivity and specificity.

INTERPRETATION

The present study established the diagnostic utility of the Gold Coast criteria in ALS, with benefits evident in bulbar and limb onset disease patients, as well as atypical phenotypes. The Gold Coast criteria should be considered in clinical practice and therapeutic trials. ANN NEUROL 2021;89:979-986.

Cortical inexcitability defines an adverse clinical profile in amyotrophic lateral sclerosis

Background and purpose

In amyotrophic lateral sclerosis, studies using threshold‐tracking transcranial magnetic stimulation (TMS) have identified corticomotoneuronal dysfunction as a key pathogenic mechanism. Some patients, however, display no motor response at maximal TMS intensities, termed here an ‘inexcitable’ motor cortex. The extent to which this cortical difference impacts clinical outcomes remains unclear. The aim of this study was to determine the clinical profile of patients with inexcitability to TMS.

Methods

Motor cortex excitability was evaluated using TMS. Patients in whom a motor evoked potential could not be recorded in one or more limbs at maximal TMS intensities were classified as four‐limb or partially inexcitable. Demographic information, clinical variables and survival data were analysed.

Results

From 133 patients, 40 were identified with inexcitability. Patients with four‐limb inexcitability were younger (P = 0.03) and had lower‐limb disease onset (64%), greater functional disability (P < 0.001) and faster disease progression (P = 0.02), particularly if inexcitability developed within 1 year of symptoms (P < 0.01). Patients with partial inexcitability had higher resting motor thresholds compared to the excitable cohort (P < 0.01), but averaged short‐interval intracortical inhibition was similar (P = 0.5). Mean survival was reduced if inexcitability involved all limbs within 12 months of symptom onset (P = 0.04).

Conclusion

Amyotrophic lateral sclerosis patients with inexcitability of all four limbs to TMS have a distinct clinical profile of younger age and lower‐limb onset. Importantly, these patients display a more malignant disease trajectory, with faster progression, greater functional disability and reduced survival when occurring in early disease. This measure may provide an important prognostic marker in amyotrophic lateral sclerosis.

The Impact of Next-Generation Sequencing on the Diagnosis, Treatment, and Prevention of Hereditary Neuromuscular Disorders

The impact of high-throughput sequencing in genetic neuromuscular disorders cannot be overstated. The ability to rapidly and affordably sequence multiple genes simultaneously has enabled a second golden age of Mendelian disease gene discovery, with flow-on impacts for rapid genetic diagnosis, evidence-based treatment, tailored therapy development, carrier-screening, and prevention of disease recurrence in families. However, there are likely many more neuromuscular disease genes and mechanisms to be discovered. Many patients and families remain without a molecular diagnosis following targeted panel sequencing, clinical exome sequencing, or even genome sequencing. Here we review how massively parallel, or next-generation, sequencing has changed the field of genetic neuromuscular disorders, and anticipate future benefits of recent technological innovations such as RNA-seq implementation and detection of tandem repeat expansions from short-read sequencing.

Phase 2 randomized placebo controlled double blind study to assess the efficacy and safety of tecfidera in patients with amyotrophic lateral sclerosis (TEALS Study): Study protocol clinical trial (SPIRIT Compliant)

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disorder of the human motor system. Neuroinflammation appears to be an important modulator of disease progression in ALS. Specifically, reduction of regulatory T cell (Treg) levels, along with an increase in pro-inflammatory effector T cells, macrophage activation and upregulation of co-stimulatory pathways have all been associated with a rapid disease course in ALS. Autologous infusion of expanded Tregs into sporadic ALS patients, resulted in greater suppressive function, slowing of disease progression and stabilization of respiratory function. Tecfidera (dimethyl fumarate) increases the ratio of anti-inflammatory (Treg) to proinflammatory T-cells in patients with relapsing remitting multiple sclerosis and rebalances the regulatory: inflammatory axis towards a neuroprotective phenotype. Consequently, the aim of this study was to assess the efficacy, safety, and tolerability of Tecfidera in sporadic ALS.

METHODS

The study is an investigator led Phase 2 multi-center, randomized, placebo controlled, double blind clinical trial assessing the efficacy and safety of Tecfidera in patients with sporadic ALS. The study duration is 40 weeks, with a 36-week study period and end of study visit occurring at 40 weeks or at early termination/withdrawal from study. The TEALS study has been registered with the Australian and New Zealand Clinical Trials registry (ANZCTR) under the trials registration number ACTRN12618000534280 and has been approved by the Human Research Ethics Committee and Research Governance Office at the lead site (Westmead Hospital) with the ethics number HREC/17/WMEAD/353. The participating sites have obtained site specific ethics and governance approvals from the local institution.

RESULTS

The primary endpoint is slowing of disease progression as reflected by the differences in the ALS Functional Rating Score-Revised (ALSFRS-R) score at Week 36. The secondary endpoints will include effects in survival, lower motor neuron function, respiratory function, quality of life and safety.

CONCLUSION

This Phase 2 multi-center, randomized, placebo controlled, double blind clinical trial will provide evidence of efficacy and safety of Tecfidera in sporadic ALS.

Structural Variants May Be a Source of Missing Heritability in sALS

The underlying genetic and molecular mechanisms that drive amyotrophic lateral sclerosis (ALS) remain poorly understood. Structural variants within the genome can play a significant role in neurodegenerative disease risk, such as the repeat expansion in C9orf72 and the tri-nucleotide repeat in ATXN2, both of which are associated with familial and sporadic ALS. Many such structural variants reside in uncharacterized regions of the human genome, and have been under studied. Therefore, characterization of structural variants located in and around genes associated with ALS could provide insight into disease pathogenesis, and lead to the discovery of highly informative genetic tools for stratification in clinical trials. Such genomic variants may provide a deeper understanding of how gene expression can affect disease etiology, disease severity and trajectory, patient response to treatment, and may hold the key to understanding the genetics of sporadic ALS. This article outlines the current understanding of amyotrophic lateral sclerosis genetics and how structural variations may underpin some of the missing heritability of this disease.

Pathophysiology and Diagnosis of ALS: Insights from Advances in Neurophysiological Techniques

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal neurodegenerative disorder of the motor neurons, characterized by focal onset of muscle weakness and incessant disease progression. While the presence of concomitant upper and lower motor neuron signs has been recognized as a pathognomonic feature of ALS, the pathogenic importance of upper motor neuron dysfunction has only been recently described. Specifically, transcranial magnetic stimulation (TMS) techniques have established cortical hyperexcitability as an important pathogenic mechanism in ALS, correlating with neurodegeneration and disease spread. Separately, ALS exhibits a heterogeneous clinical phenotype that may lead to misdiagnosis, particularly in the early stages of the disease process. Cortical hyperexcitability was shown to be a robust diagnostic biomarker if ALS, reliably differentiating ALS from neuromuscular mimicking disorders. The present review will provide an overview of key advances in the understanding of ALS pathophysiology and diagnosis, focusing on the importance of cortical hyperexcitability and its relationship to advances in genetic and molecular processes implicated in ALS pathogenesis.

Differentiation of Motor Neuron-Like Cells from Tonsil-Derived Mesenchymal Stem Cells and Their Possible Application to Neuromuscular Junction Formation

Human tonsil-derived mesenchymal stem cells (T-MSCs) are newly identified MSCs and present typical features of MSCs, including having the differentiation capacity into the three germ layers and excellent proliferation capacity. They are easily sourced and are useful for stem cell therapy in various disease states. We previously reported that T-MSCs could be differentiated into skeletal myocytes and Schwann-like cells; therefore, they are a promising candidate for cell therapies for neuromuscular disease. Motor neurons (MNs), which regulate spontaneous behavior, are affected by a wide range of MN diseases (MNDs) for which there are no effective remedies. We investigated the differentiation potential of MN-like cells derived from T-MSCs (T-MSC-MNCs) for application to therapy of MNDs. After the process of MN differentiation, the expression of MN-related markers, including Islet 1, HB9/HLXB9 (HB9), and choline acetyltransferase (ChAT), was increased when compared with undifferentiated T-MSCs. The secretion of acetylcholine to the conditioned medium was significantly increased after MN differentiation. We cocultured T-MSC-MNCs and human skeletal muscle cells, and confirmed the presence of the acetylcholine receptor clusters, which demonstrated the formation of neuromuscular junctions. The potential functional improvements afforded by these T-MSC-MNCs could be useful in the treatment of MNDs caused by genetic mutation, viral infection, or environmental problems.

Amyotrophic Lateral Sclerosis Mortality in the United States, 2011-2014

BACKGROUND

The International Classification of Disease, 10th Revision (ICD-10) did not include a code specific for Amyotrophic lateral sclerosis (ALS) until 2017. Instead, code G12.2 included both ALS and other motor neuron diseases (MND). Our objective was to determine US mortality rates for ALS exclusively by excluding other MND and progressive supranuclear palsy.

METHODS

All mortality data coded as G12.2 under the pre-2017 rubric were obtained for 2011-2014. Deaths without ALS listed in one of the un-coded cause-of-death fields were excluded. ALS death rates per 100,000 persons were age-adjusted to the 2000 US standard population using the direct method.

RESULTS

The proportion of excluded records coded G12.2 but not ALS was 0.21, resulting in 24,328 ALS deaths. The overall age-adjusted mortality rate was 1.70 (95% CI 1.68-1.72). The rate among males was 2.09 (95% CI 2.05-2.12) and females was 1.37 (95% CI 1.35-1.40). The overall rate among whites was 1.84, blacks 1.03, and other races 0.70. For both sexes and all races, the rate increased with age and peaked among 75-79 year-olds. Rates tended to be greater in states at higher latitudes.

CONCLUSIONS

Previous reports of ALS mortality in the United States showed similar age, sex, and race distributions but with greater age-adjusted mortality rates due to the inclusion of other diseases in the case definition. When using ICD-10 data collected prior to 2017, additional review of multiple-cause of death data is required for the accurate estimation of ALS deaths.