Amyotrophic Lateral Sclerosis

Role of copper in central nervous system physiology and pathology

Copper is a transition metal and an essential element for the organism, as alterations in its homeostasis leading to metal accumulation or deficiency have pathological effects in several organs, including the central nervous system. Central copper dysregulations have been evidenced in two genetic disorders characterized by mutations in the copper-ATPases ATP7A and ATP7B, Menkes disease and Wilson's disease, respectively, and also in multifactorial neurological disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis. This review summarizes current knowledge about the role of copper in central nervous system physiology and pathology, reports about unbalances in copper levels and/or distribution under disease, describes relevant animal models for human disorders where copper metabolism genes are dysregulated, and discusses relevant therapeutic approaches modulating copper availability. Overall, alterations in copper metabolism may contribute to the etiology of central nervous system disorders and represent relevant therapeutic targets to restore tissue homeostasis.

Different baseline functional patterns of the frontal cortex in amyotrophic lateral sclerosis patients with Corticospinal tract hyperintensity

Nearly half of the amyotrophic lateral sclerosis (ALS) patients showed hyperintensity of the corticospinal tract (CST+), yet whether brain functional pattern differs between CST+and CST- patients remains obscure. In the current study, 19 ALS CST+, 41 ALS CST- patients and 37 healthy controls (HC) underwent resting state fMRI scans. We estimated local activity and connectivity patterns via the Amplitude of Low Frequency Fluctuations (ALFF) and the Network-Based Statistic (NBS) approaches respectively. The ALS CST+patients did not differ from the CST- patients in amyotrophic lateral sclerosis functional rating scale revised (ALSFRS-R) score and disease duration. ALFF of the superior frontal gyrus (SFG) and the inferior frontal gyrus pars opercularis (OIFG) were highest in the HC and lowest in the ALS CST- patients, resulting in significant group differences (PFWE<0.05). NBS analysis revealed a frontal network consisting of connections between SFG, OIFG, orbital frontal gyrus, middle cingulate cortex and the basal ganglia, which exhibited HC>ALS CST+ > ALS CST- group differences (PFWE=0.037) as well. The ALFF of the OIFG was significantly correlated with ALSFRS-R (R=0.34, P=0.028) and mean connectivity of the frontal network was trend-wise significantly correlated with disease duration (R=-0.31, P=0.052) in the ALS CST- patients. However, these correlations were insignificant in ALS CST+patients (P values > 0.8). In conclusion, The ALS CST+patients exhibited different patterns of baseline functional activity and connectivity in the frontal cortex which may indicate a functional compensatory effect.

Neuroinflammation in amyotrophic lateral sclerosis: pathogenic insights and therapeutic implications

PURPOSE OF REVIEW

Neuroinflammation appears to be an important pathogenic process in amyotrophic lateral sclerosis (ALS). Dysfunction of central immune pathways, including activation of microglia and astrocytes, and peripherally derived immune cells, initiate noncell autonomous inflammatory mechanisms leading to degeneration. Cell autonomous pathways linked to ALS genetic mutations have been recently identified as contributing mechanism for neurodegeneration. The current review provides insights into the pathogenic importance of central and peripheral inflammatory processes in ALS pathogenesis and appraises their potential as therapeutic targets.

RECENT FINDINGS

ALS is a multistep process mediated by a complex interaction of genetic, epigenetic, and environmental factors. Noncell autonomous inflammatory pathways contribute to neurodegeneration in ALS. Activation of microglia and astrocytes, along with central nervous system infiltration of peripherally derived pro-inflammatory innate (NK-cells/monocytes) and adaptive (cell-mediated/humoral) immune cells, are characteristic of ALS. Dysfunction of regulatory T-cells, elevation of pro-inflammatory cytokines and dysbiosis of gut microbiome towards a pro-inflammatory phenotype, have been reported as pathogenic mechanisms in ALS.

SUMMARY

Dysregulation of adaptive and innate immunity is pathogenic in ALS, being associated with greater disease burden, more rapid disease course and reduced survival. Strategies aimed at modulating the pro-inflammatory immune components could be of therapeutic utility.

The genetics of amyotrophic lateral sclerosis

PURPOSE OF REVIEW

Amyotrophic lateral sclerosis (ALS) has a strong genetic basis, but the genetic landscape of ALS appears to be complex. The purpose of this article is to review recent developments in the genetics of ALS.

RECENT FINDINGS

Large-scale genetic studies have uncovered more than 40 genes contributing to ALS susceptibility. Both rare variants with variable effect size and more common variants with small effect size have been identified. The most common ALS genes are C9orf72 , SOD1 , TARDBP and FUS . Some of the causative genes of ALS are shared with frontotemporal dementia, confirming the molecular link between both diseases. Access to diagnostic gene testing for ALS has to improve, as effective gene silencing therapies for some genetic subtypes of ALS are emerging, but there is no consensus about which genes to test for.

SUMMARY

Our knowledge about the genetic basis of ALS has improved and the first effective gene silencing therapies for specific genetic subtypes of ALS are underway. These therapeutic advances underline the need for better access to gene testing for people with ALS. Further research is needed to further map the genetic heterogeneity of ALS and to establish the best strategy for gene testing in a clinical setting.

Poly-GP accumulation due to C9orf72 loss of function induces motor neuron apoptosis through autophagy and mitophagy defects

The GGGGCC hexanucleotide repeat expansion (HRE) of the C9orf72 gene is the most frequent cause of amyotrophic lateral sclerosis (ALS), a devastative neurodegenerative disease characterized by motor neuron degeneration. C9orf72 HRE is associated with lowered levels of C9orf72 expression and its translation results in the production of dipeptide-repeats (DPRs). To recapitulate C9orf72-related ALS disease in vivo, we developed a zebrafish model where we expressed glycine-proline (GP) DPR in a c9orf72 knockdown context. We report that C9orf72 gain- and loss-of-function properties act synergistically to induce motor neuron degeneration and paralysis with poly(GP) accumulating preferentially within motor neurons along with Sqstm1/p62 aggregation indicating macroautophagy/autophagy deficits. Poly(GP) levels were shown to accumulate upon c9orf72 downregulation and were comparable to levels assessed in autopsy samples of patients carrying C9orf72 HRE. Chemical boosting of autophagy using rapamycin or apilimod, is able to rescue motor deficits. Proteomics analysis of zebrafish-purified motor neurons unravels mitochondria dysfunction confirmed through a comparative analysis of previously published C9orf72 iPSC-derived motor neurons. Consistently, 3D-reconstructions of motor neuron demonstrate that poly(GP) aggregates colocalize to mitochondria, thus inducing their elongation and swelling and the failure of their processing by mitophagy, with mitophagy activation through urolithin A preventing locomotor deficits. Finally, we report apoptotic-related increased amounts of cleaved Casp3 (caspase 3, apoptosis-related cysteine peptidase) and rescue of motor neuron degeneration by constitutive inhibition of Casp9 or treatment with decylubiquinone. Here we provide evidence of key pathogenic steps in C9ALS-FTD that can be targeted through pharmacological avenues, thus raising new therapeutic perspectives for ALS patients.

A microRNA diagnostic biomarker for amyotrophic lateral sclerosis

Blood-based diagnostic biomarkers for amyotrophic lateral sclerosis will improve patient outcomes and positively impact novel drug development. Critical to the development of such biomarkers is robust method validation, optimization and replication with adequate sample sizes and neurological disease comparative blood samples. We sought to test an amyotrophic lateral sclerosis biomarker derived from diverse samples to determine if it is disease specific. Extracellular vesicles were extracted from blood plasma obtained from individuals diagnosed with amyotrophic lateral sclerosis, primary lateral sclerosis, Parkinson's disease and healthy controls. Immunoaffinity purification was used to create a neural-enriched extracellular vesicle fraction. MicroRNAs were measured across sample cohorts using real-time polymerase chain reaction. A Kruskal-Wallis test was used to assess differences in plasma microRNAs followed by post hoc Mann-Whitney tests to compare disease groups. Diagnostic accuracy was determined using a machine learning algorithm and a logistic regression model. We identified an eight-microRNA diagnostic signature for blood samples from amyotrophic lateral sclerosis patients with high sensitivity and specificity and an area under the curve calculation of 98% with clear statistical separation from neurological controls. The eight identified microRNAs represent disease-related biological processes consistent with amyotrophic lateral sclerosis. The direction and magnitude of gene fold regulation are consistent across four separate patient cohorts with real-time polymerase chain reaction analyses conducted in two laboratories from diverse samples and sample collection procedures. We propose that this diagnostic signature could be an aid to neurologists to supplement current clinical metrics used to diagnose amyotrophic lateral sclerosis.

Small striatal huntingtin inclusions in patients with motor neuron disease with reduced penetrance and intermediate HTT gene expansions

Short tandem repeat expansions in the human genome are overrepresented in a variety of neurological disorders. It was recently shown that huntingtin (HTT) repeat expansions with full penetrance, i.e. 40 or more CAG repeats, which normally cause Huntington's disease (HD), are overrepresented in patients with amyotrophic lateral sclerosis (ALS). Whether patients carrying HTT repeat expansions with reduced penetrance, (36-39 CAG repeats), or alleles with intermediate penetrance, (27-35 CAG repeats), have an increased risk of ALS has not yet been investigated. Here, we examined the role of HTT repeat expansions in a motor neuron disease (MND) cohort, searched for expanded HTT alleles, and investigated correlations with phenotype and neuropathology. MND patients harboring C9ORF72 hexanucleotide repeat expansions (HREs) were included, to investigate whether HTT repeat expansions were more common in this group. We found a high prevalence of intermediate (range 5.63%-6.61%) and reduced penetrance (range 0.57%-0.66%) HTT gene expansions in this cohort compared to other populations of European ancestry, but no differences between the MND cohort and the control cohort were observed, regardless of C9ORF72HRE status. Upon autopsy of three patients with intermediate or reduced penetrance HTT alleles, huntingtin inclusions were observed in the caudate nucleus and frontal lobe, but no significant somatic mosaicism was detected in different parts of the nervous system. Thus, we demonstrate, for the first time, huntingtin inclusions in individuals with MND and intermediate and reduced penetrance HTT repeat expansions but more clinicopathological investigations are needed to further understand the impact of HTT gene expansion-related pleiotropy.

Nrf2 pathways in neuroprotection: Alleviating mitochondrial dysfunction and cognitive impairment in aging

Mitochondrial dysfunction and cognitive impairment are widespread phenomena among the elderly, being crucial factors that contribute to neurodegenerative diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important regulator of cellular defense systems, including that against oxidative stress. As such, increased Nrf2 activity may serve as a strategy to avert mitochondrial dysfunction and cognitive decline. Scientific data on Nrf2-mediated neuroprotection was collected from PubMed, Google Scholar, and Science Direct, specifically addressing mitochondrial dysfunction and cognitive impairment in older people. Search terms included "Nrf2", "mitochondrial dysfunction," "cognitive impairment," and "neuroprotection." Studies focusing on in vitro and in vivo models and clinical investigations were included to review Nrf2's therapeutic potential comprehensively. The relative studies have demonstrated that increased Nrf2 activity could improve mitochondrial performance, decrease oxidative pressure, and mitigate cognitive impairment. To a large extent, this is achieved through the modulation of critical cellular signalling pathways such as the Keap1/Nrf2 pathway, mitochondrial biogenesis, and neuroinflammatory responses. The present review summarizes the recent progress in comprehending the molecular mechanisms regarding the neuroprotective benefits mediated by Nrf2 through its substantial role against mitochondrial dysfunction and cognitive impairment. This review also emphasizes Nrf2-target pathways and their contribution to cognitive function improvement and rescue from mitochondria-related abnormalities as treatment strategies for neurodegenerative diseases that often affect elderly individuals.

TwinF interface inhibitor FP802 prevents retinal ganglion cell loss in a mouse model of amyotrophic lateral sclerosis

Motor neuron loss is well recognized in amyotrophic lateral sclerosis (ALS), but research on retinal ganglion cells (RGCs) is limited. Ocular symptoms are generally not considered classic ALS symptoms, although RGCs and spinal motor neurons share certain cell pathologies, including hallmark signs of glutamate neurotoxicity, which may be triggered by activation of extrasynaptic NMDA receptors (NMDARs). To explore potential novel strategies to prevent ALS-associated death of RGCs, we utilized inhibition of the TwinF interface, a new pharmacological principle that detoxifies extrasynaptic NMDARs by disrupting the NMDAR/TRPM4 death signaling complex. Using the ALS mouse model SOD1G93A, we found that the small molecule TwinF interface inhibitor FP802 prevents the loss of RGCs, improves pattern electroretinogram (pERG) performance, increases the retinal expression of Bdnf, and restores the retinal expression of the immediate early genes, Inhibin beta A and Npas4. Thus, FP802 not only prevents, as recently described, death of spinal motor neurons in SOD1G93A mice, but it also mitigates ALS-associated retinal damage. TwinF interface inhibitors have great potential for alleviating neuro-ophthalmologic symptoms in ALS patients and offer a promising new avenue for therapeutic intervention.

Unveiling therapeutic biomarkers and druggable targets in ALS: An integrative microarray analysis, molecular docking, and structural dynamic studies

Amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig's disease, is a debilitating neurodegenerative disorder characterized by the progressive degeneration of nerve cells in the brain and spinal cord. Despite extensive research, its precise etiology remains elusive, and early diagnosis is challenging due to the absence of specific tests. This study aimed to identify potential blood-based biomarkers for early ALS detection and monitoring using datasets from whole blood samples (GSE112680) and oligodendrocytes, astrocytes, and fibroblasts (GSE87385) obtained from the NCBI-GEO repository. Through bioinformatics analysis, including protein-protein interactions and molecular pathway analyses, we identified differentially expressed genes (DEGs) associated with ALS. Notably, ALS2, ADH7, ALDH8A1, ALDH3B1, ABHD2, ABHD17B, ABHD12, ABHD13, PGAM2, AURKB, ANAPC11, VAPA, UNC45B, and TNNT2 emerged as top-ranked DEGs, implicated in drug metabolism, protein depalmytilation, and the AKT/mTOR signaling pathways. Among these, AurKB established as a potential therapeutic biomarker with relevance to various neurological conditions. Consequently, AurKB was selected for identifying potential therapeutic molecules and utilized for in silico structural characterization studies. Exploration of the IMPATT database led to the discovery of a lead compound similar to Fostamatinib, currently used for AurKB. Initial molecular docking and MMGBSA-based binding energy analysis were followed by molecular dynamics simulation (MDS) and free energy landscape (FEL) analysis to validate the ligand's binding efficacy and understand dynamic processes within the biological system. The identified potential biomarkers and lead molecule provide novel insights into the correlation between blood cell transcripts and ALS pathology, paving the way for blood-based diagnostic tools for early ALS detection and ongoing disease monitoring.

Cognitive deficits in ALS patients with SOD1 mutations

OBJECTIVE

Cognitive decline is common in patients with amyotrophic lateral sclerosis (ALS), especially in carriers of the mutation C9ORF72HRE. However, cognitive impairment is poorly understood in carriers of mutations in other genes causing ALS. We performed a comprehensive neuropsychological testing in patients with mutations in the SOD1 (mSOD1) gene.

METHODS

We examined 5 cognitive domains in 48 symptomatic patients with either hereditary or sporadic ALS. These were compared with 37 matched controls.

RESULTS

Carriers of SOD1-mutations and sporadic ALS had circumscribed deficits, but in a pattern different from C9ORF72HRE. All groups had deficits in working memory, although mSOD1-carriers significantly outperform sporadic ALS and C9ORF72HRE in an attention-driven visuospatial task involving copying a complex figure. Carriers of the D90A-SOD1 mutation overall performed as well as or better than carriers of other SOD1-mutations, except complex working memory. Bayesian analyses suggest (with evidence of moderate strength) that tasks involving the language domain did not differ between controls, mSOD1 and sporadic ALS.

CONCLUSION

Distinct cognitive impairments are prevalent in different ALS-syndromes and vary in patients with different pathogenic SOD1 mutations. The type and degree of impairment differed depending on genotype and was significantly least pronounced in patients homozygous for the D90A SOD1 mutation. The presence of cognitive deficits may influence optimal clinical management and intervention. We propose that cognitive assessment should be included in the routine examination of new patients suspected of ALS. Neuropsychological assessment is an under-recognized outcome parameter in clinical drug trials.

Experimental Cell Models for Investigating Neurodegenerative Diseases

Experimental models play a pivotal role in biomedical research, facilitating the understanding of disease mechanisms and the development of novel therapeutics. This is particularly true for neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and motor neuron disease, which present complex challenges for research and therapy development. In this work, we review the recent literature about experimental models and motor neuron disease. We identified three main categories of models that are highly studied by scientists. In fact, experimental models for investigating these diseases encompass a variety of approaches, including modeling the patient's cell culture, patient-derived induced pluripotent stem cells, and organoids. Each model offers unique advantages and limitations, providing researchers with a range of tools to address complex biological questions. Here, we discuss the characteristics, applications, and recent advancements in terms of each model system, highlighting their contributions to advancing biomedical knowledge and translational research.

ALS-associated C21ORF2 variant disrupts DNA damage repair, mitochondrial metabolism, neuronal excitability and NEK1 levels in human motor neurons

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease leading to motor neuron loss. Currently mutations in > 40 genes have been linked to ALS, but the contribution of many genes and genetic mutations to the ALS pathogenic process remains poorly understood. Therefore, we first performed comparative interactome analyses of five recently discovered ALS-associated proteins (C21ORF2, KIF5A, NEK1, TBK1, and TUBA4A) which highlighted many novel binding partners, and both unique and shared interactors. The analysis further identified C21ORF2 as a strongly connected protein. The role of C21ORF2 in neurons and in the nervous system, and of ALS-associated C21ORF2 variants is largely unknown. Therefore, we combined human iPSC-derived motor neurons with other models and different molecular cell biological approaches to characterize the potential pathogenic effects of C21ORF2 mutations in ALS. First, our data show C21ORF2 expression in ALS-relevant mouse and human neurons, such as spinal and cortical motor neurons. Further, the prominent ALS-associated variant C21ORF2-V58L caused increased apoptosis in mouse neurons and movement defects in zebrafish embryos. iPSC-derived motor neurons from C21ORF2-V58L-ALS patients, but not isogenic controls, show increased apoptosis, and changes in DNA damage response, mitochondria and neuronal excitability. In addition, C21ORF2-V58L induced post-transcriptional downregulation of NEK1, an ALS-associated protein implicated in apoptosis and DDR. In all, our study defines the pathogenic molecular and cellular effects of ALS-associated C21ORF2 mutations and implicates impaired post-transcriptional regulation of NEK1 downstream of mutant C21ORF72 in ALS.

Loss-of-function variants in RNA binding motif protein X-linked induce neuronal defects contributing to amyotrophic lateral sclerosis pathogenesis

Despite being one of the most prevalent RNA modifications, the role of N6-methyladenosine (m6A) in amyotrophic lateral sclerosis (ALS) remains ambiguous. In this investigation, we explore the contribution of genetic defects of m6A-related genes to ALS pathogenesis. We scrutinized the mutation landscape of m6A genes through a comprehensive analysis of whole-exome sequencing cohorts, encompassing 508 ALS patients and 1660 population-matched controls. Our findings reveal a noteworthy enrichment of RNA binding motif protein X-linked (RBMX) variants among ALS patients, with a significant correlation between pathogenic m6A variants and adverse clinical outcomes. Furthermore, Rbmx knockdown in NSC-34 cells overexpressing mutant TDP43Q331K results in cell death mediated by an augmented p53 response. Similarly, RBMX knockdown in ALS motor neurons derived from induced pluripotent stem cells (iPSCs) manifests morphological defects and activation of the p53 pathway. Transcriptional analysis using publicly available single-cell sequencing data from the primary motor cortex indicates that RBMX-regulated genes selectively influence excitatory neurons and exhibit enrichment in ALS-implicated pathways. Through integrated analyses, our study underscores the emerging roles played by RBMX in ALS, suggesting a potential nexus between the disease and dysregulated m6A-mediated mRNA metabolism.

Discovery and Exploration of Lipid-Modifying Drug Targets for ALS by Mendelian Randomization

Observational studies have faced challenges in identifying replicable causes for amyotrophic lateral sclerosis (ALS). To address this, we employed an unbiased and data-driven approach to discover and explore potential causal exposures using two-sample Mendelian randomization (MR) analyses. In the phenotype discovery stage, we assessed 3948 environmental exposures from the UK Biobank and utilized ALS summary statistics (Europeans, 20,806 cases, 59,804 controls) as the outcome within a phenome-wide MR pipeline. Through a range of sensitivity analyses, two medication traits were identified to be protective for ALS. In the target exploration stage, we further conducted drug target MR analyses using the latest and trans-ethnic summary data on lipid-related traits and ALS (Europeans, 27,205 cases, 110,881 controls; East Asians, 1234 cases, 2850 controls). Our aim was to explore potential causal drug targets through six lipid-modifying effects. These comprehensive analyses revealed significant findings. Specifically, "cholesterol-lowering medication" and "atorvastatin" survived predefined criteria in the phenotype discovery stage and exhibited a protective effect on ALS. Further in the target exploration stage, we demonstrated that the therapeutic effect of APOB through LDL-lowering was associated with reduced ALS liability in Europeans (OR = 0.835, P = 5.61E - 5). Additionally, the therapeutic effect of APOA1 and LDLR through TC-lowering was associated with reduced ALS liability in East Asians (APOA1, OR = 0.859, P = 5.38E - 4; LDLR, OR = 0.910, P = 2.73E - 5). Overall, we propose potential protective effects of cholesterol-lowering drugs or statins on ALS risk from thousands of exposures. Our research also suggests APOB, APOA1, and LDLR as novel therapeutic targets for ALS and supports their potential protective mechanisms may be mediated by LDL-lowering or TC-lowering effects.

Montelukast improves disease outcome in SOD1G93A female mice by counteracting oligodendrocyte dysfunction and aberrant glial reactivity

BACKGROUND AND PURPOSE

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive motor neuron (MN) loss and consequent muscle atrophy, for which no effective therapies are available. Recent findings reveal that disease progression is fuelled by early aberrant neuroinflammation and the loss of oligodendrocytes with neuroprotective and remyelinating properties. On this basis, pharmacological interventions capable of restoring a pro-regenerative local milieu and re-establish proper oligodendrocyte functions may be beneficial.

EXPERIMENTAL APPROACH

Here, we evaluated the in vivo therapeutic effects of montelukast (MTK), an antagonist of the oligodendroglial G protein-coupled receptor 17 (GPR17) and of cysteinyl-leukotriene receptor 1 (CysLT1R) receptors on microglia and astrocytes, in the SOD1G93A ALS mouse model. We chronically treated SOD1G93A mice with MTK, starting from the early symptomatic disease stage. Disease progression was assessed by behavioural and immunohistochemical approaches.

KEY RESULTS

Oral MTK treatment significantly extended survival probability, delayed body weight loss and ameliorated motor functionalityonly in female SOD1G93A mice. Noteworthy, MTK significantly restored oligodendrocyte maturation and induced significant changes in the reactive phenotype and morphological features of microglia/macrophages and astrocytes in the spinal cord of female SOD1G93A mice, suggesting enhanced pro-regenerative functions. Importantly, concomitant MN preservation has been detected after MTK administration. No beneficial effects were observed in male mice, highlighting a sex-based difference in the protective activity of MTK.

CONCLUSIONS AND IMPLICATIONS

Our results provide the first preclinical evidence indicating that repurposing of MTK, a safe and marketed anti-asthmatic drug, may be a promising sex-specific strategy for personalized ALS treatment.

Investigating the impact of socioeconomic status on amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the gradual death of motor neurons in the brain and spinal cord, leading to fatal paralysis. Socioeconomic status (SES) is a measure of an individual's shared economic and social status, which has been shown to have an association with health outcomes. Understanding the impact of SES on health conditions is crucial, as it can influence and be influenced by health-related variables. The role of socioeconomic status in influencing the risk and progression of ALS has not been established, and understanding the various factors that impact ALS is important in developing strategies for treatment and prevention. To investigate this relationship, we recruited 413 participants with definite, probable, or possible ALS according to the El Escorial criteria, from three tertiary centers in London, Sheffield, and Birmingham. Logistic regression was used to examine the association between case-control status, socioeconomic criteria, and ALS risk. Linear regression was used to examine the association between age of onset and socioeconomic variables. Two sensitivity analyses were performed, one using an alternative occupational classifier, and the other using Mendelian Randomization analysis to examine association. There was no significant relationship between any variables and ALS risk. We found an inverse relationship between mean lifetime salary and age of ALS onset (Beta = -0.157, p = 0.011), but no effect of education or occupation on the age of onset. The finding was confirmed in both sensitivity analyses and in Mendelian Randomization. We find that a higher salary is associated with a younger age of ALS onset taking into account sex, occupation, years of education, and clinical presentation.

ATAXIN-2 intermediate-length polyglutamine expansions elicit ALS-associated metabolic and immune phenotypes

Intermediate-length repeat expansions in ATAXIN-2 (ATXN2) are the strongest genetic risk factor for amyotrophic lateral sclerosis (ALS). At the molecular level, ATXN2 intermediate expansions enhance TDP-43 toxicity and pathology. However, whether this triggers ALS pathogenesis at the cellular and functional level remains unknown. Here, we combine patient-derived and mouse models to dissect the effects of ATXN2 intermediate expansions in an ALS background. iPSC-derived motor neurons from ATXN2-ALS patients show altered stress granules, neurite damage and abnormal electrophysiological properties compared to healthy control and other familial ALS mutations. In TDP-43Tg-ALS mice, ATXN2-Q33 causes reduced motor function, NMJ alterations, neuron degeneration and altered in vitro stress granule dynamics. Furthermore, gene expression changes related to mitochondrial function and inflammatory response are detected and confirmed at the cellular level in mice and human neuron and organoid models. Together, these results define pathogenic defects underlying ATXN2-ALS and provide a framework for future research into ATXN2-dependent pathogenesis and therapy.

ALS-Linked VapB P56S Mutation Alters Neuronal Mitochondrial Turnover at the Synapse

Mitochondrial population maintenance in neurons is essential for neuron function and survival. Contact sites between mitochondria and the endoplasmic reticulum (ER) are poised to regulate mitochondrial homeostasis in neurons. These contact sites can facilitate transfer of calcium and lipids between the organelles and have been shown to regulate aspects of mitochondrial dynamics. Vesicle-associated membrane protein-associated protein B (VapB) is an ER membrane protein present at a subset of ER-mitochondrial contact sites. A proline-to-serine mutation in VapB at amino acid 56 (P56S) correlates with susceptibility to amyotrophic lateral sclerosis (ALS) type 8. Given the relationship between failed mitochondrial health and neurodegenerative disease, we investigated the function of VapB in mitochondrial population maintenance. We demonstrated that transgenic expression of VapBP56S in zebrafish larvae (sex undetermined) increased mitochondrial biogenesis, causing increased mitochondrial population size in the axon terminal. Expression of wild-type VapB did not alter biogenesis but, instead, increased mitophagy in the axon terminal. Using genetic manipulations to independently increase mitochondrial biogenesis, we show that biogenesis is normally balanced by mitophagy to maintain a constant mitochondrial population size. VapBP56S transgenics fail to increase mitophagy to compensate for the increase in mitochondrial biogenesis, suggesting an impaired mitophagic response. Finally, using a synthetic ER-mitochondrial tether, we show that VapB's function in mitochondrial turnover is likely independent of ER-mitochondrial tethering by contact sites. Our findings demonstrate that VapB can control mitochondrial turnover in the axon terminal, and this function is altered by the P56S ALS-linked mutation.

Atomic resolution map of the solvent interactions driving SOD1 unfolding in CAPRIN1 condensates

Biomolecules can be sequestered into membrane-less compartments, referred to as biomolecular condensates. Experimental and computational methods have helped define the physical-chemical properties of condensates. Less is known about how the high macromolecule concentrations in condensed phases contribute "solvent" interactions that can remodel the free-energy landscape of other condensate-resident proteins, altering thermally accessible conformations and, in turn, modulating function. Here, we use solution NMR spectroscopy to obtain atomic resolution insights into the interactions between the immature form of superoxide dismutase 1 (SOD1), which can mislocalize and aggregate in stress granules, and the RNA-binding protein CAPRIN1, a component of stress granules. NMR studies of CAPRIN1:SOD1 interactions, focused on both unfolded and folded SOD1 states in mixed phase and demixed CAPRIN1-based condensates, establish that CAPRIN1 shifts the SOD1 folding equilibrium toward the unfolded state through preferential interactions with the unfolded ensemble, with little change to the structure of the folded conformation. Key contacts between CAPRIN1 and the H80-H120 region of unfolded SOD1 are identified, as well as SOD1 interaction sites near both the arginine-rich and aromatic-rich regions of CAPRIN1. Unfolding of immature SOD1 in the CAPRIN1 condensed phase is shown to be coupled to aggregation, while a more stable zinc-bound, dimeric form of SOD1 is less susceptible to unfolding when solvated by CAPRIN1. Our work underscores the impact of the condensate solvent environment on the conformational states of resident proteins and supports the hypothesis that ALS mutations that decrease metal binding or dimerization function as drivers of aggregation in condensates.

Comparative analysis of neurofilaments and biomarkers of muscular damage in amyotrophic lateral sclerosis

Diagnosis of the fatal neurodegenerative disease amyotrophic lateral sclerosis is challenging. Neurofilaments, indicative of neuronal damage, along with creatine kinase, creatinine, myoglobin, and troponin T, representing muscular damage, have been identified as promising fluid biomarkers. This study aims to comprehensively assess and compare their diagnostic and prognostic potential in a 'real-world' cohort of patients with amyotrophic lateral sclerosis. About 77 patients with amyotrophic lateral sclerosis and its clinical variants, and 26 age- and sex-matched controls with various neuromuscular and neurodegenerative diseases, were retrospectively included in this monocentric, cross-sectional study. Neurofilaments in cerebrospinal fluid and biomarkers of muscular damage in serum were measured and correlated with demographic features, motor function, survival time, clinical phenotypes, and the extent of upper and lower motor neuron involvement. Neurofilament, myoglobin, and troponin T concentrations were higher in patients with amyotrophic lateral sclerosis compared to disease controls. Higher neurofilament levels correlated with lower motor function and faster disease progression rate, while higher creatine kinase and creatinine concentrations were linked to preserved motor function. In contrast, troponin T elevation indicated poorer fine and gross motor functions. Increased neurofilament levels were associated with shorter survival, whereas biomarkers of muscular damage lacked survival correlation. Neurofilament concentrations were higher in classical amyotrophic lateral sclerosis than in progressive muscular atrophy, while myoglobin and troponin T levels were elevated in progressive muscular atrophy compared to primary lateral sclerosis. Neurofilaments were predominantly linked to upper motor neuron involvement. Our findings confirmed the robust diagnostic and prognostic value of neurofilaments in amyotrophic lateral sclerosis. Elevated neurofilament concentrations were associated with higher disease severity, faster disease progression, shorter survival, and predominant upper motor neuron degeneration. Biomarkers of muscular damage were inferior in distinguishing amyotrophic lateral sclerosis from other neuromuscular and neurodegenerative diseases. However, they may serve as complementary biomarkers and support in discriminating clinical variants of amyotrophic lateral sclerosis.

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

OBJECTIVES

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

DESIGN

Systematic review and meta-analyses.

DATA SOURCES

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

ELIGIBILITY CRITERIA

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

DATA EXTRACTION AND SYNTHESIS

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

RESULTS

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

CONCLUSIONS

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

PROSPERO REGISTRATION NUMBER

CRD42021251350.

Low-intensity pulsed ultrasound modulates disease progression in the SOD1G93A mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the progressive loss of motor neurons in the brain and spinal cord, and there are no effective drug treatments. Low-intensity pulsed ultrasound (LIPUS) has garnered attention as a promising noninvasive neuromodulation method. In this study, we investigate its effects on the motor cortex and underlying mechanisms using the SOD1G93A mouse model of ALS. Our results show that LIPUS treatment delays disease onset and prolongs lifespan in ALS mice. LIPUS significantly increases cerebral blood flow in the motor cortex by preserving vascular endothelial cell integrity and increasing microvascular density, which may be mediated via the ion channel TRPV4. RNA sequencing analysis reveals that LIPUS substantially reduces the expression of genes associated with neuroinflammation. These findings suggest that LIPUS applied to the motor cortex may represent a potentially effective therapeutic tool for the treatment of ALS.

Inhibition of glycolytic reprogramming suppresses innate immune-mediated inflammation in experimental amyotrophic lateral sclerosis

BACKGROUND

Innate immune activation has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). However, metabolic pathways that govern this bioenergetically demanding process in ALS remains elusive. Here we investigated whether and how immunometabolic transformation of innate immune cells contributes to disease progression in an experimental model of this neurodegenerative disease.

METHODS

We utilized multidimensional flow cytometry and integrative metabolomics to characterize the immunometabolic phenotype of circulating and spinal cord innate immune cells in the B6SJL-Tg(SOD1*G93A)1Gur/J model of ALS (SOD1-G93A) at various disease stages (before vs. after the onset of motor dysfunction). Behavioral and survival analyses were also conducted to determine the impact of an energy-regulating compound on innate immune cell metabolism, inflammation, and disease development.

RESULTS

Temporally coordinated accumulation of circulating inflammatory Ly6C + monocytes and spinal cord F4/80 + CD45hi infiltrates precedes the onset of motor dysfunction in SOD1-G93A mice. Subsequent metabolomic analysis reveals that this phenomenon is accompanied by glycolytic reprogramming of spinal cord inflammatory CD11b + cells, comprising both resident F4/80 + CD45low microglia and F4/80 + CD45hi infiltrates. Furthermore, pharmacologic inhibition of glycolysis by ZLN005, a small molecule activator of Ppargc1a, restrains inflammatory glycolytic activation of spinal cord CD11b + cells, enhances motor function, and prolongs survival in SOD1-G93A mice.

CONCLUSIONS

These observations suggest that modulation of inflammatory glycolytic reprogramming of innate immune cells may represent a promising therapeutic approach in ALS.

Harnessing transcriptomic signals for amyotrophic lateral sclerosis to identify novel drugs and enhance risk prediction

Introduction

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. This study integrates common genetic association results from the latest ALS genome-wide association study (GWAS) summary statistics with functional genomic annotations with the aim of providing mechanistic insights into ALS risk loci, inferring drug repurposing opportunities, and enhancing prediction of ALS risk and clinical characteristics.

Methods

Genes associated with ALS were identified using GWAS summary statistic methodology including SuSiE SNP-based fine-mapping, and transcriptome- and proteome-wide association study (TWAS/PWAS) analyses. Using several approaches, gene associations were integrated with the DrugTargetor drug-gene interaction database to identify drugs that could be repurposed for the treatment of ALS. Furthermore, ALS gene associations from TWAS were combined with observed blood expression in two external ALS case-control datasets to calculate polytranscriptomic scores and evaluate their utility for prediction of ALS risk and clinical characteristics, including site of onset, age at onset, and survival.

Results

SNP-based fine-mapping, TWAS and PWAS identified 118 genes associated with ALS, with TWAS and PWAS providing novel mechanistic insights. Drug repurposing analyses identified six drugs significantly enriched for interactions with ALS associated genes, though directionality could not be determined. Additionally, drug class enrichment analysis showed gene signatures linked to calcium channel blockers may reduce ALS risk, whereas antiepileptic drugs may increase ALS risk. Across the two observed expression target samples, ALS polytranscriptomic scores significantly predicted ALS risk (R 2 = 5.1 %; p-value = 3.2 × 10-27) and clinical characteristics.

Conclusions

Functionally-informed analyses of ALS GWAS summary statistics identified novel mechanistic insights into ALS aetiology, highlighted several therapeutic research avenues, and enabled statistically significant prediction of ALS risk.

The prion-like effect and prion-like protein targeting strategy in amyotrophic lateral sclerosis

Pathological proteins in amyotrophic lateral sclerosis (ALS), such as superoxide dismutase 1, TAR DNA-binding protein 43, and fused in sarcoma, exhibit a prion-like pattern. All these proteins have a low-complexity domain and seeding activity in cells. In this review, we summarize the studies on the prion-like effect of these proteins and list six prion-like protein targeting strategies that we believe have potential for ALS therapy, including antisense oligonucleotides, antibody-based technology, peptide, protein chaperone, autophagy enhancement, and heteromultivalent compounds. Considering the pathological complexity and heterogeneity of ALS, we believe that the final solution to ALS therapy is most likely to be an individualized cocktail therapy, including clearance of toxicity, blockage of pathological progress, and protection of neurons.

Development and Piloting of a Bereaved Care Partner Survey to Inform Quality Improvement in ALS Supportive Care

OBJECTIVES

Bereaved care partner surveys typically focus on the experience with care in the final days of life. We sought to develop and pilot a novel bereaved care partner survey to understand experiences with ALS supportive care provided throughout the illness and identify opportunities for quality improvement.

METHODS

We developed the survey using a multisite, interdisciplinary consensus process involving ALS and palliative care clinicians as well as patient advocates. We then piloted the survey at a single site via video interviews with care partners of patients who died from ALS between three and 15 months prior. Qualitative findings were analyzed using Rapid Qualitative Analysis.

RESULTS

The survey includes 17 core questions and nine demographic items. Questions inquire about whether the patient and care partner received adequate help with physical symptoms, emotional and practical needs, education about the illness and how to provide hands-on care, preparing for what was to come, and bereavement. They also query whether care was person-centered and consistent with the patient's values and preferences. During the pilot with 18 bereaved care partners, the tool generated detailed feedback about aspects of care to preserve as well as how to improve ALS supportive care.

DISCUSSION

We developed and piloted a bereaved care partner survey to understand and improve the quality of ALS supportive care, which was found to be feasible and acceptable. Next steps include testing it at additional centers in order to generate learnings that can advance ALS supportive care in ways that are meaningful to patients and care partners.

Preservation of Vocal Function in Amyotrophic Lateral Sclerosis (ALS) Patients Following Percutaneous Dilatational Tracheostomy (PDT) and Adjuvant Therapies

The study aimed to evaluate the efficacy of percutaneous dilatational tracheostomy (PDT) combined with adjuvant therapies in preserving vocal function in amyotrophic lateral sclerosis (ALS) patients.

METHODS

We performed a retrospective analysis of 47 ALS patients who underwent PDT at the Rodem Hospital from 2021 to 2023. Post-operatively, these patients were provided with a comprehensive treatment plan that included regenerative injection therapy, low-frequency electrical stimulation, respiratory rehabilitation, and swallowing rehabilitation therapy. Additionally, a balloon reduction program was implemented for effective tracheostomy tube (T-tube) management. The preservation of vocal functions was evaluated 4 weeks following the procedure.

RESULTS

While some patients maintained or slightly improved their ALSFRS-R speech scores, the overall trend indicated a decrease in speech scores post-PDT. This suggests that PDT in combination with adjuvant therapies may not universally improve vocal function, but can help maintain it in certain cases.

CONCLUSIONS

Our findings indicate that PDT combined with mesotherapy, low-frequency electrical stimulation, and swallowing rehabilitation therapy may play a role in maintaining vocal function in limb type ALS patients, though further research is needed to optimize patient management and to validate these results.

Use of the combination of spirometry, arterial blood gas analysis and overnight oximetry to predict the outcomes of patients affected by motor neuron disease: The Milan-Torin respiratory score (Mi-To-RS)

BACKGROUND AND PURPOSE

The use of multiple tests, including spirometry, arterial blood gas (ABG) analysis and overnight oximetry (OvOx), is highly recommended to monitor the respiratory function of patients with motor neuron disease (MND). In this study, we propose a composite score to simplify the respiratory management of MND patients and better stratify their prognosis.

MATERIALS AND METHODS

We screened the clinical charts of 471 non-ventilated MND patients referred to the Neuro-rehabilitation Unit of the San Raffaele Scientific Institute of Milan (January 2001-December 2019), collecting spirometric, ABG and OvOx parameters. To evaluate the prognostic role of each measurement, univariate Cox regression for death/tracheostomy was performed, and the variables associated with survival were selected to design a scoring system. Univariate and multivariate Cox regression analyses were then carried out to evaluate the prognostic role of the score. Finally, results were replicated in an independent cohort from the Turin ALS Center.

RESULTS

The study population included 450 patients. Six measurements were found to be significantly associated with survival and were selected to design a scoring system (maximum score = 8 points). Kaplan-Meier analysis showed significant stratification of survival and time to non-invasive mechanical ventilation adaptation according to score values, and multivariate analysis confirmed the independent effect of the respiratory score on survival of each cohort.

CONCLUSION

Forced vital capacity, ABG and OvOx parameters provide complementary information for the respiratory management and prognosis of MND patients and the combination of these parameters into a single score might help neurologists predict prognosis and guide decisions on the timing of the implementation of different diagnostic or therapeutic approaches.

ALS Identified: two-year findings from a sponsored ALS genetic testing program

OBJECTIVE

To report initial results from the Amyotrophic Lateral Sclerosis (ALS) Identified genetic testing (GT) program on characteristics of individuals tested and frequency of reported disease-causing variants.

METHODS

ALS Identified used the Invitae Amyotrophic Lateral Sclerosis panel (Invitae, San Francisco, CA, USA) to assay 22 ALS-associated genes. Sponsored by Biogen (Cambridge, MA, USA), the program was launched in June 2021 and was available at no charge to individuals ≥18 years in the United States and Puerto Rico with an ALS diagnosis or a known family history of ALS. Deidentified data were available to Biogen.

RESULTS

As of 26 October 2023, 998 healthcare professionals ordered the panel at 681 unique care sites. Of 8054 individuals examined, 7483 (92.9%) were reported to have a clinical diagnosis of ALS, while 571 (7.1%) were asymptomatic relatives. Of the individuals with a clinical ALS diagnosis, 57.7% were male (n = 4319) and 42.3% female (n = 3164). Mean (SD) age at diagnosis is 62 (13) years. Out of the 7483 clinically diagnosed individuals, 1810 (24.2%) showed genetic variations in ALS-associated genes. Among these, 865 individuals (47.8%) carried pathogenic variants, and 44 (2.4%) had likely pathogenic variants, totaling 12.1% of the clinically diagnosed population.

INTERPRETATION

Since 2021 there has been robust uptake and sustained use of the ALS Identified program, one of the largest samples of people with ALS to date across the United States, demonstrating the interest and need for genetic ALS testing.

Genetic and in silico analysis of Indian sporadic young onset patient with amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is an old onset devastating neurodegenerative disorder. Young-onset ALS cases especially sporadic ones who are between 25 and 45 years are rarely affected by the disease. Despite the identification of numerous candidate genes associated with ALS, the etiology of the disease remains elusive due to extreme genetic and phenotypic variability. The advent of affordable whole exome sequencing (WES) has opened new avenues for unraveling the disease's pathophysiology better.

METHODS AND RESULTS

We aimed to determine the genetic basis of an Indian-origin, young onset sporadic ALS patient with very rapid deterioration of the disease course without any cognitive decline who was screened for mutations in major ALS candidate genes by WES. Variants detected were reconfirmed by Sanger sequencing. The clinicopathological features were investigated and two heterozygous missense variants were identified: R452W, not previously associated with ALS, present in one of the four conserved C terminal domains in ANXA11 and R208W in SIGMAR1, respectively. Both of these variants were predicted to be damaging by pathogenicity prediction tools and various in silico methods.

CONCLUSION

Our study revealed two potentially pathogenic variants in two ALS candidate genes. The genetic makeup of ALS patients from India has been the subject of a few prior studies, but none of them examined ANXA11 and SIGMAR1 genes so far. These results establish the framework for additional research into the pathogenic processes behind these variations that result in sporadic ALS disease and further our understanding of the genetic makeup of Indian ALS patients.

Neutrophil-to-lymphocyte ratio at diagnosis as a biomarker for survival of amyotrophic lateral sclerosis

INTRODUCTION

The neutrophil-to-lymphocyte ratio (NLR) has previously been reported to be associated with survival in ALS. To provide further information about the role of NLR as a biomarker in ALS, we performed a systematic review, analyzed data from our local cohort of ALS subjects and performed a meta-analysis.

METHODS

(1) The systematic review used established methods. (2) Using data from our cohort of subjects, we analyzed the association of NLR with survival. (3) Meta-analysis was performed using previous studies and our local data.

RESULTS

(1) In the systematic review, higher NLR was associated with shorter survival in all studies. (2) In our subjects, survival was significantly shorter in patients in the highest NLR groups. (3) Meta-analysis showed subjects with highest NLR tertile or with NLR >3 had significantly shorter survival than other subjects.

DISCUSSION

This study supports NLR as a biomarker in ALS; high NLR is associated with poor survival.

Peripheral immunity relate to disease progression and prognosis in amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Abnormalities in the peripheral immune system in ALS have been paid attention; however, the results of changes in peripheral immune parameters were inconsistent.

METHODS

A total of 1109 ALS patients were enrolled in the study. All patients received clinical evaluation and peripheral immune parameters measurement. The outcomes were analyzed by correlation analysis, multiple linear regression and cox survival analysis.

RESULTS

We found that ALS patients had significantly higher percentage of CD4+ T cells (39.3 vs. 37.1%, p < 0.001) and CD4+/CD8+ ratio (1.88 vs. 1.72, p = 0.011), significantly lower IgG (11.73 vs.12.82, p < 0.001) and IgA (2130.70 vs. 2284.8, p = 0.013) compared with the health controls. In the multivariate linear model, we found that each increase of 1.262, 0.278, and 4.44E-4 in ALSFRS-R scores were significantly associated with each increment of lymphocyte count, IgG, and IgA, respectively. However, each decrease of 0.341, 0.068, and 0.682 in ALSFRS-R score was associated with each increment in neutrophils, CD4+ T cells, and CD4+/CD8+ ratio, respectively. Cox survival regression analysis showed that the death risk of ALS patients was related to the levels of C3 (HR 0.592, 95% CI 0.361-0.973).

CONCLUSION

We found that there were differences in peripheral immune parameters of ALS patients with the severity of the disease, especially neutrophil, lymphocyte, CD4+ T, and IgG; C3 is an independent predictor of survival in ALS patients. More studies are needed to elucidate the mechanisms associated with altered immune parameters in ALS.

Genotype-phenotype association and functional analysis of hnRNPA1 mutations in amyotrophic lateral sclerosis

BACKGROUND

Pathogenic variants in hnRNPA1 have been reported in amyotrophic lateral sclerosis (ALS) patients. However, studies on hnRNPA1 mutant spectrum and pathogenicity of variants were rare.

METHODS

We performed whole exome sequencing of ALS-associated genes and subsequent verification of rare variants in hnRNPA1 in our ALS patients. The hnRNPA1 mutations reported in literature were reviewed and combined with our results to determine the genotype-phenotype relationship. Functional analysis of the novel variant p.G195A was performed in vitro by transfection of mutant hnRNPA1 into 293T cell.

RESULTS

Among 207 ALS patients recruited, 3 rare hnRNPA1 variants were identified (mutant frequency 1.45%), including two recurrent mutations (p.P340S and p.G283R), and a novel rare variant p.G195A. In combination with previous reports, there are 27 ALS patients with 15 hnRNPA1 mutations identified. Disease onset age was 47.90 ± 1.52 years with predominant limb onset. The p.P340S mutation caused flail arm syndrome (FAS) in two independent families with extended life expectancy. The newly identified p.G195A mutation, lying at the start of the PrLD ("prion-like" domain)/LCD (low-complexity domain), causes local structural changes in 3D protein prediction. Upon sodium arsenite exposure, mutant hnRNPA1 retained in the nucleus but deficit of cytoplasmic G3BP1-positive stress granule clearance was observed. This is different from the p.P340S mutation which caused both cytoplasmic translocation and stress granule formation. No cytoplasmic TDP-43 translocation was observed.

CONCLUSION

Mutations in hnRNPA1 are overall minor in ALS patients. The p.P340S mutation is associated with manifestation of FAS. Mutations in LCD of hnRNPA1 cause stress granule misprocessing.

Spatial enrichment and genomic analyses reveal the link of NOMO1 with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a severe motor neuron disease with uncertain genetic predisposition in most sporadic cases. The spatial architecture of cell types and gene expression are the basis of cell-cell interactions, biological function and disease pathology, but are not well investigated in the human motor cortex, a key ALS-relevant brain region. Recent studies indicated single nucleus transcriptomic features of motor neuron vulnerability in ALS motor cortex. However, the brain regional vulnerability of ALS-associated genes and the genetic link between region-specific genes and ALS risk remain largely unclear. Here, we developed an entropy-weighted differential gene expression matrix-based tool (SpatialE) to identify the spatial enrichment of gene sets in spatial transcriptomics. We benchmarked SpatialE against another enrichment tool (multimodal intersection analysis) using spatial transcriptomics data from both human and mouse brain tissues. To investigate regional vulnerability, we analysed three human motor cortex and two dorsolateral prefrontal cortex tissues for spatial enrichment of ALS-associated genes. We also used Cell2location to estimate the abundance of cell types in ALS-related cortex layers. To dissect the link of regionally expressed genes and ALS risk, we performed burden analyses of rare loss-of-function variants detected by whole-genome sequencing in ALS patients and controls, then analysed differential gene expression in the TargetALS RNA-sequencing dataset. SpatialE showed more accurate and specific spatial enrichment of regional cell type markers than multimodal intersection analysis in both mouse brain and human dorsolateral prefrontal cortex. Spatial transcriptomic analyses of human motor cortex showed heterogeneous cell types and spatial gene expression profiles. We found that 260 manually curated ALS-associated genes are significantly enriched in layer 5 of the motor cortex, with abundant expression of upper motor neurons and layer 5 excitatory neurons. Burden analyses of rare loss-of-function variants in Layer 5-associated genes nominated NOMO1 as a novel ALS-associated gene in a combined sample set of 6814 ALS patients and 3324 controls (P = 0.029). Gene expression analyses in CNS tissues revealed downregulation of NOMO1 in ALS, which is consistent with a loss-of-function disease mechanism. In conclusion, our integrated spatial transcriptomics and genomic analyses identified regional brain vulnerability in ALS and the association of a layer 5 gene (NOMO1) with ALS risk.

Central venous catheter-related thrombosis in patients with amyotrophic lateral sclerosis

BACKGROUND

Central venous catheterization may be required in patients with amyotrophic lateral sclerosis (ALS) for parenteral nutrition, antibiotic treatment, or blood sampling. Different venous access devices can be taken into consideration-centrally inserted central catheters (CICC), peripherally inserted central catheters (PICC), and femorally inserted central catheters (FICCs)-depending on the clinical conditions of the patients. Regardless of the type of access, the presence of paraplegia or tetraplegia is commonly considered a risk factor for catheter-related thrombosis (CRT).

METHOD

This retrospective study analyzes the rate of CRT and other non-infectious complications associated with central venous access in a cohort of 115 patients with paraplegia or tetraplegia, most of them affected by ALS (n = 109).

RESULTS

In a period of 34 months, from January 2021 to October 2023, we inserted 75 FICCs, 29 CICCs, and 11 PICCs. PICCs were inserted only in patients with preserved motility of the upper limbs. All devices were inserted by trained operators adopting appropriate insertion bundles. We had no immediate or early complication. Though antithrombotic prophylaxis was adopted only in 61.7% of patients, we had no symptomatic CRT. Other non-infectious complications were infrequent (4 out of 115 patients).

CONCLUSION

These results suggest (a) that the presence of paraplegia or tetraplegia is not necessarily associated with an increased risk of CRT, (b) that the adoption of well-designed insertion bundles plays a key role in minimizing non-infectious complications, and (c) that the insertion of FICCs by direct cannulation of the superficial femoral vein at mid-thigh in paraplegic/tetraplegic patients may have the same advantages which have been described in the general population.

Circulating proteomic biomarkers for diagnosing sporadic amyotrophic lateral sclerosis: a cross-sectional study

JOURNAL/nrgr/04.03/01300535-202408000-00039/figure1/v/2023-12-16T180322Z/r/image-tiff Biomarkers are required for the early detection, prognosis prediction, and monitoring of amyotrophic lateral sclerosis, a progressive disease. Proteomics is an unbiased and quantitative method that can be used to detect neurochemical signatures to aid in the identification of candidate biomarkers. In this study, we used a label-free quantitative proteomics approach to screen for substantially differentially regulated proteins in ten patients with sporadic amyotrophic lateral sclerosis compared with five healthy controls. Substantial upregulation of serum proteins related to multiple functional clusters was observed in patients with sporadic amyotrophic lateral sclerosis. Potential biomarkers were selected based on functionality and expression specificity. To validate the proteomics profiles, blood samples from an additional cohort comprising 100 patients with sporadic amyotrophic lateral sclerosis and 100 healthy controls were subjected to enzyme-linked immunosorbent assay. Eight substantially upregulated serum proteins in patients with sporadic amyotrophic lateral sclerosis were selected, of which the cathelicidin-related antimicrobial peptide demonstrated the best discriminative ability between patients with sporadic amyotrophic lateral sclerosis and healthy controls (area under the curve [AUC] = 0.713, P < 0.0001). To further enhance diagnostic accuracy, a multi-protein combined discriminant algorithm was developed incorporating five proteins (hemoglobin beta, cathelicidin-related antimicrobial peptide, talin-1, zyxin, and translationally-controlled tumor protein). The algorithm achieved an AUC of 0.811 and a P-value of < 0.0001, resulting in 79% sensitivity and 71% specificity for the diagnosis of sporadic amyotrophic lateral sclerosis. Subsequently, the ability of candidate biomarkers to discriminate between early-stage amyotrophic lateral sclerosis patients and controls, as well as patients with different disease severities, was examined. A two-protein panel comprising talin-1 and translationally-controlled tumor protein effectively distinguished early-stage amyotrophic lateral sclerosis patients from controls (AUC = 0.766, P < 0.0001). Moreover, the expression of three proteins (FK506 binding protein 1A, cathelicidin-related antimicrobial peptide, and hemoglobin beta-1) was found to increase with disease progression. The proteomic signatures developed in this study may help facilitate early diagnosis and monitor the progression of sporadic amyotrophic lateral sclerosis when used in combination with current clinical-based parameters.

The role of long noncoding RNAs in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease with a poor prognosis leading to death. The diagnosis and treatment of ALS are inherently challenging due to its complex pathomechanism. Long noncoding RNAs (lncRNAs) are transcripts longer than 200 nucleotides involved in different cellular processes, incisively gene expression. In recent years, more studies have been conducted on lncRNA classes and interference in different disease pathologies, showing their promising contribution to diagnosing and treating neurodegenerative diseases. In this review, we discussed the role of lncRNAs like NEAT1 and C9orf72-as in ALS pathogenesis mechanisms caused by mutations in different genes, including TAR DNA-binding protein-43 (TDP-43), fused in sarcoma (FUS), superoxide dismutase type 1 (SOD1). NEAT1 is a well-established lncRNA in ALS pathogenesis; hence, we elaborate on its involvement in forming paraspeckles, stress response, inflammatory response, and apoptosis. Furthermore, antisense lncRNAs (as-lncRNAs), a key group of transcripts from the opposite strand of genes, including ZEB1-AS1 and ATXN2-AS, are discussed as newly identified components in the pathology of ALS. Ultimately, we review the current standing of using lncRNAs as biomarkers and therapeutic agents and the future vision of further studies on lncRNA applications.

Physical therapy for muscle strengthening in individuals with amyotrophic lateral sclerosis: A protocol for a systematic review and meta-analysis

INTRODUCTION

People with Amyotrophic Lateral Sclerosis (ALS) can present initially muscle weakness, which is a debilitating symptom that may be improved by engaging in muscle strengthening activities. Currently, the effects of motor interventions for muscle strengthening in people with ALS are unclear. This review intends to analyze the effects of motor interventions for muscle strengthening in individuals with ALS.

METHODS AND ANALYSIS

Randomized, non-randomized, and quasi-experimental clinical trials assessing individuals with ALS of both sexes, aged 18 years or older, who have received motor interventions for muscle strengthening considering all practices that can lead to increased strength, endurance, power and muscular hypertrophy will be included. No restriction on language, location, or publication date will be applied. MEDLINE, EMBASE, Cochrane Library (CENTRAL), SPORTDiscus, and Physiotherapy Evidence Database (PEDro) databases will be searched. The US National Institutes of Health Ongoing, ClinicalTrials.gov, and the reference lists of included studies will also be searched. Two reviewers will independently screen titles and abstracts and extract data from included studies. The methodological quality of the included studies will be assessed by the PEDro scale and the certainty of the evidence by the GRADE approach. Disagreements will be resolved by a third researcher. Findings will be presented in text and table formats. A meta-analysis will compare the effects of motor interventions for muscle strengthening versus placebo or other interventions.

Allogeneic B cell immunomodulatory therapy in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is an orphan neurodegenerative disease. Immune system dysregulation plays an essential role in ALS onset and progression. Our preclinical studies have shown that the administration of exogenous allogeneic B cells improves outcomes in murine models of skin and brain injury through a process termed pligodraxis, in which B cells adopt an immunoregulatory and neuroprotective phenotype in an injured environment. Here, we investigated the effects of B-cell therapy in the SOD1G93A mouse preclinical model of ALS and in a person living with ALS. Purified splenic mature naïve B cells from haploidentical donor mice were administered intravenously in SOD1G93A mice for a total of 10 weekly doses. For the clinical study in a person with advanced ALS, IgA gammopathy of unclear significance, and B lymphopenia, CD19+ B cells were positively selected from a healthy haploidentical donor and infused intravenously twice, at a 60-day interval. Repeated intravenous B-cell administration was safe and significantly delayed disease onset, extended survival, reduced cellular apoptosis, and decreased astrogliosis in SOD1G93A mice. Repeated B-cell infusion in a person with ALS was safe and did not appear to generate a clinically evident inflammatory response. An improvement of 5 points on the ALSFRS-R scale was observed after the first infusion. Levels of inflammatory markers showed persistent reduction post-infusion. This represents a first demonstration of the efficacy of haploidentical B-cell infusion in the SOD1G93A mouse and the safety and feasibility of using purified haploidentical B lymphocytes as a cell-based therapeutic strategy for a person with ALS.

Genetic link between KIF1A mutations and amyotrophic lateral sclerosis: evidence from whole-exome sequencing

Objectives

Genetics have been shown to have a substantial impact on amyotrophic lateral sclerosis (ALS). The ALS process involves defects in axonal transport and cytoskeletal dynamics. It has been identified that KIF1A, responsible for encoding a kinesin-3 motor protein that carries synaptic vesicles, is considered a genetic predisposing factor for ALS.

Methods

The analysis of whole-exome sequencing data from 1,068 patients was conducted to examine the genetic link between ALS and KIF1A. For patients with KIF1A gene mutations and a family history, we extended the analysis to their families and reanalyzed them using Sanger sequencing for cosegregation analysis.

Results

In our cohort, the KIF1A mutation frequency was 1.31% (14/1,068). Thirteen nonsynonymous variants were detected in 14 ALS patients. Consistent with the connection between KIF1A and ALS, the missense mutation p.A1083T (c.3247G>A) was shown to cosegregate with disease. The mutations related to ALS in our study were primarily located in the cargo-binding region at the C-terminal, as opposed to the mutations of motor domain at the N-terminal of KIF1A which were linked to hereditary peripheral neuropathy and spastic paraplegia. We observed high clinical heterogeneity in ALS patients with missense mutations in the KIF1A gene. KIF5A is a more frequent determinant of ALS in the European population, while KIF1A accounts for a similar proportion of ALS in both the European and Chinese populations.

Conclusion

Our investigation revealed that mutations in the C-terminus of KIF1A could increase the risk of ALS, support the pathogenic role of KIF1A in ALS and expand the phenotypic and genetic spectrum of KIF1A-related ALS.

Comparison of Demographics: National Amyotrophic Lateral Sclerosis Registry and Clinical Trials Data

OBJECTIVE

To characterize the participant demographics in the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) database compared with the web-portal National Amyotrophic Lateral Sclerosis (ALS) Registry (the Registry).

METHODS

Demographics and ALS symptom information were compared between the self-reported registrant data in the Registry web portal (2010-2021) and the latest available PRO-ACT data (updated August 2022), which is a collection of clinical trials data.

RESULTS

Greater percentages of younger (≤ 59 years old) but smaller percentages of older (60 + years old) participants were represented in PRO-ACT compared to Registry. Enrollment for minority race groups was greater in the Registry portal data, but race information was largely missing/unknown in PRO-ACT database. Median age at the time of diagnosis and age at the time of symptom onset were significantly higher for Registry enrollees compared to the participants of PRO-ACT. Symptom onset sites were similarly reported, but duration between self-noted symptom onset and diagnosis was slight, but significantly longer for the Registry enrollees (11 vs. 9 months). Hispanic were as likely as non-Hispanic to participate in research studies, based on the Registry data.

CONCLUSION

There was a notable difference in the age distribution and minority representation of enrollees between the PRO-ACT and Registry study populations. Age distribution in the PRO-ACT database skewed to a younger and less diverse cohort. Despite the clinical heterogeneity and complex disease mechanism of ALS, identifying the underrepresented demographic niche in the PRO-ACT and Registry study populations can help improve patient participation and criteria for patient selection to enhance generalizability.

The MuSK agonist antibody protects the neuromuscular junction and extends the lifespan in C9orf72-ALS mice

The disassembly of the neuromuscular junction (NMJ) is an early event in amyotrophic lateral sclerosis (ALS), ultimately leading to motor dysfunction and lethal respiratory paralysis. The hexanucleotide GGGGCC repeat expansion in the C9orf72 gene is the most common genetic mutation, and the dipeptide repeat (DPR) proteins have been shown to cause neurodegeneration. While no drugs can treat ALS patients efficiently, new treatment strategies are urgently needed. Here, we report that a MuSK agonist antibody alleviates poly-PR-induced NMJ deficits in C9orf72-ALS mice. The HB9-PRF/F mice, which express poly-PR proteins in motor neurons, exhibited impaired motor behavior and NMJ deficits. Mechanistically, poly-PR proteins interacted with Agrin to disrupt the interaction between Agrin and Lrp4, leading to attenuated activation of MuSK. Treatment with a MuSK agonist antibody rescued NMJ deficits, and extended the lifespan of C9orf72-ALS mice. Moreover, impaired NMJ transmission was observed in C9orf72-ALS patients. These findings identify the mechanism by which poly-PR proteins attenuate MuSK activation and NMJ transmission, highlighting the potential of promoting MuSK activation with an agonist antibody as a therapeutic strategy to protect NMJ function and prolong the lifespan of ALS patients.

Outcomes after intervention for enteral nutrition in patients with amyotrophic lateral sclerosis in multidisciplinary clinics

INTRODUCTION/AIMS

Patients with amyotrophic lateral sclerosis (ALS) are susceptible to malnutrition, with appropriate management of nutritional interventions an active area of investigation. We sought to determine the impact of gastrostomy tube placement in ALS patients, exploring the correlation between forced vital capacity (FVC), malnutrition, and perioperative complications.

METHODS

A retrospective review was performed of clinically diagnosed ALS patients treated at two multidisciplinary clinics (University of Kansas, University of Nebraska) from January 2009 to September 2020 who were referred for gastrostomy. Data collected included demographics, disease characteristics, and key gastrostomy related dates/outcomes.

RESULTS

Two hundred thirty-nine patients were included with a median age of 65 years and median of 589 days from symptom onset to gastrostomy (interquartile range, 404-943). The population was predominantly Non-Hispanic White with bulbar-onset ALS. 30-day mortality was 4% and 30-day morbidity was 13%. Weight loss, body mass index, and predicted FVC at placement showed no increased 30-day morbidity or mortality association. Bulbar-onset ALS patients exhibited higher overall mortality postplacement than limb onset (odds ratio: 1.85, 95% confidence interval: 1.03-3.33). There was a 5% incidence of symptoms suggestive of refeeding syndrome.

DISCUSSION

Rates of major/minor complications and 30-day mortality related to gastrostomy placement in our population were similar compared with prior studies in ALS. The lack of difference in outcomes based on FVC at procedure may suggest this is not predictive of outcome, or perhaps, high-quality perioperative respiratory management. Alternative reasons may account for the increased morbidity and mortality of gastrostomy placement in the ALS population.

Anesthetic Management of a Neurosurgical Patient With Amyotrophic Lateral Sclerosis: A Case Report

Amyotrophic lateral sclerosis (ALS) is a progressive form of neurological disorder that affects both the upper and lower motor neurons. Anesthesia management in these patients is always challenging as they can develop respiratory complications because of pre-existing muscle involvement. We report a middle-aged male with ALS posted for chronic subdural hematoma evacuation (CSDH) surgery. Surgery was done under scalp block with monitored anesthesia care. The choice of anesthesia in these patients should be one that interferes the least with the disease pattern while still providing optimal conditions for surgery.

Comparison of in-person vs. remote administration of cognitive screening tools for people with ALS

OBJECTIVE

This study investigated whether cognitive screening tools used for people with amyotrophic lateral sclerosis (pwALS) are affected by the screen being administered face-to-face or remotely online. It also investigated whether demographic variables predicted total cognitive screen scores.

METHODS

The cognitive component of the Edinburgh Cognitive and Behavioural ALS Screen (ECASc), the cognitive component of the ALS Cognitive Behavioural Screen (ALS-CBSc), and the Mini Addenbrooke's Cognitive Examination (Mini-ACE) were administered to 41 pwALS and 41 controls face-to-face. Versions of the cognitive screens designed to be administered remotely were administered to 57 pwALS and 44 controls via videoconferencing methods. Backwards stepwise linear regressions were conducted to assess whether total scores on the ECASc, ALS-CBSc, and Mini-ACE scores were predicted by administration mode (face-to-face or remote) or demographic variables.

RESULTS

Mode of administration significantly affected scores on the ECASc and ALS-CBSc; remote administration was associated with better total scores. Administration mode did not significantly affect Mini-ACE scores. All cognitive screens were significantly affected by IQ scores; higher IQ scores predicted better screening tool scores. Only ECASc scores were significantly affected by age, with older age predicting poorer scores. Being female was associated with better Mini-ACE scores; sex did not predict ECASc and ALS-CBSc scores.

CONCLUSIONS

Our results suggest that videoconferencing versions of the ECASc and ALS-CBSc may function differently to the original, face-to-face versions. There are advantages to using remote versions of cognitive screening tools but clinicians and researchers who use them should consider that they may not yield equivalent scores.

Single-nucleus sequencing reveals enriched expression of genetic risk factors in extratelencephalic neurons sensitive to degeneration in ALS

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by a progressive loss of motor function linked to degenerating extratelencephalic neurons/Betz cells (ETNs). The reasons why these neurons are selectively affected remain unclear. Here, to understand the unique molecular properties that may sensitize ETNs to ALS, we performed RNA sequencing of 79,169 single nuclei from cortices of patients and controls. In both patients and unaffected individuals, we found significantly higher expression of ALS risk genes in THY1+ ETNs, regardless of diagnosis. In patients, this was accompanied by the induction of genes involved in protein homeostasis and stress responses that were significantly induced in a wide collection of ETNs. Examination of oligodendroglial and microglial nuclei revealed patient-specific downregulation of myelinating genes in oligodendrocytes and upregulation of an endolysosomal reactive state in microglia. Our findings suggest that selective vulnerability of extratelencephalic neurons is partly connected to their intrinsic molecular properties sensitizing them to genetics and mechanisms of degeneration.

Causal relationship and shared genes between air pollutants and amyotrophic lateral sclerosis: A large-scale genetic analysis

OBJECTIVE

Air pollutants have been reported to have a potential relationship with amyotrophic lateral sclerosis (ALS). The causality and underlying mechanism remained unknown despite several existing observational studies. We aimed to investigate the potential causality between air pollutants (PM2.5, NOX, and NO2) and the risk of ALS and elucidate the underlying mechanisms associated with this relationship.

METHODS

The data utilized in our study were obtained from publicly available genome-wide association study data sets, in which single nucleotide polymorphisms (SNPs) were employed as the instrumental variantswith three principles. Two-sample Mendelian randomization and transcriptome-wide association (TWAS) analyses were conducted to evaluate the effects of air pollutants on ALS and identify genes associated with both pollutants and ALS, followed by regulatory network prediction.

RESULTS

We observed that exposure to a high level of PM2.5 (OR: 2.40 [95% CI: 1.26-4.57], p = 7.46E-3) and NOx (OR: 2.35 [95% CI: 1.32-4.17], p = 3.65E-3) genetically increased the incidence of ALS in MR analysis, while the effects of NO2 showed a similar trend but without sufficient significance. In the TWAS analysis, TMEM175 and USP35 turned out to be the genes shared between PM2.5 and ALS in the same direction.

CONCLUSION

Higher exposure to PM2.5 and NOX might causally increase the risk of ALS. Avoiding exposure to air pollutants and air cleaning might be necessary for ALS prevention.

Threshold tracking transcranial magnetic stimulation and neurofilament light chain as diagnostic aids in ALS

OBJECTIVE

There is a need for sensitive biomarkers in amyotrophic lateral sclerosis (ALS), to enable earlier diagnosis and to help assess potential treatments. The main objective of this study was to compare two potential biomarkers, threshold-tracking short-interval cortical inhibition (T-SICI), which has shown promise as a diagnostic aid, and neurofilament light chains (NfL).

METHODS

Ninety-seven patients with ALS (mean age 67.1 ± 11.5 years) and 53 ALS mimics (aged 62.4 ± 12.9) were included. Mean disease duration was 14 months ±14.1. Patients were evaluated with revised ALS functional rating score (ALSFRS-R), Penn upper motor neuron score (UMNS), muscle strength using the Medical Research Council (MRC) score and examined with T-SICI, quantitative electromyography (EMG), and NfL measured in spinal fluid.

RESULTS

NfL increased with increasing UMNS (rho = 0.45, p = 8.2 × 10-6) whereas T-SICI at 2.5 ms paradoxically increased toward normal values (rho = 0.53, p = 1.9 × 10-7). However, these two measures were uncorrelated. Discrimination between ALS patients and mimics was best for NfL (area under ROC curve 0.842, sensitivity 84.9%, specificity 83.5%), compared with T-SICI (0.675, 39.6%, 91.8%). For the patients with no UMN signs, NfL also discriminated best (0.884, 89.3%, 82.6%), compared with T-SICI (0.811, 71.4%, 82.6%). However, when combining NfL and T-SICI, higher AUCs of 0.854 and 0.922 and specificities of 93.8 and 100 were found when considering all patients and patients with no UMN signs, respectively.

INTERPRETATION

Both T-SICI and NfL correlated with UMN involvement and combined, they provided a strong discrimination between ALS patients and ALS mimics.

Diagnostic value of neurofilaments in differentiating motor neuron disease from multifocal motor neuropathy

OBJECTIVE

To evaluate the performance of serum neurofilament light chain (NfL) and cerebrospinal fluid (CSF) phosphorylated neurofilament heavy chain (pNfH) as diagnostic biomarkers for the differentiation between motor neuron disease (MND) and multifocal motor neuropathy (MMN).

METHODS

This retrospective, monocentric study included 16 patients with MMN and 34 incident patients with MND. A subgroup of lower motor neuron (MN) dominant MND patients (n = 24) was analyzed separately. Serum NfL was measured using Ella automated immunoassay, and CSF pNfH was measured using enzyme-linked immunosorbent assay. Area under the curve (AUC), optimal cutoff values (Youden's index), and correlations with demographic characteristics were calculated.

RESULTS

Neurofilament concentrations were significantly higher in MND compared to MMN (p < 0.001), and serum NfL and CSF pNfH correlated strongly with each other (Spearman's rho 0.68, p < 0.001). Serum NfL (AUC 0.946, sensitivity and specificity 94%) and CSF pNfH (AUC 0.937, sensitivity 90.0%, specificity 100%) performed excellent in differentiating MND from MMN. Optimal cutoff values were ≥ 44.15 pg/mL (serum NfL) and ≥ 715.5 pg/mL (CSF pNfH), respectively. Similar results were found when restricting the MND cohort to lower MN dominant patients. Only one MMN patient had serum NfL above the cutoff. Two MND patients presented with neurofilament concentrations below the cutoffs, both featuring a slowly progressive disease.

CONCLUSION

Neurofilaments are valuable supportive biomarkers for the differentiation between MND and MMN. Serum NfL and CSF pNfH perform similarly well and elevated neurofilaments in case of diagnostic uncertainty underpin MND diagnosis.