Time-trend evolution and determinants of sex ratio in Amyotrophic Lateral Sclerosis: a dose-response meta-analysis

Update on recent advances in amyotrophic lateral sclerosis

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

Clinical and genetic characteristics of 1672 cases of amyotrophic lateral sclerosis in China: a single-center retrospective study

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. In recent years, continuous discoveries of new ALS-causing genes have enhanced the understanding of the genotype-phenotype relationship in ALS, aiding in disease progression prediction and providing a more comprehensive basis for genetic diagnosis.

METHODS

A total of 1672 ALS patients who visited the Neurology Department of Peking Union Medical College Hospital between January 2014 and December 2022 and met the revised El Escorial diagnostic criteria were included. Clinical data were collected, whole exome sequencing and dynamic mutation screening of the C9ORF72 gene were performed, and the clinical phenotypes and genotypes of the patients were analyzed.

RESULTS

The average age of onset for the 1672 ALS patients was 52.6 ± 11.2 years (range 17-85 years), with a median disease duration of 14 months at the time of visit (interquartile range 9-24 months, range 2-204 months). The male to female ratio was 833:839. The patients included 297 (17.8%) with bulbar onset, 198 (11.8%) with flail arm/leg syndrome, 89 (5.3%) with familial ALS, and 52 (3.1%) with concomitant frontotemporal dementia (FTD). Pathogenic variants associated with ALS were detected in 175 patients (10.5% of the cohort), with the most common mutations being SOD1, FUS, and ANXA11. Among patients with familial ALS, 56.2% (50/89) had genetic mutations, compared to 7.9% (125/1583) in sporadic ALS cases. From the perspective of phenotype-genotype correlation, (1) In ALS-FTD patients, the most common genetic mutations were ANXA11 and C9ORF72 repeat expansions. Patients with flail arm/leg syndrome more frequently carried mutations in SOD1, ANXA11, and hnRNPA1; (2) Despite genetic heterogeneity, it was observed that mutations in FUS and NEK1 were more common in males, and patients with FUS mutations had a younger age of onset; mutations in SOD1 and SQSTM1 were more likely to present with lower limb onset.

CONCLUSION

This study provides comprehensive data on the genetic characteristics of ALS patients in China through large-scale clinical data and genetic analysis of 1672 cases. Differences in age of onset, onset site, and clinical phenotype among ALS patients with different genotypes can help clinicians better predict disease progression and provide a basis for precise diagnosis and individualized treatment.

Chitinases as a potential diagnostic and prognostic biomarker for amyotrophic lateral sclerosis: a systematic review and meta-analysis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the degeneration of motor neurons, and there is currently a lack of reliable diagnostic biomarkers. This meta-analysis aimed to evaluate CHIT1, CHI3L1, and CHI3L2 levels in the cerebrospinal fluid (CSF) or blood and their diagnostic potential in ALS patients. A systematic, comprehensive search was performed of peer-reviewed English-language articles published before April 1, 2023, in PubMed, Scopus, Embase, Cochrane Library, and Web of Science. After a thorough screening, 13 primary articles were included, and their chitinases-related data were extracted for systematic review and meta-analysis. In ALS patients, the CSF CHIT1 levels were significantly elevated compared to controls with healthy control (HC) (SMD, 1.92; 95% CI, 0.78 - 3.06; P < 0.001). CHIT1 levels were elevated in the CSF of ALS patients compared to other neurodegenerative diseases (ONDS) control (SMD, 0.74; 95% CI, 0.22 - 1.27; P < 0.001) and exhibited an even more substantial increase when compared to ALS-mimicking diseases (AMDS) (SMD, 1.15; 95% CI, 0.35 - 1.94, P < 0.001). Similarly, the CSF CHI3L1 levels were significantly higher in ALS patients compared to HC (SMD, 3.16; 95% CI, 1.26 - 5.06, P < 0.001). CHI3L1 levels were elevated in the CSF of ALS patients compared to ONDS (SMD, 0.75; 95% CI, 0.32 - 1.19; P = 0.017) and exhibited a more pronounced increase when compared to AMDS (SMD, 1.92; 95% CI, 0.41 - 3.42; P < 0.001). The levels of CSF chitinases in the ALS patients showed a significant increase, supporting the role of CSF chitinases as diagnostic biomarkers for ALS.

Drug Screening and Validation Targeting TDP-43 Proteinopathy for Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) stands as a rare, yet severely debilitating disorder marked by the deterioration of motor neurons (MNs) within the brain and spinal cord, which is accompanied by degenerated corticobulbar/corticospinal tracts and denervation in skeletal muscles. Despite ongoing research efforts, ALS remains incurable, attributed to its intricate pathogenic mechanisms. A notable feature in the pathology of ALS is the prevalence of TAR DNA-binding protein 43 (TDP-43) proteinopathy, detected in approximately 97% of ALS cases, underscoring its significance in the disease's progression. As a result, strategies targeting the aberrant TDP-43 protein have garnered attention as a potential avenue for ALS therapy. This review delves into the existing drug screening systems aimed at TDP-43 proteinopathy and the models employed for drug efficacy validation. It also explores the hurdles encountered in the quest to develop potent medications against TDP-43 proteinopathy, offering insights into the intricacies of drug discovery and development for ALS. Through this comprehensive analysis, the review sheds light on the critical aspects of identifying and advancing therapeutic solutions for ALS.

NRF2 signaling cascade in amyotrophic lateral sclerosis: bridging the gap between promise and reality

Amyotrophic lateral sclerosis is a very disabling disease due to the degeneration of motor neurons. Symptoms include muscle weakness and atrophy, spasticity, and progressive paralysis. Currently, there is no treatment to reverse damage to motor neurons and cure amyotrophic lateral sclerosis. The only two treatments actually approved, riluzole and edaravone, have shown mitigated beneficial effects. The difficulty to find a cure lies in the complexity and multifaceted pattern of amyotrophic lateral sclerosis pathogenesis. Among mechanisms, abnormal RNA metabolism, nucleocytoplasmic transport defects, accumulation of unfolded protein, and mitochondrial dysfunction would in fine induce oxidative damage and vice versa. A potent therapeutic strategy will be to find molecules that break this vicious circle. Sharpening the nuclear factor erythroid-2 related factor 2 signaling may fulfill this objective since nuclear factor erythroid-2 related factor 2 has a multitarget profile controlling antioxidant defense, mitochondrial functioning, and inflammation. We here discuss the interest of developing nuclear factor erythroid-2 related factor 2-based therapy in regard to the pathophysiological mechanisms and we provide a general overview of the attempted clinical assays in amyotrophic lateral sclerosis.

Estimated Familial Amyotrophic Lateral Sclerosis Proportion: A Literature Review and Meta-analysis

Background and Objectives

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disorder. Familial (fALS) cases are usually reported to constitute 5%-10% of all ALS cases; however, no recent literature review or meta-analysis of this proportion (referred to throughout as "proportion fALS") has been conducted. Our objective was to estimate the proportion fALS by geographic region and to assess the effect of study characteristics on the estimates.

Methods

A comprehensive literature review was performed to identify all original studies reporting the number of fALS cases in an ALS cohort. The results were stratified by geographic region, study design (case series or population-based), and decade of study publication. Subgroup analyses were conducted according to family history criteria used to define fALS. We report pooled estimates of the proportion fALS from random-effects meta-analyses when >2 studies are available and I2 is < 90%; weighted averages and ranges are otherwise presented.

Results

The overall pooled proportion fALS based on a total 165 studies was 8% (0%, 71%). The proportion fALS was 9% (0%, 71%) among 107 case series and 5% (4%, 6%) among 58 population-based studies. Among population-based studies, proportion fALS by geographic region was 6% (5%, 7%; N = 37) for Europe, 5% (3%, 7%; N = 5) for Latin America, and 5% (4%, 7%; N = 12) for North America. Criteria used to define fALS were reported by 21 population-based studies (36%), and proportion fALS was 5% (4%, 5%; N = 9) for first-degree relative, 7% (4%, 11%; N = 4) for first or second-degree relative, and 11% (N = 1) for more distant ALS family history. Population-based studies published in the 2000s or earlier generated a lower pooled proportion fALS than studies published in the 2010s or later.

Discussion

The results suggest that variability in the reported proportion fALS in the literature may be, in part, due to the differences in geography, study design, fALS definition, and decade of case ascertainment. Few studies outside of European ancestral populations were available. The proportion fALS was marginally higher among case series compared with population-based studies, likely because of referral bias. Criteria used to define fALS were largely unreported. Consensus criteria for fALS and additional population-based studies in non-European ancestral populations are needed.

What can epidemiological studies teach on the pathophysiology of adult-onset isolated dystonia?

Several demographic and environmental factors may play an important role in determining the risk of developing adult-onset isolated dystonia (AOID) and/or modifying its course. However, epidemiologic studies have provided to date only partial insight on the disease mechanisms that are actively influenced by these factors. The age-related increase in female predominance in both patients diagnosed with AOID and subjects carrying its putative mediational phenotype suggests sexual dimorphism that has been demonstrated for mechanisms related to blepharospasm and cervical dystonia. The opposite relationship that spread and spontaneous remission of AOID have with age suggests age-related decline of compensatory mechanisms that protect from the progression of AOID. Epidemiological studies focusing on environmental risk factors yielded associations only with specific forms of AOID, even for those factors that are not likely to predispose exclusively to specific focal forms (for example, only writing dystonia was found associated with head trauma, and only blepharospasm with coffee intake). Other factors show biological plausibility of their mechanistic role for specific forms, e.g., dry eye syndrome or sunlight exposure for blepharospasm, scoliosis for cervical dystonia, repetitive writing for writing dystonia. Overall, the relationship between environment and AOID remains complex and incompletely defined. Both hypothesis-driven preclinical studies and well-designed cross-sectional or prospective clinical studies are still necessary to decipher this intricate relationship.

Epidemiology of amyotrophic lateral sclerosis in the north east Tuscany in the 2018–2021 period

Background

The incidence of Amyotrophic Lateral Sclerosis (ALS) varies among different geographical areas and seems to increase over time. This study aimed to examine the epidemiologic data of ALS in the north-east Tuscany and compare the results with those of similar surveys.

Methods

Data from ALS cases diagnosed in Florence and Prato Hospitals were prospectively collected from 1st June 2018 to 31st May 2021.

Results

The age- and sex-adjusted incidence rate of ALS in cases per 100,000 population was 2.71 (M/F ratio: 1.21), significantly higher as compared to that reported in the 1967-1976 decade in the same geographical area (0.714). The age- and sex-adjusted incidence rate among resident strangers was similar to that of the general population (2.69). A slightly higher incidence rate (4.36) was observed in the north-east area of Florence province, which includes the Mugello valley. The mean prevalence was of 7.17/100,00. The mean age at diagnosis was 69.7 years, with a peak between 70 and 79 years among men and a smoother age curve among women.

Conclusions

ALS epidemiological features in north-east Tuscany are in line with other Italian and European Centers. The dramatic increase of the local disease burden over the last decades probably reflects better ascertainment methods and health system.

Sex and gender differences in Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis: a narrative review

Neurodegenerative diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), exhibit high phenotypic variability and they are very common in the general population. These diseases are associated with poor prognosis and a significant burden on patients and their caregivers. Although increasing evidence suggests that biological sex is an important factor for the development and phenotypical expression of some NDs, the role of sex and gender in the diagnosis and prognosis of NDs has been poorly explored. Current knowledge relating to sex- and gender-related differences in the epidemiology, clinical features, biomarkers, and treatment of AD, PD, and ALS will be summarized in this narrative review. The cumulative evidence hitherto collected suggests that sex and gender are factors to be considered in explaining the heterogeneity of these NDs. Clarifying the role of sex and gender in AD, PD, and ALS is a key topic in precision medicine, which will facilitate sex-specific prevention and treatment strategies to be implemented in the near future.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a fatal CNS neurodegenerative disease. Despite intensive research, current management of amyotrophic lateral sclerosis remains suboptimal from diagnosis to prognosis. Recognition of the phenotypic heterogeneity of amyotrophic lateral sclerosis, global CNS dysfunction, genetic architecture, and development of novel diagnostic criteria is clarifying the spectrum of clinical presentation and facilitating diagnosis. Insights into the pathophysiology of amyotrophic lateral sclerosis, identification of disease biomarkers and modifiable risks, along with new predictive models, scales, and scoring systems, and a clinical trial pipeline of mechanism-based therapies, are changing the prognostic landscape. Although most recent advances have yet to translate into patient benefit, the idea of amyotrophic lateral sclerosis as a complex syndrome is already having tangible effects in the clinic. This Seminar will outline these insights and discuss the status of the management of amyotrophic lateral sclerosis for the general neurologist, along with future prospects that could improve care and outcomes for patients with amyotrophic lateral sclerosis.

Epidemiological time-trend of amyotrophic lateral sclerosis (ALS) over two decades: The French population-based register of ALS in Limousin (FRALim register)

INTRODUCTION

Population-based registers are key to understanding disease patterns. Taking advantage of the long-standing operation of the French register of amyotrophic lateral sclerosis (ALS) in Limousin (FRALim register), we sought to determine the time trends in incidence, clinical features and survival of ALS patients from 2000 to 2020.

METHODS

FRALim register included incident cases through multiple sources of ascertainment. A capture-recapture method was used to assess the exhaustiveness of case ascertainment. Crude and standardized incidences were calculated per 100,000 person-years of follow-up (PYFU). Time-period was divided (period 2000 to 2010 and period 2011 to 2020) to compare incidence rates and clinical features. Survival was analyzed using Kaplan-Meier method. Cox proportional hazards model was performed to calculate hazards for the time periods.

RESULTS

Overall, 501 incident cases were identified during 21 years. The overall crude incidence was 3.26 (95% CI 2.97 to 3.55) per 100 000 PYFU. The exhaustiveness of the register was estimated at 98.8% (95% CI 97.4-99.6%) by capture-recapture analysis. Several fluctuations were observed without a consistent trend over the last two decades. The crude and standardized incidences were higher in males than females. The peak of incidence was observed in the 75-79 years age band. Almost one-third of the cases exhibited a bulbar onset. There were significant differences in clinical features between time periods. Four hundred and ninety-one cases were included in the survival analysis. The median survival time from diagnosis was 16.0 months (95% CI 14.3 to 17.7 months). Patients in the last decade experienced a lower risk of dying but the difference did not reach statistical significance (adjusted HR: 0.89 (95% CI 0.73 to 1.08, P=0.229).

CONCLUSION

We provided reliable epidemiological data over two decades. We showed that incidence has been relatively stable, while clinical variability was observed. A slight improvement in survival time was found in the last decade but it was not statistically significant. Further quality register data are needed to improve our understanding of ALS epidemiological trends.

Amyotrophic lateral sclerosis mortality rates in Latin America and the Caribbean: a meta-analysis

Background: Recent studies have described a low occurrence of Amyotrophic Lateral Sclerosis (ALS) in Latin America. Significant differences in ALS risk have been reported among ethnic populations in the region. We conducted a meta-analysis using population-based data to describe ALS mortality rates in Latin America. We explored sources of heterogeneity among key covariates.Methods: National mortality registries from Latin American countries were searched to identify ALS deaths according to the International Classification of Diseases (ICD-9: code 335.2 and ICD-10: code G12.2). Crude and standardized mortality rates were calculated. A random-effect meta-analysis was conducted to estimate pooled mortality rates. Subgroup analysis was performed as a means of investigating heterogeneity.Results: Overall, 28,548 ALS deaths and 819 million person-years of follow-up (PYFU) from ten Latin American countries were considered. Standardized mortality varied among countries. The highest mortality rates were observed in Uruguay and Costa Rica at 1.3 and 1.2 per 100,000 PYFU, respectively. The pooled crude mortality rate was 0.38 (95%CI: 0.28-0.53) and the pooled standardized mortality was 0.62 (95%CI: 0.49-0.77) per 100,000 PYFU. Heterogeneity was high (I2: 99.9%, Cochran's Q p < 0.001). Subgroup analysis showed a higher mortality rate among countries with a higher proportion of Caucasian populations and higher income levels.Conclusion: There is a lower ALS occurrence in Latin America compared to Europe and North America. This meta-analysis supports the hypothesis of a higher ALS risk among the Caucasian population. Further studies are needed to investigate the role of ancestral origins in ALS, taking socioeconomic status into consideration.

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.