Levels of phosphorylated axonal neurofilament subunit H (pNfH) are increased in acute ischemic stroke

Advances in development of biomarkers for brain damage and ischemia

Acquired brain injury is an urgent situation that requires rapid diagnosis and treatment. Magnetic resonance imaging (MRI) and computed tomography (CT) are required for accurate diagnosis. However, these methods are costly and require substantial infrastructure and specialized staff. Circulatory biomarkers of acute brain injury may help in the management of patients with acute cerebrovascular events and prevent poor outcome and mortality. The purpose of this review is to provide an overview of the development of potential biomarkers of brain damage to increase diagnostic possibilities. For this purpose, we searched the PubMed database of studies on the diagnostic potential of brain injury biomarkers. We also accessed information from Clinicaltrials.gov to identify any clinical trials of biomarker measurements for the diagnosis of brain damage. In total, we present 41 proteins, enzymes and hormones that have been considered as biomarkers for brain injury, of which 20 have been studied in clinical trials. Several microRNAs have also emerged as potential clinical biomarkers for early diagnosis. Combining multiple biomarkers in a panel, along with other parameters, is yielding promising outcomes.

Fluid biomarkers of the neurovascular unit in cerebrovascular disease and vascular cognitive disorders: A systematic review and meta-analysis

Background

The disruption of the neurovascular unit (NVU), which maintains the integrity of the blood brain barrier (BBB), has been identified as a critical mechanism in the development of cerebrovascular and neurodegenerative disorders. However, the understanding of the pathophysiological mechanisms linking NVU dysfunction to the disorders is incomplete, and reliable blood biomarkers to measure NVU dysfunction are yet to be established. This systematic review and meta-analysis aimed to identify biomarkers associated with BBB dysfunction in large vessel disease, small vessel disease (SVD) and vascular cognitive disorders (VCD).

Methods

A literature search was conducted in PubMed, EMBASE, Scopus and PsychINFO to identify blood biomarkers related to dysfunction of the NVU in disorders with vascular pathologies published until 20 November 2023. Studies that assayed one or more specific markers in human serum or plasma were included. Quality of studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. Effects were pooled and methodological heterogeneity examined using the random effects model.

Results

A total of 112 studies were included in this review. Where study numbers allowed, biomarkers were analysed using random effect meta-analysis for VCD (1 biomarker; 5 studies) and cerebrovascular disorders, including stroke and SVD (9 biomarkers; 29 studies) while all remaining biomarkers (n = 17 biomarkers; 78 studies) were examined through qualitative analysis. Results of the meta-analysis revealed that cerebrospinal fluid/serum albumin quotient (Q-Alb) reliably differentiates VCD patients from healthy controls (MD = 2.77; 95 % CI = 1.97-3.57; p < 0.0001) while commonly measured biomarkers of endothelial dysfunction (VEGF, VCAM-1, ICAM-1, vWF and E-selectin) and neuronal injury (NfL) were significantly elevated in vascular pathologies. A qualitative assessment of non-meta-analysed biomarkers revealed NSE, NfL, vWF, ICAM-1, VCAM-1, lipocalin-2, MMP-2 and MMP-9 levels to be upregulated in VCD, although these findings were not consistently replicated.

Conclusions

This review identifies several promising biomarkers of NVU dysfunction which require further validation. A panel of biomarkers representing multiple pathophysiological pathways may offer greater discriminative power in distinguishing possible disease mechanisms of VCD.

Analysis of Serum Markers of Perioperative Brain Injury and Inflammation Associated with Endovascular Treatment of Intracranial Aneurysms: A Preliminary Study

Embolization is the preferred method for treating intracranial aneurysms due to its less invasive nature. However, recent findings suggest that even uncomplicated embolization may cause structural damage to the brain through ischemic or inflammatory mechanisms. This study aimed to find possible biomarkers of brain injury and inflammation in patients suffering from intracranial aneurysms who underwent endovascular treatment by measuring serological markers indicating brain damage. The study involved 26 patients who underwent uncomplicated intravascular stenting for unruptured intracranial aneurysms between January 2020 and December 2021. Blood samples were collected before the procedure, at 6-12 h, and at 24 h after the procedure. The following protein biomarkers levels were tested with ELISA: S100B, hNSE, TNF, hsCRP, FABP7, NFL, and GP39. Statistical analysis of the results revealed significant increases in serum levels for the four biomarkers: FABP7-before 0.25 (ng/mL) vs. 6-12 h 0.26 (p = 0.012) and vs. 24 h 0.27 (p < 0.001); GP39-before 0.03 (pg/mL) vs. 6-12 h 0.64 (p = 0.011) and vs. 24 h 0.57 (p = 0.001); hsCRP-before 1.65 (μg/mL) vs. 24 h 4.17 (p = 0.037); NFL-before 0.01 (pg/mL) vs. 6-12 h 3.99 (p = 0.004) and vs. 24 h 1.86 (p = 0.033). These biomarkers are recognized as potential indicators of neurovascular damage and should be monitored in clinical settings. Consequently, serum levels of NFL, GP39, hsCRP, and FABP7 measured before and 24 h after endovascular procedures can serve as important markers for assessing brain damage and indicate avenues for further research on biomarkers of neurovascular injury.

Plasma Glial Fibrillary Acidic Protein and N-Terminal Pro B-Type Natriuretic Peptide: Potential Biomarkers to Differentiate Ischemic and Hemorrhagic Stroke

Acute stroke management is critically time-sensitive and challenging. Blood-based biomarkers that can differentiate acute ischemic stroke (IS) from hemorrhagic stroke (HS) can greatly facilitate triage and early management. Admission blood samples obtained within 6 h of stroke symptom onset were analyzed in a derivation/validation design. GFAP, N-FL, NT-proBNP, copeptin, neutrophils (%), NLR, and platelet counts were assessed in the derivation cohort. The informative markers and the derived cutoff values were evaluated in the validation cohort. GFAP > 703 pg/mL showed a PPV of 76.9% and NPV of 95.8% for differentiating HS from IS. Multiple logistic regression analysis showed that GFAP and NT-proBNP were independent variables associated with IS and HS differentiation. Furthermore, applying a combined cutoff (GFAP > 703 pg/mL and NT-proBNP ≤ 125 pg/mL) for HS detection increased the PPV in both the derivation and validation cohorts (93.3% and 100%, respectively). GFAP and NT-proBNP levels were validated as informative blood biomarkers in the differentiation of IS and HS and using a combination of GFAP and NT-proBNP is suggested as a feasible strategy to differentiate stroke subtypes in the hyperacute phase of stroke.

Early assessment of aspiration risk in acute stroke by fiberoptic endoscopy in critically ill patients

Background

Fiberoptic endoscopic evaluation of swallowing (FEES) has been recommended to assess aspiration in stroke. This study aimed to determine the diagnostic and prognostic roles of FEES in the early assessment of aspiration, intensive care unit (ICU) stay and mortality in acute stroke patients.

Methods

Fifty-two patients with acute stroke admitted to the Alexandria Main University Hospital were included. Complete examinations and assessment of aspiration using the 8-point penetration-aspiration scale (PAS) with FEES protocol were performed.

Results

The patients were classified into three groups: normal with no or low risk of aspiration (n=15, 27.3%; PAS level 1), low to moderate risk (n=8, 14.5%; PAS level 2–4), and high risk (n=32, 58.2%; PAS ≥5). There was high incidence of aspiration pneumonia, prolonged ICU stay, and mortality in both moderate- and high-risk groups (P=0.001, P<0.001, and P<0.001, respectively). The PAS score predicted aspiration pneumonia (hospital-acquired pneumonia) with sensitivity and specificity of 80.0% and 76.0%, respectively (negative predictive value [NPV], 76.0; positive predictive value [PPV], 80.0; 95% confidence interval [CI], 0.706–0.940) and mortality with sensitivity and specificity of 88.46% and 68.97% (NPV, 87.0; PPV, 71.9; 95% CI, 0.749–0.951). The PAS score could predict the length of ICU stay with sensitivity and specificity of 70.21% and 87.50, respectively (NPV, 33.3; PPV, 97.1; 95% CI, 0.605–0.906).

Conclusions

The standard FEES protocol using PAS score is a useful tool to assess aspiration in acute stroke patients and could be used to predict length of ICU stay and mortality.

Long-Term Cognitive Dysfunction in Cancer Survivors

Cancer-related cognitive impairment (CRCI) is a frequent side effect experienced by an increasing number of cancer survivors with a significant impact on their quality of life. Different definitions and means of evaluation have been used in available literature; hence the exact incidence of CRCI remains unknown. CRCI can be described as cognitive symptoms reported by cancer patients in self-reported questionnaires or as cognitive changes evaluated by formal neuropsychological tests. Nevertheless, association between cognitive symptoms and objectively assessed cognitive changes is relatively weak or absent. Studies have focused especially on breast cancer patients, but CRCI has been reported in multiple types of cancer, including colorectal, lung, ovarian, prostate, testicular cancer and hematological malignancies. While CRCI has been associated with various treatment modalities, including radiotherapy, chemotherapy, hormone therapy and novel systemic therapies, it has been also detected prior to cancer treatment. Therefore, the effects of cancer itself with or without the psychological distress may be involved in the pathogenesis of CRCI as a result of altered coping mechanisms after cancer diagnosis. The development of CRCI is probably multifactorial and the exact mechanisms are currently not completely understood. Possible risk factors include administered treatment, genetic predisposition, age and psychological factors such as anxiety, depression or fatigue. Multiple mechanisms are suggested to be responsible for CRCI, including direct neurotoxic injury of systemic treatment and radiation while other indirect contributing mechanisms are hypothesized. Chronic neuroinflammation mediated by active innate immune system, DNA-damage or endothelial dysfunction is hypothesized to be a central mechanism of CRCI pathogenesis. There is increasing evidence of potential plasma (e.g., damage associated molecular patterns, inflammatory components, circulating microRNAs, exosomes, short-chain fatty acids, and others), cerebrospinal fluid and radiological biomarkers of cognitive dysfunction in cancer patients. Discovery of biomarkers of cognitive impairment is crucial for early identification of cancer patients at increased risk for the development of CRCI or development of treatment strategies to lower the burden of CRCI on long-term quality of life. This review summarizes current literature on CRCI with a focus on long-term effects of different cancer treatments, possible risk factors, mechanisms and promising biomarkers.

Neurofilament Proteins as Biomarkers to Monitor Neurological Diseases and the Efficacy of Therapies

Biomarkers of neurodegeneration and neuronal injury have the potential to improve diagnostic accuracy, disease monitoring, prognosis, and measure treatment efficacy. Neurofilament proteins (NfPs) are well suited as biomarkers in these contexts because they are major neuron-specific components that maintain structural integrity and are sensitive to neurodegeneration and neuronal injury across a wide range of neurologic diseases. Low levels of NfPs are constantly released from neurons into the extracellular space and ultimately reach the cerebrospinal fluid (CSF) and blood under physiological conditions throughout normal brain development, maturation, and aging. NfP levels in CSF and blood rise above normal in response to neuronal injury and neurodegeneration independently of cause. NfPs in CSF measured by lumbar puncture are about 40-fold more concentrated than in blood in healthy individuals. New ultra-sensitive methods now allow minimally invasive measurement of these low levels of NfPs in serum or plasma to track disease onset and progression in neurological disorders or nervous system injury and assess responses to therapeutic interventions. Any of the five Nf subunits - neurofilament light chain (NfL), neurofilament medium chain (NfM), neurofilament heavy chain (NfH), alpha-internexin (INA) and peripherin (PRPH) may be altered in a given neuropathological condition. In familial and sporadic Alzheimer's disease (AD), plasma NfL levels may rise as early as 22 years before clinical onset in familial AD and 10 years before sporadic AD. The major determinants of elevated levels of NfPs and degradation fragments in CSF and blood are the magnitude of damaged or degenerating axons of fiber tracks, the affected axon caliber sizes and the rate of release of NfP and fragments at different stages of a given neurological disease or condition directly or indirectly affecting central nervous system (CNS) and/or peripheral nervous system (PNS). NfPs are rapidly emerging as transformative blood biomarkers in neurology providing novel insights into a wide range of neurological diseases and advancing clinical trials. Here we summarize the current understanding of intracellular NfP physiology, pathophysiology and extracellular kinetics of NfPs in biofluids and review the value and limitations of NfPs and degradation fragments as biomarkers of neurodegeneration and neuronal injury.

Plasma neurofilament light predicts mortality in patients with stroke

Given the heterogeneity of stroke brain injury, there is a clear need for a biomarker that determines the degree of neuroaxonal injury across stroke types. We evaluated whether blood neurofilament light (NFL) would fulfill this purpose for patients with acute cerebral infarction (ACI; N = 227), aneurysmal subarachnoid hemorrhage (aSAH; N = 58), or nontraumatic intracerebral hemorrhage (ICH; N = 29). We additionally validated our findings in two independent cohorts of patients with ICH (N = 96 and N = 54) given the scarcity of blood biomarker studies for this deadliest stroke type. Compared to healthy individuals (N = 79 and N = 48 for the discovery and validation cohorts, respectively), NFL was higher for all stroke types. NFL associated with radiographic markers of brain tissue damage. It correlated with the extent of early ischemic injury in patients with ACI, hemorrhage severity in patients with aSAH, and intracranial hemorrhage volume in patients with ICH. In all patients, NFL independently correlated with scores from the NIH Stroke Scale, the modified Rankin Scale, and the Mini-Mental State Examination at blood draw, which respectively assess neurological, functional, and cognitive status. Furthermore, higher NFL concentrations independently associated with 3- or 6-month functional disability and higher all-cause mortality. These data support NFL as a uniform method to estimate neuroaxonal injury and forecast mortality regardless of stroke mechanism. As a prognostic biomarker, blood NFL has the potential to assist with planning supportive and rehabilitation services and improving clinical trial efficiency for stroke therapeutics and devices.

Neurofilament Proteins as Prognostic Biomarkers in Neurological Disorders

Neurofilaments: light, medium, and heavy (abbreviated as NF-L, NF-M, and NF-H, respectively), which belong to Type IV intermediate filament family (IF), are neuron-specific cytoskeletal components. Neurofilaments are axonal structural components and integral components of synapses, which are important for neuronal electric signal transmissions along the axons and post-translational modification. Abnormal assembly of neurofilaments is found in several human neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), infantile spinal muscular atrophy (SMA), and hereditary sensory-motor neuropathy (HSMN). In addition, those pathological neurofilament accumulations are known in α-synuclein in Parkinson's disease (PD), Aβ and tau in Alzheimer's disease (AD), polyglutamine in CAG trinucleotide repeat disorders, superoxide dismutase 1 (SOD1), TAR DNA-binding protein 43 (TDP43), neuronal FUS proteins, optineurin (OPTN), ubiquilin 2 (UBQLN2), and dipeptide repeat protein (DRP) in amyotrophic lateral sclerosis (ALS). When axon damage occurs in central nervous disorders, neurofilament proteins are released and delivered into cerebrospinal fluid (CSF), which are then circulated into blood. New quantitative analyses and assay techniques are well-developed for the detection of neurofilament proteins, particularly NF-L and the phosphorylated NF-H (pNF-H) in CSF and serum. This review discusses the potential of using peripheral blood NF quantities and evaluating the severity of damage in the nervous system. Intermediate filaments could be promising biomarkers for evaluating disease progression in different nervous system disorders.

Risk Factors for Delayed Neurocognitive Recovery According to Brain Biomarkers and Cerebral Blood Flow Velocity

Background and Objectives: The aim of this study is to identify risk factors for the development of delayed neurocognitive recovery (dNCR). Methods: 140 patients underwent neurocognitive evaluations (Adenbrooke, MoCa, trial making, and CAM test) and middle cerebral artery (MCA) blood flow velocity (BFV) measurements, one day before cardiac surgery. BFV was re-evaluated after anesthesia induction, before the beginning, middle, end, and after cardiopulmonary bypass (CPB) and postsurgery. To measure glial fibrillary acidic protein (GFAP) and neurofilament heavy chain (Nf-H), blood samples were collected after anesthesia induction, 24 and 48 h after the surgery. Neurocognitive evaluation was repeated 7-10 days after surgery. According to the results, patients were divided into two groups: with dNCR (dNCR group) and without dNCR (non-dNCR group). Results: 101 patients completed participation in this research. GFAP increased in both the non-dNCR group (p < 0.01) and in the dNCR group (p < 0.01), but there was no difference between the groups (after 24 h, p 0.342; after 48 h, p 0.273). Nf-H increased in both groups (p < 0.01), but there was no difference between them (after 24 h, p = 0.240; after 48 h, p = 0.597). MCA BFV was significantly lower in the dNCR group during the bypass (37.13 cm/s SD 7.70 versus 43.40 cm/s SD 9.56; p = 0.001) and after surgery (40.54 cm/s SD 11.21 versus 47.6 cm/s SD 12.01; p = 0.003). Results of neurocognitive tests correlated with CO₂ concentration (Pearson's r 0.40, p < 0.01), hematocrit (r 0.42, p < 0.01), MCA BFV during bypass (r 0.41, p < 0.01), and age (r -0.533, p < 0.01). The probability of developing dNCR increases 1.21 times with every one year of increased age (p < 0.01). The probability of developing dNCR increases 1.07 times with a decrease of BFV within 1 cm/s during bypass (p = 0.02). Conclusion: Risk factors contributing to dNCR among the tested patients were older age and middle cerebral artery blood flow velocity decrease during bypass.

Acute Neurofilament Light Chain Plasma Levels Correlate With Stroke Severity and Clinical Outcome in Ischemic Stroke Patients

Background: Ischemic stroke causes increased blood–brain barrier permeability and release of markers of axonal damage and inflammation. To investigate diagnostic and prognostic roles of neurofilament light chain (NF-L), we assessed levels of NF-L, S100B, interleukin-6 (IL-6), E-selectin, vascular endothelial growth factor-A (VEGF-A), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in patients with acute ischemic stroke or transient ischemic attack (TIA) and healthy controls.

Methods: We studied neurofilament (NF) expression in 2 cases of human postmortem ischemic stroke, representing infarcts aged 3- to >7-days. In a prospective study, we measured plasma NF-L and inflammatory markers <8 h of symptom onset and at 72 h in acute ischemic stroke (n = 31), TIA (n = 9), and healthy controls (n = 29). We assessed whether NF-L, S100B, and IL-6 were associated with clinical severity on admission (Scandinavian Stroke Scale, SSS), diagnosis of ischemic stroke vs. TIA, and functional outcome at 3 months (modified Rankin Scale, mRS).

Results: NF expression increased in ischemic neurons and in the infarcted brain parenchyma after stroke. Plasma NF-L levels were higher in stroke patients than in TIA patients and healthy controls, but IL-6 levels were similar. Higher acute NF-L levels were associated with lower SSS scores at admission and higher mRS scores at 3 months. No correlation was observed between NF-L and S100B, NF-L and IL-6, nor between S100B or IL-6 and SSS or mRS. Compared to controls, stroke patients had significantly higher VEGF-A and VCAM-1 at <8 h that remained elevated at 72 h, with significantly higher VEGF-A at <8 h; ICAM-1 was significantly increased at <8 h, while S100B and E-selectin were unchanged.

Conclusions: Plasma NF-L levels, but not IL-6 and S100B, were significant predictors of clinical severity on admission and functional outcome at 3 months. Plasma NF-L is a promising biomarker of functional outcome after ischemic stroke.

Optical coherence tomography-based assessment of retinal vascular pathology in cerebral small vessel disease

Background

Cerebral small vessel disease (CSVD) is a disorder of brain vasculature that causes various structural changes in the brain parenchyma, and is associated with various clinical symptoms such as cognitive impairment and gait disorders. Structural changes of brain arterioles cannot be visualized with routine imaging techniques in vivo. However, optical coherence tomography (OCT) is thought to be a “window to the brain”. Thus, retinal vessel parameters may correlate with CSVD characteristic brain lesions and cerebrospinal fluid biomarkers (CSF) of the neuropathological processes in CSVD like endothelial damage, microglial activation and neuroaxonal damage.

Methods

We applied OCT-based assessment of retinal vessels, magnetic resonance imaging (MRI), and CSF biomarker analysis in a monocentric prospective cohort of 24 patients with sporadic CSVD related stroke and cognitive impairment. MRI lesions were defined according to the STandards for ReportIng Vascular changes on nEuroimaging (STRIVE). Biomarkers were assessed using commercially available ELISA kits. Owing to the unavailability of an age-matched control-group lacking MRI-characteristics of CSVD, we compared the retinal vessel parameters in CSVD patients (73.8 ± 8.5 years) with a younger group of healthy controls (51.0 ± 16.0 years) by using an age- and sex-adjusted multiple linear regression analysis model.

Results

Among the parameters measured with OCT, the Wall to Lumen Ratio (WLR) but not Mean Wall Thickness (MWT) of the superior branch of the retinal artery correlated significantly with the volume of white matter hyperintensities on MRI (r_s = − 0.5) and with CSF-levels of Chitinase 3 like 1 protein (r_s = − 0.6), zona occludens 1 protein (r_s = − 0.5) and GFAP (r_s = − 0.4). MWT and WLR were higher in CSVD than in controls (28.9 μm vs. 23.9 μm, p = 0.001 and 0.32 vs. 0.25, p = 0.001).

Conclusions

In this exploratory study, WLR correlated with the volume of white matter hyperintensities, and markers of vascular integrity, microglial activation, and neuroaxonal damage in CSVD. Further prospective studies should clarify whether retinal vessel parameters and CSF biomarkers may serve to monitor the natural course and treatment effects in clinical studies on CSVD.

Neurofilaments in disease: what do we know?

Neurofilaments are proteins selectively expressed in the cytoskeleton of neurons, and increased levels are a marker of damage. Elevated neurofilament levels can serve as a marker of ongoing disease activity as well as a tool to measure response to therapeutic intervention. The potential utility of neurofilaments has drastically increased as recent advances have made it possible to measure levels in both the cerebrospinal fluid and blood. There is mounting evidence that neurofilament light chain (NfL) and phosphorylated neurofilament heavy chain (NfH) are abnormal in a host of neurodegenerative diseases. In this review we examine how both of these proteins behave across diseases and what we know about how these biomarkers relate to in vivo white matter pathology and each other.

Neuroprotective effects of saffron on the late cerebral ischemia injury through inhibiting astrogliosis and glial scar formation in rats

This study is to explore the neuroprotective effects and involved glial scar of saffron (Crocus sativus L.) on the late cerebral ischemia in rats. Focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in Sprague Dawley rats that were randomly divided into sham group, MCAO group, edaravone group (as a positive control) and saffron groups (saffron extract 30, 100, 300 mg/kg). Saffron was administered orally at 2 h at the first day and once daily from day 2 to 42 after ischemia. Behavioral changes were detected from day 43 to 46 after ischemia to evaluate the effects of saffron. Infarct volume, survival neuron density, activated astrocyte, and the thickness of glial scar were also detected. GFAP, neurocan, phosphocan, neurofilament expressions and inflammatory cytokine contents were detected by Western-blotting and ELISA methods, respectively. Saffron improved the body weight loss, neurological deficit and spontaneous activity. It also ameliorated anxiety-like state and cognitive dysfunction, which were detected by elevated plus maze (EPM), marble burying test (MBT) and novel object recognition test (NORT). Toluidine blue staining found that saffron treatment decreased the infarct volume and increased the neuron density in cortex in the ischemic boundary zone. The activated astrocyte number and the thickness of glial scar in the penumbra zone reduced after saffron treatment. Additionally, saffron decreased the contents of IL-6 and IL-1β, increased the content of IL-10 in the ischemic boundary zone. GFAP, neurocan, and phosphocan expressions in ischemic boundary zone and ischemic core zone all decreased after saffron treatment. Saffron exerted neuroprotective effects on late cerebral ischemia, associating with attenuating astrogliosis and glial scar formation after ischemic injury.

Neurofilaments: The C-Reactive Protein of Neurology

Neurofilaments (NFs) are quickly becoming the biomarkers of choice in the field of neurology, suggesting their use as an unspecific screening marker, much like the use of elevated plasma C-reactive protein (CRP) in other fields. With sensitive techniques being readily available, evidence is growing regarding the diagnostic and prognostic value of NFs in many neurological disorders. Here, we review the latest literature on the structure and function of NFs and report the strengths and pitfalls of NFs as markers of neurodegeneration in the context of neurological diseases of the central and peripheral nervous systems.

Serum Neurofilament Light Predicts Severity and Prognosis in Patients with Ischemic Stroke

Serum neurofilaments are markers of axonal injury. We investigated whether serum neurofilament light (sNfL) is a potential prognostic marker of functional outcome in Chinese patients with acute ischemic stroke (AIS). From May 2015 to December 2018, consecutive patients with AIS from the Department of Neurology of the Second Hospital of Jilin University were included. sNfL concentration was tested at baseline, and stroke severity was analyzed at admission using the NIHSS score. Functional outcome was assessed at discharge by the modified Rankin scale (mRS). The sNfL concentration was tested in 343 patients with a median value of 17.8 (IQR, 13.4-25.2) pg/ml. sNfL concentration paralleled lesion size (P = 0.035). At admission, 174 patients were defined as moderate-to-high stroke (NIHSS ≥ 5); the sNfL concentration in those patients were higher than that observed in patients with minor clinical severity [21.2 (IQR, 15.1-31.7) vs. 14.9 (11.8-19.4) pg/ml, P < 0.001]. For each 1 quartile increase of sNfL concentration, the unadjusted and adjusted risk of moderate-to-high stroke increased by 202% (with the OR of 3.04 (95% CI 2.15-4.32), P < 0.001) and 102% [2.02 (1.10-3.16), P = 0.001), respectively. At discharge, 85 patients (24.8%) had poor functional outcome (mRS, 3-6); the sNfL concentration in those patients were higher than that observed in patients with good outcome [24.1 (IQR, 18.8-33.9) vs. 15.7 (11.9-21.8) pg/ml, P < 0.001]. For each 1 quartile increase of sNfL concentration, the unadjusted and adjusted risk of poor outcome increased by 236% [with the OR of 3.36 (95% CI 2.23-5.06), P < 0.001] and 102% [2.29 (1.37-3.82), P < 0.001], respectively. The results show sNfL is meaningful blood biomarker to monitor stroke severity and functional outcome in ischemic stroke, suggesting that sNfL may play a role in stroke progression.

The Association Between Phosphorylated Neurofilament Heavy Chain (pNF-H) and Small Fiber Neuropathy (SFN) in Patients with Impaired Glucose Tolerance

INTRODUCTION

Small fiber neuropathy (SFN)-the early stage of diabetic peripheral neuropathy (DPN)-progresses gradually and is difficult to diagnose using neurophysiological tests. To facilitate the early diagnosis of SFN, biomarkers for SFN must be identified. The purpose of this study was to investigate the characteristics of SFN in prediabetic patients and the relationship between pNF-H and SFN.

METHODS

44 IGT patients (inpatients and outpatients) were selected at random. 33 healthy subjects served as controls. Data on clinical characteristics and laboratory parameters were collected. Quantitative sensory testing (QST), electromyography (EMG), and Sudoscan were performed, and pNF-H was measured by ELISA.

RESULTS

24 of the 44 patients with impaired glucose tolerance (IGT) were diagnosed with SFN according to the modified Toronto Diabetic Neuropathy Expert Group consensus criteria. The thermal sensory thresholds of the IGT-SFN group were significantly different from those of the CTRL group (p < 0.05), except for the heat pain threshold. The sensory nerve action potential (SNAP) of the sural nerve was 12.39 in the IGT-SFN group, which was significantly lower than those in the other groups. No significant difference in nerve conduction velocity (NCV) was observed among the three groups. The electrochemical skin conductance (ESC) in the IGT-SFN group was 69.78 ± 14.03uS, which was significantly lower than that in the CTRL group. The pNF-H in the IGT-SFN group was 170.6 (140.0, 223.6) pg/ml, which was significantly higher than those in the CTRL and IGT-non-SFN groups (76.55 and 64.7 pg/ml, respectively). Multivariate regression analysis demonstrated that pNF-H and 2h plasma glucose were independently correlated with SFN; the ORs (95% CI) were 1.429 (1.315, 1.924) and 2.375 (1.157, 4.837), respectively.

CONCLUSIONS

Serum pNF-H may be associated with SFN in IGT patients, and serum pNF-H could therefore serve as a sensitive biomarker for the detection of SFN.

Circulating neurofilament light in ischemic stroke: temporal profile and outcome prediction

Background and purpose

Neurofilament light chain (NfL) is a marker of neuroaxonal damage. We aimed to study associations between serum NfL (sNfL) concentrations at different time points after ischemic stroke and outcomes.

Methods

We prospectively included ischemic stroke cases (n = 595, mean age 59 years, 64% males) and assessed outcomes by both the modified Rankin Scale (mRS) and the NIH stroke scale (NIHSS) at 3 months and by mRS at 2 years. In a subsample, long-term (7-year) outcomes were also assessed by both mRS and NIHSS. We used the ultrasensitive single-molecule array assay to measure sNfL in the acute phase (range 1–14, median 4 days), after 3 months and 7 years in cases and once in controls (n = 595).

Results

Acute-phase sNfL increased by the time to blood-draw and highest concentrations were observed at 3 months post-stroke. High sNfL associated to stroke severity and poor outcomes, and both associations were strongest for 3-month sNfL. After adjusting for age, previous stroke, stroke severity, and day of blood draw, 3-month sNfL was significantly associated to both outcomes at all time points (p < 0.01 throughout). For all main etiological subtypes, both acute phase and 3-month sNfL were significantly higher than in controls, but the dynamics of sNfL differed by stroke subtype.

Conclusions

The results from this study inform on sNfL in ischemic stroke and subtypes over time, and show that sNfL predicts short- and long-term neurological and functional outcomes. Our findings suggest a potential utility of sNfL in ischemic stroke outcome prediction.

Electronic supplementary material

The online version of this article (10.1007/s00415-019-09477-9) contains supplementary material, which is available to authorized users.

Cerebrospinal fluid light and heavy neurofilament level increased in anti-N-methyl-d-aspartate receptor encephalitis

BACKGROUND

Neurofilaments (Nf) are a series of highly specific scaffolding proteins of neurons. Neurofilament light chains (Nf-L) and the heavy one (Nf-H) are subunits of Nf, and they are recognized as potent productions of neural damage. The concentrations of Nf aggrandized significantly in neurological disease including neuromyelitis optica, multiple sclerosis, and Alzheimer's disease. However, whether Nf in cerebrospinal fluid (CSF) elevated in anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is unclear. Here, we aimed to detect whether CSF Nf is altered in NMDAR and whether changes in CSF Nf can serve as an objective and effective biomarker to evaluate disease severity and prognosis.

METHODS

We collected 24 anti-NMDAR encephalitis patients, 11 viral meningoencephalitis/encephalitis (VM) patients, and 21 controls in this study. CSF Nf-L, Nf-H, and cytokine levels (IL-1β, IL-6, and IL-17A) were determined by enzyme-linked immunosorbent assay (ELISA) and compared between groups. We evaluated patients' clinical outcomes or prognosis according to modified Rankin scale (mRS) score.

RESULTS

Compared with controls, both CSF Nf-L and Nf-H levels were significantly increased in anti-NMDAR encephalitis patients. While compared with VM patients, only Nf-L were increased in anti-NMDAR encephalitis patients. Moreover, CSF Nf-L were positively correlated with concentration of cytokines (IL-1β, IL-17A) and mRS scores in anti-NMDAR encephalitis patients. After treatment, both CSF Nf-L and Nf-H levels decreased. Furthermore, the Nf-L during follow-up positively correlated with 3-month mRS scores, and ΔNf-L positively correlated with ΔmRS.

CONCLUSIONS

Briefly, CSF Nf-L levels notably increased in anti-NMDAR encephalitis patients in acute phase and positively correlated with disease severity. It could be considered as a useful indicator for clinical outcomes and prognosis.

Serum Neurofilament Light Chain Concentration Correlates with Infarct Volume but Not Prognosis in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

We studied serum neurofilaments diagnostic value in patients with acute ischemic stroke (AIS) or TIA and evaluated any correlation with symptom severity, cerebral infarction volume, aetiology, and clinical outcome.

METHODS

One hundred and thirty-six patients (101 with AIS, and 35 with TIA) were included. Acute-phase serum neurofilament light chain (sNfL) was analyzed with a novel ultrasensitive single molecule array (Simoa). Cerebral infarction volume was measured from brain computed tomography in the subacute phase (>2 days). Stroke aetiology was defined by trial of ORG 10172 in acute stroke treatment classification, severity by National Institute of Health stroke scale (NIHSS) and the degree of disability by the Modified Rankin Scale (mRS) after 90 days.

RESULTS

sNfL was markedly higher in patients with AIS (89.5 pg/mL [IQR: 44.7-195.3]) than with TIA (25.2 pg/mL [IQR: 14.6-48.0]), P= <.001), also after adjusting for age, NIHSS, and stroke volume (P= .003). In receiver operating characteristic analysis, sNfL concentration greater than or equal to 49 pg/mL proved to be the best cut-off value to differentiate between patients with stroke and those with TIA (sensitivity of 73% and specificity of 80%). sNfL concentration significantly correlated with cerebral infarction volume (r = .413, P= <.001), this association remained significant after adjusting for established predictors (P= .019). Patients with AIS due to cardioembolism or large artery atherosclerosis had the highest sNfL concentrations. NIHSS on admission (r = .343, P = <.001) and mRS scores after 3 months (r = .306, P = .004) correlated with sNfL concentration, however functional outcome 3 months after stroke was not associated with sNfL after adjusting for potential confounders.

CONCLUSIONS

Cases with stroke were distinguishable from those with TIA following the determination of sNfL in the blood samples. The presence and amount of axonal damage estimated by sNfL correlated with the final cerebral infarction volume but was not predictive of degree of disability.

Does cognitive dysfunction correlate with neurofilament light polypeptide levels in the CSF of patients with multiple sclerosis?

Objective

To investigate whether neurofilament light polypeptide (NfL) level in cerebrospinal fluid (CSF), currently a prognostic biomarker of neurodegeneration in patients with multiple sclerosis (MS), may be a potential biomarker of cognitive dysfunction in MS.

Methods

This observational case–control study included patients with MS. CSF levels of NfL were determined using enzyme-linked immunosorbent assay. Cognitive function was measured with the Brief International Cognitive Assessment for MS (BICAMS) battery and Paced Auditory Serial Addition Test (PASAT3), standardized to the Greek population.

Results

Of 39 patients enrolled (aged 42.7 ± 13.6 years), 36% were classified as cognitively impaired according to BICAMS z-scores (–0.34 ± 1.13). Relapsing MS was significantly better than progressive forms regarding BICAMS z-score (mean difference [MD] 1.39; 95% confidence interval [CI] 0.54, 2.24), Symbol Digit Modality Test score (MD 1.73; 95% CI 0.46, 3.0) and Greek Verbal Learning Test (MD 1.77; 95% CI 0.82, 2.72). An inversely proportional association between CSF NfL levels and BICAMS z-scores was found in progressive forms of MS (r_p = –0.944).

Conclusions

This study provides preliminary evidence for an association between CSF NfL levels and cognition in progressive forms of MS, which requires validation in larger samples.

Three-vessel coronary artery disease may predict changes in biochemical brain injury markers after off-pump coronary artery bypass grafting. J Zhejiang Univ Sci B 2019;19:735-738. [PMID: 30178640 PMCID: PMC6137419 DOI: 10.1631/jzus.b1700553]

Neurological injury is a frequent and important complication of coronary artery bypass grafting (CABG). Several risk factors for this type of sequela have been identified, among them aortic arch atherosclerosis. Our previous study indicated that atherosclerotic burden in coronary arteries may likewise predict postoperative neurological complications (Pawliszak et al., 2016b). We assessed the severity of this condition by using the SYNTAX score calculator. However, diagnosing angiographic three-vessel coronary artery disease (3VD) could be an even simpler method of achieving this goal.

Serum neurofilament light: A biomarker of neuroaxonal injury after ischemic stroke

OBJECTIVE

To explore the utility of serum neurofilament light chain (NfL) as a biomarker for primary and secondary neuroaxonal injury after ischemic stroke (IS) and study its value for the prediction of clinical outcome.

METHODS

We used an ultrasensitive single-molecule array assay to measure serum NfL levels in healthy controls (n = 30) and 2 independent cohorts of patients with IS: (1) with serial serum sampling at hospital arrival (n = 196), at days 2, 3, and 7 (n = 89), and up to 6 months post stroke; and (2) with standardized MRI at baseline and at 6 months post stroke, and with cross-sectional serum sampling at 6 months (n = 95). We determined the temporal profile of serum NfL levels, their association with imaging markers of neuroaxonal injury, and with clinical outcome.

RESULTS

Patients with IS had higher serum NfL levels compared with healthy controls starting from admission until 6 months post stroke. Serum NfL levels peaked at day 7 (211.2 pg/mL [104.7-442.6], median [IQR]) and correlated with infarct volumes (day 7: partial r = 0.736, p = 1.5 × 10^-15). Six months post stroke, patients with recurrent ischemic lesions on MRI (n = 19) had higher serum NfL levels compared to those without new lesions (n = 76, p = 0.002). Serum NfL levels 6 months post stroke further correlated with a quantitative measure of secondary neurodegeneration obtained from diffusion tensor imaging MRI (r = 0.361, p = 0.001). Serum NfL levels 7 days post stroke independently predicted modified Rankin Scale scores 3 months post stroke (cumulative odds ratio [95% confidence interval] = 2.35 [1.60-3.45]; p = 1.24 × 10^-05).

CONCLUSION

Serum NfL holds promise as a biomarker for monitoring primary and secondary neuroaxonal injury after IS and for predicting functional outcome.

Impaired Neurofilament Integrity and Neuronal Morphology in Different Models of Focal Cerebral Ischemia and Human Stroke Tissue

As part of the neuronal cytoskeleton, neurofilaments are involved in maintaining cellular integrity. In the setting of ischemic stroke, the affection of the neurofilament network is considered to mediate the transition towards long-lasting tissue damage. Although peripheral levels of distinct neurofilament subunits are shown to correlate with the clinically observed severity of cerebral ischemia, neurofilaments have so far not been considered for neuroprotective approaches. Therefore, the present study systematically addresses ischemia-induced alterations of the neurofilament light (NF-L), medium (NF-M), and heavy (NF-H) subunits as well as of α-internexin (INA). For this purpose, we applied a multi-parametric approach including immunofluorescence labeling, western blotting, qRT-PCR and electron microscopy. Analyses comprised ischemia-affected tissue from three stroke models of middle cerebral artery occlusion (MCAO), including approaches of filament-based MCAO in mice, thromboembolic MCAO in rats, and electrosurgical MCAO in sheep, as well as human autoptic stroke tissue. As indicated by altered immunosignals, impairment of neurofilament subunits was consistently observed throughout the applied stroke models and in human tissue. Thereby, altered NF-L immunoreactivity was also found to reach penumbral areas, while protein analysis revealed consistent reductions for NF-L and INA in the ischemia-affected neocortex in mice. At the mRNA level, the ischemic neocortex and striatum exhibited reduced expressions of NF-L- and NF-H-associated genes, whereas an upregulation for Ina appeared in the striatum. Further, multiple fluorescence labeling of neurofilament proteins revealed spheroid and bead-like structural alterations in human and rodent tissue, correlating with a cellular edema and lost cytoskeletal order at the ultrastructural level. Thus, the consistent ischemia-induced affection of neurofilament subunits in animals and human tissue, as well as the involvement of potentially salvageable tissue qualify neurofilaments as promising targets for neuroprotective strategies. During ischemia formation, such approaches may focus on the maintenance of neurofilament integrity, and appear applicable as co-treatment to modern recanalizing strategies.

Neurofilament as Neuronal Injury Blood Marker in Preeclampsia

Preeclampsia has been shown to be associated with changes in cerebral structure and cognitive function later in life. Nf (neurofilaments) are specific scaffolding proteins of neurons, and their quantification in serum has been proposed as a biomarker for neuroaxonal injury. We performed a prospective, longitudinal, single-center study at the University Hospital of Basel to determine serum Nf concentrations in pregnant women with singleton pregnancies and with high risk of preeclampsia or with early signs of preeclampsia. Enrollment started at 21 weeks of gestation, followed up with multiple visits until delivery. Sixty out of 197 women developed preeclampsia (30.5%). NfL (Nf light chain) was measured with a highly sensitive single molecule array (Simoa) assay, in addition to the established preeclampsia markers sFlt-1 (soluble fms-like tyrosine kinase-1) and PlGF (placental growth factor). The most important independent predictors of NfL were maternal age, number of pregnancies, and proteinuria. NfL levels increased during pregnancy and were significantly higher in women developing preeclampsia. The discriminatory accuracy of NfL, PlGF, and sFlt-1 in receiver operating characteristic curves analysis (area under the curve) of the overall group was 0.68, 0.81, and 0.84, respectively, and in women older than 36 years 0.7, 0.62, and 0.79, respectively. We conclude that increased axonal injury serum marker NfL predicts preeclampsia particularly in older women, with an accuracy similar to the established angiogenic factors. NfL may serve as an early indicator of preeclampsia-induced changes in cerebral structure and may help to stratify disease management.

Patients with chronic insomnia disorder have increased serum levels of neurofilaments, neuron-specific enolase and S100B: does organic brain damage exist?

OBJECTIVES

The aims of this study were to investigate whether serum levels of neurofilaments heavy chain (NfH) and light chain (NfL), neuron-specific enolase (NSE) and S100 calcium binding protein B (S100B): (1) change, (2) alleviate in post-therapy and (3) are associated with sleep quality and cognitive dysfunction, in patients with chronic insomnia disorder (CID).

METHODS

Forty CID outpatients constituted free-therapy group (ft-CID), in which twenty-four patients completed follow-up after six-month treatment to form re-visiting group (rv-CID), and twenty healthy good sleepers constituted control group (HC). All subjects completed questionnaires, polysomnography, Chinese-Beijing Version of Montreal Cognitive Assessment (MoCA-C) and Nine Box Maze Test (NBMT) to assess sleep and neuropsychological function. The serum levels of NfH, NfL, NSE and S100B were detected using enzyme-linked immunosorbent assay.

RESULTS

The ft-CID had higher levels of NfH, NfL, NSE and S100B than the HC. Of note, the levels of NfH, NfL and NSE were significantly reduced in the rv-CID compared to the ft-CID, but not the level of S100B. Principal components analysis revealed that in these serum biomarkers, NfL and S100B had a substantial correlation with subjective and objective sleep parameters.

CONCLUSIONS

The CID patients had elevated serum levels of NfH, NfL, NSE and S100B, indicating existence of damaged brain microstructure, including neurons, astrocytes and neuronal terminals, which were associated with the insomniac severity or/and cognitive dysfunction and could significantly reduce after effective therapy apart from the S100B.

Plasma phosphorylated neurofilament heavy chains as a potential marker for ischemic stroke patients

Background: The aim of the study was to determine the utility of plasma NfH in correlation with serum hsCRP for severity and short-term functional outcome prediction after ischemic stroke. Methods: 124 patients and 40 healthy controls were enrolled, serial plasma neurofilament heavy chains and hsCRP concentrations were measured and evaluated for TOAST subtype, stroke severity and functional outcome at discharge. Results: Serum level of hsCRP was significantly higher in patients versus controls (p<0.05) with no difference between TOAST subtypes. Plasma NfH concentration on day 5 was higher in CE stroke compared to LAA group and SVO group. A positive correlation between NfH levels on day 5 and mRS at discharge (r=0.304, p=0.001) and a gender stratification of hsCRP and mRS at discharge was found. Values of 6.04 mg/l for hsCRP and 46.4 ng/ml for NfH were found predictive for unfavorable short-term outcome, but after adjusting for age, sex and stroke severity, the prediction power was lost. Conclusions: Plasma concentration of NfH shows a significant increase over the first five days after ischemic stroke, in correlation with inflammatory status and short-term evolution.

Serum neurofilament light chain in patients with acute cerebrovascular events

BACKGROUND AND PURPOSE

Serum neurofilaments are markers of axonal injury. We addressed their diagnostic and prognostic role in acute ischemic stroke (AIS) and transient ischemic attack (TIA).

METHODS

Nested within a prospective cohort study, we compared levels of serum neurofilament light chain (sNfL) drawn within 24 h from symptom onset in patients with AIS or TIA. Patients without magnetic resonance imaging on admission were excluded. We assessed whether sNfL was associated with: (i) clinical severity on admission, (ii) diagnosis of AIS vs. TIA, (iii) infarct size on admission magnetic resonance diffusion-weighted imaging (MR-DWI) and (iv) functional outcome at 3 months.

RESULTS

We analyzed 504 patients with AIS and 111 patients with TIA. On admission, higher National Institutes of Health Stroke Scale (NIHSS) scores were associated with higher sNfL: NIHSS score < 7, 13.1 pg/mL [interquartile range (IQR), 5.3-27.8]; NIHSS score 7-15, 16.7 pg/mL (IQR, 7.4-34.9); and NIHSS score > 15, 21.0 pg/mL (IQR, 9.3-40.4) (P = 0.01). Compared with AIS, patients with TIA had lower sNfL levels [9.0 pg/mL (95% confidence interval, 4.0-19.0) vs. 16.0 pg/mL (95% confidence interval, 7.3-34.4), P < 0.001], also after adjusting for age and NIHSS score (P = 0.006). Among patients with AIS, infarct size on admission MR-DWI was not associated with sNfL, either in univariate analysis (P = 0.15) or after adjusting for age and NIHSS score on admission (P = 0.56). Functional outcome 3 months after stroke was not associated with sNfL after adjusting for established predictors.

CONCLUSIONS

In conclusion, among patients admitted within 24 h of AIS or TIA onset, admission sNfL levels were associated with clinical severity on admission and TIA diagnosis, but not with infarct size on MR-DWI acquired on admission or functional outcome at 3 months.

Neuronal Damage Induced by Perinatal Asphyxia Is Attenuated by Postinjury Glutaredoxin-2 Administration

The general disruption of redox signaling following an ischemia-reperfusion episode has been proposed as a crucial component in neuronal death and consequently brain damage. Thioredoxin (Trx) family proteins control redox reactions and ensure protein regulation via specific, oxidative posttranslational modifications as part of cellular signaling processes. Trx proteins function in the manifestation, progression, and recovery following hypoxic/ischemic damage. Here, we analyzed the neuroprotective effects of postinjury, exogenous administration of Grx2 and Trx1 in a neonatal hypoxia/ischemia model. P7 Sprague-Dawley rats were subjected to right common carotid ligation or sham surgery, followed by an exposure to nitrogen. 1 h later, animals were injected i.p. with saline solution, 10 mg/kg recombinant Grx2 or Trx1, and euthanized 72 h postinjury. Results showed that Grx2 administration, and to some extent Trx1, attenuated part of the neuronal damage associated with a perinatal hypoxic/ischemic damage, such as glutamate excitotoxicity, axonal integrity, and astrogliosis. Moreover, these treatments also prevented some of the consequences of the induced neural injury, such as the delay of neurobehavioral development. To our knowledge, this is the first study demonstrating neuroprotective effects of recombinant Trx proteins on the outcome of neonatal hypoxia/ischemia, implying clinical potential as neuroprotective agents that might counteract neonatal hypoxia/ischemia injury.

Diagnostic and Prognostic Biomarkers in Amyotrophic Lateral Sclerosis: Neurofilament Light Chain Levels in Definite Subtypes of Disease

Importance

A clearer definition of the role of neurofilament light chain (NFL) as a biomarker in amyotrophic lateral sclerosis (ALS) is needed.

Objectives

To assess the ability of NFL to serve as a diagnostic biomarker in ALS and the prognostic value of cerebrospinal fluid NFL in patients with ALS.

Design, Setting, and Participants

In this single-center, retrospective, longitudinal study, disease progression was assessed by the ALS Functional Rating Score-Revised and the ALS Milano-Torino Staging system at baseline and 6, 12, 24, and 36 months. Cerebrospinal fluid samples were obtained from 176 patients admitted to the Department of Neurosciences of the University of Padua, Padova, Italy, from January 1, 2010, through February 29, 2016. Patients with ALS underwent ambulatory follow-up at the same department.

Main Outcomes and Measures

Levels of NFL.

Results

The study included 94 patients with ALS (64 men [36.4%] and 30 women [17.0%]; median age, 62.5 years), 20 patients with frontotemporal dementia (FTD) (8 men [4.5%] and 12 women [6.8%]; median age, 65 years), 18 patients with motor neuropathies (14 men [8.0%] and 4 women [2.3%]; median age, 63 years), and 44 controls (24 men [13.6%] and 20 women [11.4%]; median age, 54 years). Log-transformed NFL (log[NFL]) concentrations were higher in the ALS and FTD groups compared with the motor neuropathies and control groups (hazard ratio [HR], 2.45; 95% CI, 1.66-3.61; P < .001). Patients with typical ALS (HR, 1.0 [reference]), progressive bulbar palsy (HR, 1.48; 95% CI, 0.58-3.75; P = .41), and upper motor neuron dominant ALS (HR, 0.12; 95% CI, 0.02-0.61; P = .01) had higher levels of NFL than did those with flail arm or leg syndrome (HR, 0.28; 95% CI, 0.08-0.10; P = .049) and progressive muscular atrophy (HR, 0.17; 95% CI, 0.22-1.36; P = .10). There was an inverse correlation between log[NFL] concentration and overall survival (HR, 2.45; 95% CI, 1.66-3.61; P < .001). There was no evidence of different log[NFL] concentrations and survival in genetic ALS.

Conclusions and Relevance

This study confirms the role of NFL as a biomarker in ALS. Elevation in NFL levels in patients with upper motor neuron involvement and FTD might reflect the corticospinal tract degeneration. Low NFL levels in patients with lower motor neuron signs might be a prognostic indicator of milder phenotypes of disease.

Biomarkers Associated with Cognitive Impairment in Treated Cancer Patients: Potential Predisposition and Risk Factors

Purpose: Cognitive impairment in cancer patients induced, at least in part, by treatment are frequently observed and likely have negative impacts on patient quality of life. Such cognitive dysfunctions can affect attention, executive functions, and memory and processing speed, can persist after treatment, and their exact causes remain unclear. The aim of this review was to create an inventory and analysis of clinical studies evaluating biological markers and risk factors for cognitive decline in cancer patients before, during, or after therapy. The ultimate objectives were to identify robust markers and to determine what further research is required to develop original biological markers to enable prevention or adapted treatment management of patients at risk.

Method: This review was guided by the PRISMA statement and included a search strategy focused on three components: “cognition disorders,” “predictive factors”/“biological markers,” and “neoplasms,” searched in PubMed since 2005, with exclusion criteria concerning brain tumors, brain therapy, and imaging or animal studies.

Results: Twenty-three studies meeting the criteria were analyzed. Potential associations/correlations were identified between cognitive impairments and specific circulating factors, cerebral spinal fluid constituents, and genetic polymorphisms at baseline, during, and at the end of treatment in cancer populations. The most significant results were associations between cognitive dysfunctions and genetic polymorphisms, including APOE-4 and COMT-Val; increased plasma levels of the pro-inflammatory cytokine, IL-6; anemia; and hemoglobin levels during chemotherapy. Plasma levels of specific hormones of the hypothalamo-pituitary-adrenal axis are also modified by treatment.

Discussion: It is recognized in the field of cancer cognition that cancer and comorbidities, as well as chemotherapy and hormone therapy, can cause persistent cognitive dysfunction. A number of biological circulating factors and genetic polymorphisms, can predispose to the development of cognitive disorders. However, many predictive factors remain unproven and discordant findings are frequently reported, warranting additional clinical and preclinical longitudinal cohort studies, with goals of better characterization of potential biomarkers and identification of patient populations at risk and/or particularly deleterious treatments. Research should focus on prevention and personalized cancer management, to improve the daily lives, autonomy, and return to work of patients.

Effect of carotid endarterectomy on brain damage markers

OBJECTIVES

Carotid endarterectomy (CEA) is a recommended treatment in the prevention of ischemic stroke. However, this procedure may cause neurological complications caused by cerebrovascular damage. While YKL-40 is a proinflammatory protein, neurofilament light polypeptide (NEFL) and brain lipid-binding protein (FABP7) are structural components of the brain. The aim of the study was to investigate YKL-40, NEFL, and FABP7 in the serum of patients undergoing CEA.

MATERIALS AND METHODS

The study included 25 participants who underwent CEA due to internal carotid artery stenosis. Blood samples were taken from each patient at three different intervals: prior to the surgery, 12 h after the surgery, and 48 h after the surgery. Serum levels of these brain damage markers were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The study showed that the serum YKL-40 level was significantly increased 48 h after CEA when compared to the level prior to surgery and also when compared to levels 12 h after surgery. There were no statistically significant differences in serum NEFL and FABP7 levels between all three recorded measurements.

CONCLUSIONS

Data from our study showed that CEA affects serum YKL-40 but not NEFL and FABP7 levels. This implicates that YKL-40 may be a valuable serum marker of brain damage after CEA. However, the observed change in serum YKL-40 level in patients after CEA does not necessarily warrant a change in recommendations concerning the use of this treatment in patients with high-grade internal carotid artery stenosis.

Exosomes Derived from Mesenchymal Stromal Cells Promote Axonal Growth of Cortical Neurons

Treatment of brain injury with exosomes derived from mesenchymal stromal cells (MSCs) enhances neurite growth. However, the direct effect of exosomes on axonal growth and molecular mechanisms underlying exosome-enhanced neurite growth are not known. Using primary cortical neurons cultured in a microfluidic device, we found that MSC-exosomes promoted axonal growth, whereas attenuation of argonaut 2 protein, one of the primary microRNA (miRNA) machinery proteins, in MSC-exosomes abolished their effect on axonal growth. Both neuronal cell bodies and axons internalized MSC-exosomes, which was blocked by botulinum neurotoxins (BoNTs) that cleave proteins of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. Moreover, tailored MSC-exosomes carrying elevated miR-17-92 cluster further enhanced axonal growth compared to native MSC-exosomes. Quantitative RT-PCR and Western blot analysis showed that the tailored MSC-exosomes increased levels of individual members of this cluster and activated the PTEN/mTOR signaling pathway in recipient neurons, respectively. Together, our data demonstrate that native MSC-exosomes promote axonal growth while the tailored MSC-exosomes can further boost this effect and that tailored exosomes can deliver their selective cargo miRNAs into and activate their target signals in recipient neurons. Neuronal internalization of MSC-exosomes is mediated by the SNARE complex. This study reveals molecular mechanisms that contribute to MSC-exosome-promoted axonal growth, which provides a potential therapeutic strategy to enhance axonal growth.

Serum Phosphorylated Neurofilament-Heavy Chain, a Potential Biomarker, is Associated With Peripheral Neuropathy in Patients With Type 2 Diabetes

Neurofilament (NF), one of the major axonal cytoskeletal proteins, plays a critical role in degenerative diseases in both the central and the peripheral nervous systems. The aim of this study is to explore the relationship between serum phosphorylated neurofilament-heavy chain (pNF-H) and diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes.Serum pNF-H concentrations were measured by ELISA in hospitalized patients with and without DPN (n = 118). DPN was assessed by clinical symptoms, signs, and electromyography.Compared with the non-DPN group (311.98 [189.59-634.12] pg/mL), the confirmed group (605.99 [281.17-1332.78] pg/mL) patients had the higher serum pNF-H levels (P = 0.007). DPN was significantly correlated with C-peptide (r = -0.269), total cholesterol (TC) (r = 0.185), and pNF-H (r = 0.258). Serum pNF-H levels were independently associated with DPN (P = 0.004), even after adjusting for age, sex, duration of diabetes, fasting plasma glucose, glycosylated hemoglobin A1c, TC, C-peptide, urinary albuminto/creatinine ratio, and estimated glomerular filtration rate. Compared with pNF-H quartile 1 (referent), patients in quartile 3 (odds ratio [OR], 3.977; 95% confidence interval [CI], 1.243-12.728; P = 0.021) and quartile 4 (OR, 10.488; 95% CI, 3.020-34.429; P = 0.000) had the higher risk of DPN after adjusting for the confounders.Serum pNF-H levels might be associated with the DPN, and the correlationship between serum pNF-H and DPN should be further studied.

The back and forth of axonal injury and repair after stroke

PURPOSE OF REVIEW

The axon plays a central role in both the injury and repair phases after stroke. This review highlights emerging principles in the study of axonal injury in stroke and the role of the axon in neural repair after stroke.

RECENT FINDINGS

Ischemic stroke produces a rapid and significant loss of axons in the acute phase. This early loss of axons results from a primary ischemic injury that triggers a wave of calcium signaling, activating proteolytic mechanisms and downstream signaling cascades. A second progressive phase of axonal injury occurs during the subacute period and damages axons that survive the initial ischemic insult but go on to experience a delayed axonal degeneration driven in part by changes in axoglial contact and axonal energy metabolism. Recovery from stroke is dependent on axonal sprouting and reconnection that occurs during a third degenerative/regenerative phase. Despite this central role played by the axon, comparatively little is understood about the molecular pathways that contribute to early and subacute axonal degeneration after stroke. Recent advances in axonal neurobiology and signaling suggest new targets that hold promise as potential molecular therapeutics including axonal calcium signaling, axoglial energy metabolism and cell adhesion as well as retrograde axonal mitogen-activated protein kinase pathways. These novel pathways must be modeled appropriately as the type and severity of axonal injury vary by stroke subtype.

SUMMARY

Stroke-induced injury to axons occurs in three distinct phases each with a unique molecular underpinning. A wealth of new data about the molecular organization and molecular signaling within axons is available but not yet robustly applied to the study of axonal injury after stroke. Identifying the spatiotemporal patterning of molecular pathways within the axon that contribute to injury and repair may offer new therapeutic strategies for the treatment of stroke.

Serial measurements of phosphorylated neurofilament-heavy in the serum of subjects with amyotrophic lateral sclerosis

There is a need for a blood biomarker of disease activity in ALS. This marker needs to measure the loss of motor neurones. Phosphorylated neurofilament heavy chain (pNfH) in the serum is a biomarker of axonal injury. Previous studies have found that levels of pNfH are elevated in ALS. We have performed a serial study of pNfH levels in 98 subjects from our ALS clinic. There was significant elevation of levels of pNfH in subjects with ALS compared to controls, although there was considerable variability. In studies of individuals who had two or more serial samples, we found that the levels of pNfH increased over time in the early stage of disease. Levels were low in subjects with long survival. The rate of rise of pNfH was inversely correlated with survival. We suggest that the initial level of pNfH is a marker of disease severity and that changes in pNfH levels are markers of disease progression.

Combination of serum phosphorylated neurofilament heavy subunit and hyperintensity of intramedullary T2W on magnetic resonance imaging provides better prognostic value of canine thoracolumbar intervertebral disc herniation

The aim of this study was to evaluate the prognostic value of concurrent measurement of serum phosphorylated neurofilament heavy subunit (pNF-H) concentration and intramedullary T2W hyperintensity in paraplegic to paraplegic dogs. Our hypothesis was that concurrent measurement of these would provide a more accurate prediction of functional outcome in dogs with thoracolumbar intervertebral disc herniation (IVDH). A prospective case-control clinical study was designed using 94 dogs with acute onset of thoracolumbar IVDH. The association of serum pNF-H concentration, T2W hyperintensity on sagittal MRI (T2H/L2), deep pain perception and surgical outcome were evaluated with logistic regression analysis after three months for all 94 surgically treated dogs. Sensitivity to predict non-ambulatory outcome was compared among pNF-H and T2H/L2 and combination of both. Logistic regression analysis indicated that serum pNF-H concentration and T2H/L2 were significantly correlated with surgical outcome (P<0.05); however, deep pain perception was not (P=0.41). The results of logistic regression analysis indicated that the odds ratios of unsuccessful long-term outcome were 2.6 for serum pNF-H concentration, 1.9 for T2H/L2 and 2.3 for deep pain sensation. The sensitivity and specificity to predict non-ambulatory outcome for using serum parameter pNF-H>2.6 ng/ml, using T2H/L2 value of>0.84 and using both serum pNF-H and T2H/L2, were 95% and 75.7%, 65% and 86.5%, and 90.0% and 97.5%, respectively. Therefore, combined measurements of serum pNF-H and T2H/L2 might be useful for predicting long-term outcome in dogs with thoracolumbar IVDH.

Sacs knockout mice present pathophysiological defects underlying autosomal recessive spastic ataxia of Charlevoix-Saguenay

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS [MIM 270550]) is an early-onset neurodegenerative disorder caused by mutations in the SACS gene. Over 170 SACS mutations have been reported worldwide and are thought to cause loss of function of sacsin, a poorly characterized and massive 520 kDa protein. To establish an animal model and to examine the pathophysiological basis of ARSACS, we generated Sacs knockout (Sacs(-/-)) mice. Null animals displayed an abnormal gait with progressive motor, cerebellar and peripheral nerve dysfunctions highly reminiscent of ARSACS. These clinical features were accompanied by an early onset, progressive loss of cerebellar Purkinje cells followed by spinal motor neuron loss and peripheral neuropathy. Importantly, loss of sacsin function resulted in abnormal accumulation of non-phosphorylated neurofilament (NF) bundles in the somatodendritic regions of vulnerable neuronal populations, a phenotype also observed in an ARSACS brain. Moreover, motor neurons cultured from Sacs(-/-) embryos exhibited a similar NF rearrangement with significant reduction in mitochondrial motility and elongated mitochondria. The data points to alterations in the NF cytoskeleton and defects in mitochondrial dynamics as the underlying pathophysiological basis of ARSACS.

Neurofilament heavy chain as a marker of neuroaxonal pathology and prognosis in acute encephalitis

BACKGROUND AND PURPOSE

The neurological outcome of acute encephalitis can be devastating and early prognosis remains difficult. Biomarkers that quantify the extent of early brain injury are needed to improve the prognostic accuracy and aid patient management. Our objective was to assess whether cerebrospinal fluid (CSF) protein biomarkers of neuroaxonal and glial cell injury are elevated in distinct forms of acute encephalitis and predictive of poor outcome.

METHODS

This was a prospective study of patients presenting with acute encephalitis to three teaching hospitals in London, UK. Levels of neurofilament heavy chain (NfH, SMI35) and S100B were quantified in CSF using enzyme-linked immunosorbent assay. The outcome was assessed by the Glasgow Outcome Scale (GOS).

RESULTS

Fifty-six patients with acute encephalitis were recruited and classified into the following diagnostic categories: infectious (n = 20), inflammatory (n = 14) and unknown etiology (n = 22). Pathological levels of NfH and S100B were observed in 24/56 (43%) and 54/56 (96%), respectively. Patients with infectious encephalitis had significantly higher NfH levels compared with the other two groups (P < 0.05). A poor outcome (GOS < 5) was associated with significantly higher CSF NfH levels within samples taken 2 weeks after symptom onset.

CONCLUSIONS

This study suggests that longitudinal CSF NfH levels are of superior prognostic value compared with CSF S100B levels. Prolonged release of NfH, a marker of neuroaxonal damage, was associated with poor outcome. Potentially there is a window of opportunity for future neuroprotective treatment strategies in encephalitis.

CSF neurofilament light chain is elevated in OMS (decreasing with immunotherapy) and other pediatric neuroinflammatory disorders

Using a panel of seven brain cell-specific biomarkers in cerebrospinal fluid (CSF), pediatric opsoclonus-myoclonus syndrome (OMS) (n=234) was compared to pediatric non-inflammatory neurological controls (n=84) and other inflammatory neurological disorders (OIND) (n=44). Only CSF NFL was elevated in untreated OMS versus controls (+83%). It was 87% higher in OIND than in OMS. On combination treatment with front-loaded ACTH, IVIg, rituximab, median CSF NFL decreased by 60% to control levels. These biochemical data suggest neuronal/axonal injury in some children with OMS without indicators of astrogliosis, and reduction on sufficient immunotherapy.

Increased neurofilament light chain blood levels in neurodegenerative neurological diseases

Objective

Neuronal damage is the morphological substrate of persisting neurological disability. Neurofilaments (Nf) are cytoskeletal proteins of neurons and their release into cerebrospinal fluid has shown encouraging results as a biomarker for neurodegeneration. This study aimed to validate the quantification of the Nf light chain (NfL) in blood samples, as a biofluid source easily accessible for longitudinal studies.

Methods

We developed and applied a highly sensitive electrochemiluminescence (ECL) based immunoassay for quantification of NfL in blood and CSF.

Results

Patients with Alzheimer’s disease (AD) (30.8 pg/ml, n=20), Guillain-Barré-syndrome (GBS) (79.4 pg/ml, n=19) or amyotrophic lateral sclerosis (ALS) (95.4 pg/ml, n=46) had higher serum NfL values than a control group of neurological patients without evidence of structural CNS damage (control patients, CP) (4.4 pg/ml, n=68, p<0.0001 for each comparison, p=0.002 for AD patients) and healthy controls (HC) (3.3 pg/ml, n=67, p<0.0001). Similar differences were seen in corresponding CSF samples. CSF and serum levels correlated in AD (r=0.48, p=0.033), GBS (r=0.79, p<0.0001) and ALS (r=0.70, p<0.0001), but not in CP (r=0.11, p=0.3739). The sensitivity and specificity of serum NfL for separating ALS from healthy controls was 91.3% and 91.0%.

Conclusions

We developed and validated a novel ECL based sandwich immunoassay for the NfL protein in serum (NfL^Umea47:3); levels in ALS were more than 20-fold higher than in controls. Our data supports further longitudinal studies of serum NfL in neurodegenerative diseases as a potential biomarker of on-going disease progression, and as a potential surrogate to quantify effects of neuroprotective drugs in clinical trials.

Serial soluble neurofilament heavy chain in plasma as a marker of brain injury after cardiac arrest

INTRODUCTION

Induced hypothermia has been shown to improve outcome after cardiac arrest, but early prognostication is hampered by the need for sedation. Here we tested whether a biomarker for neurodegeneration, the neurofilament heavy chain (NfH), may improve diagnostic accuracy in the first days after cardiac arrest.

METHODS

This prospective study included 90 consecutive patients treated with hypothermia after cardiac arrest. Plasma levels of phosphorylated NfH (SMI35) were quantified using standard ELISA over a period of 72 h after cardiac arrest. The primary outcome was the dichotomized Cerebral Performance Categories scale (CPC). A best CPC 1-2 during 6 months follow-up was considered a good outcome, a best CPC of 3-4 a poor outcome. Receiver operator characteristics and area under the curve were calculated.

RESULTS

The median age of the patients was 65 years, and 63 (70%) were male. A cardiac aetiology was identified in 62 cases (69%). 77 patients (86%) had out-of-hospital cardiac arrest. The outcome was good in 48 and poor in 42 patients. Plasma NfH levels were significantly higher 2 and 36 hours after cardiac arrest in patients with poor outcome (median 0.28 ng/mL and 0.5 ng/mL, respectively) compared to those with good outcome (0 ng/mL, p = 0.016, p < 0.005, respectively). The respective AUC were 0.72 and 0.71.

CONCLUSIONS

Plasma NfH levels correlate to neurological prognosis following cardiac arrest. In this study, 15 patients had neurological co-morbidities and there was a considerable overlap of data. As such, neurofilament should not be used for routine neuroprognostication until more data are available.

Serum biomarkers of neurologic injury in cardiac operations

Assessment of subtle neurocognitive decline after surgical procedures has been hampered by heterogeneous testing techniques and a lack of reproducibility. This review summarizes the sensitivity and specificity of biomarkers of neurologic injury to determine whether they can be applied in the postoperative period to accurately predict neurocognitive decline. Creatine kinase-brain type, neuron-specific enolase, and S100B can be released into serum during operations by extracranial sources. Glial fibrillary acidic protein is a sensitive marker, and there are extracranial sources that are antigenically different from the brain-derived form. Serum levels of tau protein after acute neurologic injury do not reliability correlate with incidence.

Elevated levels of S100B, tau and pNFH in cerebrospinal fluid are correlated with subtypes of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an immune-mediated inflammatory disease in the peripheral nervous system. Specific biomarkers for the two most common clinical subtypes of GBS, i.e., acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN) are still missing. The distinctive pathological features of AIDP and AMAN may lead to release of such specific biomarkers including glial markers (calcium-binding astroglial protein, S100B) and axonal damage markers [axoskeletal protein, phosphorylated neurofilament heavy protein (pNFH); cytoskeletal protein, tau], etc. To explore the potentials of biochemical markers for differential diagnosis and evaluation of prognosis of clinical subtypes in GBS, we used ELISA to measure the levels of S100B, tau and pNFH in serum and cerebrospinal fluid (CSF) from the patients with AIDP, AMAN, viral encephalitis and other non-inflammatory neurological disorders (OND), respectively. The values of albumin quotient and IgG index in CSF are significantly higher in AIDP and AMAN than in OND. The levels of S100B, tau and pNFH in serum and CSF are elevated in the patients with AIDP and AMAN compared to OND. The concentrations of these proteins are all higher in CSF than in serum. Increased levels of S100B in CSF at the acute phase are positively correlated with the GBS disability scale scores (GDSs) in AIDP, whereas enhanced levels of tau and pNFH in CSF are positively correlated with the GDSs in AMAN. Increased CSF levels of S100B, tau and pNFH at the acute phase may predict a poor prognosis and evaluate the severity of AIDP or AMAN at plateau and the recovery phase. Elevated levels of pNFH in CSF may be used for differentiating between AMAN and AIDP.

Hyperacute detection of neurofilament heavy chain in serum following stroke: a transient sign

Serological biomarkers which enable quick and reliable diagnosis or measurement of the extent of irreversible brain injury early in the course of stroke are eagerly awaited. Neurofilaments (Nf) are a group of proteins integrated into the scaffolding of the neuronal and axonal cytoskeleton and an established biomarker of neuro-axonal damage. The Nf heavy chain (NfH(SMI35)) was assessed together with brain-specific astroglial proteins GFAP and S100B in hyperacute stroke (6 and 24 h from symptom onset) and daily for up to 6 days. Twenty-two patients with suspected stroke (median NIHSS 8) were recruited in a prospective observational study. Evidence for an ischaemic or haemorrhagic lesion on neuroimaging was found in 18 (ischaemia n = 16, intracerebral haemorrhage n = 2). Serum NfH(SMI35) levels became detectable within 24 h post-stroke (P < 0.0001) and elevated levels persisted over the study course. While GFAP was not detectable during the entire course, S100B levels peaked at the end of the observation period. The data indicate that significant in vivo information on the pathophysiology of stroke may be obtained by the determination of NfH(SMI35). Further studies are required to evaluate whether NfH(SMI35) in hyperacute stroke reflects the extent of focal ischaemic injury seen on neuroimaging or is a consequence of more diffuse neuro-axonal damage.