Plasma creatinine and amyotrophic lateral sclerosis prognosis: a systematic review and meta-analysis

Blood diagnostic and prognostic biomarkers in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a devastating neurodegenerative disease for which the current treatment approaches remain severely limited. The principal pathological alterations of the disease include the selective degeneration of motor neurons in the brain, brainstem, and spinal cord, as well as abnormal protein deposition in the cytoplasm of neurons and glial cells. The biological markers under extensive scrutiny are predominantly located in the cerebrospinal fluid, blood, and even urine. Among these biomarkers, neurofilament proteins and glial fibrillary acidic protein most accurately reflect the pathologic changes in the central nervous system, while creatinine and creatine kinase mainly indicate pathological alterations in the peripheral nerves and muscles. Neurofilament light chain levels serve as an indicator of neuronal axonal injury that remain stable throughout disease progression and are a promising diagnostic and prognostic biomarker with high specificity and sensitivity. However, there are challenges in using neurofilament light chain to differentiate amyotrophic lateral sclerosis from other central nervous system diseases with axonal injury. Glial fibrillary acidic protein predominantly reflects the degree of neuronal demyelination and is linked to non-motor symptoms of amyotrophic lateral sclerosis such as cognitive impairment, oxygen saturation, and the glomerular filtration rate. TAR DNA-binding protein 43, a pathological protein associated with amyotrophic lateral sclerosis, is emerging as a promising biomarker, particularly with advancements in exosome-related research. Evidence is currently lacking for the value of creatinine and creatine kinase as diagnostic markers; however, they show potential in predicting disease prognosis. Despite the vigorous progress made in the identification of amyotrophic lateral sclerosis biomarkers in recent years, the quest for definitive diagnostic and prognostic biomarkers remains a formidable challenge. This review summarizes the latest research achievements concerning blood biomarkers in amyotrophic lateral sclerosis that can provide a more direct basis for the differential diagnosis and prognostic assessment of the disease beyond a reliance on clinical manifestations and electromyography findings.

Routine blood biochemical biomarkers in amyotrophic lateral sclerosis: Systematic review and cohort analysis

Introduction: Blood biochemical biomarkers, including urate, creatinine, albumin, and creatine kinase, have been shown to be useful in ALS. To provide further information about the roles of these four biomarkers roles we performed a systematic review. In addition, we also performed a new study of the role of these biomarkers in predicting survival, using data from our local ALS cohort. Methods: (1) Using established databases and other sources, we searched for papers about the use of urate, creatinine, albumin, and creatine kinase as biomarkers in ALS. Included articles were reviewed for information about biomarker levels in ALS and controls, association with markers of functional decline, and survival. (2) For our local ALS cohort, we performed survival analysis, Cox-proportionate-hazard ratio and ROC curves to investigate the use of these biomarkers in predicting survival. Results: (1) For systematic review, 104 papers were included. There was some variability in the findings. For urate, there was evidence of decreased levels in ALS, with higher levels associated ith longer survival. For creatinine, there was evidence of decreased levels in ALS, and higher levels correlated with longer survival. For albumin, some reports of reduced levels in ALS, but no consistent association with survival. For creatine kinase, some reports of increased levels in ALS, with inconsistent association with survival. (2) For the local ALS cohort there was evidence that urate and creatinine were associated with survival, but no significant association with survival. There was less evidence for albumin and CK. Discussion: This study provides support for further studies of these readily available biochemical measurement as bioamerkers in ALS.

Phosphatemia is an Independent Prognostic Factor in Amyotrophic Lateral Sclerosis

OBJECTIVE

The objective of this study was to evaluate the prognostic value of several muscle damage biomarkers.

METHODS

Data from Piemonte and Valle d'Aosta Amyotrophic Lateral Sclerosis (PARALS) were considered for this study. Survival was defined as the time from diagnosis to death, tracheostomy, or the censoring date. Blood levels of potassium, creatinine, creatine kinase, phosphorus, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) diagnosis were evaluated as potential prognostic biomarkers. A Cox model was developed for each biomarker and adjusted for sex, onset age, onset site, and diagnostic delay. Significant findings from PARALS were evaluated in the Pooled Resource Open-Access Amyotrophic Lateral Sclerosis Clinical Trials (PRO-ACT) database. Additionally, a joint model was constructed to evaluate the prognostic role of phosphatemia slope over time using longitudinal data from PRO-ACT.

RESULTS

A total of 1,444 and 1,023 patients were included in the PARALS and PRO-ACT cohorts, respectively. Only creatinine (hazard ratio [HR] = 0.65, 95% confidence interval [CI] = 0.50-0.85) and phosphorus (HR = 1.14, 95% CI = 1.04-1.24) showed a significant association with survival in the PARALS cohort. These findings were further validated in the PRO-ACT cohort (creatinine HR = 0.21, 95% CI = 0.13-0.35, p < 0.0001; phosphorus HR = 2.35, 95% CI = 1.13-4.88, p = 0.02). Longitudinal data from the PRO-ACT database showed that an increase of 0.1 mmol/l per month in phosphate levels was also associated with a HR of 8.26 (95% CI = 1.07-96.6, p = 0.044).

INTERPRETATION

Creatininemia was confirmed as a prognostic marker in amyotrophic lateral sclerosis (ALS). Additionally, both phosphatemia levels at diagnosis and its rate of change over time were identified as a potential prognostic marker for ALS. As with other blood biomarkers, phosphate levels are cost-effective and minimally invasive to measure, supporting their potential use in clinical trials. ANN NEUROL 2025.

Does Lumbar Puncture Still Have Clinical Value for Patients with Amyotrophic Lateral Sclerosis?

Background: The relationship between routine cerebrospinal fluid (CSF) testing and clinical and prognostic data in amyotrophic lateral sclerosis (ALS) remains unclear. Additionally, biochemical data have never been correlated with markers of neurodegeneration. The purpose of this study is to determine whether lumbar puncture may still have clinical utility in ALS. Methods: We collected the CSF profiles of 140 ALS subjects. CSF protein, albumin, IgG, IgG index, albumin quotient (QAlb), t-tau, p-tau, and Aβ42 were analyzed. Results: Approximately one-quarter of ALS patients had elevated levels of protein, albumin, and QAlb in the CSF, but these were not associated with clinical or survival data. Among the neurodegeneration markers, the percentage of patients with abnormal values ranged from 26.3% to 35.4%. The p-tau/t-tau ratio and Aβ42 were correlated with both the ALS progression rate and the time from diagnosis to death. Aβ42 was the prognostic marker most strongly associated with survival. Conclusions: The lack of correlation between biochemical CSF findings and the clinical and/or prognostic status of ALS suggests that these markers have no clinical value. However, neurodegeneration markers that are easily measurable in clinical laboratories, particularly Aβ42, may be useful at the time of diagnosis for predicting ALS survival and progression rate.

Systemic Innate Immune System Restoration as a Therapeutic Approach for Neurodegenerative Disease: Effects of NP001 on Amyotrophic Lateral Sclerosis (ALS) Progression

BACKGROUND/OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a diagnosis that incorporates a heterogeneous set of neurodegenerative processes into a single progressive and uniformly fatal disease making the development of a uniformly applicable therapeutic difficult. Recent multinational ALS natural history incidence studies have identified systemic chronic activation of the innate immune system as a major risk factor for developing ALS. Persistent immune activation in patients with ALS leads to loss of muscle and lowering of serum creatinine. The goal of the current study was to test whether the slowing of nerve and muscle destruction in NP001-treated ALS patients compared with controls in phase 2 studies would lead to extension of survival.

METHODS

Phase 2 clinical studies with NP001, an intravenously administered form of the innate immune system regulator NaClO2, are now reporting long-term survival benefits for drug recipients vs. placebo controls after only six months of intermittent treatment. As a prodrug, NP001 is converted by macrophages to taurine chloramine, a long-lived regulator of inflammation. We performed a pooled analysis of all patients who had completed the studies in two six-month NP001 phase 2 trials. Changes in respiratory vital capacity and the muscle mass product, creatinine, defined treated patients who, compared to placebo, had up to a year of extended survival.

CONCLUSIONS

The observed longer survival in ALS patients with the greatest inflammation-associated muscle loss provides further evidence that ALS is a disease of ongoing innate immune dysfunction and that NP001 is a disease-modifying drug with sustained clinical activity.

Comparative analysis of neurofilaments and biomarkers of muscular damage in amyotrophic lateral sclerosis

Diagnosis of the fatal neurodegenerative disease amyotrophic lateral sclerosis is challenging. Neurofilaments, indicative of neuronal damage, along with creatine kinase, creatinine, myoglobin, and troponin T, representing muscular damage, have been identified as promising fluid biomarkers. This study aims to comprehensively assess and compare their diagnostic and prognostic potential in a 'real-world' cohort of patients with amyotrophic lateral sclerosis. About 77 patients with amyotrophic lateral sclerosis and its clinical variants, and 26 age- and sex-matched controls with various neuromuscular and neurodegenerative diseases, were retrospectively included in this monocentric, cross-sectional study. Neurofilaments in cerebrospinal fluid and biomarkers of muscular damage in serum were measured and correlated with demographic features, motor function, survival time, clinical phenotypes, and the extent of upper and lower motor neuron involvement. Neurofilament, myoglobin, and troponin T concentrations were higher in patients with amyotrophic lateral sclerosis compared to disease controls. Higher neurofilament levels correlated with lower motor function and faster disease progression rate, while higher creatine kinase and creatinine concentrations were linked to preserved motor function. In contrast, troponin T elevation indicated poorer fine and gross motor functions. Increased neurofilament levels were associated with shorter survival, whereas biomarkers of muscular damage lacked survival correlation. Neurofilament concentrations were higher in classical amyotrophic lateral sclerosis than in progressive muscular atrophy, while myoglobin and troponin T levels were elevated in progressive muscular atrophy compared to primary lateral sclerosis. Neurofilaments were predominantly linked to upper motor neuron involvement. Our findings confirmed the robust diagnostic and prognostic value of neurofilaments in amyotrophic lateral sclerosis. Elevated neurofilament concentrations were associated with higher disease severity, faster disease progression, shorter survival, and predominant upper motor neuron degeneration. Biomarkers of muscular damage were inferior in distinguishing amyotrophic lateral sclerosis from other neuromuscular and neurodegenerative diseases. However, they may serve as complementary biomarkers and support in discriminating clinical variants of amyotrophic lateral sclerosis.

Urinary biomarkers for amyotrophic lateral sclerosis: candidates, opportunities and considerations

Amyotrophic lateral sclerosis is a relentless neurodegenerative disease that is mostly fatal within 3-5 years and is diagnosed on evidence of progressive upper and lower motor neuron degeneration. Around 15% of those with amyotrophic lateral sclerosis also have frontotemporal degeneration, and gene mutations account for ∼10%. Amyotrophic lateral sclerosis is a variable heterogeneous disease, and it is becoming increasingly clear that numerous different disease processes culminate in the final degeneration of motor neurons. There is a profound need to clearly articulate and measure pathological process that occurs. Such information is needed to tailor treatments to individuals with amyotrophic lateral sclerosis according to an individual's pathological fingerprint. For new candidate therapies, there is also a need for methods to select patients according to expected treatment outcomes and measure the success, or not, of treatments. Biomarkers are essential tools to fulfil these needs, and urine is a rich source for candidate biofluid biomarkers. This review will describe promising candidate urinary biomarkers of amyotrophic lateral sclerosis and other possible urinary candidates in future areas of investigation as well as the limitations of urinary biomarkers.

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

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

Current State and Future Directions in the Diagnosis of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by loss of upper and lower motor neurons, resulting in progressive weakness of all voluntary muscles and eventual respiratory failure. Non-motor symptoms, such as cognitive and behavioral changes, frequently occur over the course of the disease. Considering its poor prognosis with a median survival time of 2 to 4 years and limited causal treatment options, an early diagnosis of ALS plays an essential role. In the past, diagnosis has primarily been determined by clinical findings supported by electrophysiological and laboratory measurements. To increase diagnostic accuracy, reduce diagnostic delay, optimize stratification in clinical trials and provide quantitative monitoring of disease progression and treatment responsivity, research on disease-specific and feasible fluid biomarkers, such as neurofilaments, has been intensely pursued. Advances in imaging techniques have additionally yielded diagnostic benefits. Growing perception and greater availability of genetic testing facilitate early identification of pathogenic ALS-related gene mutations, predictive testing and access to novel therapeutic agents in clinical trials addressing disease-modified therapies before the advent of the first clinical symptoms. Lately, personalized survival prediction models have been proposed to offer a more detailed disclosure of the prognosis for the patient. In this review, the established procedures and future directions in the diagnostics of ALS are summarized to serve as a practical guideline and to improve the diagnostic pathway of this burdensome disease.

Analysis of the Failure of Removal of the Urinary Catheter for Patients With Intracerebral Hemorrhage Postoperatively

BACKGROUND

We conducted this study to assess the value of clinically relevant data for predicting the failure of removing urinary catheters among patients with intracerebral hemorrhage postoperatively.

MATERIALS AND METHODS

We retrospectively analyzed the medical records of all patients with intracerebral hemorrhage who underwent surgery for removal of intracerebral hematoma between January 2014 and December 2019, all of whom retained their urinary catheter. The patients were classified into 2 groups. Group A included patients who underwent successful removal of the catheter while group B included patients who underwent a failed removal. Univariate analysis was performed to determine the relationship between the failure of catheter removal and the patients' preoperative clinical characteristics. Independent prognostic predictors were identified using multivariate analyses.

RESULTS

The site of intracerebral hematoma ( P =0.004), volume of hematoma ( P <0.001), intraventricular hemorrhage ( P <0.001), admitted Glasgow Coma Scale (GCS) ( P <0.001), GCS before urinary catheter removal ( P <0.001), smoking ( P =0.011), herniation ( P <0.001), urine protein ( P =0.013), creatinine ( P =0.037), and timing of urinary catheter removal ( P <0.001) were significantly different among the 2 groups. Multiple logistical regression analysis indicated that GCS before urinary catheter removal (odds ratio=1.171; 95% confidence interval=1.050-1.306; P =0.005) and timing for urinary catheter removal (odds ratio=0.962; 95% confidence interval=0.944-0.981; P <0.001) were associated with failure of urinary catheter removal.

CONCLUSIONS

This study demonstrated that GCS before urinary catheter removal and the timing of urinary catheter removal are independent factors associated with failure of urinary catheter removal among patients with intracerebral hemorrhage.

Plasma taurine is an axonal excitability-translatable biomarker for amyotrophic lateral sclerosis

Although various body fluid biomarkers for amyotrophic lateral sclerosis (ALS) have been reported, no biomarkers specifically reflecting abnormalities in axonal excitability indices have currently been established. Capillary electrophoresis time-of-flight mass spectrometry and liquid chromatography time-of-flight mass spectrometry were used to perform a comprehensive metabolome analysis of plasma from seven ALS patients and 20 controls, and correlation analysis with disease phenotypes was then performed in 22 other ALS patients. Additionally, electrophysiological studies of motor nerve axonal excitability were performed in all ALS patients. In the ALS and control groups, levels of various metabolites directly associated with skeletal muscle metabolism, such as those involved in fatty acid β-oxidation and the creatine pathway, were detected. Receiver operating characteristic curve analysis of the top four metabolites (ribose-5-phosphate, N6-acetyllysine, dyphylline, 3-methoxytyrosine) showed high diagnostic accuracy (area under the curve = 0.971) in the ALS group compared with the control group. Furthermore, hierarchical cluster analysis revealed that taurine levels were correlated with the strength-duration time constant, an axonal excitability indicator established to predict survival. No significant effects of diabetes mellitus and treatment (Riluzole and Edaravone) on this relationship were detected in the study. Therefore, plasma taurine is a potential novel axonal excitability-translatable biomarker for ALS.

Predictors of survival in patients with amyotrophic lateral sclerosis: A large meta-analysis

Background

The survival time of amyotrophic lateral sclerosis (ALS) is greatly variable and protective or risk effects of the potential survival predictors are controversial. Thus, we aim to undertake a comprehensive meta-analysis of studies investigating non-genetic prognostic and survival factors in patients with ALS.

Methods

A search of relevant literature from PubMed, Embase, Cochrane library and other citations from 1^st January 1966 to 1^st December 020 was conducted. Random-effects models were conducted to pool the multivariable or adjusted hazard ratios (HR) by Stata MP 16.0. PROSPERO registration number: CRD42021256923.

Findings

A total of 5717 reports were identified, with 115 studies meeting pre-designed inclusion criteria involving 55,169 ALS patients. Five dimensions, including demographic, environmental or lifestyle, clinical manifestations, biochemical index, therapeutic factors or comorbidities were investigated. Twenty-five prediction factors, including twenty non-intervenable and five intervenable factors, were associated with ALS survival. Among them, NFL (HR:3.70, 6.80, in serum and CSF, respectively), FTD (HR:2.98), ALSFRS-R change (HR:2.37), respiratory subtype (HR:2.20), executive dysfunction (HR:2.10) and age of onset (HR:1.03) were superior predictors for poor prognosis, but pLMN or pUMN (HR:0.32), baseline ALSFRS-R score (HR:0.95), duration (HR:0.96), diagnostic delay (HR:0.97) were superior predictors for a good prognosis. Our results did not support the involvement of gender, education level, diabetes, hypertension, NIV, gastrostomy, and statins in ALS survival.

Interpretation

Our study provided a comprehensive and quantitative index for assessing the prognosis for ALS patients, and the identified non-intervenable or intervenable factors will facilitate the development of treatment strategies for ALS.

Funding

This study was supported by the National Natural Science Fund of China (Grant No. 81971188), the 1.3.5 project for disciplines of excellence, West China Hospital, Sichuan University (Grant No. 2019HXFH046), and the Science and Technology Bureau Fund of Sichuan Province (No. 2019YFS0216).

Biomarkers in amyotrophic lateral sclerosis: a review of new developments

PURPOSE OF REVIEW

This review draws together the most recent findings in ALS biomarker research from biochemical, imaging and neurophysiology techniques.

RECENT FINDINGS

The potential of circulating RNA is highlighted, including new retrieval techniques. With ongoing genetic clinical trials, the need for pharmacodynamic biomarkers is essential. There is a strong case for neurofilament proteins being validated in ALS; their biomarker profile is discussed. Oxidative stress and neuroinflammation studies offer insight into disease mechanisms and offer good biomarker potential. Recent metabolic studies include investigation of lipid profiles, creatinine and ferritin. The potential of chitinase proteins as pharmacodynamic and prognostic biomarkers is highlighted. The role of tau and amyloidβ is debated, as evidenced by the articles presented here. Proteomic approaches provide unbiased discoveries of novel biomarkers, together with confirmation of previous findings. The use of imaging techniques is outlined to demonstrate selective atrophy, volume loss, muscle and tract involvement. In-vivo imaging is discussed with reference to histone deacetylase, oxidative stress, neuroinflammation and metabolic changes. New applications of electrophysiology demonstrate objective muscle biomarkers and brain network perturbations.

SUMMARY

The biomarker research field continues to provide insight into the disease. Multicentre collaborations are needed to validate these promising recent findings.

Plasma Creatinine Level Does Not Predict Respiratory Function in Amyotrophic Lateral Sclerosis

In amyotrophic lateral sclerosis (ALS) lower plasma creatinine level has been associated with shorter survival and faster functional decline. It has not been clear if creatinine is associated with respiratory outcome. We analyzed retrospectively a population of unselected ALS patients. Multiple-regression and Cox-regression analyses were performed. We included 233 patients, mean age 62.8, mean disease duration of 18.6 months. At baseline, creatinine was significantly associated with ALSFRS-R, but not with its decline rate. No predictive value was disclosed for FVC, its decline rate, or with survival. We did not confirm that creatinine is a marker of respiratory outcome.

Decreased serum creatinine levels predict short survival in amyotrophic lateral sclerosis

Objective

To explore the associations between serum creatinine and creatine kinase (CK) levels with survival in male and female ALS patients.

Methods

A prospective cohort study was carried out including 346 ALS patients with repeated serum creatinine and CK measurements. Kaplan Meier analysis and multivariable Cox regression were used to perform survival analysis.

Results

There were 218 male and 128 female patients, and the males had significantly higher baseline serum creatinine and CK levels than females. After multivariable Cox regression analysis, lower baseline serum creatinine levels were associated with a short survival in both male (≤61 μmol/L, HR: 1.629; 95%CI: 1.168–2.273) and female ALS patients (≤52 μmol/L, HR: 1.677; 95%CI: 1.042–2.699), whereas, the serum CK levels were not correlated with survival. Besides, creatinine levels were positively associated with ALSFRS‐R scores, and inversely with the decline rate of ALSFRS‐R per month. During follow‐up, serum creatinine levels tended to be decreased along with the disease progression, and the higher decline rate of creatinine per month (>1.5) showed significantly shorter survival, compared to the lower group (≤1.5) (30.0 months vs. 65.0 months, Chi square = 28.25, P < 0.0001).

Interpretation

Serum creatinine could be a reliable and easily accessible prognostic chemical marker for ALS, and decreased baseline creatinine levels could predict a poor prognosis and a short survival in both male and female ALS patients.

Creatine kinase in the diagnosis and prognostic prediction of amyotrophic lateral sclerosis: a retrospective case-control study

Creatine kinase is a muscle enzyme that has been reported at various levels in different studies involving patients with amyotrophic lateral sclerosis. In the present retrospective case-control study, we included 582 patients with amyotrophic lateral sclerosis and 582 age- and sex-matched healthy controls. All amyotrophic lateral sclerosis participants received treatment in the Department of Neurology, West China Hospital, China, between May 2008 and December 2018. Serum creatine kinase levels in patients with amyotrophic lateral sclerosis were significantly higher than those in healthy controls. Subgroup analysis revealed that serum creatine kinase levels in men were higher than those in women in both amyotrophic lateral sclerosis patients and healthy controls. Compared with patients with bulbar-onset amyotrophic lateral sclerosis, patients with limb-onset amyotrophic lateral sclerosis had higher creatine kinase levels. Spearman's correlation analysis revealed that serum creatine kinase levels were not correlated with body mass index, Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised score, or progression rate. After adjusting for prognostic covariates, higher log creatine kinase values were correlated with higher overall survival in the amyotrophic lateral sclerosis patients. We also investigated the longitudinal changes in serum creatine kinase levels in 81 amyotrophic lateral sclerosis patients; serum creatine kinase levels were decreased at the second blood test, which was sampled at least 6 months after the first blood test. Together, our results suggest that serum creatine kinase levels can be used as an independent factor for predicting the prognosis of amyotrophic lateral sclerosis patients. This study received ethical approval from the Ethics Committee of West China Hospital, China (approval No. 2015(236)) on December 23, 2015.

Conditioned Medium from Cells Overexpressing TDP-43 Alters the Metabolome of Recipient Cells

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by the progressive death of both upper and lower motor neurons. The disease presents a poor prognosis, and patients usually die 2-5 years after the onset of symptoms. The hallmark of this disease is the presence of phosphorylated and ubiquitinated aggregates containing trans-active response DNA-binding protein-43 (TDP-43) in the cytoplasm of motor neurons. TDP-43 pathology has been associated with multiple pathways in ALS, such as metabolic dysfunction found in patients and in in vivo models. Recently, it has been described as a "prion-like" protein, as studies have shown its propagation in cell culture from ALS brain extract or overexpressed TDP-43 in co-culture and conditioned medium, resulting in cytotoxicity. However, the cellular alterations that are associated with this cytotoxicity require further investigation. Here, we investigated the effects of conditioned medium from HEK293T (Human Embryonic Kidney 293T) cells overexpressing TDP-43 on cellular morphology, proliferation, death, and metabolism. Although we did not find evidence of TDP-43 propagation, we observed a toxicity of TDP-43-conditioned medium and altered metabolism. These results, therefore, suggest (1) that cells overexpressing TDP-43 produce an extracellular environment that can perturb other cells and (2) that TDP-43 propagation alone may not be the only potentially cytotoxic cell-to-cell mechanism.

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.

Is There a Role for Vitamin D in Amyotrophic Lateral Sclerosis? A Systematic Review and Meta-Analysis

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative condition characterized by the progressive loss of motor neurons. Patients usually die 3–5 years after diagnosis from respiratory failure. Several studies investigated the role of vitamin D as a biomarker or a therapeutic option for ALS patients. To clarify the scientific evidence, we performed a systematic review and different meta-analyses regarding the potential role of vitamin D in ALS.

Methods: We performed a systematic review of clinical trials, cohorts, and case–control studies retrieved from PubMed, EMBASE, and Cochrane databases reporting vitamin D levels as a putative biomarker for ALS diagnosis or prognosis or the effect of vitamin D supplementation in ALS patients. Whenever possible, data were pooled using a random-effects model, with an assessment of heterogeneity.

Results: Out of 2,996 articles retrieved, we finally included 13 research articles, 12 observational studies (50% prospective), and 1 clinical trial. We found that ALS patients had slightly lower levels of vitamin D than controls (mean difference −6 ng/ml, 95% CI [−10.8; −1.3]), but important confounding factors were not considered in the studies analyzed. We found no relationship between vitamin D levels and ALS functional rate score—revised (ALSFRS-R), with highly heterogeneous results. Discordant results were reported in three studies regarding survival. Finally, five studies reported the effects of vitamin D supplementation with discordant results. Two of them showed a small improvement, whereas two others showed a deleterious effect on ALSFRS-R. One very small clinical trial with important methodological limitations showed some improvement in ALSFRS-R with high doses of vitamin D compared with normal doses.

Conclusions: Our review did not find evidence to support the role of vitamin D on ALS diagnosis, prognosis, or treatment. Most studies had important limitations, mostly regarding the risk of bias for not considering confounding factors. Vitamin D supplementation should be offered to ALS patients to avoid other health issues related to vitamin D deficiency, but there is not enough evidence to support the use of vitamin D as a therapy for ALS.

A nerve conduction study predicts the prognosis of sporadic amyotrophic lateral sclerosis

OBJECTIVE

To clarify the relationship between nerve conduction study (NCS) and prognosis in patients with amyotrophic lateral sclerosis (ALS).

METHODS

We included 190 patients with sporadic ALS. We used onset age, sex, onset site (bulbar vs. spinal), revised El Escorial criteria category (definite vs. others), and the King's clinical systems, and the Milano-Torino (MiToS) functional staging systems, and decline rates of revised ALS functional rating scale (ALSFRS-R) as known prognostic factors. An NCS was performed on the median, ulnar, tibial, and sural nerves. The endpoint was death or the introduction of tracheostomy positive-pressure ventilation. Multivariate analysis for each NCS variable, known prognostic factors was performed using Cox stepwise proportional hazards analysis. Univariate analysis was performed for NCS variables that showed a significant association with prognosis in multivariate analysis. Survival was analyzed with a Kaplan-Meier curve and log-rank test.

RESULTS

The Cox model identified the compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes of the median nerve as prognostic factors. In the log-rank test, patients with higher median nerve CMAP amplitude had a significantly better prognosis than those with lower amplitude, regardless of age. And prognosis was better in the group with lower median nerve SNAP amplitude only in patients younger than the 25th percentile (~ 57 years).

CONCLUSIONS

CMAP and SNAP amplitudes of the median nerve are considered to be independent prognostic factors of sporadic ALS.

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.