Serum uric acid levels in patients with amyotrophic lateral sclerosis: a meta-analysis

Association Between Serum Uric Acid and Abdominal Aortic Calcification in Adults Aged 40 to 80 years: A Retrospective Cross-Sectional Study

There are numerous causes of abdominal aortic calcification (AAC), among which the relationship between serum uric acid and AAC still needs to be investigated further. The aim of this research was to ascertain whether serum uric acid is correlated with AAC. Our study included 3007 participants. We described the study population characteristics and utilized univariate analysis, stratified analysis, multiple equation regression analysis, smoothed curve fitting, and threshold effects analysis. AAC Total 24 score is used to reflect the range of aortic calcification at each vertebral level. As serum uric acid increased, the AAC Total 24 score first decreased and then increased. The fold point is located when serum uric is at 3.5 mg/dL. After adjusting for 16 covariates, the beta values for the groups with moderate and high serum uric acid levels were 0.34 and 0.53, respectively, compared with the low serum uric acid tertile group (P < .05). Our research indicates a negative correlation between serum acid level and AAC when serum uric acid <3.5 mg/dl, but it is positively correlated with the formation of AAC when serum uric acid >3.5 mg/dl.

The Impact of Serum Uric Acid on the Progression of Amyotrophic Lateral Sclerosis in Adults Aged 18 and Older: A Systematic Review

We have conducted this review to see if serum uric acid (UA) is associated with slowing amyotrophic lateral sclerosis (ALS) progression in adult patients who are at least 18 years old. Understanding the effects of this biomarker for future use is critical because of its easy accessibility. This systematic review paper examined five previous years of recent studies and reports, published in English and limited to human investigations from the Cochrane, PubMed, and Google Scholar databases. Using instruments for assessing the eligibility and quality of systematic and narrative reviews, we narrowed our search to 11 reports that show evidence of a positive association between high blood uric acid and the progression of ALS. However, this claim still needs confirmation by future studies to confirm that possibility. The results of this systematic review may provide a strong foundation for future studies on this biomarker, demonstrating the significance of blood uric acid levels in ALS and highlighting the necessity of using that biomarker to track the disease's progression.

Astrocytes: Dissecting Their Diverse Roles in Amyotrophic Lateral Sclerosis and Frontotemporal Dementia

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative disorders often co-occurring in the same patient, a feature that suggests a common origin of the two diseases. Consistently, pathological inclusions of the same proteins as well as mutations in the same genes can be identified in both ALS/FTD. Although many studies have described several disrupted pathways within neurons, glial cells are also regarded as crucial pathogenetic contributors in ALS/FTD. Here, we focus our attention on astrocytes, a heterogenous population of glial cells that perform several functions for optimal central nervous system homeostasis. Firstly, we discuss how post-mortem material from ALS/FTD patients supports astrocyte dysfunction around three pillars: neuroinflammation, abnormal protein aggregation, and atrophy/degeneration. Furthermore, we summarize current attempts at monitoring astrocyte functions in living patients using either novel imaging strategies or soluble biomarkers. We then address how astrocyte pathology is recapitulated in animal and cellular models of ALS/FTD and how we used these models both to understand the molecular mechanisms driving glial dysfunction and as platforms for pre-clinical testing of therapeutics. Finally, we present the current clinical trials for ALS/FTD, restricting our discussion to treatments that modulate astrocyte functions, directly or indirectly.

Prevalence of motor neuron diseases in gout patients: a nationwide population-based cohort study

BACKGROUND

Increased uric acid may have a protective effect in motor neuron diseases (MNDs). The association between gout, characterized by hyperuricemia, and MNDs was not investigated previously. To estimate the prevalence of MNDs in gout patients using the Health Insurance and Review Assessment (HIRA) database, a nationwide database of South Korea.

METHODS

The current descriptive study was conducted using the HIRA database. Subjects diagnosed with gout from 2011 to 2018 were included in this study. Among them, the annual prevalence of MNDs was analyzed, stratified by age and sex. Comorbidities including the Charlson Comorbidity Index score and type of prescribed gout-related drug were also demonstrated.

RESULTS

The age-adjusted prevalence of MNDs per 10⁵ persons ranged from 0.598 (95% confidence interval (CI): - 0.231-1.426) to 2.534 (95% CI: 1.100-3.968) between 2011 and 2018. Compared to previous reports, the prevalence of MNDs, especially amyotrophic lateral sclerosis (ALS), in gout patients was significantly lower than in the general population. None of the female gout patients were diagnosed with MNDs. Cerebrovascular accidents, vascular risk factors including hypertension, dyslipidemia, and diabetic complications, and the use of uric acid-lowering agents were more common in gout patients with MNDs than in those without MNDs.

CONCLUSION

This study adds to the evidence of MND prevalence in gout patients. Gout might have a protective effect against the risk of MNDs.

Protective Effects of Lovastatin in a Population-Based ALS Study and Mouse Model

OBJECTIVE

The objective of this study was to use a novel combined pharmacoepidemiologic and amyotrophic lateral sclerosis (ALS) mouse model approach to identify potential motor neuron protective medications.

METHODS

We constructed a large, population-based case-control study to investigate motor neuron disease (MND) among US Medicare beneficiaries aged 66 to 90 in 2009. We included 1,128 incident MND cases and 56,400 age, sex, race, and ethnicity matched controls. We calculated MND relative risk for >1,000 active ingredients represented in Part D (pharmacy) claims in 2006 to 2007 (>1 year before diagnosis/reference). We then applied a comprehensive screening approach to select medications for testing in SOD1^G93A mice: sulfasalazine, telmisartan, and lovastatin. We treated mice with the human dose equivalent of the medication or vehicle via subcutaneous osmotic pump before onset of weakness. We then assessed weight, gait, and survival. In additional mice, we conducted histological studies.

RESULTS

We observed previously established medical associations for MND and an inverse dose-response association between lovastatin and MND, with 28% reduced risk at 40 mg/day. In SOD1^G93A mouse studies, sulfasalazine and telmisartan conferred no benefit, whereas lovastatin treatment delayed onset and prolonged survival. Lovastatin treated mice also had less microgliosis, misfolded SOD1, and spinal motor neuron loss in the ventral horn.

INTERPRETATION

Lovastatin reduced the risk of ALS in humans, which was confirmed in an ALS mouse model by delayed symptom onset, prolonged survival, and preservation of motor neurons. Although further studies to understand the mechanism are required, lovastatin may represent a potential neuroprotective therapy for patients with ALS. These data demonstrate the utility of a combined pharmacoepidemiologic and mouse model approach. ANN NEUROL 2023.

Biologic targets of prescription medications and risk of neurodegenerative disease in United States Medicare beneficiaries

OBJECTIVE

To identify prescription medications associated with a lower risk of three neurodegenerative diseases: Parkinson disease, Alzheimer disease, and amyotrophic lateral sclerosis.

METHODS

We conducted a population-based, case-control study of U.S. Medicare beneficiaries in 2009 (42,885 incident neurodegenerative disease cases, 334,387 randomly selected controls). Using medication data from 2006-2007, we categorized all filled medications according to their biological targets and mechanisms of action on those targets. We used multinomial logistic regression models, while accounting for demographics, indicators of smoking, and health care utilization, to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for 141 target-action pairs and each neurodegenerative disease. For target-action pairs inversely associated with all three diseases, we attempted replication in a cohort study that included an active comparator group. We constructed the cohort by following controls forward for incident neurodegenerative disease from the beginning of 2010 until death or end of 2014, i.e., up to five years after the two-year exposure lag. We used Cox proportional hazards regression while accounting for the same covariates.

RESULTS

The most consistent inverse association across both studies and all three neurodegenerative diseases was for xanthine dehydrogenase/oxidase blockers, represented by the gout medication, allopurinol. Allopurinol was associated with a 13-34% lower risk for each neurodegenerative disease group in multinomial regression, and a mean reduction of 23% overall, as compared to individuals who did not use allopurinol. In the replication cohort we observed a significant 23% reduction for neurodegenerative disease in the fifth year of follow-up, when comparing allopurinol users to non-users, and more marked associations with an active comparator group. We observed parallel associations for a related target-action pair unique to carvedilol.

DISCUSSION/CONCLUSION

Xanthine dehydrogenase/oxidase blockade might reduce risk of neurodegenerative disease. However, further research will be necessary to confirm that the associations related to this pathway are causal or to examine whether this mechanism slows progression.

[The influence of uric acid on the course of amyotrophic lateral sclerosis]

Uric acid has antioxidant and neuroprotective properties. A number of studies show that high levels of uric acid may have a positive influence on the course of amyotrophic lateral sclerosis (ALS), especially in males. The frequency of ALS is lower in patients with gout than in the general population. We present a case of a patient with gout and slowly progressive ALS. More research is needed on the potential role of uric acid in ALS and other neurodegenerative disorders.

Elevated serum uric acid is associated with cognitive improvement in older American adults: A large, population-based-analysis of the NHANES database

Background

The many studies revealing a connection between serum uric acid (SUA) and dementia have reported conflicting results. This study sought to investigate the relations between SUA and cognitive function in older adults.

Materials and methods

The sample was 2,767 American adults aged ≥60 years from the National Health and Nutrition Examination Survey 2011-2014. Cognitive performance was evaluated by the Consortium to Establish a Registry for Alzheimer's Disease test, animal fluency test, digit symbol substitution test, and composite z-score. Multivariate linear regression analyses were conducted to estimate the association between SUA and cognitive function.

Results

SUA level and cognitive function were significantly, positively correlated. Age significantly correlated with the association between SUA and cognitive function.

Conclusion

These findings support a connection between SUA and cognition, showing a positive link between SUA and cognitive scores among older American adults. We contend that a slight rise in uric acid within the normal range is advantageous for enhanced cognition. To confirm the precise dose-time-response relation, more tests will be needed.

Serum Uric Acid Levels in Neurodegenerative Disorders: A Cross-Sectional Study

Background: Excessive oxidative stress may contribute to neurodegeneration by leading to protein aggregation and mitochondrial dysfunction. Uric acid (UA) is an important endogenous antioxidant that protects against oxidative stress, yet its exact role in neurodegeneration remains unclear. Objective: To explore the performance of serum UA in neurodegenerative disorders. Methods: A total of 839 controls and 840 patients, including Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), frontotemporal dementia (FTD), dementia with Lewy bodies (DLB), motor neuron disease (MND), Creutzfeldt-Jakob disease (CJD), and mixed dementia (MixD) were enrolled. Fasting serum UA levels were measured in all participants and compared between patients and controls. Linear regression models were utilized to explore possible relationships of serum UA with cognition, disease duration, age, and age of onset. Results: Compared to controls (355.48 ± 85.38 μmol/L), serum UA was significantly lower in AD (291.29 ± 83.49 μmol/L, p < 0.001), PD (286.95 ± 81.78 μmol/L, p < 0.001), PSP (313.32 ± 88.19 μmol/L, p < 0.001), FTD (313.89 ± 71.18 μmol/L, p = 0.001), and DLB (279.23 ± 65.51 μmol/L, p < 0.001), adjusting for confounding factors including age, gender, education, etc. In addition, serum UA was positively correlated with cognitive levels in all patients (Mini-Mental State Examination: r = 0.136, p = 0.001; and Montreal Cognitive Assessment Scale: r = 0.108, p = 0.009). Conclusion: Decreased levels of serum UA were correlated with AD, PD, PSP, FTD, and DLB, offering significant potential as a promisingly relevant, less-invasive marker of multiple neurodegenerative disorders.

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

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.

Nutrient Effects on Motor Neurons and the Risk of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is an incurable chronic progressive neurodegenerative disease with the progressive degeneration of motor neurons in the motor cortex and lower motor neurons in the spinal cord and the brain stem. The etiology and pathogenesis of ALS are being actively studied, but there is still no single concept. The study of ALS risk factors can help to understand the mechanism of this disease development and, possibly, slow down the rate of its progression in patients and also reduce the risk of its development in people with a predisposition toward familial ALS. The interest of researchers and clinicians in the protective role of nutrients in the development of ALS has been increasing in recent years. However, the role of some of them is not well-understood or disputed. The objective of this review is to analyze studies on the role of nutrients as environmental factors affecting the risk of developing ALS and the rate of motor neuron degeneration progression.

METHODS

We searched the PubMed, Springer, Clinical keys, Google Scholar, and E-Library databases for publications using keywords and their combinations. We analyzed all the available studies published in 2010-2020.

DISCUSSION

We analyzed 39 studies, including randomized clinical trials, clinical cases, and meta-analyses, involving ALS patients and studies on animal models of ALS. This review demonstrated that the following vitamins are the most significant protectors of ALS development: vitamin B12, vitamin E > vitamin C > vitamin B1, vitamin B9 > vitamin D > vitamin B2, vitamin B6 > vitamin A, and vitamin B7. In addition, this review indicates that the role of foods with a high content of cholesterol, polyunsaturated fatty acids, urates, and purines plays a big part in ALS development.

CONCLUSION

The inclusion of vitamins and a ketogenic diet in disease-modifying ALS therapy can reduce the progression rate of motor neuron degeneration and slow the rate of disease progression, but the approach to nutrient selection must be personalized. The roles of vitamins C, D, and B7 as ALS protectors need further study.

How Are Adenosine and Adenosine A2A Receptors Involved in the Pathophysiology of Amyotrophic Lateral Sclerosis?

Adenosine is extensively distributed in the central and peripheral nervous systems, where it plays a key role as a neuromodulator. It has long been implicated in the pathogenesis of progressive neurogenerative disorders such as Parkinson’s disease, and there is now growing interest in its role in amyotrophic lateral sclerosis (ALS). The motor neurons affected in ALS are responsive to adenosine receptor function, and there is accumulating evidence for beneficial effects of adenosine A_2A receptor antagonism. In this article, we focus on recent evidence from ALS clinical pathology and animal models that support dynamism of the adenosinergic system (including changes in adenosine levels and receptor changes) in ALS. We review the possible mechanisms of chronic neurodegeneration via the adenosinergic system, potential biomarkers and the acute symptomatic pharmacology, including respiratory motor neuron control, of A_2A receptor antagonism to explore the potential of the A_2A receptor as target for ALS therapy.

Association between higher serum uric acid levels within the normal physiological range and changes of lumbar spine bone mineral density in healthy Chinese postmenopausal women: a longitudinal follow-up study

OBJECTIVES

The aim of this study was to investigate whether higher serum uric acid (SUA) levels within the physiological range were associated with changes in lumbar spine bone mineral density (LBMD) in postmenopausal women without existing lumbar spine osteoporosis after a longitudinal follow-up of 3.09 years, and to further confirm the relationship between SUA and bone mineral density (BMD) in other sites such as femoral neck, total hip, and trochanter at follow-up.

METHODS

A longitudinal study of 175 healthy postmenopausal women without osteoporosis was conducted in Shenyang, China. BMD of the lumbar spine, femoral neck, total hip, and trochanter were measured using dual-energy x-ray absorptiometry at each visit. Pearson's correlation analysis and regression analyses were performed to determine any associations.

RESULTS

There were positive correlations between baseline SUA and BMD of the lumbar spine (P = 0.03), total hip (P = 0.04), and trochanter (P = 0.04). Moreover, higher baseline SUA levels were independently associated with LBMD decline and the odds ratio of the baseline SUA of the third quartile group was 0.12 (95% confidence interval, 0.02-0.70, P < 0.05), with P = 0.23 for the trend in baseline SUA when compared with participants in the lowest, first quartile group after adjustment for many potential confounding variables.

CONCLUSIONS

Higher SUA levels within the normal physiological range were independently associated with decreased LBMD, and SUA levels were positively related to the BMD of the lumbar spine, total hip, and trochanter in healthy Chinese postmenopausal women.

Molecular Pathology of ALS: What We Currently Know and What Important Information Is Still Missing

Despite an early understanding of amyotrophic lateral sclerosis (ALS) as a disease affecting the motor system, including motoneurons in the motor cortex, brainstem, and spinal cord, today, many cases involving dementia and behavioral disorders are reported. Therefore, we currently divide ALS not only based on genetic predisposition into the most common sporadic variant (90% of cases) and the familial variant (10%), but also based on cognitive and/or behavioral symptoms, with five specific subgroups of clinical manifestation—ALS with cognitive impairment, ALS with behavioral impairment, ALS with combined cognitive and behavioral impairment, the fully developed behavioral variant of frontotemporal dementia in combination with ALS, and comorbid ALS and Alzheimer’s disease (AD). Generally, these cases are referred to as amyotrophic lateral sclerosis-frontotemporal spectrum disorder (ALS-FTSD). Clinical behaviors and the presence of the same pathognomonic deposits suggest that FTLD and ALS could be a continuum of one entity. This review was designed primarily to compare neuropathological findings in different types of ALS relative to their characteristic locations as well as the immunoreactivity of the inclusions, and thus, foster a better understanding of the immunoreactivity, distribution, and morphology of the pathological deposits in relation to genetic mutations, which can be useful in specifying the final diagnosis.

Amyotrophic Lateral Sclerosis: Molecular Mechanisms, Biomarkers, and Therapeutic Strategies

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with the progressive loss of motor neurons, leading to a fatal paralysis. According to whether there is a family history of ALS, ALS can be roughly divided into two types: familial and sporadic. Despite decades of research, the pathogenesis of ALS is still unelucidated. To this end, we review the recent progress of ALS pathogenesis, biomarkers, and treatment strategies, mainly discuss the roles of immune disorders, redox imbalance, autophagy dysfunction, and disordered iron homeostasis in the pathogenesis of ALS, and introduce the effects of RNA binding proteins, ALS-related genes, and non-coding RNA as biomarkers on ALS. In addition, we also mention other ALS biomarkers such as serum uric acid (UA), cardiolipin (CL), chitotriosidase (CHIT1), and neurofilament light chain (NFL). Finally, we discuss the drug therapy, gene therapy, immunotherapy, and stem cell-exosomal therapy for ALS, attempting to find new therapeutic targets and strategies. A challenge is to study the various mechanisms of ALS as a syndrome. Biomarkers that have been widely explored are indispensable for the diagnosis, treatment, and prevention of ALS. Moreover, the development of new genes and targets is an urgent task in this field.

Serum Uric Acid Levels Predict Mortality Risk in Male Amyotrophic Lateral Sclerosis Patients

Objective: To explore the associations between serum uric acid levels with survival in male and female ALS patients. Methods: A longitudinal cohort study was carried out including 313 sporadic and 16 familial ALS patients with repeated serum uric acid measurements. Multivariate Cox regression models were used to evaluate the survival-related factors. Results: There were 207 male and 122 female, and the mean age of onset was 55.7 ± 11.2 years old. The male patients had significantly higher baseline uric acid levels than that in female patients (342.4 ± 91.4 vs. 279.3 ± 71.4 μmol/L; p < 0.0001). The uric acid levels were inversely associated with the decline rate of ALSFRS-R per month (ΔALSFRS-R). After multivariate Cox regression analysis, a survival advantage was found in male, but not female, with higher serum uric acid levels. In males, a shorter diagnostic delay (≤10 m), lower BMI at baseline (≤18.70 kg/m²), faster disease progression (ΔALSFRS-R > 0.63), and lower baseline uric acid levels (≤292 μmol/L, HR: 1.936; 95% CI: 1.334-2.810) were associated with a shorter survival. During follow-up, the serum uric acid levels were not significantly altered over time. Conclusion: There is an inverse correlation between baseline serum uric acid levels and risk of death, prominently in male ALS patients.

The value of serum uric acid as a prognostic biomarker in amyotrophic lateral sclerosis: Evidence from a meta-analysis

OBJECTIVE

To determine the value of uric acid (UA) as a prognostic biomarker for amyotrophic lateral sclerosis (ALS) using a meta-analysis of hazard ratio-based studies.

METHODS

We included data from Tokushima University (47 patients with ALS) and three previous studies (1835 patients with ALS) with a hazard ratio (HR) identified by a systematic computational search. A total of four studies and 1882 patients were enrolled in the pooled analysis. We pooled HRs of death or tracheostomy, which were estimated by a Cox proportional hazard model, using a random-effects model. Heterogeneity was assessed by Q statistic, and a p value < 0.1 was considered significant heterogeneity. Furthermore, sensitivity analysis was performed to assess the effect of each single study and the robustness of the summary effect. We evaluated publication bias by visual assessment of the funnel plot and Egger's test, and adjusted the bias using a trim-and-fill method.

RESULTS

This meta-analysis revealed that UA could be a prognostic factor for ALS (all, HR = 0.87, p < 0.001; men, HR = 0.83, p < 0.001; women, HR = 0.76, p < 0.001). The included studies were homogeneous (all, p = 0.43; men, p = 0.9; women, p = 0.49). Sensitivity analysis confirmed the robustness of these summary effects. Publication bias was detected, which was adjusted for by a trim-and-fill method. The adjusted results showed significant summary effects (all, HR = 0.88, p = 0.002; men, HR = 0.83, p < 0.001; women, HR = 0.77, p < 0.001).

CONCLUSION

The present meta-analysis suggests that the serum UA level could be a prognostic biomarker in patients with ALS. Sensitivity analyses and the trim-and-fill method supported the robustness of these results.

Emerging Drugs for the Treatment of Amyotrophic Lateral Sclerosis: A Focus on Recent Phase 2 Trials

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease involving both upper and lower motor neurons and resulting in increasing disability and death 3-5 years after onset of symptoms. Over 40 large clinical trials for ALS have been negative, except for Riluzole that offers a modest survival benefit, and Edaravone that modestly reduces disease progression in patients with specific characteristics. Thus, the discovery of efficient disease modifying therapy is an urgent need.

AREAS COVERED

Although the cause of ALS remains unclear, many studies have demonstrated that neuroinflammation, proteinopathies, glutamate-induced excitotoxicity, microglial activation, oxidative stress, and mitochondrial dysfunction may play a key role in the pathogenesis. This review highlights recent discoveries relating to these diverse mechanisms and their implications for the development of therapy. Ongoing phase 2 clinical trials aimed to interfere with these pathophysiological mechanisms are discussed.

EXPERT OPINION

This review describes the challenges that the discovery of an efficient drug therapy faces and how these issues may be addressed. With the continuous advances coming from basic research, we provided possible suggestions that may be considered to improve performance of clinical trials and turn ALS research into a 'fertile ground' for drug development for this devastating disease.

Metabolomics: A Tool to Understand the Impact of Genetic Mutations in Amyotrophic Lateral Sclerosis

Metabolomics studies performed in patients with amyotrophic lateral sclerosis (ALS) reveal a set of distinct metabolites that can shed light on the pathological alterations taking place in each individual. Metabolites levels are influenced by disease status, and genetics play an important role both in familial and sporadic ALS cases. Metabolomics analysis helps to unravel the differential impact of the most common ALS-linked genetic mutations (as C9ORF72, SOD1, TARDBP, and FUS) in specific signaling pathways. Further, studies performed in genetic models of ALS reinforce the role of TDP-43 pathology in the vast majority of ALS cases. Studies performed in differentiated cells from ALS-iPSC (induced Pluripotent Stem Cells) reveal alterations in the cell metabolism that are also found in ALS models and ultimately in ALS patients. The development of metabolomics approaches in iPSC derived from ALS patients allow addressing and ultimately understanding the pathological mechanisms taking place in any patient. Lately, the creation of a "patient in a dish" will help to identify patients that may benefit from specific treatments and allow the implementation of personalized medicine.

The Association between Serum Uric Acid and Bone Mineral Density in Older Adults

OBJECTIVES

Uric acid has been found to be potentially protective in bone metabolism. We investigated the relationship between serum uric acid (sUA) and lumbar bone mineral density (BMD) among 4156 participants aged 60 years and over from the National Health and Nutrition Examination Survey (NHANES).

METHODS

To estimate the association between sUA and lumbar BMD, multivariate logistic regression analyses were conducted. Fitted smoothing curves and generalized additive models were also performed.

RESULTS

We found sUA positively correlated with lumbar BMD after adjusting for other confounders. On subgroup analyses, stratified by sex and race/ethnicity, the positive correlation of sUA with lumbar BMD remained in both men and women, as well as in whites and Mexican Americans, but not in blacks. In blacks, the association of sUA with lumbar BMD was an inverted U-shaped curve (inflection point: 7.5 mg/dL).

CONCLUSIONS

Our study revealed a positive relationship between sUA and lumbar BMD among most old adults. This association followed an inverted U-shaped curve among blacks.

Prognostic analysis of amyotrophic lateral sclerosis based on clinical features and plasma surface-enhanced Raman spectroscopy

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a wide range of survival times. We aimed to explore prognostic factors related to short survival based on clinical features and plasma metabolic signatures using surface-enhanced Raman spectroscopy (SERS). One hundred and thirty-eight sporadic ALS cases were enrolled serially, including 62 for the short-duration group (≤3 years) and 76 for the long-duration group (>3 years). Multivariate analysis showed that an older age of onset (>60 years; odds ratio [OR] = 3.98, 95% CI: 1.09-14.53), lower body mass index (BMI) (<18.5; OR = 6.80, 95% CI: 1.36-33.92), and lower ALSFRS-R score (<35; OR = 6.03, 95% CI: 1.42-25.63) were associated with higher odds of tracheotomy or death, while a higher uric acid (UA) level showed a protective effect (>356.36 μmol/L; OR = 0.19, 95% CI: 0.05-0.73). SERS analysis showed significant differences between the two groups, and pathway analysis highlighted five main metabolic pathways, including metabolisms of glutathione, pyrimidine, phenylalanine, galactose, and phenylalanine-tyrosine-tryptophan biosynthesis. In conclusion, age of onset, BMI, ALSFRS-R score and UA, together with dysregulation of glucose, amino acid, nucleic acid, and antioxidant metabolism contributed to disease progression, and are therefore potential therapeutic targets for ALS.

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.

Shortage of Cellular ATP as a Cause of Diseases and Strategies to Enhance ATP

Germline mutations in cellular-energy associated genes have been shown to lead to various monogenic disorders. Notably, mitochondrial disorders often impact skeletal muscle, brain, liver, heart, and kidneys, which are the body’s top energy-consuming organs. However, energy-related dysfunctions have not been widely seen as causes of common diseases, although evidence points to such a link for certain disorders. During acute energy consumption, like extreme exercise, cells increase the favorability of the adenylate kinase reaction 2-ADP -> ATP+AMP by AMP deaminase degrading AMP to IMP, which further degrades to inosine and then to purines hypoxanthine -> xanthine -> urate. Thus, increased blood urate levels may act as a barometer of extreme energy consumption. AMP deaminase deficient subjects experience some negative effects like decreased muscle power output, but also positive effects such as decreased diabetes and improved prognosis for chronic heart failure patients. That may reflect decreased energy consumption from maintaining the pool of IMP for salvage to AMP and then ATP, since de novo IMP synthesis requires burning seven ATPs. Similarly, beneficial effects have been seen in heart, skeletal muscle, or brain after treatment with allopurinol or febuxostat to inhibit xanthine oxidoreductase, which catalyzes hypoxanthine -> xanthine and xanthine -> urate reactions. Some disorders of those organs may reflect dysfunction in energy-consumption/production, and the observed beneficial effects related to reinforcement of ATP re-synthesis due to increased hypoxanthine levels in the blood and tissues. Recent clinical studies indicated that treatment with xanthine oxidoreductase inhibitors plus inosine had the strongest impact for increasing the pool of salvageable purines and leading to increased ATP levels in humans, thereby suggesting that this combination is more beneficial than a xanthine oxidoreductase inhibitor alone to treat disorders with ATP deficiency.

Pilot trial of inosine to elevate urate levels in amyotrophic lateral sclerosis

OBJECTIVE

To test the safety, tolerability, and urate-elevating capability of the urate precursor inosine taken orally or by feeding tube in people with amyotrophic lateral sclerosis (ALS).

METHODS

This was a pilot, open-label trial in 25 participants with ALS. Treatment duration was 12 weeks. The dose of inosine was titrated at pre-specified time points to elevate serum urate levels to 7-8 mg/dL. Primary outcomes were safety (as assessed by the occurrence of adverse events [AEs]) and tolerability (defined as the ability to complete the 12-week study on study drug). Secondary outcomes included biomarkers of oxidative stress and damage. As an exploratory analysis, observed outcomes were compared with a virtual control arm built using prediction algorithms to estimate ALSFRS-R scores.

RESULTS

Twenty-four out of 25 participants (96%) completed 12 weeks of study drug treatment. One participant was unable to comply with study visits and was lost to follow-up. Serum urate rose to target levels in 6 weeks. No serious AEs attributed to study drug and no AEs of special concern, such as urolithiasis and gout, occurred. Selected biomarkers of oxidative stress and damage had significant changes during the study period. Observed changes in ALSFRS-R did not differ from baseline predictions.

INTERPRETATION

Inosine appeared safe, well tolerated, and effective in raising serum urate levels in people with ALS. These findings, together with epidemiological observations and preclinical data supporting a neuroprotective role of urate in ALS models, provide the rationale for larger clinical trials testing inosine as a potential disease-modifying therapy for ALS.