Serum NfL Research Articles

Serum NfL as an MS biomarker.

Serum NfL as an MS biomarker.

Serum neurofilament light chain: a novel biomarker for early diabetic sensorimotor polyneuropathy

Aims/hypothesisNo established blood-based biomarker exists to monitor diabetic sensorimotor polyneuropathy (DSPN) and evaluate treatment response. The neurofilament light chain (NFL), a blood biomarker of neuroaxonal damage in several neurodegenerative diseases, represents a potential biomarker for DSPN. We hypothesised that higher serum NFL levels are associated with prevalent DSPN and nerve dysfunction in individuals recently diagnosed with diabetes.MethodsThis cross-sectional study included 423 adults with type 1 and type 2 diabetes and known diabetes duration of less than 1 year from the prospective observational German Diabetes Study cohort. NFL was measured in serum samples of fasting participants in a multiplex approach using proximity extension assay technology. DSPN was assessed by neurological examination, nerve conduction studies and quantitative sensory testing. Associations of serum NFL with DSPN (defined according to the Toronto Consensus criteria) were estimated using Poisson regression, while multivariable linear and quantile regression models were used to assess associations with nerve function measures. In exploratory analyses, other biomarkers in the multiplex panel were also analysed similarly to NFL.ResultsDSPN was found in 16% of the study sample. Serum NFL levels increased with age. After adjustment for age, sex, waist circumference, height, HbA1c, known diabetes duration, diabetes type, cholesterol, eGFR, hypertension, CVD, use of lipid-lowering drugs and use of non-steroidal anti-inflammatory drugs, higher serum NFL levels were associated with DSPN (RR [95% CI] per 1-normalised protein expression increase, 1.92 [1.50, 2.45], p<0.0001), slower motor (all p<0.0001) and sensory (all p≤0.03) nerve conduction velocities, lower sural sensory nerve action potential (p=0.0004) and higher thermal detection threshold to warm stimuli (p=0.023 and p=0.004 for hand and foot, respectively). There was no evidence for associations between other neurological biomarkers and DSPN or nerve function measures.Conclusions/interpretationOur findings in individuals recently diagnosed with diabetes provide new evidence associating higher serum NFL levels with DSPN and peripheral nerve dysfunction. The present study advocates NFL as a potential biomarker for DSPN.Graphical abstract

Evidence for and Against Subclinical Disease Activity and Progressive Disease in MOG Antibody Disease and Neuromyelitis Optica Spectrum Disorder

Objective To investigate the evidence for and against relapse-independent clinical progression and/or subclinical disease activity in patients with Myelin Oligodendrocyte Glycoprotein Antibody Disease (MOGAD) and Aquaporin-4 IgG Seropositive Neuromyelitis Optica Spectrum Disorder (AQP4-IgG+ NMOSD). Background MOGAD and AQP4-IgG+ NMOSD are generally relapsing disorders, without clinical progression or subclinical disease activity outside of relapses. With advances in the diagnosis and treatment of these conditions, prolonged periods of remission without relapses can be achieved, and the question of whether progressive disease courses can occur has re-emerged. Design/Methods We conducted a narrative literature review in Ovid MEDLINE and Embase, exploring the evidence for and against relapse-independent progression in MOGAD and AQP4-IgG+ NMOSD. We classified the results in four categories : 1)Clinical observations, 2)MRI findings, 3)Retinal imaging, and 4)Fluid-based biomarkers. Results As the optic nerve is the major site of involvement in MOGAD and AQP4-IgG+ NMOSD, much of the data comes from the visual pathway studies. Possible pathophysiologic mechanisms of the OCT abnormalities in the absence of symptomatic optic neuritis are: 1) primary neurodegenerative process in retina, 2) subclinical inflammation of the optic nerve, 3) chiasmal involvement leading to abnormal findings in the unaffected eye, and 4)trans-synaptic retrograde degeneration originating from inflammatory lesions in the posterior visual pathway. Except for chiasmal involvement, these mechanisms are not specific to the visual pathway, and are considered as potential explanations for subclinical disease activity outside of the retina. Outside of the visual pathway, there is a lack of sufficient evidence to support the existence of subclinical disease activity and/or relapse-independent clinical progression in MOGAD and AQP4-IgG+ NMOSD, although recent fluid-based biomarker data (serum NfL and GFAP) support that neuro-axonal and/or astrocytic damage may be ongoing between attacks in these diseases. Conclusions This review highlights the many unknowns that remain in our understanding of the pathophysiology and clinical course of MOGAD and AQP4-IgG+ NMOSD.

Angiotensin‐(1‐7)/Mas receptor agonist: a disease modifying therapeutic for VCID protects cognitive function and inhibits serum neurofilament light protein

AbstractBackgroundVascular contributions to cognitive impairment and dementia (VCID) and Alzheimer’s disease related dementias (ADRD) are associated with increases in systemic and brain inflammatory cytokines, increased reactive oxygen species (ROS) and decreased brain blood flow. We have completed preclinical development of novel synthetic glycopeptide derivatives of Angiotensin‐(1‐7) (Ang‐1‐7) MasR agonists that have outstanding brain penetration, improved half‐life, reverse cognitive impairment and decreases plasma neurofilament light protein (NfL) in our preclinical model of VCID. Ang‐(1‐7)/MasR mechanisms of action include inhibition of 1) microglia activation, 2) brain cytokines activation and, 3) vascular endothelial ROS production. The purpose of this pilot study was to 1) determine if plasma NfL is increased in coronary artery bypass graft (CABG) surgery patients at‐risk for VCID and 2) determine if treatment with an Ang‐(1‐7)/MasR agonist protects cognitive function post‐surgy and modifies NfL.MethodSubjects were randomly assigned to receive either 200 micrograms/kg/day s.c. (n = 3) or saline‐placebo (n = 2). Injections were begun 2 hours prior to surgery and then daily for 21 days. Cognitive function was measured prior to surgery and at 21‐ and 90‐days post‐surgery. Serum NfL was measured via Quanterix Simoa assay. Statistical analysis was performed using GraphPad and significance tested using Welch’s ANOVA, Dunnett’s post. Memory function was measured using a composite score comprised of memory, executive functioning, language, and processing speed.ResultPlasma levels of NfL prior to surgery were significantly increased by 176% in CABG patients (n = 5) as compared to age‐matched healthy controls (n = 8, p = .003). Treatment with Ang‐(1‐7) for 21‐days via subcutaneous injections protected memory function as measured by both the Face‐Name and Cured Name Retrieval associative memory tests at both 21‐ and 90‐days post ‐surgery and significantly attenuated CABG induced increases in NfL as compared to placebo‐saline treatment (p = .004).ConclusionThese preliminary data suggest that NfL may serve as a biomarker of VCID in CABG surgery patients and for MasR target engagement for VCID‐modifying treatments with Ang‐(1‐7) analogs. We have begun studies to develop NfL as a biomarker for Ang‐(1‐7)/MasR target activation and for patient stratification for treatment of VCID (Supported by NIH U01HL131014, U01AG066623).

Neurofilament light chain cannot be measured in urine to distinguish frontotemporal dementia with primary psychiatric diseases

AbstractBackgroundClinical overlap of the behavioral variant of FTD and primary psychiatric diseases (PPD) hampers diagnostic distinction, leading to frequent misdiagnosis and diagnostic delay. NfL in CSF and blood has shown great potential to accurately distinguish bvFTD from PPD and controls. Measurement of NfL in urine would be a minimal invasive, patient‐friendly biomarker assessment and thereby beneficial for future clinical implementation. We aimed to evaluate the diagnostic value of urine NfL concentration to distinguish bvFTD from PPD and controls and to assess if urine and serum NfL levels correlate.Method55 subjects (n = 19 FTD, n = 19 psychiatric patients: functional neurologic disorder n =2; obsessive compulsive disorder n= 1; unspecified mental disorder n =1; bipolar disorder, depressive phase n =1; depression, n = 6; adjustment disorder n = 3; anxiety disorder n = 1; autism spectrum disorder n =1; personality disorder n =2; somatic symptom disorder n = 2, and n = 17 controls) were included with available paired urine and serum samples. All subjects underwent standardized extensive diagnostic assessment. Samples were analyzed with the ultrasensitive SIMOA NfL assay. NfL group comparisons were performed adjusted for age and sex.ResultsIn the majority of the cohort NfL concentrations were not detectable in urine (n = 6 samples above lower limit of detection (0.038 pg/ml): n = 5 FTD, n =1 PPD). The frequency of a detectable NfL level in urine in the FTD (5/19) group did not differ from PPD (1/19); Fisher Exact‐test p = 0.180). In the individuals with detectable urine NfL values there was no correlation between the urine and serum NfL levels. As expected, serum NfL levels were higher in bvFTD compared to psychiatric patients and controls (p &lt; 0.000), adjusted for age and sex.ConclusionOur results implicate that using urine as matrix for NfL analysis is not suitable.

Serum NfL but not GFAP predicts cognitive decline in active progressive multiple sclerosis patients

Background: Cognitive decline is inadequately captured by the standard neurological examination. Serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) are biomarkers of neuronal damage and astrocytic reactivity that may offer an accessible measure of the multiple sclerosis (MS) pathology linked to cognitive decline. Objective: To investigate the association of sNfL and sGFAP with cognitive decline in MS patients at high risk for progressive pathology. Methods: We included 94 MS patients with sustained Expanded Disability Status Score (EDSS) ⩾ 3, available serum samples and cognitive assessment performed by symbol digit modalities test (SDMT) over a median of 3.1 years. The visit for sGFAP/sNfL quantification was at confirmed EDSS ⩾ 3. Linear regression analysis on log-transformed sGFAP/sNfL assessed the association with current and future SDMT. Analyses were adjusted for age, sex, EDSS, treatment group, and recent relapse. Results: sNfL was significantly associated with concurrent SDMT (adjusted change in mean SDMT = −4.5; 95% confidence interval (CI): −8.7, −0.2; p = 0.039) and predicted decline in SDMT (adjusted change in slope: −1.14; 95% CI: −1.83, −0.44; p = 0.001), particularly in active patients. sGFAP was not associated with concurrent or future SDMT. Conclusions: Higher levels of sNfL were associated with cognitive impairment and predicted cognitive decline in MS patients at high risk for having an underlying progressive pathology.

Longitudinal Changes in Blood Biomarkers of Clinical Alzheimer Disease in a Biracial Population Sample.

Recent studies suggest the utility of blood biomarkers in detecting changes in neurodegenerative disorders. The objective of our research was to test the hypothesis that the longitudinal changes in total tau (t-tau), neurofilament light chain (Nf-L), and glial fibrillary acidic protein (GFAP) are associated with structural MRI and the development of clinical Alzheimer disease (AD) and cognitive decline. Data came from a population-based sample with serum concentrations of t-tau, Nf-L, and GFAP and cognitive characteristics measured over 17 years. The inclusion criteria for this investigation were based on participants with blood samples, cognitive function testing, and clinical diagnosis for AD. The longitudinal changes in the serum biomarkers were examined using linear mixed models for log10-transformed concentrations. In 1,327 participants (60% Black participants and 60% women, the concentration of t-tau increased annually by 4.8% (95% CI = 4.0-5.6) and Nf-L by 5.9% (95% CI = 5.4-6.4). The longitudinal change in GFAP was higher among Black participants than among White participants (4.4% vs 3.5% per year, p = 0.028). Baseline MRI characteristics were associated with the longitudinal changes in serum biomarkers of clinical AD. Specifically, a higher baseline third ventricular volume was associated with a higher rate of increase in the concentration of t-tau, and white matter hyperintensities predicted a higher rate of increase in Nf-L. The rate of change in concentrations of t-tau, Nf-L, and GFAP was significantly higher among those who developed clinical AD than in those with no cognitive impairment. For each standard deviation unit decline in global cognition, longitudinal change in t-tau increased by 81% (95% CI = 76-86), Nf-L by 113% (95% CI = 105-120), and GFAP by 66% (95% CI = 62-70). Blood biomarkers showed significant longitudinal changes corresponding to cognitive decline, clinical AD, and structural MRI characteristics. Our findings show that longitudinal changes in serum biomarkers were associated with several cognitive endophenotypes. The study found Class II evidence that longitudinal changes in serum t-tau, Nf-L, and GFAP were associated with cognitive decline and the development of clinical AD in people older than 65 years.

Identification of Biomarkers As Predictors of Patient-Reported Outcomes in Persons with Multiple Sclerosis Given Autologous Hematopoietic Stem Cell Transplantation

Introduction: Around 80% of persons with multiple sclerosis (MS) have a positive patient-reported outcome (PRO) to autologous hematopoietic stem cell transplantation (aHSCT); this figure is better than that obtained with the novel immunossuppresive drugs. Objective: To identify markers for the appropriate selection of patients with multiple sclerosis who would benefit from aHSCT. Methods: We evaluated the levels of six biomarkes in the peripheral blood of patients with MS prior to aHSCT. Each biomarker was selected according to its possible role in MS: microRNAs (miR-146a, miR-155 and miR-326) as immune system alteration markers; interleukin 4 induced 1 (IL4I1) as remyelination marker; neurofilament light chain protein (NFL) as neuroaxonal damage marker; and the human leukocyte antigen (HLA) allele HLA-DRB1*15 as a MS risk marker. The design of this study is cross-sectional; sample was divided into two transplant response groups (responders and non-responders). The response to transplantation was assessed using the PRO (expanded disability status scale -EDSS) score, evaluated before aHSCT and one year later. Pre-transplant samples were used to identify the different markers. The techniques used for markers analysis were qPCR for microRNA measurement (miR-146a, miR155, miR326), SSP-PCR for HLA-DRB1*15, and immunoassay for IL4I1 and NFL Results: 34 patients were prospectively enrolled. 14 (41.2%) non-responders to transplantation (ΔEDSS < 0) and 20 (58.8%) with a positive response to transplantation (ΔEDSS > 0). The comparison made between the aHSCT PRO response groups, using the Mann-Whitney U statistical test, showed a statistically significant increase in the non-responder group in the following variables: hemoglobin (median = 14.9 vs median = 13.5) U = 81.5, p = .039; serum iron levels (median = 122.5 vs median = 91) U = 39, p =.04 and transferrin saturation (median = 33.94 vs median = 20.4) U = 30, p = .001. In addition, an increase in platelet count was observed in the good response group (median = 278.5 vs median = 229) U = 197.5, p = .043. Within the biomarkers evaluated, significant difference was only found in miR-146a levels, which showed an increase for the non-responder group (median = 6. 43 vs median = 3) U = 78, p = .03. We then performed a logistic regression analysis using the variables hemoglobin, serum iron levels, platelet count, miR146a, miR155, miR326, IL4I1 and NFL, to evaluate their predictive capacity in the response to transplantation. The logistic region model was configured to perform forward variable selection obtaining the following results: in the first step, 74.2% correct overall classification with the variable Iron; in the second step 82.8%, with the variables iron and hemoglobin; in the third step 89.7%, with the variables hemoglobin, serum iron levels and IL4I1; and in the third step 100%, with the variables hemoglobin, iron levels, IL4I1 and miR146a. Conclusions: Serum iron levels, hemoglobin levels, transferrin saturation and platelet count before aHSCT prior to transplantation show differences between PRO responders and non-responders to aHSCT; these variables coupled with the biomarkers IL4I1 and miR146a can be employed in predictive models of the PRO positive response to aHSCT in persons with MS.

Serum GFAP and NfL Levels Differentiate Subsequent Progression and Disease Activity in Patients With Progressive Multiple Sclerosis.

Neurodegeneration and astrocytic activation are pathologic hallmarks of progressive multiple sclerosis (MS) and can be quantified by serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP). We investigated sNfL and sGFAP as tools for stratifying patients with progressive MS based on progression and disease activity status. We leveraged our Comprehensive Longitudinal Investigation of MS at the Brigham and Women's Hospital (CLIMB) natural history study, which includes clinical, MRI data and serum samples collected over more than 20 years. We included patients with MS with a confirmed Expanded Disability Status Scale (EDSS) score ≥3 that corresponds with our classifier for patients at high risk of underlying progressive pathology. We analyzed sNfL and sGFAP within 6 months from the confirmed EDSS score ≥3 corresponding with our baseline visit. Patients who further developed 6-month confirmed disability progression (6mCDP) were classified as progressors. We further stratified our patients into active/nonactive based on new brain/spinal cord lesions or relapses in the 2 years before baseline or during follow-up. Statistical analysis on log-transformed sGFAP/sNfL assessed the baseline association with demographic, clinical, and MRI features and associations with future disability. We included 257 patients with MS who had an average EDSS score of 4.0 and a median follow-up after baseline of 7.6 years. sNfL was higher in patients with disease activity in the 2 years before baseline (adjusted β = 1.21; 95% CI 1.04-1.42; p = 0.016), during the first 2 years of follow-up (adjusted β = 1.17; 95% CI = 1.01-1.36; p = 0.042). sGFAP was not increased in the presence of disease activity. Higher sGFAP levels, but not sNfL levels, were associated with higher risk of 6mCDP (adjusted hazard ratio [HR] = 1.71; 95% CI = 1.19-2.45; p = 0.004). The association was stronger in patients with low sNfL (adjusted HR = 2.44; 95% CI 1.32-4.52; p = 0.005) and patients who were nonactive in the 2 years prior or after the sample. Higher levels of sGFAP correlated with subsequent progression, particularly in nonactive patients, whereas sNfL reflected acute disease activity in patients with MS at high risk of underlying progressive pathology. Thus, sGFAP and sNfL levels may be used to stratify patients with progressive MS for clinical research studies and clinical trials and may inform clinical care.

Neurofilament light chain: a promising diagnostic biomarker for functional motor disorders.

Functional motor disorders (FMDs) are disabling neurological conditions characterized by abnormal movements which are inconsistent and incongruent with recognized neurological diseases. Aim of this study is to investigate whether FMDs are related to structural axonal damage. Consecutive patients with a definite diagnosis of FMD with no other neurological/psychiatric comorbidities (pure FMDs) and age-matched healthy controls (HCs) were recruited in a tertiary center and demographic/clinical data were collected. Serum neurofilament light chain (NfL) assessment was performed with ultrasensitive paramagnetic bead-based enzyme-linked immunosorbent assay. 34 patients with FMDs and 34 HCs were included. NfL levels were similar (p = 0.135) in FMDs (median 8.3pg/mL, range 2-33.7) and HCs (median 6.1pg/mL, range 2.7-15.6). The area under curve (0.606, 95% CI 0.468-0.743) confirmed that NfL concentration was not different in the two groups. NfL values were similar in patients with paroxysmal vs persistent disease course (p = 0.301), and isolated vs combined symptoms (p = 0.537). NfL levels were associated with age (p < 0.0001), but not with disease duration (p = 0.425), number of CNS acting drugs (p = 0.850), or clinical features (p = 0.983). Our preliminary data show that NfL levels are similar in patients with FMDs and HCs, indicating the lack of neuroaxonal damage. These results have relevant pathogenic and clinical implications and suggest that serum NfL may be a promising diagnostic biomarker, potentially useful to differentiate functional vs structural neurological disorders.

Abstract 107: Systemic Allogeneic Mesenchymal Stem Cell Administration Does Not Attenuate Early Post-resuscitation Brain Injury Or Inflammation In A Porcine Model Of Cardiac Arrest

Introduction: Based on emerging evidence that systemic inflammation exacerbates post-resuscitation organ injury, we recently tested the efficacy of allogeneic mesenchymal stem cell (MSC) administration early after return of spontaneous circulation (ROSC) in a porcine model of cardiac arrest (CA). Initial results indicate that MSCs attenuate post-ROSC cardiac dysfunction, but it is unclear if these protective effects extend to the brain. Accordingly, we aimed to determine if systemic allogeneic MSCs reduce early post-ROSC brain injury and inflammation in swine. Methods: Swine (n=33) were subjected to 10 min CA followed by mechanical CPR with defibrillation and epinephrine (EPI; 0.015 mg/kg iv). Animals that achieved ROSC (n=19) were blindly randomized to intra-arterial saline (n=9) or allogeneic bone marrow-derived MSCs (55±2 x 10 6 ; n=10) 30 min post-ROSC. Blood sampling was performed for 4 hours post-ROSC to quantify serum neurofilament light chain (NFL) levels, after which brain tissue was collected for post-mortem quantification of regional neuronal injury (H&amp;E), activated microglia (IBA-1), and inflammatory gene expression (PCR) vs. healthy control swine (n=8). Results: Animals resuscitated from CA exhibited a significant increase in neuronal injury throughout the brain vs. controls that was not affected by MSC treatment ( A ). Similarly, the post-ROSC rise in serum NFL was not different between saline-treated and MSC-treated animals (2.5±0.6 vs. 2.5±0.8 fold-change vs. baseline; p=0.94). A significant increase in activated microglia ( B ) and inflammatory gene expression ( C ) was observed throughout the brain in both CA groups vs. healthy controls, with particularly prominent changes in the striatum but no notable differences between treatment groups. Conclusions: Despite favorable effects on the heart, systemic allogeneic MSC therapy after ROSC does not significantly affect early markers of brain injury and inflammation in a porcine model of CA.

Abstract 10581: Sustained Increase of Serum Glial Fibrillary Acidic Protein After First St-Elevation Myocardial Infarction

Introduction: Acute ischemic cardiac injury predisposes for cognitive impairment, dementia and depression. Beyond altered cerebral blood flow and neurohumoral activation, recent positron emission tomography data pathophysiologically suggest acute and chronic neuroinflammation, which is accompanied by astroglial activation, after acute experimental myocardial infarction (MI). Hypothesis: Peripheral serum biomarkers indicating neuronal and glial involvement are altered in the year after first acute MI. Methods: Within the investigator-initiated, prospective, multicenter diagnostic ETiCS study, we quantified serum levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) using ultra-sensitive molecular immunoassays serially in the year after first ST-elevation MI (STEMI). Cardiac magnetic resonance imaging enabled precise detection of infarction volume and ejection fraction. Results: Sufficient biomaterial was available from 45 STEMI patients (aged 28 to 78 years, median 56 years, 11% female). Median serum NfL (quartiles) at hospital admission was 10.6 (7.2, 14.8 pg/ml) and median GFAP 63.8 (47.0, 89.9 pg/ml). Absolute levels of NfL (ρ=0.78; p&lt;0.001) and GFAP (ρ=0.56; p&lt;0.001) correlated to patient age at all time-points. While NfL remained unaltered in the course of one year, GFAP after STEMI increased in the first 3 months after MI with a mean change of +10.6±25.0 pg/ml (p=0.007), and remained elevated after 6 months (+12.4±32.9 pg/ml; p=0.015) and 12 months (+12.6±31.2 pg/ml; p=0.010) compared to baseline. Larger relative infarction volume (ρ=0.41; p=0.009) and higher peak creatine kinase levels (ρ=0.39; p&lt;0.001), but not ejection fraction, correlated to increases of GFAP and NfL, respectively. Conclusions: Our findings suggest subtle glial damage after STEMI which correlates to infarction volume. Further studies need to evaluate the valence of serum GFAP as a peripheral biomarker of cognitive decline after MI.

Serum Neurofilament Light Chain and Glial Fibrillary Acidic Protein as Biomarkers in Primary Progressive Multiple Sclerosis and Hereditary Spastic Paraplegia Type 4.

In patients with slowly progressive spastic paraparesis, the differential diagnosis of primary progressive multiple sclerosis (PPMS) and hereditary spastic paraplegia (HSP) can be challenging. Serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) are promising fluid biomarkers to support the diagnostic workup. Serum NfL is a marker of neuroaxonal decay sensitive to temporal changes, while elevated sGFAP levels may reflect astrocytal involvement in PPMS. We assessed sNfL and sGFAP levels in 25 patients with PPMS, 25 patients with SPG4 (the most common type of HSP) and 60 controls, using the highly sensitive single-molecule array (Simoa) platform. Patients were matched in age, sex, age at onset, disease duration and disease severity. Serum NfL levels were significantly increased in PPMS compared to SPG4 (p = 0.041, partial η² = 0.088), and there was a trend toward relatively higher sGFAP levels in PPMS (p = 0.097). However, due to overlapping biomarker values in both groups, we did not find sNfL and sGFAP to be useful as differential biomarkers in our cohort. The temporal dynamics indicate sNfL and sGFAP levels are most markedly elevated in PPMS in earlier disease stages, supporting their investigation in this group most in need of a diagnostic biomarker.

An innovative approach for the evaluation of prolonged disorders of consciousness using NF-L and GFAP biomarkers: a pivotal study

Behavioral assessments during the clinical evaluation in prolonged disorders of consciousness patients could be not sufficient for a correct diagnosis and prognostication. To this aim, we used an innovative approach, involving the ultra-sensitive determination of biological markers, correlating them with imaging parameters to investigate the prolonged disorders of consciousness (pDoC).We assessed the serum concentration of neurofilament light chain(NF-L) and glial fibrillary acidic protein (GFAP) in pDoC (n = 16), and healthy controls (HC, n = 6) as well as several clinical imaging parameters such as Fractional Anisotropy (FA), Whole Brain SUV, and White Matter Hyperintensities volumes (WMH) using PET-MRI acquisition. As for differential diagnosis task, only the imaging WMH volume was able to discriminate between vegetative state/unresponsive wakefulness syndrome (VS/UWS), and minimally conscious state (MCS) patients (p-value < 0.01), while all selected markers (both imaging and in vitro) were able to differentiate between pDoC patients and HC. At subject level, serum NF-L concentrations significantly differ according to clinical progression and consciousness recovery (p-value < 0.01), highlighting a potential play for the longitudinal management of these patients.

Neurological symptoms and neuronal damage markers in acute COVID-19: Is there a correlation? A pilot study.

A wide spectrum of neurological symptoms (NS) has been described in patients with COVID-19. We examined the plasma levels of neuron-specific enolase (NSE) and neurofilament light chain (NFL) together, as neuronal damage markers, and their relationships with clinical severity in patients with NS at acute COVID-19.A total of 20 healthy controls and 59 patients with confirmed COVID-19 were enrolled in this pilot prospective study. Serum NSE and NFL levels were measured by using the enzyme-linked immunoassay method from serum samples.Serum NSE levels were found to be significantly higher in the severe group than in the nonsevere group (p = 0.034). However, serum NFL levels were similar between the control and disease groups (p > 0.05). For the mild group, serum NFL levels were significantly higher in patients with the sampling time ≥5 days than in those with the sampling time <5 days (p = 0.019). However, no significant results for NSE and NFL were obtained in patients with either single or multiple NS across the groups (p > 0.05).Increased serum NSE levels were associated with disease severity regardless of accompanied NS in patients with acute COVID-19 infection. However, serum NFL levels may have a role at the subacute phase of COVID-19.

Neurofilament Light Chain Levels Are Predictive of Clinical Conversion in Radiologically Isolated Syndrome.

To evaluate the predictive value of serum neurofilament light chain (sNfL) and CSF NfL (cNfL) in patients with radiologically isolated syndrome (RIS) for evidence of disease activity (EDA) and clinical conversion (CC). sNfL and cNfL were measured at RIS diagnosis by single-molecule array (Simoa). The risk of EDA and CC according to sNfL and cNfL was evaluated using the Kaplan-Meier analysis and multivariate Cox regression models including age, spinal cord (SC) or infratentorial lesions, oligoclonal bands, CSF chitinase 3-like protein 1, and CSF white blood cells. Sixty-one patients with RIS were included. At diagnosis, sNfL and cNfL were correlated (Spearman r = 0.78, p < 0.001). During follow-up, 47 patients with RIS showed EDA and 36 patients showed CC (median time 12.6 months, 1-86). When compared with low levels, medium and high cNfL (>260 pg/mL) and sNfL (>5.0 pg/mL) levels were predictive of EDA (log rank, p < 0.01 and p = 0.02, respectively). Medium-high cNfL levels were predictive of CC (log rank, p < 0.01). In Cox regression models, cNfL and sNfL were independent factors of EDA, while SC lesions, cNfL, and sNfL were independent factors of CC. cNfL >260 pg/mL and sNfL >5.0 pg/mL at diagnosis are independent predictive factors of EDA and CC in RIS. Although cNfL predicts disease activity better, sNfL is more accessible than cNfL and can be considered when a lumbar puncture is not performed. This study provides Class II evidence that in people with radiologic isolated syndrome (RIS), initial serum and CSF NfL levels are associated with subsequent evidence of disease activity or clinical conversion.

Metabolomics detects clinically silent neuroinflammatory lesions earlier than neurofilament-light chain in a focal multiple sclerosis animal model

BackgroundDespite widespread searches, there are currently no validated biofluid markers for the detection of subclinical neuroinflammation in multiple sclerosis (MS). The dynamic nature of human metabolism in response to changes in homeostasis, as measured by metabolomics, may allow early identification of clinically silent neuroinflammation. Using the delayed-type hypersensitivity (DTH) MS rat model, we investigated the serum and cerebrospinal fluid (CSF) metabolomics profiles and neurofilament-light chain (NfL) levels, as a putative marker of neuroaxonal damage, arising from focal, clinically silent neuroinflammatory brain lesions and their discriminatory abilities to distinguish DTH animals from controls.Methods1H nuclear magnetic resonance (NMR) spectroscopy metabolomics and NfL measurements were performed on serum and CSF at days 12, 28 and 60 after DTH lesion initiation. Supervised multivariate analyses were used to determine metabolomics differences between DTH animals and controls. Immunohistochemistry was used to assess the extent of neuroinflammation and tissue damage.ResultsSerum and CSF metabolomics perturbations were detectable in DTH animals (vs. controls) at all time points, with the greatest change occurring at the earliest time point (day 12) when the neuroinflammatory response was most intense (mean predictive accuracy [SD]—serum: 80.6 [10.7]%, p < 0.0001; CSF: 69.3 [13.5]%, p < 0.0001). The top discriminatory metabolites at day 12 (serum: allantoin, cytidine; CSF: glutamine, glucose) were all reduced in DTH animals compared to controls, and correlated with histological markers of neuroinflammation, particularly astrogliosis (Pearson coefficient, r—allantoin: r = − 0.562, p = 0.004; glutamine: r = − 0.528, p = 0.008). Serum and CSF NfL levels did not distinguish DTH animals from controls at day 12, rather, significant differences were observed at day 28 (mean [SEM]—serum: 38.5 [4.8] vs. 17.4 [2.6] pg/mL, p = 0.002; CSF: 1312.0 [379.1] vs. 475.8 [74.7] pg/mL, p = 0.027). Neither serum nor CSF NfL levels correlated with markers of neuroinflammation; serum NfL did, however, correlate strongly with axonal loss (r = 0.641, p = 0.001), but CSF NfL did not (p = 0.137).ConclusionsWhile NfL levels were elevated later in the pathogenesis of the DTH lesion, serum and CSF metabolomics were able to detect early, clinically silent neuroinflammation and are likely to present sensitive biomarkers for the assessment of subclinical disease activity in patients.

Serum Neurofilament Light in Neurosyphilis: A Pilot Study.

Background Lumbar puncture is recommended for individuals with syphilis who have neurological symptoms; however, symptoms have poor sensitivity for predicting symptomatic neurosyphilis. Neurofilament light chain (NfL) is a marker for neuroaxonal injury; cerebrospinal fluid concentrations are higher in symptomatic neurosyphilis than in uncomplicated syphilis or asymptomatic neurosyphilis. Methods Serum NfL was quantified in 20 individuals with uncomplicated syphilis, 10 with asymptomatic neurosyphilis and 10 with symptomatic neurosyphilis using an ultrasensitive single-molecule array assay; it was repeated a median of 12.5 months after neurosyphilis therapy. Serum NfL concentration was age-adjusted using a published formula. Results Age-adjusted serum NfL concentration was significantly higher in symptomatic neurosyphilis compared with each of the other 2 groups. It was above the highest value in uncomplicated syphilis in 1 of 10 participants with asymptomatic neurosyphilis and 3 of 10 with symptomatic neurosyphilis. Serum NfL concentration increased in 1 participant with asymptomatic neurosyphilis with possible treatment failure. Conclusions If confirmed in a larger study, serum NfL may be a useful adjunct for identifying central nervous system infection by Treponema pallidum.

Serum neurofilament light chain levels are correlated with the infarct volume in patients with acute ischemic stroke.

Neurofilament light chains (NfLs) are promising biomarkers of neuroaxonal damage in stroke patients. We investigated the correlations between NfL levels and infarct volume, initial stroke severity, and functional outcomes at discharge in patients with acute ischemic stroke.We prospectively included 15 patients with first-ever acute ischemic stroke and 8 age- and sex-matched healthy controls without other neurological disorders. Serum NfL levels were measured using the single-molecule array (Simoa) technique twice within 24 hours of admission (NfL1D) and on the seventh hospital day (NfL7D) in patients with stroke and once in healthy controls. We assessed the infarct volume on diffusion-weighted magnetic resonance imaging using the free software ITK-SNAP.Serum NfL1D levels in stroke patients were significantly higher (28.4 pg/mL; interquartile range [IQR], 43.0) than in healthy controls (14.5 pg/mL; IQR, 3.2; P = .005). Temporal pattern analyses demonstrated that NfL7D levels were increased (114.0 pg/mL; IQR, 109.6) compared to NfL1D levels in all stroke patients (P = .001). There was a strong correlation between NfL7D levels and infarct volume (R = 0.67, P = .007). The difference between NfL1D and NfL7D (NfLdiff levels) was strongly correlated with the infarct volume (R = 0.63; P = .013). However, there was no statistically significant correlation between NfL levels and the initial stroke severity or functional outcomes at discharge.NfL levels in the subacute stage of stroke and the NfL difference between admission and 7th day of hospital were correlated with infarct volume in patients with acute ischemic stroke.

Serum glial fibrillary acidic protein and neurofilament light chain in patients with early treated phenylketonuria.

To pave the way for healthy aging in early treated phenylketonuria (ETPKU) patients, a better understanding of the neurological course in this population is needed, requiring easy accessible biomarkers to monitor neurological disease progression in large cohorts. The objective of this pilot study was to investigate the potential of glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) as blood biomarkers to indicate changes of the central nervous system in ETPKU. In this single-center cross-sectional study, GFAP and NfL concentrations in serum were quantified using the Simoa® multiplex technology in 56 ETPKU patients aged 6–36 years and 16 age matched healthy controls. Correlation analysis and hierarchical linear regression analysis were performed to investigate an association with disease-related biochemical parameters and retinal layers assessed by optical coherence tomography. ETPKU patients did not show significantly higher GFAP concentrations (mean 73 pg/ml) compared to healthy controls (mean 60 pg/ml, p = 0.140). However, individual pediatric and adult ETPKU patients had GFAP concentrations above the healthy control range. In addition, there was a significant association of GFAP concentrations with current plasma tyrosine concentrations (r = −0.482, p = 0.036), a biochemical marker in phenylketonuria, and the retinal inner nuclear layer volume (r = 0.451, p = 0.04). There was no evidence of NfL alterations in our ETPKU cohort. These pilot results encourage multicenter longitudinal studies to further investigate serum GFAP as a complementary tool to better understand and monitor neurological disease progression in ETPKU. Follow-up investigations on aging ETPKU patients are required to elucidate the potential of serum NfL as biomarker.