Hypermetabolism associated with worse prognosis of amyotrophic lateral sclerosis

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.

Variation in Resting Metabolic Rate Affects Identification of Metabolic Change in Geographically Distinct Cohorts of Patients With ALS

BACKGROUND AND OBJECTIVES

Altered metabolism is observed in amyotrophic lateral sclerosis (ALS). However, without a standardized methodology to define metabolic changes, our understanding of factors contributing to and the clinical significance of altered metabolism in ALS is limited.

METHODS

We aimed to determine how geographic variation in metabolic rates influences estimates and accuracy of predicted resting energy expenditure (REE) in patients with ALS and controls, while validating the effectiveness of cohort-specific approaches in predicting altered metabolic rate in ALS. Participants from 3 geographically distinct sites across Australia, China, and the Netherlands underwent REE assessments, and we considered 22 unique equations for estimating REE. Analyses evaluated equation performance and the influence of demographics on metabolic status. Comparisons were made using standardized and local reference values to identify metabolic alterations.

RESULTS

606 participants were included from Australia (patients with ALS: 140, controls: 154), the Netherlands (patients with ALS: 79, controls: 37) and China (patients with ALS: 67, controls: 129). Measured REE was variable across geographic cohorts, with fat-free mass contributing to this variation across all patients (p = 0.002 to p < 0.001). Of the 22 predication equations assessed, the Sabounchi Structure 4 (S4) equation performed relatively well across all control cohorts. Use of prediction thresholds generated using data from Australian controls generally increased the prevalence of hypermetabolism in Chinese (55%, [43%-67%]) and Dutch (44%, [33%-55%]) cases when compared with Australian cases (30%, [22%-38%]). Adjustment of prediction thresholds to consider geographically distinct characteristics from matched control cohorts resulted in a decrease in the proportion of hypermetabolic cases in Chinese and Dutch cohorts (25%-31% vs 55% and 20%-34% vs 43%-44%, respectively), and increased prevalence of hypometabolism in Dutch cases with ALS (1% to 8%-10%).

DISCUSSION

The identification of hypermetabolism in ALS is influenced by the formulae and demographic-specific prediction thresholds used for defining alterations in metabolic rate. A consensus approach is needed for identification of metabolic changes in ALS and will facilitate improved understanding of the cause and clinical significance of this in ALS.

Unsupervised machine learning identifies distinct ALS molecular subtypes in post-mortem motor cortex and blood expression data

Amyotrophic lateral sclerosis (ALS) displays considerable clinical and genetic heterogeneity. Machine learning approaches have previously been utilised for patient stratification in ALS as they can disentangle complex disease landscapes. However, lack of independent validation in different populations and tissue samples have greatly limited their use in clinical and research settings. We overcame these issues by performing hierarchical clustering on the 5000 most variably expressed autosomal genes from motor cortex expression data of people with sporadic ALS from the KCL BrainBank (N = 112). Three molecular phenotypes linked to ALS pathogenesis were identified: synaptic and neuropeptide signalling, oxidative stress and apoptosis, and neuroinflammation. Cluster validation was achieved by applying linear discriminant analysis models to cases from TargetALS US motor cortex (N = 93), as well as Italian (N = 15) and Dutch (N = 397) blood expression datasets, for which there was a high assignment probability (80-90%) for each molecular subtype. The ALS and motor cortex specificity of the expression signatures were tested by mapping KCL BrainBank controls (N = 59), and occipital cortex (N = 45) and cerebellum (N = 123) samples from TargetALS to each cluster, before constructing case-control and motor cortex-region logistic regression classifiers. We found that the signatures were not only able to distinguish people with ALS from controls (AUC 0.88 ± 0.10), but also reflect the motor cortex-based disease process, as there was perfect discrimination between motor cortex and the other brain regions. Cell types known to be involved in the biological processes of each molecular phenotype were found in higher proportions, reinforcing their biological interpretation. Phenotype analysis revealed distinct cluster-related outcomes in both motor cortex datasets, relating to disease onset and progression-related measures. Our results support the hypothesis that different mechanisms underpin ALS pathogenesis in subgroups of patients and demonstrate potential for the development of personalised treatment approaches. Our method is available for the scientific and clinical community at https://alsgeclustering.er.kcl.ac.uk .

The complexity of multidisciplinary respiratory care in amyotrophic lateral sclerosis

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

Educational aims

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

Nutritional and metabolic factors in amyotrophic lateral sclerosis

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

Risk factors associated with amyotrophic lateral sclerosis based on the observational study: a systematic review and meta-analysis

Objective

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder affecting the upper and lower motor neurons. Though the pathogenesis of ALS is still unclear, exploring the associations between risk factors and ALS can provide reliable evidence to find the pathogenesis. This meta-analysis aims to synthesize all related risk factors of ALS to understand this disease comprehensively.

Methods

We searched the following databases: PubMed, EMBASE, Cochrane library, Web of Science, and Scopus. Moreover, observational studies, including cohort studies, and case-control studies, were included in this meta-analysis.

Results

A total of 36 eligible observational studies were included, and 10 of them were cohort studies and the rest were case-control studies. We found six factors exacerbated the progression of disease: head trauma (OR = 1.26, 95% CI = 1.13, 1.40), physical activity (OR = 1.06, 95% CI = 1.04, 1.09), electric shock (OR = 2.72, 95% CI = 1.62, 4.56), military service (OR = 1.34, 95% CI = 1.11, 1.61), pesticides (OR = 1.96, 95% CI = 1.7, 2.26), and lead exposure (OR = 2.31, 95% CI = 1.44, 3.71). Of note, type 2 diabetes mellitus was a protective factor for ALS. However, cerebrovascular disease (OR = 0.99, 95% CI = 0.75, 1.29), agriculture (OR = 1.22, 95% CI = 0.74, 1.99), industry (OR = 1.24, 95% CI = 0.81, 1.91), service (OR = 0.47, 95% CI = 0.19, 1.17), smoking (OR = 1.25, 95% CI = 0.5, 3.09), chemicals (OR = 2.45, 95% CI = 0.89, 6.77), and heavy metal (OR = 1.5, 95% CI = 0.47, 4.84) were not risk factors for ALS based on meta-analyses.

Conclusions

Head trauma, physical activity, electric shock, military service, pesticides, and lead were risk factors for ALS onset and progression. But DM was a protective factor. This finding provides a better understanding of ALS risk factors with strong evidence for clinicians to rationalize clinical intervention strategies.

INPLSY registration number

https://inplasy.com/inplasy-2022-9-0118/, INPLASY202290118.

Biofluid Biomarkers in the Prognosis of Amyotrophic Lateral Sclerosis: Recent Developments and Therapeutic Applications

Amyotrophic lateral sclerosis is a neurodegenerative disease characterized by the degeneration of motor neurons for which effective therapies are lacking. One of the most explored areas of research in ALS is the discovery and validation of biomarkers that can be applied to clinical practice and incorporated into the development of innovative therapies. The study of biomarkers requires an adequate theoretical and operational framework, highlighting the "fit-for-purpose" concept and distinguishing different types of biomarkers based on common terminology. In this review, we aim to discuss the current status of fluid-based prognostic and predictive biomarkers in ALS, with particular emphasis on those that are the most promising ones for clinical trial design and routine clinical practice. Neurofilaments in cerebrospinal fluid and blood are the main prognostic and pharmacodynamic biomarkers. Furthermore, several candidates exist covering various pathological aspects of the disease, such as immune, metabolic and muscle damage markers. Urine has been studied less often and should be explored for its possible advantages. New advances in the knowledge of cryptic exons introduce the possibility of discovering new biomarkers. Collaborative efforts, prospective studies and standardized procedures are needed to validate candidate biomarkers. A combined biomarkers panel can provide a more detailed disease status.

Malnutrition assessment by Global Leadership Initiative on Malnutrition criteria in patients with amyotrophic lateral sclerosis

Malnutrition can play an important prognostic role in terms of survival in patients with amyotrophic lateral sclerosis (ALS). In this clinical context, applying criteria defining malnutrition requires particular attention, especially in the initial stage of the disease. This article discusses the application of the most recent criteria used for the definition of malnutrition when applied to patients with ALS. Currently, the Global Leadership Initiative on Malnutrition (GLIM) criteria, which have received a worldwide consensus, are based on parameters such as unintentional weight loss, low body mass index (BMI), and reduced muscle mass (phenotypic criteria) in combination with reduced food intake and assimilation or inflammation and disease (etiologic criteria). However, as discussed in this review, the initial unintentional weight loss and the consequent BMI reduction could be attributed, at least in part, to muscle atrophy, which also alters the reliability of muscle mass assessment. Moreover, the condition of hypermetabolism, which is observed in up to 50% of these patients, may complicate the calculation of total energy requirements. Finally, it remains to be established if the presence of neuroinflammation can be considered a type of inflammatory process able to induce malnutrition in these patients. In conclusion, the monitoring of BMI, associated with body composition evaluation by bioimpedance measurement or specific formulas, could be a practicable approach to the diagnosis of malnutrition in patients with ALS. In addition, attention should be given to dietary intake (e.g., in patients with dysphagia) and excessive involuntary weight loss. On the other hand, as suggested by GLIM criteria, a single assessment of BMI resulting in <20 kg/m² or <22 kg/m² in patients aged <70 y and ≥70 y, respectively, should always be considered a sign of malnutrition.

Clinical relevance of macroglossia to disease progression in ventilation dependent patients with advanced ALS

BACKGROUND

Macroglossia is one of the clinical signs that emerges in patients with amyotrophic lateral sclerosis (ALS) who are undergoing invasive ventilation.

OBJECTIVE

We aimed to investigate the relationship between the progression of macroglossia and the clinical characteristics during the advanced stages of ALS.

METHODS

Forty-one patients with ALS using invasive ventilation with tracheostomy were prospectively followed over a 3-year period. We evaluated the prevalence of macroglossia, motor disabilities including oral function, communication ability (communication stage I to V) as a marker of disease progression, and nutritional factors. We analyzed the potential factors affecting the progression of macroglossia using a multivariate logistic analysis.

RESULTS

The number of patients with macroglossia was increased during the follow-up (from 24.4 to 53.7%), while the communication stage progressed from 2.6 in average (SD 1.7) to 3.5 (1.4). During the study, body weight increased, while energy intake decreased, suggesting progressive hypometabolism. Eight patients had newly developed macroglossia during the study and showed greater progression of communication impairment than those without macroglossia. Multivariate logistic regression analysis showed that communication impairment was a factor associated with macroglossia.

CONCLUSION

Macroglossia in advanced ALS with invasive ventilation is associated with disease progression.

Mutation-specific metabolic profiles in presymptomatic amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Growing evidence shows that ALS patients feature a disturbed energy metabolism. However, these features have rarely been investigated in the presymptomatic stage.

METHODS

A total of 60 presymptomatic ALS mutation carriers and 70 age- and gender-matched controls (non-mutation carriers from the same families) were recruited. All subjects underwent assessments of their metabolic profiles under fasting conditions at enrollment, including body mass index (BMI), blood pressure and serum levels of blood glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL) and low-density lipoprotein.

RESULTS

All mutations combined, no differences between presymptomatic ALS gene carriers and controls were found. From a cardiovascular point of view, presymptomatic chromosome 9 open reading frame 72 (C9ORF72) gene carriers showed lower cardiovascular risk profiles compared to healthy controls, including lower BMI (median 22.9, interquartile range [IQR] 20.6-26.1 kg/m² vs. 24.9, IQR 22.7-30.5 kg/m² ; p = 0.007), lower systolic blood pressure (120, IQR 110-130 mmHg vs. 128, IQR 120-140 mmHg; p = 0.02), lower fasting serum glucose (89.0, IQR 85.0-97.0 mg/dl vs. 96.0, IQR 89.3-102.0 mg/dl; p = 0.005) and higher HDL (1.6, IQR 1.3-1.8 mmol/l vs. 1.2, IQR 1.0-1.4 mmol/l; p = 0.04). However, presymptomatic superoxide dismutase 1 (SOD1) gene mutation carriers showed higher cardiovascular risk profiles compared to healthy controls, including higher BMI (28.0, IQR 26.1-31.5 kg/m² vs. 24.9, IQR 22.7-30.5 kg/m² ; p = 0.02), higher fasting serum glucose (100.0, IQR 94.0-117.0 mg/dl vs. 96.0, IQR 89.3-102.0 mg/dl; p = 0.04) and lower HDL (1.2, IQR 1.0-1.4 mmol/l vs. 1.4, IQR 1.2-1.7 mmol/l; p = 0.01). These features were most prominent in patients carrying SOD1 gene mutations associated with slow disease progression.

CONCLUSIONS

This study identified distinct metabolic profiles in presymptomatic ALS gene carriers, which might be associated with disease progression in the symptomatic phase.

Dietary-Derived Essential Nutrients and Amyotrophic Lateral Sclerosis: A Two-Sample Mendelian Randomization Study

Previous studies have suggested a close but inconsistent relationship between essential nutrients and the risk of amyotrophic lateral sclerosis (ALS), and whether this association is causal remains unknown. We aimed to investigate the potential causal relation between essential nutrients (essential amino acids, essential fatty acids, essential minerals, and essential vitamins) and the risk of ALS using Mendelian randomization (MR) analysis. Large-scale European-based genome-wide association studies' (GWASs) summary data related to ALS (assembling 27,205 ALS patients and 110,881 controls) and essential nutrient concentrations were separately obtained. MR analysis was performed using the inverse variance-weighted (IVW) method, and sensitivity analysis was conducted by the weighted median method, simple median method, MR-Egger method and MR-PRESSO method. We found a causal association between genetically predicted linoleic acid (LA) and the risk of ALS (OR: 1.066; 95% CI: 1.011-1.125; p = 0.019). An inverse association with ALS risk was noted for vitamin D (OR: 0.899; 95% CI: 0.819-0.987; p = 0.025) and for vitamin E (OR: 0.461; 95% CI: 0.340-0.626; p = 6.25 × 10^-7). The sensitivity analyses illustrated similar trends. No causal effect was observed between essential amino acids and minerals on ALS. Our study profiled the effects of diet-derived circulating nutrients on the risk of ALS and demonstrated that vitamin D and vitamin E are protective against the risk of ALS, and LA is a suggested risk factor for ALS.

Investigation of the prognostic predictive value of serum lipid profiles in amyotrophic lateral sclerosis: roles of sex and hypermetabolism

The prognostic predictive value of lipid profiling in amyotrophic lateral sclerosis (ALS) remains unclear. Here, we aimed to clarify the value of the levels of serum lipids, including high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), and triglycerides (TG), for predicting the prognosis in ALS. This was a single-center retrospective study of 78 patients with ALS. The serum lipid profiles at the first hospital visit after symptom onset were analyzed to determine the correlations of lipids with survival and physical parameters, including nutritional, respiratory, and metabolic conditions. The cutoff level for high HDL was defined as the third quartile, while that of low LDL and TG, as the first quartile. Hypermetabolism was defined as the ratio of resting energy expenditure to lean soft tissue mass ≥ 38 kcal/kg. High HDL was an independent factor for poor prognosis in all patients (hazards ratio [HR]: 9.87, p < 0.001) in the Cox proportional hazard model, including %vital capacity and the monthly decline rate in body mass index and the Revised Amyotrophic Lateral Functional Rating Scale score from symptom onset to diagnosis. Low LDL was a factor for poor prognosis (HR: 6.59, p = 0.017) only in women. Moreover, subgroup analyses with log-rank tests revealed that the prognostic predictive value of high HDL was evident only in the presence of hypermetabolism (p = 0.005). High HDL predicts poor prognosis in all patients, whereas low LDL, only in women. Hypermetabolism and high HDL synergistically augment the negative effect on prognosis.

Combined Treatment with Herbal Medicine and Drug Ameliorates Inflammation and Metabolic Abnormalities in the Liver of an Amyotrophic Lateral Sclerosis Mouse Model

To date, no effective drugs exist for amyotrophic lateral sclerosis (ALS), although riluzole (RZ) and edaravone have been approved for treatment. We previously reported that Bojungikgi-tang (BJIGT) improved motor activity through anti-inflammatory effects in the muscle and spinal cord of hSOD1^G93A mice. Therefore, whether combined treatment with BJIGT and RZ synergistically affects liver function in hSOD1^G93A mice was investigated. Two-month-old male hSOD1^G93A mice were treated with BJIGT (1 mg/g) and RZ (8 μg/g) administered orally for 5 weeks. Drug metabolism and liver function tests of serum and liver homogenates were conducted. mRNA expression levels of cytochrome P450 (CYP) isozymes, inflammatory cytokines, metabolic factors, and mitochondrial oxidative phosphorylation (OXPHOS) subunits were examined using qPCR and Western blotting. Combined administration of BJIGT and RZ did not alter mRNA expression levels of drug-metabolism-related isozymes (CYP1A2 and CYP3A4) but significantly decreased the activity of liver-function-related enzymes (AST, ALT, ALP, and LDH). Increased expression of inflammatory cytokines (IL-1β, TNF-α, and IL-6) and of intracellular stress-related proteins (Bax, AMPKα, JNK, and p38) was reduced by the combined treatment in hSOD1^G93A mice compared to that in control mice. Combined administration reduced the mRNA expression of metabolism-related factors and the expression of OXPHOS subunits. Elevated ATP levels and mitochondrial-fusion-associated protein were decreased after co-administration. Co-administration of BJIGT and RZ did not cause liver damage or toxicity but rather restored liver function in hSOD1^G93A mice. This suggests that this combination can be considered a candidate therapeutic agent for ALS.

Small fiber neuropathy for assessment of disease severity in amyotrophic lateral sclerosis: corneal confocal microscopy findings

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder with progressive motor system impairment, and recent evidence has identified the extra-motor involvement. Small fiber neuropathy reflecting by sensory and autonomic disturbances in ALS has been reported to accompany the motor damage. However, non-invasive assessment of this impairment and its application in disease evaluation of ALS is scarce. We aim to evaluate the use of corneal confocal microscopy (CCM) to non-invasively quantify the corneal small fiber neuropathy in ALS and explore its clinical value in assessing disease severity of ALS.

METHODS

Sixty-six patients with ALS and 64 healthy controls were included in this cross-sectional study. Participants underwent detailed clinical assessments and corneal imaging with in vivo CCM. Using ImageJ, the following parameters were quantified: corneal nerve length (IWL) and dendritic cell density (IWDC) in the inferior whorl region and corneal nerve fiber length (CNFL), nerve fiber density (CNFD), nerve branch density (CNBD), and dendritic cell density (CDC) in the peripheral region. Disease severity was evaluated using recognized scales.

RESULTS

Corneal nerve lengths (IWL and CNFL) were lower while dendritic cell densities (IWDC and CDC) were higher in patients with ALS than controls in peripheral and inferior whorl regions (p < 0.05). Additionally, corneal nerve complexity in the peripheral region was greater in patients than controls with higher CNBD (p = 0.040) and lower CNFD (p = 0.011). IWL was significantly associated with disease severity (p < 0.001) and progression (p = 0.002) in patients with ALS. Patients with bulbar involvement showed significantly lower IWL (p = 0.014) and higher IWDC (p = 0.043) than patients without bulbar involvement.

CONCLUSIONS

CCM quantified significant corneal neuropathy in ALS, and alterations in the inferior whorl region were closely associated with disease severity. CCM could serve as a noninvasive, objective imaging tool to detect corneal small fiber neuropathy for clinical evaluation in ALS.

Prognostic prediction by hypermetabolism varies depending on the nutritional status in early amyotrophic lateral sclerosis

To examine whether hypermetabolism could predict the prognosis of early amyotrophic lateral sclerosis (ALS) patients with differing nutritional profiles. This single-center, retrospective study examined the prognosis of ALS patients with hypermetabolism in relation to their nutritional status at hospitalization. The metabolic state was estimated by the ratio of measured resting energy expenditure (mREE) to lean soft tissue mass (LSTM) (mREE/LSTM), wherein patients with ratios ≥ 38 were defined as hypermetabolic. Malnutrition was defined as %ideal body weight < 0.9. Forty-eight patients were enrolled in this study. The hypermetabolic group had shorter survival in the normal-weight group but more prolonged survival in the malnutrition group. Multiplication of nutritional and metabolic factors, such as [(body mass index (BMI) − 19.8) × (mREE/LSTM − 38)], designated as BMI-muscle metabolism index (BMM index), successfully predicted the prognosis in the group with a high BMM index (≥ 1), which showed shorter survival and a faster rate of weight loss and functional decline. Multivariate analysis using the Cox model showed high BMM index was an independent poor prognostic factor (hazard ratio: 4.05; p = 0.025). Prognostic prediction by hypermetabolism varies depending on the nutritional status in ALS, and the BMM index is a consistent prognostic factor.