Serum neurofilament light levels in normal aging and their association with morphologic brain changes

Insights into spinal muscular atrophy from molecular biomarkers

Spinal muscular atrophy is a devastating motor neuron disease characterized by severe cases of fatal muscle weakness. It is one of the most common genetic causes of mortality among infants aged less than 2 years. Biomarker research is currently receiving more attention, and new candidate biomarkers are constantly being discovered. This review initially discusses the evaluation methods commonly used in clinical practice while briefly outlining their respective pros and cons. We also describe recent advancements in research and the clinical significance of molecular biomarkers for spinal muscular atrophy, which are classified as either specific or non-specific biomarkers. This review provides new insights into the pathogenesis of spinal muscular atrophy, the mechanism of biomarkers in response to drug-modified therapies, the selection of biomarker candidates, and would promote the development of future research. Furthermore, the successful utilization of biomarkers may facilitate the implementation of gene-targeting treatments for patients with spinal muscular atrophy.

Longitudinal Plasma Biomarker Profiles Predict Neurological Outcome in Traumatic Spinal Cord Injury

OBJECTIVE

Traumatic spinal cord injury (SCI) is diagnosed by imaging and clinical scoring using the American Spinal Injury Association Impairment Scale (AIS). These methods have limited value for prognosis. Here, the prognostic value of plasma neurofilament-light (NfL), glial fibrillary acidic protein (GFAP), and contactin-1 (CNTN-1) was analyzed.

METHODS

Biomarker levels were determined in the plasma of traumatic SCI patients (n = 37) and healthy controls (n = 22). SCI samples (n = 112) were collected at different time points from 0 to 4 days to 18 weeks post-injury. NfL and GFAP were measured by single molecule array (Simoa) technology, CNTN-1 by Luminex. Baseline and outcome AIS and motor scores were collected as a measure of injury severity.

RESULTS

NfL, GFAP, and CNTN-1 showed different kinetics in SCI patients over time. Baseline biomarker levels could identify AIS-A SCI patients (NfL + GFAP) and discriminate between patients with a motor score change <5 and those with a change ≥5 (NfL + GFAP+CNTN-1). Longitudinally, NfL could identify AIS-A patients up to 12 weeks post-SCI and discriminate between patients with a motor score change <5 and those with a change ≥5 up to 18 weeks post-SCI. Further, baseline biomarker levels positively (NfL + GFAP) or negatively (CNTN-1) correlated with outcome injury severity and together could accurately predict AIS conversion (AUC 0.863) and motor score change (AUC 0.857). This predictive ability was maintained in subacute/chronic SCI stages.

INTERPRETATION

In conclusion, plasma NfL, GFAP, and CNTN-1 are potential prognostic biomarkers in SCI. This is important for patient stratification in clinical trials, prediction of neurological outcome and informed decision-making in SCI treatment and rehabilitation. ANN NEUROL 2025;97:1180-1189.

Biomarkers of Progression Independent of Relapse Activity-Can We Actually Measure It Yet?

Progression independent of relapse activity (PIRA) is increasingly recognized as a key driver of disability in multiple sclerosis (MS). However, the concept of PIRA remains elusive, with uncertainty surrounding its definition, underlying mechanisms, and methods of quantification. This review examines the current landscape of biomarkers used to predict and measure PIRA, focusing on clinical, imaging, and body fluid biomarkers. Clinical disability scores such as the Expanded Disability Status Scale (EDSS) are widely used, but may lack sensitivity in capturing subtle relapse-independent progression. Imaging biomarkers, including MRI-derived metrics (brain and spinal cord volume loss, chronic active lesions) and optical coherence tomography (OCT) parameters (retinal nerve fiber layer and ganglion cell-inner plexiform layer thinning), offer valuable insights, but often reflect both inflammatory and neurodegenerative processes. Body fluid biomarkers, such as neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP), are promising indicators of axonal damage and glial activation, but their specificity for PIRA remains limited. This review emphasizes the distinction between predicting PIRA-identifying individuals at risk of future progression-and measuring ongoing PIRA-related disability in real time. We highlight the limitations of current biomarkers in differentiating PIRA from relapse-associated activity and call for a clearer conceptual framework to guide future research. Advancing the precision and utility of PIRA biomarkers will require multimodal approaches, longitudinal studies, and standardized protocols to enable their clinical integration and to improve personalized MS management.

Serum glial fibrillary protein reflects early brain injury dynamics and cognitive changes after deep brain stimulation surgery

Deep brain stimulation (DBS) is an efficient treatment for movement disorders, most commonly Parkinson's Disease (PD), dystonia and essential tremor. DBS surgery carries risks, e.g. the risk of delayed peri-lead edema (PLE) and the risk of postoperative cognitive decline. The mechanisms of these complications are not fully understood and there is no established biomarker to screen for these complications after DBS surgery. To explore the diagnostic value of two blood-based markers representative for distinct types of brain injury, we characterized the dynamics of serum glial fibrillary acidic protein (sGFAP, for glial injury) and serum neurofilament light chain (sNfL, for neuronal-axonal injury) following DBS surgery. We analyzed longitudinal dynamics of serum protein levels in 58 patients undergoing deep brain stimulation (DBS) at our center for half a year post-surgery. Serum GFAP responded much more rapidly after brain surgery, returning to baseline after weeks, whereas sNfL only returned to baseline after months. Patients with lower preoperative cognitive performance exhibited higher postoperative sGFAP levels, with sGFAP showing a stronger association with preoperative patient characteristics compared to sNfL. Further studies with long-term clinical follow-up are needed to fully evaluate the utility of sGFAP as a biomarker for both early and delayed complications after DBS surgery, including cognitive decline and potential foreign body reactions to the implanted lead.

Association of Nonmodifiable Risk Factors With Alzheimer Disease Blood Biomarkers in Community-Dwelling Adults in the ESTHER Study

BACKGROUND AND OBJECTIVES

Dementia-related blood biomarkers are the future of large-scale dementia risk stratification; however, the extent to which phosphorylated tau (P-tau181), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP) are associated with nonmodifiable risk factors has yet to be confirmed in the community, and the role of menopause has yet to be investigated. Therefore, the aim of this study was to examine the association of age, sex, APOEe4 status, and menopause, with dementia-related blood biomarker levels (P-tau181, NfL, and GFAP) and rate of change over 11 years in longitudinal biomarker measurements in community-dwelling adults.

METHODS

Within this German population-based Epidemiologische Studie zu Chancen der Verhütung, Früherkennung und optimierten Therapie chronischer Erkrankungen in der älteren Bevölkerung cohort study (n = 9,940), a nested case-control study of 1,026 participants (1:1, without dementia during follow-up: incident dementia during follow-up) aged 50-75 years at baseline followed over 17 years was conducted. Blood biomarker measurements (P-tau181, NfL, and GFAP) were completed in blood from baseline, 8-year, and 11-year follow-ups, and cross-sectional and longitudinal regression analyses were used to assess the association with age, sex, APOEe4, and menopause.

RESULTS

The mean age of participants was 64 years, and women accounted for slightly over half (54%) of the sample. Age was cross-sectionally and longitudinally significantly associated with all dementia-related biomarkers (p < 0.001). NfL and GFAP levels more strongly correlated (Spearman R = 0.55 and 0.49) with age at baseline than P-tau181 levels (Spearman R = 0.21). Women experienced significantly higher levels and rates of increase in GFAP (p < 0.001) while men experienced higher levels of NfL after adjusting for age and APOEe4 (p < 0.01). APOEe4 status was significantly associated with baseline and longitudinal levels of P-tau181 (baseline β = 0.30, p < 0.05) and GFAP (baseline β = 15.84, p < 0.001). Of interest, premenopausal status was significantly associated with higher GFAP levels after adjusting for age, sex, and APOEe4 (β = 19.09, p < 0.05).

DISCUSSION

This population-based study on dementia biomarkers found that P-tau181 was dependent on age and APOEe4; NfL on age and sex; and GFAP on age, sex, APOEe4, and menopause status. GFAP levels and rate of increase were higher in women, especially in premenopausal participants. Future research should confirm these findings and further explore the role of menopause in dementia pathogenesis among women.

Association of Peak Width of Skeletonized Mean Diffusivity With Neurofilament Light Chain in Non-Dementia Adults

Peak width of skeletonized mean diffusivity (PSMD) effectively reflects the mean diffusivity distribution across the white matter and is considered a novel biomarker for cerebral small vessel disease (CSVD). Neurofilament light chain (NFL) is observed to be released in neurodegenerative diseases with large myelinated axonal degeneration. In our research, we explored the relationship of PSMD with NFL levels in non-dementia adults. In the Alzheimer's Disease Neuroimaging Initiative, after adjusting for potential confounders, we used linear regression models to study the relationship of PSMD with plasma NFL levels in the total population and different white matter brain regions. Additionally, we analyzed the relationships in subgroups. Furthermore, we used a linear mixed effects model to assess the long-term effect of baseline PSMD on longitudinal changes in plasma NFL levels. The results showed that PSMD was correlated with elevated plasma NFL levels in the total population, with significant associations observed in late-life, APOE4 non-carriers, and A- (amyloid-negative) subgroups. Further analysis of different white matter brain regions revealed a correlation in the body of the corpus callosum, superior corona radiata, posterior thalamic radiation, sagittal stratum, fornix/stria terminalis, and superior fronto-occipital fasciculus. Moreover, individuals with higher PSMD demonstrated a faster increase in plasma NFL levels in the total population, which was significant in the late-life and A- subgroups. This study demonstrated that PSMD was associated with plasma NFL, suggesting that CSVD was related to neurodegenerative disorders, particularly in the body of the corpus callosum, superior corona radiata, posterior thalamic radiation, sagittal stratum, fornix/stria terminalis, and superior fronto-occipital fasciculus. At the same time, PSMD would exacerbate the damage to plasma NFL levels. These findings support the idea that plasma NFL may be a promising biomarker for CSVD.

Plasma Glial Fibrillary Acidic Protein and Neurofilament Light Are Elevated in Bipolar Depression: Evidence for Neuroprogression and Astrogliosis

BACKGROUND

Recent advances now allow detection of brain-specific proteins in blood, including neurofilament light chain (NfL), a marker of axonal pathology, and glial fibrillary acidic protein (GFAP), indicative of astrocytic activation. Given the evidence of astroglial pathology and neuronal dysfunction in bipolar disorder, and ongoing debates on neuroprogression, we investigated plasma NfL and GFAP levels in affected individuals.

METHODS

This study analysed plasma NfL and GFAP measured in 216 individuals using Simoa. We used bootstrapped general linear models (GLM) to compare plasma NfL and GFAP levels between people with bipolar depression (n = 120) and healthy controls (n = 96), adjusting for age, sex, and weight. We examined associations between these biomarkers and clinical variables while adjusting for multiple comparisons. For sensitivity analyses, predictors were evaluated using Bayesian model averaging (BMA).

RESULTS

Plasma GFAP (β = 0.21 [0.07, 0.35], p = 0.006) and NfL (β = 0.06 [0.01, 0.10], p = 0.028) were elevated in people with bipolar depression. Illness duration was positively associated with NfL (r = 2.97, p = 0.002), and further supported by BMA analysis (posterior inclusion probability, PIP = 0.85). Age of onset was positively associated with GFAP (r = 0.246 p = 0.041), which was also supported by BMA analysis (PIP = 0.67).

CONCLUSIONS

These findings indicate increased plasma NfL and GFAP levels in bipolar disorder. Our findings support the neuroprogression hypothesis, where prolonged illness duration contributes to neuroaxonal damage. Elevated GFAP in those with later onset suggests a role for neuroinflammation, potentially linked to increased cardiovascular and metabolic comorbidities.

Biomarker and cognitive decline in atrial fibrillation: a prospective cohort study

We investigated associations of a broad biomarker panel with cognitive decline in atrial fibrillation (AF) patients to characterize possible mechanisms. We enrolled 1440 AF patients with available baseline biomarkers and cognitive testing by the Montreal Cognitive assessment (MoCA) score at inclusion and at ≥ 2 yearly follow-ups. We investigated the associations of biomarkers with cognitive decline in univariate logistic regression models, LASSO regression analysis and built a combined model. Mean age was 72 years, 75% male, 47% paroxysmal AF. Over 4 years, 93 patients (6.5%) had cognitive decline. These patients had more often permanent AF (32.3 vs 21.5%, p = 0.007) and more often a history stroke (23.7 vs 11.2%, p < 0.001), but similar baseline MoCA scores (24.9 vs 25.3 points, p = 0.22) and anticoagulation rates (93.5 vs 89.5%, p = 0.29). The three biomarkers with the highest univariate AUC for cognitive decline were GDF-15 (0.67 [0.62-0.72]), Cystatin C (0.67 [0.61-0.72]) and high-sensitivity Troponin T (hs-TnT) (0.65 [0.60-0.70]). In LASSO regression analysis, the best cross validation included GDF-15, GFAP, ESM-1, NfL and ALAT. The combined prediction model with the highest AUC of 0.73 (0.68-0.78) included IGFBP-7, GDF-15, Cystatin C, hsCRP, ALAT, GFAP, ESM-1 and FGF23. Over 4 years, 6.5% of AF patients had cognitive decline despite a high rate of anticoagulation. Inflammation, neuronal damage, and increased amyloid-beta might be important non-ischemic mechanisms of cognitive decline in AF patients.

Association between serum neurofilament light chain levels and grip strength among US adults: a cross-sectional study using National Health and Nutrition Examination Survey data from 2013 to 2014

OBJECTIVE

We aimed to investigate the relationship between serum neurofilament light chain (NfL) and grip strength using data from the 2013-2014 US National Health and Nutrition Examination Survey (NHANES).

DESIGN

Secondary analysis of cross-sectional, population-based data.

SETTING

NHANES sample, 2013-2014.

PARTICIPANTS

We studied 1925 participants aged 20-75 years.

OUTCOME MEASURES AND ANALYSIS

We applied a multivariable generalised linear regression model, adjusted for several potential confounders, and restrictive cubic spline models to evaluate the association between serum NfL and grip strength. Subgroup analyses were conducted using stratified multivariable linear regression analysis.

RESULTS

We included 1925 participants (average age: 44.8±0.44 years) from the NHANES database. Participants with higher serum NfL levels had a significantly higher prevalence of medical conditions (hypertension, diabetes, cardiovascular disorder, chronic kidney disease (CKD) and cancer) compared with those with lower NfL levels (all p<0.001). After adjusting for confounding factors, there was a negative association between serum NfL and grip strength (β=-2.07; 95% CI -3.47, -0.67; p=0.007). In addition, significant interactions were found between NfL and grip strength stratified by age, physical activity and CKD (p value for interaction=0.002, 0.023 and 0.006). The results of the restricted cubic splines (RCS) analysis showed no evidence against a linear association of serum NfL levels with grip strength. (p for non-linearity=0.334).

CONCLUSION

Our study demonstrates a strong, negative and linear correlation between elevated serum NfL levels and grip strength. Notably, our findings indicate that individuals aged between 60 and 75 years, those with physical inactivity and those with CKD exhibit a more pronounced reduction in grip strength with increasing serum NfL levels.

Sleep abnormalities are associated with greater cognitive deficits and disease activity in Huntington's disease: a 12-year polysomnographic study

Increasing evidence suggests that the sleep pathology associated with neurodegenerative diseases can in turn exacerbate both the cognitive deficits and underlying pathobiology of these conditions. Treating sleep may therefore bear significant, even disease-modifying, potential for these conditions, but how best and when to do so remains undetermined. Huntington's disease, by virtue of being an autosomal dominant neurodegenerative disease presenting in mid-life, presents a key 'model' condition through which to advance this field. To date, however, there has been no clinical longitudinal study of sleep abnormalities in Huntington's disease and no robust interrogation of their association with disease onset, cognitive deficits and markers of disease activity. Here, we present the first such study. Huntington's disease gene carriers (n = 28) and age- and sex-matched controls (n = 21) were studied at baseline and 10- and 12-year follow-up. All Huntington's disease gene carriers were premanifest at baseline and were stratified at follow-up into 'prodromal/manifest' versus 'premanifest' groups. Objective sleep abnormalities were assessed through two-night inpatient polysomnography and 2-week domiciliary actigraphy, and their association was explored against Montreal Cognitive Assessment, Trail A/B task, Symbol Digit Modalities Task (SDMT), Hopkins Verbal Learning Task (HVLT) and Montgomery-Asberg Depression Rating Scale (MADRS) scores, plus serum neurofilament light levels. Statistical analysis incorporated cross-sectional ANOVA, longitudinal repeated measures linear models and regressions adjusted for multiple confounders including disease stage. Fifteen Huntington's disease gene carriers phenoconverted to prodromal/early manifest Huntington's disease by study completion. At follow-up, these gene carriers showed more frequent sleep stage changes (P ≤ 0.001, ηp 2 = 0.62) and higher levels of sleep maintenance insomnia (defined by wake after sleep onset, P = 0.002, ηp 2 = 0.52). The latter finding was corroborated by nocturnal motor activity patterns on follow-up actigraphy (P = 0.004, ηp 2 = 0.32). Greater sleep maintenance insomnia was associated with greater cognitive deficits (Trail A P ≤ 0.001, R 2 = 0.78; SDMT P = 0.008, R 2 = 0.63; Trail B P = 0.013, R 2 = 0.60) and higher levels of neurofilament light (P = 0.015, R 2 = 0.39). Longitudinal modelling suggested that sleep stage instability accrues from the early premanifest phase, whereas sleep maintenance insomnia emerges closer to phenoconversion. Baseline sleep stage instability was able to discriminate those who phenoconverted within the study period from those who remained premanifest (area under curve = 0.81, P = 0.024). These results demonstrate that the key sleep abnormalities of premanifest/early Huntington's disease are sleep stage instability and sleep maintenance insomnia and suggest that the former bears value in predicting disease onset, while the latter is associated with greater disease activity and cognitive deficits. Intervention studies to interrogate causation within this association could not only benefit patients with Huntington's disease but also help provide fundamental proof-of-concept findings for the wider sleep-neurodegeneration field.

Blood biomarkers of neuronal injury and astrocytic reactivity in electroconvulsive therapy

Despite electroconvulsive therapy (ECT) being recognized as an effective treatment for major depressive episodes (MDE), its application is subject to controversy due to concerns over cognitive side effects. The pathophysiology of these side effects is not well understood. Here, we examined the effects of ECT on blood-based biomarkers of neuronal injury and astrocytic reactivity. Participants with a major depressive episode (N = 99) underwent acute ECT. Blood was sampled just before (T0) and 30 min after (T1) the first ECT session, as well as just before the sixth session (T2; 48-72 h after the fifth session). Age- and sex-matched controls (N = 99) were recruited from the general population. Serum concentrations of neurofilament light chain (NfL), total tau protein, and glial fibrillary acidic protein (GFAP) were measured with ultrasensitive single-molecule array assays. Utilizing generalized least squares regression, we compared baseline (T0) biomarker concentrations against those of our control group, and calculated the shifts in serum biomarker concentrations from baseline to immediately post-first ECT session (T1), and prior to the sixth session (T2). Baseline analysis revealed that serum levels of NfL (p < 0.001) and tau (p = 0.036) were significantly elevated in ECT recipients compared with controls, whereas GFAP levels showed no significant difference. Relative to T0, serum NfL concentration neither changed at T1 (mean change 3.1%, 95%CI -0.5% to 6.7%, p = 0.088) nor at T2 (mean change -3.2%, 95%CI -7.6% to 1.5%, p = 0.18). Similarly, no change in total tau was observed (mean change 3.7%, 95%CI -11.6% to 21.7%, p = 0.65). GFAP increased from T0 to T1 (mean change 20.3%, 95%CI 14.6 to 26.3%, p < 0.001), but not from T0 to T2 (mean change -0.7%, 95%CI -5.8% to 4.8%, p = 0.82). In conclusion, our findings suggest that ECT induces a temporary increase in serum GFAP, possibly reflecting transient astrocytic activation. Importantly, we observed no indicators of neuronal damage or long-term elevation in any assessed biomarker.

ALS plasma biomarkers reveal neurofilament and pTau correlate with disease onset and progression

OBJECTIVE

We performed a pilot screen to assess the utility of the NULISA™ (Nucleic-acid-Linked Immuno-Sandwich Assay) platform in the identification of amyotrophic lateral sclerosis (ALS) biomarkers.

METHODS

Plasma from 86 individuals (48 ALS, 18 asymptomatic C9orf72 repeat expansion carriers (AsymC9), and 20 healthy controls) was analyzed via a multiplexed NULISA™ assay that includes 120 neurodegeneration-associated proteins. Statistical analysis of NULISA™ results was performed to identify proteins differentially expressed in plasma and their correlation with disease-associated parameters.

RESULTS

ALS plasma showed elevation of the established biomarkers, neurofilament light chain (NEFL) and neurofilament heavy chain (NEFH). Compared to controls and AsymC9, microtubule-associated protein tau (MAPT), phosphorylated tau 181 (pTau181), phosphorylated tau 217 (pTau217), phosphorylated tau 231 (pTau231), and phosphorylated TDP-43 (pTDP-43) were elevated in ALS. NEFL levels positively correlated with pTau181, pTau217, pTau231, and pTDP-43. MAPT and pTDP-43 were also correlated with pTau181, pTau217 and pTau231. Elevated pTau was negatively correlated with survival and ALSFRS-R. Spinal onset ALS was associated with higher pTau181, pTau217, and pTau231.

INTERPRETATION

We confirm previous reports showing elevated pTau181 in ALS plasma and show elevation of other phosphorylated tau forms, pTau217 and pTau231, typically observed in Alzheimer's disease. We provide preliminary data showing the detection and elevation of pTDP-43-409/410 in a subset of ALS samples compared to healthy controls. Neurofilament and tau levels are highly correlated suggesting their elevation may reflect a common pathology and disease state. Total and phosphorylated tau are correlated with multiple disease measures, such as ALS duration, ALSFRS-R, and site of onset.

Variations in neuronal cytoskeletal integrity affect directed communication in distributed networks during inhibitory control

To ensure goal-directed behavior in daily life, the use of inhibitory control is of great importance. The aim of this study is to shed light on the underlying neuronal mechanisms of inhibitory control and the relevance of cytoarchitectonic integrity in it. We combine sophisticated EEG analysis techniques assessing directed communication between brain structures with measurements of neurofilaments as an index of cytoarchitectonic integrity. We show that an extensive theta band activity related neural network with fronto-temporal, parietal, and occipital brain regions is active during response inhibition. Importantly, cytoarchitectonic integrity as measured using neurofilaments modulates nonlinear directional connectivity, particularly when complex reconfiguration of perceptual and action mapping is required. The study thus shows an inter-relation between different levels of biological functioning-the level of cytoarchitectonic integrity and neurophysiological directed communication-for inhibitory control and emphasizes the role of nonlinear brain connectivity in cognitive control.

Associations of Plasma Neurofilament Light Levels With Brain Microstructure and Macrostructure and Cognition in the Community-Based Rhineland Study

BACKGROUND AND OBJECTIVES

Plasma neurofilament light chain (NfL) level is a sensitive yet aspecific marker of neurodegeneration. Its neuroanatomical and functional correlates in the general population are not fully elucidated. We thus assessed how brain's macrostructures and microstructures and cognitive function are related to plasma NfL levels in cognitively unimpaired adults over a wide age range.

METHODS

Our analyses were based on cross-sectional data from the Rhineland Study, a community-based prospective cohort study. This study includes people from the age of 30 onwards who live in 2 geographically defined areas in Bonn, Germany, and have sufficient command of the German language. Plasma NfL levels were measured using the Simoa platform and then log-transformed and adjusted for plate position, batch number, and Analyzer (HD-1 or HD-X). Brain imaging data were collected on a 3 Tesla scanner and included volumetric measures, metrics of the diffusion tensor and the neurite orientation dispersion and density imaging model, and white matter hyperintensity load. Memory performance, processing speed, and executive function were assessed using traditional cognitive tasks and an eye movement battery. We used multivariable regression models to assess the relations between brain structure and plasma NfL levels and between plasma NfL levels and cognitive performance.

RESULTS

The study sample consisted of 5,589 participants aged 30-95 years (mean age 55 ± 13.7 years, 56.1% women) without neurodegenerative diseases. Higher plasma NfL levels were associated with lower isotropic volume fraction (-0.030; 95% CI -0.051 to -0.010; pFDR = 0.011), lower neurite density index (ß = -0.031; 95% CI -0.053 to -0.008; pFDR = 0.014), and higher axial diffusivity (ß = 0.037; 95% CI 0.013-0.062; p = 0.005; pFDR = 0.011). The strongest association was with the orientation dispersion index (ß = -0.063; 95% CI -0.085 to -0.041; pFDR < 0.001). Furthermore, higher plasma NfL levels tended to be associated with a lower processing speed domain score (ß = -0.046; 95% CI -0.084 to -0.009; p = 0.014; pFDR = 0.056) and longer prosaccade latency (ß = 0.039; 95% CI 0.000-0.078; p = 0.049; pFDR = 0.480).

DISCUSSION

Higher plasma NfL levels mainly reflect worse white matter microstructural integrity, especially lower axonal density, in a relatively healthy, community-based sample. This suggests that plasma NfL levels allow for early detection of subtle differences in brain microstructure.

Bile acid metabolites predict multiple sclerosis progression and supplementation is safe in progressive disease

BACKGROUND

Bile acid metabolism is altered in multiple sclerosis (MS) and tauroursodeoxycholic acid (TUDCA) supplementation ameliorated disease in mouse models of MS.

METHODS

Global metabolomics was performed in an observational cohort of people with MS, followed by pathway analysis to examine relationships between baseline metabolite levels and subsequent brain and retinal atrophy. A double-blind, placebo-controlled trial was completed in people with progressive MS (PMS), randomized to receive either TUDCA (2 g/day) or placebo for 16 weeks. Participants were followed with serial clinical and laboratory assessments. Primary outcomes were safety and tolerability of TUDCA, and exploratory outcomes included changes in clinical, laboratory, and gut microbiome parameters.

FINDINGS

In the observational cohort, higher primary bile acid levels at baseline predicted slower whole-brain atrophy, brain substructure atrophy, and specific retinal layer atrophy. In the clinical trial, 47 participants were included in our analyses (21 in placebo arm, 26 in TUDCA arm). Adverse events did not differ significantly between arms (p = 0.77). The TUDCA arm demonstrated increased serum levels of multiple bile acids. No significant differences were noted in clinical or fluid biomarker outcomes. Central memory CD4+ and Th1/17 cells decreased, while CD4+ naive cells increased in the TUDCA arm compared to placebo. Changes in the composition and function of gut microbiota were also noted between the two groups.

CONCLUSIONS

Bile acid metabolism in MS is linked to brain and retinal atrophy. TUDCA supplementation in PMS is safe, tolerable, and has measurable biological effects that warrant further evaluation in larger trials with a longer treatment duration.

FUNDING

National MS Society grant RG-1707-28601 to P.B., R01 NS082347 from the National Institute of Neurological Disorders and Stroke to P.A.C., and National MS Society grant RG-1606-08768 to S.S.

Neurofilaments as Prognostic Biomarkers in the Assessment of the Risk of Advanced Taxane-Induced Neuropathy in Breast Cancer Patients-A Pilot Study

OBJECTIVES

The aim of the present study was to assess the clinical value of measuring the concentration of neurofilament light chains (NF-Ls) in the diagnosis of taxane-induced neuropathy (CIPN) during neoadjuvant chemotherapy (NAC) in breast cancer patients.

METHODS

This study included a total of 94 patients who qualified for NAC with taxanes. Serum samples were collected before starting NAC, after three and six cycles, and 3-6 months after NAC. The NF-L concentration was determined using the Ella technology. The assessment of CIPN was based on the clinical symptoms included in the EORTC QLQ-CIPN20 scores.

RESULTS

The median NF-L concentrations increased during NAT monitoring. After the end of therapy, a significant decrease in NF-L concentrations was observed (p = 0.001, R = 0.37). We established a cut-off point of 29.5 pg/mL to distinguish between the control group and patients with early symptoms of neuropathy (CIPN G1) (p = 0.001; AUC = 0.982). We showed that NF-L concentrations, regardless of the stage of therapy, increased with the severity of neuropathy symptoms (CIPG1 vs. G2 vs. G3) (p = 0.0189, R = 0.33). According to the established cut-off points, serum NF-L concentrations above 196 pg/mL in patients undergoing therapy likely indicate the presence of low-grade neuropathy (p = 0.0076), while values above 218 pg/mL may indicate advanced CIPN (p = 0.0008).

CONCLUSIONS

In this study, we demonstrated the usefulness of NF-L levels to confirm neuropathy early in the course of treatment, which is important as the questionnaire-based assessment of neuropathy currently used in practice remains subjective. Ultimately, serum NF-L levels are helpful in determining the severity of NAC-induced neuropathy among breast cancer patients.

Phosphorylated neurofilament heavy chain (pNfH) concentration in cerebrospinal fluid predicts overall disease aggressiveness (D50) in amyotrophic lateral sclerosis

Introduction

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder, characterized by tremendous clinical heterogeneity that necessitates reliable biomarkers for the trajectory of the disease. The potential of phosphorylated Neurofilament-Heavy-chain (pNfH) measured in cerebrospinal fluid (CSF) to mirror disease progressiveness has repeatedly been suggested but is not applicable as outcome on an individual patient-level. This potential was probably obfuscated before due to imprecise clinical measures of disease progression that assumed a linear decline of motoric function over time. The primary objective was therefore to study if disease aggressiveness, as quantified via the D50 model, would reveal more stable correlations with pNfH.

Methods

ELISA-quantified pNfH CSF levels of 108 patients with ALS were comparatively analyzed in relation to three different measures of disease progression speed via analyses of covariance, linear and non-linear regressions, respectively. These were (a) the D50, depicting a patient's overall disease aggressiveness, (b) cFL, the calculated functional loss-rate as locally derived parameter of progression speed, and (c) DPR, the disease progression-rate as more commonly used linear approximation of points lost per month in the ALS functional rating scale since symptom onset.

Results

All analyses of covariance showed a significant main impact of the respective disease progression-speed parameter on pNfH, independent of disease phase, presence of frontotemporal dementia, analyzing laboratory, sex or clinical onset type, while only age revealed borderline additional influence. Notably, CSF pNfH concentration was independent of how far the disease had progressed, as neither disease phase nor a direct regression with the quantified disease accumulation at the time of lumbar puncture revealed a significant correlation. However, the parameter D50 quantifying aggressiveness showed the most significant impact on pNfH-levels, as compared to the cFL and even more evident in contrast to the DPR. This superiority of D50 was confirmed in direct linear and most evident in non-linear regressions with pNfH.

Conclusion

Overall disease aggressiveness in ALS, as quantified by D50, most robustly correlated with CSF pNfH-levels, independent of the time of collection during symptomatic disease. This opens perspectives to use CSF pNfH as a prognostic outcome measure for future therapeutic interventions in the sense of precision medicine.

Next-Day Serum Glial Fibrillary Acidic Protein Levels to Aid Diagnosis of Sport-Related Concussion

BACKGROUND AND OBJECTIVES

Previous studies on sport-related concussion (SRC) may have measured brain injury blood-based biomarker, glial fibrillary acidic protein (GFAP), either before or after its peak, potentially underestimating the diagnostic value. The primary aim of this study was to evaluate the diagnostic performance of serum GFAP at 24 hours post-SRC. Secondary objectives included assessing whether the timing of sample collection relative to an Australian football match (with or without SRC) affected GFAP levels, evaluating if combining GFAP with symptoms improved discrimination of SRC compared with symptoms alone, and determining the diagnostic utility of serum neurofilament light (NfL) levels at 24 hours post-SRC.

METHODS

In a prospective cohort study, adult male and female Australian football players of the Victorian Amateur Football Association (Melbourne, Australia) with and without SRC had blood sampled around 24 hours postinjury/postmatch. GFAP and NfL levels were quantified using Simoa assays, and area under the curve (AUC) values were calculated for time bins of 16-24 hours, 24-32 hours, and 36-52 hours. Symptom severity at blood collection was assessed using the Sport Concussion Assessment Tool 5 (SCAT).

RESULTS

A total of 151 athletes with SRC (median age 22.5 years; 85% male) and 97 controls (median age 24.3 years; 86% male) were sampled at a median of 24.5 hours (interquartile range [IQR] 21.7-28.0; min-max 16-51.5). Time to sample postmatch did not affect GFAP levels in controls; however, higher GFAP levels correlated with shorter time post-SRC (Spearman r = -0.25, 95% CI -0.40 to -0.09). Median GFAP concentrations were 65.9 pg/mL (IQR 49.1-81.3) in controls, and for SRC, 124.6 pg/mL (IQR 86.7-190.7) at 16-24 hours, 94.5 pg/mL (IQR 61.6-163.9) at 24-32 hours, and 59.9 pg/mL (IQR 49.1-94.7) at 36-52 hours. AUC values at 16-24 and 24-32 hours were 0.83 (95% CI 0.76-0.90) and 0.72 (95% CI 0.64-0.80), respectively. Furthermore, combining GFAP with SCAT symptoms at 16-24 hours enhanced discriminatory capability compared with SCAT symptoms alone (AUC increased from 0.91 to 0.97; z = 2.48, p = 0.01). Serum NfL had a limited diagnostic value (AUC ≤0.60).

DISCUSSION

Serum GFAP measured at 16-24 hours following potential or suspected SRC may be a useful objective aid to SRC diagnosis.

Long-Term Dynamics of CSF and Serum Neurofilament Light Chain in Adult Patients With 5q Spinal Muscular Atrophy Treated With Nusinersen

BACKGROUND AND OBJECTIVES

The availability of disease-modifying therapies for 5q-associated spinal muscular atrophy (SMA) has heightened the need to identify suitable biomarkers. This study investigates neurofilament light chain (NfL) concentrations during long-term nusinersen treatment in adult SMA.

METHODS

In a retrospective study of prospectively collected data, NfL concentrations in the CSF (cNfL) and serum (sNfL) were measured in patients with SMA from 8 German centers and in neurologic controls using a single-molecule array (Simoa) assay. NfL concentrations and clinical characteristics, including the clinical scores Hammersmith Functional Motor Scale Expanded (HFMSE), Revised Upper Limb Module (RULM), and Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R), were analyzed for defined treatment intervals (T1-T4 [loading phase until 4 months], T5-T8 [until 23 months], T9-T12 [until 37 months], and T13-T19 [until 60 months]). Linear mixed models with a random intercept were used to assess the changes in NfL levels during treatment, considering time and covariates as fixed effects.

RESULTS

One hundred thirteen adult patients with SMA (median age 35, 46% female), with a treatment duration of maximum 60 months, and 52 controls were included. At baseline, NfL concentrations were significantly higher in SMA {cNfL median, 585 (interquartile range [IQR] 428-787) pg/mL; sNfL, 11 (IQR 8-14) pg/mL} than in controls (cNfL, 420 [IQR 323-662] pg/mL; sNfL, 8 [IQR 6-12] pg/mL) (cNfL, p = 0.021; sNfL, p = 0.030). Median differences for all clinical scores were the highest for T5-T8 compared with the loading phase (Δ HFMSE, 0.6 [IQR 0.1-1.4], p = 0.017; Δ RULM, 0.9 [IQR 0.4-1.3], p < 0.001; Δ ALSFRS-R, 0.7 [IQR 0.4-1.0], p < 0.001), but not for subsequent intervals. Longitudinal analysis revealed a significant decrease of NfL concentrations during each treatment interval compared with the loading phase (p < 0.05, respectively) except for sNfL in T13-T19. Even among patients with no measurable clinical improvement (Δ HFMSE ≤ 0), more than 50% showed declining cNfL and sNfL levels up to T13-T19.

DISCUSSION

NfL decreased during nusinersen treatment, suggesting its potential as a pharmacodynamic response marker in adult SMA. However, in patients without detectable clinical improvement, our study cannot determine whether they represent a more sensitive outcome measure or are not clinically meaningful.

Serum Proteomic and Metabolomic Signatures of High Versus Low Physical Function in Octogenarians

Physical function declines with aging, yet there is considerable heterogeneity, with some individuals declining very slowly while others experience accelerated functional decline. To gain insight into mechanisms promoting high physical function with aging, we performed proteomics, targeted metabolomics, and targeted kynurenine-focused metabolomic analyses on serum specimens from three groups of octogenarians: High-functioning master athletes (HF, n = 16), healthy normal-functioning non-athletes (NF, n = 12), and lower functioning non-athletes (LF, n = 11). Higher performance status was associated with evidence consistent with: Lower levels of circulating proinflammatory markers, as well as unperturbed tryptophan metabolism, with the normal function of the kynurenic pathway; higher circulating levels of lysophosphatidylcholines that have been previously associated with better mitochondrial oxidative capacity; lower activity of the integrated stress response; lower levels of circulating SASP protein members; and lower levels of proteins that reflect neurodegeneration/denervation. Extending the observations of previous studies focused on the biomarkers of aging that predict poor function, our findings show that many of the same biomarkers associated with poor function exhibit attenuated changes in those who maintain a high function. Because of the cross-sectional nature of this study, results should be interpreted with caution, and bidirectional causality, where physical activity behavior is both a cause and outcome of differences in the biomarker changes, remains a possible interpretation.

Serum Neurofilament Light Chain in Patients with Dominant Optic Atrophy - A Case-Control Study

In numerous neurodegenerative disorders, neurofilaments, especially their subunits such as the Neurofilament light chain (NfL), are recognized as significant biomarkers of axonal injury when increased in blood or cerebrospinal fluid. Dominant optic atrophy (DOA) is characterized by a degeneration of retinal ganglion cells leading to axonal injury. Aim of this study was the evaluation of serum NfL (sNfL) levels in patients with DOA. sNfL concentration was quantified by a Single Molecule Array (Simoa) SR-X analyzer. Primary aim was the comparison of sNfL between patients with OPA1-DOA confirmed by genetic testing and controls. We further investigated associations between sNfL and age, visual acuity, peripapillary retinal nerve fiber layer thickness (pRNFLT) and disease duration. 22 DOA patients and 22 controls were included in this study. sNfL concentration was higher in DOA patients but did not differ significantly between the DOA group (Median (IQR) = 7.39 (5.25, 11.26) and controls (Median (IQR) = 5.86 (4.50, 9.88); p = .405). We found significant correlations between sNfL and age in both groups (DOA group: rho = 0.77, p < .001; control group: rho = 0.79, p < .001). Correlations between sNfL and visual acuity, pRNFLT and disease duration were not significant. Although elevated sNfL values were found in patients with DOA, we did not observe a significant difference between DOA patients and healthy controls.

Physical Activity, Alzheimer Plasma Biomarkers, and Cognition

Importance

Physical activity (PA) is a nonpharmacological intervention for dementia prevention. The association between PA and Alzheimer disease (AD) plasma biomarkers remains underexplored.

Objective

To investigate the associations among PA; plasma biomarkers, including β-amyloid 42/40 (Aβ42/40), phosphorylated-tau217 (ptau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL); and cognition.

Design, Setting, and Participants

This cross-sectional study included participants with and without cognitive impairment recruited from multiple memory clinics in South Korea between May 2019 and May 2022. Data were analyzed from June to December 2024.

Exposures

PA was assessed as metabolic equivalent task minutes per week using the International Physical Activity Questionnaire and categorized into quartiles from the lowest (Q1) to the highest (Q4).

Main Outcomes and Measures

Plasma Aβ42/40, ptau217, GFAP, and NfL were measured. Cognition was assessed using the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating-Sum of Boxes (CDR-SB).

Results

Among 1144 participants (mean [SD] age 70.9 [8.7] years; 744 [65.0%] female), the highest PA quartile showed significantly lower ptau217 (estimate [SE], -0.14 [0.06]; P = .01) and NfL (estimate [SE], -0.12 [0.05]; P = .01) compared with the lowest quartile. Higher PA quartiles were associated with higher MMSE scores (estimate [SE]: Q2, 0.93 [0.31]; P = .003; Q3, 0.82 [0.32]; P = .009; Q4, 0.94 [0.32]; P = .004) and lower CDR-SB scores (estimate [SE]: Q2, -0.33 [0.16]; P = .04; Q3, -0.37 [0.16]; P = .02; Q4, -0.55 [0.16]; P = .001) after adjusting for age, sex, education years, and β-amyloid uptake. In subgroup analyses according to age and cognitive status, the associations of PA and plasma biomarkers with cognition were more pronounced in the older (age ≥65 years) and cognitively impaired groups compared with the younger and cognitively unimpaired groups.

Conclusions and Relevance

These findings suggest that PA may help delay cognitive decline by modulating neurodegeneration and AD-specific tau pathologies. However, the cross-sectional design limits causal inference, and longitudinal studies are needed to confirm and clarify these associations.

A link between baseline neurofilament light chain and primary substrate accumulation in cerebrospinal fluid, and clinical outcomes in patients with MPS II from a phase 2/3 clinical trial and extension study of intrathecal idursulfase

Mucopolysaccharidosis II (MPS II; Hunter syndrome) is a rare, X-linked, recessive lysosomal storage disorder that impacts approximately 1:162000 live births. It is caused by deficiencies in the lysosomal enzyme iduronate-2-sulfatase (I2S), resulting in harmful accumulation of specific glycosaminoglycans in cells, tissues and organs throughout the body. Clinical manifestations are varied and include airway obstruction, impaired mobility and, in two-thirds of cases, neurocognitive impairment (neuronopathic MPS II). Intravenous idursulfase enzyme replacement therapy (elaprase), improves many physical symptoms and signs of the disease but has limited neurological efficacy due to impaired crossing of the blood-brain barrier. TAK-609 is an intrathecal formulation of idursulfase (idursulfase-IT) that is delivered directly to the cerebrospinal fluid (CSF) of patients with neuronopathic MPS II to attenuate the neurocognitive decline. This study investigated the relationship between clinical outcomes of patients treated with TAK-609 and levels of neurofilament light chain (NfL), a component of the neuronal cytoskeleton that accumulates under neurodegenerative conditions. We report an association between the severity of I2S gene (IDS) variants and baseline CSF NfL levels in patients with neuronopathic MPS II that corresponded to primary substrate burden as measured by heparan sulfate and total GAGs. Supraphysiological (high) NfL levels corresponded to a more rapid rate of cognitive decline than physiological (normal) baseline levels. Taken together, this study establishes a clear link between genetic status, accumulation of primary substrate and circulating CSF NfL levels, allowing for bioanalytical stratification of patient outcomes in MPS II. TAKE-HOME MESSAGE: Baseline cerebrospinal neurofilament light chain levels correspond to the severity of iduronate-2-sulfatase gene (IDS) genotype, the degree of primary substrate burden and subsequent clinical outcomes in patients with neuronopathic mucopolysaccharidosis II, and can complement clinical assessments of disease heterogeneity.

Blood biomarkers differentiate AD-related versus non-AD-related cognitive deficits

INTRODUCTION

The utility of blood-based biomarkers for discriminating Alzheimer's disease (AD)-related versus non-AD-related cognitive deficits in preclinical populations remains poorly understood. Here, we tested the capability of blood markers to detect and discriminate variation in performance across multiple cognitive domains in a cognitively unimpaired sample.

METHODS

Participants (n = 648, aged 69.9 ± 3.8, 71% female) underwent a comprehensive cognitive assessment and assays for plasma-based biomarkers amyloid beta (Aβ)1-42/1-40 by mass spectrometry, phosphorylated tau (p-tau) 181 and 217, p-tau217/Aβ1-42, glial fibrillary acidic protein (GFAP), and neurofilament light (NfL).

RESULTS

Greater p-tau217 was exclusively associated with poorer episodic memory performance (β = -0.11, SE = 0.04, p = .003), and remained so after covarying for NfL. Higher NfL was non-specifically associated with poorer performance across a range of cognitive domains and remained so after covarying for p-tau217.

DISCUSSION

Blood-based biomarkers may differentiate non-AD-related versus AD-related cognitive deficits. This characterization will be important for early intervention and disease monitoring for AD.

HIGHLIGHTS

There is heterogeneity in the causes of cognitive decline in aging. AD-related blood biomarkers may help characterize these causes. Elevated p-tau217 was exclusively associated with poorer episodic memory. Elevated NfL was associated with poorer cognition in a broad range of domains. Blood biomarkers may help differentiate AD- and non-AD-related cognitive deficits.

Cognitive decline and neuroinflammation in a mouse model of obesity: An accelerating role of ageing

Obesity, a pandemic, worldwide afflicts almost one billion people. Obesity and ageing share several pathological pathways leading to neurological disorders. However, due to a lack of suitable animal models, the long-term effects of obesity on age-related disorders- cognitive impairment and dementia have not yet been thoroughly investigated. Therefore, the current investigation focuses on developing a suitable model to explore the effects of obese-ageing. It also aims to determine whether obesity affects cognitive abilities in an age-dependent manner, and to identify a potential biomarker(s) for cognitive decline. Cognitive tests were carried out on 6-months and 1-year-old melanocortin-4 receptor (Mc4r)-deficient-obese and lean (wildtype) mice. Additionally, brains and sera were harvested for molecular, histological and serological analyses from 6, 12, and 24-months-old mice. Finally, RT-PCR was carried out after hippocampal mRNA sequencing. The cognitive tests revealed that 1-year-old obese mice have cognitive impairment along with underlying neurodegenerative changes, such as enlarged lateral ventricles. Serum neurofilament light chain (sNfL) levels were also elevated. Lipid accumulation and neuroinflammation were apparent besides, a compromised blood-brain barrier (BBB) indicated by altered junction protein gene expression. Differentially-expressed genes associated with cognitive decline were identified by mRNA sequencing of hippocampi. One such gene, Secreted Phosphoprotein 1 (Spp1) had markedly increased expression in cognitively-impaired obese mice. Our findings present an obese-aged mouse model of cognitive decline with neuroinflammation, reduced BBB-integrity and predisposing neurodegenerative changes. Obese-ageing accelerates the progression of cognitive impairment. Furthermore, Spp1 appears to be a potential biomarker for early diagnosis of neuropathological disorders.

APOE and TREM2 variants differentially influence glial fibrillary acidic protein and neurofilament light in plasma of UK Biobank participants

Plasma levels of protein biomarkers glial fibrillary acidic protein (GFAP) and neurofilament light (NEFL) are key dementia biomarkers, but it is unclear how risk genes for Alzheimer's disease (AD) influence levels of these biomarkers. We investigated the association of the established high-effect variants for AD in APOE and TREM2 with these biomarkers, using data from over 50,000 participants from the UK Biobank (UKB). The results show that APOE4 is associated with elevated levels of plasma GFAP, and to a lesser extent, NEFL. The APOE4 effect on GFAP increases with age and the number of APOE4 alleles. The risk variants R47H and R62H in TREM2 are associated with higher NEFL levels, but not with GFAP, and the effect sizes do not increase with age. Higher levels of both GFAP and NEFL in midlife are significantly associated with greater risk for incident dementia. In contrast, the protective APOE2 allele showed no effect on GFAP or NEFL. In conclusion, we find that major genetic risk factors for AD differentially affect dementia protein biomarkers across age, indicating gene specific pathways with potential therapeutic implications.

Biomarkers in Subclinical Transthyretin Cardiac Amyloidosis

PURPOSE OF REVIEW

The most common type of cardiac amyloidosis is transthyretin amyloidosis (ATTR-CM). Early forms of the disease can often go undetected. Effective pharmacological treatments are available for ATTR-CM. However, current treatment options may be more effective when used earlier in the disease, making early detection paramount. Below, we discuss updates with regards to the role that blood-based biomarkers play in detecting subclinical cardiac amyloidosis.

RECENT FINDINGS

Carriers of amyloidogenic mutations in the TTR gene are at a heightened risk of developing heart failure and have higher mortality rates compared with noncarrier counterparts. Conventional biomarkers, such as the cardiac troponins and natriuretic peptides, may be useful to monitor subclinical cardiac amyloidosis. In addition, recent studies have demonstrated links between amyloidogenic TTR carrier status and low levels of circulating transthyretin (TTR) and retinol-binding protein 4 (RBP4). Laboratory advances have also allowed for the development of peptide-based detection methods. Probes targeting transthyretin aggregates and nonnative TTR peptides have shown promise in differentiating ATTR from non-ATTR amyloidosis populations. Finally, recent studies have identified neurofilament light chains as potential biomarkers for detecting polyneuropathy-predominant amyloidosis. Conventional biomarkers, such as cardiac troponin and natriuretic peptides may indicate evolving amyloid deposition in early ATTR-CM. However, they are non-specific and emerging biomarkers such as serum transthyretin levels, retinol-binding protein 4, transthyretin aggregates, nonnative TTR, and neurofilament light chains may hold promise in characterizing subclinical ATTR.

Blood-based biomarkers suggest prolonged axonal Injury following pediatric mild traumatic brain injury

Pediatric mild traumatic brain injury (pmTBI) affects millions of youth annually but underlying pathophysiology and time for physiological recovery remains unknown. Non-fasting plasma samples were obtained in 59 pmTBI (28 females; age 14.9 ± 2.7) at approximately 7 days and 4 months post-injury and in 41 matched healthy controls (HC: 20 females; age 14.3 ± 2.8). Samples were analyzed for GFAP, NFL, Tau, pTau181 and UCH-L1 protein concentrations in conjunction with a clinical battery. Significant effects of diagnosis (pmTBI > HC) existed at ~ 7 days (p < 0.001; Cohen's d = 0.72) and ~ 4 months (p = 0.015; Cohen's d = 0.41) post-injury for NFL. NFL was also elevated in pmTBI with significant alterations to mental status (e.g., post-traumatic amnesia) relative to patients without (p = 0.014; Cohen's d = 0.77). UCH-L1, GFAP and pTau181 did not differ between groups, but demonstrated negative associations with days post-injury (small to medium effect sizes) suggestive of a more rapid release/clearance. Post-concussive symptoms had the best diagnostic classification accuracy at ~ 7 days, but NFL ranked higher at 4 months post-injury. Preliminary findings highlight dynamic fluctuations in blood-based biomarkers in the first week of pmTBI, with ongoing evidence of protein release (NFL) at 4 months. NFL demonstrated additional promise for delineating injury severity within the spectrum of pmTBI.

Neurofilament light chain level is associated with lifetime suicidal behaviors

BACKGROUND

Suicide is among the severe outcomes of mental illness and has been reported to be associated with neurodegeneration and cognitive impairment. The blood neurofilament light chain (NfL) level is a biomarker of neuronal damage in neuropsychiatric disorders. This study investigated whether the NfL levels are associated with lifetime suicidal behaviors and whether this level is higher in patients with major depressive disorder (MDD) compared with healthy controls.

METHODS

In this cross-sectional study, we included 73 patients with MDD and 40 age- and sex-matched controls. The blood NfL levels were measured using an enzyme-linked immunosorbent assay. We compared the NfL levels between patients with MDD and controls and performed regression analysis to evaluate the association between the NfL levels and suicidal behaviors.

RESULTS

Nearly half of the patients with MDD (43.80%) reported lifetime suicide attempts. Those with MDD had higher blood NfL levels, but their levels did not significantly differ from those of the healthy controls. Logistic regression results revealed higher risks of lifetime suicide planning (Odds ratio [OR] = 1.64) and suicide attempts (OR = 1.94) with every 10 pg/mL increase in the NfL levels.

CONCLUSIONS

Our results demonstrate that higher serum NfL levels were associated with lifetime suicidal behavior.

Renal function's impact on serum neurofilament levels in patients with multiple sclerosis: an exploratory analysis

BACKGROUND

sNfL, a promising biomarker for neuroaxonal damage in Multiple Sclerosis (MS), requires cautious interpretation due to several comorbidity influences.

OBJECTIVES

To investigate the impact of renal function on sNfL levels in MS patients.

METHODS

This retrospective study stratified patients by MS clinical phenotype, acute inflammatory activity (AIA) status-defined as relapse or gadolinium-enhancing lesions within 90 days of sample collection-renal function, assessed by estimated glomerular filtration rate (eGFR), and age (< 40 years, 40-60 years, > 60 years). Comparative analysis of sNfL levels across these groups was performed. The sNfL-eGFR relationship was examined using linear and non-linear regression models, with the best fit determined by R2 and the F estimator.

RESULTS

Data from 2933 determinations across 800 patients were analyzed. Patients with renal insufficiency (RI) (eGFR < 60 mL/min/1.73 m2) and mild renal impairment (MDRF) (eGFR 60-90 mL/min/1.73 m2) showed significantly higher sNfL levels compared to those with normal renal function, a pattern also observed in age groups 40 years and older. No significant differences were found between MDRF patients and those with AIA. Among RI patients, no differences in sNfL levels were observed between relapsing-remitting and progressive MS phenotypes. A regression S-Curve model was identified as the best fit, illustrating a marked increase in sNfL levels beginning at an eGFR of approximately 75 mL/min/1.73 m2.

DISCUSSION

Caution is advised when interpreting sNfL levels for monitoring MS in patients with impaired renal function.

Elevated neurofilament light chain associated with cobalt/chromium metal neurotoxicity in a patient with a failed hip implant

BACKGROUND

It is known that the heavy metals cobalt and chromium are associated with neurotoxicity. Chromium (Cr) and Cobalt (Co) are both components of metal-on-metal (MoM) implants which can be degraded/fragmented and released into the bloodstream. Neurofilament Light Chain (NfL) is a neuron-specific protein that increases in serum following axonal damage. Here, we report a novel case of a patient with neurotoxic concentrations of serum Co and Cr stemming from fragments of a Metal on Metal (MoM) hip implant exhibiting elevated serum NfL concentrations.

CASE PRESENTATION

A 56-year-old female patient with ceramic and metal fragments left in her body after hip arthroplasty revision presented with symptoms consistent with Co/Cr neurotoxicity. Serum Co, Cr and NfL concentrations were measured to assess metal ion exposure and its potential link to her neurological symptoms. Over four months following two revision surgeries, her serum Co and Cr concentrations decreased significantly from their peak levels, along with a concomitant decrease in NfL concentrations. During this period, the patient's pathological neurological symptoms gradually resolved, with serum Co, Cr, and NfL concentrations approaching normal ranges.

CONCLUSION

Serum NfL is elevated in a patient exhibiting neurotoxicity from Co/Cr implant exposure. The potential utility of serum NfL as a biomarker for metal associated neurotoxicity should be further explored.

Disentangling relationships between Alzheimer's disease plasma biomarkers and established biomarkers in patients of tertiary memory clinics

BACKGROUND

Several plasma biomarkers for Alzheimer's disease (AD) have demonstrated diagnostic and analytical robustness. Yet, contradictory results have been obtained regarding their association with standard diagnostic markers of AD. This study aims to investigate the specific relationship between the AD biomarkers currently used in clinical practice and the plasma biomarkers.

METHODS

In a memory clinic cohort, we analysed plasma pTau181, pTau217, pTau231, respectively, GFAP, NfL, CSF pTau181, Aβ-PET scans, and MRI/CT visual read of atrophy. We utilized methods based on multiple linear regression to evaluate the specific associations between clinically used and recently developed plasma biomarkers, while also considering demographic variables such as age and sex.

FINDINGS

Although plasma pTau181, pTau217, pTau231, and GFAP were significantly associated with both Aβ-PET and CSF pTau181, Aβ-PET explained more variance in the levels of these biomarkers. The effect of CSF pTau181 on plasma GFAP and pTau181 was completely attenuated by Aβ-PET, whereas pTau231 and pTau217 were affected by both Aβ-PET and CSF pTau181 levels. Unlike these biomarkers, increased NfL was rather indicative of brain atrophy and older age. Based on the effect sizes, plasma pTau217 emerged as highly effective in distinguishing between A+ and A-, and T+ and T- individuals, with 60% of variance in plasma pTau217 explained by clinical AD biomarkers.

INTERPRETATION

Amyloid burden primarily drives the changes in plasma pTau181, pTau217, pTau231, and GFAP. In contrast to plasma pTau217, a significant portion of variance in plasma pTau181, pTau231, GFAP, NfL remains unexplained by clinical AD biomarkers.

FUNDING

This research is supported by the Swedish Research Council VR: 2017-06086, 2020-4-3018, 2024-2027; Swedish Brain Foundation, Swedish Alzhzeimer Foundation, CIMED Region Stockholm/Karolinska Institutet; the Region Stockholm - Karolinska Institutet regional agreement on medical training and clinical research (ALF), Fondation Recherche sur Alzheimer (France).

Artificial intelligence modeling of biomarker-based physiological age: Impact on phase 1 drug-metabolizing enzyme phenotypes

Age and aging are important predictors of health status, disease progression, drug kinetics, and effects. The purpose was to develop ensemble learning-based physiological age (PA) models for evaluating drug metabolism. National Health and Nutrition Examination Survey (NHANES) data were modeled with ensemble learning to obtain two PA models, PA-M1 and PA-M2. PA-M1 included body composition, blood and urine biomarkers, and disease variables as predictors. PA-M2 had blood and urine-derived variables as predictors. Activity phenotypes for cytochrome-P450 (CYP) CYP2E1, CYP1A2, CYP2A6, xanthine oxidase (XO), and N-acetyltransferase-2 (NAT-2) and telomere attrition were assessed. Bayesian networks were used to obtain mechanistic systems pharmacology model structures for PA. The study included n = 22,307 NHANES participants (51.5% female, mean age 46.0 years, range: 18-79 years). The PA-M1 and PA-M2 distributions had greater dispersion across age strata with a right skew for younger age strata and a left skew for older age strata. There was no evidence of algorithmic bias based on sex or race/ethnicity. Klotho, lean body mass, glycohemoglobin, and systolic blood pressure were the top four predictors for PA-M1. Glycohemoglobin, serum creatinine, total cholesterol, and urine creatinine were the top four predictors for PA-M2. The models also performed satisfactorily in independent validation. Model-predicted PA was associated with CYP2E1, CYP1A2, CYP2A6, XO, and NAT-2 activity. Telomere attrition was associated with greater PA-M1 and PA-M2. Ensemble learning models provide robust assessments of PA from easily obtained blood and urine biomarkers. PA is associated with Phase I drug-metabolizing enzyme phenotypes.

Association of serum neurofilament light chain with cognitive impairment: findings from the National Health and Nutrition Examination Survey

Background

Serum Neurofilament Light chain (NfL) is a promising biomarker of neuronal damage, used to assess the extent of neuronal injury and neurodegeneration, and it is widely applied in the diagnosis of neurodegenerative disease and monitoring disease progression. This article aims to determine whether serum NfL associated with cognitive level.

Methods

Using NHANES data, we conducted an analysis of cognitive test results for 450 adults aged 60 years and older and examined their correlation with serum NfL levels. When exploring the association between cognitive test scores and serum NfL levels, regression models and restricted cubic spline (RCS) regression models were employed to adjust for potential confounding factors. The least absolute shrinkage and selection operator (LASSO) regression was applied for identifying key cognitive impairment factors, which was then included in the establishment of a risk prediction nomogram model, with the receiver operating characteristic (ROC) curve being built to evaluate its discriminatory power for cognitive impairment.

Results

It was found that there is a strong positive correlation between serum NfL levels and both low total cognitive function (total-CF) OR: 1.028 (95%CI = 1.015-1.041 p < 0.001) and low Digit Symbol Substitution Test (DSST) OR: 1.026 (95%CI = 1.003-1.050, p = 0.027). Furthermore, using the RCS model, we observed a linear trend in the relationship between NfL and low total-CF. The nomogram model based on NfL identified by LASSO regression displayed a considerable predicative value for low total-CF, with an area under the curve [AUC = 85.6% (81.6-89.3%)].

Conclusion

There is a strong correlation between serum NfL levels and cognitive function, especially DSST, which reflects attention and information processing abilities, as well as overall cognitive function, but not memory and language fluency. Thus, NfL may serve as a serum biomarker for dementia monitoring.

Elevated serum neurofilament light chain levels in patients with neuropsychiatric systemic lupus erythematosus: a cross-sectional study

BACKGROUND

The neurofilament light chain (NfL) in cerebrospinal fluid (CSF) and serum as a marker of neuronal damage may be a potential biomarker of neuropsychiatric involvement in SLE (NPSLE).

METHODS

80 patients with SLE were included.We obtained paired serum and CSF samples from 48 patients (NPSLE n=32, non-NPSLE n=16) and 31 controls. The serum and CSF levels of NfL were determined using ELISA.

RESULTS

Patients with NPSLE demonstrated significantly higher levels of serum NfL compared with the non-NPSLE group (mean 31.68±36.63 pg/mL vs mean 16.75±12.48 pg/mL, respectively, p<0.05) and with controls (mean 10.74±4.36 pg/mL, p<0.01). Notably, CSF NfL concentrations in patients with NPSLE showed an upward trend (mean 1600±2852 pg/mL) in contrast to non-NPSLE patients (mean 393.4±191.9 pg/mL) and controls (mean 509.7±358.5 pg/mL). Furthermore, a positive correlation was observed between serum and CSF NfL levels in patients with NPSLE (R=0.8686, p<0.01). Elevated serum triacylglycerol concentrations, C reactive protein and organ damage were linked to increased serum (p=0.002; p<0.001; p=0.036) and CSF (p=0.008; p=0.007; p<0.001) NfL concentrations. In addition, we established a significant correlation between intrathecal NfL concentrations and interleukin-6 levels in the CSF of patients with NPSLE (R=0.5118, p<0.05).

CONCLUSION

The serum NfL levels may be a readily available marker of neuropsychiatric involvement in SLE.

Exploring the Link Between Renal Function Fluctuations Within the Physiological Range and Serum/CSF Levels of NfL, GFAP, tTAU, and UCHL1

Impaired renal function can influence biomarker levels through mechanisms involving blood-brain barrier integrity and clearance pathways; however, the impact of variations within normal renal function remains unclear. The main aim of this study was to determine whether adjustment for the specific level of renal function is necessary when renal function remains within physiological levels. We studied n = 183 patients (NID n = 122; other neurological diseases n = 39; somatoform controls n = 22) who underwent lumbar puncture at University Hospital Frankfurt. Serum and cerebrospinal fluid (CSF) levels of neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), total tau protein (tTAU), and ubiquitin C-terminal hydrolase-L1 (UCHL1) were measured using the single molecule array (SIMOA) technique. Estimated glomerular filtration rate (eGFR) correlated negatively with CSF GFAP (r = -0.217, p = 0.004) and serum NfL (r = -0.164, p = 0.032). Patients with impaired renal function exhibited higher CSF NfL (p = 0.036) and CSF GFAP (p = 0.026) levels. However, these findings did not remain significant after adjusting for BMI and age. Importantly, in patients with normal renal function, no significant correlations with eGFR and biomarker levels were observed after adjustment. Our findings indicate that serum and CSF concentrations of NfL, GFAP, tTAU, and UCHL1 are not significantly affected by fluctuations in physiological kidney function but emphasize the importance of considering comorbidities in impaired renal function when interpreting biomarker levels.

Association of plasma biomarkers of Alzheimer's pathology and neurodegeneration with gait performance in older adults

BACKGROUND

Declining gait performance is seen in aging individuals, due to neural and systemic factors. Plasma biomarkers provide an accessible way to assess evolving brain changes; non-specific neurodegeneration (NfL, GFAP) or evolving Alzheimer's disease (Aβ 42/40 ratio, P-Tau181).

METHODS

In a population-based cohort of older adults, we evaluate the hypothesis that plasma biomarkers of neurodegeneration and Alzheimer's Disease pathology are associated with worse gait performance. A sample of 2641 Mayo Clinic Study of Aging participants with measurements of plasma biomarkers and gait parameters was analyzed in this cross-sectional study. Linear regression models using plasma biomarkers as predictors of gait parameters and adjusted for age, sex, BMI, Charlson Comorbidity Index, and cognitive diagnosis were evaluated.

RESULTS

In this study multiple statistically significant relationships are observed for GFAP, NfL, and P-Tau181 with gait parameters. Each standard deviation increase in GFAP, NfL, and P-Tau181 is associated with a reduction in velocity of 2.100 (95% CI: -3.004, -1.196; p = 5.4 × 10-6), 4.400 (-5.292, -3.507; p = 9.5 × 10-22), and 2.617 (-3.414, -1.819; p = 1.5 × 10-10) cm/sec, respectively. Overall, NfL has the strongest associations with poor gait performance. Models with age interactions show that the strength of associations between the plasma biomarkers and the gait parameters became stronger with increasing age. There are no specific gait parameters that associate with individual plasma biomarkers.

CONCLUSION

Plasma biomarkers of neurodegeneration and Alzheimer's Disease pathology are not only markers of cognitive decline but also indicate motor decline in the aging population.

Evaluating plasma biomarkers NfL, GFAP, GDF15, and FGF21 as indicators of disease severity in Charcot-Marie Tooth patients

Background

Charcot-Marie-Tooth disease (CMT), a slowly advancing hereditary nerve disorder, presents a significant challenge in the medical field. Effective drugs for treatment are lacking, and we struggle to find sensitive markers to track the disease's severity and progression. In this study, our objective was to investigate the levels of neurofilament light chain (NfL), glial fibrillary acid protein (GFAP), fibroblast growth factor 21 (FGF-21) and growth differentiation factor 15 (GDF-15) in individuals with CMT and to compare them to a control group. Our primary goal is to determine whether these biomarker levels are related to the severity of the disease.

Methods

Initially, 44 patients with CMT and 44 controls participated in this study. CMT diagnosis was approved by genetic testing. Disease severity was assessed through clinical evaluations using the CMT Neuropathy Score version 2 (CMTNSv2). NfL and GFAP concentrations were measured using Single molecule array, while FGF-21 and GDF-15 concentrations were measured by enzyme-linked immunosorbent assays.

Results

In the group of patients with CMT, the concentrations of GDF15, FGF21, NfL, and GFAP were significantly higher than in the control group (p < 0.05). NfL and GFAP levels were correlated with the CMTNSv2 score (rs = 0.46, p = 0.002; rs = 0.31, p = 0.04).

Conclusion

Our study has provided confirmation that plasma concentrations of NfL, GFAP, GDF15, and FGF21 are significantly elevated in patients with CMT compared to controls. Furthermore, NfL and GFAP levels were correlated with the clinical severity of CMT. These findings suggest that NfL and GFAP can be reliable disease indicators in future research.

A French multicenter analytical evaluation of the automated Lumipulse G sNfL blood assay (Fujirebio®) and its comparison to four other immunoassays for serum neurofilament light chain assessment in clinical settings

OBJECTIVES

Measurement of serum neurofilament light chain (sNfL) protein is becoming a key biomarker for many neurological diseases. Several immunoassays have been developed to meet these clinical needs, revealing significant differences in terms of variability and results. Here, we propose a French multicenter comparison of 5 sNfL assays.

METHODS

6 replicates of 3 pools with low (10 pg/mL), medium (30 pg/mL) and high (100 pg/mL) sNfL values and one replicate of 12 samples with growing sNfL values were analyzed by six independent French clinical laboratories. The analytical performances of the sNfL blood assay (Fujirebio®) on Lumipulse G were first evaluated then compared to four other immunoassays: NF-light V2 (Quanterix®) on SiMOA HD-X, Human NF-L (Biotechne®) on Ella, R-Plex Human Neurofilament L (MSD®) on Sector 2400; manual ELISA test using Uman Diagnostic/Quanterix®.

RESULTS

Inter-center comparison of the Lumipulse blood assay revealed limited but significant differences in the mean sNfL values across low, medium, and high pools between each city (p < 0.001) and between the two different batches used. Coefficients of variation of pools ranged from 2.0 to 16.9 %. Z-score of sNfL results of the 12 samples ranged from -1.70 to +1.71. Inter-technique comparison showed a systematic difference of sNfL values, with a overestimation of MSD and Ella over other tests. Nonetheless, results were all significantly correlated (p < 0.001).

CONCLUSION

The automated Lumipulse assay produced comparable sNfL values across laboratories; but further adjustments are needed to harmonize sNfL results. Biologists and physicians should be aware of the variability in results between different immunoassay suppliers.

Neurofilament light chain (Nf-L) in cerebrospinal fluid and serum as a potential biomarker in the differential diagnosis of neurological diseases in cattle

Neurofilament light chain (Nf-L) is a biomarker for axonal damage in human neurology but is understudied in cattle. With this study we wanted to determine Nf-L stability at two different storage temperatures and Nf-L levels in healthy cattle and the relationship with age, evaluate whether Nf-L holds diagnostic potential for neurological disorders, and whether an association exists between Nf-L in serum and in cerebrospinal fluid (CSF). To do this, we measured Nf-L levels in CSF and serum samples from 49 healthy and 75 sick cattle. Storage at -80 °C or -20 °C had no impact on Nf-L concentration. Physiological median Nf-L levels were 6.3 pg/mL (serum) and 414 pg/mL (CSF) in calves and 5.5 pg/mL (serum) and 828 pg/mL (CSF) in adult cattle. There was no association between Nf-L levels in CSF and calf age (r2 0.07, p = 0.13), while a weak association was found for Nf-L in serum (r2 0.26, p = 0.01), and a significant association in adult cattle (CSF, r2 0.69, p = 0.0001; serum, r2 0.68, p = 0.0003). CSF Nf-L levels were higher in samples from animals with degenerative (median Nf-L 49971 pg/mL) and infectious central nervous system (CNS) disorders (median Nf-L, age < 2 months 8863 pg/mL; age 2-12 months 17474 pg/mL; age 1-6 years 3546 pg/mL), CNS anomalies and metabolic/toxic disorders. There was a significant association between CSF Nf-L and serum Nf-L in cattle with neurological disorders (r2 0.2, p = 0.009). Taken together, these findings suggest the potential of Nf-L as a diagnostic tool in cattle neurology.

No Relation Between Cognitive Impairment, Physical Disability and Serum Biomarkers in a Cohort of Progressive Multiple Sclerosis Patients

Despite significant efforts, there is still an existing need to identify diagnostic tools that would enable fast and reliable detection of the progressive stage of multiple sclerosis (MS) and help in monitoring the disease course and/or treatment effects. The aim of this prospective study in a group of people with progressive MS was to determine whether changes in the levels of selected serum biomarkers and in cognitive function may predict disease progression, and therefore refine the decision-making process in the evaluation of MS patients. Forty two (42) patients with progressive MS completed all the study procedures; the mean duration of follow-up was 12.97 months. During the observation period, serum concentration of chitinase-3 like-protein-1 (CHI3L1/YKL-40) decreased significantly in the whole study group (from 4034.95 ± 262.62 to 2866.43 ± 173.37; p = 0.0005), as well as in subgroups of people with secondary progressive and primary progressive MS (SPMS: from 3693.81 ± 388.68 to 2542.76 ± 256.59; p = 0.0207; and PPMS: from 4376.09 ± 353.27 to 3190.09 ± 233.22; p = 0.0089, respectively). A significant worsening of Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) scores was detected in the whole study group (from 1.18 ± 0.14 to 1.34 ± 0.15; p = 0.0331) as well as in the PPMS subgroup (from 1.04 ± 0.18 to 1.26 ± 0.20; p = 0.0216). No correlations between the analyzed molecular parameters or the results of neuropsychological tests and physical disability were observed. In conclusion, an emphasis should be placed on furthering the search for multimodal biomarkers of disease progression, especially in the PMS population, based on simultaneous analysis of several factors, such as blood biomarkers and cognitive profiles.

Brain injury biomarkers and applications in neurological diseases

ABSTRACT

Neurological diseases are a major health concern, and brain injury is a typical pathological process in various neurological disorders. Different biomarkers in the blood or the cerebrospinal fluid are associated with specific physiological and pathological processes. They are vital in identifying, diagnosing, and treating brain injuries. In this review, we described biomarkers for neuronal cell body injury (neuron-specific enolase, ubiquitin C-terminal hydrolase-L1, αII-spectrin), axonal injury (neurofilament proteins, tau), astrocyte injury (S100β, glial fibrillary acidic protein), demyelination (myelin basic protein), autoantibodies, and other emerging biomarkers (extracellular vesicles, microRNAs). We aimed to summarize the applications of these biomarkers and their related interests and limits in the diagnosis and prognosis for neurological diseases, including traumatic brain injury, status epilepticus, stroke, Alzheimer's disease, and infection. In addition, a reasonable outlook for brain injury biomarkers as ideal detection tools for neurological diseases is presented.

Metal mixtures exposure with risk of elevated serum neurofilament light chain concentrations in U.S. general adults, NHANES 2013-2014

BACKGROUND

A relatively well-established link was observed between metal mixtures exposure and neurodegenerative diseases. However, the relationship between metal mixtures exposure and serum neurofilament light chain (sNfL) concentrations, a valuable non-invasive biomarker of neurodegenerative diseases, in general adult populations remains understudied and unclear.

OBJECTIVE

This study seeks to elucidate the potential impact of metal mixtures exposure on sNfL concentrations in a representative sample of U.S. general adults.

METHODS

Twelve urinary metal levels, including barium (Ba), cadmium (Cd), cobalt (Co), cesium (Cs), molybdenum (Mo), lead (Pb), antimony (Sb), tin (Sn), strontium (Sr), thallium (Tl), tungsten (W) and uranium (U), were analyzed in U.S. general adults recruited from the 2013-2014 National Health and Nutrition Examination Survey using inductively coupled plasma mass spectrometry (ICP-MS) after a simple dilution step. Urine samples are diluted with 2 % concentrated nitric acid (1:9). We employed a two-pronged approach, combining weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models, to examine the association between the multiple-metals effect and sNfL concentrations. Survey-weighted multivariate linear regression was used to explore the correlation between single-metal effect and sNfL concentrations.

RESULTS

With the increasing quartiles of log-transformed sNfL (log-sNfL) concentrations, the fourth quartile had a higher proportion of smokers and hypertensive individuals (P < 0.001). Cd (69.6 %) and Pb (8.9 %) were the primary drivers of the association between metal mixtures exposure and sNfL concentrations. Analysis of WQS and BKMR models showed a positive association between metal mixtures exposure and sNfL concentrations, especially in older, and male participants.

CONCLUSION

In the U.S. general adult, a significant correlation between metal mixtures exposure and increased sNfL concentrations was observed, and urinary Cd levels play a pivotal role in this positive correlation. Notably, stronger risk associations were observed among elderly, males, smokers, and hypertensive individuals. The results could be significant for detecting and tracking the beginning of neurodegenerative diseases early, as well as helping to pinpoint individuals at high risk.

Are white matter hyperintensities associated with neuroborreliosis? The answer is twofold

PURPOSE

Many consider white matter hyperintensities (WMHs) to be important imaging findings in neuroborreliosis. However, evidence regarding association with WMHs is of low quality. The objective was to investigate WMHs in neuroborreliosis visually and quantitatively.

MATERIALS AND METHODS

Patients underwent brain MRI within one month of diagnosis and six months after treatment. Healthy controls were recruited. WMHs were counted by visual rating and the volume was calculated from automatic segmentation. Biochemical markers and scores for clinical symptoms and findings were used to explore association with longitudinal volume change of WMHs.

RESULTS

The study included 74 patients (37 males) with early neuroborreliosis and 65 controls (30 males). Mean age (standard deviation) was 57.4 (13.5) and 57.7 (12.9) years, respectively. Baseline WMH lesion count was zero in 14 patients/16 controls, < 10 in 36/31, 10-20 in 9/7 and > 20 in 13/11, with no difference between groups (p = 0.90). However, from baseline to follow-up the patients had a small reduction in WMH volume and the controls a small increase, median difference 0.136 (95% confidence interval 0.051-0.251) ml. In patients, volume change was not associated with biochemical or clinical markers, but with degree of WMHs (p values 0.002-0.01).

CONCLUSION

WMH lesions were not more numerous in patients with neuroborreliosis compared to healthy controls. However, there was a small reduction of WMH volume from baseline to follow-up among patients, which was associated with higher baseline WMH severity, but not with disease burden or outcome. Overall, non-specific WMHs should not be considered suggestive of neuroborreliosis.

Real-World Safety and Effectiveness of Dimethyl Fumarate in Patients with MS: Results from the ESTEEM Phase 4 and PROCLAIM Phase 3 Studies with a Focus on Older Patients

INTRODUCTION

Real-world studies in the USA report that 41-56% of patients with multiple sclerosis (MS) are ≥ 50 years old, yet data on their response to disease-modifying therapies (DMTs) is limited. Dimethyl fumarate (DMF) is an oral DMT approved for treating relapsing MS. This analysis evaluated the safety, efficacy, and immunophenotype changes of DMF in patients ≥ 50 years compared with patients < 50 years.

METHODS

ESTEEM, a 5-year, real-world, observational phase 4 study, assessed the safety and effectiveness of DMF, including treatment-emergent serious adverse events (SAEs) and adverse events (AEs) leading to treatment discontinuation. Absolute lymphocyte counts (ALCs) were recorded from a subset of patients. The PROCLAIM study, a phase 3b interventional study, reported safety outcomes and lymphocyte subset changes in patients with relapsing-remitting MS (RRMS) treated with DMF. The study evaluated safety outcomes by analyzing the incidence of SAEs and detailed changes in CD4+ and CD8+ T cell compartments over 96 weeks of DMF treatment.

RESULTS

ESTEEM included 4020 patients aged < 50 years and 1069 aged ≥ 50 years. AEs leading to discontinuation were reported by 19.6% patients < 50 years and 29.6% of patients ≥ 50 years, with gastrointestinal disorders being the most common. SAEs were reported by 5.2% of patients < 50 years and 8.9% those ≥ 50 years. In PROCLAIM, SAEs were reported in 13% of patients < 50 years and 10% of those ≥ 50 years. Median ALC decreased by 35% in patients < 50 years and 50% in those ≥ 50 years in ESTEEM, with similar patterns observed in PROCLAIM.

CONCLUSIONS

ESTEEM found no unexpected safety signals in older patients and annualized relapse rates (ARRs) were significantly reduced in both age groups. Both studies indicated that DMF is efficacious and has a favorable safety profile in patients with RRMS aged ≥ 50 years.

CLINICAL TRIAL REGISTRATION

ESTEEM (NCT02047097), PROCLAIM (NCT02525874).

A Practical Guide for Diagnostic Investigations and Special Considerations in Patients With Huntington's Disease in Korea

This review provides a comprehensive framework for the diagnostic approach and management of Huntington's disease (HD) tailored to the Korean population. Key topics include genetic counseling, predictive testing, and reproductive options like preimplantation genetic testing. Strategies for assessing disease progression in premanifest HD through laboratory investigations, biofluid, and imaging biomarkers are highlighted. Special considerations for juvenile and late-onset HD, along with associated comorbidities like diabetes mellitus, hypertension, and cardiovascular abnormalities, are discussed. The guide emphasizes personalized symptom management, including pharmacotherapy, physical therapy, and nutritional support, while exploring emerging disease-modifying treatments. A multidisciplinary care model is advocated to improve outcomes for HD patients and caregivers in Korea.

Blood and cerebrospinal fluid biomarkers in disorders of consciousness

The study of blood and cerebrospinal fluid biomarkers is a promising and rapidly advancing field in the research of disorders of consciousness (DoC). The use of advanced biochemical and analytic techniques in biomarker research has improved our ability to identify new biomarkers that can aid in the diagnosis, prognosis, and treatment of patients with brain injury. However, the use of biomarkers in clinical practice is limited by several challenges, including the lack of standardization in test and research methodologies. Despite this, identifying the most promising biomarkers and supporting their findings with strong evidence can improve their clinical utility. This chapter discusses the most promising biomarkers for DoC, which fall into four categories: neuronal, glial, inflammatory, and metabolic biomarkers. Understanding the role of each category in DoC can provide valuable insights into the mechanisms of brain injury and inform the development of more effective diagnostic and treatment strategies. By integrating biomarker research with clinical practice, we can improve our understanding of DoC and provide better care for these patients.

Neurofilament light and glial fibrillary acidic protein in mood and anxiety disorders: A systematic review and meta-analysis

Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) are biomarkers of neuronal injury measurable in cerebrospinal fluid (CSF) and blood. Despite their potential as diagnostic tests for neurodegenerative disorders, it is unclear how they behave in mood and anxiety disorders. We conducted a systematic review and meta-analysis to investigate whether NfL and GFAP concentrations were altered in adults with mood and anxiety disorders compared to healthy controls. We searched PubMed, Web of Science, PsycINFO, MEDLINE and Embase through August 20, 2024, and assessed relevant studies and their risk of bias. The primary outcome was the standardised mean difference (SMD) and 95 % confidence interval (95 % CI) of NfL and GFAP concentrations. Twenty-nine studies comprising 2,962 individuals (927majordepression,804bipolardisorder,and1,231controls). When we compared individuals with major depression and healthy controls, there was no difference in NfL nor GFAP levels. In individuals with bipolar disorder, NfL was significantly elevated compared to controls (SMD = 0.53; 95 % CI: 0.20, 0.85; p = 0.005). Only one study reported on NfL levels anxiety disorders. Our study informs clinicians about how to interpret these emerging biomarkers in determining whether a person's symptoms are caused by a neurodegenerative or mood disorder. The mild elevation of NfL in bipolar disorder may suggest underlying neuroaxonal injury, warranting further research into its clinical and prognostic significance.

Identification of RN7SK LncRNA as a novel biomarker in Alzheimer's disease using bioinformatics and expression analysis

Alzheimer's disease (AD) is a degenerative illness that accounts for the common type of dementia among adults over the age of 65. Despite extensive studies on the pathogenesis of the disease, early diagnosis of AD is still debatable. In this research, we performed bioinformatics approaches on the AD-related E-MTAB 6094 dataset to uncover new potential biomarkers for AD diagnosis. To achieve this, we performed in-depth in silico assays, including differentially expressed genes analysis, weighted gene co-expression network analyses, module-trait association analyses, gene ontology and pathway enrichment analyses, and hub genes network analyses. Finally, the expression of the identified candidate genes was evaluated in AD patients PBMC samples by qRT-PCR. Through computational analyses, we found that RN7SK LncRNA and its co-expressed genes of TNF, TNFAIP3, CCLT3, and FLT3 are from key genes in AD development that are associated with inflammatory responses. Our experimental validation revealed that RN7SK LncRNA and TNF were substantially up-regulated in AD samples (P = 0.006 and P = 0.023, respectively). Whereas, TNFAIP3 expression was significantly decreased (P = 0.016). However, the expression of CCL3 and FLT3 did not differ significantly between two groups (P = 0.396 and P = 0.521, respectively). In conclusion, in this study a novel LncRNA associated with AD pathogenesis were identified, which may provide new diagnostic biomarker for AD.

Serum neurofilament light chain levels in patients with small-fiber neuropathy

BACKGROUND

Serum neurofilament light chain (sNfL) levels are an increasingly employed tool for the assessment of active axonal injury in a variety of neurological disorders including polyneuropathy. Injury to the small nerve fibers can lead to small fiber neuropathy (SFN), a neurological condition which is clinically manifested by combination of burning pain, various sensory disturbances and symptoms of autonomic dysfunction. SFN is evident by identifying reduced epidermal nerve fiber density (ENFD) in skin biopsy.

OBJECTIVE

To assess the utility of sNfL measurement as a marker for active axonal injury in a population of patients who were referred for skin biopsy as part of the evaluation of chronic sensory symptoms.

METHODS

sNfL levels were measured in 94 patients at the time of skin biopsy. Clinical, electrodiagnostic, and imaging data were collected and neurological comorbidities including central nervous system disorders, large-fiber polyneuropathy, and radiculopathy which may increase sNfL levels were reviewed.

RESULTS

Eighty-six patients had pathological skin biopsy result supporting the diagnosis of SFN. sNfL was increased in 9 (10%) SFN patients. Seven of them had neurological comorbidities which may explain the elevated sNfL. The other two patients had history of hypothyroidism and endometriosis.

CONCLUSIONS

sNfL levels are typically normal in patients with SFN. Furthermore, when sNfL are elevated, evaluation for another neurological disorder should be considered.