Blood Neurofilament Light Chain: The Neurologist's Troponin?

[Is neurofilament light chain useful as a disease progression marker for ATTRv amyloidosis? A literature review]

ATTRv amyloidosis is an autosomal-dominant disorder characterized by mutations in the transthyretin (TTR) gene, systemic deposition of transthyretin amyloid fibrils, and progressive polyneuropathy. Current scoring systems developed for ATTRv amyloidosis to measure the severity of polyneuropathy are not sufficiently sensitive or are difficult to implement in daily practice. Results of phase 3 trials for oligonucleotide therapeutics and real-world evidence have shown that neurofilament light chain (NfL), a key structural component of axons, is a reliable blood biomarker for assessing disease progression and treatment response in patients with ATTRv amyloidosis with polyneuropathy. Because blood NfL levels can be affected by factors such as age, body mass index (BMI), and renal function, its significance in patient monitoring needs to be assessed carefully while considering the clinical characteristics of each patient.

NfL as a biomarker in ATTRv amyloidosis: potential and limitations

Hereditary transthyretin amyloidosis (ATTRv) presents unique challenges in diagnosis and monitoring due to its phenotypic and genetic heterogeneity. This study evaluates the utility of serum neurofilaments light chains (NfL) as a reliable biomarker of disease activity in patients carrying different pathogenic TTR variants. Twenty-eight ATTRv patients carrying the following mutations (p.Phe84Leu, p.Glu109Gln, p.Thr69Ala, p.Val50Met) as well as 8 carriers and 27 healthy control subjects underwent extensive examination, including serum NfL measurement, neuropathy impairment score for the lower limb (NIS-LL), compound autonomic dysfunction test (CADT), and polyneuropathy disability (PND) scores, at T0, T6 and T12. The study not only confirms the previously established correlation between serum NfL concentrations and disease severity scales but also extends these observations to the mutations reported here. Furthermore, the research highlights the potential of serum NfLs as discriminators between presymptomatic carriers and symptomatic patients, emphasizing their utility in predicting disease onset and facilitating timely intervention.

The role of Neurofilament light (NfL) and glial fibrillary acidic protein (GFAP) in MS and AQP4-NMOSD: Advancing clinical applications

Fluid biomarkers such as Glial Fibrillary Acidic Protein (GFAP) and Neurofilament Light (NfL) play important roles in the diagnosis, monitoring, and evaluation of therapeutic responses in conditions such as Multiple Sclerosis (MS) and Aquaporin-4 Neuromyelitis Optica Spectrum Disorder (AQP4-NMOSD). These biomarkers offer key insights into the underlying pathophysiological mechanisms of these diseases, enabling effective follow-up and personalized treatment approaches, which are essential for improving patient outcomes. Herein, we synthesize the structural attributes, functional roles, and clinical significance of GFAP and NfL in the context of MS and AQP4-NMOSD. We explore the critical implications of these biomarkers in disease manifestation and progression, emphasizing the necessity to develop standardized methodologies and multicentric studies to confirm their clinical applicability.

Quantitative proteomic analysis of the brain reveals the potential antidepressant mechanism of Jiawei Danzhi Xiaoyao San in a chronic unpredictable mild stress mouse model of depression

OBJECTIVE

To reveal the antidepressant mechanisms of Jiawei DanZhiXiaoYaoSan (,JD) in chronic unpredictable mild stress (CUMS)-induced depression in mice.

METHODS

Using the CUMS mouse model of depression, the antidepressant effects of JD were assessed using the sucrose preference test (SPT), forced swimming test (FST), and tail suspension test (TST). Tandem mass tag (TMT)-based quantitative proteomic analysis of the brain was performed following JD treatment. Hierarchical clustering, Gene Ontology function annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and protein-protein interactions (PPIs) were used to analyze differentially expressed proteins (DEPs), which were further validated using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting.

RESULTS

Behavioral tests confirmed the anti-depressant effects of JD, and bioinformatics analysis revealed 59 DEPs, including 33 up-regulated and 26 down-regulated proteins, between the CUMS and JD-M groups. KEGG and PPI analyses revealed that neuro-filament proteins and the Ras signaling pathway may be key targets of JD in the treatment of depression. qRT-PCR and Western blotting results demonstrated that CUMS reduced the protein expression of neurofilament light (NEFL) and medium (NEFM) and inhibited the phosphorylation of extracellular regulated kinase 1/2 (ERK1/2), whereas JD promoted the phosphorylation of ERK1/2 and up-regulated the protein expression of NEFL and NEFM.

CONCLUSIONS

The antidepressant mechanism of JD may be related to the up-regulation of p-ERK1/2 and neurofilament proteins.

Advancements in diagnosing Post-concussion Syndrome: insights into epidemiology, pathophysiology, neuropathology, neuroimaging, and salivary biomarkers

Post-Concussion Syndrome (PCS) represents a complex constellation of symptoms that persist following a concussion or mild traumatic brain injury (mTBI), with significant implications for patient care and outcomes. Despite its prevalence, diagnosing PCS presents considerable challenges due to the subjective nature of symptoms, the absence of specific diagnostic tests, and the overlap with other neurological and psychiatric conditions. This review explores the multifaceted diagnostic challenges associated with PCS, including the heterogeneity of symptom presentation, the limitations of current neuroimaging techniques, and the overlap of PCS symptoms with other disorders. We also discuss the potential of emerging biomarkers and advanced imaging modalities to enhance diagnostic accuracy and provide a more objective basis for PCS identification. Additionally, the review highlights the importance of a multidisciplinary approach in the diagnosis and management of PCS, integrating clinical evaluation with innovative diagnostic tools to improve patient outcomes. Through a comprehensive analysis of current practices and future directions, this review aims to shed light on the complexities of PCS diagnosis and pave the way for improved strategies in the identification and treatment of this condition.

Medical Digital Twin: A Review on Technical Principles and Clinical Applications

The usage of digital twins (DTs) is growing across a wide range of businesses. The health sector is one area where DT use has recently increased. Ultimately, the concept of digital health twins holds the potential to enhance human existence by transforming disease prevention, health preservation, diagnosis, treatment, and management. Big data's explosive expansion, combined with ongoing developments in data science (DS) and artificial intelligence (AI), might greatly speed up research and development by supplying crucial data, a strong cyber technical infrastructure, and scientific know-how. The field of healthcare applications is still in its infancy, despite the fact that there are several DT programs in the military and industry. This review's aim is to present this cutting-edge technology, which focuses on neurology, as one of the most exciting new developments in the medical industry. Through innovative research and development in DT technology, we anticipate the formation of a global cooperative effort among stakeholders to improve health care and the standard of living for millions of people globally.

Plastic harmful ingredients reduce the level of neurofilament light chain protein

Population exposure to plastics is increasing, and plasticizers are frequently detected in humans as important ingredients of plastic products. However, patterns of exposure to harmful ingredients of plastics and their effects on neurofilament light chain (NFL), a marker of active brain pathology, are currently inconclusive. Herein, we employed a range of statistical methods to thoroughly investigate the impact of 24 plastic hazardous ingredients and their varying exposure patterns on NFL concentrations in the blood of the general population in 533 participants. Generalized linear model revealed a positive correlation between Mono-isononyl phthalate and Mono (2-Ethyl- 5-Hydroxyhexyl) Phthalate (MEHHP) with NFL. Furthermore, a significant dose-response relationship was observed between MEHHP and NFL, while Butyl paraben and Mono (Hydroxy-Isononyl) Ester exhibited a distinct "inverted U-shaped" nonlinear pattern with NFL. Additionally, Weighted Quantile Sum model allowed us to identify the mixed effects of all 24 plastic hazardous ingredients, with Mono(2-Ethyl-5-Oxohexyl) Phthalate, Mono-isobutyl phthalate, Mon butyl Phthalate, Propyl paraben and Triclosan occupying prominent positions. Finally, the latent profile analysis categorized exposures into high, medium, and low patterns, confirming that higher exposure to plastic hazardous ingredients posed a significant risk factor for elevated NFL levels in the blood. Exposure to plastic hazardous ingredients significantly increases the risk of NFL, the present contributes to early detection and intervention to reduce the incidence of neurodevelopmental disorder.

The Impact of Cognitive Behavioral Therapy for Insomnia on Neurofilament Light and Phosphorylated Tau in Individuals with a Concussion

BACKGROUND

Concussions damage neurologic tissue, increasing release of intercellular proteins including phosphorylated Tau (pTau) and neurofilament light (NfL). Disrupted sleep from a concussion negatively impacts the ability of the glymphatic system to remove cellular waste from the brain.

OBJECTIVE

The purpose of this study was to determine if enhancing sleep using Cognitive Behavioral Therapy for Insomnia (CBT-I) impacts pTau and NFL levels following a concussion.

METHODS

This is pre/post intervention analysis of a larger wait-list control study. Participants had their blood sampled pre/post the CBT-I intervention which was analyzed using SIMOA analytics. Paired sampling statistics and linear regression models were used to examine how insomnia severity impacts pTau181 and NfL.

RESULTS

Twenty-eight participants were enrolled in this study. Age and baseline protein level were significantly associated with post-intervention protein levels, but post-intervention insomnia severity was not associated with post-intervention protein levels. About 50% of participants that had clinically meaningful change in insomnia and had a reduction in their NfL and pTau181 values.

CONCLUSIONS

Post-intervention insomnia was not associated with post-intervention NfL or pTau. Yet, on an individual level, ~50% of participants had a clinically meaningful change in insomnia and reduced level of NfL and pTau 18.1.

CLINICAL TRIAL REGISTRATION

NCT04885205 https://clinicaltrials.gov.

Cerebrospinal fluid neurofilament light chain levels in children with acquired demyelinating syndrome

Objective

To study the cerebrospinal fluid (CSF) neurofilament light chain (NfL) in pediatric acquired demyelinating syndrome (ADS) and its association with factors of laboratory and imaging results.

Methods

We analyzed clinical data from children with ADS collected from May 2020 to January 2021 at the Department of Neurology of Guangzhou Women and Children's Medical Center. Enzyme-linked immunosorbent assays were used to detect the CSF NfL of patients.

Results

Thirty pediatric ADS patients (17 male, 13 female) were included in the study. The most frequent diagnosis was uncategorized ADS (36.7%, 11/30), followed by acute disseminating encephalomyelitis (ADEM) (23.3%, 7/30), myelin oligodendrocyte glycoprotein antibody-associated disorder (MOGAD) (20.0%, 6/30), NMO (6.7%, 2/30), multiple sclerosis (MS) (6.7%, 2/30), and neuromyelitis optic spectrum disorders (NMOSD) (6.7%, 2/30). The median CSF NfL for the first time was 7,425.28 pg/ml (interquartile range, 1,273.51, >10,000 pg/ml). CSF NfL increase over normal value (<290.00 pg/ml for people younger than 30 years old) was seen in 98.7% of patients. Patients were divided into uncategorized ADS, ADEM, MOGAD, and MS/NMO/NMOSD groups, with no significant difference in CSF NfL between each group. The CSF NfL positively correlated with the immunoglobulin (Ig) G (ρ = 0.473) and IgE (ρ = 0.366). However, the CSF NfL did not correlate with CSF white blood count and CSF protein. Furthermore, there was no significant difference between patients with oligoclonal bands positive and without. The CSF NfL negatively correlated with interferon γ (ρ = -0.501), CD45 + CD3+ T (ρ = -0.466), CD45 + CD3 + CD4+ T (ρ = -0.466), and CD45 + CD3 + CD8+ T cells (ρ = -0.521). However, it did not correlate with CD45 + CD19+ B cells. CSF NfL in patients with cerebral white matter lesions in MRI was higher than in patients without. Moreover, the CSF NfL positively correlated with the number of brain MRI locations (ρ = 0.362). Nine patients underwent multiple detections of CSF NfL, and their CSF NfL for the last detection was not significantly different from the first.

Conclusions

The CSF NfL increases significantly in pediatric ADS, and it can be a biomarker of neuro-axonal injury and a good indication of the extent of lesions.

Relationship between longer sleep and serum neurofilament light chain in american adults: evidence from the 2013-2014 US national health and nutrition examination survey

BACKGROUND

Sleep disturbance is linked to neurodegenerative diseases and the related brain pathophysiology. Serum neurofilament light chain (NfL) is a reliable biomarker for neurological disorders. This study examined the association between sleep characteristics and serum NfL levels in American adults.

METHODS

In this cross-sectional study, data from the 2013-2014 US National Health and Nutrition Examination Survey were utilized. Participants were categorized into short (≤ 6 h), normal (7-8 h), and long (≥ 9 h) sleep groups based on their self-reported sleep durations. Sleep duration, trouble sleeping, and diagnosed sleep disorders were queried, forming "sleep pattern (healthy, moderate, and poor)." The association between sleep characteristics and serum NfL levels was assessed using multivariate linear regression models. Stratification and sensitivity analyses were conducted to determine the stability of results.

RESULTS

Overall, 1637 participants were included; among them, 48.2% were male and 51.8% were female (mean ± SD, age: 46.9 ± 15.5 years) and 38.8% reported sleeping for ≤ 6 h, 54.4% for 7-8 h, and 6.8% for ≥ 9 h. Participants with longer sleep duration, poor sleep pattern, diagnosed sleep disorders, or trouble sleeping exhibited higher serum NfL levels. A positive correlation was found between extended sleep and elevated serum NfL levels (Adjusted β = 4.82, 95%CI: 2.2, 7.44, P < 0.001), with no significant correlation observed in the short-sleep group or those with poor sleep pattern. Stratified and sensitivity analyses confirmed the robustness of the relationship between longer sleep and elevated serum NfL levels.

CONCLUSIONS

A long sleep duration is associated with higher serum NfL levels than a normal sleep duration in American adults.

Association between serum neurofilament light chains (sNfL) and neurologic disorders in a representative sample of US adults: a cross-sectional study

BACKGROUND

While increased neurofilament light chain (NfL) in serum concentrations are linked to the progression of several neurological conditions, their distribution and implications within the general adult population remain largely unexplored. The current research aims to clarify the relationship between serum NfL levels and neurological disorders in a broad and representative population sample.

METHODS

We utilized information gathered from 1751 adults involved in the 2013-2014 cycle of the National Health and Nutrition Examination Survey . Our analytical approach encompassed logistic regression, smoothed curve fitting, and subgroup analyses to identify potential correlations between serum NfL levels and neurological conditions, such as depression, severe hearing and visual impairments, stroke, subjective memory deficits, and sleep problems.

RESULTS

After adjusting for all confounders, we found that higher serum NfL levels were significantly associated with increased risks of depression, stroke, subjective memory deficits, and longer sleep duration (p < 0.05). Subgroup analyses supported these findings. Additionally, BMI significantly influenced the relationship between serum NfL levels and long-term subjective memory decline.

CONCLUSION

Our research shows that higher serum NfL levels are strongly related to an elevated risk for several neurological disorders. These findings highlight the role of serum NfL serving as a critical marker for early detection and monitoring of neurological conditions, emphasizing its importance in both clinical and public health settings.

Prevalence of elevated sNFL in a real-world setting: Results on 908 patients with different multiple sclerosis types and treatment conditions

BACKGROUND

In the field of research for new validated surrogate biomarkers of treatment efficacy, disease activity and progression in Multiple Sclerosis (MS), serum neurofilament light-chain (sNFL) are actually the best candidate for MS patient monitoring. However, before they can be implemented in clinical practice, their usefulness as additional red flag routine measure must be demonstrated. To tackle the problem, this real-life cross-sectional study at the Regional Referring Center for Multiple Sclerosis (CRESM) aims to characterize sNFL levels and prevalence of elevated sNFL, according to our age-dependent cut-off values, in a large group of patients with different types of MS and treatment conditions.

METHODS

908 serum samples from as many MS patients being admitted at CRESM for diagnostic definition and/or during routinary treatment monitoring were consecutively collected between January 2019 and January 2020. sNFL levels were measured by single molecule array (Simoa™) technology on SR-X instrument using NF-light assays (Quanterix); results were interpreted using previously published cut-off values.

RESULTS

Primary and Secondary Progressive MS (PPMS, SPMS) forms demonstrate higher levels and prevalence of elevated sNFL (PPMS= 32 %, SPMS= 21 %) compared to the Relapse and Remitting one (RRMS = 12 %). Besides, naïve samples of RRMS and PPMS subtypes showed higher prevalence of elevated sNFL (RRMS naïve= 31 %, PPMS naïve=67 %) compared to samples from patients treated for more than 12 months (RRMS treat>12m= 9 %, PPMS treat>12m= 19 %); treated SPMS patients demonstrated higher sNFL levels and a prevalence (22 %) of elevated sNFL compared to RRMS treated patients. Focusing on RRMS, no statistical difference was found between groups of patients treated for whatever time (up to or more than 60 months) and with either DMT type (high or low-efficacy DMT). Finally, RRMS patients treated with all DMTs for more than 12 months, with the exception of teriflunomide and alemtuzumab showed a prevalence of elevated sNFL in the range of 5-10 %.

CONCLUSION

in a real-world setting comprising about 1000 MS patients, sNFL quantification was elevated in 5-to-67 % of patients, in different MS forms and treatment conditions. Elevated levels of sNFL must be considered a red-flag suggesting the need of a further clinical monitoring in any circumstance, as it can be indicative of new inflammation, ongoing degeneration or co-morbidities. This study supports the introduction of sNFL quantification in everyday patient management.

Introducing neurofilament light chain measure in psychiatry: current evidence, opportunities, and pitfalls

The recent introduction of new-generation immunoassay methods allows the reliable quantification of structural brain markers in peripheral matrices. Neurofilament light chain (NfL), a neuron-specific cytoskeletal component released in extracellular matrices after neuroaxonal impairment, is considered a promising blood marker of active brain pathology. Given its sensitivity to a wide range of neuropathological alterations, NfL has been suggested for the use in clinical practice as a highly sensitive, but unspecific tool to quantify active brain pathology. While large efforts have been put in characterizing its clinical profile in many neurological conditions, NfL has received far less attention as a potential biomarker in major psychiatric disorders. Therefore, we briefly introduce NfL as a marker of neuroaxonal injury, systematically review recent findings on cerebrospinal fluid and blood NfL levels in patients with primary psychiatric conditions and highlight the opportunities and pitfalls. Current evidence suggests an elevation of blood NfL levels in patients with major depression, bipolar disorder, psychotic disorders, anorexia nervosa, and substance use disorders compared to physiological states. However, blood NfL levels strongly vary across diagnostic entities, clinical stage, and patient subgroups, and are influenced by several demographic, clinical, and analytical factors, which require accurate characterization. Potential clinical applications of NfL measure in psychiatry are seen in diagnostic and prognostic algorithms, to exclude neurodegenerative disease, in the assessment of brain toxicity for different pharmacological compounds, and in the longitudinal monitoring of treatment response. The high inter-individual variability of NfL levels and the lack of neurobiological understanding of its release are some of the main current limitations. Overall, this primer aims to introduce researchers and clinicians to NfL measure in the psychiatric field and to provide a conceptual framework for future research directions.

Normal value of neuron-specific enolase for predicting good neurological outcomes in comatose out-of-hospital cardiac arrest survivors

Research on prognostic factors for good outcomes in out-of-hospital cardiac arrest (OHCA) survivors is lacking. We assessed whether normal levels of normal neuron-specific enolase (NSE) value would be useful for predicting good neurological outcomes in comatose OHCA survivors treated with targeted temperature management (TTM). This registry-based observational study with consecutive adult (≥18 years) OHCA survivors with TTM who underwent NSE measurement 48 hours after cardiac arrest was conducted from October 2015 to November 2022. Normal NSE values defined as the upper limit of the normal range by the manufacturer (NSE <16.3 μg/L) and guideline-suggested (NSE < 60 μg/L) were examined for good neurologic outcomes, defined as Cerebral Performance Categories ≤2, at 6 months post-survival. Among 226 OHCA survivors with TTM, 200 patients who underwent NSE measurement were enrolled. The manufacturer-suggested normal NSE values (<16.3 μg/L) had a specificity of 99.17% for good neurological outcomes with a very low sensitivity of 12.66%. NSE <60 μg/L predicted good outcomes with a sensitivity of 87.34% and specificity of 72.73%. However, excluding 14 poor-outcome patients who died from multi-organ dysfunction excluding hypoxic brain injury, the sensitivity and specificity of normal NSE values were 12.66% and 99.07% of NSE < 16.3 μg/L, and 87.34% and 82.24% of NSE < 60 μg/L. The manufacturer-suggested normal NSE had high specificity with low sensitivity, but the guideline-suggested normal NSE value had a comparatively low specificity for good outcome prediction in OHCA survivors. Our data demonstrate normal NSE levels can be useful as a tool for multimodal appropriation of good outcome prediction.

The association of menopausal hormone levels with progression-related biomarkers in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) progression coincides temporally with menopause. However, it remains unclear whether the changes in disease course are related to the changes in reproductive hormone concentrations. We assessed the association of menopausal hormonal levels with progression-related biomarkers of MS and evaluated the changes in serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) levels during menopausal hormone therapy (MHT) in a prospective baseline-controlled design.

METHODS

The baseline serum estradiol, follicle stimulating hormone, and luteinizing hormone levels were measured from menopausal women with MS (n = 16) and healthy controls (HC, n = 15). SNfL and sGFAP were measured by single-molecule array. The associations of hormone levels with sNfL and sGFAP, and with Expanded Disability Status Scale (EDSS) and lesion load and whole brain volumes (WBV) in MRI were analyzed with Spearman's rank correlation and age-adjusted linear regression model. Changes in sNfL and sGFAP during one-year treatment with estradiol hemihydrate combined with cyclic dydrogesterone were assessed with Wilcoxon Signed Ranks Test.

RESULTS

In MS group, baseline estradiol had a positive correlation with WBV in MRI and an inverse correlation with lesion load, sNfL and sGFAP, but no correlation with EDSS. The associations of low estradiol with high sGFAP and low WBV were independent of age. During MHT, there was no significant change in sNfL and sGFAP levels in MS group while in HC, sGFAP slightly decreased at three months but returned to baseline at 12 months.

CONCLUSION

Our preliminary findings suggest that low estradiol in menopausal women with MS has an age-independent association with more pronounced brain atrophy and higher sGFAP and thus advanced astrogliosis which could partially explain the more rapid progression of MS after menopause. One year of MHT did not alter the sGFAP or sNfL levels in women with MS.

Plasma neurological biomarkers as a measure of neurotoxicity in pediatric dental general anesthesia: a prospective observational feasibility study

PURPOSE

Neurotoxicity concerns have been raised over general anesthesia and sedation medication use in children. Such concerns are largely based on animal studies, historical anesthetic agents, and assessment tools, thus warranting further investigations. Blood biomarkers in detecting neuronal inflammation and apoptosis are novel methods for detecting neuronal damage. Therefore, the aim of this feasibility study was to assess the usefulness of the levels of four plasma biomarkers in dental general anesthesia (DGA) as surrogate markers of neurotoxicity in children. The secondary aim was to compare changes in motor manipulative skills pre- and post-anesthetic exposure.

METHODS

This single-center prospective observational study included 22 healthy children aged between 3 and 6 years old who underwent DGA. Subclinical neurotoxicity was measured with a panel of four plasma biomarkers: Caspase-3, neuron-specific enolase (NSE), neurofilament light chain, and S100B at three time points (1; at start, 2; end and 3; on recovery from DGA). The Skillings-Mack test was used to identify the difference in the biomarker levels at three time points. Motor manipulative score assessment, prior and two weeks after DGA was also performed.

RESULTS

A total of 22 study participants (mean age = 5 ± 1 years) were included with a median DGA duration of 106 ± 28 min. A reduction in Caspase-3 levels was recorded, with pairwise comparison over three time points, reporting a statistical significance between time point 2 vs. 1 and time point 3 vs. 1. Although fluctuations in NSE levels were recorded, no significant changes were found following pairwise comparison analysis. Among other biomarkers, no significant changes over the three periods were recorded. Furthermore, no significant changes in manipulative motor scores were reported.

CONCLUSION

Caspase-3 reduced significantly in the short time frames during day-care DGA; this might be due to the relatively short anesthesia duration associated with dental treatment as compared with more extensive medical-related treatments. Therefore, further studies on Caspase-3 as a potential biomarker in pediatric DGA neurotoxicity are required to further ascertain results of this study.

Association between urinary glyphosate levels and serum neurofilament light chain in a representative sample of US adults: NHANES 2013-2014

BACKGROUND

Glyphosate, the herbicide with the highest global usage, has been found to have links to neurological impairment in some occupational studies. Neurofilament light chain (NfL) is a protein that is released into the bloodstream following neuroaxonal damage and has emerged as a reliable biomarker for various neurological disorders. However, no research has investigated the potential link between glyphosate exposure and neurological damage or serum NfL levels in the general population.

OBJECTIVE

The objective of this study was to assess the possible correlation between glyphosate exposure and serum NfL levels in a population that is representative of the United States.

METHODS

We analyzed data from 597 adults (aged ≥20 years) from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) to explore the potential correlation between urinary glyphosate levels and serum NfL levels.

RESULTS

We found a significant positive association between urinary glyphosate levels and serum NfL levels (ß-coefficient = 0.110; S.E. = 0.040; P = 0.015), indicating that higher levels of glyphosate exposure may be linked to higher levels of neuroaxonal damage. Furthermore, when glyphosate levels were divided into quintiles, we observed a significant trend of increasing mean NfL concentrations with increasing quintiles of glyphosate exposure (P for trend = 0.036). Notably, the association was more pronounced in certain subgroups, including those aged ≥40 years, non-Hispanic whites, and those with a BMI between 25 and 30.

IMPACT STATEMENT

This is the first research to suggest an association between glyphosate exposure and biomarkers indicative of neurological damage in general U.S. adults. If the correlation observed is causal, it raises concerns about the potential effects of glyphosate exposure on neurological health among U.S. adults. The study is noteworthy due to its representation of American adults aged 20 and above, as well as the use of reliable and comprehensive data from the NHANES database.

Treatment response and neurofilament light chain levels with long-term patisiran in hereditary transthyretin-mediated amyloidosis with polyneuropathy: 24-month results of an open-label extension study

BACKGROUND

Longitudinal changes in neurofilament light chain (NfL) levels were evaluated alongside prespecified clinical assessments 24 months into the patisiran Global open-label extension (OLE) study in patients with ATTRv amyloidosis with polyneuropathy.

METHODS

All patients enrolled in the Global OLE, from phase III APOLLO and phase II OLE parent studies, received patisiran. Assessments included measures of polyneuropathy (modified Neuropathy Impairment Score+7 (mNIS+7)), quality of life (QOL; Norfolk QOL-Diabetic Neuropathy questionnaire (Norfolk QOL-DN)), and plasma NfL.

RESULTS

Patients receiving patisiran in the parent study (APOLLO-patisiran, n = 137; phase II OLE-patisiran, n = 25) demonstrated sustained improvements in mNIS+7 (mean change from parent study baseline (95% confidence interval): APOLLO-patisiran -4.8 (-8.9, -0.6); phase II OLE-patisiran -5.8 (-10.5, -1.2)) and Norfolk QOL-DN (APOLLO-patisiran -2.4 (-7.2, 2.3)), and maintained reduced NfL levels at Global OLE 24 months. After initiating patisiran in the Global OLE, APOLLO-placebo patients (n = 49) demonstrated stabilized mNIS+7, improved Norfolk QOL-DN, and significantly reduced NfL levels. Patisiran continued to demonstrate an acceptable safety profile. Earlier patisiran initiation was associated with a lower exposure-adjusted mortality rate.

CONCLUSIONS

Long-term patisiran treatment led to sustained improvements in neuropathy and QOL, with NfL demonstrating potential as a biomarker for disease progression and treatment response in ATTRv amyloidosis with polyneuropathy.

Guidance for use of neurofilament light chain as a cerebrospinal fluid and blood biomarker in multiple sclerosis management

Neurofilament light chain (NfL) is a long-awaited blood biomarker that can provide clinically useful information about prognosis and therapeutic efficacy in multiple sclerosis (MS). There is now substantial evidence for this biomarker to be used alongside magnetic resonance imaging (MRI) and clinical measures of disease progression as a decision-making tool for the management of patients with MS. Serum NfL (sNfL) has certain advantages over traditional measures of MS disease progression such as MRI because it is relatively noninvasive, inexpensive, and can be repeated frequently to monitor activity and treatment efficacy. sNfL levels can be monitored regularly in patients with MS to determine change from baseline and predict subclinical disease activity, relapse risk, and the development of gadolinium-enhancing (Gd+) lesions. sNfL does not replace MRI, which provides information related to spatial localisation and lesion stage. Laboratory platforms are starting to be made available for clinical application of sNfL in several countries. Further work is needed to resolve issues around comparisons across testing platforms (absolute values) and normalisation (reference ranges) in order to guide interpretation of the results.

Serum neurofilament light chain for predicting delayed neurological sequelae after acute carbon monoxide poisoning

INTRODUCTION

Acute carbon monoxide (CO) poisoning survivors may experience persistent delayed neurological sequelae (DNS). No studies have investigated the serum neurofilament light chain (NFL) as a prognostic biomarker in acute CO poisoning. This study aimed to determine the serum NFL levels to predict the DNS after acute CO poisoning.

METHODS

Patients with acute CO poisoning who were consecutively admitted from October 2020 to September 2022 were included. The predictive performance of NFLs for the DNS was assessed through the analyses of the correlation, the logistic regression, and the receiver operating characteristic (ROC) curve.

RESULTS

Overall, 9.7% (15/155) of the patients had DNS. The serum NFLs in patients with DNS was 113.7 pg/mL, which is significantly higher than that in the non-DNS group (25.8 pg/mL; P < 0.001). Correlation analysis shows that the serum NFLs are positively correlated with DNS (r = 0.567, P < 0.001). After multiple adjustments, the serum NFLs are independently correlated with DNS [adjusted odds ratio 1.032; 95% confidence interval (CI) 1.001, 1.064; p = 0.043]. The ROC curve indicates an area under the curve (AUC) of 0.923 (95% CI 0.869, 0.960), with a sensitivity of 100% and a specificity of 84.3% at the best cutoff value of 73.4 pg/mL. Pairwise comparison shows that the AUC of the NFL is significantly higher than that of the neuron specific enolase (AUC = 0.779) using the Hanley and McNeil test (Z = 2.283, p = 0.022).

CONCLUSION

Serum NFL could be a biomarker of the DNS after acute CO poisoning.

Serum neurofilament light chain: a promising early diagnostic biomarker for hereditary transthyretin amyloidosis?

BACKGROUND AND PURPOSE

Hereditary transthyretin amyloidosis (ATTRv) is a life-threatening disease caused by mutations in the gene encoding transthyretin (TTR). The recent therapeutic advances have underlined the importance of easily accessible, objective biomarkers of both disease onset and progression. Preliminary evidence suggests a potential role in this respect for neurofilament light chain (NfL). In this study, the aim was to determine serum NfL (sNfL) levels in a late-onset ATTRv population and evaluate whether it might represent a reliable biomarker of disease onset (i.e., 'conversion' from the asymptomatic status to symptomatic disease in TTR mutation carriers).

METHODS

In all, 111 individuals harbouring a pathogenic TTR variant (61 symptomatic ATTRv patients and 50 presymptomatic carriers) were consecutively enrolled. Fifty healthy volunteers were included as the control group. Ella™ apparatus was used to assess sNfL levels.

RESULTS

Serum NfL levels were increased in ATTRv patients compared to both presymptomatic carriers and healthy controls, whilst not differing between carriers and healthy controls. An sNfL cut-off of 37.10 pg/mL could discriminate between asymptomatic and symptomatic individuals with high diagnostic accuracy (area under the curve 0.958; p < 0.001), sensitivity (81.4%) and specificity (100%).

CONCLUSIONS

Serum NfL seems to be a promising biomarker of peripheral nerve involvement in ATTRv amyloidosis and might become a reliable, objective measure to detect the transition from the presymptomatic stage to the onset of symptomatic disease. Further longitudinal studies are needed to confirm such a role and determine whether it could equally represent a biomarker of disease progression and response to therapy.

Plasma Neurofilament Light Relates to Divergent Default and Salience Network Connectivity in Alzheimer's Disease and Behavioral Variant Frontotemporal Dementia

Background

Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) show differential vulnerability to large-scale brain functional networks. Plasma neurofilament light (NfL), a promising biomarker of neurodegeneration, has been linked in AD patients to glucose metabolism changes in AD-related regions. However, it is unknown whether plasma NfL would be similarly associated with disease-specific functional connectivity changes in AD and bvFTD.

Objective

Our study examined the associations between plasma NfL and functional connectivity of the default mode and salience networks in patients with AD and bvFTD.

Methods

Plasma NfL and neuroimaging data from patients with bvFTD (n = 16) and AD or mild cognitive impairment (n = 38; AD + MCI) were analyzed. Seed-based functional connectivity maps of key regions within the default mode and salience networks were obtained and associated with plasma NfL in these patients.

RESULTS

We demonstrated divergent associations between NfL and functional connectivity in AD + MCI and bvFTD patients. Specifically, AD + MCI patients showed lower default mode network functional connectivity with higher plasma NfL, while bvFTD patients showed lower salience network functional connectivity with higher plasma NfL. Further, lower NfL-related default mode network connectivity in AD + MCI patients was associated with lower Montreal Cognitive Assessment scores and higher Clinical Dementia Rating sum-of-boxes scores, although NfL-related salience network connectivity in bvFTD patients was not associated with Neuropsychiatric Inventory Questionnaire scores.

CONCLUSIONS

Our findings indicate that plasma NfL is differentially associated with brain functional connectivity changes in AD and bvFTD.

Plasma biomarkers for brain injury in extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a life-saving intervention for patients with refractory cardiorespiratory failure. Despite its benefits, ECMO carries a significant risk of neurological complications, including acute brain injury (ABI). Although standardized neuromonitoring and neurological care have been shown to improve early detection of ABI, the inability to perform neuroimaging in a timely manner is a major limitation in the accurate diagnosis of neurological complications. Therefore, blood-based biomarkers capable of detecting ongoing brain injury at the bedside are of great clinical significance. This review aims to provide a concise review of the current literature on plasma biomarkers for ABI in patients on ECMO support.

Maximizing the Clinical Value of Blood-Based Biomarkers for Mild Traumatic Brain Injury

Mild traumatic brain injury (TBI) and concussion can have serious consequences that develop over time with unpredictable levels of recovery. Millions of concussions occur yearly, and a substantial number result in lingering symptoms, loss of productivity, and lower quality of life. The diagnosis may not be made for multiple reasons, including due to patient hesitancy to undergo neuroimaging and inability of imaging to detect minimal damage. Biomarkers could fill this gap, but the time needed to send blood to a laboratory for analysis made this impractical until point-of-care measurement became available. A handheld blood test is now on the market for diagnosis of concussion based on the specific blood biomarkers glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl terminal hydrolase L1 (UCH-L1). This paper discusses rapid blood biomarker assessment for mild TBI and its implications in improving prediction of TBI course, avoiding repeated head trauma, and its potential role in assessing new therapeutic options. Although we focus on the Abbott i-STAT TBI plasma test because it is the first to be FDA-cleared, our discussion applies to any comparable test systems that may become available in the future. The difficulties in changing emergency department protocols to include new technology are addressed.

Use of 3D Printing Techniques to Fabricate Implantable Microelectrodes for Electrochemical Detection of Biomarkers in the Early Diagnosis of Cardiovascular and Neurodegenerative Diseases

This Review provides a comprehensive overview of 3D printing techniques to fabricate implantable microelectrodes for the electrochemical detection of biomarkers in the early diagnosis of cardiovascular and neurodegenerative diseases. Early diagnosis of these diseases is crucial to improving patient outcomes and reducing healthcare systems' burden. Biomarkers serve as measurable indicators of these diseases, and implantable microelectrodes offer a promising tool for their electrochemical detection. Here, we discuss various 3D printing techniques, including stereolithography (SLA), digital light processing (DLP), fused deposition modeling (FDM), selective laser sintering (SLS), and two-photon polymerization (2PP), highlighting their advantages and limitations in microelectrode fabrication. We also explore the materials used in constructing implantable microelectrodes, emphasizing their biocompatibility and biodegradation properties. The principles of electrochemical detection and the types of sensors utilized are examined, with a focus on their applications in detecting biomarkers for cardiovascular and neurodegenerative diseases. Finally, we address the current challenges and future perspectives in the field of 3D-printed implantable microelectrodes, emphasizing their potential for improving early diagnosis and personalized treatment strategies.

A trichotomy method for defining homogeneous subgroups in a dementia population

INTRODUCTION

Diagnosis of dementia in the aging brain is confounded by the presence of multiple pathologies. Mixed dementia (MX), a combination of Alzheimer's disease (AD) proteins with vascular disease (VD), is frequently found at autopsy, and has been difficult to diagnose during life. This report develops a method for separating the MX group and defining preclinical AD (presence of AD factors with normal cognition) and preclinical VD subgroups (presence of white matter damage with normal cognition).

METHODS

Clustering was based on three diagnostic axes: (1) AD factor (ADF) derived from cerebrospinal fluid proteins (Aβ42 and pTau), (2) VD factor (VDF) calculated from mean free water and peak width of skeletonized mean diffusivity in the white matter, and (3) Cognition (Cog) based on memory and executive function. The trichotomy method was applied to an Alzheimer's Disease Neuroimaging Initiative cohort (N = 538).

RESULTS

Eight biologically defined subgroups were identified which included the MX group with both high ADF and VDF (9.3%) and a preclinical VD group (3.9%), and a preclinical AD group (13.6%). Cog is significantly associated with both ADF and VDF, and the partial-correlation remains significant even when the effect of the other variable is removed (r(Cog, ADF/VDF removed) = 0.46, p < 10-28 and r(Cog, VDF/ADF removed) = 0.24, p < 10-7 ).

DISCUSSION

The trichotomy method creates eight biologically characterized patient groups, which includes MX, preclinical AD, and preclinical VD subgroups. Further longitudinal studies are needed to determine the utility of the 3-way clustering method with multimodal biological biomarkers.

Neuroprognostication value of serum neurofilament light chain for out-of-hospital cardiac arrest: A systematic review and meta-analysis

BACKGROUND

Neurofilament light chain (NfL) is a novel biomarker for the assessment of neurological function after cardiac arrest (CA). Although meta-analysis has confirmed its predictive value, it has not conducted a more detailed analysis of its research. We conducted a meta-analysis to evaluate the relationship between serum NfL level and neurological prognosis in patients with spontaneous circulation recovery after CA, and subgroup analysis was conducted according to sample collection time, time to assess neurological function, study design, whether TTM was received, the method of specimen determination, and the presence of neurological disease in patients. To analyze the influence of these factors on the predictive value of serum NfL.

METHODS

Published Cochrane reviews and an updated, extended search of MEDLINE, Cochrane Library, Embase, Scopus, ClinicalKey, CINAHL, and Web of Science for relevant studies until March 2022 were assessed through inclusion and exclusion criteria. The standard mean difference and 95% confidence interval were calculated using the random-effects model or fixed-effects model to assess the association between one variable factor NfL level and the outcome of CA patients. Subgroup analysis according to sample collection time was performed. The prognosis analysis and publication bias were also assessed using Egger's and Begg's tests.

RESULTS

Among 1209 related articles for screening, 6 studies (1360 patients) met the inclusion criteria and were selected for meta-analysis. The level of serum NfL in the good prognosis group (CPC1-2, CPC: cerebral performance category score) was significantly lower than that in the poor prognosis group (CPC3-5)SMD(standardized mean difference) = 0.553, 95%CI(confidence interval) = 0.418-0.687, I2 = 65.5% P<0.05). And this relationship also exists at each sampling time point (NfL specimens were collected on admission: SMD:0.48,95%CI:0.24-0.73; Samples were collected 24 hours after CA: SMD:0.60,95%CI:0.32-0.88;Specimens were obtained 48 hours after CA: SMD:0.51, 95%CI:0.18-0.85;Specimens were obtained 72 hours after CA: SMD:0.59, 95%CI:0.38-0.81).

CONCLUSION

NfL may play a potential neuroprognostication role in postcardiac arrest patients with spontaneous circulation, regardless of when the sample was collected after CA.

Paper-based lateral flow assay for the point-of-care detection of neurofilament light chain

Neurofilament light chain (NF-L) is a protein found in neurons of the nervous system and is widely used as a biomarker for neurological disorders. However, the current methods for detecting NF-L levels are complicated, expensive, and require specialized equipment, making it challenging to implement in a point-of-care (POC) setting. In this study, we developed a gold nanoshell (AuNS)-assisted lateral flow assay (LFA) based test strip for the POC detection of NF-L at a low ng/mL level (8 ng/mL = 117.65 pM). The test strip is a simple, rapid, and cost-effective method for detecting NF-L, making it suitable for use in a POC setting for the diagnosis and treatment of various neurological disorders. With its ease of use and reliability, the paper-based LFA is a valuable tool for the diagnosis and management of neurological conditions.Clinical Relevance- The AuNS-assisted LFA test strip developed in this study offers a rapid, cost-effective, and simple method for detecting NF-L levels, making it of great interest to practicing clinicians for the diagnosis of various neurological diseases such as HIV-associated dementia (HID), Amyotrophic Lateral Sclerosis (ALS), and Creutzfeldt-Jakob disease (CJD).

Urinary di-(2-ethylhexyl) phthalate metabolites are independently related to serum neurofilament light chain, a biomarker of neurological diseases, in adults: results from NHANES 2013-2014

Di (2-ethylhexyl) phthalate (DEHP) is a chemical commonly used in the manufacturing of plastics and can pose human health risks, including endocrine disruption, reproductive toxicity, and potential carcinogenic effects. Children may be particularly vulnerable to the harmful effects of DEHP. Early exposure to DEHP has been linked to potential behavioral and learning problems. However, there are no reports to date on whether DEHP exposure in adulthood has neurotoxic effects. Serum neurofilament light chain (NfL), a protein released into the blood after neuroaxonal damage, has been shown to be a reliable biomarker for many neurological diseases. To date, no study has examined the relationship between DEHP exposure and NfL. For the present study, we selected 619 adults (aged ≥ 20 years) from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) to examine the association between urinary DEHP metabolites and serum NfL. We reported higher urinary levels of ln-mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), ln-mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and ln-mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), and ln-ΣDEHP levels were associated with higher serum levels of ln-NfL (ΣDEHP: β-coefficient = 0. 075; S.E. = 0.026; P = 0.011). When we divided ΣDEHP into quartiles, mean NfL concentrations increased with quartiles of MEHHP (P for trend = 0.023). The association was more pronounced in males, non-Hispanic white race, higher income, and BMI < 25. In conclusion, higher DEHP exposure was positively associated with higher serum NfL in adults from NHANES 2013-2014. If this finding is causal, it is possible that DEHP exposure in adulthood may also induce neurological damage. Although the causality of this observation and the clinical significance are uncertain, our findings suggest that additional research is needed on DEHP exposure, serum NfL, and neurological disease in adults.

Review on the Role of Salivary Biomarkers in the Diagnosis of Mild Traumatic Brain Injury and Post-Concussion Syndrome

(1) Background: While mild traumatic brain injuries (TBIs) are a major public health issue, post-concussion syndrome (PCS) remains a controversial entity. In both cases, the clinical diagnosis is mainly based on the symptoms and brain imaging evaluation. The current molecular biomarkers were described from blood and cerebrospinal fluid (CSF), yet both fluid collection methods are invasive. Saliva could be preferred in molecular diagnosis due to its non-invasive and non-expensive methods of acquisition, transport, and samples processing. (2) Objectives: In the present study, we aimed to review the latest developments in salivary biomarkers and their potential role in diagnosing mild TBIs, and PCS. (3) Results: In TBIs and PCS, a few novel studies focusing on salivary biomarkers have emphasized their importance in diagnosis. The previous studies mainly focused on micro RNAs, and only a few on extracellular vesicles, neurofilament light chain, and S100B. (4) Conclusions: The combination between salivary biomarkers, clinical history and examination, self-reported symptoms, and cognitive/balance testing can provide a non-invasive alternative diagnostic methodology, as compared to the currently approved plasma and cerebrospinal fluid biomarkers.

Digital detection of proteins

This paper reviews methods for detecting proteins based on molecular digitization, i.e., the isolation and detection of single protein molecules or singulated ensembles of protein molecules. The single molecule resolution of these methods has resulted in significant improvements in the sensitivity of immunoassays beyond what was possible using traditional "analog" methods: the sensitivity of some digital immunoassays approach those of methods for measuring nucleic acids, such as the polymerase chain reaction (PCR). The greater sensitivity of digital protein detection has resulted in immuno-diagnostics with high potential societal impact, e.g., the early diagnosis and therapeutic intervention of Alzheimer's Disease. In this review, we will first provide the motivation for developing digital protein detection methods given the limitations in the sensitivity of analog methods. We will describe the paradigm shift catalyzed by single molecule detection, and will describe in detail one digital approach - which we call digital bead assays (DBA) - based on the capture and labeling of proteins on beads, identifying "on" and "off" beads, and quantification using Poisson statistics. DBA based on the single molecule array (Simoa) technology have sensitivities down to attomolar concentrations, equating to ∼10 proteins in a 200 μL sample. We will describe the concept behind DBA, the different single molecule labels used, the ways of analyzing beads (imaging of arrays and flow), the binding reagents and substrates used, and integration of these technologies into fully automated and miniaturized systems. We provide an overview of emerging approaches to digital protein detection, including those based on digital detection of nucleic acids labels, single nanoparticle detection, measurements using nanopores, and methods that exploit the kinetics of single molecule binding. We outline the initial impact of digital protein detection on clinical measurements, highlighting the importance of customized assay development and translational clinical research. We highlight the use of DBA in the measurement of neurological protein biomarkers in blood, and how these higher sensitivity methods are changing the diagnosis and treatment of neurological diseases. We conclude by summarizing the status of digital protein detection and suggest how the lab-on-a-chip community might drive future innovations in this field.

Serum neurofilament light chain in functionally relevant coronary artery disease and adverse cardiovascular outcomes

Background: Functionally relevant coronary artery disease (fCAD), causing symptoms of myocardial ischemia, can currently only be reliably detected with advanced cardiac imaging. Serum neurofilament light chain (sNfL) is a biomarker for neuro-axonal injury known to be elevated by cardiovascular (CV) risk factors and cerebrovascular small-vessel diseases. Due to their pathophysiological similarities with fCAD and the link to CV risk factors, we hypothesised that sNfL may have diagnostic and prognostic value for fCAD and adverse cardiovascular outcomes.Methods: Of the large prospective Basel VIII study (NCT01838148), 4'016 consecutive patients undergoing cardiac work-up for suspected fCAD were included (median age 68 years, 32.5% women, 46.9% with history of CAD). The presence of fCAD was adjudicated using myocardial perfusion imaging single-photon emission tomography (MPI-SPECT) and coronary angiography. sNfL was measured using a high-sensitive single-molecule array assay. All-cause and cardiovascular death, myocardial infarction (MI), and stroke/transient ischaemic attack (TIA) during 5-year follow-up were the prognostic endpoints.Results: The diagnostic accuracy of sNfL for fCAD as quantified by the area under the curve (AUC) was low (0.58, 95%CI 0.56-0.60). sNfL was strongly associated with age, renal dysfunction, and body mass index and was a strong and independent predictor of all-cause death, cardiovascular death, and stroke/TIA but not MI. Time-dependent AUC for cardiovascular-death at 1-year was 0.85, 95%CI 0.80-0.89, and 0.81, 95%CI 0.77-0.86 at 2-years.Conclusion: While sNfL concentrations did not show a diagnostic role for fCAD, in contrast, sNfL was a strong and independent predictor of cardiovascular outcomes, including all-cause death, cardiovascular death and stroke/TIA.

Plasma neurofilament light chain in memory clinic practice: Evidence from a real-life study

OBJECTIVE

To explore the accuracy of plasma neurofilament light chain (NfL) as a biomarker for diagnosis and staging of cognitive impairment, in a large cohort with of previously diagnosed patients in clinical practice.

METHODS

Retrospective, cross-sectional, monocentric study, from a tertiary memory clinic. Patients underwent cerebrospinal fluid core Alzheimer's disease (AD) biomarker evaluation using ELISA or Elecsys methods, and plasma NfL analysis using the single molecule array technology. The patients' biomarker data were examined for associations with: i/cognitive status ii/presence of neurodegenerative disease and iii/diagnostic groups. Associations between core CSF biomarkers and plasma NfL were determined.

RESULTS

Participants (N = 558, mean age = 69.2 ± 8.8, 56.5% women) were diagnosed with AD (n = 274, considering dementia and MCI stages), frontotemporal dementia (FTD, n = 55), Lewy body disease (LBD, n = 40, considering MCI and dementia stages), other neurodegenerative diseases, n = 57 (e.g Supranuclear Palsy, Corticobasal syndrome), non-neurodegenerative cognitive impairment (NND, n = 79, e.g. vascular lesions, epilepsy or psychiatric disorders) or subjective cognitive impairment (SCI, n = 53). Mean plasma NfL (log, pg/mL) levels were higher in neurodegenerative than non-neurodegenerative disorders (1.35 ± 0.2 vs 1.16 ± 0.23, p < 0.001), higher in all diagnostic groups than in SCI (1.06 ± 0.23) p < 0.001), and associated with the stage of cognitive impairment (p < 0.001). The addition of plasma NfL to a clinical model (age, MMSE and APOE ε4 carriership) marginally improved the discrimination of degenerative from non-degenerative disorders in ROC analysis (AUC clinical model: 0.81, 95% CI = [0.77;0.85] AUC clinical model + plasma NfL: AUC = 0.83 95% CI = [0.78;0.87], delta Akaike information criterion = -11.7).

DISCUSSION

Plasma NfL could help discrimination between degenerative and non-degenerative cognitive disorders, albeit not better than comprehensive clinical evaluation.

The trajectory of serum levels of glial fibrillary acidic protein within four weeks post-injury is related to neurological recovery during the transition from acute to chronic spinal cord injury

The use of biomarkers in spinal cord injury (SCI) research has evolved rapidly in recent years whereby most studies focused on the acute post-injury phase. Since SCI is characterized by persisting neurological impairments, the question arises whether blood biomarkers remain altered during the subacute post-injury time. Sample collection in the subacute phase might provide a better insight in the ongoing SCI specific molecular mechanism with fewer confounding factors compared to the acute phase where, amongst other complications, individuals receive a substantial amount of medication. This study aimed to determine if the temporal dynamics of serum biomarkers of neurodegeneration differ between individuals depending on their extent of neurological recovery in the transition phase between acute and chronic SCI. We performed a secondary analysis of biomarkers in patients with SCI (n=41) who were treated at a level I trauma center in Germany. Patients with cervical or thoracic SCI regardless of injury severity were included. Blood samples were collected in the acute phase (1-4 days post-injury), and after 30- and 120-days post-injury. Serum protein levels of Glial Fibrillary Acidic Protein (GFAP), and Neurofilament light protein (NfL) were determined for each time point of sample collection using R-Plex Assays (Meso Scale Discovery). Linear mixed models were used to evaluate the trajectory of GFAP and NfL over time. Fixed effects of time, neurological recovery, and injury severity along with the recovery-by-time interaction were included in models with random slopes and intercepts. GFAP levels increase during the first days after SCI and decrease in subacute to chronic stages. Notably, the trajectory of GFAP over time is significantly associated with the extent of neurological recovery during the transition from acute to chronic SCI with a steeper decline in individuals who recovered better. Serum levels of NfL continue to rise significantly until day 30 followed by a decrease afterwards, independent of neurological recovery. The trajectory of serum GFAP levels qualifies as a prognostic biomarker for neurological recovery, and facilitates monitoring of disease progression in the sub-acute post-injury phase.

Real-world applicability of glial fibrillary acidic protein and neurofilament light chain in Alzheimer's disease

Background: Blood-based biomarkers may add a great benefit in detecting the earliest neuropathological changes in patients with Alzheimer's disease (AD). We examined the utility of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) regarding clinical diagnosis and differentiation between amyloid positive and negative patients. To evaluate the practical application of these biomarkers in a routine clinical setting, we conducted this study in a heterogeneous memory-clinic population. Methods: We included 167 patients in this retrospective cross-sectional study, 123 patients with an objective cognitive decline [mild cognitive impairment (MCI) due to AD, n = 63, and AD-dementia, n = 60] and 44 age-matched healthy controls (HC). Cerebrospinal fluid (CSF) and plasma concentrations of NfL and GFAP were measured with single molecule array (SIMOA®) technology using the Neurology 2-Plex B kit from Quanterix. To assess the discriminatory potential of different biomarkers, age- and sex-adjusted receiver operating characteristic (ROC) curves were calculated and the area under the curve (AUC) of each model was compared. Results: We constructed a panel combining plasma NfL and GFAP with known AD risk factors (Combination panel: age+sex+APOE4+GFAP+NfL). With an AUC of 91.6% (95%CI = 0.85-0.98) for HC vs. AD and 81.7% (95%CI = 0.73-0.90) for HC vs. MCI as well as an AUC of 87.5% (95%CI = 0.73-0.96) in terms of predicting amyloid positivity, this panel showed a promising discriminatory power to differentiate these populations. Conclusion: The combination of plasma GFAP and NfL with well-established risk factors discerns amyloid positive from negative patients and could potentially be applied to identify patients who would benefit from a more invasive assessment of amyloid pathology. In the future, improved prediction of amyloid positivity with a noninvasive test may decrease the number and costs of a more invasive or expensive diagnostic approach.

Is liquid biopsy mature enough for the diagnosis of Alzheimer's disease?

The preclinical diagnosis and clinical practice for Alzheimer's disease (AD) based on liquid biopsy have made great progress in recent years. As liquid biopsy is a fast, low-cost, and easy way to get the phase of AD, continual efforts from intense multidisciplinary studies have been made to move the research tools to routine clinical diagnostics. On one hand, technological breakthroughs have brought new detection methods to the outputs of liquid biopsy to stratify AD cases, resulting in higher accuracy and efficiency of diagnosis. On the other hand, diversiform biofluid biomarkers derived from cerebrospinal fluid (CSF), blood, urine, Saliva, and exosome were screened out and biologically verified. As a result, more detailed knowledge about the molecular pathogenesis of AD was discovered and elucidated. However, to date, how to weigh the reports derived from liquid biopsy for preclinical AD diagnosis is an ongoing question. In this review, we briefly introduce liquid biopsy and the role it plays in research and clinical practice. Then, we summarize the established fluid-based assays of the current state for AD diagnostic such as ELISA, single-molecule array (Simoa), Immunoprecipitation-Mass Spectrometry (IP-MS), liquid chromatography-MS, immunomagnetic reduction (IMR), multimer detection system (MDS). In addition, we give an updated list of fluid biomarkers in the AD research field. Lastly, the current outstanding challenges and the feasibility to use a stand-alone biomarker in the joint diagnostic strategy are discussed.

Multidimensional overview of neurofilament light chain contribution to comprehensively understanding multiple sclerosis

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease characterized by demyelination, progressive axonal loss, and varying clinical presentations. Axonal damage associated with the inflammatory process causes neurofilaments, the major neuron structural proteins, to be released into the extracellular space, reaching the cerebrospinal fluid (CSF) and the peripheral blood. Methodological advances in neurofilaments’ serological detection and imaging technology, along with many clinical and therapeutic studies in the last years, have deepened our understanding of MS immunopathogenesis. This review examines the use of light chain neurofilaments (NFLs) as peripheral MS biomarkers in light of the current clinical and therapeutic evidence, MS immunopathology, and technological advances in diagnostic tools. It aims to highlight NFL multidimensional value as a reliable MS biomarker with a diagnostic-prognostic profile while improving our comprehension of inflammatory neurodegenerative processes, mainly RRMS, the most frequent clinical presentation of MS.

Neurological Involvement in COVID-19 Among Non-Hospitalized Adolescents and Young Adults

Introduction

Coronavirus disease 2019 (COVID-19) is prevalent among young people, and neurological involvement has been reported. We investigated neurological symptoms, cognitive test results, and biomarkers of brain injury, as well as associations between these variables in non-hospitalized adolescents and young adults with COVID-19.

Methods

This study reports baseline findings from an ongoing observational cohort study of COVID-19 cases and non-COVID controls aged 12–25 years (Clinical Trials ID: NCT04686734). Symptoms were charted using a standardized questionnaire. Cognitive performance was evaluated by applying tests of working memory, verbal learning, delayed recall, and recognition. The brain injury biomarkers, neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAp), were assayed in serum samples using ultrasensitive immunoassays.

Results

A total of 405 COVID-19 cases and 111 non-COVID cases were prospectively included. Serum Nfl and GFAp concentrations were significantly elevated in COVID-19 cases as compared with non-COVID controls (p = 0.050 and p = 0.014, respectively). The COVID-19 cases reported more fatigue (p < 0.001) and post-exertional malaise (PEM) (p = 0.001) compared to non-COVID-19 controls. Cognitive test performance and clinical neurological examination did not differ across the two groups. Within the COVID-19 group, there were no associations between symptoms, cognitive test results, and NfL or GFAp levels. However, fatigue and PEM were strongly associated with older age and female sex.

Conclusions

Non-hospitalized adolescents and young adults with COVID-19 reported more fatigue and PEM and had slightly elevated levels of brain injury markers, but showed normal cognitive performance. No associations were found between symptoms, brain injury markers, and cognitive test results, but fatigue and PEM were strongly related to female sex and older age.

A Method to Combine Neurofilament Light Measurements From Blood Serum and Plasma in Clinical and Population-Based Studies

Introduction

Neurofilament light (NfL) can be detected in blood of healthy individuals and at elevated levels in those with different neurological diseases. We investigated if the choice of biological matrix can affect results when using NfL as biomarker in epidemiological studies.

Method

We obtained paired serum and EDTA-plasma samples of 299 individuals aged 37–67 years (BiDirect study) and serum samples of 373 individuals aged 65–83 years (MEMO study). In BiDirect, Passing–Bablok analyses were performed to assess proportional and systematic differences between biological matrices. Associations between serum or EDTA-plasma NfL and renal function (serum creatinine, serum cystatin C, glomerular filtration rate, and kidney disease) were investigated using linear or logistic regression, respectively. All regression coefficients were estimated (1) per one ng/L increase and (2) per one standard deviation increase (standardization using z-scores). In MEMO, regression coefficients were estimated (1) per one ng/L increase of serum or calculated EDTA-plasma NfL and (2) per one standard deviation increase providing a comparison to the results from BiDirect.

Results

We found proportional and systematic differences between paired NfL measurements in BiDirect, i.e., serum NfL [ng/L] = −0.33 [ng/L] + 1.11 × EDTA-plasma NfL [ng/L]. Linear regression coefficients for the associations between NfL and renal function did not vary between the different NfL measurements. In MEMO, one standard deviation increase in serum NfL was associated with greater changes in the outcomes than in BiDirect.

Conclusion

Although there are differences between serum and EDTA-plasma NfL, results can be used interchangeably if standardized values are used.

Associations between neurofilament light-chain protein, brain structure, and chronic kidney disease

BACKGROUND

Neurofilament light-chain (NfL) protein is a blood-based marker of neuroaxonal injury. We sought to (1) compare plasma NfL levels in children with chronic kidney disease (CKD) and healthy peers, (2) characterize the relationship between NfL level and kidney function, and (3) evaluate NfL as a predictor of abnormal brain structure in CKD.

METHODS

Sixteen children with CKD due to congenital kidney anomalies and 23 typically developing peers were included. Plasma NfL was quantified using single-molecule array immunoassay. Participants underwent structural magnetic resonance imaging. Multiple linear regression models were used to evaluate the association between plasma NfL levels, kidney function, and brain structure.

RESULTS

An age × group interaction was identified whereby NfL levels increased with age in the CKD group only (estimate = 0.65; confidence interval (CI) = 0.08-1.22; p = 0.026). Decreased kidney function was associated with higher NfL levels (estimate = -0.10; CI = -0.16 to -0.04; p = 0.003). Lower cerebellar gray matter volume predicted increased plasma NfL levels (estimate = -0.00024; CI = -0.00039 to 0.00009; p = 0.004) within the CKD group.

CONCLUSIONS

Children with CKD show accelerated age-related increases in NfL levels. NfL level is associated with lower kidney function and abnormal brain structure in CKD.

IMPACT

NfL is a component of the neuronal cytoskeleton providing structural axonal support. Elevated NfL has been described in relation to gray and white matter brain volume loss. We have previously described the abnormal cerebellar gray matter in CKD. We explored the relationship between NfL, CKD, and brain volume. There is an accelerated, age-related increase in NfL level in CKD. Within the CKD sample, NfL level is associated with abnormal kidney function and brain structure. Decreased kidney function may be linked to abnormal neuronal integrity in pediatric CKD.

Towards a Better Understanding of the Atypical Features of Chronic Graft-Versus-Host Disease: A Report from the 2020 National Institutes of Health Consensus Project Task Force

Alloreactive and autoimmune responses after allogeneic hematopoietic cell transplantation can occur in non-classical chronic graft-versus-host disease (chronic GVHD) tissues and organ systems or manifest in atypical ways in classical organs commonly affected by chronic GVHD. The National Institutes of Health (NIH) consensus projects were developed to improve understanding and classification of the clinical features and diagnostic criteria for chronic GVHD. While still speculative whether atypical manifestations are entirely due to chronic GVHD, these manifestations remain poorly captured by the current NIH consensus project criteria. Examples include chronic GVHD impacting the hematopoietic system as immune mediated cytopenias, endothelial dysfunction, or as atypical features in the musculoskeletal system, central and peripheral nervous system, kidneys, and serous membranes. These purported chronic GVHD features may contribute significantly to patient morbidity and mortality. Most of the atypical chronic GVHD features have received little study, particularly within multi-institutional and prospective studies, limiting our understanding of their frequency, pathogenesis, and relation to chronic GVHD. This NIH consensus project task force report provides an update on what is known and not known about the atypical manifestations of chronic GVHD, while outlining a research framework for future studies to be undertaken within the next three to seven years. We also provide provisional diagnostic criteria for each atypical manifestation, along with practical investigation strategies for clinicians managing patients with atypical chronic GVHD features.

Plasma neurofilament light chain levels are associated with depressive and anxiety symptoms in Parkinson's disease

The present study aimed to explore the association of plasma neurofilament light chain (NfL) levels with depression and anxiety in Parkinson's disease (PD). This prospective study enrolled 116 patients with PD and 38 healthy controls, and found plasma NfL levels were higher in patients with depression or anxiety than in those without these symptoms. Binary logistic regression identified NfL concentration as an independent predictor of depression and anxiety in PD. In conclusion, elevated plasma NfL may be associated with severity of depression and anxiety in PD patients and may serve as a diagnostic biomarker of PD with moderate to severe depression or anxiety.

The Role of Tau beyond Alzheimer’s Disease: A Narrative Review

Nowadays, there is a need for reliable fluid biomarkers to improve differential diagnosis, prognosis, and the prediction of treatment response, particularly in the management of neurogenerative diseases that display an extreme variability in clinical phenotypes. In recent years, Tau protein has been progressively recognized as a valuable neuronal biomarker in several neurological conditions, not only Alzheimer’s disease (AD). Cerebrospinal fluid and serum Tau have been extensively investigated in several neurodegenerative disorders, from classically defined proteinopathy, e.g., amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Parkinson’s disease (PD), but also in inflammatory conditions such as multiple sclerosis (MS), as a marker of axonal damage. In MS, total Tau (t-Tau) may represent, along with other proteins, a marker with diagnostic and prognostic value. In ALS, t-Tau and, mainly, the phosphorylated-Tau/t-Tau ratio alone or integrated with transactive DNA binding protein of ~43 kDa (TDP-43), may represent a tool for both diagnosis and differential diagnosis of other motoneuron diseases or tauopathies. Evidence indicated the crucial role of the Tau protein in the pathogenesis of PD and other parkinsonian disorders. This narrative review summarizes current knowledge regarding non-AD neurodegenerative diseases and the Tau protein.

Prediction of good neurological outcome in comatose survivors of cardiac arrest: a systematic review

PURPOSE

To assess the ability of clinical examination, blood biomarkers, electrophysiology or neuroimaging assessed within 7 days from return of spontaneous circulation (ROSC) to predict good neurological outcome, defined as no, mild, or moderate disability (CPC 1-2 or mRS 0-3) at discharge from intensive care unit or later, in comatose adult survivors from cardiac arrest (CA).

METHODS

PubMed, EMBASE, Web of Science and the Cochrane Database of Systematic Reviews were searched. Sensitivity and specificity for good outcome were calculated for each predictor. The risk of bias was assessed using the QUIPS tool.

RESULTS

A total of 37 studies were included. Due to heterogeneities in recording times, predictor thresholds, and definition of some predictors, meta-analysis was not performed. A withdrawal or localisation motor response to pain immediately or at 72-96 h after ROSC, normal blood values of neuron-specific enolase (NSE) at 24 h-72 h after ROSC, a short-latency somatosensory evoked potentials (SSEPs) N20 wave amplitude > 4 µV or a continuous background without discharges on electroencephalogram (EEG) within 72 h from ROSC, and absent diffusion restriction in the cortex or deep grey matter on MRI on days 2-7 after ROSC predicted good neurological outcome with more than 80% specificity and a sensitivity above 40% in most studies. Most studies had moderate or high risk of bias.

CONCLUSIONS

In comatose cardiac arrest survivors, clinical, biomarker, electrophysiology, and imaging studies identified patients destined to a good neurological outcome with high specificity within the first week after cardiac arrest (CA).

Neurofilaments light: Possible biomarker of brain modifications in bipolar disorder

INTRODUCTION

Brain white matter (WM) abnormalities are biomarkers that seem to be involved in bipolar disorder (BD) aetiology and maintenance. Evidences suggest a possible association between neurodegeneration, neuroaxonal alterations and BD. A biomarker that is recently drawing attention is neurofilaments light (NfL) chain, a cytoskeletal intermediate filament protein expressed in neurons. To investigate neuroimaging alterations associated with BD, we studied the association between NfL levels and WM microstructure.

METHODS

NfL plasma quantification was performed in a sample of 45 depressed BD patients compared with 29 healthy controls (HC) using Quanterix SIMOA assay. Statistical analysis were conducted to evaluate NfL levels differences between BD patients and controls. Analyses of the diffusion data were performed using Tract Based Spatial Statistics (TBSS) on Diffusion Tensor images acquired using a 3.0 Tesla MR scanner.

RESULTS

Patients had higher NfL levels than HC (9.13 ± 4.78 vs 4.28 ± 2.39 pg/ml; p < 0.001). The separate-slopes analysis of variance showed a significant interaction of age with diagnosis (Likelihood-ratio test: χ2 = 27.52, p < 0.0001) with significant effects only in the BD sample (p = 0.023). The TBSS analysis, performed within the BD sample, showed a significant positive correlation between NfL levels and axial diffusivity (AD) in a wide single cluster encompassing several tracts.

DISCUSSION

Our results suggest that the physiological age-dependent increment of NfL level is augmented in BD, possibly because of increased remodelling and plasticity processes related to an accelerated ageing condition. The positive association between NfL levels and AD, may reflect a condition of remyelination and axonal regeneration.

Plasma neurofilament light, glial fibrillary acidic protein and lysosphingolipid biomarkers for pharmacodynamics and disease monitoring of GM2 and GM1 gangliosidoses patients

GM2 and GM1 gangliosidoses are genetic, neurodegenerative lysosomal sphingolipid storage disorders. The earlier the age of onset, the more severe the clinical presentation and progression, with infantile, juvenile and late-onset presentations broadly delineated into separate phenotypic subtypes. Gene and substrate reduction therapies, both of which act directly on sphingolipidosis are entering clinical trials for treatment of these disorders. Simple to use biomarkers for disease monitoring are urgently required to support and expedite these clinical trials. Here, lysosphingolipid and protein biomarkers of sphingolipidosis and neuropathology respectively, were assessed in plasma samples from 33 GM2 gangliosidosis patients, 13 GM1 gangliosidosis patients, and compared to 66 controls. LysoGM2 and lysoGM1 were detectable in 31/33 GM2 gangliosidosis and 12/13 GM1 gangliosidosis patient samples respectively, but not in any controls. Levels of the axonal damage marker Neurofilament light (NF-L) were highly elevated in both GM2 and GM1 gangliosidosis patient plasma samples, with no overlap with controls. Levels of the astrocytosis biomarker Glial fibrillary acidic protein (GFAP) were also elevated in samples from both patient populations, albeit with some overlap with controls. In GM2 gangliosidosis patient plasma NF-L, Tau, GFAP and lysoGM2 were all most highly elevated in infantile onset patients, indicating a relationship to severity and phenotype. Plasma NF-L and liver lysoGM2 were also elevated in a GM2 gangliosidosis mouse model, and were lowered by treatment with a drug that slowed disease progression. These results indicate that lysosphingolipids and NF-L/GFAP have potential to monitor pharmacodynamics and pathogenic processes respectively in GM2 and GM1 gangliosidoses patients.

High or increasing serum NfL is predictive of impending multiple sclerosis relapses

BACKGROUND

One-off serum levels of neurofilament light chain (sNfL) is an established predictor of emerging disease activity in multiple sclerosis (MS). However, the importance of longitudinal increases in sNfL is yet to be enumerated, an important consideration as this test is translated for serial monitoring. Glial Fibrillary Acidic Protein (sGFAP) is another biomarker of predictive interest. Our objective was to assess the association between longitudinal changes sNfL and prediction of future relapses, as well as a possible role for sGFAP.

METHODS

Participants with active MS were prospectively monitored for one year as part of a clinical trial testing mesenchymal stem cells. Visits every three months or less included clinical assessments, MRI scans and serum draws. sNfL and sGFAP concentrations were quantified with Single Molecule Array immunoassay. We used Kaplan-Meier estimates and Anderson-Gill Cox regression models with and without adjustment for age, sex, disease subtype, disease duration and expanded disability status score (EDSS) to estimate the rate of relapse predicted by baseline and longitudinal changes in biomarker.

RESULTS

58 Canadian and Italian participants with MS were enrolled in this study. Higher baseline sNfL was future relapse (Log-rank p = 0.0068), MRI lesions (p=0.0096), composite-relapse associated worsening (p=0.01) and progression independent of relapse activity (p=0.0096). Conversely, baseline sGFAP was only weakly associated with MRI lesions (0.044). Cross-sectional analyses of baseline sNfL revealed that a two-fold difference in baseline sNfL, e.g. from 10 to 20 pg/mL, was associated with a 2.3-fold increased risk of relapse during follow-up (95% confidence interval 1.65-3.17). Longitudinally, a two-fold increase in sNfL level from the first measurement was associated with an additional 1.46 times increased risk of relapse (1.07-2.00). The impact of longitudinal increases in sNfL on the risk of relapse were most pronounced for patients with lower baseline values of sNfL (<10 pg/mL: HR = 1.54, 1.06-2.24). These associations remained significant after adjustment for potential confounders.

CONCLUSION

We enumerate the risk of relapse associated with dynamic changes in sNfL. Both baseline and longitudinal change in sNfL may help identify patients who would benefit from early treatment optimisation.

TRIAL REGISTRATIONS

Canada:NCT02239393, Italy:NCT01854957&EudraCT, 2011-001295-19 CLASSIFICATION OF EVIDENCE: This study provides class 1 evidence that high baseline and longitudinal increases in sNfL are predictive of impending relapses in patients with active MS.

The Two Sides of Siponimod: Evidence for Brain and Immune Mechanisms in Multiple Sclerosis

Siponimod is a selective sphingosine 1-phosphate receptor subtype 1 (S1P₁) and 5 (S1P₅) modulator approved in the United States and the European Union as an oral treatment for adults with relapsing forms of multiple sclerosis (RMS), including active secondary progressive multiple sclerosis (SPMS). Preclinical and clinical studies provide support for a dual mechanism of action of siponimod, targeting peripherally mediated inflammation and exerting direct central effects. As an S1P₁ receptor modulator, siponimod reduces lymphocyte egress from lymph nodes, thus inhibiting their migration from the periphery to the central nervous system. As a result of its peripheral immunomodulatory effects, siponimod reduces both magnetic resonance imaging (MRI) lesion (gadolinium-enhancing and new/enlarging T2 hyperintense) and relapse activity compared with placebo. Independent of these effects, siponimod can penetrate the blood-brain barrier and, by binding to S1P₁ and S1P₅ receptors on a variety of brain cells, including astrocytes, oligodendrocytes, neurons, and microglia, exert effects to modulate neural inflammation and neurodegeneration. Clinical data in patients with SPMS have shown that, compared with placebo, siponimod treatment is associated with reductions in levels of neurofilament light chain (a marker of neuroaxonal damage) and thalamic and cortical gray matter atrophy, with smaller reductions in MRI magnetization transfer ratio and reduced confirmed disability progression. This review examines the preclinical and clinical data supporting the dual mechanism of action of siponimod in RMS.