Glial fibrillary acidic protein and neurofilament in children with cerebral white matter abnormalities

Glial fibrillary acidic protein (GFAP) is the major structural protein of the intermediate filaments found in glial cells. Increased levels in the cerebrospinal fluid (CSF) have been found to indicate gliosis. Neurofilament (NFL) is a structural element of neurons, mainly found in large myelinated axons. Its presence in the CSF has been suggested to reflect destruction of axons. The aim of this study was to see if GFAP and NFL in the CSF of children with neurological disabilities and an abnormal signal on magnetic resonance imaging (MRI) of the cerebral white matter could be used to clarify the underlying neuropathology. The potential of GFAP and NFL to differentiate a progressive disease from a stationary disorder was investigated, as was the correlation with disability and clinical findings. CSF from 26 children, eleven with progressive and 15 with non-progressive disorders, was analysed. GFAP was increased in all, interpreted to reflect gliosis. NFL was elevated in seven and considered to indicate ongoing neuroaxonal damage as all but one patient were found to have a progressive disease. GFAP did not differentiate between progressive and non-progressive disorders, although low levels were found in stationary and high levels in progressive disorders. The severity of the disability correlated with the NFL levels, but not with the concentration of GFAP.     

Neurofilament light chain in blood is negatively associated with neuropsychological performance in HIV-infected adults and declines with initiation of antiretroviral therapy

HIV-associated neurocognitive disorder (HAND) persists in the combination antiretroviral therapy (cART) era and is associated with diminished quality of life. The disorder remains challenging to diagnose given the requirement for comprehensive neuropsychological testing. Blood biomarkers are needed to facilitate the diagnosis of HAND and to gauge neurological response to antiretroviral therapy. We performed a study of plasma neurofilament light chain (NFL) that included 37 HIV-infected and 54 HIV-negative adults. In the univariate mixed-effect model involving HIV-infected participants, there was a statistically significant linear relationship between composite neuropsychological score (NPT-11) and plasma NFL (slope?=???9.9, standard error?=?3.0 with 95% confidence interval ??3.2 to ??16.6 and p?=?0.008 when testing slope?=?0). Similarly, in the multivariate mixed-effect model, higher plasma NFL was significantly associated with worse NPT-11 (slope?=???11.5, standard error?=?3.3 with 95% confidence interval ??3.7 to ??19.0 and p?=?0.01 when testing slope?=?0). The association between NPT-11 and NFL appeared to be driven by the group of individuals off cART. In a subset of participants who had visits before and after 24 weeks on cART (n?=?11), plasma NFL declined over time (median?=?22.7 versus 13.4 pg/ml, p?=?0.02). In contrast, plasma NFL tended to increase over time among HIV-negative participants (median 10.3 versus 12.6 pg/ml, p?=?0.065, n?=?54). Plasma NFL therefore shows promise as a marker of neuropsychological performance during HIV. Larger studies are needed to determine if NFL could serve as a diagnostic tool for HAND during suppressive cART.     

尿液神经丝蛋白水平与脑小血管病的关系

目的 探讨尿液神经丝蛋白轻链(Neurofilament light chain,NFL)水平与脑小血管病(Small cerebral vessel disease,SVD)的关系。方法 本研究共纳入了122例SVD患者和62例健康对照者,检测尿液NFL水平并进行磁共振(MRI)检查,记录白质高信号(WMH)相对体积、大脑相对容积、微出血灶计数和平均弥散率,同时进行NIHSS量表的测定,验证NFL水平与各指标之间的相关性。结果 SVD组患者的尿液NFL水平要显著高于健康对照组(P<0.001),健康对照组人群的NFL水平集中在20 pg/mL左右,而SVD组患者集中在40～70 pg/mL左右,NFL对于区分SVD患者和健康对照者的ROC曲线下面积为0.779; 多因素线性回归分析显示平均弥散率(P=0.019)和WMH(P=0.033)与NFL水平显著相关; 多因素有序Logistics回归分析显示平均弥散率(OR=3.27,P=0.018)和尿液NFL水平(OR=1.51,P=0.024)与NIHSS显著相关。结论 尿液NFL水平在排除其他病变后可以作为核磁共振检查的替代来判定脑小血管病的发生。     

Cytoskeleton abnormalities in axonopathies of unknown aetiology: correlations with morphometry

To determine if specific axonal cytoskeleton abnormalities could be demonstrated in axonopathies without aetiology, nerve biopsies from five controls and nine cases were analyzed by morphometry and immunocytochemistry with anti-neurofilament (NF, subunits L, M, H) and anti-beta tubulin (TUB) antibodies. Morphometry revealed either large fiber atrophy (decrease in large fiber density with increased density in small fibers), degeneration of large fibers (decrease in large fiber density and in total density of fibers) or of all diameter fibers. NF immunostaining density decreased (by 21-89%) only in cases with fiber loss, in parallel to myelinated fiber density as determined by morphometry. On the contrary, the density of fibers labelled for TUB increased significantly in all except two cases by 52-102% over controls. Nevertheless, in these two cases--with a severe loss of fibers--as well as in other cases, the ratio of the density of fibers labelled for TUB and NFL (TUB/NFL) increased by 48-404%. Thus, the total density of myelinated fibers was always inversely correlated with the TUB/NFL ratio. Similar abnormalities have been described only after axotomy; our cases could thus be compared to .     

Neurofilament protein in cerebrospinal fluid: a marker of white matter changes.

The objective of this study was to compare cerebrospinal fluid (CSF) levels of the light subtype of the neurofilament proteins (NFL), tau, and beta-amyloid42 (Abeta42) in individuals with moderate or severe white matter changes (WMC) and in those with mild or no WMC. Twenty-two patients with Alzheimer's disease (AD), nine patients with subcortical vascular dementia (SVD), and 20 normal controls were included in the study. The occurrence of WMC was evaluated by a neuroradiologist using the Blennow-Wallin scale. Thirty-seven subjects had no or only punctate WMC; 14 had moderate to severe WMC. Both diagnostic group and WMC, but not gender or apolipoproteinE E4 inheritance, contributed to the variance in the CSF levels of tau, NFL, and Abeta42. In patients with moderate to severe WMC, CSF NFL (P < 0.01), but not CSF tau or CSF Abeta42, was increased also after correction for age, gender, and degree of cognitive impairment. A comparison between patients and controls with any signs of WMC and those without such signs yielded a similar result: CSF NFL (P < 0.001) was increased in the group with signs of WMC. As in numerous previous studies, we found that CSF tau was increased in AD (P < 0.001) compared with controls. Furthermore, CSF NFL was increased in both AD and SVD compared with controls (P < 0.001 for both). Although diagnostic group seems to be a stronger predictor of the variance found in CSF NFL, a clear association between the presence of WMC and increased CSF NFL was found. Because NFL is located mainly in large myelinated axons, increased CSF NFL in individuals with WMC probably reflects axonal degeneration.     

Cerebrospinal fluid and serum antibodies against neurofilaments in patients with amyotrophic lateral sclerosis

Background: The aim of the study was to assess autoimmune involvement in amyotrophic lateral sclerosis (ALS). Methods: We measured IgG antibodies against light (NFL) and medium (NFM) subunits of neurofilaments using ELISA in paired cerebrospinal fluid (CSF) and serum samples from 38 ALS patients and 20 controls. Results: Serum levels of anti‐NFL were higher in ALS patients than in controls (P < 0.005). Serum anti‐NFL antibodies and intrathecal anti‐NFM antibodies were related to patient disability (serum anti‐NFL: P < 0.05; intrathecal anti‐NFM: P < 0.05). Anti‐NFL levels were significantly correlated with anti‐NFM levels in ALS (P < 0.001) and the control group (P < 0.0001) in the CSF, but not in serum. Anti‐NFL and anti‐NFM antibodies significantly correlated between serum and CSF in the ALS group (anti‐NFL: P < 0.0001; anti‐NFM: P < 0.001) and in the control group (anti‐NFL: P < 0.05; anti‐NFM: P < 0.05). Conclusions: Autoimmune humoral response to neurocytoskeletal proteins is associated with ALS.     

Serum NFL levels predict progression of motor impairment and reduction in putamen dopamine transporter binding ratios in de novo Parkinson's disease: An 8-year longitudinal study

Neurofilament light chain (NFL) level in biofluids is a sensitive measure of axonal damage and a promising biomarker in neurodegenerative diseases. In Parkinson's disease (PD), NFL can distinguish PD from other parkinsonian disorders, and NFL concentration is associated with disease severity, risk of progression, and survival. To determine whether serum NFL at baseline in de novo PD predicts motor decline, differentially impacts specific motor features, predicts cognitive decline, and predicts loss of dopamine terminals, here we evaluated 376 de novo PD patients from the PPMI database and analyzed the effect of baseline serum NFL levels on progression over eight years of motor impairment measured with the UPDRS, cognitive function measured with the MoCA, and putamen dopamine transporter (DAT) binding ratio measured with DaTscan. In longitudinal mixed effects models that controlled for age, gender, disease duration, and levodopa equivalent drug dose, higher levels of serum NFL at baseline were associated with greater increases of UPDRS-III and total UPDRS scores, with greater worsening of postural instability and gait disorder (PIGD) scores but not tremor scores over time. In contrast, baseline serum NFL was not associated with significant progression of MoCA scores in this de novo PD cohort. Higher baseline serum NFL was associated with greater reduction of putamen DAT binding ratio over time. Together, these findings show that baseline serum NFL levels predict the rate of motor decline, the accumulation of PIGD clinical features, and the progression of dopamine transporter loss in the early stage of PD.     

Reduction of optic nerve fiber layer thickness in CADASIL

Our study aims to assess nerve fiber layer (NFL) thickness in patients affected by cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL). Six CADASIL patients (mean age 42 ± 16 years, best corrected visual acuity >20/20 with refractive error between ±3 diopters, intraocular pressure <18 mmHg) were enrolled. They were compared with 16 age-matched controls. In all subjects enrolled, NFL thickness was measured by optical coherence tomography (OCT). Three different measurements were taken in each quadrant (superior, inferior, nasal, and temporal) and averaged. The data from all quadrants (12 values averaged) were identified as NFL overall. In CADASIL eyes there was a reduction of NFL thickness in each quadrant and in the NFL overall evaluation compared with the values observed in control eyes. Our results suggest that in CADASIL patients there is a reduction of NFL thickness evaluated by OCT. This morphological abnormality could be ascribed to an impairment of the retinal vascular supply leading to a global neuroretinal involvement. These anatomical changes may precede the onset of the neurological clinical manifestations.     

Antibodies against light neurofilaments in multiple sclerosis patients

OBJECTIVES: Axonal damage in multiple sclerosis (MS) may be reflected by antibodies against axon-specific proteins - the light subunit of neurofilaments (NFL). MATERIALS AND METHODS: The serum and cerebrospinal fluid obtained from 58 MS patients, 24 normal controls (CN), 49 control patients with miscellaneous diseases (CD) and 31 patients with neurodegenerative disorders (CDEG) were tested for both immunoglobulin G and M antibodies against NFL, using an ELISA. RESULTS: Intrathecal IgG antibodies to NFL were elevated in MS patients compared with that in CD patients (P = 0.001) and were not related to clinical variables. No differences in IgM anti-NFL levels were found between the MS and CN/CD groups. IgM to NFL was higher in the CDEG group than in either the CD group or even the MS group (P < 0.0005). CONCLUSIONS - Intrathecal IgM or IgG antibodies to NFL are not useful surrogate markers for axonal damage or disease subtypes in MS.     

Immunohistochemical localization of laminin, fibronectin and collagen type IV in the nerve fiber layer of the olfactory bulb

When the olfactory nerve is injured in adult mammals, the axons grow across the PNS-CNS transitional zone and re-innervate their synaptic contacts within the olfactory bulb. Some years ago, Liesi [Liesi P. (1985) Laminin-immunoreactive glia distinguish regenerative adult CNS systems from non-regenerative ones.EMBO J.4, 2505–2511] reported the presence of laminin in non-basal lamina locations within the nerve fiber layer (NFL) of the olfactory bulb of adult rats and suggested that this molecule may facilitate olfactory axonal growth into and within the CNS. The purpose of the present study was to compare the expression of laminin, fibronectin, and collagen type IV in: (a) the NFL of developing and adult rats; and (b) the NFL rostral and caudal to a stab wound in the olfactory bulb of adult rats. Numerous punctate deposits of immunofluorescence were seen in the NFL of the E18 (Theiler stage 23) bulb when antisera to laminin, fibronectin or collagen type IV were used. There was a dramatic drop-off in staining at the border between the NFL and the presumptive glomerular layer. The staining pattern was similar in the newborn bulb, although the immunofluorescence was not as strong. In the unoperated adult rats, only laminin was present consistently as punctate deposits within the NFL, whereas all three antisera stained numerous punctate deposits within the NFL during the first week after a stab wound. Although there was a partial recapitulation of the expression pattern for laminin, fibronectin and collagen type IV in the lesioned adult NFL, it never reached the extent found in the E18 or newborn bulbs and its expression returned to normal levels prior to the re-innervation of the bulb during the second and third weeks after surgery. The results suggest that the molecular requirements for the successful growth of olfactory axons may differ during development to growth in adult animals.     

CSF levels of neurofilament is a valuable predictor of long-term outcome after cardiac arrest

AIMS: Prognostication of brain damage after cardiac arrest mainly relies on clinical observations. Recently, it has been shown that biochemical markers of brain damage measured in serum aid in this process. In the present study, we wanted to test the usefulness of CSF determinations of a neuronal protein, the neurofilament protein (NFL). METHODS AND RESULTS: Lumbar punctures were performed during week 2 or 3 in 22 patients surviving cardiac arrests. CSF NFL concentrations were analysed using an ELISA. Levels were increased in cardiac arrest patients. Patients with poor outcome according to the Glasgow outcome scale (GOS), low performance at a mini mental state examination (MMSE) and dependent according to Katz at 1 year follow up had the highest NFL levels. The NFL levels correlated well with anoxia time and coma depth. High positive and negative predictive values, particularly for poor outcome according to GOS were observed. CONCLUSIONS: Levels of CSF NFL give a reliable measure of the brain damage following cardiac arrest and the levels are highly predictive of poor outcome. This observation urges the development of sensitive serum assays of this marker to be used in the clinical setting.     

14-3-3 protein binds to the low molecular weight neurofilament (NFL) mRNA 3' UTR

We have previously reported that altered stability of low molecular weight neurofilament (NFL) mRNA in lumbar spinal cord homogenates in amyotrophic lateral sclerosis (ALS) is associated with altered expression of trans-acting 3' UTR mRNA binding proteins. We have identified two hexanucleotide motifs as the main cis elements and, using LC/MS/MS of peptide digests of NFL 3' UTR interacting proteins from human spinal cord, observed that 14-3-3 proteins interact with these motifs. 14-3-3 beta, zeta, tau, gamma, and eta isoforms were found to be expressed in human spinal cord. Each isoform was expressed in vitro and shown to interact with NFL 3' UTR mRNA. Mutation of one or both motifs resulted in decreased 14-3-3 interaction, changes in predicted mRNA structure or alteration in stability of the mRNA. These data show a novel interaction for 14-3-3 with NFL mRNA, and suggests that 14-3-3 may play a role in regulating NFL mRNA stability.     

Serum neurofilament light chain (NFL) remains unchanged during electroconvulsive therapy

Abstract

Objectives: Although there is consistent evidence that electroconvulsive therapy (ECT) is safe and well tolerated by the majority of patients, some authors still accuse ECT to inevitably cause brain damage and permanent memory loss, assertions that may increase patients’ worries about a useful treatment. Recently, the measurement of neurofilament light chain (NFL) in peripheral blood was technically implemented, permitting longitudinal analysis of this biomarker for axonal damage. NFL is part of the axonal cytoskeleton and is released into the CSF and peripheral blood in the context of neuronal damage.

Methods: In our study, blood from 15 patients with major depressive disorder receiving ECT was collected before the first ECT as well as 24?h and seven days after the last ECT, respectively. NFL concentrations were analysed using the ultrasensitive single molecule array (Simoa) technology.

Results: NFL concentrations did not differ between patients and healthy controls, and there was no significant change in NFL levels in the course of ECT. On the contrary, we even found a slight decrease in absolute NFL concentrations.

Conclusions: Our study confirms the safety of ECT by using a most sensitive method for the detection of NFL in peripheral blood as a biomarker of neuronal damage.     

Intrathecal immune activation is associated with cerebrospinal fluid markers of neuronal destruction in AIDS patients

We analysed the relationship between cerebrospinal fluid (CSF) concentrations of the light subunit of the neurofilament protein (NFL, a marker of neurons, mainly axons), neopterin (a marker of immune activation), and quantitative HIV RNA levels in 47 patients with HIV-1 infection, 25 of whom had AIDS. In the AIDS patients, the mean levels of CSF NFL were high indicating neuronal destruction. The CSF NFL and the CSF neopterin concentrations were correlated in the subgroup of patients without CNS opportunistic infection (p < 0.05). There was no significant correlation between NFL and HIV RNA levels in CSF. In HIV seropositive patients without AIDS, only 3/22 had CSF NFL concentrations above the upper normal reference value. The results suggest that CNS neuronal destruction occurs frequently in patients with AIDS but rarely in those without AIDS, and that immune activation rather than the HIV viral load is associated with neurochemical signs of axonal destruction.     

Consecutive analyses of cerebrospinal fluid axonal and glial markers in Parkinson's disease and atypical parkinsonian disorders

Cerebrospinal fluid (CSF) levels of neurofilament light protein (NFL), a marker of neuronal damage, are normal in Parkinson's disease (PD) but elevated in multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). Therefore, CSF NFL can help differentiate between PD on one hand and MSA/PSP on the other. In the present study of 10 patients with PD, 21 with MSA, 14 with PSP, 11 with corticobasal degeneration (CBD), and 59 healthy controls, this previous observation is confirmed and also extended to include CBD by showing that similarly high CSF NFL levels are seen not only in MSA and PSP but also in CBD. CSF levels of glial fibrillary acidic protein (GFAP), a protein expressed mainly in fibrillary astrocytes, were similar in all investigated groups. In addition, consecutive analyses of CSF NFL and CSF GFAP levels showed relatively stable levels over time in all the investigated parkinsonian disorders, suggesting that the rate of neuronal degeneration is rather constant over time. Our results suggest that measurements of CSF NFL but not GFAP can be useful in the differential diagnosis of PD versus atypical parkinsonian disorders (APD). However they do not help differentiate between the different APD.     

Astrocytes in the guinea pig, horse, and monkey retina: their occurrence coincides with the presence of blood vessels

In the present study the distribution of astrocytes in the nerve fiber layer (NFL) has been studied in the sparsely vascularized retinae of the guinea pig and horse and in the richly vascularized retina of the Old World monkey (Cercopithecus aethiops) using immunocytochemical methods. In the guinea pig retina glial fibrillary acidic protein (GFAP)-positive astrocytes could not be detected. They were found, however, in the myelinated region of the optic nerve. The optic nerve head and a small retinal region immediately adjacent to it contained few vimentin-positive astrocytes. Histological sections confirmed the restriction of astrocytes to a small retinal region and showed that this is also the only retinal area that is vascularized. Astrocytes showing GFAP and vimentin immunoreactivity were absent from most of the horse retina. They were found only in a narrow zone close to the optic disc, which is also the only region of the horse retina that is vascularized. Thus, as in the rabbit retina (Schnitzer: J. Comp. Neurol. 240:128-142, 1985), in the guinea pig and horse retina astrocytes are not present ubiquitously in the NFL but coexist with blood vessels. In the monkey retina, GFAP-positive astrocytes were found ubiquitously in the NFL. Astrocytes were absent from the avascular foveal region only. It is suggested that the concurrence of retinal astrocytes and intraretinal vascularization may be a feature common to many, if not all, mammalian species.     

Neurofilament protein levels in CSF are increased in dementia

The neurofilament is the major cytoskeletal structure of myelinated axons. In this study, CSF levels of the light subunit of the neurofilament protein (NFL) were increased in patients with vascular dementia (VAD), AD, and frontotemporal dementia (FTD) compared with neurologically healthy individuals. Because NFL is localized mainly in myelinated axons, these results suggest that the degeneration of white matter in these disorders causes the increased CSF NFL levels.     

Morphological and functional retinal impairment in Alzheimer's disease patients.

OBJECTIVE: Our study aims to assess the optic nerve fiber layer thickness in vivo, the function of the innermost retinal layer and whether a correlation exists between morphological and functional parameters in patients affected by Alzheimer's Disease (AD). METHODS: Seventeen AD patients (mean age 70.37+/-6.1 years, best corrected visual acuity >8/10 with refractive error between +/-3 sf, intra-ocular pressure (IOP)<18 mmHg) were enrolled. They were compared to 14 age-matched controls. Nerve fiber layer (NFL) thickness was measured by optical coherence tomography (OCT). Three different measurements in each quadrant (superior, inferior, nasal, and temporal) were taken and averaged. The data in all quadrants (12 values averaged) were identified as NFL Overall. Retinal function was assessed by pattern electroretinogram (PERG) recordings using high-contrast (80%) checkerboard stimuli subtending 15 min of the visual arc and reversed at the rate of two reversals/s. RESULTS: In AD eyes, there was a significant (P<0.01) reduction in NFL thickness in each quadrant and in the NFL Overall evaluation compared with the values observed in control eyes. PERGs showed a significant (P<0.01) delay in N35, P50 and N95 implicit times, and reduction in N35-P50 and P50-N95 amplitudes. NFL Overall values were significantly correlated (P<0.01) to the PERG P50 and N95 implicit times and P50-N95 amplitude. No correlations (P>0.01) between NFL values and other PERG parameters (N35 implicit time, N35-P50 amplitude) were found. CONCLUSIONS: Our results suggest that in AD patients, there is a reduction of NFL thickness evaluated in vivo by OCT and this morphological abnormality is related to a retinal dysfunction as revealed by abnormal PERG responses.     

血清NFL水平与脑小血管病病人认知功能障碍的关系

目的 探讨血清神经丝蛋白轻链（NFL）水平与脑小血管病（CSVD）病人认知功能障碍的关系。方法 2019年6月至2021年6月前瞻性收集CSVD共186例,用简易精神状态检查量表评估认识功能,ELISA检测血清NFL水平。结果 186例中,存在认知功能障碍104例,认知功能正常82例。认知功能障碍发生率为55.91%。多因素lgistic回归分析显示,血清NFL水平（OR=3.128;95%CI 1.361～6.021,P=0.012）是CSVD病人认知功能障碍的独立危险因素。ROC曲线分析显示,血清NFL评估CSVD病人认知功能障碍的曲线下面积为0.84(95%CI 0.712～0.921)。结论 CSVD病人认知功能障碍发生率较高,血清NFL水平与CSVD病人认知功能障碍密切相关。     

Cerebrospinal fluid neurofilament and glial fibrillary acidic protein in patients with cerebral vasculitis

Few diseases in clinical medicine cause as much diagnostic consternation as central nervous system (CNS) vasculitis because of its varying modes of presentation and frequently overlapping clinical and pathological features. There are no pathognomonic clinical or laboratory findings. The purpose of the present retrospective study was to validate the use of the light subunit of neurofilament triplet protein (NFL) and glial fibrillary acidic protein (GFAP) as markers of CNS tissue damage for patients with systemic or isolated CNS vasculitis. Levels of cerebrospinal fluid (CSF) NFL and GFAP were measured using ELISAs. Both CSF NFL and CSF GFAP concentrations were significantly higher in a patient group diagnosed with CNS vasculitis (P < 0.01 and P < 0.05, respectively) than in a patient group for whom CNS vasculitis was excluded. In the future, analysis of CSF NFL in particular, but also GFAP, may be a useful complement in the difficult clinical task of diagnosing CNS vasculitis.