Disease Progression In Amyotrophic Lateral Sclerosis Patients Research Articles

Exploring the Role of Metabolic Hormones in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by progressive loss of motor neurons. Emerging evidence suggests a potential link between metabolic dysregulation and ALS pathogenesis. This study aimed to investigate the relationship between metabolic hormones and disease progression in ALS patients. A cross-sectional study was conducted involving 44 ALS patients recruited from a tertiary care center. Serum levels of insulin, total amylin, C-peptide, active ghrelin, GIP (gastric inhibitory peptide), GLP-1 active (glucagon-like peptide-1), glucagon, PYY (peptide YY), PP (pancreatic polypeptide), leptin, interleukin-6, MCP-1 (monocyte chemoattractant protein-1), and TNFα (tumor necrosis factor alpha) were measured, and correlations with ALSFRS-R, evolution scores, and biomarkers were analyzed using Spearman correlation coefficients. Subgroup analyses based on ALS subtypes, progression pattern of disease, and disease progression rate patterns were performed. Significant correlations were observed between metabolic hormones and ALS evolution scores. Insulin and amylin exhibited strong correlations with disease progression and clinical functional outcomes, with insulin showing particularly robust associations. Other hormones such as C-peptide, leptin, and GLP-1 also showed correlations with ALS progression and functional status. Subgroup analyses revealed differences in hormone levels based on sex and disease evolution patterns, with male patients showing higher amylin and glucagon levels. ALS patients with slower disease progression exhibited elevated levels of amylin and insulin. Our findings suggest a potential role for metabolic hormones in modulating ALS progression and functional outcomes. Further research is needed to elucidate the underlying mechanisms and explore the therapeutic implications of targeting metabolic pathways in ALS management.

P.222 Wearable inertial sensors for longitudinal follow-up of patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the loss of motor neuron leading to weakness and death often resulting from failure of the respiratory muscles. There have been numerous recent discoveries in ALS research leading to potential therapies that will need testing in clinical trials. Due to outcome measures limitations, trials, especially for neurodegenerative disorders, require large sample sizes, long durations and have a high risk for failure. Digital biomarkers collected with wearable devices could provide powerful outcome measures through an objective assessment performed in real-life. Remote continuous monitoring is an innovative method for quantifying disease progression in ALS patients providing for motor function assessment through patients' loss of ambulation. This opportunity for shorter and less burdensome clinical trials should be confirmed by further data collection. We designed a longitudinal natural history study in ALS. Participants were assessed with standard evaluations including the amyotrophic lateral sclerosis functional rating scale, six-minute walk test, Medical Research Council scores, Ashworth score, hand dynamometer, pulmonary function and cognitive tests every 3 months for 1 year. After each visit, patients were asked to wear for one month one inertial sensor at the ankle and one at the wrist for continuous assessment of motor function in real-life. These data will be compared with already acquired normative data. At the present time, 11 patients with ALS (3 females, 8 males) aged from 44 to 72 years old were included. Four patients discontinued the study due to death or permanent ventilation. Initial results suggest that upper and lower limb variables are lower in patient with ALS than in controls and show a downward trend over time. We will present longitudinal data along with correlation between change in traditional and digital outcome measures. We will show comparison between patients and controls.

MOLECULAR DOCKING STUDIES OF MONOMERIC WILDTYPE AND MUTANT (H81A, H49R) SOD1 WITH EDARAVONE AND RILUZOLE

Objective: Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder that causes progressive loss of the upper and lower motor neurons in the brain and spinal cord. SOD1 was the first gene linked to ALS, in which more than 150 mutations throughout the sequence of the protein have been found to be associated with ALS. Methods: The drugs that can interact and inhibit the misfolding or revert the misconformation of the protein can be useful in the treatment of ALS. Monomer apo SOD1-WT and MBR SOD1 mutants (H81A, H49R) were docked with the only two FDA-approved drugs for ALS that are edaravone and riluzole to assess if the ALS patients carrying these particular protein aggregates will derive any therapeutic efficacy. Results: The drugs were found to interact with both wild-type and mutant SOD1 at different positions and the type of interaction, degree of interaction and their binding energies were determined. SOD1-WT has hydrophobic interactions at V103, H110, and R115 and hydrogen bond at H110 with edaravone. SOD1-WT has hydrophobic interactions at T54, F64 and hydrogen bond at D52, T58 with riluzole. Both SOD1 mutants has a hydrogen bond at its H46 residue for both drugs. SOD1-H49R mutant has hydrophobic interactions at F45 with riluzole. SOD1-H81A mutant has hydrophobic interactions at F45 with edaravone. Conclusion: Both the mutants L42A residue has a hydrophobic interaction with edaravone. Interaction of drugs with protein and its mutants may make it possible to restore the stability of SOD1 structure and attenuate disease progression in ALS patients carrying these mutations.

Fertility Does Not Alter Disease Progression in ALS Patients of Childbearing Age: A Three Centers Retrospective Analysis in Southern China.

BackgroundLimited data exists on the clinical features of patients with amyotrophic lateral sclerosis (ALS) during reproductive ages.ObjectiveOur study characterized the clinical features of ALS and the effects of pregnancy on disease progression in patients with ALS.MethodsWe performed a retrospective study of female patients with ALS in three ALS research centers in southern China from 2009 to 2021. Data regarding fertility status, and clinical and genetic features, were collected. Age-matched male patients with ALS served as controls. The patients were divided into the following two subgroups: patients with symptom onset within 1 year of pregnancy and patients with symptom onset over 1 year group after pregnancy.ResultsA total of 52 female and 52 matched male patients were enrolled. There were no differences in female and male patients in the mean age of symptom onset, the mean baseline ALSFRS-R score, or median reduction of ALSFRS-R score (p > 0.05). The mean age of first pregnancy was 25.57 ± 4.40) years. The mean age of first pregnancy in the over 1 year group was lower than that in the within 1 year group (p= 0.01). There was no difference in the median reduction of ALSFRS-R between the two subgroups. In the univariate analysis, diagnostic delay was highly correlated with the disease progression, with short delay representing rapid progress. No multicollinearity was found among every variable. In addition, 40.38% patients carried ALS-related gene variants. The proportion with gene mutations in the within 1 year group was higher than that in the over 1 year group (p < 0.01). Furthermore, SETX was the most frequently mutated gene in this cohort (16.67%) including 4 uncertain mutation.ConclusionPregnancy and fertility were not associated with disease progression. Diagnostic delay was correlated with disease progression in this cohort. In addition, SETX might be a gene of concern for ALS patients of childbearing age.

Serum uric acid level predicts the progression of amyotrophic lateral sclerosis following treatment with edaravone

ABSTRACT Introduction Uric acid and edaravone might exert a neuroprotective effect in amyotrophic lateral sclerosis (ALS) by reducing oxidative stress. We analyzed whether the treatment effect of edaravone is pronounced in patients whose uric acid level increased after the treatment with edaravone. Materials and methods Forty patients with ALS who underwent treatment with edaravone were included. Baseline uric acid level and the rate of decline in uric acid after edaravone treatment were recorded. The rate of change of ALS functional rating scale-revised (ΔALSFRS-R/month) was calculated based on baseline ALSFRS-R score and ALSFRS-R score 6–24 weeks after the treatment. Results The serum uric acid levels decreased after treatment in 26 (65%) patients and increased in 12 (30%) patients. The ΔALSFRS-R/month was significantly faster in patients whose uric acid decreased (median 1.5 [Q1–Q3, 0.7–3.1]) than in patients whose uric acid increased (0.2 [0–1.0], p = 0.021). A high baseline uric acid level and low rate of decline in uric acid was associated with slower disease progression after adjusting for age, initial symptoms, and riluzole administration (p = 0.030 and p = 0.041, respectively). Discussion High baseline values and low rate of decline in uric acid may predict slow disease progression in ALS patients treated with edaravone.

Targeting the epigenome to treat neurodegenerative diseases or delay their onset: a perspective

Targeting the epigenome to treat neurodegenerative diseases or delay their onset: a perspective

Advancing disease monitoring of amyotrophic lateral sclerosis with the compound muscle action potential scan

ObjectiveTo determine which compound muscle action potential (CMAP) scan-derived electrophysiological markers are most sensitive for monitoring disease progression in amyotrophic lateral sclerosis (ALS), and whether they hold value for clinical trials. MethodsWe used four independent patient cohorts to assess longitudinal patterns of a comprehensive set of electrophysiological markers including their association with the ALS functional rating scale (ALSFRS-R). Results were translated to trial sample size requirements. ResultsIn 65 patients, 225 thenar CMAP scan recordings were obtained. Electrophysiological markers showed extensive variation in their longitudinal trajectories. Expressed as standard deviations per month, motor unit number estimation (MUNE) values declined by 0.09 (CI 0.07–0.12), D50, a measure that quantifies CMAP scan discontinuities, declined by 0.09 (CI 0.06–0.13) and maximum CMAP by 0.05 (CI 0.03–0.08). ALSFRS-R declined fastest (0.12, CI 0.08 – 0.15), however the between-patient variability was larger compared to electrophysiological markers, resulting in larger sample sizes. MUNE reduced the sample size by 19.1% (n = 388 vs n = 314) for a 6-month study compared to the ALSFRS-R. ConclusionsCMAP scan-derived markers show promise in monitoring disease progression in ALS patients, where MUNE may be its most suitable derivate. SignificanceMUNE may increase clinical trial efficiency compared to clinical endpoints.

Pathogenic or protective? Neuropeptide Y in amyotrophic lateral sclerosis.

Neuropeptide Y (NPY) is an endogenous peptide of the central and enteric nervous systems which has gained significant interest as a potential neuroprotective agent for treatment of neurodegenerative disease. Amyotrophic lateral sclerosis (ALS) is an aggressive and fatal neurodegenerative disease characterized by motor deficits and motor neuron loss. In ALS, recent evidence from ALS patients and animal models has indicated that NPY may have a role in the disease pathogenesis. Increased NPY levels were found to correlate with disease progression in ALS patients. Similarly, NPY expression is increased in the motor cortex of ALS mice by end stages of the disease. Although the functional consequence of increased NPY levels in ALS is currently unknown, NPY has been shown to exert a diverse range of neuroprotective roles in other neurodegenerative diseases; through modulation of potassium channel activity, increased production of neurotrophins, inhibition of endoplasmic reticulum stress and autophagy, reduction of excitotoxicity, oxidative stress, neuroinflammation and hyperexcitability. Several of these mechanisms and signalling pathways are heavily implicated in the pathogenesis of ALS. Therefore, in this review, we discuss possible effects of NPY and NPY-receptor signalling in the ALS disease context, as determining NPY's contribution to, or impact on, ALS disease mechanisms will be essential for future studies investigating the NPY system as a therapeutic strategy in this devastating disease.

Increased Interleukin-6 Levels in the Astrocyte-Derived Exosomes of Sporadic Amyotrophic Lateral Sclerosis Patients

Neuroinflammation plays an important role in amyotrophic lateral sclerosis (ALS) pathogenesis. However, it is difficult to evaluate inflammation of the central nervous system (CNS) or the relationship between neuroinflammation and disease progression in ALS patients. Recent advances in the field of exosomes and CNS-derived exosomes extraction technology provide the possibility of measuring the inflammatory status in the CNS without brain biopsy. In this pilot study, we extracted astrocyte-derived exosomes from the plasma of sporadic ALS patients and age-, sex-matched healthy controls and determined Interleukin-6 (IL-6) levels by an enzyme-linked immunosorbent assay (ELISA). The IL-6 levels in astrocyte-derived exosomes were increased in sALS patients and positively associated with the rate of disease progression. However, the association between IL-6 levels and disease progression rate was limited to patients whose disease duration were less than 12 months. These data suggest an increased inflammatory cascade in the CNS of sALS patients. Our pilot study demonstrates that CNS-derived exosomes could be useful to reveal neuroinflammation of the CNS in ALS patients.

Rethinking to riluzole mechanism of action: the molecular link among protein kinase CK1δ activity, TDP-43 phosphorylation, and amyotrophic lateral sclerosis pharmacological treatment.

Rethinking to riluzole mechanism of action: the molecular link among protein kinase CK1δ activity, TDP-43 phosphorylation, and amyotrophic lateral sclerosis pharmacological treatment.

ALS-Associated E478G Mutation in Human OPTN (Optineurin) Promotes Inflammation and Induces Neuronal Cell Death.

Amyotrophic Lateral Sclerosis (ALS) is a group of neurodegenerative disorders that featured with the death of motor neurons, which leads to loss of voluntary control on muscles. The etiologies vary among different subtypes of ALS, and no effective management or medication could be provided to the patients, with the underlying mechanisms incompletely understood yet. Mutations in human Optn (Optineurin), particularly E478G, have been found in many ALS patients. In this work, we report that NF-κB activity was increased in Optn knockout (Optn−/−) MEF (mouse embryonic fibroblast) cells expressing OPTN of different ALS-associated mutants especially E478G. Inflammation was significantly activated in mice infected with lenti-virus that allowed overexpression of OPTNE478G mutation in the motor cortex, with marked increase in the secretion of pro-inflammatory cytokines as well as neuronal cell death. Our work with both cell and animal models strongly suggested that anti-inflammation treatment could represent a powerful strategy to intervene into disease progression in ALS patients who possess the distinctive mutations in OPTN gene.

Neuronal apoptosis inhibitory protein is implicated in amyotrophic lateral sclerosis symptoms

The delineation of the molecular pathology underlying amyotrophic lateral sclerosis (ALS) is being hampered by the lack of suitable biomarkers. We have previously reported that bromocriptine upregulates the endogenous antioxidative factor, neuronal apoptosis inhibitory protein (NAIP), sustains motor function and slows disease progression in ALS patients, implying the NAIP’s implication in ALS. Here, we aimed to verify a correlation of NAIP level with disease progression in ALS patients. The amount of NAIP in mononuclear cells (MNC) from peripheral blood from ALS patients (n = 18) and the age matched healthy controls (n = 12) was validated by NAIP-Dot blotting. Notably, the MNC-NAIP level in ALS patients (0.62 ± 0.29 ng) was nearly half of that in the healthy controls (1.34 ± 0.61 ng, P = 0.0019). Furthermore, the MNC-NAIP level in ALS patients and their ALS Functional Rating Scale-Revised (ALSFRS-R) score were evaluated through 1 year. Regression analysis of the MNC-NAIP vs ALSFRS-R indicated that a higher amount of MNC-NAIP was associated with a smaller change in ALSFRS-R at 12 months (R2 = 0.799; P = 0.016), suggesting that a progressive increment of the MNC-NAIP led to slower ALS progression. Our present report implies that NAIP will have broad implications for ALS symptoms as a risk factor and a promising prognostic biomarker.

Synaptic Failure: Focus in an Integrative View of ALS.

From early description by Charcot, the classification of the Amyotrophic Lateral Sclerosis (ALS) is evolving from a subtype of Motor Neuron (MN) Disease to be considered rather a multi-systemic, non-cell autonomous and complex neurodegenerative disease. In the last decade, the huge amount of knowledge acquired has shed new insights on the pathological mechanisms underlying ALS from different perspectives. However, a whole vision on the multiple dysfunctional pathways is needed with the inclusion of information often excluded in other published revisions. We propose an integrative view of ALS pathology, although centered on the synaptic failure as a converging and crucial player to the etiology of the disease. Homeostasis of input and output synaptic activity of MNs has been proved to be severely and early disrupted and to definitively contribute to microcircuitry alterations at the spinal cord. Several cells play roles in synaptic communication across the MNs network system such as interneurons, astrocytes, microglia, Schwann and skeletal muscle cells. Microglia are described as highly dynamic surveying cells of the nervous system but also as determinant contributors to the synaptic plasticity linked to neuronal activity. Several signaling axis such as TNFα/TNFR1 and CX3CR1/CX3CL1 that characterize MN-microglia cross talk contribute to synaptic scaling and maintenance, have been found altered in ALS. The presence of dystrophic and atypical microglia in late stages of ALS, with a decline in their dynamic motility and phagocytic ability, together with less synaptic and neuronal contacts disrupts the MN-microglia dialogue, decreases homeostatic regulation of neuronal activity, perturbs “on/off” signals and accelerates disease progression associated to impaired synaptic function and regeneration. Other hotspot in the ALS affected network system is the unstable neuromuscular junction (NMJ) leading to distal axonal degeneration. Reduced neuromuscular spontaneous synaptic activity in ALS mice models was also suggested to account for the selective vulnerability of MNs and decreased regenerative capability. Synaptic destabilization may as well derive from increased release of molecules by muscle cells (e.g. NogoA) and by terminal Schwann cells (e.g. semaphorin 3A) conceivably causing nerve terminal retraction and denervation, as well as inhibition of re-connection to muscle fibers. Indeed, we have overviewed the alterations on the metabolic pathways and self-regenerative capacity presented in skeletal muscle cells that contribute to muscle wasting in ALS. Finally, a detailed footpath of pathologic changes on MNs and associated dysfunctional and synaptic alterations is provided. The oriented motivation in future ALS studies as outlined in the present article will help in fruitful novel achievements on the mechanisms involved and in developing more target-driven therapies that will bring new hope in halting or delaying disease progression in ALS patients.

Association between nutritional status and disease severity using the amyotrophic lateral sclerosis (ALS) functional rating scale in ALS patients

ObjectiveThe nutritional status of patients with amyotrophic lateral sclerosis (ALS) has been shown to be associated with mortality. However, there have not been, to our knowledge, any studies on the association between nutritional status and disease severity. The present study investigated the hypothesis that nutritional status was negatively associated with disease severity using the ALS functional rating scale (ALSFRS-R). MethodsOne hundred ninety-three Korean ALS patients were divided into tertiles based on their ALSFRS-R score. Dietary intake was measured using 24 h recall and nutritional status was determined by body mass index (BMI) and geriatric nutritional risk index (GNRI). ResultsBMI and GNRI were significantly lower in patients in the lowest tertile of ALSFRS-R. BMI and GNRI also correlated with ALSFRS-R score, bulbar score, albumin levels, total lymphocyte count, and total daily energy expenditure. Intakes of energy and most nutrients were significantly lower in patients in the lowest tertiles of ALSFRS-R, but significances disappeared after adjusting for energy intake. Intakes of vegetables, grains, seasonings, and oils were also significantly lower in patients in the lowest tertile of ALSFRS-R. In addition, patients in the lowest tertile of ALSFRS-R were significantly younger at disease onset, had a longer duration of ALS, less regular exercise, and less sun exposure. ConclusionNutritional status, as assessed by BMI and GNRI, was negatively associated with disease severity using ALSFRS-R. The present study suggested that intake of nutrients decreases with disease progression in ALS patients.

Erythropoietin modulates the immune-inflammatory response of a SOD1G93A transgenic mouse model of amyotrophic lateral sclerosis (ALS)

Temporal patterns of inflammatory cytokine levels reflect the immune-inflammatory role in pathogenic mechanisms of SOD1 animal model of Amyotrophic Lateral Sclerosis (ALS) and these cytokines have important roles in both toxic and protective functions depending on the stage of disease progression in ALS patients. Erythropoietin (EPO) has various neuroprotective effects, including the reduction of inflammation, the enhancement of survival signals, and the prevention of neuronal cell death. This study was undertaken to evaluate the temporal pattern of inflammatory cytokine levels induced by EPO treatment in the SOD1G93A mice model of ALS. We treated mice with 5 IU of EPO per gram of animal weight once every other week after the mice were 60 days old, and pro/anti-inflammatory cytokines were analyzed at 30, 60, 90, and 120 days of age. In untreated controls, pro-inflammatory cytokines (IFN-γ, TNF-α, IL-1β, CCL2 (MCP-1), CCL5 (RANTES), CXCL10 (IP-10), and IL-17A) were gradually increased with aging. In contrast, increment of anti-inflammatory cytokines (IL-4, IL-10, and TGF-β) showed the highest level at 90 days of age and their levels were remarkably faded until 120 days of age. EPO treatment, however, showed significantly decreased level of pro-inflammatory cytokines. And, up-regulated levels of anti-inflammatory cytokines with EPO were highly maintained until 120 days. In addition, the treatment of EPO delayed symptom onset, prolonged time of rotarod failure, and showed more preserved number of motoneurons. These findings suggest that EPO may be a potential therapeutic candidate having ability to modulate immune-inflammation in ALS

Body mass index (BMI) as predictor of ALSFRS-R score decline in ALS patients

Recent studies of amyotrophic lateral sclerosis (ALS) suggest that body mass index (BMI) predicts patients’ survival in a curvilinear manner. We sought to determine the relationship of initial BMI to decline in the revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) score over time. We used data from the high dose Coenzyme-Q10 in ALS (QALS) clinical trial, with in-person ALSFRS-R interviews at baseline and nine months (n = 150). Multiple regression analysis allowed adjustment for a range of predictors. The final analysis, adjusted for age and FVC, indicated a significant, non-linear association of BMI with the change of ALSFRS-R over time (p < 0.01). The smallest decline was at BMI of 30. Among non-obese patients (BMI < 30, n = 126), higher BMI was associated with slower ALSFRS-R decline (p = 0.03). Among obese patients (BMI ≥ 30, n = 24), higher BMI was associated, although not significantly, with faster decline (p = 0.17). In conclusion, for ALS patient with BMI less than 30, higher initial BMI predicts slower functional decline. For patients with BMI greater than 30, higher initial BMI predicts more rapid decline. These results indicate that previous, apparently contradictory results can be reconciled, and suggest that initial BMI may help predict disease progression in ALS patients.

FUS-NLS/Transportin 1 complex structure provides insights into the nuclear targeting mechanism of FUS and the implications in ALS.

The C-terminal nuclear localization sequence of FUsed in Sarcoma (FUS-NLS) is critical for its nuclear import mediated by transportin (Trn1). Familial amyotrophic lateral sclerosis (ALS) related mutations are clustered in FUS-NLS. We report here the structural, biochemical and cell biological characterization of the FUS-NLS and its clinical implications. The crystal structure of the FUS-NLS/Trn1 complex shows extensive contacts between the two proteins and a unique α-helical structure in the FUS-NLS. The binding affinity between Trn1 and FUS-NLS (wide-type and 12 ALS-associated mutants) was determined. As compared to the wide-type FUS-NLS (KD = 1.7 nM), each ALS-associated mutation caused a decreased affinity and the range of this reduction varied widely from 1.4-fold over 700-fold. The affinity of the mutants correlated with the extent of impaired nuclear localization, and more importantly, with the duration of disease progression in ALS patients. This study provides a comprehensive understanding of the nuclear targeting mechanism of FUS and illustrates the significance of FUS-NLS in ALS.

Relationships between Disease Progression and Serum Levels of Lipid, Urate, Creatinine and Ferritin in Japanese Patients with Amyotrophic Lateral Sclerosis: A Cross-Sectional Study

Previous studies have reported distinct serological profiles of lipid, urate and ferritin in Western patients with amyotrophic lateral sclerosis (ALS). We aimed to examine the levels of these serological factors and their relationship to disease progression in Japanese ALS patients. Ninety-two patients with definite or probable ALS who fulfilled the revised El Escorial criteria were analyzed for clinical and serological variables. Serological data at the time diagnosed with ALS were compared to those of 92 age/sex/body mass index-matched healthy controls. Compared to controls, urate and creatinine (Cr) levels were decreased and ferritin levels were increased significantly in sera of male and female patients with ALS. Significant increases of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride levels were found in female ALS patients. The annual decline of ALS Functional Rating Scale-Revised (ALS-FRS) and forced vital capacity (FVC) were inversely correlated with serum TC, LDL-C, Cr and urate levels, and were positively correlated with serum ferritin levels. Multivariate analysis showed that the rapid worsening of annual ALS-FRS and FVC was associated with serum levels of TC, LDL-C, Cr, urate and ferritin. The present study indicated that serum levels of TC, LDL-C, Cr, urate and ferritin were correlated with clinical deterioration in ALS patients. These results are similar to those in Western patients. Metabolic and nutritional conditions of lipid, urate and iron could contribute to disease progression in ALS patients. Further studies investigating high nutrition diets and iron chelation for the treatment of ALS are warranted.

Correlation of cerebral spinal fluid pH and HCO3- with disease progression in ALS

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal disease, which is characterized by progressive degeneration of spinal and bulbar innervating motor neurons. However, the underlying mechanisms of motor neuron death remain poorly understood. Several candidate disease biomarkers have been detected in cerebrospinal fluid of ALS patients. The present study analyzed various cerebral spinal fluid gas parameters in ALS patients and compared these values to controls, as well as patients with cervical spondylosis, Parkinson syndrome, and spinocerebellar degeneration. Cerebral spinal fluid pH positively correlated with the ALS functional rating scale in total and limb-type ALS patients. In addition, cerebral spinal fluid pH positively correlated with shorter disease duration (less than 22weeks). These results suggested that cerebral spinal fluid pH provides a biomarker for ALS and could reflect mechanisms of disease progression in ALS patients.

Update on the glutamatergic neurotransmitter system and the role of excitotoxicity in amyotrophic lateral sclerosis.

Excitotoxicity may play a role in certain disorders of the motor system thought to be caused by environmentally acquired toxins, including lathyrism and domoic acid poisoning. Motor neurons appear to be particularly susceptible to toxicity mediated via alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-kainate receptors. There is a body of evidence implicating glutamatergic toxicity as a contributory factor in the selective neuronal injury occurring in amyotrophic lateral sclerosis (ALS). Interference with glutamate-mediated toxicity is so far the only neuroprotective therapeutic strategy that has shown benefit in terms of slowing disease progression in ALS patients. Biochemical studies have shown decreased glutamate levels in central nervous system (CNS) tissue and increased levels in the cerebrospinal fluid (CSF) of ALS patients. CSF from ALS patients is toxic to neurons in culture, apparently via a mechanism involving AMPA receptor activation. There is evidence for altered expression and function of glial glutamate transporters in ALS, particularly excitatory amino acid transporter 2 (EAAT2). Abnormal splice variants of EAAT2 have been detected in human CNS. Mitochondrial dysfunction may contribute to excitotoxicity in ALS. Induction of neuronal nitric oxide synthase and cyclooxygenase 2 in ALS may also lead to significant interactions with regulation of the glutamate transmitter system. Certain features of motor neurons may predispose them to the neurodegenerative process in ALS, such as the cell size, mitochondrial activity, neurofilament content, and relative lack of certain calcium-binding proteins and molecular chaperones. Motor neurons appear vulnerable to toxicity mediated by calcium-permeable AMPA receptors. The relatively low expression of the glutamate receptor 2 (GluR2) AMPA receptor subunit and the high current density caused by the large number and density of cell surface AMPA receptors are potentially important factors that may predispose to such toxicity.