Blood biomarkers of carbohydrate, lipid, and apolipoprotein metabolisms and risk of amyotrophic lateral sclerosis: A more than 20-year follow-up of the Swedish AMORIS cohort

Lipidomic traits of plasma and cerebrospinal fluid in amyotrophic lateral sclerosis correlate with disease progression

Since amyotrophic lateral sclerosis cases exhibit significant heterogeneity, we aim to investigate the association of lipid composition of plasma and CSF with amyotrophic lateral sclerosis diagnosis, its progression and clinical characteristics. Lipidome analyses would help to stratify patients on a molecular basis. For this reason, we have analysed the lipid composition of paired plasma and CSF samples from amyotrophic lateral sclerosis cases and age-matched non-amyotrophic lateral sclerosis individuals (controls) by comprehensive liquid chromatography coupled to mass spectrometry. The concentrations of neurofilament light chain-an index of neuronal damage-were also quantified in CSF samples and plasma. Amyotrophic lateral sclerosis versus control comparison, in a moderate stringency mode, showed that plasma from cases contains more differential lipids (n = 122 for raw P < 0.05; n = 27 for P < 0.01) than CSF (n = 17 for raw P < 0.05; n = 4 for P < 0.01), with almost no overlapping differential species, mainly characterized by an increased content of triacylglyceride species in plasma and decreased in CSF. Of note, false discovery rate correction indicated that one of the CSF lipids (monoacylglycerol 18:0) had high statistic robustness (false discovery rate-P < 0.01). Plasma lipidomes also varied significantly with the main involvement at onset (bulbar, spinal or respiratory). Notably, faster progression cases showed particular lipidome fingerprints, featured by decreased triacylclycerides and specific phospholipids in plasma, with 11 lipids with false discovery rate-P < 0.1 (n = 56 lipids in plasma for raw P < 0.01). Lipid species associated with progression rate clustered in a relatively low number of metabolic pathways, mainly triacylglyceride metabolism and glycerophospholipid and sphingolipid biosynthesis. A specific triacylglyceride (68:12), correlated with neurofilament content (r = 0.8, P < 0.008). Thus, the present findings suggest that systemic hypermetabolism-potentially sustained by increased triacylglyceride content-and CNS alterations of specific lipid pathways could be associated as modifiers of disease progression. Furthermore, these results confirm biochemical lipid heterogeneity in amyotrophic lateral sclerosis with different presentations and progression, suggesting the use of specific lipid species as potential disease classifiers.

Diabetes Mellitus and Amyotrophic Lateral Sclerosis: A Systematic Review

BACKGROUND

Amyotrophic Lateral Sclerosis (ALS) is a degenerative disorder which affects the motor neurons. Growing evidence suggests that ALS may impact the metabolic system, including the glucose metabolism. Several studies investigated the role of Diabetes Mellitus (DM) as risk and/or prognostic factor. However, a clear correlation between DM and ALS has not been defined. In this review, we focus on the role of DM in ALS, examining the different hypotheses on how perturbations of glucose metabolism may interact with the pathophysiology and the course of ALS.

METHODS

We undertook an independent PubMed literature search, using the following search terms: ((ALS) OR (Amyotrophic Lateral Sclerosis) OR (Motor Neuron Disease)) AND ((Diabetes) OR (Glucose Intolerance) OR (Hyperglycemia)). Review and original articles were considered.

RESULTS

DM appears not to affect ALS severity, progression, and survival. Contrasting data suggested a protective role of DM on the occurrence of ALS in elderly and an opposite effect in younger subjects.

CONCLUSIONS

The actual clinical and pathophysiological correlation between DM and ALS is unclear. Large longitudinal prospective studies are needed. Achieving large sample sizes comparable to those of common complex diseases like DM is a challenge for a rare disease like ALS. Collaborative efforts could overcome this specific issue.

Pathophysiology and Treatment of Non-motor Dysfunction in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive and fatal neurodegenerative disease typically presenting with bulbar or limb weakness. There is increasing evidence that amyotrophic lateral sclerosis is a multisystem disease with early and frequent impacts on cognition, behaviour, sleep, pain and fatigue. Dysfunction of normal physiological and metabolic processes also appears common. Evidence from pre-symptomatic studies and large epidemiological cohorts examining risk factors for the future development of amyotrophic lateral sclerosis have reported a high prevalence of changes in behaviour and mental health before the emergence of motor weakness. This suggests that changes beyond the motor system are underway at an early stage with dysfunction across brain networks regulating a variety of cognitive, behavioural and other homeostatic processes. The full impact of non-motor dysfunction continues to be established but there is now sufficient evidence that the presence of non-motor symptoms impacts overall survival in amyotrophic lateral sclerosis, and with up to 80% reporting non-motor symptoms, there is an urgent need to develop more robust therapeutic approaches. This review provides a contemporary overview of the pathobiology of non-motor dysfunction, offering readers a practical approach with regard to assessment and management. We review the current evidence for pharmacological and non-pharmacological treatment of non-motor dysfunction in amyotrophic lateral sclerosis and highlight the need to further integrate non-motor dysfunction as an important outcome measure for future clinical trial design.

Downregulating carnitine palmitoyl transferase 1 affects disease progression in the SOD1 G93A mouse model of ALS

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease characterized by death of motor neurons. The etiology and pathogenesis remains elusive despite decades of intensive research. Herein, we report that dysregulated metabolism plays a central role in the SOD1 G93A mouse model mimicking ALS. Specifically, we report that the activity of carnitine palmitoyl transferase 1 (CPT1) lipid metabolism is associated with disease progression. Downregulation of CPT1 activity by pharmacological and genetic methods results in amelioration of disease symptoms, inflammation, oxidative stress and mitochondrial function, whereas upregulation by high-fat diet or corticosterone results in a more aggressive disease progression. Finally, we show that downregulating CPT1 shifts the gut microbiota communities towards a protective phenotype in SOD1 G93A mice. These findings reveal that metabolism, and specifically CPT1 lipid metabolism plays a central role in the SOD1 G93A mouse model and shows that CPT1 might be a therapeutic target in ALS.

Muscle Function Differences between Patients with Bulbar and Spinal Onset Amyotrophic Lateral Sclerosis. Does It Depend on Peripheral Glucose?

BACKGROUND

One of the pathogenic mechanisms of ALS disease is perturbed energy metabolism particularly glucose metabolism. Given the substantial difference in the severity and the prognosis of the disease, depending on whether it has a bulbar or spinal onset, the aim of the study was to determine metabolic differences between both types of ALS, as well as the possible relationship with muscle function.

MATERIALS AND METHODS

A descriptive, analytical, quantitative, and transversal study was carried out in hospitals and Primary Care centers in the region of Valencia, Spain. Fasting glucose and alkaline phosphatase (AP) levels in venous blood, muscle percentage, fat percentage, muscle strength (MRC scale), and functional capacity (Barthel Index) were measured in 31 patients diagnosed with ALS (20 with spinal onset ALS and 11 with bulbar onset ALS). A healthy control of 29 people was included.

RESULTS

No significant differences were observed in blood AP and glucose levels between spinal onset and bulbar onset ALS patients. However, a significant positive correlation was observed between the mean values of both substances in patients with spinal onset ALS. Moreover, a lower percentage of muscle mass and a higher percentage of fat mass were also seen in spinal ALS patients, who also presented lower muscle strength and lower functional capacity.

CONCLUSION

The results of this study seem to point to a possible difference in the peripheral use of glucose between patients with bulbar onset ALS and spinal onset ALS, who appear to have possible insulin resistance. These metabolic differences could explain the lower muscle percentage and lower muscular function in spinal onset ALS patients, although further studies are required.

Network Analysis of the CSF Proteome Characterizes Convergent Pathways of Cellular Dysfunction in ALS

BACKGROUND

Amyotrophic lateral sclerosis is a clinical syndrome with complex biological determinants, but which in most cases is characterized by TDP-43 pathology. The identification in CSF of a protein signature of TDP-43 network dysfunction would have the potential to inform the identification of new biomarkers and therapeutic targets.

METHODS

We compared CSF proteomic data from patients with ALS (n = 41), Parkinson's disease (n = 19) and healthy control participants (n = 20). Weighted correlation network analysis was used to identify modules within the CSF protein network and combined with gene ontology enrichment analysis to functionally annotate module proteins. Analysis of module eigenproteins and differential correlation analysis of the CSF protein network was used to compare ALS and Parkinson's disease protein co-correlation with healthy controls. In order to monitor temporal changes in the CSF proteome, we performed longitudinal analysis of the CSF proteome in a subset of ALS patients.

RESULTS

Weighted correlation network analysis identified 10 modules, including those enriched for terms involved in gene expression including nucleic acid binding, RNA metabolism and translation; humoral immune system function, including complement pathways; membrane proteins, axonal outgrowth and adherence; and glutamatergic synapses. Immune system module eigenproteins were increased in ALS, whilst axonal module eigenproteins were decreased in ALS. The 19 altered protein correlations in ALS were enriched for gene expression (OR 3.05, p = 0.017) and membrane protein modules (OR 17.48, p = 0.011), including intramodular hub proteins previously identified as TDP-43 interactors. Proteins decreasing over longitudinal analysis ALS were enriched in glutamatergic synapse and axonal outgrowth modules. Protein correlation network disruptions in Parkinson's disease showed no module enrichment.

CONCLUSIONS

Alterations in the co-correlation network in CSF samples identified a set of pathways known to be associated with TDP-43 dysfunction in the pathogenesis of ALS, with important implications for therapeutic targeting and biomarker development.

Gastrointestinal biopsies and amyotrophic lateral sclerosis - results from a cohort study of 1.1 million individuals

Background: Evidence has accumulated to support the involvement of gastrointestinal (GI) dysfunction, possibly via gut microbial dysbiosis and alterations in the enteric nervous system, in the pathophysiology of different neurodegenerative diseases. However, whether patients with GI dysfunction have altered risk of amyotrophic lateral sclerosis (ALS) remains unknown.Methods: Based on a historical nationwide cohort study-ESPRESSO-in Sweden, we compared the risk of ALS among individuals with a previous GI biopsy finding of normal mucosa or non-specific inflammation, as two conditions of GI dysfunction, to that of individuals without any GI biopsy. We identified all individuals with a GI biopsy result of either normal mucosa (n = 483,442) or non-specific inflammation (n = 566,663) during 1965-2016 in Sweden as the exposed groups. For each exposed individual, we randomly selected up to five controls from the general Swedish population after individual matching by age and sex. Both the exposed and unexposed individuals were followed from date of biopsy (exposed individuals) or date of selection (unexposed individuals) until ALS diagnosis, emigration out of Sweden, death, or 31 December 2016, whichever came first. Stratified Cox regression models were used to estimate hazard ratios (HRs) and their 95% confidence intervals (CIs).Results: Compared to individuals without GI biopsy, individuals with a GI biopsy result of normal mucosa had an increased risk of ALS (HR = 1.22; 95%CI: 1.04-1.42) after excluding the first 2 years of follow-up to alleviate concern of surveillance bias. This increased risk was noted among male (HR = 1.20; 95%CI: 0.94-1.51) and female (HR = 1.23; 95%CI: 1.01-1.50), as well as among younger (<60 years; HR = 1.17; 95%CI: 0.94-1.44) and older (≥60 years; HR = 1.24; 95%CI: 0.99-1.56) individuals. In contrast, no association was observed for a GI biopsy result of non-specific inflammation (HR = 1.00; 95%CI: 0.88-1.15). Neither of the GI biopsy results was related to the mortality risk after ALS diagnosis.Conclusions: Individuals with a GI biopsy result of normal mucosa-representing potentially a distinct type of GI dysfunction-had a higher future risk of ALS. No association was however noted for a GI biopsy result of non-specific inflammation. Further studies are needed to validate this finding and to understand the underlying reasons for the contrasting result pattern.

Association of Stress-Related Disorders With Subsequent Neurodegenerative Diseases

Importance

Posttraumatic stress disorder (PTSD) has been associated with increased risk for dementia. Less is known, however, about other stress-related disorders and their associations with neurodegenerative diseases.

Objective

To examine the association between stress-related disorders and risk for neurodegenerative diseases.

Design, Setting, and Participants

This population-matched and sibling cohort study was conducted in Sweden using data from nationwide health registers, including the Swedish National Patient Register. Individuals who received their first diagnosis of stress-related disorders between January 1, 1987, and December 31, 2008, were identified. Individuals who had a history of neurodegenerative diseases, had conflicting or missing information, had no data on family links, or were aged 40 years or younger at the end of the study were excluded. Individuals with stress-related disorders were compared with the general population in a matched cohort design; they were also compared with their siblings in a sibling cohort. Follow-up commenced from the age of 40 years or 5 years after the diagnosis of stress-related disorders, whichever came later, until the first diagnosis of a neurodegenerative disease, death, emigration, or the end of follow-up (December 31, 2013), whichever occurred first. Data analyses were performed from November 2018 to April 2019.

Exposures

Diagnosis of stress-related disorders (PTSD, acute stress reaction, adjustment disorder, and other stress reactions).

Main Outcomes and Measurements

Neurodegenerative diseases were identified through the National Patient Register and classified as primary or vascular. Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis were evaluated separately. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) with 95% CIs after controlling for multiple confounders.

Results

The population-matched cohort included 61 748 exposed individuals and 595 335 matched unexposed individuals. A total of 44 839 exposed individuals and their 78 482 unaffected full siblings were included in the sibling cohort analysis. The median (interquartile range) age at the start of follow-up was 47 (41-56) years, and 24 323 (39.4%) of the exposed individuals were male. The median (interquartile range) follow-up was 4.7 (2.1-9.8) years. Compared with unexposed individuals, individuals with a stress-related disorder were at an increased risk of neurodegenerative diseases (HR, 1.57; 95% CI, 1.43-1.73). The risk increase was greater for vascular neurodegenerative diseases (HR, 1.80; 95% CI, 1.40-2.31) than for primary neurodegenerative diseases (HR, 1.31; 95% CI, 1.15-1.48). A statistically significant association was found for Alzheimer disease (HR, 1.36; 95% CI, 1.12-1.67) but not Parkinson disease (HR, 1.20; 95% CI, 0.98-1.47) or amyotrophic lateral sclerosis (HR, 1.20; 95% CI, 0.74-1.96). Results from the sibling cohort corroborated results from the population-matched cohort.

Conclusions and Relevance

This study showed an association between stress-related disorders and an increased risk of neurodegenerative diseases. The relative strength of this association for vascular neurodegenerative diseases suggests a potential cerebrovascular pathway.

Improving clinical trial outcomes in amyotrophic lateral sclerosis

Individuals who are diagnosed with amyotrophic lateral sclerosis (ALS) today face the same historically intransigent problem that has existed since the initial description of the disease in the 1860s - a lack of effective therapies. In part, the development of new treatments has been hampered by an imperfect understanding of the biological processes that trigger ALS and promote disease progression. Advances in our understanding of these biological processes, including the causative genetic mutations, and of the influence of environmental factors have deepened our appreciation of disease pathophysiology. The consequent identification of pathogenic targets means that the introduction of effective therapies is becoming a realistic prospect. Progress in precision medicine, including genetically targeted therapies, will undoubtedly change the natural history of ALS. The evolution of clinical trial designs combined with improved methods for patient stratification will facilitate the translation of novel therapies into the clinic. In addition, the refinement of emerging biomarkers of therapeutic benefits is critical to the streamlining of care for individuals. In this Review, we synthesize these developments in ALS and discuss the further developments and refinements needed to accelerate the introduction of effective therapeutic approaches.

Sterol auto-oxidation adversely affects human motor neuron viability and is a neuropathological feature of amyotrophic lateral sclerosis

Aberrant cholesterol homeostasis is implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), a fatal neuromuscular disease that is due to motor neuron (MN) death. Cellular toxicity from excess cholesterol is averted when it is enzymatically oxidized to oxysterols and bile acids (BAs) to promote its removal. In contrast, the auto oxidation of excess cholesterol is often detrimental to cellular survival. Although oxidized metabolites of cholesterol are altered in the blood and CSF of ALS patients, it is unknown if increased cholesterol oxidation occurs in the SC during ALS, and if exposure to oxidized cholesterol metabolites affects human MN viability. Here, we show that in the SOD1^G93A mouse model of ALS that several oxysterols, BAs and auto oxidized sterols are increased in the lumbar SC, plasma, and feces during disease. Similar changes in cholesterol oxidation were found in the cervical SC of sporadic ALS patients. Notably, auto-oxidized sterols, but not oxysterols and BAs, were toxic to iPSC derived human MNs. Thus, increased cholesterol oxidation is a manifestation of ALS and non-regulated sterol oxidation likely contributes to MN death. Developing therapeutic approaches to restore cholesterol homeostasis in the SC may lead to a treatment for ALS.

Aberrations of biochemical indicators in amyotrophic lateral sclerosis: a systematic review and meta-analysis

Accumulating evidence has suggested that the pathological changes in amyotrophic lateral sclerosis (ALS) are not only confined to the central nervous system but also occur in the peripheral circulating system. Here, we performed a meta-analysis based on the PubMed, EMBASE, EBSCO, and CNKI databases, to find out biochemical indicators associated with energy metabolism, iron homeostasis, and muscle injury that are altered in ALS patients and their correlations with ALS phenotypes. Forty-six studies covering 17 biochemical indicators, representing 5454 ALS patients and 7986 control subjects, were included in this meta-analysis. Four indicators, including fasting blood glucose level (weighted mean difference [WMD] = 0.13, 95% CI [0.06–0.21], p = 0.001), serum ferritin level (WMD = 63.42, 95% CI [48.12–78.73], p < 0.001), transferrin saturation coefficient level (WMD = 2.79, 95% CI [1.52–4.05], p < 0.001), and creatine kinase level (WMD = 80.29, 95% CI [32.90–127.67], p < 0.001), were significantly higher in the ALS patients, whereas the total iron-binding capacity (WMD = − 2.42, 95% CI [− 3.93, − 0.90], p = 0.002) was significantly lower in ALS patients than in the control subjects. In contrast, the other 12 candidates did not show significant differences between ALS patients and controls. Moreover, pooled hazard ratios (HR) showed significantly reduced survival (HR = 1.38, 95% CI [1.02–1.88], p = 0.039) of ALS patients with elevated serum ferritin levels. These findings suggest that abnormalities in energy metabolism and disruption of iron homeostasis are involved in the pathogenesis of ALS. In addition, the serum ferritin level is negatively associated with the overall survival of ALS patients.

Hypothalamic symptoms of frontotemporal dementia disorders

Frontotemporal dementia (FTD) has traditionally been regarded as a disease of cognition and behavior, but emerging evidence suggests that the disease also affects body functions including changes in eating behavior and metabolism, autonomic function, sleep behavior, and sexual function. Central to these changes are potentially complex neural networks involving the hypothalamus, with hypothalamic atrophy shown in behavioral variant FTD. The physiological changes found in FTD are reviewed and the key neural networks and neuroendocrine changes mediating these changes in function discussed, including the ability to use these changes as biomarkers to aid in disease diagnosis, monitoring disease progression, and as potential treatment targets.

Behavioural Variant Frontotemporal Dementia: Recent Advances in the Diagnosis and Understanding of the Disorder

Frontotemporal dementia (FTD), particularly the behavioural variant (bvFTD) form, has fascinated researchers. Recent years have seen an increasing interest in aspects of bvFTD that extend beyond the initial focus on cognitive changes and frontal executive dysfunction. Changes have been identified in aspects including fundamental changes in physiology and metabolism, and cognitive domains such as episodic memory. Work on social cognition has emphasised the importance of a breakdown in interpreting and expressing emotions, while the overlap between psychiatric disorders and bvFTD has been brought into focus by the finding of high rates of psychotic features in carriers of the c9orf72 gene expansion. We review these aspects in the chapter " Behavioural variant frontotemporal dementia: Recent advances in diagnosis and understanding of the disorder" and also potential markers of disease progression and early diagnosis that may aid in the development of treatment options, which have thus far eluded us.

Paraoxonase Role in Human Neurodegenerative Diseases

The human body has biological redox systems capable of preventing or mitigating the damage caused by increased oxidative stress throughout life. One of them are the paraoxonase (PON) enzymes. The PONs genetic cluster is made up of three members (PON1, PON2, PON3) that share a structural homology, located adjacent to chromosome seven. The most studied enzyme is PON1, which is associated with high density lipoprotein (HDL), having paraoxonase, arylesterase and lactonase activities. Due to these characteristics, the enzyme PON1 has been associated with the development of neurodegenerative diseases. Here we update the knowledge about the association of PON enzymes and their polymorphisms and the development of multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Parkinson's disease (PD).

Associations between autoimmune diseases and amyotrophic lateral sclerosis: a register-based study

Objective: To assess the associations of 43 autoimmune diseases with the subsequent risk of ALS and further evaluate the contribution of familial confounding to these associations.Methods: We conducted a nationwide register-based nested case-control study including 3561 ALS patients diagnosed during 1990-2013 in Sweden and 35,610 controls that were randomly selected from the general population and individually matched to the cases on age, sex, and county of birth. To evaluate the contribution of familial factors on the studied association, we additionally studied the first-degree relatives (siblings and children) of ALS patients and their controls.Results: Patients with ALS had a 47% higher risk of being previously diagnosed with autoimmune disease (OR 1.47, 95% confidence interval [CI] 1.31-1.64), compared with controls. A positive association was noted for several autoimmune diseases, including myasthenia gravis, polymyositis or dermatomyositis, Guillain-Barre syndrome, type 1 diabetes diagnosed younger than 30 years, multiple sclerosis, and hypothyreosis. The increased risk of any autoimmune disease was greatest during the year before ALS diagnosis, likely due to misdiagnosis. A statistically significantly increased risk was also noted during 2-5 years, but not earlier, before ALS diagnosis. First-degree relatives of ALS patients had however no increased risk of autoimmune diseases compared with first-degree relatives of controls.Conclusions: Although it is difficult to completely remove the potential effects of misdiagnosis, there is likely a positive association between autoimmune disease (such as type 1 diabetes and multiple sclerosis) and ALS, which is not fully explained by shared familial confounding factors.

Low Serum High-Density Lipoprotein Cholesterol Levels Associate with the C9orf72 Repeat Expansion in Frontotemporal Lobar Degeneration Patients

 Decreased levels of serum high-density lipoprotein (HDL) cholesterol have previously been linked to systemic inflammation and neurodegenerative diseases, such as Alzheimer’s disease. Here, we aimed to analyze the lipoprotein profile and inflammatory indicators, the high-sensitivity C-reactive peptide (hs-CRP) and glycoprotein acetyls (GlycA), in sporadic and C9orf72 repeat expansion-associated frontotemporal lobar degeneration (FTLD) patients. The C9orf72 hexanucleotide repeat expansion is the most frequent genetic etiology underlying FTLD. The concentrations of different lipid measures in the sera of 67 FTLD patients (15 C9orf72 repeat expansion carriers), including GlycA, were analyzed by nuclear magnetic resonance spectroscopy. To verify the state of systemic inflammation, hs-CRP was also quantified from patient sera. We found that the total serum HDL concentration was decreased in C9orf72 repeat expansion carriers when compared to non-carriers. Moreover, decreased concentrations of HDL particles of different sizes and subclass were consistently observed. No differences were detected in the very low- and low-density lipoprotein subclasses between the C9orf72 repeat expansion carriers and non-carriers. Furthermore, hs-CRP and GlycA levels did not differ between the C9orf72 repeat expansion carriers and non-carriers. In conclusion, the HDL-related changes were linked with C9orf72 repeat expansion associated FTLD but were not seen to associate with systemic inflammation. The underlying reason for the HDL changes remains unclear.

Endocannabinoids and related lipids in serum from patients with amyotrophic lateral sclerosis

BACKGROUND

The goals of this study were to determine whether serum concentrations of endocannabinoids (eCB) and related lipids predict disease status in patients with amyotrophic lateral sclerosis (ALS) relative to healthy controls, and whether concentrations correlate with disease duration and severity.

METHODS

Serum concentrations of the eCBs 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA), and related lipids palmitoylethanolamine (PEA), oleoylethanolamine (OEA), and 2-oleoylglycerol (2-OG), were measured in samples from 47 patients with ALS and 19 healthy adults. Hierarchical binary logistic and linear regression analyses assessed whether lipid concentrations predicted disease status (ALS or healthy control), duration, or severity.

RESULTS

Binary logistic regression revealed that, after controlling for age and gender, 2-AG, 2-OG and AEA concentrations were unique predictors of the presence of ALS, demonstrating odds ratios of 0.86 (P = .039), 1.03 (P = .023), and 42.17 (P = .026), respectively. When all five lipids and covariates (age, sex, race, ethnicity, body mass index, presence of a feeding tube) were included, the resulting model had an overall classification accuracy of 92.9%. Hierarchical linear regression analyses indicated that in patients with ALS, AEA and OEA inversely correlated with disease duration (P = .030 and .031 respectively), while PEA demonstrated a positive relationship with disease duration (P = .013). None of the lipids examined predicted disease severity.

CONCLUSIONS

These findings support previous studies indicating significant alterations in concentrations of circulating lipids in patients with ALS. They suggest that arachidonic and oleic acid containing small lipids may serve as biomarkers for identifying the presence and duration of this disease.

Neutral Lipid Cacostasis Contributes to Disease Pathogenesis in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disease characterized by motor neuron (MN) death. Lipid dysregulation manifests during disease; however, it is unclear whether lipid homeostasis is adversely affected in the in the spinal cord gray matter (GM), and if so, whether it is because of an aberrant increase in lipid synthesis. Moreover, it is unknown whether lipid dysregulation contributes to MN death. Here, we show that cholesterol ester (CE) and triacylglycerol levels are elevated several-fold in the spinal cord GM of male sporadic ALS patients. Interestingly, HMG-CoA reductase, the rate-limiting enzyme in cholesterol synthesis, was reduced in the spinal cord GM of ALS patients. Increased cytosolic phospholipase A2 activity and lyso-phosphatidylcholine (Lyso-PC) levels in ALS patients suggest that CE accumulation was driven by acyl group transfer from PC to cholesterol. Notably, Lyso-PC, a byproduct of CE synthesis, was toxic to human MNs in vitro Elevations in CE, triacylglycerol, and Lyso-PC were also found in the spinal cord of SOD1^G93A mice, a model of ALS. Similar to ALS patients, a compensatory downregulation of cholesterol synthesis occurred in the spinal cord of SOD1^G93A mice; levels of sterol regulatory element binding protein 2, a transcriptional regulator of cholesterol synthesis, progressively declined. Remarkably, overexpressing sterol regulatory element binding protein 2 in the spinal cord of normal mice to model CE accumulation led to ALS-like lipid pathology, MN death, astrogliosis, paralysis, and reduced survival. Thus, spinal cord lipid dysregulation in ALS likely contributes to neurodegeneration and developing therapies to restore lipid homeostasis may lead to a treatment for ALS.SIGNIFICANCE STATEMENT Neurons that control muscular function progressively degenerate in patients with amyotrophic lateral sclerosis (ALS). Lipid dysregulation is a feature of ALS; however, it is unclear whether disrupted lipid homeostasis (i.e., lipid cacostasis) occurs proximal to degenerating neurons in the spinal cord, what causes it, and whether it contributes to neurodegeneration. Here we show that lipid cacostasis occurs in the spinal cord gray matter of ALS patients. Lipid accumulation was not associated with an aberrant increase in synthesis or reduced hydrolysis, as enzymatic and transcriptional regulators of lipid synthesis were downregulated during disease. Last, we demonstrated that genetic induction of lipid cacostasis in the CNS of normal mice was associated with ALS-like lipid pathology, astrogliosis, neurodegeneration, and clinical features of ALS.

Diet, Microbiota and Brain Health: Unraveling the Network Intersecting Metabolism and Neurodegeneration

Increasing evidence gives support for the idea that extra-neuronal factors may affect brain physiology and its predisposition to neurodegenerative diseases. Epidemiological and experimental studies show that nutrition and metabolic disorders such as obesity and type 2 diabetes increase the risk of Alzheimer's and Parkinson's diseases after midlife, while the relationship with amyotrophic lateral sclerosis is uncertain, but suggests a protective effect of features of metabolic syndrome. The microbiota has recently emerged as a novel factor engaging strong interactions with neurons and glia, deeply affecting their function and behavior in these diseases. In particular, recent evidence suggested that gut microbes are involved in the seeding of prion-like proteins and their spreading to the central nervous system. Here, we present a comprehensive review of the impact of metabolism, diet and microbiota in neurodegeneration, by affecting simultaneously several aspects of health regarding energy metabolism, immune system and neuronal function. Advancing technologies may allow researchers in the future to improve investigations in these fields, allowing the buildup of population-based preventive interventions and development of targeted therapeutics to halt progressive neurologic disability.

Pre-diagnostic plasma lipid levels and the risk of amyotrophic lateral sclerosis

OBJECTIVE

To assess whether pre-diagnostic lipid levels are associated with Amyotrophic lateral sclerosis (ALS) risk. Methods: We conducted a matched case-control study nested in five large prospective US cohorts (the Nurses' Health Study, the Health Professionals Follow-up Study, the Cancer Prevention Study II Nutrition Cohort, the Multiethnic Cohort Study, and the Women's Health Initiative), and identified 275 individuals who developed ALS during follow-up and had provided blood samples before disease diagnosis. For each ALS case, we randomly selected two controls who were alive at the time of the case diagnosis and matched on cohort, birth year (±1 year), sex, race/ethnicity, fasting status, and time of blood draw. We measured total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) levels in the plasma samples, and used conditional logistic regression to estimate associations between lipid levels and ALS risk. Results: Higher levels of HDL-C were associated with higher ALS risk in an analysis adjusted for the matching factors (risk ratio [RR] Q4 vs. Q1: 1.78, 95% confidence interval [CI]: 1.18-2.69, p trend: 0.007). The estimate remained similar in a multivariable analysis additionally adjusted for body mass index, physical activity, smoking, alcohol intake, plasma urate levels, and use of cholesterol-lowering drugs (RR Q4 vs. Q1: 1.71, 95% CI: 1.07-2.73, p trend: 0.02). Plasma levels of TC, LDL-C, and TG were not associated with ALS risk. Conclusions: Higher pre-diagnostic HDL-C levels, but not levels of other lipids, were associated with a higher risk of ALS.

A multi-ethnic meta-analysis identifies novel genes, including ACSL5, associated with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating progressive motor neuron disease that affects people of all ethnicities. Approximately 90% of ALS cases are sporadic and thought to have multifactorial pathogenesis. To understand the genetics of sporadic ALS, we conducted a genome-wide association study using 1,173 sporadic ALS cases and 8,925 controls in a Japanese population. A combined meta-analysis of our Japanese cohort with individuals of European ancestry revealed a significant association at the ACSL5 locus (top SNP p = 2.97 × 10⁻⁸). We validated the association with ACSL5 in a replication study with a Chinese population and an independent Japanese population (1941 ALS cases, 3821 controls; top SNP p = 1.82 × 10⁻⁴). In the combined meta-analysis, the intronic ACSL5 SNP rs3736947 showed the strongest association (p = 7.81 × 10⁻¹¹). Using a gene-based analysis of the full multi-ethnic dataset, we uncovered additional genes significantly associated with ALS: ERGIC1, RAPGEF5, FNBP1, and ATXN3. These results advance our understanding of the genetic basis of sporadic ALS.

Gen Sobue, Masao Nagasaki and colleagues report a genome-wide association study for amyotrophic lateral sclerosis (ALS) in a large, multi-ethnic cohort comprising Japanese, Chinese, and European ancestry populations. They find a significant association to variants within the ACSL5 gene and identify novel associations with 4 additional genes using a gene-based approach.

The role of lipids in the central nervous system and their pathological implications in amyotrophic lateral sclerosis

Lipids play an important role in the central nervous system (CNS). They contribute to the structural integrity and physical characteristics of cell and organelle membranes, act as bioactive signalling molecules, and are utilised as fuel sources for mitochondrial metabolism. The intricate homeostatic mechanisms underpinning lipid handling and metabolism across two major CNS cell types; neurons and astrocytes, are integral for cellular health and maintenance. Here, we explore the various roles of lipids in these two cell types. Given that changes in lipid metabolism have been identified in a number of neurodegenerative diseases, we also discuss changes in lipid handling and utilisation in the context of amyotrophic lateral sclerosis (ALS), in order to identify key cellular processes affected by the disease, and inform future areas of research.

Creatinine and C-reactive protein in amyotrophic lateral sclerosis, multiple sclerosis and Parkinson's disease

Serum creatinine and C-reactive protein have been proposed as potential biomarkers for neurodegenerative diseases, including amyotrophic lateral sclerosis, multiple sclerosis and Parkinson’s disease. However, longitudinal studies investigating temporal patterns of these biomarkers, including the phase before diagnosis, are rare. We performed a case–control study including all newly diagnosed patients with amyotrophic lateral sclerosis (N = 525), multiple sclerosis (N = 1815) or Parkinson’s disease (N = 3797) during 2006–2013 in Stockholm, Sweden, who participated in the Stockholm CREAtinine Measurements (SCREAM) project. For each case, we randomly selected up to five controls from SCREAM that were individually matched to the case by age, sex and county of residence (N = 2625 for amyotrophic lateral sclerosis, N = 9063 for multiple sclerosis and 18 960 for Parkinson’s disease). We collected for both the cases and the controls testing results of serum creatinine and C-reactive protein performed by healthcare providers in Stockholm during the study period. Median levels of creatinine and C-reactive protein were visualized using locally weighted smoothing curves among cases and controls. A linear mixed model was also applied to explore temporal changes within an individual. Compared to controls, patients with amyotrophic lateral sclerosis had lower levels of creatinine from 2 years before diagnosis onwards. In contrast, patients with amyotrophic lateral sclerosis had lower levels of C-reactive protein before diagnosis but higher levels after diagnosis, compared to controls. Focusing the 2 years before to 2 years after diagnosis, patients with amyotrophic lateral sclerosis displayed statistically significantly decreasing level of creatinine from 1 year before diagnosis until 2 years after diagnosis, whereas increasing level of C-reactive protein from diagnosis until 2 years after diagnosis. There were no similar patterns noted among patients with multiple sclerosis or Parkinson’s disease, or the controls of the three patient groups. Patients with amyotrophic lateral sclerosis display distinct temporal patterns of creatinine and C-reactive protein before and after diagnosis, compared to amyotrophic lateral sclerosis-free controls or patients with multiple sclerosis and Parkinson’s disease.

No association between proton pump inhibitor use and ALS risk: a nationwide nested case-control study

The use of proton pump inhibitors (PPIs) has been proposed as a potential risk factor for neurodegenerative diseases, but little is known regarding its role in amyotrophic lateral sclerosis (ALS). We therefore aimed to assess the association of PPI use with the subsequent risk of ALS, and performed a register-based nationwide nested case–control study, including 2,484 ALS cases diagnosed during July 2006–December 2013 in Sweden and 10 population controls per case that were individually matched to the case by sex, age, and area of residence. Dispenses and cumulative defined daily doses (cDDDs) of PPIs were extracted from the Swedish Prescribed Drug Register. The association of PPI use with the risk of ALS was assessed using conditional logistic regression, after applying different lag windows to avoid reverse causation. ALS patients were more likely to be dispensed with PPIs before diagnosis than controls. However, previous PPI use was not associated with an increased risk of ALS (OR = 1.08, 95% CI 0.97–1.19), and there was no dose–response relationship between cDDDs of PPIs and ALS risk (p = 0.0874), after excluding dispenses during the year before ALS diagnosis. The results were similar after excluding dispenses during the 2 or 3 years before ALS diagnosis.

Statins, diabetes mellitus and prognosis of amyotrophic lateral sclerosis: data from 501 patients of a population-based registry in southwest Germany

BACKGROUND AND PURPOSE

A wide variety of metabolic changes, including an increased incidence of diabetes mellitus (DM) and dyslipidaemia, has been described in amyotrophic lateral sclerosis (ALS). The aim of this study was to investigate the associations of statin use and history of DM with onset of disease and survival in patients with ALS.

METHODS

In all, 501 patients (mean age 65.2 ± 10.9 years; 58.5% male) from the ALS Registry Swabia recruited between October 2010 and April 2016 were included in this prospective cohort study. Data were collected using a standardized questionnaire.

RESULTS

Statin use (n = 65) was not associated with overall survival (P = 0.62). Age of ALS onset in patients with DM was 4.2 years later (95% confidence interval 1.3-7.2 years) than in patients without DM (P < 0.01). The overall survival of patients with high body mass index at study entry (>27.0 kg/m² , upper quartile, n = 127) was prolonged by more than 5 months compared to patients with low body mass index (<22.0 kg/m² , lower quartile, n = 123; P = 0.04).

CONCLUSIONS

This study supports the view that statin use is not associated with overall survival of ALS patients, suggesting that statins are not harmful and should not be discontinued in ALS. Furthermore, the delayed onset of ALS in patients with DM may mirror the potentially protective metabolic profile associated with type 2 DM. Consistently, this study provides further evidence that high body mass index is a positive prognostic factor in ALS.

Antidiabetics, statins and the risk of amyotrophic lateral sclerosis

BACKGROUND

Medications that are used for treatment of metabolic disorders have been suggested to be associated with the development of amyotrophic lateral sclerosis (ALS).

METHODS

To examine the associations of antidiabetics and statins with the subsequent risk of ALS we conducted a population-based nested case-control study of 2475 Swedish residents diagnosed with ALS during July 2006 to December 2013 and 12 375 population controls (five for each ALS case). We extracted information on filled prescriptions of antidiabetics and statins for both cases and controls from the Swedish Prescribed Drug Register during the years before ALS diagnosis. Conditional logistic regression was used to calculate odds ratios (ORs) for the associations of these medications with ALS risk.

RESULTS

Patients with ALS were less likely to have been prescribed with antidiabetics compared with controls [OR, 0.76; 95% confidence intervals (CI), 0.65-0.90]. Conversely, statins were not associated with ALS risk overall (OR, 1.08; 95% CI, 0.98-1.19), although a positive association was noted among women (OR, 1.28; 95% CI, 1.10-1.48). The latter association was mostly explained by ALS cases being more likely to have a first prescription of statins during the year before diagnosis compared with controls (OR, 2.54; 95% CI, 1.84-3.49).

CONCLUSIONS

The inverse association of antidiabetics with ALS is consistent with the previously reported inverse association between type 2 diabetes and ALS risk. The increase in prescription of statins during the year before ALS diagnosis deserves attention because it might reflect an acceleration of the course of ALS due to statin use.

Plasma creatinine and oxidative stress biomarkers in amyotrophic lateral sclerosis

Objective: To determine the associations between plasma creatinine (PCr), plasma uric acid (PUA), and urinary oxidative stress (OS) biomarkers with the ALSFRS-R at baseline and survival in a large epidemiological cohort study (ALS COSMOS) with a well-phenotyped patient population (N = 355).Methods: Fasting plasma and first void urine samples were obtained. PCr, PUA, urinary 8-oxo-deoxy guanosine (8-oxodG), and 15-F_2t-isoprostane (IsoP) were analyzed at baseline, near the midpoint of follow-up, and at the final blood draw (before death or withdrawal from study). We estimated associations between these biomarkers and the ALSFRS-R at baseline and survival.Results: At baseline, PCr correlated with ALSFRS-R (Spearman r = 0.30), percent (%) FVC (r = 0.20), PUA (r = 0.37), and 8-oxodG (r = -0.13, all p < 0.05). Baseline PCr significantly predicted survival (adjusted hazard ratio 0.28, p < 0.001). Time to death from baseline was shortest for those in the lowest two PCr quartiles relative to the highest two quartiles. PCr and ALSFRS-R values were significantly correlated at all three time points (baseline: r = 0.29, midpoint: r = 0.23, final: r = 0.38, all p < 0.001). PCr and PUA significantly declined over time, whereas OS biomarkers significantly increased over time.Conclusions: To date, PCr predicted survival the best, compared to PUA, 8-oxodG, and IsoP. Although PCr represents the degree of muscle mass, it may also represent complex biochemical changes in ALS. Because the field has no reliable prognostic biomarkers, the importance of PCr warrants further investigation through clinical studies in ALS.

Lipids, apolipoproteins, and prognosis of amyotrophic lateral sclerosis

OBJECTIVE

To determine whether lipids and apolipoproteins predict prognosis of patients with amyotrophic lateral sclerosis in a cohort study of 99 patients with amyotrophic lateral sclerosis who were diagnosed during 2015 to 2018 and followed up until October 31, 2018, at the Neurology Clinic in Karolinska University Hospital in Stockholm, Sweden.

METHODS

Total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoprotein AI, apolipoprotein B, and lipid ratios were measured at the time of amyotrophic lateral sclerosis diagnosis or shortly thereafter. Death after amyotrophic lateral sclerosis diagnosis was used as the main outcome. The Cox model was used to estimate hazard ratios with 95% confidence intervals of death after amyotrophic lateral sclerosis diagnosis, after controlling for sex, age at diagnosis, site of symptom onset, diagnostic delay, body mass index, Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised score, and progression rate.

RESULTS

A 1-SD increase of total cholesterol (hazard ratio 0.60, 95% confidence interval 0.41-0.89, p = 0.01), low-density lipoprotein cholesterol (hazard ratio 0.64, 95% confidence interval 0.44-0.92, p = 0.02), low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (hazard ratio 0.65, 95% confidence interval 0.46-0.92, p = 0.02), apolipoprotein B (hazard ratio 0.62, 95% confidence interval 0.44-0.88, p = 0.01), or apolipoprotein B/apolipoprotein AI ratio (hazard ratio 0.61, 95% confidence interval 0.43-0.86, p < 0.01) was associated with a lower risk of death after amyotrophic lateral sclerosis diagnosis. A dose-response relationship was also noted when these biomarkers were analyzed as categorical variables.

CONCLUSIONS

Lipids and apolipoproteins are important prognostic indicators for amyotrophic lateral sclerosis and should be monitored at the diagnosis of amyotrophic lateral sclerosis.

Prediagnostic plasma polyunsaturated fatty acids and the risk of amyotrophic lateral sclerosis

OBJECTIVE

To examine the association between prediagnostic plasma polyunsaturated fatty acids levels (PUFA) and amyotrophic lateral sclerosis (ALS).

METHODS

We identified 275 individuals who developed ALS while enrolled in 5 US prospective cohorts, and randomly selected 2 controls, alive at the time of the case diagnosis, matched on cohort, birth year, sex, ethnicity, fasting status, and time of blood draw. We measured PUFA, expressed as percentages of total fatty acids, using gas liquid chromatography and used conditional logistic regression to estimate risk ratios (RR) and 95% confidence intervals (CI) for the association between PUFA and ALS.

RESULTS

There was no association between total, n-3, and n-6 PUFA, eicosapentaenoic acid, or docosapentaenoic acid levels and ALS. Higher plasma α-linolenic acid (ALA) in men was associated with lower risk of ALS in age- and matching factor-adjusted analyses (top vs bottom quartile: RR = 0.21 [95% CI 0.07, 0.58], p for trend = 0.004). In women, higher plasma arachidonic acid was associated with higher risk (top vs bottom quartile: RR = 1.65 [95% CI 0.99, 2.76], p for trend = 0.052). Multivariable adjustment, including correlated PUFA, did not change the findings for ALA and arachidonic acid. In men and women combined, higher plasma docosahexaenoic acid (DHA) was associated with higher risk of ALS (top vs bottom quartile: RR = 1.56 [95% CI 1.01, 2.41], p for trend = 0.054), but in multivariable models the association was only evident in men.

CONCLUSIONS

The majority of individual PUFAs were not associated with ALS. In men, ALA was inversely and DHA was positively related to risk of ALS, while in women arachidonic acid was positively related. These findings warrant confirmation in future studies.

Peripheral immune biomarkers and neurodegenerative diseases: A prospective cohort study with 20 years of follow-up

OBJECTIVE

To assess the associations of several blood immune biomarkers with the future risks of amyotrophic lateral sclerosis and Parkinson disease in a prospective cohort study with 20 years of follow-up.

METHODS

The Swedish Apolipoprotein-Related Mortality Risk study is a longitudinal cohort study including 812,073 participants with repeated blood biomarker measurements between 1985 and 1996 and a follow-up until 2011. Using a Cox model, we first estimated hazard ratios of amyotrophic lateral sclerosis and Parkinson disease in relation to leukocytes, immunoglobulin G, haptoglobin, and uric acid. We further described the temporal changes of these biomarkers during the 20 years prior to the diagnosis of these diseases.

RESULTS

A total of 585 incident cases of amyotrophic lateral sclerosis and 3,769 incident cases of Parkinson disease were identified during the follow-up. Increasing concentrations of leukocytes, haptoglobin, and uric acid were associated with a lower risk of Parkinson disease. No statistically significant association was, however, noted between the studied biomarkers and amyotrophic lateral sclerosis. Parkinson disease patients appeared to have lower levels of leukocytes and haptoglobin between 20 and 10 years before diagnosis and lower levels of uric acid during the 20 years before diagnosis, compared to controls, although statistically significant differences were only noted during parts of the respective time intervals after multivariable adjustment. No clear differences were noted between patients with amyotrophic lateral sclerosis and controls.

INTERPRETATION

If verified in studies of independent populations, our findings may suggest a different role of systemic inflammation on the risk of Parkinson disease compared to amyotrophic lateral sclerosis. ANN NEUROL 2019;86:913-926.

Metabolic Alteration and Amyotrophic Lateral Sclerosis Outcome: A Systematic Review

Background: The development of strategies that could not only efficiently detect the onset of Amyotrophic Lateral Sclerosis (ALS), a fatal neurodegenerative disorder with no cure but also predict its development and evaluate therapeutic intervention would be of great value. In this respect, the metabolic status of ALS patients has called attention. Hence, this study aimed to investigate the potential correlation between changes in ALS's metabolic parameters with the disease outcome in a systematic review. Methods: The manuscripts were manually searched within different databases (PubMed, Web of Science and Cochrane). The inclusion criteria were original articles and reviews about individuals with ALS and its survival, disease prognosis and metabolism (weight, cholesterol, hypertension, BMI, and glycaemia). The authors also established three different exclusion criteria: studies including ALS and other degenerative disorders, works including animal models and published before the year 2000. Results: In total, 29 papers were selected. From all manuscripts, only 82.8% ensured the participation of sALS patients. Also, 27.6% of selected studies described the presence of a genetic mutation. Regarding ALS prognosis, patient's age, the age of ALS onset, ALS duration and survival, <50% of the papers addressed these issues. Specifically, regarding metabolism, 65.5% of articles mentioned BMI, 20.7% mentioned any data concerning hypertension, 6.89% cardiovascular risk, 10.3% obesity, 13.78% diabetes and 10.3% glycaemia. Concerning lipid metabolism, more results were gathered, but still, they did not suffice to establish a correlation with ALS development. Conclusions: Altogether, the authors concluded that available information is not enough to establish a link between ALS and metabolism. In reality, less than half of the manuscripts evaluated show an association between both factors. Nonetheless, it is worth mentioning that metabolism does influence ALS, but not in a unique manner. There is a debate about patients' hypo- and hypermetabolism. Thus, to provide a reliable record, a public policy in which all research and clinical centers might assess the parameters discussed herein is suggested. Accordingly, this systematic review attempts to provide a comprehensible database to facilitate multicentered collaboration, validation, and clinical translation.

Elevated serum creatine kinase in the early stage of sporadic amyotrophic lateral sclerosis

OBJECTIVE

To assess the changes of muscle-related biomarkers at the early stage of amyotrophic lateral sclerosis, and to confirm these findings in an experimental animal model.

METHODS

Thirty-nine subjects with sporadic amyotrophic lateral sclerosis and 20 healthy controls were enrolled and longitudinally evaluated. We evaluated serum creatine kinase and creatinine levels and appendicular lean soft-tissue mass using dual X-ray absorptiometry. The levels of biomarkers at early ALS stages were estimated using linear mixed models with unstructured correlation and random intercepts. We also analyzed the longitudinal changes of serum creatine kinase and creatinine, together with the mRNA levels of acetylcholine receptor subunit γ (Chrng) and muscle-associated receptor tyrosine kinase, markers of denervation, in the gastrocnemius muscle of superoxide dismutase 1 (SOD1)^G93A transgenic mice, an animal model of amyotrophic lateral sclerosis.

RESULTS

The estimated levels of creatine kinase were higher in subjects with amyotrophic lateral sclerosis at the early stage than in healthy controls, although the estimated appendicular lean soft-tissue mass and creatinine levels were equivalent between both groups, suggesting that the elevation of creatine kinase precedes both muscular atrophy and subjective motor symptoms in sporadic amyotrophic lateral sclerosis. In SOD1^G93A mice, the serum levels of creatine kinase were elevated at 9 weeks of age (peri-onset) when Chrng started to be up-regulated, and were then down-regulated at 15 weeks of age, consistent with the clinical data from patients with sporadic amyotrophic lateral sclerosis.

INTERPRETATION

Creatine kinase elevation precedes muscular atrophy and reflects muscle denervation at the early stage.

Lipids, Apolipoproteins, and the Risk of Parkinson Disease

RATIONALE

A complete picture of the associations of the most common lipid fractions, including total cholesterol (TC), LDL-C (low-density lipoprotein cholesterol), HDL-C (high-density lipoprotein cholesterol), triglycerides, and apolipoproteins, with the risk of Parkinson disease (PD), is lacking.

OBJECTIVE

To assess the associations of lipids and apolipoproteins with the future risk of PD.

METHODS AND RESULTS

In the AMORIS (Apolipoprotein-Related Mortality Risk) Study, we enrolled ≈600 000 participants during 1985 to 1996 in Stockholm, Sweden, with repeated measurements of TC, LDL-C, HDL-C, triglycerides, ApoB (apolipoprotein B), and ApoA-I (apolipoprotein A-I). The cohort was followed until the end of 2011, and incident cases of PD were identified through the Swedish Patient Register. We first used Cox models to estimate the associations of these biomarkers with later risk of PD. We further applied a Mendelian randomization analysis for TC, LDL-C, and triglycerides using the GWAS (Genome-wide association study) summary statistics from the public PD GWAS data and 23andMe PD cohorts with >800 000 individuals. One SD increase of TC was associated with a lower hazard of PD (hazard ratio, 0.90; 95% CI, 0.87-0.94). Similar associations were observed for LDL-C (hazard ratio, 0.93; 95% CI, 0.88-0.98), triglycerides (hazard ratio, 0.94; 95% CI, 0.90-0.97), and ApoB (hazard ratio, 0.91; 95% CI, 0.85-0.97). A clear dose-response relation was also noted when using these biomarkers as categorical variables. A causal inverse association of TC, LDL-C, and triglycerides with PD risk was further suggested by the Mendelian randomization analysis.

CONCLUSIONS

Our findings reinforce that higher levels of TC, LDL-C, and triglycerides are associated with a lower future risk of PD and further suggest that these associations may be causal. The findings for ApoB in relation to PD risk are novel, and whether such association is causal needs to be examined.

Type II diabetes mellitus and the incidence of amyotrophic lateral sclerosis

OBJECTIVE

The aim of this study was to investigate the relationship between type II diabetes mellitus (T2DM) and ALS incidence using the National Health Insurance Research Database and Serious Disabling Disease database of Taiwan.

METHODS

This was a population-based cohort study. The index date was the date of the first T2DM diagnosis + 365 days. We included T2DM patients diagnosis between 2000 and 2013 (n = 2,135,427). These patients were matched by sex, age, urbanization, and insurance premium at a ratio of 1:1 to include patients without diabetes mellitus. Competing risk-adjusted Cox regression analysis was performed to investigate the association between T2DM and the incidence of ALS.

RESULTS

In the patients not stratified by age, T2DM was not associated with the incidence of ALS after controlling for confounding factors. The interaction test of age subgroup (< 55 and ≥ 55 years) and T2DM on ALS risk was significance (p < 0.001). Subgroup analysis showed that T2DM was negatively associated with ALS in patients whose age at the first T2DM diagnosis was ≥ 55 years. Among T2DM patients, T2DM combined with hypertension was negatively associated with ALS among patients whose age at the first T2DM diagnosis was ≥ 55 years. Among T2DM patients, T2DM combined with hyperlipidemia was positively associated with ALS among patients whose age at the first T2DM diagnosis was < 55 years.

CONCLUSIONS

The late-onset of T2DM may exert negative association with ALS, especially when combined with hypertension. The early-onset of T2DM may exert positive association with ALS, especially when combined with hyperlipidemia.

Lipid Biomarkers for Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal degenerative disease primarily characterized by the selective loss of upper and lower motor neurons. To date, there is still an unmet need for robust and practical biomarkers that could estimate the risk of the disease and its progression. Based on metabolic modifications observed at the level of the whole body, different classes of lipids have been proposed as potential biomarkers. This review summarizes investigations carried out over the last decade that focused on changes in three major lipid species, namely cholesterol, triglycerides and fatty acids. Despite some contradictory findings, it is becoming increasingly accepted that dyslipidemia, and related aberrant energy homeostasis, must be considered as essential components of the pathological process. Therefore, it is tempting to envisage dietary interventions as a means to counterbalance the metabolic disturbances and ameliorate the patient's quality of life.

Biomarkers in Motor Neuron Disease: A State of the Art Review

Motor neuron disease can be viewed as an umbrella term describing a heterogeneous group of conditions, all of which are relentlessly progressive and ultimately fatal. The average life expectancy is 2 years, but with a broad range of months to decades. Biomarker research deepens disease understanding through exploration of pathophysiological mechanisms which, in turn, highlights targets for novel therapies. It also allows differentiation of the disease population into sub-groups, which serves two general purposes: (a) provides clinicians with information to better guide their patients in terms of disease progression, and (b) guides clinical trial design so that an intervention may be shown to be effective if population variation is controlled for. Biomarkers also have the potential to provide monitoring during clinical trials to ensure target engagement. This review highlights biomarkers that have emerged from the fields of systemic measurements including biochemistry (blood, cerebrospinal fluid, and urine analysis); imaging and electrophysiology, and gives examples of how a combinatorial approach may yield the best results. We emphasize the importance of systematic sample collection and analysis, and the need to correlate biomarker findings with detailed phenotype and genotype data.

Defining pre-symptomatic amyotrophic lateral sclerosis

Successful treatment of neurodegenerative disease may hinge on early therapeutic intervention. This requires an understanding of early/pre-symptomatic disease, a need that is underscored by advances in antisense oligonucleotide, and viral-vector-based gene therapies. In amyotrophic lateral sclerosis (ALS), the study of pre-symptomatic disease requires a cohesive conceptual framework for describing this phase of disease. Informed by the literature in other neurodegenerative diseases and extensive personal experience, a model is proposed that distinguishes ALS as a clinical syndrome from ALS as a disease, and characterizes pre-symptomatic ALS as having two identifiable stages: pre-manifest and prodromal. The unique and critical importance of biomarker development is articulated and an operational definition of phenoconversion is provided. It is hoped that this framework will accelerate collective efforts to study pre-symptomatic ALS, and aid in the design and implementation of an early intervention- or disease-prevention trial.

Biomarkers of Metabolism in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the deterioration of motor neurons. However, this complex disease extends beyond the boundaries of the central nervous system, with metabolic alterations being observed at the systemic and cellular level. While the number of studies that assess the role and impact of metabolic perturbations in ALS is rapidly increasing, the use of metabolism biomarkers in ALS remains largely underinvestigated. In this review, we discuss current and potential metabolism biomarkers in the context of ALS. Of those for which data does exist, there is limited insight provided by individual markers, with specificity for disease, and lack of reproducibility and efficacy in informing prognosis being the largest drawbacks. However, given the array of metabolic markers available, the potential exists for a panel of metabolism biomarkers, which may complement other current biomarkers (including neurophysiology, imaging, as well as CSF, blood and urine markers) to overturn these limitations and give rise to new diagnostic and prognostic indicators.

Shared polygenic risk and causal inferences in amyotrophic lateral sclerosis

OBJECTIVE

To identify shared polygenic risk and causal associations in amyotrophic lateral sclerosis (ALS).

METHODS

Linkage disequilibrium score regression and Mendelian randomization were applied in a large-scale, data-driven manner to explore genetic correlations and causal relationships between >700 phenotypic traits and ALS. Exposures consisted of publicly available genome-wide association studies (GWASes) summary statistics from MR Base and LD-hub. The outcome data came from the recently published ALS GWAS involving 20,806 cases and 59,804 controls. Multivariate analyses, genetic risk profiling, and Bayesian colocalization analyses were also performed.

RESULTS

We have shown, by linkage disequilibrium score regression, that ALS shares polygenic risk genetic factors with a number of traits and conditions, including positive correlations with smoking status and moderate levels of physical activity, and negative correlations with higher cognitive performance, higher educational attainment, and light levels of physical activity. Using Mendelian randomization, we found evidence that hyperlipidemia is a causal risk factor for ALS and localized putative functional signals within loci of interest.

INTERPRETATION

Here, we have developed a public resource (https://lng-nia.shinyapps.io/mrshiny) which we hope will become a valuable tool for the ALS community, and that will be expanded and updated as new data become available. Shared polygenic risk exists between ALS and educational attainment, physical activity, smoking, and tenseness/restlessness. We also found evidence that elevated low-desnity lipoprotein cholesterol is a causal risk factor for ALS. Future randomized controlled trials should be considered as a proof of causality. Ann Neurol 2019;85:470-481.

Clinical disease stage related changes of serological factors in amyotrophic lateral sclerosis

OBJECTIVE

Little is known whether disease clinical stage would influence the serological values in Amyotrophic lateral sclerosis (ALS). We aimed to explore the association between the levels of serological factors with clinical progression determined by the King's College staging system.

METHODS

ALS Patients were registered from May 2008 to December 2016. The differences of serological values between patients and healthy controls, and the correlation of these serological values with disease stage were examined.

RESULTS

A total of 571 patients and 571 age-/gender-/BMI-matched healthy controls were included. The levels of creatinine, uric acid (UA), albumin, total protein, total cholesterol, and high-density lipoprotein (HDL) were significantly lower, and the low-density lipoprotein/HDL ratio was higher in ALS patients than those in healthy controls. The levels of UA, albumin, and total protein were significantly reversely correlated with diseases stages. The longitudinal observation of 81 ALS patients also showed that the levels of UA, creatinine, albumin, total protein, and HDL were significantly decreased in the second hematological examinations.

CONCLUSIONS

In the present study, ALS patients and control subjects were evenly matched with regard to sex, age, and BMI value, this finding could be considered as a metabolite signature in ALS. The changes of metabolite-based serological factors with progression of disease stage might be related to the pathophysiology of disease, and might have clinical utility in clinical practice.

[A prognostic biomarker in amyotrophic lateral sclerosis]

Although we currently have two, approved, disease-modifying drugs for the treatment of amyotrophic lateral sclerosis (ALS), we are in disperate need for more efficacious treatment. To aggressively test for newer therapies, we must develop reliable objective biomarkers to supplement clinical outcome measures. Many biomarker candidates have been actively and vigorously investigated. Among neurophysiological biomarkers, transcranial magnetic stimulation (TMS)-based biomarkers show potential in exploring disease mechanisms. Neuroimaging biomarkers have high specificity in diagnosing ALS but are an expensive endeavor and are not sensitive enough to detect changes over time of the disease. Among fluid-based biochemical biomarkers, creatinine (Crn) and uric acids (UA), which have been known for decades, may prove to be highly promising biomarkers that can predict disease progression. They can be easily tested in any clinical trials because the costs are minimal. Although known for some time, neurofilaments (NF), either phosphorylated-NF heavy subunit (pNFH) or NF light subunit (NFL), have emerged as "new" biomarkers using specific antibodies. They appear to be highly specific and sensitive in diagnosing ALS, yet they may be insensitive to assess changes in disease over time. These two NF biomarkers along with Crn and UA should be explored extensively in future clinical trials and any other clinical studies in ALS. Yet, we still need newer, more innovative, and reliable biomarkers for future ALS research. Fortunatley, aggressive investigations appear to be currently underway.

Preclinical progression of neurodegenerative diseases

Neurodegenerative diseases are disorders that are characterized by a progressive decline of the motor and/or cognitive function caused by a selective loss of neurons within the central nervous system. Recent advancements in the translational research have facilitated extensive insights into the molecular pathophysiology of neurodegenerative diseases. Nonetheless, a myriad of compounds that suppressed the disease progression in cellular and animal models did not exhibit efficacy in clinical trials. Perhaps, various biological, medical, and methodological factors could be attributed to unfavorable results of clinical trials of such disease-modifying therapies. Primarily, the fact that pathological changes at molecular and cellular levels precede the clinical onset by several years underscores a pressing need for the initiation of interventions before the emergence of neurological symptoms. Using exquisite biomarkers, recent studies revealed the preclinical and prodromal progression of pathophysiology, as well as compensatory brain responses in several neurodegenerative diseases. This review aims to discuss the recent advancement of biomarker studies on presymptomatic subjects and the perspective on a preventive trial of disease-modifying therapies for devastating neurological disorders.

Profile of Arachidonic Acid-Derived Inflammatory Markers and Its Modulation by Nitro-Oleic Acid in an Inherited Model of Amyotrophic Lateral Sclerosis

The lack of current treatments for amyotrophic lateral sclerosis (ALS) highlights the need of a comprehensive understanding of the biological mechanisms of the disease. A consistent neuropathological feature of ALS is the extensive inflammation around motor neurons and axonal degeneration, evidenced by accumulation of reactive astrocytes and activated microglia. Final products of inflammatory processes may be detected as a screening tool to identify treatment response. Herein, we focus on (a) detection of arachidonic acid (AA) metabolization products by lipoxygenase (LOX) and prostaglandin endoperoxide H synthase in SOD1^G93A mice and (b) evaluate its response to the electrophilic nitro-oleic acid (NO₂-OA). Regarding LOX-derived products, a significant increase in 12-hydroxyeicosatetraenoic acid (12-HETE) levels was detected in SOD1^G93A mice both in plasma and brain whereas no changes were observed in age-matched non-Tg mice at the onset of motor symptoms (90 days-old). In addition, 15-hydroxyeicosatetraenoic acid (15-HETE) levels were greater in SOD1^G93A brains compared to non-Tg. Prostaglandin levels were also increased at day 90 in plasma from SOD1^G93A compared to non-Tg being similar in both types of animals at later stages of the disease. Administration of NO₂-OA 16 mg/kg, subcutaneously (s/c) three times a week to SOD1^G93A female mice, lowered the observed increase in brain 12-HETE levels compared to the non-nitrated fatty acid condition, and modified many others inflammatory markers. In addition, NO₂-OA significantly improved grip strength and rotarod performance compared to vehicle or OA treated animals. These beneficial effects were associated with increased hemeoxygenase 1 (HO-1) expression in the spinal cord of treated mice co-localized with reactive astrocytes. Furthermore, significant levels of NO₂-OA were detected in brain and spinal cord from NO₂-OA -treated mice indicating that nitro-fatty acids (NFA) cross brain–blood barrier and reach the central nervous system to induce neuroprotective actions. In summary, we demonstrate that LOX-derived oxidation products correlate with disease progression. Overall, we are proposing that key inflammatory mediators of AA-derived pathways may be useful as novel footprints of ALS onset and progression as well as NO₂-OA as a promising therapeutic compound.

Combined measurement of plasma cystatin C and low-density lipoprotein cholesterol: A valuable tool for evaluating progressive supranuclear palsy

INTRODUCTION

Progressive supranuclear palsy (PSP) was previously thought as a cause of atypical Parkinsonism. Although Cystatin C (Cys C) and low-density cholesterol lipoprotein-C (LDL-C) are known to play critical roles in Parkinsonism, it is unknown whether they can be used as markers to distinguish PSP patients from healthy subjects and to determine disease severity.

METHODS

We conducted a cross-sectional study to determine plasma Cys C/HDL/LDL-C levels of 40 patients with PSP and 40 healthy age-matched controls. An extended battery of motor and neuropsychological tests, including the PSP-Rating Scale (PSPRS), the Non-Motor Symptoms Scale (NMSS), Geriatric Depression Scale (GDS) and Mini-Mental State Examination (MMSE), was used to evaluate the disease severity. Receiver operating characteristic (ROC) curves were adopted to assess the prognostic accuracy of Cys C/LDL-C levels in distinguishing PSP from healthy subjects.

RESULTS

Patients with PSP exhibited significantly higher plasma levels of Cys C and lower LDL-C. The levels of plasma Cys C were positively and inversely correlated with the PSPRS/NMSS and MMSE scores, respectively. The LDL-C/HDL-C ratio was positively associated with PSPRS/NMSS and GDS scores. The ROC curve for the combination of Cys C and LDL-C yielded a better accuracy for distinguishing PSP from healthy subjects than the separate curves for each parameter.

CONCLUSIONS

Plasma Cys C and LDL-C may be valuable screening tools for differentiating PSP from healthy subjects; while they could be useful for the PSP intensifies and severity evaluation. A better understanding of Cys C and LDL-C may yield insights into the pathogenesis of PSP.

Biomarkers of Amyotrophic Lateral Sclerosis: Current Status and Interest of Oxysterols and Phytosterols

Amyotrophic lateral sclerosis (ALS) is a non-demyelinating neurodegenerative disease in adults with motor disorders. Two forms exist: a sporadic form (90% of cases) and a family form due to mutations in more than 20 genes including the Superoxide dismutase 1, TAR DNA Binding Protein, Fused in Sarcoma, chromosome 9 open reading frame 72 and VAPB genes. The mechanisms associated with this pathology are beginning to be known: oxidative stress, glutamate excitotoxicity, protein aggregation, reticulum endoplasmic stress, neuroinflammation, alteration of RNA metabolism. In various neurodegenerative diseases, such as Alzheimer's disease or multiple sclerosis, the involvement of lipids is increasingly suggested based on lipid metabolism modifications. With regard to ALS, research has also focused on the possible involvement of lipids. Lipid involvement was suggested for clinical arguments where changes in cholesterol and LDL/HDL levels were reported with, however, differences in positivity between studies. Since lipids are involved in the membrane structure and certain signaling pathways, it may be considered to look for oxysterols, mainly 25-hydroxycholesterol and its metabolites involved in immune response, or phytosterols to find suitable biomarkers for this pathology.